Standard Test Method for Analysis of Tannery Liquors

SIGNIFICANCE AND USE
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.
The specimens are aliquots from the analytical solution prepared from the sample of tannery liquor collected for this purpose.
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 D 6401, a table specifying the quantity of prepared hide powder to be used for solutions with lower tannin concentrations is included in this test method.
The total acidity of the liquor sample is determined by one of two titrametric procedures described in Test Method D 6410.
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 and health practices and determine the applicability of regulatory limitations prior to use.

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Historical
Publication Date
31-Mar-2009
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Drafting Committee
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ASTM D6408-99(2009) - Standard Test Method for Analysis of Tannery Liquors
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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: D6408 − 99 (Reapproved2009)
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 3.1.1 tannery liquor—water solutions containing vegetable
tannin that are made up and used in a vegetable tannery.
1.1 This test method covers the analysis of tannery liquors
made up from vegetable tanning materials.
3.1.2 tannin—an astringent substance found in the various
parts of plants such as bark, wood, leaves, nuts, fruits, roots,
1.2 The values stated in SI units are to be regarded as
etc. Also, quantitatively, tannins are operationally defined as
standard. No other units of measurement are included in this
the non-volatile materials present in tannin extracts and raw or
standard.
spent materials that are dissolved or suspended in water, are
1.3 This standard does not purport to address all of the
part of the soluble solids determined by Test Method D6402,
safety concerns, if any, associated with its use. It is the
and do react with or bind to hide powder when mixed as in this
responsibility of the user of this standard to establish appro-
test method.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 3.1.3 vegetable tannins—mixtures of substances (natural
products) obtained from plant tissues by water extraction
2. Referenced Documents
which have the chemical and physical properties necessary to
convert animal hides and skins into leather.
2.1 ASTM Standards:
D4903 Test Method for Total Solids and Water in Vegetable
4. Summary of Test Method
Tanning Material Extracts
D4904 Practice for Cooling of Analytical Solutions
4.1 An analytical solution is prepared from the sample of
D6401 Test Method for Determining Non-Tannins and Tan-
tannery liquor (Practice D6404). Specimen aliquots from this
nin in Extracts of Vegetable Tanning Materials
analytical solution are then analyzed for total solids (Test
D6402 Test Method for Determining Soluble Solids and
Method D4903), soluble solids and insolubles (Test Method
Insolubles in Extracts of Vegetable Tanning Materials
D6402), non-tannins and tannin (Test Method D6401), and
D6404 Practice for Sampling Vegetable Materials Contain-
total acidity (Test Method D6410).
ing Tannin
D6410 Test Method for Determining Acidity of Vegetable
5. Significance and Use
Tanning Liquors
5.1 This test method is used to determine the chemical
2.2 ALCA Methods:
properties of tannery liquors which are relevant for the
A25 Analysis of Tannery Liquors
vegetable tanning process and influence the astringency of
3. Terminology
vegetable tanning liquors. The astringency of liquors is depen-
dent upon the solids and tannin content and the acidity. This
3.1 Definitions:
method provides a standard procedure for determining these
properties for any sample of vegetable tanning liquor.
This test method is under the jurisdiction ofASTM Committee D31 on Leather
5.2 The specimens are aliquots from the analytical solution
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
prepared from the sample of tannery liquor collected for this
American Leather Chemists Association.
purpose.
Current edition approved April 1, 2009. Published July 2009. Originally
approved in 1999. Last previous edition approved in 2004 as D6408 – 99 (2004).
5.3 The total solids, soluble solids, and non-tannins content
DOI: 10.1520/D6408-99R09.
aredeterminedandthenthetannincontentoftheliquorsample
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
is calculated. Because the amount of tannin per liter of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
analytical solution is less than that required for Test Method
the ASTM website.
D6401,atablespecifyingthequantityofpreparedhidepowder
Official Methods of the American Leather Chemists Association. Available
to be used for solutions with lower tannin concentrations is
from the American Leather Chemists Association, University of Cincinnati, P.O.
Box 210014, Cincinnati, OH 45221-0014. included in this test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6408 − 99 (2009)
5.4 The total acidity of the liquor sample is determined by 7.2 Thespecimenfordeterminationofacidityshallbeeither
one of two titrametric procedures described in Test Method a 25 mL aliquot (for titration - Method 1) or a 6.0 mL aliquot
D6410. (for titration - Method 2) from the analytical solution prepared
from the tannery liquor sample.
5.5 The results of this test method are dependent on a great
many variables but particularly upon: the temperature condi-
8. Procedure
tions under which the solutions were prepared and stored and
8.1 Preparation of the Analytical Solution:
the temperature at which the current analysis is performed; the
8.1.1 Collect the tannery liquor sample as described in
uniformity and consistency of the Kaolin paste layer deposited
Practice D6404 (11.10).
onto the filter paper; the rate of solution run-out from the
8.1.2 Prepare the analytical solution for this analysis by
pipette; conditions related to the properties of the hide powder
diluting a specimen aliquot from the tannery liquor sample to
used to react with the tannin content of the solution; etc. It is,
the mark ina1L volumetric flask with distilled water. The
therefore, essential that the method be followed exactly in
aliquot specimen shall be of such size that, after dilution the
order to obtain reproducible results both among specimens
analyticalsolutionshallcontainasnearlyaspossible7.0gto
...

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