1、Designation: C471M 16Standard 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 year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods cover the chemical analysis ofgypsum and gypsum panel products, including gypsum ready-mixed plaster, gypsum
3、 wood-fibered plaster, and gypsumconcrete.1.2 The test methods appear in the following order:SectionsPreparation of Sample 4Complete Procedure 516Alternative Procedure for Analysis ofFree Water in Gypsum Using a Mois-ture Balance17Alternative Procedure for Analysis ofCombined Water in Gypsum Using a
4、Moisture Balance18Alternative Procedure for Analysis forCalcium Sulfate by Ammonium AcetateMethod19Alternative Procedure for Analysis forSodium Chloride by the CoulometricMethod20Determination of Sand in Set Plaster 21Wood-Fiber Content in Wood-Fiber Gyp-sum Plaster22Optional Procedure for Analysis
5、for So-dium by the Atomic Absorption Method23Optional Procedure for Analysis for So-dium by Flame Photometry24Determination of Orthorhombic Cyclooc-tasulfur (S8) in Ggypsum PanelProductsGeneral Provisions25Determination of Orthorhombic Cyclooc-tasulfur (S8) in Gypsum Panel Prod-ucts by Gas Chromatog
6、raph Equippedwith a Mass Spectrometer (GS/MS)26Determination of Orthorhombic Cyclooc-tasulfur (S8) in Gypsum Panel Prod-ucts by Gas Chromatograph Equippedwith an Electron Capture Detector(GC/ECD)27Determination of Orthorhombic Cyclooc-tasulfur (S8) in Gypsum Panel Prod-ucts by High-performance Liqui
7、d Chro-matograph Equipped with andUltraviolet Detector (HPLC/UV)281.3 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 consideredas requirements of the standard.1.4 The values stat
8、ed 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 safety and health practices and determine the applica-bility of re
9、gulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C11 Terminology Relating to Gypsum and Related BuildingMaterials and SystemsC22/C22M Specification for GypsumC28/C28M Specification for Gypsum PlastersC59 Specification for Gypsum Casting Plaster and GypsumMolding PlasterC6
10、1 Specification for Gypsum Keenes CementC317/C317M Specification for Gypsum ConcreteC778 Specification for Standard SandC842 Specification for Application of Interior Gypsum Plas-terD1193 Specification for Reagent WaterD1428 Test Method for Test for Sodium and Potassium InWater and Water-Formed Depo
11、sits by Flame Photometry(Withdrawn 1989)3D2013 Practice for Preparing Coal Samples for AnalysisE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 DefinitionsDefinitions shall be in accordance withTerminology C11.1These test methods are under the jurisdiction of ASTM Co
12、mmittee 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.Current edition approved Jan. 1, 2016. Published January 2016. Originallyapproved in 1961. Last previous edition approved in
13、 2014 as C471 14. DOI:10.1520/C0471M-16.2For referenced ASTM standards, 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.3The last approved ve
14、rsion of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 Definitions:3.2.1 calibration standard, na chemical mi
15、xture contain-ing a known quantity of the analyte used to relate the measuredanalytical signal to the concentration of the analyte.3.2.2 dried sample, na sample devoid of free water.3.2.3 internal standard, na chemical used in the quantifi-cation of S8by monitoring and adjusting for minor variances
16、ininstrument performance.3.2.4 riffle, na hand feed sample divider device thatdivides the sample into parts of approximately the sameweight. (D2013)3.2.5 sample as received, na representative portion of rawgypsum or gypsum product in the state received by the testinglaboratory, including aggregates,
17、 impurities and water content.3.2.6 surrogate standard, na chemical used to account forextraction efficiency of S8.4. Preparation of Sample4.1 General ProceduresDetails of sample preparation willvary according to the type of material being tested.4.1.1 Sample As ReceivedUse a sufficient amount ofsam
18、ple 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 sample as received.4.1.2 DryingDry the sample in accordance with 7. Thiswill be the
19、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, particularly with mechanical equipment, not to expose thesample to temperatures of more than 52C.
20、 Clean the equip-ment 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 thanCaSO42H2O and natural anhydrite. Place the sample in
21、distilled water and keep it wet for not less than 48 h. Dry thehydrated sample in an oven at 45 6 3C to constant weight andrecrush or grind it in accordance with 4.1.3.4.1.5 Sample ReductionThoroughly mix and reduce largesamples as required by quartering or by the use of a riffle toobtain a specimen
22、 of approximately 50 g.4.2 Gypsum (C22/C22M)Gypsum samples will be re-ceived in the form of rocks or powder, or both. If necessarycrush and reduce the entire dried sample in accordance with4.1.3 and 4.1.5.4.3 Gypsum Plaster, (C28/C28M).4.3.1 Gypsum Ready-Mixed Plaster or Gypsum WoodFi-bered PlasterS
23、creen 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 specimen in accordancewith 4.1.44.3.2 Gypsum
24、 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. Thoroughly blendand rehydrate the specimen in acco
25、rdance 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 through a 150-m (No. 100) sieve4and discard ther
26、esidue 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 4.1.44.7 Gypsum Panel ProductsCut or break the dried sampleinto small pieces. Using a
27、 mortar and pestle, strike the piecesof the sample to loosen the paper face. Remove the pieces ofpaper by hand as they are separated from the core of thegypsum board. Carefully scrape any remaining powder fromthe paper. When all the paper has been removed from thepieces of the sample, reduce the sam
28、ple in accordance with4.1.5.COMPLETE PROCEDURE5. Apparatus5.1 Analytical BalanceCapable of weighing the weighingbottles, lids and samples.5.2 BalanceCapable of weighing not less than 100 g at aprecision of 0.001 g.5.3 Drying OvenA mechanical convection oven set at 456 3C.5.4 DesiccatorCapable of bei
29、ng tightly sealed and con-taining calcium chloride or equivalent desiccant.5.5 Calcining Oven or FurnaceCapable of achieving andmaintaining temperatures to not less than 1000C.5.6 Weighing BottlesBorosilicate glass or ceramic con-tainers with tightly sealable lids.5.7 Hot PlateA controllable hot pla
30、te capable of heatingcasseroles to approximately 120C.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 and Pestle.5.13 Mechanical Jaw CrusherCapable of crushing gyp-sum rocks up to 50 mm diameter.4Detailed requiremen
31、ts for this sieve are given in Specification E11.C471M 1625.14 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 otherwise indicated, use reagents that
32、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 willnot lessen the accuracy of the dete
33、rmination.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 ammo-nium nitrate (NH4NO3) in water and dilute to 1 L.6.1.4 Ammonium Oxalate (NH4)2C2O4).6.1.5 Barium Chloride (100 g/L)Dissolve 100 g
34、 of bariumchloride (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 volume of HCl (spgr 1.19) with 4 v
35、olumes 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)Dissolve5 g of potassium chromate (K2CrO4) in 50 mL of water, mix,add 10 drops of 0.05 N silv
36、er nitrate (AgNO3) solution, allowto stand for 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
37、.14 Sodium Ammonium Phosphate(NaNH4HPO4).6.1.15 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
38、 Indicator SolutionDissolve 0.25 gof phenolphthalein 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 D1193, type II. Specification D119
39、3 gives thefollowing values for type II grade water.Electrical conductivity, max, S/cm at 298 K (25-C) 1.0Electrical resistivity, min, Mcm 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
40、 UseThe free water analysis deter-mines 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
41、 in a thinlayer in a suitable vessel. Place in an oven and dry at 45 6 3Cfor 2 h, then cool in a desiccator and weigh again. The loss ofweight 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
42、report loss inweight as a percentage 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 chemi
43、cally combined water and isused to calculate 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 t
44、emperature is exceeded, some carbonates 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 2 hat 215 to 230C. Place in the desiccator and allow to cool toroom tempe
45、rature. Weigh the bottles and lids to 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 4and dried in Section 7toa precision of 0.0001 g in the previously tared weighing bottlesand record the total weight wit
46、h lids.8.3.3 Place the specimens in 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 ea
47、ch specimen to a precision of 0.0001 g andrecord the weights.8.3.6 Retain the residues for carbon dioxide analysis.5Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical So
48、ciety, 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 1638.4 Calculation and ReportCalculate and report the aver-age loss in weight of the three spec
49、imens 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 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 absorbedwith Ascarite, a special sodium hydroxide absorbent, and thegain in weight of th
