Other

Morris J Beattie

Rein Raudsepp

Ernest Peters

Jean P Duteroue

Arsenopyrite is separated from a mixture with pyrite by contacting the mixture with a sulfitic agent providing HSO.sub.3.sup.- ions at elevated temperature and pH below about 8 for a period sufficient to impart a selective depression property to the arsenopyrite. On addition of a collector the pyrite is rendered floatable, enabling froth flotation to achieve a concentrate rich in pyrite and tailings rich in arsenopyrite.

Flotation separation of arsenopyrite from pyrite

This invention is directed to an improved process for leach treating gold and silver bearing pyritic and arsenopyritic concentrates and ores. More particularly, the improved process avoids the necessity of adding recycled neutralized solution to the leach solution, thereby alleviating difficulties in maintaining acid levels in the leach solution, and provides for bleeding solutions containing dissolved arsenic, iron and sulphate from the process without the loss oxidized nitrogen species. The process can be carried out in one or more tubular reactors. The process for recovering valuable metals from pyritic and arsenopyritic concentrates and ores involves decomposing the arsenopyrite or pyrite concentrates and ores in acidic solution in a common volume space which contains a gas phase and a liquid slurry (which comprises a liquid phase and a solid phase) through the action of higher valence oxidized nitrogen species in which the nitrogen has a valence of at least plus 3. The active oxidized nitrogen species are regenerated in the same common volume space by an oxygen containing gas. The concentrate or ore is introduced into a denitrating step along with a solution from the leach solution. Essentially all of the oxidized nitrogen species in the leach solution is reacted with concentrate or ore to produce in the denitrating step nitric oxide which is released into an oxygen free gas phase and is transported to the gas phase of the common volume species. The liquid and solid products of the denitrating step are subjected to a solid-liquid separation, after which the solids from the separation step are transported to a leaching vessel where the solids are treated with oxygen and nitric oxide replaced from the denitrating step.

Hydrometallurgical process for treating refractory ores containing

A process for the hydrometallurgical recovery of precious metal from an ore or concentrate containing at least some arsenopyrite or pyrite. The process comprises forming in a common volume space a gas phase and a liquid slurry comprising the ore or concentrate as the solid phase and acid and water as the liquid phase of the slurry effecting in the slurry an oxidation-reduction reaction between the arsenopyrite or pyrite and an oxidized nitrogen species in which the nitrogen has a valence of at least plus 3 thereby solubilizing in the liquid phase the arsenic, iron and sulphur in the arsenopyrite, or the iron and sulphur in the pyrite, and producing in the liquid phase nitric oxide in which the nitrogen has a valence of plus 2; releasing at least part of the nitric oxide from the liquid phase into the gas phase oxidizing the nitric oxide in the gas phase, to form an oxidized nitrogen species in which the nitrogen has a valence of at least plus 3; and absorbing the oxidized nitrogen species into the slurry wherein the oxidized nitrogen species become available for the oxidation-reduction reaction. The resultant treated slurry is subjected to a solid-liquid separation to produce a solid residue and a liquid fraction. Precious metal is recovered from the solid residue. The liquid fraction is recycled in the process.

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Vancouver, Canada

Morris J Beattie