Production of nickel powder from impure nickel compounds

Abstract

Abstract According to the invention, substantially pure, particulate elemental nickel is recovered from nickel compounds and particularly from basic nickel carbonate, which are soluble in aqueous ammoniacal ammonium sulphate solution and which contain impurities including particularly zinc, manganese and/or magnesium by first extracting substantially all the nickel content from the impure nickel compound by dissolving it in an aqueous ammoniacal ammonium sulphate solution containing ammonium sulphate in excess of the stoichiometric amount required to react with the nickel to form nickel diammine sulphate. The resulting nickel diammine sulphate solution is separated from undissolved residue and is reacted with hydrogen at elevated temperature and pressure to reduce dissolved nickel to elemental form and to precipitate it in powder form. Nickel-depleted solution, referred to as ''''reduction end solution,'''' containing zinc, manganese and/or magnesium as well as small amounts of other impurities as dissolved sulphates is recycled to the nickel compound dissolution step and the quantity of such solution recycled is controlled such that the impurities'' level in the reduction end solution is maintained at a predetermined level above the level that would result if no solution were recycled but below that level at which zinc, manganese and/or magnesium report in the nickel powder product in sufficient quantity to contaminate the product. The portion of the reduction end solution which is not recycled is bled from the process circuit.

Inventors

• 👤 D Evans
• 👤 D Maschmeyer
• 👤 V Mackiw
• 👤 D Weir

Bibliographic Details