Inco Limited

Goro Nickel S.a.

Cytec Technology Corporation

Eberhard Krause

Indje O Mihaylov

Bruce John Love

Cuong V Luong

Avinash Singhal

Derek George Eagland Kerfoot

Steve W Laundry

James A Bell

Juraj Babjak

William A Rickelton

Reichel A Tenbergen

Justin Raskauskas

Yoshiaki Okita

Pak Kuen Louie

Steven W Laundry

Vladimir J Zatka

Brian Charles Blakely

A hydrometallurgical process for the recovery of nickel and cobalt values from a sulfidic flotation concentrate. The process involves forming a slurry of the sulfidic flotation concentrate in an acid solution, and subjecting the slurried flotation concentrate to a chlorine leach at atmospheric pressure followed by an oxidative pressure leach. After liquid-solids separation and purification of the concentrate resulting in the removal of copper and cobalt, the nickel-containing solution is directly treated by electrowinning to recover nickel cathode therefrom.

Hydrometallurgical process for the recovery of nickel and cobalt values from a sulfidic flotation concentrate

The process provides a method of removing arsenic from solutions containing sulfur dioxide in an environmentally acceptable manner. This process first oxidizes arsenic, iron and sulfur dioxide contained in an aqueous solution to prepare the solution for precipitation and to improve process control. Recycled neutralized precipitate seeds the oxidized aqueous solution. A calcium-containing base precipitates products of neutralization on the seeds. The final neutralized precipitate contains a stable ferric arsenate compounds.

Removal of arsenic from iron arsenic and sulfur dioxide containing

The invention provides a method of regenerating dithiophosphorus extractants such as dithiophosphoric acids, dithiophosphonic acids and dithiophosphinic acids from their sulfur-sulfur bonded oxidation products contained in an organic solution. The process generates active hydrogen for regenerating the spent dithiophosphorus extractants. Advantageously, this active hydrogen originates either from introducing a reactive metal into a liquid mixture containing the organic solution and an acidic aqueous solution to form nascent hydrogen or from using hydrogen gas in the presence of a catalyst in the organic solution. The active hydrogen generated in the process breaks the sulfur-sulfur bonds of the dithiophosphorus molecules to form the corresponding dithiophosphorus acids.

Regeneration of dithiophosphorus acid metal extractants

The invention provides an autoclave configuration for pressure leaching lateritic ores at elevated temperatures. The autoclave configuration includes at least one primary autoclave. The primary autoclave includes a slurry inlet port for receiving slurries of lateritic ore from a lateritic slurry supply, an acid inlet port for receiving leaching acids, an agitation means for agitating the slurries of lateritic ore, and an outer port for removing partially leached slurries of lateritic ore. A multi-compartment autoclave follows the primary autoclave. The multi-compartment autoclave is divided into at least two chambers connected in series. The chambers contain a means for agitating the partially leached slurries and divider walls for separating the chambers. An inlet port is connected to the first of the chambers for receipt of the partially leached slurries. An outlet port is connected to the last of the series of chambers for removal of the finally leached slurries. A bypass conduit is connected to the lateritic slurry supply and the multi-compartment autoclave. The bypass conduit is for periodically isolating the primary autoclave for removal of scale while leaching lateritic ore in the multi-compartment autoclave.

Method for acidic leaching of lateritic ores

The invention provides an autoclave configuration for pressure leaching lateritic ores at elevated temperatures. The autoclave configuration includes at least one primary autoclave. The primary autoclave includes a slurry inlet port for receiving slurries of lateritic ore from a lateritic slurry supply, an acid inlet port for receiving leaching acids, an agitation means for agitating the slurries of lateritic ore, and an outlet port for removing partially leached slurries of lateritic ore. A multi-compartment autoclave follows the primary autoclave. The multi-compartment autoclave is divided into at least two chambers connected in series. The chambers contain a means for agitating the partially leached slurries and divider walls for separating the chambers. An inlet port is connected to the first of the chambers for receipt of the partially leached slurries. An outlet port is connected to the last of the series of chambers for removal of the finally leached slurries. A bypass conduit is connected to the lateritic slurry supply and the multi-compartment autoclave. The bypass conduit is for periodically isolating the primary autoclave for removal of scale while leaching lateritic ore in the multi-compartment autoclave.

Apparatus and method for acidic leaching of lateritic ores

The invention provides a hydrometallurgical process for the recovery of metals. In particular, an aqueous feed solution originating from acid leaching is provided. The aqueous feed solution contains nickel and/or cobalt ions. The pH of the solution is maintained at a level between about 2 and 6. The aqueous feed solution is contacted with a water-immiscible organic phase containing an extractant to load the nickel and/or cobalt metal ions to form a metal-bearing organic phase. The extractant has at least one organic soluble dithiophosphinic acid, alkali, alkaline earth metal or ammonium salt thereof. The aqueous feed solution has sufficiently low levels of chromium (VI) ions, iron (III) ions and copper ions to allow repeated use of the extractant. The metal-bearing organic phase is then separated from the metal-containing aqueous feed solution. Finally, after separation from the aqueous feed solution, the metal-bearing organic phase is contacted with an aqueous strip solution to recover the loaded nickel and/or cobalt from the metal-bearing organic phase.

Process for the extraction and separation of nickel and/or cobalt

The invention provides a hydrometallurgical process for the recovery of metals. In particular, an aqueous feed solution derived from acid leaching is provided. The aqueous feed solution contains nickel and/or cobalt ions. The pH of the solution is maintained at a level between about 2 and 6. The aqueous feed solution is contacted with a water-immiscible organic phase containing an extractant to load the nickel and/or cobalt metal ions to form a metal-bearing organic phase. The extractant has at least one organic soluble dithiophosphinic acid, alkali, alkaline earth metal or ammonium salt thereof. The aqueous feed solution has sufficiently low levels of chromium (VI) ions and copper ions to allow repeated use of the extractant. The metal-bearing organic phase is then separated from the metal-containing aqueous feed solution. Finally, after separation from the aqueous feed solution, the metal-bearing organic phase is contacted with an aqueous strip solution to recover the loaded nickel and/or cobalt from the metal-bearing organic phase.

The invention provides a method of forming copper arsenate. Copper and arsenic are leached into a treatment solution maintained at a pH level of about 2 to 5 in the presence of at least one impurity. An oxidant is added to the treatment solution to oxidize the copper and arsenic. A copper arsenate compound is precipitated from the solution as copper arsenate. Preferably, the copper arsenate is then releached in a purification solution. The molar ratio of copper to arsenic is adjusted to a level of at least 2. The pH of the purification solution is then increased to precipitate copper arsenate having a decreased concentration of said at least one impurity. Impure copper arsenate may be suspended and reacted in a recrystallization solution preferably having cupric ion. The pH of recrystallization solution is adjusted to a valve between about 1 and 4.5.

Method for forming copper arsenate

Uranium is leached from water slurries of uranium ore by incorporating a mixture of sulfur dioxide and air therein to provide the oxidizing and acidifying requirements to accomplish leaching.

Leaching of uranium ore

A process for removing sulfur dioxide from industrial gas streams by scrubbing the gas with an aqueous slurry including 2CaO.Fe.sub.2 O.sub.3 (dicalcium ferrite). The 2CaO.Fe.sub.2 O.sub.3 is present in lime slags or flotation tailings derived from non-ferrous smelting operations.

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Oakville, Canada

Eberhard Krause