1、Designation: C 471M 01 (Reapproved 2006)e1METRICStandard Test Methods forChemical Analysis of Gypsum and Gypsum ProductsMetric1This standard is issued under the fixed designation C 471M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTENote 1 and certain footnotes were removed editorially to conform to ASTM Form and Style requirements for so
3、lesource of supply January 2007.1. Scope1.1 These test methods cover the chemical analysis ofgypsum and gypsum products, including gypsum ready-mixedplaster, gypsum wood-fibered plaster and gypsum concrete.1.2 The test methods appear in the following order:SectionsAlternative Procedure for Analysis
4、for Calcium Sulfate by AmmoniumAcetate Method 17-22Alternative Procedure for Analysis for Sodium Chloride by the Coulo-metric Method 23-29Complete Procedure 5-16Determination of Sand in Set Plaster 30-36Optional Procedure for Analysis for Sodium by Flame Photometry 47-54Optional Procedure for Analys
5、is 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 standard references notes and footnotesthat provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be
6、 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 address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safe
7、ty and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C11 Terminology Relating to Gypsum and Related Build-ing Materials and SystemsC 22/C 22M Specification for GypsumC 28/C 28M Specification for Gypsum PlastersC59
8、Specification for Gypsum Casting Plaster and GypsumMolding PlasterC61 Specification for Gypsum Keenes CementC 317/C 317M Specification for Gypsum ConcreteC 842 Specification for Application of Interior GypsumPlasterD 1193 Specification for Reagent WaterD 1428 Methods of Test for Sodium and Potassium
9、 in Waterand Water-Formed Deposits by Flame Photometry3D 2013 Practice for Preparing Coal Samples for AnalysisE11 Specification for Wire Cloth and Sieves for TestingPurposes3. Terminology3.1 DefinitionsDefinitions shall be in accordance withTerminology C11.3.2 Definitions of Terms Specific to This S
10、tandard:3.2.1 sample as received, na representative portion of rawgypsum or gypsum product in the state received by the testinglaboratory, including aggregates, impurities and water content.3.2.2 dried sample, na sample devoid of free water.3.2.3 riffle, na hand feed sample divider device thatdivide
11、s the sample into parts of approximately the sameweight. (D 2013)4. Preparation of Sample4.1 General ProceduresDetails of sample preparationwill vary according to the type of material being tested.4.1.1 Sample As ReceivedUse a sufficient amount ofsample such that, after sieving, not less than 50 g o
12、f samplewill remain for testing. Weigh the entire sample immediately1These 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 and Test Methods for GypsumProducts
13、.Current edition approved Dec. 1, 2006. Published January 2007. Originallyapproved in 1961. Last previous edition approved in 2001 as C 471 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards vo
14、lume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.after opening the container in which the material was received.This will become the weight o
15、f the 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,
16、 particularly with mechanical equipment, not to expose thesample to temperatures of more than 52 C. Clean theequipment thoroughly between samples. Thoroughly remix theground sample and store it in an airtight container to avoidcontamination.4.1.4 RehydratingThoroughly blend and rehydratesamples whic
17、h contain calcium sulfate in forms other thanCaSO42H2O 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 m
18、ix and reduce largesamples as required by quartering or by the use of a riffle toobtain a specimen of approximately 50 g.4.2 Gypsum (C 22/C 22M)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.
19、5.4.3 Gypsum Plaster, (C 28).4.3.1 Gypsum Ready-Mixed 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 accordan
20、ce with 4.1.5.Thoroughly blend and rehydrate the specimen 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 , (C 59)Re
21、ducethe dried sample in accordance with 4.1.5. Thoroughly blendand rehydrate the specimen in accordance with 4.1.4.4.5 Gypsum Keenes Cement, (C 61)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
22、Gypsum Concrete, (C 317)Screen the dried samplethrough a 150-m (No. 100) sieve4and discard the residueretained on the sieve. Reweigh the remaining sample andcalculate the percentage of the dried sample. Reduce thesample in accordance with 4.1.5. Thoroughly blend and rehy-drate the specimen in accord
23、ance with 4.1.4.4.7 Gypsum BoardCut or break the 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
24、 paper. Whenall the paper has been removed from 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 B
25、alanceCapable of weighing not less than 100 g at 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 te
26、mperatures to not less than 1000 C.5.6 Weighing 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 Fil
27、ter Paper.5.11 Porcelain Crucibles.5.12 Mortar and 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 r
28、eagent grade chemicals in alltests. Unless otherwise 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
29、 sufficiently high purity so that its use willnot 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
30、.6.1.4 Ammonium Oxalate (NH4)2C2O4).6.1.5 Barium 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
31、 acid (HCl).4Detailed requirements for this sieve are given in Specification E11.5Reagent 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 La
32、boratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.C 471M 01 (2006)e126.1.8 Hydrochloric Acid (1 + 4)Mix 1 volume of HCl (spgr 1.19) with 4 volumes of water.6.1.9 Hydrochloric Acid (1 +
33、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 water, mix, add10 drops of 0.05 N silver nitrate (AgNO3) solution, allow tostand f
34、or 5 min, and filter.6.1.12 Potassium Permanganate (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
35、.15 Sulfuric Acid (sp gr 1.84)Concentrated sulfuricacid (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 phen
36、olphthalein in 30 mL of methanol and dilute to 50 mLwith 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 D 1193, type II. Specification D 1193 gives thefollowing values for type II
37、 grade water.Electrical conductivity, max, S/cm at 298 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-mine
38、s the amount of free water contained in the sample asopposed 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.
39、Place in an oven and dry at 45 6 3C for 2 h, then cool 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
40、of the sample as received or of the driedsample as required.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 ca
41、lculate the purity of gypsum or the amount ofgypsum or 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 carbonat
42、es undergodecomposition, which will result in high results.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 t
43、o the nearest0.0001 g and record the tare weights.8.3.2 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 i
44、n the calcining oven with the lidsplaced loosely on each 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 0.00
45、01 g andrecord the weights.8.3.6 Retain the residues 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 w
46、eights.8.5 Precision and BiasNeither the precision nor 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 absorbedw
47、ith Ascarite, a special sodium hydroxide absorbent, and 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 Magnes
48、ium Perchlorate Desiccantfor drying.9.3.2 Sodium Hydroxide 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 gla
49、ss-stoppers. Side arms are shaped to hold rubber tubing. 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.C 471M 01 (2006)e139.4.5 Condenser E.9.4.6 Gas-Washing Bottle F, 250 mL, with fitted diskcontaini
