Abstract: A method for preventing the formation of jarosite, ammonium and alkali metal double salts during solvent extraction and leaching of an acidic leaching process in which an aqueous solution containing at least two metals are separated selectively from each other, and ammonium and alkali salts in the solution are neutralized prior to separation of the metals from the solution, and the formation of harmful double salts are prevented by using an exchange ion, which includes separating a first metal of the at least two metals by solvent extraction after neutralizing the solvent extraction solution by means of ammonium or alkali base; contacting the extraction solution with an aqueous solution containing an exchange ion, and replacing the ammonium or alkali ions contained in the extraction solution with the metal exchange ion during a pre-extraction step, whereby the ammonium or alkali ions are transferred into the aqueous solution to prevent formation of ammonium and alkali based double salts in a leach process sol

Abstract: The invention relates to a method for fully beneficating nickel sulfide concentrates or other corresponding mixtures, unsuitable for smelting, by combining the use of both pyrometallurgical and hydrometallurgical processes, so that there are formed two separate concentrates, the first of which is suited to pyrometallurgical and the second to hydrometallurgical treatment. In the concentrate going to pyrometallurgical processing, the valuable metal content increases as a consequence of the treatment, and the Fe/MgO ratio of this concentrate is at least 2.6.

Abstract: The invention relates to a method for producing high-grade nickel matte and highly oxidized slag in a flash smelting furnace, and for reducing the slag from the flash smelting furnace and for sulfurating the created matte in an electric furnace. The matte created in the flash smelting furnace and in the electric furnace are both directly conducted to hydrometallurgical further treatment.