ASTM D6714-01(2015)

Standard Test Method for Chromic Oxide in Ashed Wet Blue (Perchloric Acid Oxidation)

SIGNIFICANCE AND USE
5.1 The procedure described is specific for chromium in wet blue. Vanadium is the only common interfering element and this is rarely present in quantity. The precision and accuracy of the methods are usually at least as good as the sampling of the wet blue itself, and the accuracy of previously performed test methods.  
5.2 The chromium content of wet blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of wet blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the determination of chromic oxide in wet blue that has been partly or completely tanned with chromium compounds. In general the samples will contain chromium content between 1 and 5 %, calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).  
1.2 This test method is specific in that it applies to a sample or samples that are the resultant ash following the execution of Test Method D6716.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 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. Specific hazards are given in Section 8.

General Information

• Status: Historical
• Publication Date: 30-Nov-2015
• ICS: 59.140.30 - Leather and furs
• Technical Committee: D31 - Leather
• Drafting Committee: D31.02 - Wet Blue

Relations

• Replaces: ASTM D6714-01(2010)e1 - Standard Test Method for Chromic Oxide in Ashed Wet Blue (Perchloric Acid Oxidation)
• Effective Date: 01-Dec-2015
• Referred By: ASTM D6716-08(2020) - Standard Test Method for Total Ash in Wet Blue or Wet White
• Effective Date: 01-Dec-2015

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6714 − 01 (Reapproved2015)
Standard Test Method for
Chromic Oxide in Ashed Wet Blue (Perchloric Acid
Oxidation)
This standard is issued under the fixed designation D6714; 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 3. Terminology
1.1 This test method covers the determination of chromic
3.1 Definitions—The terms and definitions employed within
oxide in wet blue that has been partly or completely tanned this test method are commonly used in normal laboratory
with chromium compounds. In general the samples will con-
practice and require no special comment.
tain chromium content between 1 and 5 %, calculated as
chromic oxide expressed upon a dry basis otherwise referred to
4. Summary of Test Method
as moisture-free basis (mfb).
4.1 The perchloric acid method may be applied to the ash
1.2 This test method is specific in that it applies to a sample
obtained in Test Method D6716. The resultant ash is dissolved
or samples that are the resultant ash following the execution of
into acidic solution in a blend of nitric acid and a prepared
Test Method D6716.
oxidation mixture consisting of sulfuric and perchloric acids.
Once completed, oxidation of all trivalent to hexavalent
1.3 The values stated in SI units are to be regarded as
chromiumisexecutedbycontrolledheating.Upondilution,the
standard. No other units of measurement are included in this
chromium is indirectly (back) titrated volumetrically with
standard.
standardizedthiosulfateusingreleasediodineasthetitrate.The
1.4 This standard does not purport to address all of the
perchloric acid method requires less manipulation than proce-
safety concerns, if any, associated with its use. It is the
dures based on fusion of the ash. However care must be taken
responsibility of the user of this standard to establish appro-
because of potential hazards in the use of perchloric acid. The
priate safety and health practices and determine the applica-
perchloric acid method also tends to give low results.
bilityofregulatorylimitationspriortouse.Specifichazardsare
given in Section 8.
5. Significance and Use
5.1 The procedure described is specific for chromium in wet
2. Referenced Documents
blue. Vanadium is the only common interfering element and
2.1 ASTM Standards:
this is rarely present in quantity. The precision and accuracy of
D6658 Test Method for Volatile Matter (Moisture) of Wet
the methods are usually at least as good as the sampling of the
Blue by Oven Drying
wet blue itself, and the accuracy of previously performed test
D6659 Practice for Sampling and Preparation of Wet Blue
methods.
for Physical and Chemical Tests
5.2 The chromium content of wet blue is related to the
D6716 Test Method for TotalAsh in Wet Blue or Wet White
degree of tannage obtained, and hence may be a matter for
E180 Practice for Determining the Precision of ASTM
specification in the purchase of wet blue. The procedure
Methods for Analysis and Testing of Industrial and Spe-
described provides adequate accuracy for this purpose.
cialty Chemicals (Withdrawn 2009)
6. Apparatus
6.1 Analytical Balance, accurate and calibrated to 0.001 g.
This test method is under the jurisdiction ofASTM Committee D31 on Leather
and is the direct responsibility of Subcommittee D31.02 on Wet Blue.
6.2 Erlenmeyer Flasks, 250 mL capacity or equivalent.
Current edition approved Dec. 1, 2015. Published December 2015. Originally
ɛ
approved in 2001. Last previous edition approved in 2010 as D6714 - 01(2010) .
6.3 Burette, 50 mL capacity of suitable calibration grade,
DOI: 10.1520/D6714-01R15.
2 minimum calibration of 0.1 mL.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
6.4 Glass Anti-bumping Beads, or equivalent.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
6.5 Measuring Cylinders, 50 mL capacity or equivalent.
The last approved version of this historical standard is referenced on
www.astm.org. 6.6 Small Glass Filter Funnel.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6714 − 01 (2015)
6.7 Dessicator, of suitable size and design and charged with 7.15 Sodium Thiosulfate—(Na S O ·5H O). Used to pre-
2 2 3 2
fresh dessicant. pare thiosulfate solution.
6.8 Weighing Vessels, of suitable size and design.
7.16 Sodium Thiosulfate Standard Solution—(Na S O ),
2 2 3
0.1N (60.0002). Dissolve 24.85 g of sodium thiosulfate
6.9 Drying Oven, with accurate variable temperature con-
(Na S O ·5H O) in previously boiled water, add 1.00 g of
trols. 2 2 3 2
sodium carbonate (Na CO ) and dilute to 1000 mL.
2 3
6.10 Hot Plate, with accurate variable temperature controls.
7.16.1 Standardization—Dry potassium dichromate
(K Cr O ) in an oven at 130°C for 2 h and cool in a dessicator.
2 2 7
7. Reagents
Once cool, weigh about 0.2 g (60.0001 g) of this dry
7.1 Purity of Reagents—Analytical Reagent (AR) grade
potassium dichromate into a clean 250 mL, glass-stoppered
chemicals shall be used in all tests. Unless otherwise indicated,
Erlenmeyer flask. Dissolve in 50 mL of water; add 4 mL of
it is intended that all reagents shall conform to specifications of
hydrochloricacid(HCl,1:1)and20mLofKIsolution.Stopper
theCommitteeonAnalyticalReagentsoftheAmericanChemi-
the flask, and allow to stand 5 min in the dark. Titrate with the
cal Society, where such specifications are available. Other
thiosulfate solution to be standardized. When the color of the
grades may be used, provided it is first ascertained that the
solutionhasfadedtoabrownish-green,add2mLof2 %starch
reagent is of sufficiently high purity to permit its use without
solutionandcontinuetitratinguntilthedeepbluecolorchanges
lessening the accuracy of the determination.
toacleargreen.Recordthetitration.Calculatethenormalityof
the thiosulfate solution as follows:
7.2 Purity of Water—Unless otherwise indicated, reference
to water shall be understood to mean distilled water or water of
Normality 5 A÷ 0.04903 3B
~ !
equal purity.
where:
7.3 Commercial Reagents—The use of commercially avail-
A =K Cr O used, g, and
2 2 7
able pre-standardized analytical reagents and solutions is
B = amount required for titration, mL.
appropriate, providing those reagents and solutions have been
prepared in accordance with and conforming to the previously
7.16.2 Shelf Life—The thiosulfate solution is relatively
mentioned specifications (see 7.1). stable. However, it should be restandardized at least once a
month.
7.4 Nitric Acid—(HNO ), 70 % w/w.
7.17 Alternatively, a commercially available pre-
7.5 Perchloric Acid—(HClO ), 60 to 62 % w/w. 70 or 72 %
standardized sodium thiosulfate analytical solution may be
w/w perchloric acid may be substituted, however, storage is
substituted.
somewhat more hazardous.
7.6 Sulfuric Acid—(H SO ), 96 to 98 % w/w.
2 4
8. Hazards
7.7 Potassium Iodide—(KI), 99 to 100 % purity.
8.1 Chemicals used can be harmful, or explosive, or both.
7.8 PotassiumIodideSolution—(KI)10 %w/w.Dissolve10
8.2 The improper use of perchloric acid can lead to violent
g(60.1 g) of potassium iodide into 100 mL of water.
and serious explosions. In general, these can be traced to
7.9 Starch Indicator Solution—2 % or equivalent, prepared
situations where concentrated perchloric acid has come in
according to accepted procedures available in analytical hand-
contact with organic or easily oxidized materials.
books.
8.3 The exact procedures given must be followed and the
7.10 Oxidizing Mixture—Mix 1666 mL of concentrated
di
...

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.
´1
Designation: D6714 − 01 (Reapproved 2010) D6714 − 01 (Reapproved 2015)
Standard Test Method for
Chromic Oxide in Ashed Wet Blue (Perchloric Acid
Oxidation)
This standard is issued under the fixed designation D6714; 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.
ε NOTE—The SI statement was added and the Subcommittee name in footnote 1 was corrected editorially in November
2010.
1. Scope
1.1 This test method covers the determination of chromic oxide in wet blue that has been partly or completely tanned with
chromium compounds. In general the samples will contain chromium content between 1 and 5 %, calculated as chromic oxide
expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).
1.2 This test method is specific in that it applies to a sample or samples that are the resultant ash following the execution of
Test Method D6716.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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. Specific hazards are given in Section 8.
2. Referenced Documents
2.1 ASTM Standards:
D6658 Test Method for Volatile Matter (Moisture) of Wet Blue by Oven Drying
D6659 Practice for Sampling and Preparation of Wet Blue for Physical and Chemical Tests
D6716 Test Method for Total Ash in Wet Blue or Wet White
E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
(Withdrawn 2009)
3. Terminology
3.1 Definitions—The terms and definitions employed within this test method are commonly used in normal laboratory practice
and require no special comment.
4. Summary of Test Method
4.1 The perchloric acid method may be applied to the ash obtained in Test Method D6716. The resultant ash is dissolved into
acidic solution in a blend of nitric acid and a prepared oxidation mixture consisting of sulfuric and perchloric acids. Once
completed, oxidation of all trivalent to hexavalent chromium is executed by controlled heating. Upon dilution, the chromium is
indirectly (back) titrated volumetrically with standardized thiosulfate using released iodine as the titrate. The perchloric acid
method requires less manipulation than procedures based on fusion of the ash. However care must be taken because of potential
hazards in the use of perchloric acid. The perchloric acid method also tends to give low results.
5. Significance and Use
5.1 The procedure described is specific for chromium in wet blue. Vanadium is the only common interfering element and this
is rarely present in quantity. The precision and accuracy of the methods are usually at least as good as the sampling of the wet blue
itself, and the accuracy of previously performed test methods.
This test method is under the jurisdiction of ASTM Committee D31 on Leather and is the direct responsibility of Subcommittee D31.02 on Wet Blue.
Current edition approved Oct. 1, 2010Dec. 1, 2015. Published November 2010December 2015. Originally approved in 2001. Last previous edition approved in 20062010
ɛ
as D6714 - 01 (2006).(2010) . DOI: 10.1520/D6714-01R10E01.10.1520/D6714-01R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6714 − 01 (2015)
5.2 The chromium content of wet blue is related to the degree of tannage obtained, and hence may be a matter for specification
in the purchase of wet blue. The procedure described provides adequate accuracy for this purpose.
6. Apparatus
6.1 Analytical Balance, accurate and calibrated to 0.001 g.
6.2 Erlenmeyer Flasks, 250 mL capacity or equivalent.
6.3 Burette, 50 mL capacity of suitable calibration grade, minimum calibration of 0.1 mL.
6.4 Glass Anti-bumping Beads, or equivalent.
6.5 Measuring Cylinders, 50 mL capacity or equivalent.
6.6 Small Glass Filter Funnel.
6.7 Dessicator, of suitable size and design and charged with fresh dessicant.
6.8 Weighing Vessels, of suitable size and design.
6.9 Drying Oven, with accurate variable temperature controls.
6.10 Hot Plate, with accurate variable temperature controls.
7. Reagents
7.1 Purity of Reagents—Analytical Reagent (AR) grade chemicals shall be used in all tests. Unless otherwise indicated, it is
intended that all reagents shall conform to specifications of the Committee on Analytical Reagents of the American Chemical
Society, where 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.
7.2 Purity of Water—Unless otherwise indicated, reference to water shall be understood to mean distilled water or water of equal
purity.
7.3 Commercial Reagents—The use of commercially available pre-standardized analytical reagents and solutions is appropriate,
providing those reagents and solutions have been prepared in accordance with and conforming to the previously mentioned
specifications (see 7.1).
7.4 Nitric Acid—(HNO ), 70 % w/w.
7.5 Perchloric Acid—(HClO ), 60 to 62 % w/w. 70 or 72 % w/w perchloric acid may be substituted, however, storage is
somewhat more hazardous.
7.6 Sulfuric Acid—(H SO ), 96 to 98 % w/w.
2 4
7.7 Potassium Iodide—(KI), 99 to 100 % purity.
7.8 Potassium Iodide Solution—(KI) 10 % w/w. Dissolve 10 g (60.1 g) of potassium iodide into 100 mL of water.
7.9 Starch Indicator Solution—2 % or equivalent, prepared according to accepted procedures available in analytical handbooks.
7.10 Oxidizing Mixture—Mix 1666 mL of concentrated sulfuric acid into an appropriate glass container that contains 2500 mL
of perchloric acid, using extreme caution while adding. Cool the mixture to room temperature before use.
7.11 Phosphoric Acid—(H PO ), 40 % v/v. Dilute 45 mL of 85 % phosphoric acid with water to 100 mL.
3 4
7.12 Hydrochloric Acid—(HCl), 1:1 dilution of 37 % HCl w/w. Used in standardization of thiosulfate solution.
7.13 Potassium Dichromate—(K Cr O ). Used in standardization of thiosulfate solution.
2 2 7
7.14 Sodium Carbonate—(Na CO ). Used in preparation of thiosulfate solution.
2 3
7.15 Sodium Thiosulfate—(Na S O · 5H O). Used to prepare thiosulfate solution.
2 2 3 2
7.16 Sodium Thiosulfate Standard Solution—(Na S O ), 0.1N (60.0002). Dissolve 24.85 g of sodium thiosulfate
2 2 3
(Na S O · 5H O) in previously boiled water, add 1.00 g of sodium carbonate (Na CO ) and dilute to 1000 mL.
2 2 3 2 2 3
7.16.1 Standardization—Dry potassium dichromate (K Cr O ) in an oven at 130°C for 2 h and cool in a dessicator. Once cool,
2 2 7
weigh about 0.2 g (60.0001 g) of this dry potassium dichromate into a clean 250 mL, glass-stoppered Erlenmeyer flask. Dissolve
in 50 mL of water; add 4 mL of hydrochloric acid (HCl, 1:1) and 20 mL of KI solution. Stopper the flask, and allow to stand 5
min in the dark. Titrate with the thiosulfate solution to be standardized. When the color of the solution has faded to a
Reagent Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, D.C. F
...