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C 25 – 06

Designation:C25–06

Standard Test Methods for

Chemical Analysis of Limestone,Quicklime,and Hydrated Lime1

This standard is issued under the?xed designation C25;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense.

1.Scope

1.1These test methods cover the chemical analysis of high-calcium and dolomitic limestone,quicklime,and hy-drated lime.These test methods are classi?ed as either standard (preferred)or alternative(optional).

1.2The standard test methods are those that employ classi-cal gravimetric or volumetric analytical procedures and are typically those required for referee analyses where chemical speci?cation requirements are an essential part of contractual agreement between buyer and seller.

1.3Alternative or optional test methods are provided for those who wish to use procedures shorter or more convenient than the standard methods for the routine determinations of certain constituents.Optional test methods may sometimes be preferred to the standard test methods,but frequently the use of modern and expensive instrumentation is indicated which may not be accessible to everyone.Therefore,the use of these test methods must be left to the discretion of each laboratory. 1.4The analytical procedures appear in the following order:

Section

Aluminum Oxide15

Available Lime Index28

Calcium and Magnesium Oxide:

Alternative EDTA Titration Method31

Calcium Carbonate Equivalent33

Calcium Oxide:

Gravimetric Method16

Volumetric Method17

Carbon Dioxide by Standard Method22

Combined Oxides of Iron and Aluminum12

Ferrous Iron Appendix X5

Free Calcium Oxide Appendix X6

Free Moisture in Hydrated Lime21

Free Moisture in Limestone20

Free Silica29

Insoluble Matter Including Silicon Dioxide:

Standard Method8

Optional Perchloric Acid Method9

Insoluble Matter Other Than Silicon Diox-

ide

Loss on Ignition19

Magnesium Oxide18Manganese:

Bismuthate Method Appendix X4

Periodate(Photometric)Method27

pH Determination of Alkaline Earth Solu-

tions

Phosphorus:

Titrimetric Method Appendix X3 Molybdovanadate Method26

Silicon Dioxide10

Strontium Oxide Appendix X2

Sulfur Trioxide23

Total Carbon:

Direct Combustion-Thermal Conductiv-

ity Cell Method

Total Carbon and Sulfur:

Combustion/Infrared Detection Method35

Total Iron:

Standard Method,Potassium Dichro-

mate Titration

Potassium Permanganate Titration

Method

Appendix X1

Ortho-Phenanthroline,Photometric

Method

Total Sulfur:

Sodium Carbonate Fusion24

Combustion-Iodate Titration Method25

Unhydrated Oxides30

1.5This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For speci?c precautionary statements,see9.3,10.

2.1,18.4.3,31.6.4.2, X2.

3.1,and X5.

4.1.1.

2.Referenced Documents

2.1ASTM Standards:2

C50Practice for Sampling,Sample Preparation,Packag-ing,and Marking of Lime and Limestone Products

C51Terminology Relating to Lime and Limestone(as used by the Industry)

C911Speci?cation for Quicklime,Hydrated Lime,and Limestone for Chemical and Industrial Uses

1These test methods are under the jurisdiction of ASTM Committee C07on Lime and are the direct responsibility of Subcommittee C07.05on Chemical Tests.

Current edition approved Feb.15,2006.Published March2006.Originally approved https://www.wendangku.net/doc/e511989145.html,st previous edition approved in1999as C25–99.

2For referenced ASTM standards,visit the ASTM website,https://www.wendangku.net/doc/e511989145.html,,or contact ASTM Customer Service at service@https://www.wendangku.net/doc/e511989145.html,.For Annual Book of ASTM Standards volume information,refer to the standard’s Document Summary page on the ASTM website.

D1193Speci?cation for Reagent Water

E29Practice for Using Signi?cant Digits in Test Data to Determine Conformance with Speci?cations

E50Practices for Apparatus,Reagents,and Safety Consid-erations for Chemical Analysis of Metals,Ores,and Related Materials

E70Test Method for pH of Aqueous Solutions With the Glass Electrode

E173Practice for Conducting Interlaboratory Studies of Methods for Chemical Analysis of Metals3

E200Practice for Preparation,Standardization,and Stor-age of Standard and Reagent Solutions for Chemical Analysis

E691Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

E832Speci?cation for Laboratory Filter Papers

3.Terminology

3.1De?nitions—Unless otherwise speci?ed,for de?nitions of terms used in these test methods refer to Terminology C51.

4.Signi?cance and Use

4.1These test methods provide accurate and reliable ana-lytical procedures to determine the chemical constituents of limestone,quicklime,and hydrated lime(See Note1).The percentages of speci?c constituents which determine a materi-al’s quality or?tness for use are of signi?cance depending upon the purpose or end use of the material.Results obtained may be used in relation to speci?cation requirements.

4.2Because quicklime and hydrated lime quickly absorb water and carbon dioxide from the air,precision and bias are extremely dependent upon precautions taken during sample preparation and analysis to minimize excessive exposure to ambient conditions.

N OTE1—These test methods can be applied to other calcareous materials if provisions are made to compensate for known interferences.

5.General Apparatus and Materials and Reagents

5.1General Apparatus and Materials:

5.1.1Balance—The balance shall be of an analytical type with a capacity not to exceed200g.It may be of conventional design or it may be a constant-load,direct-reading type.It shall be capable of reproducing weighings within0.0002g with an accuracy of60.0002g.Rapid weighing devices that may be provided such as a chain,damper,or heavy riders shall not increase the basic inaccuracy by more than0.0001g at any reading and with any load within the rated capacity of the balance.

5.1.2Weights—Weights used for analysis shall conform to Class S-1requirements of the National Institute of Standards and Technology as described in NIST Circular547.4They shall be checked at least once a year or when questioned,and adjusted to within allowable tolerances for Class S-1weights. All new sets of weights purchased shall have the weights of1g and larger made of stainless steel or other corrosion-resistant alloy not requiring protective coating and shall meet the density requirements for Class S.

5.1.3Glassware and Laboratory Containers—Standard volumetric?asks,burets,pipets,dispensers,etc.,shall be carefully selected precision grade or better and shall be calibrated,if necessary,to meet the requirements of each operation.Standard-type interchangeable ground glass or TFE-?uorocarbon joints are recommended for all volumetric glass-ware.Polyethylene containers are recommended for all aque-ous solutions of alkalies and for standard solutions where the presence of dissolved silica or alkali from the glass would be objectionable.

5.1.4Desiccators—Desiccators shall be provided with a good desiccant such as anhydrous magnesium perchlorate, activated alumina,sulfuric acid,or phosphoric anhydride. Anhydrous calcium sulfate may also be used provided it has been treated with a color-changing indicator to show when the desiccant has lost its effectiveness.Calcium chloride and silica gel are not satisfactory desiccants for this type of analysis. 5.1.5Filter Paper—Filter paper shall conform to the re-quirements of Speci?cation E832,Type II(quantitative).Class E shall be used for coarse and gelatinous precipitates.When medium-textured paper is required,Class F?lter paper shall be used.When a retentive paper is needed,Class G shall be used.

Recommendations:

Class

Filter Pore Size

(microns)

Filter Speed E20to25fast speed

F8medium speed

G 2.5slow speed

5.1.6Crucibles—Platinum crucibles and tight?tting lids should preferably be made of pure unalloyed platinum and be of25to35-mL capacity.Where alloyed platinum is used for greater stiffness or to obviate sticking of fused material to crucible or lid,the alloyed platinum should not decrease in weight by more than0.2mg when heated at1200°C for1h.

5.1.7Muffle Furnace—The electric muffle furnace should be capable of continuous operation up to1000°C and be capable of intermittent operation at higher temperatures if required.It should have an indicating pyrometer accurate to 625°C.

5.2Reagents:

5.2.1Purity of Reagents—Reagent grade chemicals shall be used in all tests.Unless otherwise indicated,it is intended that all reagents shall conform to the speci?cations of the Commit-tee on Analytical Reagents of the American Chemical Society5 where such speci?cations are available.Other grades may be used provided it is?rst ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.In addition to this,it is desirable in many cases for the analyst to ensure the accuracy of his results by running blanks or checking against a comparable sample of known composition.

3Withdrawn.

4Available from National Institute of Standards and Technology(NIST),100 Bureau Dr.,Stop3460,Gaithersburg,MD20899-3460.

5Reagent Chemicals,American Chemical Society Speci?cations,American Chemical Society,Washington,DC.For suggestions on the testing of reagents not listed by the American Chemical Society,see Analar Standards for Laboratory Chemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeia and National Formulary,U.S.Pharmacopeia Convention,Inc.(USPC),Rockville,

MD.--` ` ` , ` ` , , ` , ` ` , ` , , , , ` ` ` ` ` , , , ` , ` -` -` , , ` , , ` , ` , , ` ---

5.2.2Purity of Water—Unless otherwise indicated,refer-ences to water are understood to mean distilled water or other water of equivalent purity.Water conforming to Speci?cation D1193meets these requirements.

5.2.3Concentration of Reagents:

5.2.3.1Concentrated Acids and Ammonium Hydroxide—When acids and ammonium hydroxide are speci?ed by name or chemical formula only,it shall be understood that concen-trated reagents approximating the following speci?c gravities or concentrations are intended:

Acetic acid(HC2H3O2)99.5%

Hydrochloric acid(HCl)sp gr1.19

Hydro?uoric acid(HF)48%

Nitric acid(HNO3)sp gr1.42

Perchloric acid(HClO4)70%

Phosphoric acid(H3PO4)85%

Sulfuric acid(H2SO4)sp gr1.84

Ammonium hydroxide(NH4OH)sp gr0.90

5.2.3.2Dilute Reagents—The concentration of dilute acids and NH4OH except when standardized,are speci?ed as a ratio stating the number of measured volumes of the concentrated reagent to be diluted with a given number of measured volumes of water.In conformance with international practice,new and revised methods will use the“plus”designation instead of the ratio(:)symbol as the speci?ed designation of dilution;for example,H2SO4(5+95)means5volumes of concentrated H2SO4(sp gr1.84)diluted with95volumes of water.

5.2.3.3Standard Solutions—Concentrations of standard so-lutions shall be expressed as normalities(N)or as equivalents in grams per millilitre of the component to be determined,for example:0.1N K2Cr2O7solution(1mL=0.004g Fe2O3).The average of at least three determinations shall be used for all standardizations.The standardization used to determine the strength of the standard solutions is described in the text under each of the appropriate procedures.

6.General Procedures

6.1Sampling—Samples of lime and limestone for chemical analysis shall be taken and prepared in accordance with the requirements of Practice C50applicable to the material to be tested.

6.2Tared or Weighed Crucibles—The tare weight of cru-cibles shall be determined by preheating the empty crucible to constant weight at the same temperature and under the same conditions as shall be used for the?nal ignition of a residue and cooling in a desiccator for the same period of time used for the crucible containing the residue.

6.3Constancy of Weight of Ignited Residue—To de?nitely establish the constancy of weight of the ignited residue,the residue and container shall be ignited at the speci?ed tempera-ture and time,cooled to room temperature in a desiccator,and weighed.The residue and container shall then be reheated for at least30min at the same temperature,cooled in a desiccator for the same period of time,and reweighed.Additional ignition periods may be required until two consecutive weights do not differ by more than0.2mg,at which time it shall be considered that constant weight has been attained.For ignition loss,each reheating period shall be5min.

6.4Calculation:

6.4.1The calculations included in the individual procedures sometimes assume that the exact weight speci?ed has been used.Accurately weighed samples which are approximately but not exactly equal to the weight speci?ed may be used provided appropriate corrections are made in the calculation. Unless otherwise stated,weights of all samples and residues should be recorded to the nearest0.0001g.

6.4.2In all mathematical operations on a set of observed values,the equivalent of two more places of?gures than in the single observed values shall be retained.For example,if observed values are read or determined to the nearest0.1mg, carry numbers to the nearest0.001mg in calculation.

6.5Rounding Figures—Rounding?gures to the nearest signi?cant place required in the report should be done after the calculations are completed,in order to keep the?nal results free from calculation errors.The rounding procedure should follow the principle outlined in Practice E29.

7.Performance Requirements for Test Methods

7.1Referee Analyses—The reference test methods that ap-pear in Sections8through32,or any other test methods quali?ed in accordance with7.3,are required for referee analysis in those cases where conformance to the requirements of a chemical speci?cation are questioned.In these cases a limestone,quicklime,or hydrated lime shall not be rejected for failure to conform to chemical requirements unless all sample preparation and analysis of any one constituent is made entirely by reference test methods prescribed in the appropriate sections of this test method or by other quali?ed test methods.Excep-tion can be made when speci?c test methods are prescribed in the standard speci?cation for the limestone,quicklime,or hydrated lime in question.The test methods actually used for the analysis shall be designated.

7.1.1When there is a question regarding acceptance,referee analyses shall be made in duplicate.If the two results do not agree within the permissible variation given in Table1,the determination including sample preparation shall be repeated TABLE1Maximum Permissible Variations in Results A

(Column1)

Constituent

(Column2)

Maximum Difference

Between Duplicates

(Column3)

Maximum Difference of

the Average of Duplicates

from SRM Certi?cate

Values B

Al as Al2O30.2060.30

Ca as CaO0.2060.30

Mg as MgO0.2060.30

C(lime and hydrated lime)0.2060.30

C(limestone)0.6060.60

Fe as Fe2O30.1060.15

Si as SiO20.1560.30

Mn0.0560.10

P0.0260.05

Sr as SrO0.05C

S0.0360.05

A For demonstrating the performance of rapid test methods the SRM closest in overall composition to the limestone shall be used(See Table2).In the case of quicklime or hydrated lime,the SRM closest in overall composition,after heating at1000°C for1h,to the product composition shall be used,except for C and S determinations(See Note3).

B Interelement corrections may be used for any standardization provided improved accuracy can be demonstrated.

C No SRM currently

available.--` ` ` , ` ` , , ` , ` ` , ` , , , , ` ` ` ` ` , , , ` , ` -` -` , , ` , , ` , ` , , ` ---

in duplicate until the results agree within the permissible variation.When the results agree within the permissible variation,their average shall be accepted as the correct value.For the purpose of comparing results,the percentages shall be calculated to one more signi?cant ?gure than reported as indicated in the test methods.When a blank determination is speci?ed,one shall be made with each individual analysis or with each group of two or more samples analyzed on the same day for a given constituent.

7.1.2Test results from Referee methods intended for use as a basis for product acceptance or rejection,or for manufactur-er’s certi?cation,can be used only after demonstration of precise and accurate analyses by meeting the requirements of 7.1.3,or except when demonstrated under 7.3.2.1.Such dem-onstrations may be made concurrently with analysis of the limestone,quicklime,or hydrated lime product being tested.The demonstration is required only for those constituents being used as a basis for acceptance,rejection,or certi?cation of a limestone,quicklime,or hydrated lime,but may be made for any constituent of limestone,quicklime,or hydrated lime product for which a standard exists.Such demonstrations must be made annually.

7.1.3Demonstrations shall be made by analysis of each constituent of concern in a SRM limestone,quicklime,or hydrated lime (See Notes 2and 3).Duplicate samples shall be run on different days.The same test methods to be used for analysis of the limestone,quicklime,or hydrated lime being tested shall be used for analysis of the SRM.If the duplicate results do not agree within the permissible variation given in Table 1,the determinations shall be repeated,following iden-ti?cation and correction of problems or errors,until a set of duplicate results do agree within the permissible variation.

N OTE 2—The term SRM refers to approved Standard Reference Mate-rials listed in Table 2.

N OTE 3—There are no SRMs that are quicklime or hydrated lime as supplied.When analyzing a quicklime or hydrated lime the SRM in carbonate form needs to be converted to closely resemble the matrix of the product being tested.To accomplish this conversion,heat the chosen SRM for 1h at 1000°C,immediately prior to analysis and protect it from

hydration or carbonation with sealed containers and desiccation during cooling.Carbon and sulfur may be driven off during heating,rendering the converted SRM unsuitable as a standard for carbon and sulfur determi-nations.For carbon and sulfur determinations use the appropriate SRM in its normal matrix.

7.1.4The average of the results of acceptable duplicate determinations for each constituent may differ from the SRM certi?cate value by no more than the value shown in Column 3of Table 1.When no SRM certi?cate value is given,a generally accepted accuracy standard for that constituent has not been identi?ed.In such cases,only the differences between duplicate values as speci?ed in 7.1.3shall apply and noti?ca-tion of this exception shall be reported.

7.1.5In questions concerning the acceptance or rejection of a limestone,quicklime,or hydrated lime product,upon request data shall be made available to all parties involved demonstrat-ing that precise and accurate results were obtained with SRM samples by the same analyst making the acceptance determi-nation.

7.2Optional Analyses —The alternative test methods,as opposed to reference methods,provide procedures that are,in some cases,shorter or more convenient to use for routine determination of some constituents (See Note 4).In some instances longer,more complex procedures have been retained as alternative test methods to permit comparison of results by different procedures or for use when unusual materials are being examined,or when unusual preparation for analysis is required.Results from alternative test methods may be used as a basis for acceptance or rejection.

N OTE 4—It is not intended that the use of reference test methods be con?ned to referee analysis.A reference test method may be used in preference to an alternative test method when so desired.A reference test method must be used where an alternative test method is not provided.

7.2.1Duplicate analyses and blank determinations are left to the discretion of the analyst when using the alternative test methods.The ?nal results should include the number of determinations performed and whether or not they were corrected for blank values.

TABLE 2Approved SRM List

(SRM)Al as %Al2O3

Ca as %CaO Mg as %MgO Fe as %Fe2O3Si as %SiO2%Mn %P Sr as %SrO %S Ti as %TiO2K as %K2O Na as %Na 2O %L.O.I.ECRM-752-1A

0.1255.40.150.0450.700.008NC B

0.0190.0070.0090.02NC 43.4IPT 350.2453.80.700.14 1.980.0090.0030.04NC 0.0130.100.00443.0IPT 44

0.3350.5 2.930.30 2.690.0120.0060.04NC 0.0190.120.00242.9IRSID DO 1-1C 0.5552.690.60 1.04 1.990.0220.022NC 0.0400.030NC NC NC NIST 1C 1.3050.30.420.55 6.840.0190.0170.030NC 0.070.280.02039.9NIST 88B 0.3429.9521.00.277 1.130.0120.0020.0076NC (0.016)D 0.1030.029(46.98)BCS 3680.1730.820.90.230.920.05NC 0.0089NC <0.01NC (<0.01)46.7IRSID 702-10.4030.0520.510.629 2.220.0980.024NC 0.0270.022NC NC NC GBW 072140.01754.950.670.0710.380.0070.0011NC 0.020NC NC NC 43.57GBW 072150.5051.56 2.670.292 1.170.0140.0013NC 0.196NC NC NC 43.22GBW 072160.02736.5516.590.2260.0920.0220.0018NC 0.014NC NC NC 46.23GBW 072170.29530.6020.730.3760.960.0480.0012NC 0.174NC NC NC 46.30GBW 031060.6450.38 2.280.29 4.380.00550.006NC 0.0060.0340.140.07041.58GBW 031080.8847.49 3.63 1.97 3.840.150.017NC 0.0360.140.230.02441.52IPT 48

0.17

31.0

21.2

0.17

0.45

0.011

0.0096

0.009

0.006

0.026

0.013

46.9

A This SRM is still available,but its name has been changed from BCS 393to ECRM 752-1.B

NC =not certi?ed.C

This SRM has been found to be unavailable commercially.The use of private stock,though,is still allowed.D

()=not certi?ed,data for information

only.

7.3Performance Requirements for Alternative Test Meth-ods:

7.3.1De?nition and Scope—When analytical data obtained in accordance with this section is required,any test method may be used that meets the requirements of7.3.2.A test method is considered to consist of the speci?c procedures, reagents,supplies,equipment,instrument,etc.selected and used in a consistent manner by a speci?c laboratory.

7.3.1.1If more than one instrument is used for the same analysis,use of each instrument shall constitute a separate test method and each must be quali?ed separately.

7.3.2Quali?cation of a Test Method—Prior to use each test method(See7.3.1)must be quali?ed for each material that will be tested.Quali?cation data or,if applicable,requali?cation data shall be made available.

7.3.2.1Using the test method chosen,make single determi-nations for each constituent under consideration on the SRM which in overall composition most closely resembles the limestone,quicklime,or hydrated lime to be tested(See Note 2).Complete two rounds of tests on nonconsecutive days repeating all steps of sample preparations.Calculate the differences between values and the averages of values from the two rounds of tests.Blank determinations are not required,if it has been determined that blank values do not affect the validity of the data.Blank or interference-corrected data must be so designated.

7.3.2.2The differences between duplicates obtained for any single constituent shall not exceed the limits shown in Column 2of Table1.

7.3.2.3For each constituent the average of the duplicates obtained shall be compared to the SRM Certi?cate value and shall not differ from the certi?ed value by more than the value in Column3of Table1.The quali?cation testing shall be conducted with newly prepared specimens.

7.3.2.4The standardization,if applicable,used for quali?-cation and analysis of each constituent shall be determined by valid curve-?tting procedures(See Note5).Restandardization shall be performed as frequently as required to ensure that the accuracy and precision in Table1are maintained.

N OTE5—An actual drawing of a curve is not required,if such a curve is not needed for the method in use.A point-to-point,saw-tooth curve that is arti?cially made to?t a set of data points does not constitute a valid curve-?tting procedure.

7.3.3Partial Results—Test methods that provide acceptable results for some constituents,but not for others,may be used only for those components for which acceptable results are obtained.

7.3.4Report of Results—Chemical analyses obtained by quali?ed alternative test methods shall be indicated as having been obtained by alternative methods and the type of test method used shall be designated.

7.3.5Rejection of Material—See7.1and7.2.

7.3.6Requali?cation of a Test Method:

7.3.6.1Requali?cation of a test method,as de?ned in7.3.2, shall be required annually.

7.3.6.2Requali?cation also shall be required upon receipt of substantial evidence that the test method may not be providing data in accordance with Table1.Such requali?cation may be limited to those constituents indicated to be in error and shall be carried out prior to further use of the method for analysis of those constituents.

7.3.6.3Substantial evidence that a test method may not be providing data in accordance with Table1shall be considered to have been received when a laboratory is informed that analysis of the same material by Reference Test Methods run in accordance with7.1.1,a certi?ed value of an approved SRM, or an accepted value of a known secondary standard differs from the value obtained by the test method in question by more than twice the value of Column2of Table1for one or more constituents.When indirect test methods are involved,as when a value is obtained by difference,corrections shall be made for minor constituents in order to put the analyses on a comparable basis prior to determining the differences(See Note6).For any constituents affected,a test method also shall be requali?ed after any substantial repair or replacement of one or more critical components of an instrument essential to the test method.

N OTE6—Instrumental analyses can usually detect only the element sought.Therefore,to avoid controversy,the actual procedure used for the elemental analysis should be noted when differences with reference procedures exist.For example,Combined Oxides of Iron and Aluminum by Wet Test should be compared to the sum of Fe

and Al

obtained instrumentally.

7.3.6.4If an instrument or piece of equipment is replaced even by one of identical make and model,or is signi?cantly modi?ed,a previously quali?ed test method using such new or modi?ed instrument or equipment shall be considered a new method and must be quali?ed in accordance with7.3.2.

7.4Precision and Bias—Different analytical test methods are subject to individual limits of precision and bias.It is the responsibility of the user to demonstrate that the test methods used at least meet the requirements shown in Table1.

8.Insoluble Matter Including Silicon Dioxide(Standard

Method)

8.1Scope—This test method is based on a double evapora-tion to dryness of the hydrochloric acid solution of the limestone or lime sample to convert silicon dioxide(SiO2)to the insoluble form.The acid-insoluble residue of a typical limestone consists of free silica and a mixture of minerals such as clay,mica,feldspar,tourmaline,barytes,garnet,zircon, rutile,etc.

8.2Summary of Test Method—After dissolution in hydro-chloric acid,the silica is dehydrated by a double evaporation to dryness.After each dehydration,the dry salts are redissolved with dilute hydrochloric acid,the solution is?ltered,and the siliceous residue and other insoluble matter separated.The two papers containing the residues are combined,ignited,and weighed.

8.3Procedure:

8.3.1Weigh0.5g of quicklime or hydrated lime,or1.0g of limestone ground to pass a No.50(250-μm)sieve(See Note7). If the sample is a limestone or hydrated lime,ignite in a covered platinum crucible in an electric muffle(See Note8)at 950°C for15min or longer to effect complete decomposition. Transfer to an evaporating dish,preferably of platinum(See Note9),containing about10mL of water,mix to a thin

slurry,

add5to10mL of HCl,and digest with the aid of gentle heat and agitation until solution is complete(See Note10).

N OTE7—Due to the rapidity with which quicklime and hydrated lime absorb water and carbon dioxide from the air,samples must be protected in tightly stoppered containers at all times.Samples for analysis are to be weighed quickly and the sample container re-stoppered immediately after the sample has been removed.

N OTE8—Ignition of the sample in an electric muffle is far superior to ?ame ignition.However,if an electric muffle is not available,?ame ignition and the blast lamp may be used.

N OTE9—If a platinum dish is not available,porcelain may be used.A glass container positively must not be used.

N OTE10—Alternatively,the loss on ignition(LOI)can be determined ?rst,using0.5g of sample.The insoluble matter including silicon dioxide can then be assayed using the ignited product that remains in the LOI crucible.

8.3.2Evaporate the solution to dryness on a steam bath. When dry or nearly so,cover the dish and place it in an air bath or drying oven or on a metal triangle resting on a hot plate. Heat for1h at100°C,remove the dish from the heat,and allow the dish and contents to cool slightly.

8.3.3Drench the cooled mass with20mL(1+1)HCl and place on the water bath for10min.Filter the mixture containing the insoluble residue through a retentive?lter of suitable size.Wash?lter thoroughly with warm,diluted (5+95)HCl and then twice with hot water.Reserve the paper and residue.

8.3.4Evaporate the?ltrate to dryness,dehydrate and extract the residue with HCl as before,but this time heat the acidi?ed solution for1to2min.Filter through a second and smaller piece of retentive?lter paper and wash as before.Retain the ?ltrate for iron,aluminum,calcium,and magnesium determi-nations;combine the two wet papers containing the separated residues and transfer to a weighed platinum crucible.

8.3.5Char carefully without allowing the paper to in?ame, and then ignite at1000°C for30min in an electric muffle furnace(See Note8).Cool in a desiccator and weigh.The increase in weight represents the insoluble matter including SiO2.

8.4Calculation—Calculate the percentage of insoluble mat-ter including silicon dioxide to the nearest0.01%as follows: Insoluble matter including SiO25~A/B!3100(1)

where:

A=mass of ignited residue,g,and

B=original mass of sample,g.

8.5Precision and Bias—This test method was originally approved for publication before the inclusion of precision and bias statements within standards was mandated.The user is cautioned to verify by the use of reference materials,if available,that the precision and bias of this test method are adequate for the contemplated use.

9.Insoluble Matter Including Silicon Dioxide(Optional

Perchloric Acid Method)

9.1Scope—In this test method the insoluble matter includ-ing silicon dioxide is determined gravimetrically as in the standard method except that perchloric acid is used to dehy-drate the silica.The procedure is more rapid than in the standard method because only a single dehydration is neces-sary.Fuming perchloric acid is a very powerful dehydrating agent,and silicic acid can usually be completely converted to the insoluble silicon dioxide in less than20min.This test method has been determined by other agencies such as the Association of Official Agricultural Chemists(AOAC)to be comparable to the standard hydrochloric acid method.

9.2Summary of Test Method—The sample is decomposed without prior ignition by a mixture of nitric(HNO3)and perchloric(HClO4)acids and evaporated to fumes of HClO4. The fuming perchloric acid is re?uxed at this temperature for a short period of time to completely dehydrate the silica.The residue of silica and insoluble matter is?ltered and washed free of acids and salts.The?lter paper containing the residue is burned off,the resultant ash is ignited at high temperature until the ash is white,and then is weighed.

9.3Procedure:

Warning—Perchloric acid(HClO4)is an extremely reactive liquid.When using HClO4,there are precautions to be fol-lowed which,if unheeded,may lead to serious explosions. Contact of the hot concentrated acid with organic matter must be absolutely avoided.Any organic matter in the sample must ?rst be destroyed by the addition of nitric acid(HNO3)to the sample prior to fuming with HClO4.All evaporations involving HClO4must be done in a well-ventilated hood made of nonporous and inorganic material,preferably Type316L stain-less steel.Facilities should be provided for washdown proce-dures that should be performed regularly and thoroughly.These precautions on perchloric acid use are fully discussed in Practices E50.

9.3.1Weigh0.5g of quicklime or hydrated lime,or1g of limestone ground to pass a No.50(250-μm)sieve.Transfer the sample to a250-mL beaker,wet carefully with a few millilitres of water,and dissolve cautiously with10mL of concentrated nitric acid.Add20mL of perchloric acid and boil until dense white fumes appear.If the solution darkens at this point,add several millilitres of HNO3until the solution clears.Heat again to fumes.

9.3.2With the beaker covered,boil gently for15min to completely dehydrate the silica.Never allow contents to become solid or go to dryness,otherwise the separation of silica will be incomplete.If this happens,add more HClO4and repeat the dehydration.

9.3.3Cool,add50mL of water,heat to boiling,and?lter immediately using medium textured paper.Wash paper and residue thoroughly(at least15times)with hot water.Test with pH paper until washings are free of acid(See Note11).Reserve the?ltrate for iron,aluminum,calcium,and magnesium determinations.

N OTE11—The?lter paper and silica residue must be washed free of perchlorate salts to prevent small explosions from occurring in the crucible when the?lter paper is charred and ignited.

9.3.4Place the?lter paper and contents in a weighed platinum or porcelain crucible and heat gently with a low?ame until paper chars without in?aming,or alternatively char in an electric muffle at300to400°C.Slowly raise the temperature until the carbon has been burned and the ash is white.Finally, ignite at1000°C for30min.Cool in a desiccator and weigh as insoluble matter including SiO2

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9.4Calculation —Calculate the percentage of insoluble mat-ter including silicon dioxide to the nearest 0.01%as follows:

Insoluble matter including SiO 2,%5~A/B !3100

(2)

where:

A =mass of ignited residue,g,and

B =original mass of sample,g.9.5Precision and Bias :

9.5.1Four laboratories cooperated in testing on four lime-stone samples and three laboratories cooperated in testing on an additional eight limestone samples thereby obtaining the precision data summarized in Table 3.

9.5.2The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

10.Silicon Dioxide

10.1Scope —For control purposes or routine determina-tions,a separate analysis of SiO 2may not be necessary.However,for certain applications in process industries,the amount of silica derived from the lime or limestone could be important.To satisfy situations such as this,silicon dioxide may be determined by volatilizing the SiO 2from the insoluble residue with hydro?uoric acid and the percent SiO 2determined by the difference in mass obtained.10.2Procedure :

10.2.1To the ignited residue in the platinum crucible (See 8.3.5or 9.3.4),add 5mL of water,5mL of hydro?uoric acid (HF),and 1or 2drops of H 2SO 4.

Warning —All acids should be handled with care,but extra precaution is required with hydro?uoric acid.This is a very dangerous acid,harmful to eyes and skin;rubber gloves and goggles should be worn when using this acid.It does its work silently and leaves a festering sore that is slow to heal.Any acid that touches the skin should be immediately washed off with copious quantities of water.A physician should be noti?ed immediately if any acid is sprayed into the eyes or if prolonged contact with the skin occurs.

10.2.2Evaporate to dryness on a hot plate and heat in an electric muffle at 1000°C (See Note 8)for 2or 3min.Cool in a desiccator and weigh.The difference between this mass and the mass of insoluble matter including silicon dioxide is the mass of SiO 2.

10.3Calculation —Calculate the percent of silicon dioxide to the nearest 0.01%as follows:

SiO 2,%5~@A 2B !/C ]3100

(3)

where:

A =mass of ignited residue,g (insoluble matter including

SiO 2),

B =mass of ignited residue less SiO 2,g,and

C =original mass of sample,g.10.4Precision and Bias :

10.4.1Three laboratories cooperated in testing on four limestone samples and two laboratories cooperated in testing on an additional eight limestone samples thereby obtaining the precision data summarized in Table 3.

10.4.2The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

11.Insoluble Matter

11.1Scope —The difference between the mass of insoluble matter (including silicon dioxide)and silicon dioxide repre-sents the mass of insoluble matter other than silicon dioxide.The insoluble matter contains the remnants of any clay,siliceous minerals,or other refractory material present in limestone.The elemental components are mainly iron and aluminum which should be removed and added to the main ?ltrate from the SiO 2separation.If the insoluble matter including silica is reported as such and no hydro?uoric acid treatment is indicated,then there is no need to make a recovery of the metals and the insoluble residue may be discarded.11.2Procedure —The insoluble matter left in the crucible after the silica is volatilized with HF may be dissolved by fusing the residue with 2to 3g of sodium carbonate (Na 2CO 3)(See Note 12).Cool the melt and dissolve it in diluted HCl.Add the solution to the ?ltrate from the dehydration and separation of insoluble matter including silicon dioxide (See 8.3.4or 9.3.3).

N OTE 12—Fusion with pyrosulfate is to be avoided because this will introduce undesirable sulfates into the solution.

11.3An alternative fusion can also be made using either lithium metaborate or lithium tetraborate as opposed to using sodium carbonate.

TABLE 3Precision Summary of Classical Test Methods

Section Test Method Average,A %Found

Range,A %Found

Repeatability (R 1,E 173)

Reproducibility (R 2,E 173)

8Insol +SiO 2............(Standard)9Insol +SiO 2 1.4050.09–6.400.1840.351(Optional)10SiO 2

1.1770.03–5.360.1280.14611Insoluble Matter 0.2420.02–0.930.1690.20412Combined Oxides

0.4590.22–1.210.1810.28213Fe 2O 30.1800.05–0.360.0640.18315Al 2O 3

0.2680.10–0.880.1650.22316CaO (Gravimetric)54.4653.4–55.10.558 1.02017CaO (Volumetric)30.5730.4–30.70.371 1.13217CaO (Volumetric)53.8249.6–55.30.1870.29818MgO (Gravimetric)0.8170.19–2.280.1580.21018MgO (Gravimetric)21.3421.1–21.50.652 1.71619

Loss on Ignition

43.73

43.6–43.9

0.158

0.463

Average and range of the limestones

tested.

11.4Calculation—Calculate the percentage of insoluble matter other than silicon dioxide to the nearest0.01%as follows:

Insoluble matter other than SiO2,%5A2B(4) where:

A=insoluble matter including SiO2,%,and

B=SiO2,%.

11.5Precision and Bias:

11.5.1Three laboratories cooperated in testing on four limestone samples and two laboratories cooperated in testing on an additional eight limestone samples thereby obtaining the precision data summarized in Table3.

11.5.2The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

https://www.wendangku.net/doc/e511989145.html,bined Oxides(Iron,Aluminum,Phosphorus,

Titanium,Manganese)

12.1Scope—The combined oxides describe a group of metals that form precipitates with ammonium hydroxide which may then be ignited to their respective oxides.Historically,it has been the practice to report the combined oxides present in limestone samples as a group because it was not always easy or desirable to determine each metal oxide separately.The group of metal oxides consists primarily of the oxides of iron and aluminum,with minor amounts of titanium dioxide(TiO2), phosphorus pentoxide(P2O5),and manganese oxide(Mn3O4) also present.Where separate determinations are preferred,the combined oxides are usually weighed?rst,iron oxide is then assayed separately,and aluminum oxide is?nally determined by calculating the difference between the percent combined oxides and the percent Fe2O3.The other metal oxides are generally assumed to be present in trace amounts and are often disregarded.When necessary,these metals may be analyzed separately and appropriate corrections made in the Al2O3 analysis.

12.2Summary of Test Method—In this test method,alumi-num,iron,titanium,and phosphorus are precipitated from the ?ltrate after SiO2removal,by means of ammonium hydroxide. With care,little if any manganese will be precipitated.The precipitate is ignited and weighed as the combined metal oxides.

12.3Special Solution:

12.3.1Methyl Red Solution(0.2%)—Dissolve2g of me-thyl red indicator with1L of95%ethyl alcohol.

12.4Procedure:

12.4.1To the acid solution from the determination of SiO2(See8.3.4or9.3.3),add hydrochloric acid(HCl)if necessary to ensure a total of10to15mL of HCl.

N OTE13—Sufficient hydrochloric acid must be present before the solution is rendered ammoniacal to prevent the precipitation of magne-sium.

12.4.2If a platinum evaporating dish has been used for the dehydration of SiO2,or a fusion made in the platinum crucible containing the HF-insoluble residue,iron may have been partially reduced.The iron must then be oxidized by adding1mL of saturated bromine water to the?ltrate.Boil the?ltrate to eliminate the excess bromine completely before adding methyl red indicator.

12.4.3Dilute with water to a volume of200to250mL,add

a few drops of methyl red solution,and heat just to boiling. Add NH4OH(1+1)(See Note14)until the color of the solution becomes distinctly yellow,then add1drop in excess (See Note15).Heat the solution containing the precipitate to boiling and boil for50to60s.Remove from heat and allow the precipitate to settle(not more than5min).Filter using medium-textured paper and wash the precipitate two or three times without delay with a hot,2%solution of ammonium chloride(NH4Cl)(See Note16).

N OTE14—The NH

OH used to precipitate the hydroxides must be free

of any dissolved carbon dioxide(CO

N OTE15—At the neutral point,it usually takes1drop of NH

OH (1+1)to change the color of the solution from red to orange and another drop to change the color from orange to yellow.If the color fades during the precipitation or while heating,add more of the indicator.The boiling should not be prolonged as the precipitate may peptize and be difficult to retain on the?lter.The solution should be distinctly yellow when it is

ready to?lter.If it is not,restore the yellow color with more NH

OH (1+1).

N OTE16—Two drops of methyl red indicator solution should be added

to the NH

Cl solution in the wash bottle followed by NH

OH(1+1) added dropwise until the color just changes to yellow.If the color reverts to red at any time due to heating,it should be brought back to yellow by

the addition of a drop of NH

OH(1+1).

12.4.4Set aside the?ltrate and dissolve any precipitate from the paper with40mL hot(1+3)HCl,pouring the hot acid through the paper into the beaker in which the precipita-tion was made.Wash the?lter paper thoroughly with hot HCl (1+19)followed by hot water and reserve the paper.Boil the solution and precipitate the hydroxides with NH4OH as before. The precipitate is?ltered through a fresh piece of medium textured?lter paper and washed four or?ve times(See Note 17)with a hot2%solution of https://www.wendangku.net/doc/e511989145.html,bine?ltrates for Ca and calcium magnesium analysis.

N OTE17—If perchloric acid has been used,the?nal precipitate should be washed at least eight times to remove all traces of perchlorate salts(See 9.3).

12.4.5Place the moist precipitate and the two?lter papers in

a weighed platinum crucible(See Note9),heat slowly until the papers are charred,and?nally ignite to constant weight at1050 to1100°C.Cool in a desiccator and weigh.

12.5Calculation—Calculate the percentage of ammonium hydroxide group(combined oxides)to the nearest0.01%as follows:

Combined oxides,%5~A/C!3100(5) where:

A=mass of the combined oxides,g,and

C=original mass of sample,g.

12.6Precision and Bias:

12.6.1Four laboratories cooperated in testing on four lime-stone samples and three laboratories cooperated in testing on an additional seven limestone samples thereby obtaining the precision data summarized in Table3

12.6.2The user is cautioned to verify by the use of test reference materials,if available,that the bias of this test method is adequate for the contemplated use.

13.Total Iron,Standard Method

13.1Scope—Iron in limestone is usually present as pyrite (FeS2)with occasional occurrences of other discrete iron minerals.The amount present varies according to the location and geological history of the deposit.During lime calcination, most if not all of the iron minerals present in the limestone ore will be converted to iron oxide or sulfate.

13.2Summary of Test Method—In this test method,the total Fe2O3content of the sample is determined from the ignited combined oxides by fusing the oxides with potassium pyrosul-fate and leaching the melt with sulfuric acid.The iron is reduced to the ferrous state with stannous chloride and titrated with a standard solution of potassium dichromate(K2Cr2O7).

13.3Special Solutions:

13.3.1Stannous Chloride Solution(50g/L)—Dissolve5g of SnCl2·2H2O in10mL of HCl and dilute to100mL with water.Add several pieces of mossy tin metal to the bottle to preserve the SnCl2solution.

13.3.2Sodium Diphenylamine Sulfonic Acid Indicator(2 g/L)—Dissolve0.20g sodium diphenylamine sulfonate in100 mL of water.Store in a dark-colored bottle.

13.3.3Mercuric Chloride Solution(5%)—Dissolve5g of HgCl2in100mL of water.

13.3.4Potassium Dichromate,Standard Solution(0.05 N)—Dry pure crystals of K2Cr2O7at110°C,then pulverize and dry at180°C to constant weight.Dissolve2.4518g of pulverized K2Cr2O7in water and dilute to1L.This is a primary standard,1mL=0.0040g Fe2O3.

13.4Procedure:

13.4.1To the combined oxides of iron and aluminum(See Note18)in the platinum crucible,add3to4g of potassium pyrosulfate(K2S2O7).Fuse at low heat until the oxides form a clear melt in the crucible.Cool,break up the button by gently tapping the crucible on the bench,and wash fragments into a small beaker with hot H2SO4(5+95).Add5mL of H2SO4(sp gr1.82)to the contents in the beaker,and heat to dissolve the fused mass.Evaporate the solution to fumes of sulfuric acid and fume strongly for about10min.Cool,add20mL of water, and warm to dissolve the salts.There may be traces of silica appearing at this point,which for most routine work can be ignored.If the analyst prefers to determine it,however,the precipitate can be?ltered,washed,and ignited.The recovered SiO2can then be added to the mass of SiO2previously found and its mass deducted from the gross mass of iron and aluminum reported(See Note18).

N OTE18—When the iron is present in small quantities,it is not always desirable to determine it in the ignited oxides from the0.5-g sample. Under these conditions,the alternative procedure should be used with a larger sample weight.

N OTE19—The recovered SiO

2is usually small,but could be as much

as1to2mg,even after two evaporations.

13.4.2To the sulfuric acid solution,add10mL HCl(1+1) and heat to near boiling.Add dropwise stannous chloride solution(See Note20)until the yellow color of the ferric iron just disappears.Add2or3drops of SnCl2in excess.

N OTE20—If the stannous chloride has little effect and more than5to 10mL are required,it has probably become oxidized to stannic chloride and a fresh supply should be obtained.

13.4.3Cool the mixture and add approximately100mL of cold water.Add10mL of mercuric chloride solution,stir,and allow to stand for3to5min.

N OTE21—A slight,white,silky precipitate should form.If the precipi-tate appears gray or black,it indicates too much SnCl

was added and the analysis must be repeated.

13.4.4Add5mL of H3PO4and3drops of sodium diphe-nylamine sulfonate indicator.

13.4.5Titrate with standard0.05N K2Cr2O7solution add-ing the solution slowly while stirring constantly.The end point is indicated by a change in color from green to deep blue-violet.

13.5Calculation:

Fe2O3,%5~A/C!3B3100(6) where:

A=K2Cr2O7used in titration,mL,

B=0.004(Fe2O3equivalent of K2Cr2O7),and

C=sample,g.

13.6Precision and Bias:

13.6.1Four laboratories cooperated in testing on four lime-stone samples and three laboratories cooperated in testing on an additional seven limestone samples thereby obtaining the precision data summarized in Table3.

13.6.2The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

14.Total Iron by Ortho-Phenanthroline Photometric

Method

14.1Scope—When the iron oxide content is very low,less than0.1%,and an accurate analysis at this low level is required,it is preferable to determine iron using procedures that have better sensitivity than the titrimetric methods.For an accurate determination of minute amounts of iron,the ortho phenanthroline method has proved invaluable.6In general,the method consists of reducing the iron to the ferrous state and then adding a slight excess of1,10phenanthroline,which forms a complex with ferrous iron,giving an orange-pink color.The color intensity is proportional to the iron content of the solution.

14.2Summary of Test Method—The bulk of the iron in the sample is dissolved with HCl,the silica dehydrated and separated by?ltration,and the insoluble matter including SiO2, ignited in a platinum crucible and treated with HF and H2SO4 to expel the SiO2and recover the small amount of iron that may not have dissolved with HCl.The acidi?ed solution is transferred to a volumetric?ask and diluted to volume.The iron is reduced with hydroxylamine hydrochloride and the

6Sandel, E. B.,Colorimetric Determination of Traces of Metals,3rd Ed., Interscience Publications,

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color of the ferrous complex is developed with1,10phenan-throline and compared against a set of iron standards similarly treated.

14.3Special Solutions:

14.3.1Hydroxylamine Hydrochloride(10g/100)—Dissolve 10g of hydroxylamine hydrochloride in100mL of water. Prepare fresh every week.

14.3.2Ammonium Acetate(20g/100)—Dissolve200g in1 L of water.

14.3.31,10(Ortho)Phenanthroline(0.1g/100)—Dissolve 1.0g in1L of hot water.

14.3.4Iron Standard Solution(1mL=1.0mg Fe2O3)—Dissolve0.7000g of pure iron wire by heating gently in20mL of HCl(1+1)and dilute to1L in a volumetric?ask.

14.3.4.1Iron Work Standard Solution(1mL=0.01mg Fe2O3)—Transfer10mL of the iron standard solution to a1L volumetric?ask and dilute to volume with water.

14.3.5Preparation of Calibration Curve—To each of six50 mL volumetric?asks,add,respectively,1,2,4,6,8,and10mL of working iron standard solution.When diluted to volume, each mL of the prepared standard solutions will contain, respectively0.2,0.4,0.8,1.2,1.6,and2.0micrograms Fe2O3.

14.3.5.1Add to each?ask in the following sequence, mixing after each addition,1mL of hydroxylamine hydrochlo-ride solution,5mL of ammonium acetate,and5mL of1,10 phenanthroline.Roll a small piece of congo red paper into a ball and insert it into the volumetric?ask.Add NH4OH(1+1) until the congo red indicator turns bright red,then add1drop of NH4OH(1+1)in excess.Dilute to50mL,mix,and let stand for15to20min.Determine the absorbance of the solution in a spectrophotometer at a wavelength setting of510 nm using water in the reference cell.Prepare a calibration curve by plotting the absorbance versus the concentration of Fe2O3inμg/mL of solution.

14.4Procedure:

14.4.1Weigh1g of the properly prepared sample in10mL HCl(1+1)and evaporate rapidly to dryness.Add50mL of HCl(1+4)and heat to dissolve the salts.Filter the insoluble matter including SiO2through a retentive paper and wash several times with hot water.Reserve the residue.Heat the ?ltrate to boiling.

14.4.2Place the paper containing the insoluble matter from the evaporated HCl solution in a platinum crucible.Char the paper at low heat without in?aming,then ignite at higher heat until the carbon has been completely burned off.Cool,add1 mL H2SO4and10to15mL HF and evaporate to fumes of sulfuric acid.Cool,dilute the contents of the crucible with water,and warm to dissolve salts.Transfer the acidi?ed solution to the main solution containing the bulk of the iron.

14.4.3Transfer the combined solutions to a100mL volu-metric?ask and dilute to volume.Pipet the aliquot containing 0.02to0.10mg Fe2O3into a50mL volumetric?ask.Dilute to about25mL and add in the following sequence,mixing well after each addition:1mL hydroxylamine hydrochloride,5mL ammonium acetate,and5mL of1,10phenanthroline.Roll a small piece of congo red paper into a ball and insert into the volumetric?ask.Add NH4OH(1+1)until the congo red indicator turns a bright red,then add one drop of NH4OH (1+1)in excess.Dilute to50mL,mix and let stand for15to 20min.Determine the absorbance of the solution in a spectrophotometer at a wavelength setting of510nm using water in the reference https://www.wendangku.net/doc/e511989145.html,pare against a set of standards similarly treated.

14.5Calculation:

14.5.1Calculate the%Fe2O3as follows:

%Fe2O35

C3D

W310

(7)

where:

C=concentration of Fe2O3in sample solution,μg/mL (determined from calibration curve),

D=dilution factor,and

W=sample mass,g.

14.6Precision and Bias:

14.6.1The number of laboratories,materials,and determi-nations in this study does not meet the minimum requirements for determining precision prescribed in Practice E691:

Test Methods

C25

Practice E691

Minimum Laboratories26

Materials54

Determinations42

14.6.2The following precision statements are provisional. Within?ve years,additional data will be obtained and pro-cessed which does meet the requirements of Practice E691.

14.6.2.1Precision,characterized by repeatability,Sr and r, and reproducibility,SR and R,has been determined for the following test method and materials to be:

Precision Statement for

Test Method:

%Fe2O3Color

Material Average Sr SR r R

S-11430.03580.00580.02010.01630.0564

S-11450.04800.00530.02140.01480.0599

S-11410.16880.04660.06400.13060.1792

S-11420.20250.01410.06310.03960.1767

S-11440.92520.05620.20960.15740.5870 15.Aluminum Oxide

15.1Scope—Aluminum oxide,for the purpose of this test method,is considered to be the difference between the com-bined oxides and Fe2O3.When phosphorus or titanium are determined,their oxides must also be deducted.

15.2Procedure—Subtract the percent Fe2O3obtained in accordance with Sections5.1.1and5.1.2from the percent combined oxides(See Section5.1).Report the remainder as percent Al2O3.In special cases where P2O5and TiO2need to be reported,a correction for these oxides must be made. 15.3Calculation—Calculate the percent Al2O3as follows:

Al2O3,%5A2B(8) where:

A=combined oxides(Al2O3+Fe2O3),%,and

B=Fe2O3,%.

15.4Precision and Bias:

15.4.1Four laboratories cooperated in testing on four lime-stone samples and three laboratories cooperated in testing on an additional seven limestone samples thereby obtaining the precision data summarized in Table3

.--` ` ` , ` ` , , ` , ` ` , ` , , , , ` ` ` ` ` , , , ` , ` -` -` , , ` , , ` , ` , , ` ---

15.4.2The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

16.Calcium Oxide by Gravimetric Method

16.1Scope—Calcium is separated from magnesium by means of a double precipitation as the oxalate after the determination of the ammonium hydroxide group.The precipi-tate is converted to CaO by ignition and weighed.The gravimetric method should be used when a recovery of aluminum is indicated or when a determination of strontium by gravimetric analysis is required.

16.2Summary of Test Method—Calcium is precipitated with ammonium oxalate(NH4)2C2O4,?ltered,ignited to the oxide,and redissolved with HCl.Any of the NH4OH group of metals that escaped precipitation before may be recovered at this point by the addition of a small amount of NH4OH and boiling.Any precipitate that separates out is assumed to be Al(OH)3and after ignition to Al2O3this amount is added to the mass of Al2O3calculated in16.2.Calcium is precipitated a second time as the oxalate,?ltered,washed,ignited,and weighed as CaO.

16.3Special Solutions:

16.3.1Ammonium Oxalate Solution(saturated)—Dissolve 45g of ammonium oxalate(NH4C2O4)in1L of hot water. When cooled to room temperature the supersaturated solution will partially crystallize out and the supernatant solution will then be saturated with ammonium oxalate.

16.3.2Ammonium Oxalate Wash Solution(1g/L)—Dissolve1g of(NH4)2C2O4in1L of water.

16.4Procedure:

16.4.1Add30mL of HCl(1+1)and20mL of10%oxalic acid to the combined?ltrates from the iron and aluminum hydroxide precipitation and heat the solution to boiling.To the boiling solution,add ammonium hydroxide(1+3)slowly until a precipitate begins to form.At this point,add the ammonium hydroxide still more slowly(dropwise,with a pipet)while stirring continuously until the methyl red just turns yellow.Add 25mL of hot saturated ammonium oxalate solution while stirring.Remove from the heat and let stand until the precipi-tate has settled and the supernatant liquid is clear.Allow to cool for a minimum of1h,and?lter using a retentive paper.Wash the paper and precipitate with?ve10-mL portions of cold, neutral0.1%solution of(NH4)2C2O4(See Note22).Reserve ?ltrate for the magnesium determination.

N OTE22—Hot solutions should be avoided when washing the CaC

precipitate.One litre of hot water will dissolve5mg of CaO.One litre of

cold0.1%(NH

solution will dissolve only0.1mg of CaO.

16.4.2Place the wet?lter and precipitate in a platinum crucible,and char the paper without in?aming at low heat. Increase the heat to burn off all the carbon and ignite at1000°C for about10min.Cool,dissolve the ignited oxide in50mL of dilute HCl(1+4),and dilute to about100mL with water. Add a few drops of methyl red indicator and neutralize with NH4OH till the color of indicator changes to yellow.Heat just to boiling.If a small amount of Al(OH)3separates,?lter it, wash with a hot2%solution of NH4Cl,ignite,weigh,and add this to the mass of Al2O3determined in15.2.

16.4.3Heat the?ltrate to boiling and add slowly,while stirring,35mL of saturated(NH4)2C2O4solution.Digest,?lter, and wash as https://www.wendangku.net/doc/e511989145.html,bine the?ltrate and washing with the ones reserved from the?rst precipitation,and retain for the determination of MgO.Place the?lter in a tared platinum crucible with cover and carefully char the paper without in?aming.Increase the heat to burn off the carbon and ignite the calcium oxide in the covered platinum crucible at1000°C. Cool in a desiccator and weigh as CaO.Repeat the ignition to constant weight avoiding any hydration or carbonation of the lime.

16.5Calculation—Calculate the percent calcium oxide (CaO)as follows:

CaO,%5~M/W!3100(9) where:

M=mass of CaO,g,and

W=mass of sample,g.

16.6Precision and Bias:

16.6.1Two laboratories cooperated in testing on four lime-stone samples and obtained the precision data summarized in Table3.

16.6.2The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

17.Calcium Oxide by Volumetric Method

17.1Scope—This volumetric test method is used mostly for ordinary control work in the plant laboratory,but it is capable of giving exact results,especially with those products that are free of interfering elements.Traces of strontium,barium, magnesium,or oxalate that may be present will also be titrated and calculated as calcium on an equivalence,not weight,basis.

17.2Summary of Test Method—In this test method,the calcium oxalate precipitate is dissolved with dilute sulfuric acid and the liberated oxalic acid is titrated with standard potassium permanganate.The calcium equivalent of the oxalic acid is determined and the grams of CaO calculated.

17.3Special Solutions:

17.3.1Potassium Permanganate,Standard Solution(0.175 N):

17.3.1.1Dissolve 5.64g of potassium permanganate (KMnO4)in1L of water and boil gently for20to30min. Dilute again to1L,cover and allow to age for several days. Filter through puri?ed asbestos or a wad of glass wool,and standardize against the National Institute of Standards and Technology’s standard sample40C of sodium oxalate (Na2C2O4)or equivalent as follows:

17.3.1.2Transfer0.5g of the standard sodium oxalate dried at105°C to a400-mL beaker.Add250mL of diluted H2SO4(5+95)freshly boiled for10to15min and cooled to 2763°C.Stir until the oxalate has dissolved.Add40to42 mL of the standard KMnO4solution at the rate of25to35 mL/min,while stirring slowly.Let stand until the pink color disappears(about60s)(See Note X1.2).

17.3.1.3Heat the contents of the beaker to60°C and complete the titration at this temperature by adding KMnO4 solution until a slight pink color persists for30s.Add the

last --` ` ` , ` ` , , ` , ` ` , ` , , , , ` ` ` ` ` , , , ` , ` -` -` , , ` , , ` , ` , , ` ---

0.5to1mL dropwise,allowing each drop to become decol-orized before the next one is added.

17.3.1.4Determine the exact normality of the KMnO4 solution from the following:

N5W/V30.06701(10) where:

N=normality of KMnO4solution,

W=mass of standard sodium oxalate,

V=KMnO4used to titrate sodium oxalate,mL,and 0.06701=sodium oxalate equivalent to1mL of1N

KMnO4solution,g.

17.3.1.5Determine the CaO equivalent of the KMnO4 solution as follows:

F5N30.02804(11) where:

F=CaO equivalent of the KMnO4solution in grams CaO/mL,

N=normality of KMnO4solution,and

0.02804=CaO equivalent to1mL of1N KMnO4solu-

tion,g.

17.4Procedure:

17.4.1Add30mL of HCl(1+1)and20mL of10%oxalic acid to the combined?ltrates from the iron and aluminum hydroxide precipitation and heat the solution to boiling.To the boiling solution,add ammonium hydroxide(1+3)slowly until a precipitate begins to form.At this point,add the ammonium hydroxide still more slowly(dropwise,with a pipet)while stirring continuously until the methyl red just turns yellow.Add 25mL of hot saturated ammonium oxalate while stirring. Remove from the heat and let stand until the precipitate has settled and the supernatant liquid is clear.Allow to cool and ?lter at the end of1h.Wash the paper with cold water,limiting the total washings to125mL(See Note23).Retain the?ltrate for magnesium.

N OTE23—A Gooch crucible may be used instead of?lter paper to?lter

the CaC

precipitate.

17.4.2With a jet of hot water,wash the precipitate from the paper into the beaker in which the precipitation was made.Fold the paper and leave it adhering to the upper portion of the beaker.Add to the contents of the beaker250mL of hot, diluted H2SO4(1+19)and heat to80to90°C.

17.4.3Titrate with0.175N KMnO4solution until the pink end point is obtained.Drop the folded?lter paper that contained the original precipitate into the liquid and macerate it with a stirring rod;the pink color of the solution will be discharged(See Note24).Finish the titration by adding the KMnO4standard solution dropwise until the end point is again obtained.

N OTE24—There will always be some?ne particles of precipitate imbedded in the pores of the?lter paper which are dissolved by the acid in solution.The?lter paper is not introduced at the beginning of the titration to avoid introduction of traces of organic matter due to the action

of the hot sulfuric acid on the paper;these would consume KMnO

4and

give high results for CaO.

17.5Calculation—Calculate the percentage of CaO in the sample using the CaO equivalent from17.3.1.5as follows:

CaO,%5~V3F!/W3100(12) where:

V=KMnO4solution used in titration,mL,

F=CaO equivalent of KMnO4,and

W=original mass of sample,g.

17.6Precision and Bias:

17.6.1Two laboratories cooperated in testing on twelve limestone samples and obtained the precision data summarized in Table3.

17.6.2The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

18.Magnesium Oxide

18.1Scope—Magnesium oxide in lime and limestone may vary from a few tenths to2%for high-calcium limestone to as much as22%for dolomitic limestone.The pyrophosphate gravimetric method has been used successfully throughout the industry to determine magnesium within this wide range. 18.2Summary of Test Method—In this test method,magne-sium is doubly precipitated as magnesium ammonium phos-phate from the?ltrate after removal of calcium.The precipitate is ignited and weighed as magnesium pyrophosphate (Mg2P2O7).The MgO equivalent is then calculated.

18.3Special Solutions:

18.3.1Ammonium Phosphate,Dibasic Solution(250g/L)—Dissolve250g of dibasic ammonium phosphate ((NH4)2HPO4)in1L of water.

18.3.2Ammonium Hydroxide Wash Solution(5+95)—Dilute50mL of NH4OH with950mL of water and add1or2 mL of HNO3.

18.4Procedure:

18.4.1Add2drops of methyl red indicator to the combined ?ltrates from the determination of calcium,acidify with HCl, and concentrate to about250mL.Add to this solution about10 mL of the(NH4)2HPO4solution,250g/L,and cool the solution to room temperature.Add NH4OH slowly while stirring constantly until the solution is alkaline or the crystalline magnesium ammonium phosphate begins to form;then add about15to20mL of NH4OH in excess and continue stirring for several more minutes.Allow the beaker and precipitate to stand in a cool place overnight.Filter and wash with cold dilute ammonium hydroxide wash solution(5+95).

18.4.2Dissolve the precipitate with hot diluted HCl(1+9) and wash the?lter paper well with hot diluted HCl(1+99). Dilute the solution to100mL,cool to room temperature,and add1mL of the20%solution of(NH4)2HPO4.Precipitate the magnesium ammonium phosphate as before and allow to stand for about2h in a cool place.

18.4.3Filter the precipitate on paper or in a tared Gooch crucible,washing with diluted NH4OH(5+95).If?ltered through a Gooch,place directly in a muffle at400°C and raise heat to1100°C.If?ltration was through paper,place paper and precipitate in a weighed platinum or porcelain crucible.Slowly char the paper without in?aming and carefully burn off

the

resulting carbon (Warning —Extreme caution should be exer-cised during this ignition.Reduction of the phosphate precipi-tate can result if carbon is in contact with it at high tempera-tures.There is also a danger of occluding carbon in the precipitate if ignition is too rapid.).Ignite at 1100°C for 1?2h,cool in desiccator,and weigh as Mg 2P 2O 7(See Note 25).

N OTE 25—For research purposes or in the most exacting types of work,the manganese content of the pyrophosphate residue should be determined and deducted as Mn 2P 2O 7.

18.5Calculation —Calculate the percentage of MgO to the nearest 0.01%as follows:

MgO,%5A 336.2/B

(13)

where:A =Mg 2P 2O 7,g,B =sample,g,and

36.2=molecular ratio of 2MgO to Mg 2P 2O 73100.18.6Precision and Bias :

18.6.1Four laboratories cooperated in testing on three limestone samples and three laboratories cooperated in testing on an additional nine limestone samples thereby obtaining the precision data summarized in Table 3.

18.6.2The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.19.Loss on Ignition

19.1Scope —Loss on ignition (LOI)is the loss in weight expressed as percent of the initial “as received”sample weight obtained after ignition of the sample at 1000°C to constant weight.The loss in weight is due to a release of free moisture,chemically combined “lattice”or “hydroxy”water,CO 2,SO 2,and volatile pyrolytic products of any organic material that may be present.

19.2Summary of Test Method —The tared crucible contain-ing the weighed sample is ignited to constant weight.The loss in weight is the LOI of the sample.

19.3Procedure —Transfer approximately 1g of the sample prepared to pass a 100-mesh (149-μm)U.S.standard sieve to a tare-weighed porcelain or platinum crucible.Cover with a lid and weigh accurately to within 0.1mg.When testing quick-lime,the crucible cover is not required.Also,quicklime may be placed directly into a muffle at 1000°C avoiding preignition.Pre-ignite in a muffle furnace at approximately 400°C for 30min.Then increase muffle temperature to 1000°C 620°C,and maintain at this temperature for a minimum of 20min or until constant mass is obtained.The difference between the original mass of the sample and the ?nal mass represents the loss on ignition.

19.4Calculation —Calculate LOI as follows:

LOI,%5~A 2B !/C 3100

(14)

where:

A =mass of crucible +sample,g,

B =mass of crucible plus sample after ignition,g,and

C =mass of sample,g.19.5Precision and Bias :

19.5.1Fifteen laboratories cooperated in testing on three samples of high calcium limestone to obtain the precision data for percent LOI given in 19.5.2and 19.5.3.

19.5.2The repeatability (Practice E 691[r])was found to be 0.158%LOI.

19.5.3The reproducibility (Practice E 691[R])was found to be 0.463%LOI.

19.5.4The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

20.Free Moisture in Limestone

20.1Scope —For the purpose of this test method,the con-ventional de?nition of “hygroscopic moisture”or “free water”(also known as “free-moisture”)is accepted;that is,the amount of water and any other volatile matter than can be expelled from a sample of the material by drying to constant weight at a temperature slightly above the boiling point of water.

20.2Summary of Test Method —The sample in a container is heated in a drying oven at 115to 120°C constant weight.The loss in weight represents the free moisture.20.3Special Apparatus :

20.3.1Bottle,weighing,low-form,glass-stoppered,or wide-form,large porcelain crucible.

20.4Procedure —Weigh 1g of the prepared sample in the stoppered weighing bottle.Remove the stopper and heat in a drying oven at 115to 120°C for 2h.Quickly stopper,cool in a desiccator,and weigh,lifting the stopper momentarily just before weighing.The use of a similar weighing bottle as a counterpoise carried through all the operations is a desirable procedure unless a single pan balance is used.The loss in weight represents “free moisture”loss at 120°C.

20.5Calculation —Calculate the percent “free moisture”as follows:

Free 2moisture,%5~A 2B !/C 3100

(15)

where:

A =mass of crucible and sample before heating,g,

B =mass of crucible and sample after heating at 120°C,g,

and

C =original mass of sample,g.

20.6Precision and Bias —The precision and bias of this test method have not been determined.

21.Free Moisture in Hydrated Lime

21.1Scope —The free moisture in hydrated lime is that water that is released from the sample at a temperature of 115to 120°C.This distinguishes it from the hydroxyl water that is chemically bound to the lime and which cannot be liberated except at higher temperatures.

21.2Summary of Test Method —Free moisture in hydrated lime is determined by aspirating a slow stream of CO 2-free air over the sample in a container placed inside a 115to 120°C oven.The loss in weight of the sample is equal to the free moisture of the hydrated lime.21.3Special Apparatus :

21.3.1Sample Flask E,illustrated in Fig.1,consists of a 50-mL ?at-bottom,glass-stoppered ?ask,supplied with a ground glass joint and solid ground glass

stopper.

--```,``,,`,``,`,,,,`````,,,`,`-`-`,,`,,`,`,,`---

21.3.1.1The ?ask shall be ?tted with an interchangeable hollow ground-glass stopper,equipped with two glass entry tubes for conducting the dry air over the sample.

21.3.2Purifying Train (See Fig.1),located outside the oven F for conducting the dry air over the samples,shall consist of a series of scrubbers and absorption bulbs to remove CO 2and moisture from the air.The apparatus are arranged in the following order starting from the air source:

21.3.2.1Soda-Lime Tower A,at the air inlet to remove CO 2from the air.

21.3.2.2Bottle B,containing lime water to show when the soda lime is exhausted.

21.3.2.3Fleming Jar C,containing sulfuric acid to remove water from the air.

21.3.2.4Absorption Bulb D,?lled with Anhydrone (magne-sium perchlorate)to complete the drying of the air.21.3.2.5Sample Flask E.21.3.2.6Drying Oven F .

21.3.2.7Absorption Bulb G,also ?lled with Anhydrone and located on the exit side of the sample bulb as a protective barrier against atmospheric moisture.

21.4Procedure —Weigh 2.5to 3g of the prepared sample,and using glazed paper folded in the shape of a funnel,transfer it rapidly into the previously weighed bottle and immediately restopper it.Insert the bottle into the 120°C oven and quickly exchange stoppers.Connect the sample bottle to the purifying train by means of ?exible tubing and pass a slow current of dry CO 2-free air through the apparatus for 2h.Disconnect the sample bottle from the train,remove it from the oven with another quick exchange of stoppers,and place it in a desiccator to cool.When cool,remove it to the balance case for several minutes before weighing it,and just before weighing,lift the stopper slightly for an instant to relieve any vacuum that may exist in the bottle.The loss in weight of the sample represents “free moisture”loss as 120°https://www.wendangku.net/doc/e511989145.html,e a bottle similar to the one containing the sample as a counterpoise in all weighings unless a single-pan balance is used.

21.5Calculation —Calculate the percent “free moisture”in the sample as follows:

Free moisture,%5~A 2B !/C 3100

(16)

where:

A =mass of sample ?ask +sample,g,

B =mass of sample ?ask after drying,g,and

C =mass of sample,g.

21.6Precision and Bias —The precision and bias of this test method have not been determined.

22.Carbon Dioxide by Standard Method

22.1Scope —Carbon dioxide in limestone is sometimes determined to verify the presence of carbonates other than calcium or magnesium.These may include carbonates of iron,manganese,and occasionally traces of other substances.Samples of lime and hydrated lime are analyzed for CO 2to check for the presence of carbonates,most of which are there as uncalcined limestone.

22.2Summary of Test Method —The sample is decomposed with HCl and the liberated CO 2is passed through a series of scrubbers to remove water and sul?des.The CO 2is absorbed with Ascarite,a special sodium hydroxide absorbent,and the gain in weight of the absorbtion tube is determined and calculated as percent CO 2.22.3Special Apparatus :

22.3.1The apparatus illustrated in Fig.2consists of the following:

22.3.1.1Purifying Jar A,Fleming,containing sulfuric acid.22.3.1.2Drying Tube B,U-shaped with side arms and glass stoppers.Side arms are shaped to hold rubber tubing.Contains Anhydrone on left side and Ascarite on right side.

22.3.1.3Erlenmeyer Flask C,250-mL,24/40ground-glass joint.

22.3.1.4Separatory Funnel D,with ground-glass stopper and interchangeable hollow ground-glass joint.A delivery tube bent at the end extends into the sample ?ask about 1?2in.from the https://www.wendangku.net/doc/e511989145.html,ed to introduce acid into ?ask.22.3.1.5Condenser E.

22.3.1.6Gas-Washing Bottle F ,250-mL,with fritted disk containing distilled water to retain most of the acid volatilized from the alkalimeter.

22.3.1.7U-Tube G,containing mossy zinc to remove the last traces of

HCl.

A Soda-Lime Tower at inlet to remove CO 2.

B Bottle containing lime water to show when soda lime tower is exhausted.

C Fleming jar containing sulfuric acid to remove water from air.

D Absorption bulb ?lled with Anhydrone (Magnesium Perchlorate)to complete drying of air.

E 50-mL sample ?ask.

F Drying oven operating at 110°C.

G Absorption bulb ?lled with Anhydrone to prevent moisture backup into sample.

FIG.1Apparatus for Free Moisture in Hydrated

Lime

--```,``,,`,``,`,,,,`````,,,`,`-`-`,,`,,`,`,,`---

22.3.1.8Gas-Washing Bottle H,250-mL,with fritted disk,containing concentrated H 2SO 4and trap I,to remove any SO 3mist that may have been carried over.

22.3.1.9Absorption Bulb J,containing Anhydrone to re-move last traces of water vapor.

22.3.1.10CO 2Absorption Bulb,containing Ascarite ?lled as follows:On the bottom of the bulb,place a layer of glass wool extending above the bottom outlet and on top of this a layer of Anhydrone about 3?8in.thick;immediately above this is placed another layer of glass wool,and Ascarite is then added to almost ?ll the bulb.A top layer of Anhydrone about 3?8in.thick is placed on top of the Ascarite and topped off with a covering of glass wool.

22.3.1.11U-Guard Tube L,?lled with Anhydrone in left side and Ascarite in right side.

22.3.1.12Purifying Jar M,Fleming,containing H 2SO 4.22.4Procedure :

22.4.1Weigh an indicated amount of prepared sample,0.5g for limestone and 5g for lime or hydrated lime,and transfer to the 250-mL Erlenmeyer ?ask.Connect the sample ?ask to apparatus as shown in the diagram (See Fig.2).Purge the system free of carbon dioxide by passing a current of CO 2-free air through the apparatus for 10to 15min.

22.4.2Weigh the absorption bulb and attach it to the train.Remove the glass stopper from separatory funnel,place 50mL of dilute HCl (1+1)in the separatory funnel (D )and replace the stopper with the interchangeable hollow ground-glass joint through which passes a tube for admitting puri?ed air.Open the stopcock of the separatory funnel and admit air through the top of the funnel to force the hydrochloric acid into the Erlenmeyer ?ask (C ).

22.4.3Start cold water circulating through the condenser (E )and,with CO 2-free air passing at a moderate rate through

the absorption train,place a small hot plate or gas burner under the sample ?ask and boil for about 2min.Remove the hot plate and continue the ?ow of puri?ed air at about three bubbles per second for 30min to sweep the apparatus free of CO 2.Close the absorption bulb,disconnect it from the train and weigh,opening the stopper momentarily to equalize the https://www.wendangku.net/doc/e511989145.html,e a second absorption bulb as counterpoise in all weighings unless a single pan balance is used.

22.5Calculation —Calculate the percent CO 2as follows:

CO 2,%5~A 2B !/C 3100

(17)

where:

A =mass of absorption bulb +CO 2,g,

B =mass of absorption bulb before the run,g,and

C =mass of sample,g.

22.6Precision and Bias —The precision and bias of this test method have not been determined.23.Sulfur Trioxide

23.1Scope —This test method will determine sulfur com-pounds,mostly present as sulfates in lime and limestone,that are soluble in dilute HCl.Iron pyrites and other sul?des will not be included because they will either be volatilized as H 2S or not react at all with the acid.

23.2Summary of Test Method —In this test method,sulfate is precipitated from an acid solution of the lime or limestone with barium chloride (BaCl 2)and the SO 3equivalent is calculated.

23.3Special Solution :

23.3.1Barium Chloride Solution (100g/L)—Dissolve 100g of barium chloride (BaCl 2·2H 2O)in 1L of

water.

A Purifying jar,Fleming,containing concentrated H 2SO 4.

B Drying tube,U-shaped,Ascarite in right side,Anhydrone in left side.

C Erlenmeyer ?ask,250-mL,24/40glass joint.

D Separatory funnel.

E Condenser.

F Gas-washing bottle,250-mL with fritted disk,containing water to retain most of the acid volatilized from the alkalimeter.

G U-tube containing mossy zinc to remove the last traces of HCl.

H Gas-washing bottle,250-mL with fritted disk,containing concentrated H 2SO 4.I Trap.

J Absorption bulb containing Anydrone.K CO 2absorption bulb containing Ascarite.

L U-guard tube with Anhydrone in left side and Ascarite in right side.M Purifying jar,Fleming,containing concentrated H 2SO 4.

FIG.2Apparatus for Carbon Dioxide by Standard

Method

--```,``,,`,``,`,,,,`````,,,`,`-`-`,,`,,`,`,,`---

23.4Procedure—Select and weigh the prepared sample into a250-mL beaker containing50mL of cold water in accordance with the following:

Expected SO3Range,%Sample Weight,g

0.001to0.50010.00

0.500to2.50 5.00

2.50to12.5 2.00

Stir until all lumps are broken and the lighter particles are in suspension.Add50mL of diluted HCl(1+1)and heat until the reaction has stopped and decomposition is complete.Digest for several minutes at a temperature just below boiling.Add a few drops of methyl red indicator and render the solution alkaline(yellow color)with NH4OH(1+1).Heat the solution to boiling.Filter through a medium-textured paper and wash the residue thoroughly with hot water.Dilute the?ltrate to250 mL,add5mL of HCl(1+1),heat to boiling,and add slowly 10mL of hot BaCl2solution.Continue the boiling until the precipitate is well formed,stir well,and allow to stand overnight at room temperature.Take care to keep the volume of solution between225and250mL,and add water for this purpose if necessary.Filter through a retentive paper and wash the precipitate with hot water.Place the paper and contents in a weighed platinum crucible,and slowly char the paper without ?aming.Burn off all the carbon,ignite in a muffle at1000°C, cool in a desiccator,and weigh.

23.5Calculation—Calculate the percentage of SO3to the nearest0.001as follows:

SO3,%5A30.343/W3100(18) where:

A=mass of BaSO4,g,

W=mass of sample,g,and

0.343=molecular ratio of SO3to BaSO4.

23.6Precision and Bias:

23.6.1Six laboratories cooperated in testing on four samples of limestone and lime materials covering the range from0.04to5.15%SO3to obtain the precision data given in 23.6.2and23.6.3.

23.6.2The repeatability(Practice E173R1)was found to be (0.135%SO3per weight in grams of sample analyzed). 23.6.3The reproducibility(Practice E173R2)was found to be(0.271%SO3per weight in grams of sample analyzed).

23.6.4The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

24.Total Sulfur by Sodium Carbonate Fusion

24.1Scope—Sulfur in limestone is chie?y,if not wholly, present as sul?de,usually as pyrite.If the total sulfur obtained in the following test method is in excess of that present as soluble sulfate,the difference can be assumed to be present as iron disul?de.

24.2Summary of Test Method—The sample is fused with sodium carbonate and the ignited mass is leached in water and dissolved with HCl.The solution is made ammoniacal and the hydroxide precipitate is?ltered.The sulfur in the?ltrate is precipitated with a10%solution of barium chloride.The precipitate is ignited and weighed as barium sulfate(BaSO4) and the SO3equivalent is calculated.

24.3Procedure:

24.3.1Select and weigh the prepared sample into a porce-lain crucible in accordance with the following:

Expected S Range,%Sample Weight,g Na2CO3Weight,g

0.001to0.2010.00 5.00

0.200to1.00 5.00 2.50

1.00to5.00

2.00 1.00

Add the indicated amount of Na2CO3and mix well.Heat in a muffle at600°C for15min.Increase the heat50°C every15 min until1000°C is reached and maintain at this temperature for15min.(See Note26).Cool,place the crucible and cover in a400-mL beaker,and cover with hot water.Add10mL bromine water(See Note27)and then add sufficient HCl (1+1)to make the solution slightly acid to methyl red.Boil until solution is complete and all bromine has been expelled. Remove the crucible and wash with hot water.

N OTE26—Since not enough?ux is used to produce more than a sintering,the air entering the crucible after the bulk of the carbon dioxide has been released effects very speedy oxidation in the porous mass.

N OTE27—It has been found that10mL of30%hydrogen peroxide (H

)may be substituted for the bromine water to accomplish oxidation without affecting the analytical result.

24.3.2Add a few drops of methyl red indicator and render the solution alkaline with NH4OH(1+1).Heat the solution to boiling,?lter using a retentive paper and wash with hot water. To the?ltrate add5mL of HCl(1+1),adjust the volume to about250mL,and bring the solution to boiling.To the boiling solution,add10mL of hot BaCl2solution,slowly and with stirring.Allow to stand overnight.Filter through a retentive paper and wash the precipitate with hot water.Place paper and contents in a weighed platinum crucible and slowly char the paper without?aming.Burn off the carbon and ignite in a muffle at1000°C for1h.Cool in a desiccator and weigh as BaSO4.

24.4Calculation—Calculate the percentage of sulfur to the nearest0.001as follows:

S,%5A313.73/W(19) where:

A=mass of BaSO4,g,

W=sample,g,and

13.73=mass of molecular ratio of S to BaSO43100. 24.5Precision and Bias:

24.5.1Six laboratories cooperated in testing on four samples of limestone and lime materials covering the range from0.021to2.15%sulfur to obtain the precision data given in24.5.2and24.5.3.

24.5.2The repeatability(Practice E173R1)was found to be (0.065%S per weight in grams of sample analyzed).

24.5.3The reproducibility(Practice E173R2)was found to be(0.094%S per weight in grams of sample analyzed). 24.5.4The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

25.Total Sulfur by the Combustion-Iodate Titration

Method

25.1Scope—This test method covers the determination of sulfur in concentration from0.005to1%.At the

combustion --` ` ` , ` ` , , ` , ` ` , ` , , , , ` ` ` ` ` , , , ` , ` -` -` , , ` , , ` , ` , , ` ---

temperature of approximately1650°C,complete combustion of the sulfur in the sample will take place regardless of sulfur form or sample matrix.

25.2Summary of Test Method—A major portion of the sulfur in various types of lime and limestone samples is converted to oxides of sulfur,primarily sulfur dioxide(SO2), by combustion in a stream of oxygen at the elevated tempera-ture of a high-frequency induction furnace.During the com-bustion,the SO2is absorbed in an acidi?ed starch-iodine solution and titrated with potassium iodate.The latter is standardized against limestone standard samples of known sulfur content to compensate for characteristics of a given apparatus and for day-to-day variation in the percentage of sulfur recovered as https://www.wendangku.net/doc/e511989145.html,pensation is also made for the blank due to accelerators and crucibles.

25.3Apparatus:

25.3.1Induction Furnace—The induction furnace shall be supplied with a rheostat used to control the power input to the reduction coil that will avoid heating some types of samples too rapidly during the early stages of combustion.The train of the induction furnace shall include an oxygen puri?er,de-scribed in25.3.3.

25.3.2Automatic Titrator—This apparatus shall consist of an absorption and titration vessel of appropriate volume and contain an inlet bubbler tube for the sulfur gases with a?oat valve to prevent back?ow of liquid when the sample is starting to consume oxygen.The vessel must be shaped to effect complete absorption of SO2in a small volume of solution.The titrator comes equipped with a buret that should be approxi-mately10mL in capacity marked with200divisions.The automatic titrator utilizes a photoelectric cell to activate a titrator inlet valve that allows the titration to proceed without the presence of an operator.

25.3.3Oxygen Puri?ers—Reagent-grade oxygen from a commercial tank is passed through a suitable two-stage reduc-tion valve to provide an even and adequate?ow of oxygen through a purifying train consisting of a sulfuric acid tower,an absorption bulb containing20to30-mesh inert base impreg-nated with NaOH,and another absorption bulb containing anhydrous magnesium perchlorate Mg(ClO4).A?owmeter precedes the induction furnace assembly.

25.3.4Combustion Crucibles—The crucibles for use with the induction furnace must be of adequate thickness to retain the molten slag and have a sulfur blank as low and consistent as possible.The crucibles for use in the induction furnace must have adequate capacity and may be provided with suitable covers.

25.3.5Glass Accelerator Scoop.

25.3.6Starch Dispenser—A plastic bottle with a device for dispensing a few millilitres of starch solution at a time. 25.3.7Timer,having a0to15-min range in1?4-min intervals. Turns off the furnace at end of preset time and automatically resets.

25.3.8Loading Funnel—Three-legged funnel that?ts over the crucible and simpli?es addition of sample.

25.4Reagents:

25.4.1Copper(Low-Sulfur)Ring Accelerator.

25.4.2Iron(Low-Sulfur)Accelerator—Iron chips.(For samples containing very low percentages of sulfur,the use of iron powder is recommended because of its low blank.) 25.4.3Tin Metal(Low-Sulfur)Accelerator,granular.

25.4.4Potassium Iodate(KIO3)Crystal.

25.4.5Potassium Iodide(KI)Crystal.

25.4.6Starch,soluble.

25.5Special Solutions:

25.5.1Potassium Iodate,standard solutions.

25.5.1.1KIO3Standard Solution A—Dissolve0.2227g KIO3in900mL of water containing1g sodium hydroxide (NaOH)and dilute to1L.For a0.500-g sample,the buret reads directly in percent sulfur.

25.5.1.2Starch-Iodide Solution—Transfer2g of soluble starch(for example,Arrowroot)to a50-mL beaker,add a few millilitres of water,and stir into a smooth paste.Slowly add starch to500mL of distilled water while stirring.Add4g of NaOH and continue stirring the solution until the appearance changes from cloudy to translucent.Add6g of potassium iodide(KI),stir until the KI is dissolved,and dilute to1L. N OTE28—Discard any starch solution that imparts a red tinge to the blue color when titrating.

25.6Calibration—This test method and instrument should be standardized by using a limestone sample of known sulfur content as determined by the Total Sulfur Method by Sodium Carbonate Fusion,Section24.The Leco instrument,in addi-tion,may be standardized daily by running limestone reference materials whose sulfur content,as determined by the Total Sulfur Method,ranges from0.02to0.05%.The limestone standards are run to determine the day-to-day variations in the test method and to verify that the electronics in the Leco are working properly.

25.6.1It has been found through round robin studies that the practice of pre-igniting samples at1000°C causes erratic recovery of sulfur.This practice should not be used.

25.7Procedure:

25.7.1Allow15min for the electronics in the furnace assembly and titrator to warm up.

25.7.2Set the grid-current tap switch to low,medium,or high position.Determine the position on a test run,with the sample and accelerators that will give a complete combustion at approximately400mA as indicated on the plate current ammeter.

25.7.3Set the automatic timer to the estimated time re-quired to evolve the sulfur in the sample completely,as

follows:

Sample Time,Min

Quicklime8

Hydrated Lime10

Limestone12

25.7.4Weigh the sample and brush carefully into the combustion crucible using the loading funnel.The correct sample weight is determined by the estimated sulfur content of the sample as follows:

Sulfur%Sample Weight(g)

0.0010.500

25.7.5The choice of accelerators is left to the discretion of the user,as each furnace will burn differently in accordance with type and amount used.Generally,the more accelerator used,the greater the furnace temperature.Tin metal,iron chip, iron powder,and copper ring have been found to be suitable materials.Porous covers should be used to prevent splattering of the hot?ux and damage to the combustion tube.Do not re-use crucibles or covers.

25.7.6Run a blank determination before each series(of sulfur determinations)using a crucible that contains all the accelerators but no sample.

25.7.7Place the crucible and sample on the pedestal and lift into position in the combustion tube.

25.7.8With the oxygen?ow at1L/min,close stopcock on bottom of titration vessel,and add the HCl to the middle of the bell-shaped portion of the titration vessel.Always?ll to the same level.

25.7.8.1Add one measure of starch solution to the titration vessel.Fill the iodate buret.

25.7.9Turn the double throw switch on the titrator to the end-point position(down).Slowly rotate the end-point control in a clockwise direction until it has added KIO3in the amount to give a solid medium blue color.After the indicator light(for solenoid valve)has stopped blinking,place the switch in the neutral position and?ll the KIO3buret again.Turn the switch to the titrate position.

25.7.10Turn on the power of the high-frequency furnace. The temperature will rise in the crucible as indicated by the plate current ammeter on the induction furnace that must indicate a reading of at least400mA before complete com-bustion of sulfur can take place.

25.7.11As sulfur dioxide is given off,the unit will begin titrating automatically.The titration is?nished when the indicator light stops blinking for a period of time,or the iodate in the buret stops falling over a period of time.

25.7.12Inspect the crucible for a proper burn.A rough, bumpy surface or appearance of non-combustion indicates that the furnace temperature was too low.Sticking of the porous cover to the crucible indicates that the furnace temperature may have been too hot.Both conditions indicate poor sulfur recovery and may be helped by a slight change in accelerator amounts.

25.8Calculation:

25.8.1Calculation of Furnace Factor(F)

F5R

~A2B!/~W32!

(20) where:

A=buret reading as%Sulfur(S),

B=buret reading for Blank determination,

R=%Sulfur(by Sodium Carbonate Fusion Method)of the reference material,and

W=weight of sample,g.

25.8.2Calculate the percentage of sulfur in the sample by using furnace factor F.

%S5F3

A2B

W32(21) where:

A=buret reading as%Sulfur(S),

B=buret reading for Blank determination,

F=furnace factor,and

W=weight of sample,g.

25.9Precision and Bias:

25.9.1Nine laboratories cooperated in testing on three samples of high-calcium limestone to obtain the precision data for%sulfur given in25.9.2and25.9.3.

25.9.2The repeatability(Practice E691[r])was found to be 0.0070%sulfur.

25.9.3The reproducibility(Practice E691[R])was found to be0.0120%sulfur.

25.9.4The user is cautioned to verify by the use of reference materials,if available,that the bias of this test method is adequate for the contemplated use.

26.Phosphorus by Molybdovanadate Method

26.1Scope—This method is suitable for the determination of small amounts of phosphorous in lime and limestone samples.The procedure is based on the fact that phosphorous in its ortho form will combine with ammonium molybdovana-date to yield a yellow color that can be measured spectropho-tometrically.Total phosphate is determined after a strong oxidation decomposition with perchloric acid.

26.2Summary of Test Method—The sample is decomposed with perchloric acid,the solution?ltered,SiO2expelled,and the insoluble residue fused with Na2CO3.Ammonium molyb-dovanadate which is then added reacts with the phosphorous in solution to form the heteropoly phosphomolybdovanadate complex.The absorbance of the solution is measured with a photometer at430nm and compared against standards simi-larly treated.

26.3Special Solutions:

26.3.1Phosphorous Standard Stock Solution(0.5mg P/mL)—Weigh1.0983g of potassium dihyrogen phosphate, KH2PO4,into a250-mL beaker and dampen with about5to10 mL of water.Add10mL HNO3and25mL HClO4(See Note 29),heat on a hot plate,and evaporate to heavy fumes of HClO4.Cover and boil until the solution is colorless or slightly yellow(10to15min).Cool the solution,transfer to a500-mL volumetric?ask,dilute to volume,and mix.Store in a borosilicate or plastic bottle with a screw cap.

26.3.2Phosphorous Working Standard(0.05mg P/mL)—Dilute50mL of stock solution26.3.1to500mL with distilled water.Store in a Pyrex or plastic bottle with screw cap. 26.3.3Ammonium Molybdovanadate Solution:

26.3.3.1Dissolve1.25g of ammonium metavanadate in400 mL of1+1nitric acid in a1L volumetric

?ask.--` ` ` , ` ` , , ` , ` ` , ` , , , , ` ` ` ` ` , , , ` , ` -` -` , , ` , , ` , ` , , ` ---

26.3.3.2Dissolve50g of ammonium molybdate in400mL of distilled water.

26.3.3.3Pour solution from26.3.4.2into solution26.3.4.1, mix,and dilute to volume with distilled water.

26.4Preparation of Standard Curve:

26.4.1To each of seven individual50mL volumetric?asks, add with a buret0,1,2,4,6,10,and14mL of phosphorous working standard solution corresponding to0,0.05,0.10,0.20, 0.30,0.50,and0.70mg of phosphorous,respectively.

26.4.2Add1mL of perchloric acid and dilute to about20 mL with water.Add10mL of the molybdovanadate solution, swirling the contents of the?ask during the addition.Dilute to volume with distilled water,mix well,and allow to stand for10 min.The prepared standard solutions will contain0(blank), 1.0,2.0,4.0,6.0,10.0,and14.0micrograms(μg)P/mL. 26.4.3Determine the absorbance of each standard solution in the spectrophotometer at a wavelength of430nm using the blank standard as the reference solution.Prepare a calibration curve by plotting absorbance versus concentration of phospho-rous inμg/mL.

26.5Procedure:

26.5.1Weigh 5.0g of prepared sample into a250-mL beaker and dampen with about5to10mL of water.Add10mL HNO3and25mL HClO4(See Note29),heat on hot plate,and evaporate to heavy fumes of HClO4.Cover and boil until solution is colorless or slightly yellow(10to15min).Cool slightly and add50mL H2O.Filter through retentive?lter paper and wash thoroughly with hot H2O(See Note30). Reserve?ltrate.

N OTE29—If a special perchloric acid hood is not available,the use of

perchloric may be omitted.Instead,add10mL HNO

3and evaporate to

dryness.Take up salts with5mL HCl,break up residue,and again

evaporate to dryness.Boil up with1mL of HNO

3and20mL of water,and

?lter,etc.

N OTE30—The?lter paper and silica residue must be washed free of perchlorate salts to prevent small explosions from occurring in the crucible when the?lter paper is charred and ignited.

26.5.2Place paper and contents in a platinum crucible and heat gently with a low?ame until paper chars.Ignite at a higher temperature until ash is white.Cool,add2drops of H2SO4(1+1)and10to15mL HF.Evaporate cautiously to dryness and heat in a muffle at1000°C for2min(See Note 31).Fuse residue with0.5g of Na2CO3,cool,add5mL H2O and1mL HClO4and warm to https://www.wendangku.net/doc/e511989145.html,bine the?ltrates and transfer to a100mL volumetric?ask.Dilute to volume and mix.

N OTE31—The treatment of the residue with HF and H

2SO

may be

omitted if the SiO

in the sample is low,<3%.

26.5.3Pipet25mL of solution into a50mL-volumetric ?ask and add10mL ammonium molydovanadate solution, dilute to volume and mix well.Allow to stand30min and measure the absorbance at430nm using the blank standard solution in the reference https://www.wendangku.net/doc/e511989145.html,pare against a set of standards similarly treated.

26.6Calculation:

26.6.1Calculate%P2O5as follows:

%P2O55C3D32.2913

W3104

(22)

where:

C=concentration of P in sample solution,μg/mL deter-

mined from calibration curve,

D=dilution factor,and

W=g of sample.

26.7Precision and Bias:

26.7.1The number of laboratories,materials,and determi-

nations in this study does not meet the minimum requirements

for determining precision prescribed in Practice E691:

Test Methods

C25

Practice E691

Minimum

Laboratories36

Materials54

Determinations42

26.7.2The following precision statements are provisional.

Within?ve years,additional data will be obtained and pro-

cessed which does meet the requirements of Practice E691.

26.7.2.1Precision,characterized by repeatability,Sr and r,

and reproducibility,SR and R,has been determined for the

following test method and materials to be:

Precision Statement for

Test Method:

%P2O5Color

Material Average Sr SR r R

S-11450.00310.00100.00170.00290.0046

S-11420.00910.00190.00310.00530.0087

S-11410.02210.00140.00430.00400.0122

S-11440.06570.00630.01440.01750.0404

S-11430.13530.00770.01470.02150.0413

27.Manganese by the Periodate(Photometric)Method

27.1Scope—In this method,periodate is the oxidizing

agent used to convert manganous into permanganate ion whose

color can then be read in a photometer at a wavelength of545

nm.This method is capable of determining small amounts of

Mn as low as10ppm.

27.2Summary of Test Method—The same sample solution

prepared in the determinations of phosphorous by molybdo-

vanadate(See26.5.1to26.5.2)can be used for the determina-

tion of manganese by periodate.The acid solution is oxidized

to permanganate by potassium periodate.Photometric mea-

surement is made at545nm.

27.3Special Solutions:

27.3.1Manganese Standard Solution(1mL to50μg Mn)—

Dissolve0.0500g pure manganese(Mn)metal in20mL

H2SO4(1+9)and dilute to1L with water.

27.3.2Nitric-Phosphoric Acid Mixture—Add800mL

HNO3and200mL H3PO4to400mL of H2O and dilute to2L.

27.4Preparation of Calibration Curve:

27.4.1Transfer0,1,2,3,5and10mL of manganese

standard solution to six150mL beakers,respectively.Add25

mL of acid mixture to each and heat but do not boil.While

heating,add potassium periodate(KIO3)crystals,a few milli-

grams at a time(about0.3g total),until the permanganic color

is fully developed.Keep solution near boiling for10min after

color develops;the total heating period should last about30

min.

27.4.2Allow to cool,transfer to a50-mL volumetric?ask,

dilute to volume and mix.Read absorbance at545nm using the

“0”standard(blank)in the reference cell and construct a

calibration curve by plotting absorbance versus concentration

of Mn in

μg/mL.

27.5Procedure:

27.5.1Weigh 2.0g of prepared sample into a250-mL beaker and dampen with about5to10mL of water.Add10mL HNO3and20mL HClO4(See Note32),heat on hot plate,and evaporate to heavy fumes of HClO4.Cover and boil until solution is colorless or slightly yellow(10to15min).Cool slightly and add50mL H2O.Filter through retentive?lter paper and wash thoroughly with hot H2O(See Note30). Reserve?ltrate.

N OTE32—If a special perchloric hood is not available,omit the use of

HClO

4.Instead,evaporate to dryness twice with nitric acid and?nally boil

with10mL HNO

3and50mL H

27.5.2Transfer paper and contents to a platinum crucible and heat until paper chars.Ignite at a higher temperature until ash is white.Cool,expel SiO2with HF and H2SO4,evaporate to dryness(See Note31)and fuse residue with Na2CO3.Cool, add10mL H2O and2mL HNO3and warm to dissolve. Combine solution with?ltrate reserved in27.5.1and transfer to a100mL volumetric?ask.Dilute to volume and mix.

27.5.3Transfer an aliquot containing<500μg Mn to a150 mL beaker.Add25mL of acid mixture,heat to near boiling and develop the permanganate color by small additions of KIO3as directed in27.4.1.Cool the solution,transfer to a50mL volumetric?ask,dilute to volume and mix.

27.5.4Record the absorbance at545nm using the blank standard solution in reference cell as in preparation of standard curve,and compare against a set of standards similarly treated.

27.6Calculation:

27.6.1Calculate the percent Mn as follows:

%Mn5C3D

W3104

(23)

where:

C=concentration of Mn in sample solutionμg/mL deter-mined from calibration curve,

D=dilution factor,and

W=g of sample.

27.7Precision and Bias:

27.7.1The number of laboratories,materials,and determi-nations in this study does not meet the minimum requirements for determining precision prescribed in Practice E691:

Test Methods

C25Practice E691 Minimum

Laboratories46

Materials54

Determinations42

27.7.2The following precision statements are provisional. Within?ve years,additional data will be obtained and pro-cessed which does meet the requirements of Practice E691.

27.7.2.1Precision,characterized by repeatability,Sr and r, and reproducibility,SR and R,has been determined for the following test method and materials to be:

Precision Statement

for Test Method:

%Mn Color

Material Average Sr SR r R

S-11450.00110.00040.00050.00110.0014

S-11430.00250.00050.00070.00140.0020

S-11420.01470.00100.00100.00280.0028

S-11410.02710.00120.00240.00340.0066

S-11440.10960.00720.01080.02000.030428.Available Lime Index

28.1Scope—The available lime index of high-calcium quicklime and hydrated lime designates those constituents that enter into the reaction under the conditions of this speci?ed test method,otherwise known as the“rapid sugar test method.”The interpretation of results obtained by this test method shall be restricted by this de?nition.

28.2Summary of Test Method—The sample is slaked and dispersed with water.The lime is solubilized by reaction with sugar to form calcium sucrate which is then determined by titration against standard acid using phenolphthalein as the indicator.

28.3Special Solutions:

28.3.1Hydrochloric Acid,Standard(1.000N)—Prepare a solution by diluting83mL of HCl to1L with CO2-free water. Standardization of sock solution should be performed on a regular basis at a minimum of once per month.For precision and bias information on standardization with Na2CO3or Tris-(Hydroxymethyl)Amino-Methane see Practice E200. 28.3.2Standardization of HCl with Na2CO3:

28.3.2.1Transfer approximately20g of primary standard anhydrous sodium carbonate(Na2CO3)to a platinum dish or crucible,and dry at250°C for4h.Cool in a desiccator. 28.3.2.2Weigh accurately4.4g to the nearest0.1mg of the dried Na2CO3and transfer to a500-mL?ask.Add50mL of CO2-free water,swirl to dissolve the carbonate,and add two drops of a0.1%solution of methyl red in alcohol.Titrate with the HCl solution to the?rst appearance of a red color,and boil the solution carefully,until the color is discharged(See Note 29).Cool to room temperature,and continue the titration, alternating the addition of HCl solution and the boiling and cooling to the?rst appearance of a faint red color that is not discharged on further heating.

28.3.2.3Calculation—Calculate normality as follows:

A5~B318.87!/C(24) where:

A=normality of the HCl solution,

B=Na2CO3used,g,and

C=HCl solution consumed,mL.

N OTE33—This titration can also be performed potentiometrically with the aid of a glass electrode and a calomel electrode.

28.3.3Standardization of HCl with TRIS(THAM)—[Tris-(Hydroxymethyl)Amino-Methane]:

28.3.3.1Transfer an appropriate amount of primary stan-dard tris-(hydroxymethyl)amino-methane to suitable dish or crucible and dry in a vacuum at70°C for24h(refer to Practice E200).As an alternative,Tris can also be dried at105°C(65°C)for2h in a regular laboratory drying oven.Cool in a desiccator to room temperature.

28.3.3.2Preparation of Mixed Indicator—Mix100mg of Bromocresol Green with2mL0.1N NaOH and dilute with CO2-free water to100mL.Dissolve100mg of Alizarin Red S in100mL CO2-free H2O.Mix equal portions of Bromocresol Green and Alizarin Red S solutions to form mixed

indicator.--` ` ` , ` ` , , ` , ` ` , ` , , , , ` ` ` ` ` , , , ` , ` -` -` , , ` , , ` , ` , , ` ---

国家开放大学C语言程序设计A第一次形考任务及答案

一、选择题（共40分，每小题2分）题目1 在每个C语言程序中都必须包含有这样一个函数，该函数的函数名为（）。 A. main B. MAIN C. name D. function 题目2 C语言源程序文件的缺省扩展名为（）。 A. cpp B. exe C. obj D. c 题目3 由C语言目标文件连接而成的可执行文件的缺省扩展名为（）。 A. cpp B. exe C. obj D. c 题目4 程序运行中需要从键盘上输入多于一个数据时，各数据之间应使用的分隔符为（）。 A. 空格或逗号 B. 逗号或回车 C. 逗号或分号

D. 空格或回车题目5 每个C语言程序文件的编译错误被分为（）。 A. 1类 B. 2类 C. 3类 D. 4类题目6 不符合C语言规定的复合语句是（）。 A. {} B. {;} C. {x=0;} D. {y=10} 题目7 C语言程序中的基本功能模块为（）。 A. 表达式 B. 标识符 C. 语句 D. 函数题目8 在一个函数定义中，函数头包括的3个部分依次为函数类型、函数名和（）。 A. 表达式 B. 语句 C. 参数表

D. 函数体题目9 在一个程序文件中，若要使用#include命令包含一个用户定义的头文件，则此头文件所使用的起止定界符为一对（）。 A. 尖括号 B. 双引号 C. 单引号 D. 花括号题目10 在C语言程序中，多行注释语句使用的开始标记符为（）。 A. // B. /* C. */ D. ** 题目11 在printf()函数调用的格式字符串中，若使用格式符为“%c”，则对应输出的数据类型为（）。 A. char B. int C. float D. double 题目12 在printf()函数调用的格式字符串中，若使用格式符为“%5d”，则规定对应输出的数据占用的字符位置个数为（）。

第10章C语言程序设计习题答案

C 语言程序设计( Visual C++6.0 环境)》习题答案习题十、思考题 1．简述公有类型成员与私有类型成员的区别。公有(public) 类型成员不但可以被类的成员函数访问，而且可以被外界访问，所以说公有类型定义了类的外部接口。私有(private) 类型成员只能被类的成员函数访问，外界不能直接访问它。类的数据成员一般都应该声明为私有成员。 2．简述构造函数与析构函数的作用。构造函数的作用就是在对象在被创建时利用特定的值构造对象，将对象初始化。析构函数的作用与构造函数正好相反，它是用来在对象被删除前进行一些清理工作。析构函数调用之后，对象被撤消了，相应的内存空间也将被释放。 3．简述什么是友元函数。友元函数是在类定义中由关键字friend 修饰的非成员函数。友元函数可以是一个普通函数，也可以其它类中的一个成员函数，它不是本类的成员函数，但它可以访问本类的私有成员和保护成员。 4．简述公有继承、私有继承和保护继承三种继承方式的区别。 ⑴、当类的继承方式为公有(public 继承)时，基类的公有(public )成员和保护( protected )成员仍然成为派生类的公有成员和保护成员，而基类的私有成员不能被派生类访问。 ⑵、当类的继承方式为保护( protected )继承时，基类的公有(public )成员和保护( protected )成员将成为派生类的保护成员，而基类的私有成员不能被派生类访问。 ⑶、当类的继承方式为私有(private )继承时，基类的公有(public )成员和保护(protected )成员将成为派生类的私有成员，而基类的私有成员不能被派生类访问。5．定义一个圆柱体类，其属性为圆柱体的底面半径和高，能计算出圆柱体的体积。 #include class cylinder { public: cylinder(float r,float h) { radius=r; height=h; } float Volume(); private: float radius; float height;

C语言程序设计第11.12章测试答案

第一题、单项选择题（每题1分，5道题共5分） 1、设有定义“int a＝3,b,*p＝&a;”，则下列语句中，使b不为3的语句是： A、b＝*&a; B、b=*p; C、b=a; D、b=*a; 2、在C语言中，关于文件存取方式，： A、只能顺序存取 B、只能随机存取（也称直接存取） C、可以顺序存取，也可以随机存取 D、只能从文件开头存取 3、fp 是文件指针，str 是一个字符串，n是一个整数，向文件中输出数据的正确格式是： A、fprintf("％s,％d\n",str,n,fp); B、fprintf(fp,"％s,％d\n",str,n); C、fprintf("fp ％s,％d\n",str,n); D、fprintf("％s,％d fp\n",str,n); 4、若有int a＝3,*pa; float f＝4.5,*pf＝&f;，则下列表述中，错误的是 ( )。 A、pa=&a B、pa=&f C、pf=&f D、*pf＝a+f 5、若有int a[10],*p＝a;，则( )。 A、p++可以使p指向下一个字节 B、p+＝2 相当于p＝sizeof(a)/10 C、p++可以使p指向下一个元素，即a[1]的首地址 D、p+＝2可以使p指向下一个元素，即a[1]的首地址第二题、多项选择题（每题2分，5道题共10分） 1、C语言中的文件分类是： A、文本文件和数据文件 B、文本文件和二进制文件 C、数据文件和二进制文件 D、顺序文件和随机文件 2、以读写方式打开一个二进制文件fil2，fopen函数的正确的调用方式是： A、FILE *FP; FP＝fopen("fil2","r"); B、FILE *FP; FP＝fopen("fil2","rb");

C语言程序设计入门经典例题

1、加法练习程序：由用户通过键盘输入加数和被加数，程序显示加法式子，用户通过键盘作答后，程序给出正确与错误提示信息。要求：利用C的选择语句if条件语句或switch 开关语句，键盘输入数据前，程序会出被输入数据的信息提示。 #include void main(){ int a,b,c; printf("please put an addend:\n");scanf("%d",&a); printf("please put an augend:\n");scanf("%d",&b); printf("please answer the question:a+b=?")；scanf("%d",&c); if(a+b==c) printf("very good!"); else printf("wrong! "); } 个人感觉这个程序最不好的地方是，不管回答正确还是回答错误，程都会立即结束，所以我用了do…while实现一个回答错误之后获得再次回答机会的循环，则程序修改如下： #include void main(){ int a,b,c; printf("请输入一个加数:\n");scanf("%d"，&a); printf("请输入一个被加数:\n");scanf("%d",&b); do { printf("请回答:a+b=")；scanf("%d",&c); if(a+b!=c) printf("请再想一想\n"); } while(a+b==c) printf("回答正确!"); } 2、判闰年程序：判断某一年是否闰年? 要求：程序首先提示用户从键盘输入4位数年份，程序能显示“XXXX年是闰年”或“XXXX年不闰年”的输出信息。算法：year 是闰年,即year能被4整除但不能被100整除,或 year 能被 400 整除。其对应的C逻辑表达式为：(year % 4 = = 0 && year % 100 != 0) || (year % 400 = = 0) 或: (!(year % 4) && year % 100) || !(year % 400 ) 程序中可设置1个变量leap来代表是否闰年的信息,闰年：leap=1; 不闰年：leap=0。 #include void main() int year; printf("请输入4位数年份:");scanf("%d",&year); if(year%4==0&&year%100!=0||year%400==0)//闰年就是能被4整除但不能被100整除及能被400整除的

《C语言程序设计》第10章在线测试

A B C D 、下列描述中，合法的数组定义是： A B C D 程序的执行是从 A B C D 、下列语句中，正确的语句定义是 A B C D int a[3][4]; A B C D

2、若形参是简单变量形式，则对应的实参可以是： A、常量 B、数组名 C、简单变量 D、数组元素 3、下列描述中，合法的数组定义是( )。 A、char a[]＝{“String”}; B、char a[5]＝{0,1,2,3,4};这组题特BT，答案明明是D，却ABCD全要选才算正确，让我测了N回！ C、char a[]＝“String”; D、char a[]＝{0,1,2,3,4,5}; 4、下列描述中，不能正确给字符数组str定义和赋值的是( )。 A、char str[]＝{"abcdefghijklmn "}; B、char str[10];str＝{" abcdefghijklmn "}; C、char str[10]＝{"abcdefghijklmn"}; D、char str[10];strcpy(str,"abcdefghijklmn"); 5、如果想使下列数组a中5个元素的值全部为0，可以写成( )。 A、int a[5]＝{0:5}; B、int a[5]＝{0}; C、int a[5]＝{5:0}; D、int a[5]＝{0,0,0,0,0}; E、int a[5]＝0; 第三题、判断题（每题1分，5道题共5分） 1、若有func((v1,v2),(v3,v4,v5),v6)调用，说明函数func有6个形参。正确错误 2、在说明一个结构体变量时系统分配给它的存储空间是该结构体中所有成员所需存储空间的总和。

国家开放大学C语言程序设计A第一次形考任务与答案(20201127230652)

一、选择题（共40分，每小题2分） 1 题目1 在每个C语言程序中都必须包含有这样一个函数，该函数的函数名为（）* A.main B. MAIN C. name D. function 题目2 1 C语言源程序文件的缺省扩展名为（）。 A. cpp B. exe C. obj * D.c 题目3 1 由C语言目标文件连接而成的可执行文件的缺省扩展名为（）。 A. cpp B. exe C. obj D. c 题目4

程序运行中需要从键盘上输入多于一个数据时，各数据之间应使用的分隔符为（） A. 空格或逗号 B. 逗号或回车 C. 逗号或分号

* D.空格或回车题目5 1 每个C语言程序文件的编译错误被分为（）。 A. 1类 ” B.2 类 C. 3类 D. 4类题目6 不符合C语言规定的复合语句是（）。 A. {} B. {；} C. {x=0;} + D.{y=10} 题目7 1 C语言程序中的基本功能模块为（）。 A. 表达式 B. 标识符 C. 语句 D. 函数题目8 在一个函数定义中，函数头包括的3个部分依次为函数类型、函数名和（）

B. 语句 C. 参数表 D. 函数体题目9 1 在一个程序文件中，若要使用#include命令包含一个用户定义的头文件，则此头文件所使用的起止定界符为一对（）。 A. 尖括号 * B.双引号 C. 单引号 D. 花括号题目10 L 在C语言程序中，多行注释语句使用的开始标记符为（）。 A. // + B./* C.*/ D ** 题目11 1 在printf（）函数调用的格式字符串中，若使用格式符为“％C'，则对应输出的数据类型为（）。

第10章C语言程序设计习题答案

《C语言程序设计（Visual C++6.0环境）》习题答案习题十一、思考题 1．简述公有类型成员与私有类型成员的区别。公有(public)类型成员不但可以被类的成员函数访问，而且可以被外界访问，所以说公有类型定义了类的外部接口。私有(private)类型成员只能被类的成员函数访问，外界不能直接访问它。类的数据成员一般都应该声明为私有成员。 2．简述构造函数与析构函数的作用。构造函数的作用就是在对象在被创建时利用特定的值构造对象，将对象初始化。析构函数的作用与构造函数正好相反，它是用来在对象被删除前进行一些清理工作。析构函数调用之后，对象被撤消了，相应的内存空间也将被释放。 3．简述什么是友元函数。友元函数是在类定义中由关键字friend修饰的非成员函数。友元函数可以是一个普通函数，也可以其它类中的一个成员函数，它不是本类的成员函数，但它可以访问本类的私有成员和保护成员。 4．简述公有继承、私有继承和保护继承三种继承方式的区别。 ⑴、当类的继承方式为公有（public继承）时，基类的公有（public）成员和保护（protected）成员仍然成为派生类的公有成员和保护成员，而基类的私有成员不能被派生类访问。 ⑵、当类的继承方式为保护（protected）继承时，基类的公有（public）成员和保护（protected）成员将成为派生类的保护成员，而基类的私有成员不能被派生类访问。 ⑶、当类的继承方式为私有（private）继承时，基类的公有（public）成员和保护（protected）成员将成为派生类的私有成员，而基类的私有成员不能被派生类访问。 5．定义一个圆柱体类，其属性为圆柱体的底面半径和高，能计算出圆柱体的体积。 #include class cylinder { public: cylinder(float r,float h) { radius=r; height=h; } float Volume(); private: float radius; float height;

C语言程序设计实习报告

手机通讯录管理系统一、设计题目的任务和内容任务：本程序是非数值计算型算法设计，我设计出了通讯录管理系统的基本功能，并设计了简单的界面。本程序主要考察对自定义函数的熟悉程度，本程序主要使用的是数组的相关操作，包括结构体数组的输入、输出、查找、删除等。我设计的这个通讯录系统也初步实现了人员信息的显示、删除、查找、修改、添加等必要的功能。具体要求： ◆建立通讯录信息，信息包含、姓名、分类（1、办公类2、个人类3、商务类）、电话、电子邮箱等； ◆将通讯录保存在文件中； ◆查看功能：可按1、办公类2、个人类3、商务类分类查询，当选中其中一类时，显示出此类所有数据中的姓名和电话号码。 ◆增加功能：能录入新数据。当录入重复姓名和电话号码时，则提示数据录入重复并取消录入；当通讯录中超过15条信息时，存储空间已满，不能录入新数据；录入的新数据能按递增的顺序自动进行条目编号。 ◆修改功能：选中某个人的姓名是，可对此人的相应数据进行修改。 ◆删除功能：选中某个人的姓名是，可对此人的相应数据进行删除并自动调整后续条目编号。系统功能需求分析：查询：查询通讯录记录添加：添加通讯录记录显示：显示通讯录记录删除：删除通讯录记录修改：修改通讯录记录

二、总体设计思路本系统首先设计出了主函数，然后根据去要实现的功能分别设计拉，显示、删除、查找、修改、添加功能的子函数。在显示的函数设计过程中首先运用拉文件的读取等必要的知识通过把文件的内容读取到内存然后打印出来。删除函数的设计是首先从文件内找到要删除的人，然后通过写一个实现删除目的的FOR循环将该人从内存里删除，然后再用写的方式打开文件，将内存内的信息写入文件，实现删除。查找也是先打开文件，用一个字符串对比的方法找出用户要查找的人，然后打印出来。修改也大体和删除相同，添加函数在设计时通过申请一片空间，然后通过指针将需要添加的信息添加进去，从而实现添加功能。系统功能模块图：输入新信息：可输入新的数据。添加：可以添加通讯录记录，依次输入姓名、电话号码、分类、电子邮箱后，会提示是否继续添加。删除：输入姓名删除，输入欲删除的那个人的名字后，会自动删除他（她）的记录内容查询：可按1、办公类2、个人类3、商务类分类查询修改：输入欲修改的那个人的名字后，再依次输入姓名、电话号码、分类、电子邮箱即可完成修改。下面就是总的程序流程图：

C语言程序设计第一次月考试题

C语言程序设计第一次月考试题（2011.9）班级：姓名：总分：一、选择题（每小题3分，共60分） 1．一个C语言程序是由（） A）一个主程序和若干子程序组成B）函数 C）若干过程组成D）若干子程序组成 2．下面4个选项中，均是C语言关键字的选项是（） A）auto enum include B)switch typedef continue C)singed union scanf D)if struct type 3. 下面4个选项中，均是不合法的用户标识符的选项是（） A）A P_0 do B)float 1a0 -A C) b—a goto int D) _123 temp INT 4.下面4个选项中，均是不合法的整形常量的选项是（） A）- - 0f1 - oxfff 0011 B)- oxcdf 017 12,456 C) – 018 999 5e2 D)-0x48eg -068 03f 5. 下面4个选项中，均是不合法的浮点数的选项是（） A）160．0.12 e3 B)123 2e4.2 .e5 C）-.18 123e4 0.0 D)-e3 .234 1e3 6.下面4个选项中，均是不合法的转义字符的选项是（） A）‘\‖‘?\\‘?\xf‘B)‘\1011‘?\‘?\a‘ C) ?\011‘?\f‘?\}‘D)‘\abc‘?\101‘?x1f‘ 7.下面不正确的字符串常量是（） A）‘abc‘B)‖12‘12‖C) ‖0‖D)‖‖ 8．Int k=7, x=12; 则以下能使值为3的表达式是（） A）x%=(k%=5) B)x%=(k- k%5) C) x%=k-k%5 D)(x%=k) – (k%=5) 9.若x、i、j和k都是int型变量，则执行表达式x=(i=4,j=16,k=32)后x的值是（） A) 4 B)16 C)32 D)52 10．假设所有变量均为整型，则表达式(a=2,b=5,b++,a+b)的值是( ) A) 7 B) 8 C)6 D)2 11.已知各变量的类型说明如下： Int k, a, b; unsigned long w=5; double x=1.42; 则以下不正确的表达式是（） A) x%(-3) B)w+=-2 C) k=(a=2,b=3, a+b) D)a+=a-=(b=4)*(a=3) 12.已知字母A的ASCII码为65，且定义c2为字符型变量，则执行语句c2=‘A‘+‘6‘-?3‘;后；c2中的值为（） A) D B) 68 C)不确定的值D) C

《C语言程序设计》第10章

《C语言程序设计》第10章在线测试 A B D C 函数体 A B C D int a[][3] A B C D int a[3][4]; A B C D int a[][3]的第1维的长度为 A B C D

D、printf("％s",c[3].name[2]); 2、下列描述中，合法的数组定义是： A、char a[5]＝{’A’,’B’,’C’,’D’,’E’}; B、char a[]＝{’A’,’B’,’C’,’D’,’E’}; C、char a[]＝"ABCDE"; D、char a[]＝{65,66,67,68,69,70}; 3、若形参是简单变量形式，则对应的实参可以是： A、常量 B、数组名 C、简单变量 D、数组元素 4、下列关于对二维数组a进行初始化的操作中，正确的写法是( )。 A、int a[][3]＝{3,2,1,1,2,3}; B、int a[][]＝{{3,2,1},{1,2,3}}; C、int a[][3]＝{{3,2,1},{1,2,3}}; D、int a[2][3]＝{{3,2,1},{1,2,3}}; 5、在定义int a[2][3];之后，对数组a的引用错误的是( )。 A、a(1,2) B、a[1,3] C、a[2][0] D、a[1＞2][!1] 第三题、判断题（每题1分，5道题共5分） 1、在说明一个结构体变量时系统分配给它的存储空间是该结构体中所有成员所需存储空间的总和。正确错误 2、数组必须先定义后使用。

正确错误、可以在定义数组时对数组元素赋予初值。正确错误、可以在定义数组时只给一部分数组元素赋值。正确错误、对数组元素赋予的初值可以依次放在一对圆括号内。正确错误

c语言第1章练习题答案

第一章 C语言概述练习题一、选择题 1.C语言是一种( )。 A) 机器语言B) 汇编语言C) 高级语言 D) 低级语言 2.下列各项中，不是C语言的特点是( )。 A) 语言简洁、紧凑，使用方便B) 数据类型丰富，可移植性好 C) 能实现汇编语言的大部分功能D) 有较强的网络操作功能 3.下列叙述正确的是( )。 A) C语言源程序可以直接在DOS环境中运行 B) 编译C语言源程序得到的目标程序可以直接在DOS环境中运行 C) C语言源程序经过编译、连接得到的可执行程序可以直接在DOS环境中运行 D) Turbo C系统不提供编译和连接C程序的功能 4.下列叙述错误的是（）。 A) C程序中的每条语句都用一个分号作为结束符 B) C程序中的每条命令都用一个分号作为结束符 C) C程序中的变量必须先定义，后使用 D) C语言以小写字母作为基本书写形式，并且C语言要区分字母的大小写 5.一个C程序的执行是从（）。 A) 本程序的main函数开始，到main函数结束 B) 本程序文件的第一个函数开始，到本程序文件的最后一个函数结束 C) 本程序文件的第一个函数开始，到本程序main函数结束 D) 本程序的main函数开始，到本程序文件的最后一个函数结束 6.以下叙述不正确的是（）。 A) 一个C源程序必须包含一个main函数 B) 一个C源程序可由一个或多个函数组成 C) C程序的基本组成单位是函数 D) 在C程序中，注释说明只能位于一条语句的后面 7.C语言规定:在一个源程序中,main函数的位置( )。 A)必须在程序的开头B)必须在系统调用的库函数的后面 C)可以在程序的任意位置D)必须在程序的最后 8.一个C语言程序是由( )。 A)一个主程序和若干个子程序组成B) 函数组成 C) 若干过程组成D) 若干子程序组成 9.以下有4组用户标识符，其中合法的一组是（）。 A) For B) 4d C) f2_G3 D) WORD -sub DO IF void Case Size abc define 10. 一个算法应该具有“确定性”等5个特性，下面对另外4个特性的描述中错误的是（）。

C语言程序设计习题及答案

C语言程序设计一、选择题（共40分，每小题2分） 1、以下叙述不正确的是（） A、一个C源程序可由一个或多个函数组成 B、一个C源程序必须包含一个main函数 C、C程序的基本组成单位是函数 D、在C程序中，注释说明只能位于一条语句的后面 2、下列四个选项中，是不合法的用户标识符的选项是（） A、abc B、12AC C、sun D、 A2 3、设有语句int a=4；则执行了语句a+=a- =a*a后，变量a的值是（） A、-24 B、0 C、4 D、16 4、下列运算符中优先级最高的是（） A、< B、+ C、&& D、== 5、在C语言中，运算对象必须是整型数的运算符是（） A、％ B、／ C、％和／ D、 + 6、以下关于运算符的优先顺序的描述正确的是（） A、关系运算符<算术运算符<赋值运算符<逻辑与运算符 B、逻辑与运算符<关系运算符<算术运算符<赋值运算符 C、赋值运算符<逻辑与运算符<关系运算符<算术运算符 D、算术运算符<关系运算符<赋值运算符<逻辑与运算符 7、在C语言中，如果下面的变量都是int类型，则输出的结果是（）sum=pad=5；pAd=sum++，pAd++，++pAd； printf(“％d\n”，pad)；

A、7 B、6 C、5 D、4 8、x、y、z被定义为int型变量，若从键盘给x、y、z输入数据，正确的输入语句是（） A、 INPUT x、y、z； B、scanf(“%d%d%d”，&x，&y，&z)； C、 scanf(“%d%d%d”，x，y，z)； D、read(“%d%d%d”，&x，&y，&z)； 9、假定从键盘输入23456< 回车 >，下面程序的输出结果是：（） void main ( ) { int m，n； scanf(“%2d%3d”，&m，&n)； printf(“m=%d n=%d\n”，m，n)； } A、m=23 n=45 B、m=234 n=56 C、m=23 n=456 D、语句有错误 10、若运行时，给变量x输入12，则以下程序的运行结果是（） main( ) { int x，y； scanf(“%d”，&x)； y=x>12x+10：x-12； printf(“%d\n”，y)； } A、 0 B、 22 C、 12 D、10 11、C语言中while和do-while循环的主要区别（） A、do-while的循环体至少执行一次 B、while 的循环控制条件比do-while的循环控制条件严格 C、do-while允许从外部转到循环体内

C语言语言程序设计第8.9.10章测试答案

A B C D int a[2][3]; A B C D 程序的执行是从 A B C D 、下列说法中，错误的说法是 A B D C 函数体 A B C D

B、函数必须有返回值，否则不能使用函数 C、C程序中有调用关系的所有函数必须放在同一个源程序文件中 D、在C中，调用函数时，只能把实参的值传送给形参，形参的值不能传送给实参 3、根据定义： struct person{char name[9];int age;}; struct person c[10]＝{"John",17,"Paul",19,"Mary",18,"Adam",16}; 能打印出字母M的语句是：C D A、printf("％s",c[0].name); B、printf("％s",c[1].name[0]); C、printf("％s",c[2].name[1]); D、printf("％s",c[3].name[2]); 4、若形参是简单变量形式，则对应的实参可以是： A、常量 B、数组名 C、简单变量 D、数组元素 5、下列关于对二维数组a进行初始化的操作中，正确的写法是( )。 A、int a[][3]＝{3,2,1,1,2,3}; B、int a[][]＝{{3,2,1},{1,2,3}}; C、int a[][3]＝{{3,2,1},{1,2,3}}; D、int a[2][3]＝{{3,2,1},{1,2,3}}; 第三题、判断题（每题1分，5道题共5分） 1、数组名的命名规则和变量名的命名规则相同正确错误 2、若有func((v1,v2),(v3,v4,v5),v6)调用，说明函数func有6个形参。正确错误 3、数组必须先定义后使用。

2020年智慧树知道网课《C语言程序设计(西华大学)》课后章节测试满分答案

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3 【单选题】(5分) C语言的注释定界符是（）。 A. [] B. /**/ C. \**\ D. {} 4 【单选题】(5分) C语言源程序的基本单位是（）。 A. 过程 B. 标识符 C. 子程序 D. 函数

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7 【单选题】(5分) 有一个命名为C001.C的C语言源程序，当正常执行后，在当前目录下不存在的文件是 A. C001.EXE B. C001.C C. C001.OBJ D. C001.DAT 8 【单选题】(5分) 能将高级语言编写的源程序转换为目标程序的是（）。 A. 编辑程序 B. 链接程序 C. 解释程序 D. 编译程序

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C语言程序设计心得体会在这为期半个月的时间内，通过我们小组各成员之间的相互讨论和合作，我们完成了学生信息管理系统的程序设计，更值得高兴的是我们的程序得到了大家的喜爱，在每次的简报中都得到了较好的成绩。虽然在上个学期中，我们已经学习了《C 语言程序设计》这门课，但是我所学的知识最多也就是在做作业的时候才会用到，平时没有什么练习的机会，这次的课程设计是我第一次通过自己构思，和同学讨论并且不断查阅资料来设计一项程序。这次设计，不仅巩固了我以前所学的知识，还让我对c语言有了更深一步的了解，掌握了更多的技巧和技能。 C语言是计算机程序设计的重要理论基础，在我们以后的学习和工作中都有着十分重要的地位。要学好这种语言，仅仅学习课本上的知识是不够的，还要经常自己动手，有较强的实践能力。只有多动手，经常编写程序，才能发现我们学习上的漏洞和自己的不足，并在实践中解决这些问题，不断提高自己转化知识的能力。在我们小组有解决不了的问题时，我们会主动查阅相关的资料，或向其他同学询问，这不仅丰富了我们的知识，还增进了我们同学之间的友谊。为了增大信息的安全性，需要用文件来存储信息，由于我们在上课时不注重对文件的运用，所以在这方面有较大的困难。我先将书本认认真真地看了一遍，又做了一下课后习题来验证和增进自己的理解，终于，经过我们的不懈努力，我们小组的程序有了突破，成功地实现了用文件来保存并查看学生的信息。这次设计中，我的收获还有就是学会了用流程图来表达自己的想法，并根据流程图来逐步实现程序的功能。开始的时候，我画流程图很是困难，需要一个多小时才能清楚的根据自己的想法画出图来，后来画多了，就更加了解它的功能，十分得心应手，能够比较快而准确的画出来。在这次课程设计中，我们首先对系统的整体功能进行了构思，然后用结构化分析方法进行分析，将整个系统清楚的划分为几个模块，再根据每个模块的功能编写代码。而且尽可能的将模块细分，最后在进行函数的调用。我们在函数的编写过程中，我们不仅用到了for循环、while循环和switch语句，还用到了函数之间的调用（包括递归调用）。由于我们是分工编写代码，最后需要将每个人的代码放到一起进行调试。因为我们每个人写的函数的思想不都一样，所以在调试的过程中也遇到了困难，但经过我们耐心的修改，终于功夫不负有心人，我们成功了！在参考书上，我们不仅参考了曾经学过的高敬阳主编的《c语言程序设计》，还找到了由谭浩强主编的第三版《c语言》进行参考。

《C语言程序设计教程》(第三版)李凤霞主编——第十章习题答案

习题十一、单选题 1~5 DDDCC 6~10 AABDB 11~14 CADC 二、填空题 1、34 12 2、ARRAY a,b,c; 3、1 3 4、a c 5、(*b).day=？ b->day＝？ 5、分析下列程序执行结果。 #include “stdio.h” main() {static struct s1 {char c[4],*s; s1={“abc”,”def”}; static struct s2 {char *cp;struct s1 ss1; }s2={“ghi”,{“jkl”,”mno”}}; printf(“%c%c\n”,s1.c[0],*s1.s); /*output ab */ printf(“%s%s\n”,s1.c,s1.s); /*output abcdef */ printf(“%s%s\n”,s2.cp,s2.ss1.s); /*output ghimno */ printf(“%s%s\n”,++s2.cp,++s2.ss1.s); /* output hino */ } 6、以下程序的功能是：读入一行字符（如：a,...,y,z）,按输入时的逆序建立一个链式的结点序列，即先输入的位于链表尾（如下图），然后再按输入的相反顺序输出，并释放全部结点。 #define getnode(type)_________malloc(sizeof(type)) ( (struct node *)) main() {struct node {char info; struct node *link; }*top,*p; char c; top=NULL; while((c=getchar())______________) （!='\n'） {p=getnode(struct node); p->info=c; p->link=top; top=p; } while(top) {_________________; (p=top) top=top->link; putchar(p->info); free(p);

c语言程序设计何钦铭颜晖第10章函数与程序结构

第10章函数与程序结构【练习10-1】使用递归函数计算1到n之和：若要用递归函数计算sum=1+2+3+…+n（n为正整数），请写出该递归函数的递归式子及递归出口。试编写相应程序。解答：递归式子: sum(i) = sum(i-1) + i; 递归出口: sum(i) = 0; 【练习10-2】请完成下列宏定义： ① MIN(a,b) 求 a,b 的最小值 ② ISLOWER(c) 判断 c 是否为小写字母 ③ ISLEAP(y) 判断 y 是否为闰年 ④ CIRFER(r) 计算半径为 r 的圆周长解答： ① MIN(a, b)：求a,b的最小值。 #define MIN(a,b) (a='a'&&c<='z') ③ ISLEAP(y)：判断y是否为闰年。 #define ISLEAP(y) (y%4==0&&y%100!=0)||y%400==0) ④ CIRFER(r)：计算半径为r的圆周长。 #define PI #define CIRFER(r) 2*PI*(r) 【练习10-3】分别用函数和带参宏实现从 3 个数中找出最大数，请比较两者在形式上和使用上的区别。解答：（1）函数实现 int max(int x,int y,int z) { int t; if(x>=y) if(x>=z) t=x; else t=z; else if(y>=z) t=y; else t=z; return t; } （2）宏实现 #define MAX( x, y, z ) x>=y (x>=z x:z) : (y>=z y:z)两者在定义形式上

C语言程序设计_第一阶段练习参考答案

江南大学现代远程教育第一阶段练习题考试科目:《C语言程序设计》第一章至第四章（总分100分）学习中心（教学点）批次：层次：专业：学号：身份证号：姓名：得分：一单选题 (共20题，总分值40 ，下列选项中有且仅有一个选项符合题目要求，请在答题卡上正确填涂。) 1. 有以下程序 main() { int i=1,j=1,k=2; if((j++‖k++)&&i++) printf("%d,%d,%d\n",i,j,k); } 执行后输出结果是（）。（2 分） A. 1，1，2 B. 2，2，1 C. 2，2，2 D. 2，2，3 2. 已有定义:int x=3,y=4,z=5；，则表达式!(x+y)+z-1 && y+z/2的值是（）。（2 分） A. 6 B. 0 C. 2 D. 1 3. 执行以下程序段后，变量a,b,c的值为（）。 int x=11,y=10,a,b,c; a=(--x==y++)?--x:++y; b=x++; c=y; （2 分） A. a=10,b=10,c=9 B. a=9,b=9,c=12 C. a=9,b=9,c=11 D. a=1,b=9,c=11 4. 以下程序的输出结果是用（）表示。 main( ) { int k=17；

printf("%d，%o，%x \n"，k，k，k)； } （2 分） A. 17，021，0x11 B. 17，17，17 C. 17，0x11，021 D. 17，21，11 5. 已知i、j、k为int型变量，若从键盘输入：1，2，3<回车> ，使i的值为1、j的值为2、 k的值为3，以下选项中正确的输入语句是（）。（2 分） A. scanf(“%2d%2d%2d”,&i,&j,&k); B. scanf(“%d %d %d”,&i,&j,&k); C. scanf(“%d,%d,%d”,&i,&j,&k); D. scanf(“i=%d,j=%d,k=%d”,&i,&j,&k); 6. 以下非法的赋值语句是（）。（2 分） A. n=(i=2,++i); B. j++; C. ++(i+1); D. x=j＞0; 7. 已知c是字符型变量，以下不正确的赋值语句是（）。（2 分） A. c=”a” B. c=’a’ C. c=’\141’ D. c=’\x61’+3 8. 以下不符合C语言语法的赋值表达式是（）。（2 分） A. d=9+e,e++,d+9 B. k=i= =j C. n1+=n2+3 D. a=b+c=a+7 9. 若有以下程序： main() { int k=2,i=2,m; m=(k+=i*=k); printf(“%d,%d\n”,m,i);} 执行后的输出结果是（）。（2 分） A. 8，6 B. 8，3 C. 6，4 D. 7，4 10. 字符串”\\\’abcd\123\xAB\t”的长度为（）。（2 分） A. 8 B. 17 C. -9 D. 10 11. 若有如下程序段，其中s、a、b、c均已定义为整型变量，且a、c均已赋值(c大于0) s=a; for(b=1;b＜=c;b++) s=s+1; 则与上述程序段功能等价的赋值语句是（）。（2 分）

《C语言程序设计》课程教学大纲

《C语言程序设计》课程教学大纲一、课程教学目的本课程系统学习 C语言的基本知识和基本语法，较好地训练学生解决问题的逻辑思维能力以及编程思路和技巧，使学生具有较强的利用 C 语言编写软件的能力，为培养学生有较强软件开发能力打下良好基础。二、课程教学要求通过本课程的学习，应熟练掌握 C 语言中的基本知识、各种语句及程序控制结构，熟练掌握 C 语言的函数、数组、指针、结构体、链表等数据结构的基本算法；并能熟练地运用 C 语言进行结构化程序设计；具有较强的程序修改调试能力；具备较强的逻辑思维能力和独立思考能力。三、课时分配本学科计划学时为246学时，其中理论与实训课时比例为7:3。四、课程教学重、难点课程教学重点：掌握C语言变量类型及不同类型常量的表示；标准的输入输出函数的使用；运算符及常用数学函数的使用；控制流程、数组和指针的使用；结构体、链表的构造使用；函数结构、函数参数传递及递归等方面的知识；基本的文件操作。难点：指针的使用、结构体链表的构造和使用及函数的参数传递。五、课程教学方法（或手段）本课程实践性较强，故采用讲授和上机操作相结合的方式进行教学。六、课程教学内容第一章 C语言概述 1．教学内容 (1) 编程历史的回顾、程序设计介绍（过程式，面向对象，函数式，逻辑式）； (2) C语言的历史背景、特点； (3) C语言源程序的格式和程序结构； (4) C程序的上机步骤。 2．重、难点提示（1）重点：掌握简单的 C程序格式，包括main()函数、数据说明、函数开始和结束标志等；

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