1、Designation: C25 17Standard Test Methods forChemical Analysis of Limestone, Quicklime, and HydratedLime1This standard is issued under the fixed designation C25; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revis
2、ion.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 These test methods cover the chemical analysis
3、 ofhigh-calcium and dolomitic limestone, quicklime, and hy-drated lime. These test methods are classified as either standard(preferred) or alternative (optional).1.2 The standard test methods are those that employ classi-cal gravimetric or volumetric analytical procedures and aretypically those requ
4、ired for referee analyses where chemicalspecification requirements are an essential part of contractualagreement between buyer and seller.1.3 Alternative or optional test methods are provided forthose who wish to use procedures shorter or more convenientthan the standard methods for the routine dete
5、rminations ofcertain constituents. Optional test methods may sometimes bepreferred to the standard test methods, but frequently the use ofmodern and expensive instrumentation is indicated which maynot be accessible to everyone. Therefore, the use of these testmethods must be left to the discretion o
6、f each laboratory.1.4 The analytical procedures appear in the following order:SectionAluminum Oxide 15Available Lime Index 28Calcium and Magnesium Oxide:Alternative EDTA Titration Method 31Calcium Carbonate Equivalent 33Calcium Oxide:Gravimetric Method 16Volumetric Method 17Carbon Dioxide by Standar
7、d Method 22Combined Oxides of Iron and Aluminum 12Ferrous Iron Appendix X5Free Calcium Oxide Appendix X6Free Moisture in Hydrated Lime 21Free Moisture in Limestone 20Free Silica 29Insoluble Matter Including Silicon Dioxide:Standard Method 8Optional Perchloric Acid Method 9Insoluble Matter Other Than
8、 Silicon Dioxide 11Loss on Ignition 19Magnesium Oxide 18Manganese:Bismuthate Method Appendix X4Periodate (Photometric) Method 27pH Determination of Alkaline Earth Solutions 34Phosphorus:Titrimetric Method Appendix X3Molybdovanadate Method 26Silicon Dioxide 10Strontium Oxide Appendix X2Sulfur Trioxid
9、e 23Total Carbon:Direct Combustion-Thermal Conductivity CellMethod32Total Carbon and Sulfur:Combustion Infrared Detection Method 35Total Iron:Standard Method, Potassium DichromateTitration13Potassium Permanganate Titration Method Appendix X1Ortho-Phenanthroline, Photometric Method 14Total Sulfur:Sod
10、ium Carbonate Fusion 24Combustion-Iodate Titration Method 25Unhydrated Oxides 301.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental p
11、ractices and deter-mine the applicability of regulatory limitations prior to use.For specific precautionary statements, see 9.3, 10.2.1, 18.4.3,31.6.4.2, X2.3.1, and X5.4.1.1.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization e
12、stablished in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:21These test methods are under the jurisdiction of ASTM Comm
13、ittee C07 onLime and Limestone and are the direct responsibility of Subcommittee C07.05 onChemical Tests.Current edition approved Dec. 1, 2017. Published January 2018. Originallyapproved in 1919. Last previous edition approved in 2011 as C25 112. DOI:10.1520/C0025-17.2For referenced ASTM standards,
14、visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428
15、-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technic
16、al Barriers to Trade (TBT) Committee.1C50 Practice for Sampling, Sample Preparation, Packaging,and Marking of Lime and Limestone ProductsC51 Terminology Relating to Lime and Limestone (as usedby the Industry)C911 Specification for Quicklime, Hydrated Lime, andLimestone for Selected Chemical and Indu
17、strial UsesD1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE70 Test Method for pH of Aqu
18、eous Solutions With theGlass ElectrodeE173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals (Withdrawn1998)3E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE200 Practice for Preparation, Standardization, and Storageof Standard and Rea
19、gent Solutions for Chemical AnalysisE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE832 Specification for Laboratory Filter Papers3. Terminology3.1 Definitions:DefinitionsUnless otherwise specified, fordefinitions of terms used in these test methods r
20、efer toTerminology C51.4. Significance and Use4.1 These test methods provide accurate and reliable ana-lytical procedures to determine the chemical constituents oflimestone, quicklime, and hydrated lime (see Note 1). Thepercentages of specific constituents which determine a materi-als quality or fit
21、ness for use are of significance dependingupon the purpose or end use of the material. Results obtainedmay be used in relation to specification requirements.4.2 Because quicklime and hydrated lime quickly absorbwater and carbon dioxide from the air, precision and bias areextremely dependent upon pre
22、cautions taken during samplepreparation and analysis to minimize excessive exposure toambient conditions.NOTE 1These test methods can be applied to other calcareousmaterials if provisions are made to compensate for known interferences.5. General Apparatus and Materials and Reagents5.1 General Appara
23、tus and Materials:5.1.1 BalanceThe balance shall be of an analytical typewith a capacity not to exceed 200 g. It may be of conventionaldesign or it may be a constant-load, direct-reading type. It shallbe capable of reproducing weighings within 0.0002 g with anaccuracy of 60.0002 g. Rapid weighing de
24、vices that may beprovided such as a chain, damper, or heavy riders shall notincrease the basic inaccuracy by more than 0.0001 g at anyreading and with any load within the rated capacity of thebalance.5.1.2 WeightsWeights used for analysis shall conform toClass S-1 requirements of the National Instit
25、ute of Standardsand Technology as described in NIST Circular 547.4They shallbe checked at least once a year or when questioned, andadjusted to within allowable tolerances for Class S-1 weights.All new sets of weights purchased shall have the weights of 1 gand larger made of stainless steel or other
26、corrosion-resistantalloy not requiring protective coating and shall meet thedensity requirements for Class S.5.1.3 Glassware and Laboratory ContainersStandardvolumetric flasks, burets, pipets, dispensers, and so forth, shallbe carefully selected precision grade or better and shall becalibrated, if n
27、ecessary, to meet the requirements of eachoperation. Standard-type interchangeable ground glass or TFE-fluorocarbon joints are recommended for all volumetric glass-ware. Polyethylene containers are recommended for all aque-ous solutions of alkalies and for standard solutions where thepresence of dis
28、solved silica or alkali from the glass would beobjectionable.5.1.4 DesiccatorsDesiccators shall be provided with agood desiccant such as anhydrous magnesium perchlorate,activated alumina, sulfuric acid, or phosphoric anhydride.Anhydrous calcium sulfate may also be used provided it hasbeen treated wi
29、th a color-changing indicator to show when thedesiccant has lost its effectiveness. Calcium chloride and silicagel are not satisfactory desiccants for this type of analysis.5.1.5 Filter PaperFilter paper shall conform to the re-quirements of Specification E832, Type II (quantitative). ClassE shall b
30、e used for coarse and gelatinous precipitates. Whenmedium-textured paper is required, Class F filter paper shall beused. When a retentive paper is needed, Class G shall be used.Recommendations:Class Filter Pore Size (m) Filter SpeedE 20 to 25 fast speedF 8 medium speedG 2.5 slow speed5.1.6 Crucibles
31、Platinum crucibles and tight fitting lidsshould preferably be made of pure unalloyed platinum and beof 25 to 35-mL capacity. Where alloyed platinum is used forgreater stiffness or to obviate sticking of fused material tocrucible or lid, the alloyed platinum should not decrease inweight by more than
32、0.2 mg when heated at 1200C for 1 h.5.1.7 Muffle FurnaceThe electric muffle furnace should becapable of continuous operation up to 1000C and be capableof intermittent operation at higher temperatures if required. Itshould have an indicating pyrometer accurate to 625C.3The last approved version of th
33、is historical standard is referenced onwww.astm.org.4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.C251725.2 Reagents:5.2.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, i
34、t is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society5where such specifications are available. Other grades may beused provided it is first ascertained that the reagent is ofsufficiently high purity to permit its
35、use without lessening theaccuracy of the determination. In addition to this, it is desirablein many cases for the analyst to ensure the accuracy of hisresults by running blanks or checking against a comparablesample of known composition.5.2.2 Purity of WaterUnless otherwise indicated, refer-ences to
36、 water are understood to mean distilled water or otherwater of equivalent purity. Water conforming to SpecificationD1193 meets these requirements.5.2.3 Concentration of Reagents:5.2.3.1 Concentrated Acids and Ammonium HydroxideWhen acids and ammonium hydroxide are specified by nameor chemical formul
37、a only, it shall be understood that concen-trated reagents approximating the following specific gravitiesor concentrations are intended:Acetic acid (HC2H3O2) 99.5 %Hydrochloric acid (HCl) sp gr 1.19Hydrofluoric acid (HF) 48 %Nitric acid (HNO3) sp gr 1.42Perchloric acid (HClO4)70Phosphoric acid (H3PO
38、4)85Sulfuric acid (H2SO4) sp gr 1.84Ammonium hydroxide (NH4OH) sp gr 0.905.2.3.2 Dilute ReagentsThe concentration of dilute acidsand NH4OH except when standardized, are specified as a ratiostating the number of measured volumes of the concentratedreagent to be diluted with a given number of measured
39、 volumesof water. In conformance with international practice, new andrevised methods will use the “plus” designation instead of theratio (:) symbol as the specified designation of dilution; forexample, H2SO4(5 + 95) means 5 volumes of concentratedH2SO4(sp gr 1.84) diluted with 95 volumes of water.5.
40、2.3.3 Standard SolutionsConcentrations of standard so-lutions shall be expressed as normalities (N) or as equivalentsin grams per millilitre of the component to be determined, forexample: 0.1 N K2Cr2O7solution (1 mL = 0.004 g Fe2O3). Theaverage of at least three determinations shall be used for alls
41、tandardizations. The standardization used to determine thestrength of the standard solutions is described in the text undereach of the appropriate procedures.6. General Procedures6.1 SamplingSamples of lime and limestone for chemicalanalysis shall be taken and prepared in accordance with therequirem
42、ents of Practice C50 applicable to the material to betested.6.2 Tared or Weighed CruciblesThe tare weight of cru-cibles shall be determined by preheating the empty crucible toconstant weight at the same temperature and under the sameconditions as shall be used for the final ignition of a residue and
43、cooling in a desiccator for the same period of time used for thecrucible containing the residue.6.3 Constancy of Weight of Ignited ResidueTo definitelyestablish the constancy of weight of the ignited residue, theresidue and container shall be ignited at the specified tempera-ture and time, cooled to
44、 room temperature in a desiccator, andweighed. The residue and container shall then be reheated forat least 30 min at the same temperature, cooled in a desiccatorfor the same period of time, and reweighed.Additional ignitionperiods may be required until two consecutive weights do notdiffer by more t
45、han 0.2 mg, at which time it shall be consideredthat constant weight has been attained. For ignition loss, eachreheating period shall be 5 min.6.4 Calculation:6.4.1 The calculations included in the individual proceduressometimes assume that the exact weight specified has beenused. Accurately weighed
46、 samples which are approximatelybut not exactly equal to the weight specified may be usedprovided appropriate corrections are made in the calculation.Unless otherwise stated, weights of all samples and residuesshould be recorded to the nearest 0.0001 g.6.4.2 In all mathematical operations on a set o
47、f observedvalues, the equivalent of two more places of figures than in thesingle observed values shall be retained. For example, ifobserved values are read or determined to the nearest 0.1 mg,carry numbers to the nearest 0.001 mg in calculation.6.5 Rounding FiguresRounding figures to the nearestsign
48、ificant place required in the report should be done after thecalculations are completed, in order to keep the final resultsfree from calculation errors. The rounding procedure shouldfollow the principle outlined in Practice E29.7. Performance Requirements for Test Methods7.1 Referee AnalysesThe refe
49、rence test methods that ap-pear in Sections 8 through 32, or any other test methodsqualified in accordance with 7.3, are required for refereeanalysis in those cases where conformance to the requirementsof a chemical specification are questioned. In these cases alimestone, quicklime, or hydrated lime shall not be rejected forfailure to conform to chemical requirements unless all samplepreparation and analysis of any one constituent is made entirelyby reference test methods prescribed in the appropriate sectionsof this test method or by other qualified test me
