ASTM D6408-99(2020)
(Test Method)Standard Test Method for Analysis of Tannery Liquors
Standard Test Method for Analysis of Tannery Liquors
SIGNIFICANCE AND USE
5.1 This test method is used to determine the chemical properties of tannery liquors which are relevant for the vegetable tanning process and influence the astringency of vegetable tanning liquors. The astringency of liquors is dependent upon the solids and tannin content and the acidity. This method provides a standard procedure for determining these properties for any sample of vegetable tanning liquor.
5.2 The specimens are aliquots from the analytical solution prepared from the sample of tannery liquor collected for this purpose.
5.3 The total solids, soluble solids, and non-tannins content are determined and then the tannin content of the liquor sample is calculated. Because the amount of tannin per liter of analytical solution is less than that required for Test Method D6401, a table specifying the quantity of prepared hide powder to be used for solutions with lower tannin concentrations is included in this test method.
5.4 The total acidity of the liquor sample is determined by one of two titrametric procedures described in Test Method D6410.
5.5 The results of this test method are dependent on a great many variables but particularly upon: the temperature conditions under which the solutions were prepared and stored and the temperature at which the current analysis is performed; the uniformity and consistency of the Kaolin paste layer deposited onto the filter paper; the rate of solution run-out from the pipette; conditions related to the properties of the hide powder used to react with the tannin content of the solution; etc. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method covers the analysis of tannery liquors made up from vegetable tanning materials.
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
Relations
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: D6408 − 99 (Reapproved 2020)
Standard Test Method for
Analysis of Tannery Liquors
This standard is issued under the fixed designation D6408; 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 2.2 ALCA Methods:
A25 Analysis of Tannery Liquors
1.1 This test method covers the analysis of tannery liquors
made up from vegetable tanning materials.
3. Terminology
1.2 The values stated in SI units are to be regarded as
3.1 Definitions:
standard. No other units of measurement are included in this
3.1.1 tannery liquor—water solutions containing vegetable
standard.
tannin that are made up and used in a vegetable tannery.
1.3 This standard does not purport to address all of the 3.1.2 tannin—an astringent substance found in the various
parts of plants such as bark, wood, leaves, nuts, fruits, roots,
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- etc. Also, quantitatively, tannins are operationally defined as
priate safety, health, and environmental practices and deter- the non-volatile materials present in tannin extracts and raw or
spent materials that are dissolved or suspended in water, are
mine the applicability of regulatory limitations prior to use.
part of the soluble solids determined by Test Method D6402,
1.4 This international standard was developed in accor-
and do react with or bind to hide powder when mixed as in this
dance with internationally recognized principles on standard-
test method.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 3.1.3 vegetable tannins—mixtures of substances (natural
mendations issued by the World Trade Organization Technical
products) obtained from plant tissues by water extraction
Barriers to Trade (TBT) Committee. which have the chemical and physical properties necessary to
convert animal hides and skins into leather.
2. Referenced Documents
4. Summary of Test Method
2.1 ASTM Standards:
4.1 An analytical solution is prepared from the sample of
D4903 Test Method for Total Solids and Water in Vegetable
tannery liquor (Practice D6404). Specimen aliquots from this
Tanning Material Extracts
analytical solution are then analyzed for total solids (Test
D4904 Practice for Cooling of Analytical Solutions
Method D4903), soluble solids and insolubles (Test Method
D6401 Test Method for Determining Non-Tannins and Tan-
D6402), non-tannins and tannin (Test Method D6401), and
nin in Extracts of Vegetable Tanning Materials
total acidity (Test Method D6410).
D6402 Test Method for Determining Soluble Solids and
Insolubles in Extracts of Vegetable Tanning Materials
5. Significance and Use
D6404 Practice for Sampling Vegetable Materials Contain-
5.1 This test method is used to determine the chemical
ing Tannin
properties of tannery liquors which are relevant for the
D6410 Test Method for Determining Acidity of Vegetable
vegetable tanning process and influence the astringency of
Tanning Liquors
vegetable tanning liquors. The astringency of liquors is depen-
dent upon the solids and tannin content and the acidity. This
method provides a standard procedure for determining these
This test method is under the jurisdiction ofASTM Committee D31 on Leather
properties for any sample of vegetable tanning liquor.
and is the direct responsibility of Subcommittee D31.01 . This test method has been
adapted from and is a replacement for Method A25 of the Official Methods of the
5.2 The specimens are aliquots from the analytical solution
American Leather Chemists Association.
prepared from the sample of tannery liquor collected for this
Current edition approved Dec. 1, 2020. Published December 2020. Originally
purpose.
approved in 1999. Last previous edition approved in 2014 as D6408 – 99 (2014).
DOI: 10.1520/D6408-99R20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Official Methods of the American Leather Chemists Association. Available
Standards volume information, refer to the standard’s Document Summary page on from the American Leather Chemists Association, University of Cincinnati, P.O.
the ASTM website. Box 210014, Cincinnati, OH 45221-0014.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6408 − 99 (2020)
5.3 The total solids, soluble solids, and non-tannins content 6.3.2 pH Meter, with glass/calomel electrodes.
aredeterminedandthenthetannincontentoftheliquorsample 6.3.3 Alkaline Titrant, 0.1 N sodium hydroxide solution.
is calculated. Because the amount of tannin per liter of
analytical solution is less than that required for Test Method 7. Test Specimen
D6401,atablespecifyingthequantityofpreparedhidepowder
7.1 The specimens for the tannin determination shall consist
to be used for solutions with lower tannin concentrations is
of 100 mLaliquots of the analytical solution prepared from the
included in this test method.
tannery liquor sample or the filtrates collected for particular
5.4 The total acidity of the liquor sample is determined by methods.
one of two titrametric procedures described in Test Method
7.2 Thespecimenfordeterminationofacidityshallbeeither
D6410.
a 25 mL aliquot (for titration - Method 1) or a 6.0 mL aliquot
5.5 The results of this test method are dependent on a great
(for titration - Method 2) from the analytical solution prepared
many variables but particularly upon: the temperature condi- from the tannery liquor sample.
tions under which the solutions were prepared and stored and
the temperature at which the current analysis is performed; the
8. Procedure
uniformity and consistency of the Kaolin paste layer deposited
8.1 Preparation of the Analytical Solution:
onto the filter paper; the rate of solution run-out from the
8.1.1 Collect the tannery liquor sample as described in
pipette; conditions related to the pr
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