ASTM_D_6716_-_08_2013.pdf

Designation:D671608(Reapproved 2013)Standard Test Method forTotal Ash in Wet Blue or Wet White1This standard is issued under the fixed designation D6716;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 covers the determination of total ash inwet blue and wet white.1.2 For total ash in wet white,the procedure is identical;substitute wet white for wet blue in the standard.1.3 Total ash in wet blue may be reported upon a number ofdifferent bases(for example,fat-free,moisture-free,asreceived,excluding chromium,and so forth).Before proceed-ing with any tests,it is very important to determine upon whichbasis that the total ash is to be reported and to identify all othertest methods that will be required to be executed in order toachieve the determined reporting method.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D3495 Test Method for Hexane Extraction of LeatherD6658 Test Method for Volatile Matter(Moisture)of WetBlue by Oven DryingD6659 Practice for Sampling and Preparation of Wet Bluefor Physical and Chemical TestsD6714 Test Method for Chromic Oxide in Ashed Wet Blue(Perchloric Acid Oxidation)3.Terminology3.1 Definitions:3.1.1 The terms and definitions employed within this testmethod are commonly used in normal laboratory practice andrequire no special comment.4.Summary of Test Method4.1 The weighed sample is ignited in air at 600 6 25C untilconstant mass is attained.The weighed residual matter istermed“ash”and is calculated as a percentage of the originalsample.5.Significance and Use5.1 This test method is useful in determining the approxi-mate amount of nonvolatile inorganic material in wet blue.This may be in the form of salts or oxides of the elements.Ina mixed-chrome tannage,the approximate percentage of otherelements in the wet blue may be determined by subtracting thechromic oxide that may be conveniently determined on the ash.(See Test Method D6714.)5.2 The specified temperature of 600C is high enough toproduce a reproducible result but it does not completelydehydrate such oxides as aluminum oxide(Al2O3)and chromicoxide(Cr2O3).Likewise,such salts as sulfates and phosphatesmay be incompletely dehydrated,and if alkalis and chromiumare present simultaneously,oxidation to chromate may occur.Therefore,caution is advised in drawing conclusions based onquantitative relations of the elements.6.Apparatus6.1 Crucible,30-to 50-mL,high-form,platinum or porce-lain.6.2 Electric Muffle Furnace,with controller or rheostat andpyrometer,capable of maintaining a temperature of 600 625C.6.3 Dessicator,of appropriate size and charged with freshdessicant.6.4 Analytical Balance,capable of accurate weighings towithin 0.001 g.7.Test Specimen7.1 The specimen shall consist of 2 to 10 g of wet blue fromthe composite sample,prepared in accordance with PracticeD6659.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.02 on Wet Blue.Current edition approved May 1,2013.Published May 2013.Originallyapproved in 2001.Last previous edition approved in 2008 as D6716 08.DOI:10.1520/D6716-08R13.2For 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 States1 NOTE1Typically,wet blue is a combination of organic hide substancein conjunction with inorganic chromium tanning salts.However,undersome circumstances,silicones or other solvent-soluble organo-metalliccomplexes(including electrolyte-stable fat liquors)are added duringmanufacture and may be present within the sample.It may be desirable tocalculate ash upon an extracted(fat free)basis,and if so,this should beindicated within the final report.To report ash upon an extracted basis,itwill be necessary to execute Test Method D3495 on a portion of the samesample and weighed out at the same time as the specimen for total ashdetermination.8.Procedure8.1 Weigh accurately into a tared crucible 2 to 10 g(60.001g)of wet blue,prepared as described in 7.1,and preferably atsufficiently close equilibrium with the laboratory humidity thatit does not gain or lose mass(moisture)at a significant ra