1、Designation: C25 111Standard 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 revi
2、sion.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.1NOTEDesignation was corrected editorially in December 20
3、14.1. Scope1.1 These test methods cover the chemical analysis 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
4、 volumetric analytical procedures and aretypically those required 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
5、more convenientthan the standard methods for the routine determinations 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,
6、the use of these testmethods must be left to the discretion of each laboratory.1.4 The analytical procedures appear in the following order:SectionAluminum Oxide 15Available Lime Index 28Calcium and Magnesium Oxide:Alternative EDTA TitrationMethod31Calcium Carbonate Equivalent 33Calcium Oxide:Gravime
7、tric Method 16Volumetric Method 17Carbon Dioxide by StandardMethod22Combined Oxides of Iron andAluminum12Ferrous Iron Appendix X5Free Calcium Oxide Appendix X6Free Moisture in Hydrated Lime 21Free Moisture in Limestone 20Free Silica 29Insoluble Matter Including Silicon Dioxide:Standard Method 8Optio
8、nal Perchloric Acid Method 9Insoluble Matter Other Than SiliconDioxide11Loss on Ignition 19Magnesium Oxide 18Manganese:Bismuthate Method Appendix X4Periodate (Photometric) Method 27pH Determination of Alkaline EarthSolutions34Phosphorus:Titrimetric Method Appendix X3Molybdovanadate Method 26Silicon
9、Dioxide 10Strontium Oxide Appendix X2Sulfur Trioxide 23Total Carbon:Direct Combustion-ThermalConductivity Cell Method32Total Carbon and Sulfur:Combustion/Infrared DetectionMethod35Total Iron:Standard Method, PotassiumDichromate Titration13Potassium PermanganateTitration MethodAppendix X1Ortho-Phenan
10、throline,Photometric Method14Total Sulfur:Sodium Carbonate Fusion 24Combustion-Iodate TitrationMethod25Unhydrated Oxides 301These test methods are under the jurisdiction of ASTM Committee C07 onLime and Limestone and are the direct responsibility of Subcommittee C07.05 onChemical Tests.Current editi
11、on approved June 1, 2011. Published July 2011. Originally approvedin 1919. Last previous edition approved in 2006 as C25 06. DOI: 10.1520/C0025-11E01.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.5 This standard does not purport t
12、o 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 and health practices and determine the applica-bility of regulatory limitations prior to use. For specificprecautionary statements, see 9.3, 10.
13、2.1, 18.4.3, 31.6.4.2,X2.3.1, and X5.4.1.1.2. Referenced Documents2.1 ASTM Standards:2C50 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 L
14、ime, andLimestone for Selected Chemical and Industrial 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, a
15、ndRelated MaterialsE70 Test Method for pH of Aqueous 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,
16、 Standardization, and Storageof Standard and Reagent 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, ford
17、efinitions of terms used in these test methods refer 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 constitu
18、ents which determine a materi-als quality or fitness 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, pr
19、ecision and bias areextremely dependent upon precautions 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 Appara
20、tus and Materials and Reagents5.1 General Apparatus 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
21、 with anaccuracy of 6 0.0002 g. Rapid weighing devices 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 confor
22、m toClass S-1 requirements of the National Institute 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 o
23、f 1g and larger made of stainless steel or other 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, etc., shall becarefully selected precision gra
24、de or better and shall becalibrated, if necessary, 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 st
25、andard solutions where thepresence of dissolved 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 al
26、so be used provided it hasbeen treated with 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 E83
27、2, Type II (quantitative). ClassE shall be 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:ClassFilter Pore Size(microns)Filter SpeedE 20 to 25 fast speedF 8
28、 medium speedG 2.5 slow speed5.1.6 CruciblesPlatinum crucibles and tight fitting lidsshould preferably be made of pure unalloyed platinum and beof 25 to 35-mL capacity. Where alloyed platinum is used for2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Ser
29、vice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from National Institute of Standards and Technology (NIST), 100
30、Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.C251112greater stiffness or to obviate sticking of fused material tocrucible or lid, the alloyed platinum should not decrease inweight by more than 0.2 mg when heated at 1200 C for 1 h.5.1.7 Muffle FurnaceThe electric muffle furnace should becapable
31、 of continuous operation up to 1000 C and be capableof intermittent operation at higher temperatures if required. Itshould have an indicating pyrometer accurate to 6 25 C.5.2 Reagents:5.2.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intende
32、d 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 use without
33、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 water are u
34、nderstood 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 formula only, it s
35、hall 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 (H3PO4)85Sulfuric
36、 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 volumesof w
37、ater. 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.5.2.3.3 Standa
38、rd 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 allstandardizati
39、ons. 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 therequirements of Prac
40、tice 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 andcooling in a
41、 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 room temper
42、ature 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 than 0.2 mg,
43、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 samples whi
44、ch 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 of observedva
45、lues, 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 nearestsignificant plac
46、e 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 reference test m
47、ethods 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 b
48、e 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 methods. Excep-tion can be made when specific test
49、 methods are prescribed inthe standard specification for the limestone, quicklime, orhydrated lime in question. The test methods actually used forthe analysis shall be designated.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeia Convention, Inc. (USPC), Rockville,MD.C2
