Selective Reduction of Cu, Ni & Co from Aqueous Solutions through Hydrothermal Route for Production of Metal Powders

Abstract

Rapid depletion of high grade ores of Cu, Ni, and Co, coupled with stringent environmental regulations necessitates recovering these metals from various low grade ores, secondaries, wastes, residues/sludges, effluent streams, etc. Hydrometallurgical processes by far, have been proved to be the most efficient one for treatment of such low grade and waste materials for recovering these metals. The major advantages of hydrometallurgical processes include their flexibility, adaptability, and low capital and energy requirements; above all they are environmentally friendly. Traditional hydrometallurgical processes based on leaching – solvent extraction – electrolysis though capable of producing high pure metals from such low grade and waste sources, but new approaches still need to be explored to make these processes more economically competitive. One of the options in this regard is to produce high pure metal powders, rather than metal sheets or ingots. Powders of Cu, Ni, Co, etc. with desired purity, size and shape found enormous high value powder metallurgical applications such as: specialty alloys, composites & infiltrates, self-lubricating bearings, welding electrodes, numbers of electric and electronic components, medicines, etc., to mention a few. Therefore, the main objective of this study is to explore innovative processing methods for hydrometallurgical production of copper, nickel and cobalt powders from various low grade and waste sources.