1、Designation: D3897 17D3897 18Standard Practice Test Method 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
2、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 practice is intended to show how the results of the chromium analysis (Test Methods D3898 or D6019) and the acidi
3、tydetermination (Test Method D3913) can be combined to permit calculation of the basicity of a chrome tanning liquor.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the
4、safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulatory limitations prior to use.1.4 This international standard was developed in accordanc
5、e with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standa
6、rds:2D3898 Test Method for Chromic Oxide in Basic Chromium Tanning LiquorsD3913 Test Method for Acidity in Basic Chromium Tanning LiquorsD6019 Test Method for Determination of Chromic Oxide in Basic Chromium Tanning Liquors (Ammonium PersulfateOxidation)3. Significance and Use3.1 Basicity is a ratio
7、. In any chromic salt solution, the electrovalence of the chromium (+3) is satisfied by the hydroxyl ionsand by acid ions. The extent to which this electravalence is satisfied by the hydroxyl ions, expressed as a percentage, is the basicity.The basicity of a chrome tanning liquid is closely related
8、to the tanning behavior of the solution.4. Procedure4.1 Determine the chromic oxide as described in Test Method D3898 or D6019. Determine the acid as described in Test MethodD3913.5. Results5.1 The basicity of the liquor shall be expressed according to the Schorlemmer system. In this system, the bas
9、icity is the percent of the total chromic oxide that is combined with hydroxyl and is calculated as follows:Basicity,%5A2BA 3100 (1)where:A = the amount of thiosulfate, as mL of 0.1 N solution required to titrate the 25 mL aliquot as the specimen in Test MethodsD3898 or D6019,B = the amount of sodiu
10、m hydroxide, as mL of 0.1 N solution required to titrate the 25 mL aliquot of the specimen in TestMethod D3913.1 This practice test method is under the jurisdiction of ASTM Committee D31 on Leather and is the direct responsibility of Subcommittee D31.06 on Chemical Analysis.Current edition approved
11、Sept. 1, 2017Sept. 1, 2018. Published October 2017October 2018. Originally approved in 1991. Last previous edition approved in 20122017 asD3897 - 91D3897(2012). -17. DOI: 10.1520/D3897-17.10.1520/D3897-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Se
12、rvice at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previ
13、ous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM Int
14、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Precision and Bias6.1 Because basicity is in effect a ratio, the precision indexes are transmitted by the laws governing ratios. If the precision ofaccuracy of the chromic oxide determination or of the
15、 titratable acidity is expressed in the same relative units; for example, percentof value being determined, the precision with which the basicity is known will be:PB5=PCR 21PA2 (2)where:PA = precision of acidity in basic chromium tanning liquors,PCR = precision of chromic oxide in basic chromium tan
16、ning liquors,PB = precision of basicity in basic chromium tanning liquors.6.2 For the reported reproducibility figures for the chromic oxide from Test Method D3898 ( = 0.90 %) and for acidity fromTest Method D3913 (Procedure I, = 1.84 %), B is given as 2.05 %. This number has the units of basicity.
17、Similarly, repeatabilityhas = 0.52 % basicity. Caution should be employed in insisting on extremely close agreements between laboratories or replicatesunless a background of high precision has been established.37. Keywords7.1 basicity; chrome tanning liquor; SchorlemmerASTM International takes no po
18、sition 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 responsibi
19、lity.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 should be addressed to AS
20、TM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible 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
21、 shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West 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
22、-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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ Scope1.1 This test method is intended to sho
23、w how the results of the chromium analysis (Test Methods D3898 or D6019) and theacidity determination (Test Method D3913) can be combined to permit calculation of the basicity of a chrome tanning liquor.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement a
24、re included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulato
25、ry limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organizat
26、ion Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D3898 Test Method for Chromic Oxide in Basic Chromium Tanning LiquorsD3913 Test Method for Acidity in Basic Chromium Tanning LiquorsD6019 Test Method for Determination of Chromic Oxide in Basic Chromium Tannin
27、g Liquors (Ammonium PersulfateOxidation)3. Significance and Use3.1 Basicity is a ratio. In any chromic salt solution, the electrovalence of the chromium (+3) is satisfied by the hydroxyl ionsand by acid ions. The extent to which this electravalence is satisfied by the hydroxyl ions, expressed as a p
28、ercentage, is the basicity.The basicity of a chrome tanning liquid is closely related to the tanning behavior of the solution.3 Hartford, W. H., The Journal of the Leather Chemists Assoc., Vol 56, 1961, p. 568.D3897 1824. Procedure4.1 Determine the chromic oxide as described in Test Method D3898 or
29、D6019. Determine the acid as described in Test MethodD3913.5. Results5.1 The basicity of the liquor shall be expressed according to the Schorlemmer system. In this system, the basicity is the percent of the total chromic oxide that is combined with hydroxyl and is calculated as follows:Basicity,%5A2
30、BA 3100 (1)where:A = the amount of thiosulfate, as mL of 0.1 N solution required to titrate the 25 mL aliquot as the specimen in Test MethodsD3898 or D6019,B = the amount of sodium hydroxide, as mL of 0.1 N solution required to titrate the 25 mL aliquot of the specimen in TestMethod D3913.6. Precisi
31、on and Bias6.1 Because basicity is in effect a ratio, the precision indexes are transmitted by the laws governing ratios. If the precision ofaccuracy of the chromic oxide determination or of the titratable acidity is expressed in the same relative units; for example, percentof value being determined
32、, the precision with which the basicity is known will be:PB5=PCR 21PA2 (2)where:PA = precision of acidity in basic chromium tanning liquors,PCR = precision of chromic oxide in basic chromium tanning liquors,PB = precision of basicity in basic chromium tanning liquors.6.2 For the reported reproducibi
33、lity figures for the chromic oxide from Test Method D3898 ( = 0.90 %) and for acidity fromTest Method D3913 (Procedure I, = 1.84 %), B is given as 2.05 %, and for the reported reproducibility figures for the chromicoxide from Test Method D6019 ( = 0.27 %) and for acidity from Test Method D3913 (Proc
34、edure 1, = 1.84 %), B is given as1.86 %. This number has the units of basicity. Similarly, repeatability has = 0.52 % basicity. Caution should be employed ininsisting on extremely close agreements between laboratories or replicates unless a background of high precision has beenestablished.37. Keywor
35、ds7.1 basicity; chrome tanning liquor; SchorlemmerASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent right
36、s, 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 re
37、vision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing yo
38、u 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, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be
39、 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 183
