Inco Limited

The International Nickel Company, Inc.

Eric A Devuyst

Victor A Ettel

Bruce R Conard

Branka M Tandi

Ramamritham Sridhar

Juraj Babjak

Charles E O'Neill

John Ambrose

Gerald Vernon Glaum

Alexander Illis

Gyula John Borbely

Marcel Alin Mosoiu

Domenic Canini

Konstantin J Schitka

A cost-effective broad temperature method for removing troublesome low valent sulfur compounds from aqueous streams. The process utilizes sulfur dioxide, oxygen and at least one metal catalyst (which may be added to or already entrained in the aqueous stream) to oxidize the low valent sulfur compounds.

Method for treating aqueous streams containing low valent sulfur compounds

A process in which ferric ion in water-soluble form is added to an effluent containing cyanide, arsenic and antimony and having a pH of about 5 to 9 and treating effluent with SO.sub.2 and oxygen in the presence of soluble copper to produce a treated effluent having very low contents of cyanide, arsenic and antimony.

Effluent treatment

A process for treatment of cyanide-containing aqueous effluents in which ferrocyanide present is precipitated with a metal other than copper, preferably zinc either prior to or simultaneously with the treatment of the effluent with sulfur dioxide and air in the presence of soluble copper.

Treatment of cyanide-ferrocyanide effluents

The cyanide content of waste waters containing the same is removed by treatment with sulfur dioxide or an alkali or alkaline earth metal sulfite or bisulfite in the presence of excess oxygen and a metal catalyst which is perferably copper.

Cyanide removal from aqueous streams

Cobalt salts are produced by dissolving cobalt metal in hydrochloric acid containing a small amount of thiosulfate ions.

Process of producing cobalt-containing solutions and salts

This invention is concerned with a process for dissolving oxidic trivalent cobalt compounds in hydrochloric acid while avoiding the generation of chlorine. It includes the following steps (a) slurrying in water the trivalent cobalt compound to be dissolved and (b) treating the resulting slurry with a reduction agent from the group consisting of methanol, formaldehyde and formic acid and with hydrochloric acid. The contact of the hydrochloric acid with the slurry should occur in the presence of the reducing agent. The rate of acid addition should be controlled to maintain the slurry at a pH above 1.

Process for production of CoCl.sub.2 solution from cobaltic oxide-hydrate

A cobaltic oxide hydrate is mixed with spent sulfate electrolyte and the slurry is sparged with air to liberate any entrained chloride ions as gaseous chlorine. Thereafter a reducing agent is used to enable dissolution of the cobalt and obtaining of a chloride-free solution from which, after purification, cobalt can be electrowon.

Process for recovering cobalt electrolytically

A sulfide containing copper and one or more of iron, nickel and cobalt, is dead-roasted at a temperature of 750.degree. C or above, then subjected to a pressure leach under reducing conditions to produce elemental copper and an aqueous solution of the other metals.

Roast-reductive leach process for copper recovery

Copper is separated from nickel present therewith in a sulfate solution by neutralizing to precipitate all the copper and some nickel as basic compounds, and thereafter reducing the copper in the basic compounds to elemental form through formation of cuprous sulfite and thermal dissociation of the latter.

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Toronto, Canada

Eric A Devuyst