Patents
The invention provides a process for the preparation of copper and nickel powder from the impurity-laden copper bleed electrolyte generated from the electrolytic tank directly by hydrogen reduction under pressure. Copper powder was selectively produced first in an autoclave under certain pressure and temperature till all the copper present in the solution is reduced into metallic form. The mother liquor is then treated with sodium sulphide to precipitate out the copper present in traces. The copper free mother liquor is evaporated to form nickel sulphate crystals. This nickel sulphate is then dissolved in ammonia. A known amount of this solution is then taken in a Teflon lined vessel and pressurised with hydrogen gas to yield pure nickel Powder. The Copper powder formed was washed with distilled water followed by sodium carbonate solution and then with distilled water again. It was finally treated with sodium potassium tartarate before drying and storing. The nickel powder produced is washed with acidic water to neutralise ammonia adhering to the surface of the nickel powder formed, then with distilled water and finally with a solution of sodium potassium tartrate to restrict oxidation of the metal powder and dried at 100°C to produce a high pure powder for P/M applications.