ASTM D3897-91(1996)

Standard Practice for Calculation of Basicity of Chrome Tanning Liquors

SCOPE
1.1 This practice is intended to show how the results of the chromium analysis (Test Method D 3898) and the acidity determination (Test Method D 3913) can be combined to permit calculation of the basicity of a chrome tanning liquor.
1.2 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.

General Information

• Status: Historical
• Publication Date: 14-May-1991
• Technical Committee: D31 - Leather
• Drafting Committee: D31.06 - Chemical Analysis

Relations

• Replaced By: ASTM D3897-91(2001) - Standard Practice for Calculation of Basicity of Chrome Tanning Liquors
• Effective Date: 15-May-1991

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 3897 – 91 (Reapproved 1996)
Standard Practice for
Calculation of Basicity of Chrome Tanning Liquors
This standard is issued under the fixed designation D 3897; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope hydroxyl and is calculated as follows:
1.1 This practice is intended to show how the results of the A 2 B
Basicity, % 5 3 100 (1)
A
chromium analysis (Test Method D 3898) and the acidity
determination (Test Method D 3913) can be combined to
where:
permit calculation of the basicity of a chrome tanning liquor.
A 5 the amount of thiosulfate, as mL of 0.1 N solution
1.2 This standard does not purport to address all of the
required to titrate the 25 mL aliquot as the specimen in
safety concerns, if any, associated with its use. It is the
Test Method D 3898,
responsibility of the user of this standard to establish appro-
B 5 the amount of sodium hydroxide, as mL of 0.1 N
priate safety and health practices and determine the applica-
solution required to titrate the 25 mL aliquot of the
bility of regulatory limitations prior to use.
specimen in Test Method D 3913.
2. Referenced Documents
6. Precision and Bias
2.1 ASTM Standards:
6.1 Because basicity is in effect a ratio, the precision
D 3898 Test Method for Chromic Oxide in Basic Chro-
indexes are transmitted by the laws governing ratios. If the
mium Tanning Liquors
precision of accuracy of the chromic oxide determination or of
D 3913 Test Method for Acidity in Basic Chromium Tan-
the titratable acidity is expressed in the same relative units; for
ning Liquors
example, percent of value being determined, the precision with
E 180 Practice for Determining the Precision of ASTM
which the basicity is known will be:
Methods for the Analysis and Testing of Industrial Chemi-
cals
2 2
P 5 P 1 P (2)
=
B C A
R
3. Significance and Use
where:
3.1 Basicity is a ratio. In any chromic salt solution, the
P 5 precision of acidity in basic chromium tanning
A
electrovalence of the chromium (+3) is satisfied by the hy-
liquors,
droxyl ions and by acid ions. The extent to which this
P 5 precision of chromic oxide in basic chromium
C
R
electravalence is satisfied by the hydroxyl ions, expressed as a
tanning liquors,
percentage, is the basicity. The basicity of a chrome tanning P 5 precision of basicity in basic chromium tanning
B
liquid is closely related to the tanning behavior of th
...