ASTM D3897-1991(2012) Standard Practice for Calculation of Basicity of Chrome Tanning Liquors 《铬鞣液碱性值计算的标准实施规程》.pdf

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1、Designation: D3897 91 (Reapproved 2012)Standard Practice forCalculation of Basicity of Chrome Tanning Liquors1This standard is issued under the fixed designation D3897; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la

2、st 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 practice is intended to show how the results of thechromium analysis (Test Method D3898) and the aciditydeterminati

3、on (Test Method D3913) can be combined to permitcalculation of the basicity of a chrome tanning liquor.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,

4、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:2D3898 Test Method for Chromic Oxide in Basic

5、ChromiumTanning LiquorsD3913 Test Method for Acidity in Basic Chromium Tan-ning Liquors3. Significance and Use3.1 Basicity is a ratio. In any chromic salt solution, theelectrovalence of the chromium (+3) is satisfied by the hy-droxyl ions and by acid ions. The extent to which thiselectravalence is s

6、atisfied by the hydroxyl ions, expressed as apercentage, is the basicity. The basicity of a chrome tanningliquid is closely related to the tanning behavior of the solution.4. Procedure4.1 Determine the chromic oxide as described in TestMethod D3898. Determine the acid as described in TestMethod D391

7、3.5. Results5.1 The basicity of the liquor shall be expressed accordingto the Schorlemmer system. In this system, the basicity is theper cent of the total chromic oxide that is combined withhydroxyl and is calculated as follows:Basicity, % 5A 2 BA3 100 (1)where:A = the amount of thiosulfate, as mL o

8、f 0.1 N solutionrequired to titrate the 25 mL aliquot as the specimen inTest Method D3898,B = the amount of sodium hydroxide, as mL of 0.1 Nsolution required to titrate the 25 mL aliquot of thespecimen in Test Method D3913.6. Precision and Bias6.1 Because basicity is in effect a ratio, the precision

9、indexes are transmitted by the laws governing ratios. If theprecision of accuracy of the chromic oxide determination or ofthe titratable acidity is expressed in the same relative units; forexample, percent of value being determined, the precision withwhich the basicity is known will be:PB5=PCR21 PA2

10、(2)where:PA= precision of acidity in basic chromium tanningliquors,PCR= precision of chromic oxide in basic chromiumtanning liquors,PB= precision of basicity in basic chromium tanningliquors.6.2 For the reported reproducibility figures for the chromicoxide from Test Method D3898 (d = 0.90 %) and for

11、 acidityfrom Test Method D3913 (Procedure I, s = 1.84 %), dBisgiven as 2.05 %. This number has the units of basicity.Similarly, repeatability has d = 0.52 % basicity. Caution shouldbe employed in insisting on extremely close agreements1This practice is under the jurisdiction ofASTM Committee D31 on

12、Leather andis the direct responsibility of Subcommittee D31.06 on Chemical Analysis.Current edition approved April 1, 2012. Published April 2012. Originallyapproved in 1991. Last previous edition approved in 2006 as D3897 - 91(2006).DOI: 10.1520/D3897-91R12.2For referenced ASTM standards, visit the

13、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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Un

14、ited States.between laboratories or replicates unless a background of highprecision has been established.37. Keywords7.1 basicity; chrome tanning liquor; SchorlemmerASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this

15、 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

16、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 should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of therespo

17、nsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, Wes

18、t Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).3Hartford, W. H., The Journal of the Leather Chemists Assoc., Vol 56, 1961, p.568.D3897 91 (2012)2