A comprehensive review on the hydro metallurgical process for the production of nickel and copper powders by hydrogen reduction

Production of nickel and copper powders from leach solutions and other aqueous streams by hydrogen reduction under pressure has been reviewed in the present paper. By optimising the optimum process condition, powders or composite materials of required specification could be produced from different types of acidic and alkaline solutions by coating nickel or copper powders on the secondary materials such as graphite, tungsten carbide and aluminium. The paper also highlights the kinetics of reduction and the use of various inorganic and organic additives to improve the quality of the powder on bench and commercial scale. Effect of various experimental factors such as pH of the solution, concentration of metals, particle size and nature of additives, operating condition of autoclave, etc. on the rate of reduction and quality of powder are also discussed. (c) 2005 Elsevier Ltd. All rights reserved.