ASTM D6019-15
(Test Method)Test Method for Determination of Chromic Oxide in Basic Chromium Tanning Liquors (Ammonium Persulfate Oxidation)
Test Method for Determination of Chromic Oxide in Basic Chromium Tanning Liquors (Ammonium Persulfate Oxidation)
SIGNIFICANCE AND USE
3.1 The procedure described is for the quality control for manufacturing liquors and specifications for the purchase of such liquors.
3.2 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D6019 − 15
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 tee onAnalytical Reagents ofTheAmerican Chemical Society,
2
where such specifications are available. Other grades may be
1.1 This test method covers the determination of chromic
used, provided it is first ascertained that the reagent is of
oxide in chrome tanning liquors, either simple, with added
sufficiently high purity to permit its use without lessening the
aluminum or zirconium, or with the usual masking complexing
accuracy of the determination.
agents.
4.2 Purity of Water—Unless otherwise indicated, reference
1.2 The values stated in SI units are to be regarded as
to water shall be understood to mean distilled water, deionized
standard. No other units of measurement are included in this
water or water of equal purity.
standard.
1.3 This standard does not purport to address all of the 4.3 Ammonium Persulfate—20 % solution 100 g of persul-
safety concerns, if any, associated with its use. It is the
fate into 500 mL water.
responsibility of the user of this standard to establish appro-
4.3.1 Alternatively, ammonium persulfate may be added in
priate safety and health practices and determine the applica-
5.5 as solid form using plastic scoopula.
bility of regulatory limitations prior to use.
4.4 Starch Indicator,2%—Make a paste of2gof soluble
2. Summary of Test Method 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
2.1 The solution is oxidized with ammonium persulfate
subject to decomposition and should be renewed if a deep blue
until the chromium is completely converted to the chromate
color is not obtained on addition of one drop of indicator to a
ion. The solution is boiled to complete oxidation of organic
solution of 1 drop tincture of iodine in 100 mL of water.
materialsandtodestroyexcessammoniumpersulfate;itisthen
cooled and acidified. Potassium iodide is added, and the
4.5 Sodium Thiosulfate Solution, 0.1 N—Dissolve 24.85 g
liberated iodine is titrated with standardized sodium thiosul-
of Na S O ·5H O in water, add1gNa CO , and dilute to 1 L.
2 2 3 2 2 3
fate.
4.5.1 Standardization—Dry potassium dichromate
(K Cr O ) in an oven at 130°C for 2 h and cool in a desiccator.
2 2 7
3. Significance and Use
Weigh into a glass stoppered Erlenmeyer flask (500 mL) about
3.1 The procedure described is for the quality control for
0.2 g of potassium dichromate to an accuracy of 0.1 mg.
manufacturing liquors and specifications for the purchase of
Dissolvein250mLwater,add15mL1:4hydrochloricacid,20
such liquors.
mL of 10 % potassium iodide solution, stopper the flask, and
allow to stand 5 min in the dark. Titrate with the sodium
3.2 The chromium content of the liquors determines the
thiosulfate to be standardized. When the color of the solution
amount to be used to obtain the desired degree of tannage, and
has faded to a brownish-green, add 2 mL of 2 % starch
hence may be a matter for specification in the purchase of
solution, and continue titrating until the deep blue color
leather.
changes to a clear green. Record the titration.
4. Reagents and Materials
weight potassium dichromate
normality of sodium thiosulfate 5 (1)
4.1 Purity of Reagents—Reagent grade chemicals shall be
0.04903 3mL titration
used in all tests. Unless otherwise indicated, it is intended that
all reagents shall conform to the specifications of the Commit-
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 Dec. 1, 2015. Published January 2016. Originally Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
approved in 1996. Last previous edition approved in 2010 as D6019 – 10. DOI: and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
10.1520/D6019-15. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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D6019 − 15
NOTE 2—This will produce a purple color.
The thiosulfate solution is quite stabl
...
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 − 10 D6019 − 15
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 and health practices and determine the applicability of regulatory
limitations prior to use.
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. Significance and Use
3.1 The procedure described is for the quality control for manufacturing liquors and specifications for the purchase of such
liquors.
3.2 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.
4. Reagents and Materials
4.1 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.
4.2 Purity of Water—Unless otherwise indicated, reference to water shall be understood to mean distilled water, deionized water
or water of equal purity.
4.3 Ammonium Persulfate—20 % solution 100 gmg of persulfate into 500 mL water.
4.3.1 Alternatively, ammonium persulfate may be added in 5.5 as solid form using plastic scoopula.
4.4 Starch Indicator, 1 %2 %—Make a paste of 12 g of soluble starch in about 10 mL of water, add 90 mL water, and boil for
1 min with stirring. Cool and add one drop of chloroform. 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 of water.
4.5 Sodium Thiosulfate Solution, 0.1 N—Dissolve 24.85 g of Na S O ·5H O in water, add 1 g Na CO , and dilute to 1 L.
2 2 3 2 2 3
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 Oct. 1, 2010Dec. 1, 2015. Published October 2010January 2016. Originally approved in 1996. Last previous edition approved in 20062010 as
D6019 - 96D6019 – 10.(2006). DOI: 10.1520/D6019-10.10.1520/D6019-15.
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
---------------------- Page: 1 ----------------------
D6019 − 15
4.5.1 Standardization—Dry potassium dichromate (K Cr O ) in an oven at 130°C for 2 h and cool in a desiccator. Weigh into
2 2 7
a glass stoppered Erlenmeyer flask (500 mL) about 0.2 g of potassium dichromate to an accuracy of 0.1 mg. Dissolve in 250 mL
water, add 15 mL 1:4 hydrochloric acid, 20 mL of 10 % potassium iodide solution, stopper the flask, and allow to stand 5 min in
the dark.
...
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