ASTM D6019-20

Test Method for Determination of Chromic Oxide in Basic Chromium Tanning Liquors (Ammonium Persulfate Oxidation)

SIGNIFICANCE AND USE
4.1 The procedure described is for the quality control for manufacturing liquors and specifications for the purchase of such liquors.  
4.2 The chromium content of the liquors determines the amount to be used to obtain the desired degree of tannage, and hence may be a matter for specification in the purchase of leather.
SCOPE
1.1 This test method covers the determination of chromic oxide in chrome tanning liquors, either simple, with added aluminum or zirconium, or with the usual masking complexing agents.  
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 safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2020
• ICS: 59.140.10 - Processes and auxiliary materials
• ICS: 71.040.40 - Chemical analysis
• Technical Committee: D31 - Leather
• Drafting Committee: D31.06 - Chemical Analysis

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6019 − 20
Test Method for
Determination of Chromic Oxide in Basic Chromium
1
Tanning Liquors (Ammonium Persulfate Oxidation)
This standard is issued under the fixed designation D6019; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance and Use
1.1 This test method covers the determination of chromic 4.1 The procedure described is for the quality control for
oxide in chrome tanning liquors, either simple, with added manufacturing liquors and specifications for the purchase of
aluminum or zirconium, or with the usual masking complexing such liquors.
agents.
4.2 The chromium content of the liquors determines the
1.2 The values stated in SI units are to be regarded as amount to be used to obtain the desired degree of tannage, and
standard. No other units of measurement are included in this hence may be a matter for specification in the purchase of
standard. leather.
1.3 This standard does not purport to address all of the
5. Reagents and Materials
safety concerns, if any, associated with its use. It is the
5.1 Purity of Reagents—Reagent grade chemicals shall be
responsibility of the user of this standard to establish appro-
used in all tests. Unless otherwise indicated, it is intended that
priate safety, health, and environmental practices and deter-
all reagents shall conform to the specifications of the Commit-
mine the applicability of regulatory limitations prior to use.
tee onAnalytical Reagents ofTheAmerican Chemical Society,
1.4 This international standard was developed in accor-
2
where such specifications are available. Other grades may be
dance with internationally recognized principles on standard-
used, provided it is first ascertained that the reagent is of
ization established in the Decision on Principles for the
sufficiently high purity to permit its use without lessening the
Development of International Standards, Guides and Recom-
accuracy of the determination.
mendations issued by the World Trade Organization Technical
5.2 Purity of Water—Unless otherwise indicated, reference
Barriers to Trade (TBT) Committee.
to water shall be understood to mean distilled water, deionized
2. Summary of Test Method water or water of equal purity.
2.1 The solution is oxidized with ammonium persulfate 5.3 Ammonium Persulfate—20 % solution 100 g of persul-
until the chromium is completely converted to the chromate fate into 500 mL water.
ion. The solution is boiled to complete oxidation of organic 5.3.1 Alternatively, ammonium persulfate may be added in
materialsandtodestroyexcessammoniumpersulfate;itisthen 6.6 as solid form using plastic scoopula.
cooled and acidified. Potassium iodide is added, and the
5.4 Starch Indicator,2%—Make a paste of2gof soluble
liberated iodine is titrated with standardized sodium thiosul-
starch in about 10 mL of water, add 90 mL water, and boil for
fate.
1 min with stirring. Cool. Refrigerate after use. The solution is
subject to decomposition and should be renewed if a deep blue
3. Terminology
color is not obtained on addition of one drop of indicator to a
3.1 Definitions: solution of 1 drop tincture of iodine in 100 mL of water.
3.1.1 recycled chrome (reacidified chrome), n—the mixture
5.5 Sodium Thiosulfate Solution, 0.1 N—Dissolve 24.85 g
obtained when spent chrome liquor is captured, filtered,
of Na S O ·5H O in water, add1gNa CO , and dilute to 1 L.
2 2 3 2 2 3
precipitated with alkali and the precipitate is reacidified with
5.5.1 Standardization—Dry potassium dichromate
sulfuric acid.
(K Cr O ) in an oven at 130°C for 2 h and cool in a desiccator.
2 2 7
2
Reagent Chemicals, American Chemical Society Specifications , American
1
This test method is under the jurisdiction ofASTM Committee D31 on Leather Chemical Society, Washington, DC. For suggestions on the testing of reagents not
and is the direct responsibility of Subcommittee D31.06 on Chemical Analysis. listed by the American Chemical Society, see Analar Standards for Laboratory
Current edition approved April 1, 2020. Published May 2020. Originally Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
approved in 1996. Last previous edition approved in 2015 as D6019 – 15. DOI: and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
10.1520/D6019-20. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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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 previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: D6019 − 15 D6019 − 20
Test Method for
Determination of Chromic Oxide in Basic Chromium
1
Tanning Liquors (Ammonium Persulfate Oxidation)
This standard is issued under the fixed designation D6019; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of chromic oxide in chrome tanning liquors, either simple, with added aluminum
or zirconium, or with the usual masking complexing agents.
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 safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Summary of Test Method
2.1 The solution is oxidized with ammonium persulfate until the chromium is completely converted to the chromate ion. The
solution is boiled to complete oxidation of organic materials and to destroy excess ammonium persulfate; it is then cooled and
acidified. Potassium iodide is added, and the liberated iodine is titrated with standardized sodium thiosulfate.
3. Terminology
3.1 Definitions:
3.1.1 recycled chrome (reacidified chrome), n—the mixture obtained when spent chrome liquor is captured, filtered, precipitated
with alkali and the precipitate is reacidified with sulfuric acid.
4. Significance and Use
4.1 The procedure described is for the quality control for manufacturing liquors and specifications for the purchase of such
liquors.
4.2 The chromium content of the liquors determines the amount to be used to obtain the desired degree of tannage, and hence
may be a matter for specification in the purchase of leather.
5. Reagents and Materials
5.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of The American Chemical Society, where
2
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
5.2 Purity of Water—Unless otherwise indicated, reference to water shall be understood to mean distilled water, deionized water
or water of equal purity.
5.3 Ammonium Persulfate—20 % solution 100 g of persulfate into 500 mL water.
1
This 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 Dec. 1, 2015April 1, 2020. Published January 2016May 2020. Originally approved in 1996. Last previous edition approved in 20102015 as
D6019 – 10.D6019 – 15. DOI: 10.1520/D6019-15.10.1520/D6019-20.
2
Reagent Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D6019 − 20
5.3.1 Alternatively, ammonium persulfate may be added in 5.56.6 as solid form using plastic scoopula.
5.4 Starch Indicator, 2 %—Make a paste of 2 g of soluble starch in about 10 mL of water, add 90 mL water, and boil for 1 min
with stirring. Cool. Refrigerate after use. The solution is subject to decomposition and should be renewed if a deep blue color is
not obtained on addition of one drop of indicator to a solution of 1 drop tincture of iodine in 100 mL o
...