ASTM E1568-93(1998)
(Test Method)Standard Test Method for the Determination of Gold in Activated Carbon by Fire Assay Gravimetry
Standard Test Method for the Determination of Gold in Activated Carbon by Fire Assay Gravimetry
SCOPE
1.1 This test method covers the determination of gold in activated carbon by fire assay collection and gravimetric measurement. It covers the range of 15 to 5000 [mu]g/g gold.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety problems, 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. For specific hazards statements, see Section 9 and Notes 2 through 4 and 6 and 7.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1568 – 93 (Reapproved 1998)
Standard Test Method for
Determination of
Gold in Activated Carbon by Fire Assay Gravimetry
This standard is issued under the fixed designation E 1568; 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 3. Terminology
1.1 This test method covers the determination of gold in 3.1 Definitions:
activated carbon by fire assay collection and gravimetric 3.1.1 draft, n—in fire assay, the control of air flow through
measurement. It covers the range of 15 to 5000 μg/g gold. a muffle furnace.
1.2 The values stated in SI units are to be regarded as the
4. Summary of Test Method
standard. The values given in parentheses are for information
4.1 The weighed test sample is ignited and fused with fire
only.
1.3 This standard does not purport to address all of the assay flux in a clay crucible. The lead metal from the fusion is
separated and the precious metals concentrated by oxidation
safety problems, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- and adsorption of the lead on a cupel, the silver is parted with
nitric acid, and the gold is annealed and weighed on a
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific hazards microbalance.
statements, see Section 9 and Notes 2-4, Note 6, and Note 7.
5. Significance and Use
2. Referenced Documents
5.1 In the primary metallurgical processes used by the
mineral processing industry for gold bearing ores, gold is
2.1 ASTM Standards:
D 2862 Test Method for Particle Size Distribution of extracted with alkaline cyanide solutions and adsorbed onto
activated carbon for recovery of the metal. Metallurgical
Granular Activated Carbon
D 2866 Test Method for Total Ash Content of Activated accounting, process control, and ore evaluation procedures for
this type of mineral processing plant depend on accurate,
Carbon
D 2867 Test Method for Moisture in Activated Carbon precise, and prompt measurements of gold concentrations in
the activated carbon.
E 29 Practice for Using Significant Digits in Test Data to
Determine Conformance with Specifications 5.2 This test method for gold in activated carbon is intended
primarily as a referee method to test such materials for metal
E 50 Practices for Apparatus, Reagents, and Safety Precau-
tions for Chemical Analysis of Metals content. It is assumed that those who use these procedures will
be trained analysts capable of performing common laboratory
E 173 Practice for Conducting Interlaboratory Studies of
procedures skillfully and safely. It is expected that work will be
Methods for Chemical Analysis of Metals
E 276 Test Method for Particle Size or Screen Analysis at performed in a properly equipped laboratory and that proper
waste disposal procedures will be followed. Appropriate qual-
No. 4 (4.75 mm) Sieve and Finer for Metal-Bearing Ores
and Related Materials ity control practices must be followed, such as those described
in Guide E 882.
E 300 Practice for Sampling Industrial Chemicals
E 882 Guide for Accountability and Quality Control in the
6 6. Interferences
Chemical Analysis Laboratory
6.1 Elements normally found in ore processing activated
carbon do not interfere. When present, platinum group metals
may be reported as gold in gravimetric fire assay determina-
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
tions and must be less than 0.1 mg in the final gold bead.
responsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-
lurgical Materials.
7. Apparatus
Current edition approved Sept. 15, 1993. Published November 1993.
7.1 Analytical Balance, capable of weighing to 0.1 g.
Annual Book of ASTM Standards, Vol 15.01.
Annual Book of ASTM Standards, Vol 14.02.
7.2 Assay Mold, 100-mL capacity.
Annual Book of ASTM Standards, Vol 03.05.
7.3 Cupel, magnesite, 30-g lead capacity.
Annual Book of ASTM Standards, Vol 15.05.
Annual Book of ASTM Standards, Vol 03.06.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1568
7.4 Drying Oven, having forced air circulation, with tem- 10. Sampling
perature control between 145 and 155°C.
10.1 Collect the sample in accordance with Practice E 300.
7.5 Fire Clay Crucible, 30-g sample capacity.
Samples must be free of any extraneous materials such as sand,
7.6 Hot Plate, having variable temperature control, used
rocks, and wood.
with ventilation control for acid fumes.
10.2 Sample Preparation—Dry the sample, in accordance
7.7 Jeweler’s Rolls, capable of flattening doré beads.
with the Oven-Drying Method of Test Method D 2867, to
7.8 Muffle Furnace, having air circulation with draft con-
constant weight at 150°C. If the analysis of a particular particle
trols, capable of temperatures to 1100°C, accurate to 6 10°C,
size range is desired, separate fractions in accordance with Test
used with ventilation controls for lead fumes.
Method D 2862.
7.9 Semi-Microbalance, capable of weighing to 0.01 mg.
10.3 Test Sample—Pulverize the gross sample so that at
7.10 Roasting Dish, 15-g sample capacity.
least 90 % passes a 150-μm (100 mesh, Tyler) sieve, in
accordance with Test Method E 276. Mix the gross sample.
8. Reagents
Weigh duplicate test samples of 15.0 6 1.0 g, and record the
8.1 Purity of Reagents—Reagent grade chemicals shall be
test sample weights.
used in all tests. Unless otherwise indicated, it is intended that
11. Procedure
all reagents shall conform to the specifications of the Commit-
tee on Analytical Reagents of the American Chemical Society,
11.1 Ignition:
where such specifications are available. Other grades may be
11.1.1 Spread5gof silica (SiO ) in the bottom of a
used, provided it is first ascertained that the reagent is of
preheated roasting dish.
sufficiently high purity to permit its use without lessening the
11.1.2 Transfer the test sample to the top of the silica bed in
accuracy of the determination.
the roasting dish.
8.2 Ammonia Wash Solution,NH OH (1 + 17)—Add 100
4 11.1.3 Ash at 650°C in a muffle furnace in accordance with
mL ammonium hydroxide to 1700 mL of H O.
Test Method D 2866. Cool.
8.3 Borax—Na B O —Sodium borate powder, with gold
2 4 7 11.2 Fusion:
content less than 0.001 μg/g.
11.2.1 Transfer calcine and silica to a clay crucible contain-
8.4 Fire Assay Flux Mixture—Mix 575 g of litharge (PbO)
ing 50 g of fire assay flux.
with 275 g of soda ash (Na CO ), 75 g of borax (Na B O ), 75
11.2.2 Cover with another 50 g portion of fire assay flux.
2 3 2 4 7
g of silica (SiO ), and 30 g of baking flour.
2 Mix. Cover the mixture of5gof litharge (PbO).
8.5 Lead Foil—99.9 % minimum, with gold content less
11.2.3 Place the
...
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