1、Designation: C471M 01 (Reapproved 2012)Standard Test Methods forChemical Analysis of Gypsum and Gypsum Products(Metric)1This standard is issued under the fixed designation C471M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the chemical analysis ofgypsum and gypsum products, including gypsum ready-mixedplast
3、er, gypsum wood-fibered plaster and gypsum concrete.1.2 The test methods appear in the following order:SectionsAlternative Procedure for Analysis for Calcium Sulfate by AmmoniumAcetate Method 17-22Alternative Procedure for Analysis for Sodium Chloride by the Coulo-metric Method 23-29Complete Procedu
4、re 5-16Determination of Sand in Set Plaster 30-36Optional Procedure for Analysis for Sodium by Flame Photometry 47-54Optional Procedure for Analysis for Sodium by the Atomic Absorp-tion Method 40-46Preparation of Sample 4Wood-Fiber Content in Wood-Fiber Gypsum Plaster 37-391.3 The text of this stand
5、ard references notes and footnotesthat provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the standard.1.4 The values stated in SI units are to be regarded as thestandard.1.5 This standard does not purport to addre
6、ss 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.2. Referenced Documents2.1 ASTM Standards:2C11 Terminology
7、 Relating to Gypsum and Related BuildingMaterials and SystemsC22/C22M Specification for GypsumC28/C28M Specification for Gypsum PlastersC59 Specification for Gypsum Casting Plaster and GypsumMolding PlasterC61 Specification for Gypsum Keenes CementC317/C317M Specification for Gypsum ConcreteC842 Spe
8、cification for Application of Interior GypsumPlasterD1193 Specification for Reagent WaterD1428 Methods of Test for Sodium and Potassium in Waterand Water-Formed Deposits by Flame Photometry3D2013 Practice for Preparing Coal Samples for AnalysisE11 Specification for Woven Wire Test Sieve Cloth and Te
9、stSieves3. Terminology3.1 DefinitionsDefinitions shall be in accordance withTerminology C11.3.2 Definitions of Terms Specific to This Standard:3.2.1 sample as received, na representative portion of rawgypsum or gypsum product in the state received by the testinglaboratory, including aggregates, impu
10、rities and water content.3.2.2 dried sample, na sample devoid of free water.3.2.3 riffle, na hand feed sample divider device thatdivides the sample into parts of approximately the sameweight. (D2013)4. Preparation of Sample4.1 General ProceduresDetails of sample preparationwill vary according to the
11、 type of material being tested.4.1.1 Sample As ReceivedUse a sufficient amount ofsample such that, after sieving, not less than 50 g of samplewill remain for testing. Weigh the entire sample immediatelyafter opening the container in which the material was received.This will become the weight of the
12、sample as received.4.1.2 DryingDry the sample in accordance with Section7. This will be the weight of the dried sample.4.1.3 Crushing and GrindingCrush and grind the sampleby hand with a mortar and pestle or by mechanical crushingand grinding equipment to pass a 250-m (No. 60) sieve. Takecare, parti
13、cularly with mechanical equipment, not to expose thesample to temperatures of more than 52 C. Clean the1These test methods are under the jurisdiction of ASTM Committee C11 onGypsum and Related Building Materials and Systems and are the direct responsi-bility of Subcommittee C11.01 on Specifications
14、and Test Methods for GypsumProducts.Current edition approved June 1, 2012. Published July 2012. Originally approvedin 1961. Last previous edition approved in 2006 as C471 01 (2006)1. DOI:10.1520/C0471M-01R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custome
15、r Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO B
16、ox C700, West Conshohocken, PA 19428-2959, United States.equipment thoroughly between samples. Thoroughly remix theground sample and store it in an airtight container to avoidcontamination.4.1.4 RehydratingThoroughly blend and rehydratesamples which contain calcium sulfate in forms other thanCaSO42H
17、2O and natural anhydrite. Place the sample indistilled water and keep it wet for not less than 48 h. Dry thehydrated sample in an oven at 45 6 3 C to constant weightand recrush or grind it in accordance with 4.1.3.4.1.5 Sample ReductionThoroughly mix and reduce largesamples as required by quartering
18、 or by the use of a riffle toobtain a specimen of approximately 50 g.4.2 Gypsum (C22/C22M)Gypsum samples will be re-ceived in the form of rocks, powder or both. If necessary crushand reduce the entire dried sample in accordance with 4.1.3 and4.1.5.4.3 Gypsum Plaster,(C28/C28M).4.3.1 Gypsum Ready-Mix
19、ed Plaster or Gypsum WoodFi-bered PlasterScreen the dried sample through a 150-m (No.100) sieve4and discard the residue retained on the sieve.Reweigh the remaining sample and calculate the percentage ofthe dried sample. Reduce the sample in accordance with 4.1.5.Thoroughly blend and rehydrate the sp
20、ecimen in accordancewith 4.1.4.4.3.2 Gypsum Neat Plaster or Gypsum Gauging PlasterReduce the dried sample in accordance with 4.1.5. Thoroughlyblend and rehydrate the specimen in accordance with 4.1.4.4.4 Gypsum Casting and Molding Plaster , (C59)Reducethe dried sample in accordance with 4.1.5. Thoro
21、ughly blendand rehydrate the specimen in accordance with 4.1.4.4.5 Gypsum Keenes Cement, (C61)Reduce the driedsample in accordance with 4.1.5. Blend in no more than 1 %molding plaster or K2SO4and rehydrate the specimen inaccordance with 4.1.4.4.6 Gypsum Concrete, (C317/C317M)Screen the driedsample t
22、hrough a 150-m (No. 100) sieve4and discard theresidue retained on the sieve. Reweigh the remaining sampleand calculate the percentage of the dried sample. Reduce thesample in accordance with 4.1.5. Thoroughly blend and rehy-drate the specimen in accordance with 4.1.4.4.7 Gypsum BoardCut or break the
23、 dried sample intosmall pieces. Using a mortar and pestle, strike the pieces of thesample to loosen the paper face. Remove the pieces of paper byhand as they are separated from the core of the gypsum board.Carefully scrape any remaining powder from the paper. Whenall the paper has been removed from
24、the pieces of the sample,reduce the sample in accordance with 4.1.5. Thoroughly blendand rehydrate the specimen in accordance with 4.1.4.COMPLETE PROCEDURE5. Apparatus5.1 Analytical BalanceCapable of weighing the weighingbottles, lids and samples.5.2 BalanceCapable of weighing not less than 100 g at
25、 aprecision of 0.001 g.5.3 Drying OvenA mechanical convection oven set at 456 3 C.5.4 DesiccatorCapable of being tightly sealed and con-taining calcium chloride or equivalent desiccant.5.5 Calcining Oven or FurnaceCapable of achieving andmaintaining temperatures to not less than 1000 C.5.6 Weighing
26、BottlesBorosilicate glass or ceramic con-tainers with tightly sealable lids.5.7 Hot PlateA controllable hot plate capable of heatingcasseroles to approximately 120 C.5.8 Porcelain CasserolesWith a capacity of 50 to 100 mL.5.9 Filtering Funnels.5.10 Filter Paper.5.11 Porcelain Crucibles.5.12 Mortar a
27、nd Pestle.5.13 Mechanical Jaw CrusherCapable of crushing gyp-sum rocks up to 50 mm diameter.5.14 Mechanical GrinderBurr mill or equivalent capableof grinding the granular output of the jaw crusher specified in5.13.6. Reagents6.1 Purity of ReagentsUse reagent grade chemicals in alltests. Unless other
28、wise indicated, use reagents that conform tothe specifications of the Committee on Analytical Reagents ofthe American Chemical Society, where such specifications areavailable.5If it is necessary to use other grades first ascertainthat the reagent is of sufficiently high purity so that its use willno
29、t lessen the accuracy of the determination.6.1.1 Ammonium Chloride (NH4Cl).6.1.2 Ammonium Hydroxide (sp gr 0.90)Concentratedammonium hydroxide (NH4OH).6.1.3 Ammonium Nitrate (25 g/L)Dissolve 25 g of am-monium nitrate (NH4NO3) in water and dilute to 1 L.6.1.4 Ammonium Oxalate (NH4)2C2O4).6.1.5 Barium
30、 Chloride (100 g/L)Dissolve 100 g ofbarium chloride (BaCl22H2O) in water and dilute to 1 L.6.1.6 Calcium Chloride (CaCl2)Anhydrous CalciumChloride with a combined water of not more than 5 %.6.1.7 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).6.1.8 Hydrochloric Acid (1 + 4)Mix 1
31、 volume of HCl (spgr 1.19) with 4 volumes of water.6.1.9 Hydrochloric Acid (1 + 5)Mix 1 volume of HCl (spgr 1.19) with 5 volumes of water.6.1.10 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3).6.1.11 Potassium Chromate Solution (100 g/L)Dissolve 5g of potassium chromate (K2CrO4) in 50 mLof wa
32、ter, mix, add10 drops of 0.05 N silver nitrate (AgNO3) solution, allow tostand for 5 min, and filter.4Detailed requirements for this sieve are given in Specification E11.5Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the te
33、sting 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. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.C471M 01 (2012)26.1.12 Potassium Permanganate
34、(5.6339 g/L)Dissolve5.6339 g of potassium permanganate (KMnO4) in water anddilute to 1 L.6.1.13 Silver Nitrate, Standard Solution (0.05 N)Prepareand standardize a 0.05 N silver nitrate (AgNO3) solution.6.1.14 Sodium Ammonium Phosphate(NaNH4HPO4).6.1.15 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric
35、acid (H2SO4).6.1.16 Sulfuric Acid (1 + 6)Carefully mix 1 volume ofH2SO4(sp gr 1.84) with 6 volumes of water.6.1.17 Nitric Acid (0.1 N)Mix 1.4 mL of HNO3(sp gr1.42) with 200 mL of water.6.1.18 Phenolphthalein Indicator Solution Dissolve 0.25g of phenolphthalein in 30 mL of methanol and dilute to 50 m
36、Lwith water.6.1.19 Sodium Hydroxide Solution (0.1 N)Dissolve1gofsodium hydroxide (NaOH) in 250 mL of water.6.1.20 WaterReagent water shall be in accordance withSpecification D1193, type II. Specification D1193 gives thefollowing values for type II grade water.Electrical conductivity, max, S/cm at 29
37、8 K (25-C) 1.0Electrical resistivity, min, MVcm at 298 K (25-C) 1.0Total organic carbon (TOC), max, g/L 50.0Sodium, max, g/L 5.0Chlorides max, g/L 5.0Total silica, max, g/L 5.07. Free Water7.1 Significance and UseThe free water analysis deter-mines the amount of free water contained in the sample as
38、opposed to chemically combined water, and prepares thesample for further analysis.7.2 Procedure:7.2.1 Weigh a sample of the material as received of not lessthan 50 g to a precision of 0.001 g and spread it out in a thinlayer in a suitable vessel. Place in an oven and dry at 45 6 3C for 2 h, then coo
39、l in a desiccator and weigh again. The lossof weight corresponds to the free water.7.2.2 Retain the sample in a sealed container or in thedesiccator for further analysis.7.3 Calculation and ReportCalculate and report loss inweight as a percentage of the sample as received or of the driedsample as re
40、quired.7.4 Precision and BiasNeither the precision nor the biasfor the free water analysis has been determined.8. Combined Water8.1 Significance and UseThe combined water analysisdetermines the percent of chemically combined water and isused to calculate the purity of gypsum or the amount ofgypsum o
41、r gypsum plaster in gypsum products.8.2 InterferencesSome materials, such as organic andhydrated compounds that decompose within the same tempera-ture range as gypsum, will cause high results. When themaximum temperature is exceeded, some carbonates undergodecomposition, which will result in high re
42、sults.8.3 Procedure:8.3.1 For each sample, place three weighing bottles withlids in the preheated calcining oven or furnace and heat for 2h at 215 to 230 C. Place in the desiccator and allow to cool toroom temperature. Weigh the bottles and lids to the nearest0.0001 g and record the tare weights.8.3
43、.2 Weigh out three specimens of approximately 1 g eachof the sample as prepared in Section 4 and dried in Section 7to a precision of 0.0001 g in the previously tared weighingbottles and record the total weight with lids.8.3.3 Place the specimens in the calcining oven with the lidsplaced loosely on e
44、ach bottle or crucible for2horuntilconstant weight has been obtained.8.3.4 Place the lids tightly on the weighing bottles, removefrom the oven, and place in the desiccator to cool to roomtemperature.8.3.5 Weigh each specimen to a precision of 0.0001 g andrecord the weights.8.3.6 Retain the residues
45、for carbon dioxide analysis.8.4 Calculation and ReportCalculate and report the aver-age loss in weight of the three specimens as a percentage of thesample as received or of the dried sample, as required, to thenearest 0.001 g and record the tare weights.8.5 Precision and BiasNeither the precision no
46、r the biasfor the combined water analysis has been determined.9. Carbon Dioxide9.1 Summary of Test MethodThe sample is decomposedwith HCl and the liberated CO2is passed through a series ofscrubbers to remove water and sulfides. The CO2is absorbedwith Ascarite, a special sodium hydroxide absorbent, a
47、nd thegain in weight of the absorption tube is determined andcalculated as percent CO2.9.2 Significance and UseThe carbon dioxide analysis isuseful in estimating carbonates and organic carbon for chemi-cal balance.9.3 Special Reagents:9.3.1 Magnesium Perchlorate Desiccantfor drying.9.3.2 Sodium Hydr
48、oxide Absorbenta coarse sodium hy-droxide coated silica.9.4 Special ApparatusThe apparatus illustrated in Fig. 1consists of the following:9.4.1 Purifying Jar A, Fleming, containing sulfuric acid.9.4.2 Drying Tube B, U-shaped with side arms and glass-stoppers. Side arms are shaped to hold rubber tubi
49、ng. ContainsAnhydrone on left side and Ascarite on right side.9.4.3 Erlenmeyer Flask C, 250 mL, 24/20 ground-glassjoint.9.4.4 Separatory Funnel D, with ground glass stopper andinterchangeable hollow ground-glass joint. A delivery tubebent at the end extends into the sample flask approximately 15mm from the bottom and is used to introduce acid into flask.9.4.5 Condenser E.9.4.6 Gas-Washing Bottle F, 250 mL, with fitted diskcontaining distilled water to retain most of the acid volatilizedfrom the alkalimet
