Noranda Inc.

Noranda Mines Limited

Bernard H Morrison

Pierre L Claessens

John L Cromwell

Jack S Stafiej

Viken P Baboudjian

Paul Spira

John G Lenz

J Gerald Bard

Jacques Pageau

A two-stage process for treating anode slimes and other residues containing a substantial amount of nickel without significant dissolution of silver and/or selenium in a single autoclave is disclosed. The process comprises, in a first stage, leaching the anode slimes at 15-30% solids in dilute sulphuric acid at a pressure between 4.0 and 5.5 bars and a temperature between 155.degree. C. to 170.degree. C. in the absence of oxygen to solubilize nickel, and in a second stage, without performing a solid liquid separation, leaching the remaining solids at a pressure between 2 and 3.5, preferably about 2.8 bars and a temperature between 110.degree. and 140.degree. C., preferably about 120.degree. C. with oxygen sparging such that the final sulphuric acid concentration is not less than 50 gpl to solubilize copper and tellurium.

Treatment of high nickel slimes

A continuous silver refining cell comprises a tank containing an electrolyte, at least one vertical cathode disk mounted on a rotating horizontal shaft placed above the tank so that slightly less than half of the disk is immersed in the electrolyte, at least one anode basket containing impure silver anodes immersed in the electrolyte adjacent the cathode disk, and a diaphragm separating the cathode disk from the anode basket to form cathode and anode compartments. A scraper is provided for continuously removing pure silver crystals from the cathode and directing it to the side of the cell. A chain tubular conveyor may be provided for continuously or semi-continuously withdrawing a mud containing gold and other precious metals from the bottom of the cell.

Continuous silver refining cell

A process for treating anode slimes originating from copper, lead or nickel electrorefining to recover the precious metals contained therein is disclosed. The process comprises the steps of charging the slimes into a tiltable and rotatable top blown rotary converter (TBRC), smelting the slimes in the TBRC while it is rotated on an axis inclined to the horizontal to form a slag phase and a precious metals containing phase, tilting the TBRC and skimming the slag produced during smelting, and blowing an oxidizing gas onto or into the precious metals containing phase remaining in the TBRC while rotating the same on its axis inclined to the horizontal to remove impurity elements some of which enter a gas phase and some a new slag phase until a precious metals containing bullion suitable to be treated in a parting plant is obtained.

Treatment of anode slimes in a top blown rotary converter

Slimes from electrolytic copper refinery are first treated by leaching them with dilute sulphuric acid under an oxygen partial pressure of up to 50 psi and an elevated temperature, until copper and tellurium present in the slimes are substantially dissolved, and effecting a liquid-solid separation of the leached slurry so produced to separate the leach liquor from the leach slimes. The leach liquor is then treated with metallic copper to cement the tellurium as copper telluride. The latter is separated from the remaining solution which is suitable for the production of copper sulphate. The leach slimes containing mainly selenium, lead, silver, gold and other impurities are dried, mixed with a binder and pelletized and the pellets are then roasted to remove selenium as selenium dioxide. Finally, the roasted pellets are smelted to remove the remaining impurities leaving a dore metal containing essentially silver and gold.

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Mississauga, Canada

Bernard H Morrison