Process for removing manganese from organic solutions of oximes and nickel ore treatment process

A process for the extraction of nickel from nickel-containing ores that also contain manganese values comprising the steps of:

• (a) leaching the nickel-containing ore with an acid to provide an aqueous acid leach solution containing nickel values along with other metal values including manganese values;
• (b) adding a hydroxide or hydroxide precursor to the aqueous acid leach solution to precipitate the nickel as nickel hydroxide;
• (c) re-leaching the nickel hydroxide with an aqueous ammoniacal solution to provide an aqueous ammoniacal solution containing metal values including the nickel values;
• (d) contacting the aqueous ammoniacal solution containing the nickel values and manganese values with a water insoluble oxime extractant, capable of extracting nickel from said aqueous ammoniacal solution, comprising an oxime extractant dissolved in a water-immiscible hydrocarbon solvent so as to provide an organic phase, for a time sufficient to extract the nickel values from said aqueous ammoniacal solution containing the nickel values thereby providing an aqueous phase of the ammoniacal solution from which nickel values have been removed and a water-immiscible organic phase containing the extracted nickel values and at least some of the manganese values;
• (e) separating the aqueous and the water-immiscible organic phases;
• (f) contacting the organic phase containing the nickel values and manganese values with an aqueous acid stripping solution thereby stripping the nickel values from the water-immiscible organic phase into the aqueous acid stripping solution;
• (g) separating the aqueous acid stripping solution now containing the nickel values from the water-immiscible organic phase which contains manganese values;
• (h) electrowinning the nickel from the aqueous acid stripping solution to remove and recover the nickel;
• and either before or after step (h),
• (i) mixing the water-immiscible organic phase which contains manganese values which were not removed by the aqueous acid stripping solution in step (f) with an active metal in finely divided form together with an aqueous solution of a strong acid to decrease or completely remove the manganese values from the water-immiscible organic phase, and
• (j) separating the resulting manganese depleted water-immiscible organic phase from the aqueous solution of a strong acid.