ASTM_D_934_-_13.pdf

Designation:D93413Standard Practices forIdentification of Crystalline Compounds in Water-FormedDeposits By X-Ray Diffraction1This standard is issued under the fixed designation D934;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the 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 practices provide for X-ray diffraction analysis ofpowdered crystalline compounds in water-formed deposits.Two are given as follows:SectionsPractice ACamera12 to 21Practice BDiffractometer22 to 301.2 Both practices yield qualitative identification of crystal-line components of water-formed deposits for which X-raydiffraction data are available or can be obtained.Greaterdifficulty is encountered in identification when the number ofcrystalline components increases.1.3 Amorphous phases cannot be identified without specialtreatment.Oils,greases,and most organic decompositionproducts are not identifiable.1.4 The sensitivity for a given component varies with acombinationofsuchfactorsasdensity,degreeofcrystallization,particle size,coincidence of strong lines ofcomponents and the kind and arrangement of the atoms of thecomponents.Minimum percentages for identification maytherefore range from 1 to 40%.1.5 The values stated in SI units are to be regarded asstandard.The values listed in parenthesis are for informationonly.1.6 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 consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.Specific precautionary statements are given in Section 8 andNote 20.2.Referenced Documents2.1 ASTM Standards:2D887 Practices for Sampling Water-Formed DepositsD933 Practice for Reporting Results of Examination andAnalysis of Water-Formed DepositsD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2331 Practices for Preparation and Preliminary Testing ofWater-Formed DepositsE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3.Terminology3.1 For definitions of terms used in these practices,refer toTerminology D1129.4.Summary of Practices4.1 Powdered samples are irradiated with a monochromaticX-ray beam of short wavelength(from about 0.05 to 0.25 nm).The X rays interact with the atoms in the crystal and arescattered in a unique diffraction pattern which produces afingerprint of the crystals atomic or molecular structure.Theanalytical instrumentation used in X-ray diffraction includesthe powder camera and the diffractometer(1-5).35.Significance and Use5.1 The identification of the crystalline structures in water-formed deposits assists in the determination of the depositsources and mode of deposition.This information may lead tomeasures for the elimination or reduction of the water-formeddeposits.6.Purity of Reagents6.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated,it is intended that all reagents shallconform to the specifications of the Committee on Analytical1These practices are under the jurisdiction of ASTM Committee D19 on Waterand are the direct responsibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits,Analysis of Water for Power Generation and Process Use,On-Line Water Analysis,and Surveillance of Water.Current edition approved Jan.1,2013.Published February 2013.Originallyapproved in 1947.Last previous edition approved in 2008 as D934 08.DOI:10.1520/D0934-13.2For 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 boldface numbers in parentheses refer to the references listed at the end ofthese practices.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 Reagents of the American Chemical Society,where suchspecifications are available.4Other grades may be used,pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterReference to water that is used forreagent preparation,rinsing or dilution shall be understood tomean water that conforms to the quantitative specifications ofType I or II reagent water of SpecificationD1193.7.Sampling7.1 Collect the sample in accordance with Practices D887.7.2 A suitable amount of sample should be obtained so thatit is representative of the deposit under investigation.7.3 Deposits shall be removed and protected in such a waythat they remain as nearly as possible in their original states.8.Safety Precautions8.1 The potential danger of high-voltage and X-ray radia-tio