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Content archived on 2024-06-10

Optimization of gold ores leaching processes in order to reduce environmental hazards


Objectives and content
The gold ores considered as difficult to be processed
include mainly complex ores in which matrix minerals are
sulfides and sulfoarsenides, sometimes associated with
copper minerals. The conventional process is the
cyanidation, which involves for environment and workers
some hazards (emissions of gaseous cyanhydric acid and
liquid wastes).
The objectives of the project are:
to carry out cyanidation in a closed horizontal stirred
grinding mill (HSGM) fed with pumps. The overflow
hazards, which could appear with a conventional ball
mill, should be prevented; moreover, the HSGM behaving
like a quasi-perfect mixer, leaching times and volumes of
liquids should be significantly reduced;
to accelerate cyanidation using catalysts;
to complex gold with reagents other than cyanide
(thiourea and chlorine) of which the effectiveness in
laboratory tests is ascertained but which, in a
conventional technology at industrial scale, are hindered
by the passivation of the gold particles surfaces; that
passivation may be prevented in a stirred mill owing to a
permanent attrition.
The planned investigation consists of:
comparing the technology proposed at laboratory and
pilot scales with the conventional technology in which
grinding in a ball mill and leaching in agitated tanks is
operated successively;
proposing and testing new process flowsheets;
evaluating the process economy.
For that purpose, 3 typical gold materials will be used:
an arsenopyrite flotation concentrate; a gravimetric
mixed concentrate containing free gold and copper; mining
wastes and residues from a roasting and cyanidation
processing operations.

Call for proposal

Data not available


Sofimines-Parmines France
EU contribution
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6 BIS,Avenue Saint Germain
78600 Maison-Laffitte

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Total cost
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Participants (6)