ASTM_D_4654_-_87_2020.pdf

Designation:D465487(Reapproved 2020)Standard Test Method forSulfate Basicity in Leather1This standard is issued under the fixed designation D4654;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 This test method is intended for use in calculating thesulfate basicity of mineral tanned leather.1.2 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D2807 Test Method for Chromic Oxide in Leather(Perchlo-ric Acid Oxidation)D4655 Test Methods for Sulfates in Leather(Total,Neutral,and Combined Acid)3.Significance and Use3.1 This test method is used to determine the percent of totalchromic oxide that is combined with hydroxyl and may serveas a measure of chrome fixation.4.Apparatus and Reagents4.1 The apparatus and reagents shall be as described in TestMethods D2807 and D4655.5.Sampling,Test Specimens and Test Units5.1 The test specimen shall be as described in Test MethodsD2807 and D4655.5.2 Unless otherwise specified in the detail specifications,two specimens from the composite sample shall be tested.5.3 The percent basicity of the sample for test shall be theaverage of the test results obtained from the specimens tested.6.Procedure6.1 The chromic oxide shall be determined as described inTest Method D2807.The combined sulfate shall be determinedas described in Method D4655.7.Calculation of Results7.1 Express the percent basicity of the specimen accordingto Schorlemmers system.In this system,the percent basicity isthe percent of the total chromic oxide that is combined withhydroxyl.Conversely,the percent acidity is the percent of thetotal chromic acid that is combined with sulfate or other acidanions.Percent basicity is therefore 100%acidity.sulfate basicity,%5 1002%combined sulfate352.8/%total chromic oxide(1)7.2 When other metals that form hydrolysable sulfates arepresent,add their equivalent percent of chromic oxide to thechromic oxide present before calculating percent basicity.Usethefollowingconversionfactors:%Al2O3 1.49,%ZrO2 0.82,and%Fe2O3 0.95.7.3 Report the results to the nearest 0.1%.8.Precision and Bias8.1 This test method is adopted from the procedures of theAmerican Leather ChemistsAssociation where it has long beenin use and where it was approved for publication before theinclusion of precision and bias statements were mandated.Theoriginal inter-laboratory test data is no longer available.Theuser is cautioned to verify by the use of reference material ifavailable that the precision and bias of this test method isadequate for the contemplated use.9.Keywords9.1 chrome fixation;Schorlemmers system;sulfate basicity1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.06 on Chemical Analysis.Current edition approved April 1,2020.Published April 2020.Originallyapproved in 1987.Last previous edition approved in 2015 as D4654 87(2015).DOI:10.1520/D4654-87R20.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.Users of this standard are expressly advised that determination of the validity of any such patent rights,and the riskof infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand sh