ASTM E316-00

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Designation: E 316 – 00
Standard Test Method for
Determination of Iron in Manganese Ores by Hydrogen
Sulfide Reduction-Dichromate Titration
This standard is issued under the fixed designation E 316; 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 nese ores. It is assumed that all who use these procedures will
be trained analysts capable of performing common laboratory
1.1 This test method covers the determination of iron in
proceduresskillfullyandsafely.Itisexpectedthatworkwillbe
manganese ore in the range from 2 to 20 %.
performed in a properly equipped laboratory and that proper
1.2 This standard does not purport to address all of the
waste disposal procedures will be followed. Appropriate qual-
safety concerns, if any, associated with its use. It is the
ity control practices must be followed such as those described
responsibility of the user of this standard to establish appro-
in Guide E 882.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
6. Interferences
2. Referenced Documents 6.1 None of the elements normally found in manganese ore
interfere with this test method.
2.1 ASTM Standards:
E 50 Practices for Apparatus, Reagents, and Safety Precau-
7. Reagents and Materials
tions for Chemical Analysis of Metals
7.1 Purity and Concentration of Reagents—The purity and
E 135 Terminology Relating to Analytical Chemistry for
concentration of the common chemical reagents used shall
Metals, Ores, and Related Materials
conform to Practices E 50. Special apparatus and reagents
E 882 Guide for Accountability and Quality Control in the
required are located in separate sections preceding the proce-
Chemical Analysis Laboratory
dure.
3. Terminology 7.2 Ferrous Ammonium Sulfate Solution (approx. 0.10
N)—Dissolve 40 g of ferrous ammonium sulfate
3.1 Definitions—For definitions of terms used in this test
(FeSO (NH ) SO ·6H O)insulfuricacid(1+19).Transfertoa
method, refer to Terminology E 135. 4 2 4 2
1-L flask and dilute to volume with the same acid. When the
4. Summary of Test Method sample solution is ready for titration, standardize the
FeSO (NH ) SO ·6H O solution against the standard potas-
4.1 The sample is decomposed by treatment with hydro- 4 2 4 2
sium dichromate solution (0.1000 N) as described in 11.1.
chloric, hydrofluoric, and sulfuric acids.Any residue is treated
Calculate the millilitres of standard potassium dichromate
for the recovery of insoluble iron. The iron is reduced with
solution equivalent to 1 mL of the FeSO (NH ) SO ·6H O
hydrogen sulfide, the insoluble sulfides are removed by filtra- 4 4 2 4 2
solution.
tion, and the excess hydrogen sulfide is expelled by boiling.
7.3 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
After cooling, the reduced iron is titrated with a standard
chloric acid (HCl).
potassium dichromate solution using sodium diphenylamine
7.4 Hydrofluoric Acid (48 %)—Concentrated hydrofluoric
sulfonate as the indicator.
acid (HF).
5. Significance and Use
7.5 Hydrogen Sulfide (H S).
7.6 Hydrogen Sulfide Wash Solution.
5.1 This test method is intended to be used for compliance
7.6.1 Saturate H SO (1+99) with hydrogen sulfide (H S).
with compositional specifications for iron content in manga- 2 4 2
Prepare fresh as needed.
7.7 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
This test method is under the jurisdiction of ASTM Committee E01 on
(HNO ).
Analytical Chemistry for Metals, Ores, and Related Materials and is the direct
7.8 PhosphoricAcid(85 %)—Concentratedphosphoricacid
responsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-
(H PO ).
lurgical Materials.
3 4
Current edition approved Nov. 10, 2000. Published January 2001. Originally
7.9 Potassium Dichromate, Standard Solution (0.1000 N)
published as E 316 – 67 T. Last previous edition E 316 – 95a.
Annual Book of ASTM Standards, Vol 03.05.
Annual Book of ASTM Standards, Vol 03.06.
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E 316
7.9.1 Dissolve 4.9035 g of Primary Standard Grade potas- Dissolve the cool melt in a few millilitres of water and add this
sium dichromate (K Cr O ) in water, transfer to a 1-L volu- solution and the washings of the crucible and cover to the
2 2 4
metric flask, dilute to volume, and mix. reserved filtrate.
7.10 Sodium Diphenylamine Sulfonate Indicator Solution (2 10.5 Dilute the solution with water to a volume of 250 mL
and heat to boiling. Remove from the heat source and pass a
g/L).
rapid stream of H S through the solution for 15 min. Digest at
7.10.1 Dissolve 0.20 g of sodium diphenylamine sulfonate
60°Cfor15minandfilterthroughamediumtexturepaperwith
in 100 mL of water. Store in a dark-colored bottle.
theaidofpaperpulpintoa500-mLErlenmeyerflask.Washthe
7.11 Sodium Pyrosulfate (Na S O ).
2 2 7
precipitatedsulfidesthoroughlywiththehydrogensulfidewash
7.12 Sulfuric Acid (sp gr 1.84)—Concentrated sulfuric acid
solution. Add a few glass beads to the flask to prevent
(H SO ).
2 4
bumping, heat the solution to boiling, and boil for 15 to 20 min
7.13 Sulfuric Acid (1+1)—Mix 1 volume of concentrated
to completely expel the H S. (Check with lead acetate test
H SO (sp gr 1.84) with 1 volume of water.
paper.) Remove from the heat source, cover the flask with a
7.14 Sulfuric Acid (1+19)—Mix 1 volume of concentrated
small watch glass, and cool to 20°C in running water.
H SO (sp gr 1.84) with 19 volumes of water.
10.6 To the cool solution add 5 mL
...