ASTM E342-99

Standard Test Method for Chromium Oxide in Chrome Ores

SCOPE
1.1 This test method covers the determination of chromium oxide (Cr 2 O 3 ) in chrome ores in the concentration range from 25 to 60%.
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: 09-Nov-1999
• ICS: 73.060.30 - Chromium ores
• Technical Committee: E01 - Analytical Chemistry for Metals, Ores, and Related Materials
• Drafting Committee: E01.02 - Ores, Concentrates, and Related Metallurgical Materials

Relations

• Replaced By: ASTM E342-04 - Standard Test Method for Determination of Chromium Oxide in Chrome Ores by Permanganate Titrimetry
• Effective Date: 01-May-2004
• Referred By: ASTM E1282-21 - Standard Guide for Specifying the Chemical Compositions and Selecting Sampling Practices and Quantitative Analysis Methods for Metals, Ores, and Related Materials
• Effective Date: 10-Nov-1999

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: E 342 – 99
Standard Test Method for
Determination of Chromium Oxide in Chrome Ores by
Permanganate Titrimetry
This standard is issued under the fixed designation E 342; 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 analysts capable of performing common laboratory procedures
skillfully and safely. It is expected that work will be performed
1.1 This test method covers the determination of chromium
in a properly equipped laboratory and that proper waste
oxide (Cr O ) in chrome ores in the concentration range from
2 3
disposal procedures will be followed. Appropriate quality
25 to 60 %.
control practices must be followed such as those described in
1.2 This standard does not purport to address all of the
Guide E 882.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Interferences
priate safety and health practices and determine the applica-
5.1 None of the elements normally found in chrome ores
bility of regulatory limitations prior to use.
interfere with this test method.
2. Referenced Documents
6. Reagents and Materials
2.1 ASTM Standards:
6.1 Purity and Concentration of Reagents—The purity and
E 50 Practices for Apparatus, Reagents, and Safety Precau-
2 concentration of the common chemical reagents used shall
tions for Chemical Analysis of Metals
conform to Practices E 50. Special apparatus and reagents
E 276 Test Method for Particle Size or Screen Analysis at
required are located in separate sections preceding the proce-
No. 4 (4.75-mm) Sieve and Finer for Metal-Bearing Ores
dure.
and Related Materials
6.2 Ammonium Peroxydisulfate Solution (250 g/L)—
E 882 Guide for Accountability and Quality Control in the
Reagent No. 106 (see Practices E 50).
Chemical Analysis Laboratory
6.3 Ferrous Ammonium Sulfate, Standard Solution (0.2
3. Summary of Test Method N)—Dissolve 78.4 g of ferrous ammonium sulfate
(FeSO (NH ) SO ·6H O) in 1 L of cool H SO (5+95). As the
4 2 4 2 2 4
3.1 The sample is decomposed by fusion with sodium
ferrous ammonium sulfate solution gradually weakens in
peroxide. After leaching in water and boiling to decompose
reducing power, it is necessary to standardize it daily, or at the
peroxides, the solution is acidified with nitric and sulfuric
same time that the chrome ore is analyzed. To standardize,
acids. Residual chromium is oxidized to chromate with silver
transfer 100 mL of FeSO (NH ) SO ·6H O to a 600-mL
4 4 2 4 2
nitrate, potassium permanganate, and peroxydisulfate. The
beaker, dilute to 300 mL with cold H SO (5+95), add 2 mL of
excess of permanganate is destroyed by the addition of sodium 2 4
H PO and 2 drops of ortho-phenanthroline ferrous sulfate
3 4
chloride. After cooling, the chromate is reduced by the addition
(Ferroin). Titrate immediately with 0.2 N KMnO solution to
of a measured excess of a ferrous ammonium sulfate, and the 4
a faint, permanent pink color.
excess titrated with a standard permanganate solution.
6.4 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
4. Significance and Use
(HNO ).
6.5 Ortho-Phenanthroline Ferrous Sulfate Indicator Solu-
4.1 This test method is intended to be used for compliance
tion —(0.025 M)—Reagent No. 122 (see Practices E 50).
with compositional specifications for chromium oxide content.
6.6 Phosphoric Acid (sp gr 1.69)—Concentrated phosphoric
It is assumed that all who use these procedures will be trained
acid (H PO ).
3 4
6.7 Potassium Permanganate Solution (20 g/L)—Reagent
No. 134.
This test method is under the jurisdiction of ASTM Committee E-1 on
Analytical Chemistry for Metals, Ores, and Related Materials and is the direct 6.8 Potassium Permanganate, Standard Solution (0.2 N)—
responsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-
Dissolve 6.4 g of KMnO in 1 L of water. Standardize against
lurgical Materials.
Current edition approved Nov. 10, 1999. Published January 2000. Originally
published as E 342 – 67 T. Last previous edition E 342 – 94 .
2 4
Annual Book of ASTM Standards, Vol 03.05. Ferroin indicator distributed by G. F. Smith Chemical Co. has been found to be
Annual Book of ASTM Standards, Vol 03.06. acceptable.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E 342
the National Institute of Standards and Technology Standard color. The FeSO (NH ) SO ·6H O may be added either as 1.2
4 4 2 4 2
sodium oxalate or equivalent. N solution or a weighed amount of the salt (Note 3). Add 2
6.9 Silver Nitrate Solution (8 g/L)—Reagent No. 133 (see drops of orthophenanthroline ferrous sulfate (Ferroin) as an
Practices E 50). indicator. Titrate the excess FeSO (NH ) SO ·6H O with 0.2
4 4 2 4 2
6.10 Sodium Chloride Solution (100 g/L)—Dissolve 10 g of N KMnO solution. The end point is reached when the solution
sodium chloride (NaCl) in water and dilute to 100 mL. becomes clear green in color.
6.11 Sodium Peroxide (Na O ).
2 2
NOTE 3—Approximately 70 mL of 0.2 N FeSO (NH ) SO ·6H O
4 4 2 4 2
...