Inco Limited

Solarchem Enterprises Inc.

Goro Nickel S.a.

Cuong V Luong

Eberhard Krause

Indje O Mihaylov

Steve W Laundry

Keith G Bircher

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.

A process is provided for treating aqueous waste or groundwater contaminated with nitro-containing organic chemicals to degrade the compound sufficiently to permit disposal of the waste or groundwater.

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Mississauga, Canada

Cuong V Luong