Studies on ammoniacal leaching of copper oxide minerals

Abstract

Aqueous ammoniacal leaching of an oxidized copper ore from the mines of M/s Hindustan Copper Limited : Malanjkhand are reported. Factors which influence copper recovery such as ammonia concentration, solid-liquid ratio, particle size and agitation have been studied at ambient temperature. Over 90% copper extraction could be achieved at 1.5 mo1ar concentration of ammonia, 10% solids and at a stirring speed of 550 Min- . A kinetic study of the process indicated a mixed control reaction mechanism. The copper ammine solution obtained in the leaching step was subjected to precipitation by stripping of the ammonia at different temperatures and air flow rates. The kinetic treatment of the data obtained on preci[litation process revealed that the decomposition reaction is controlled by chemical reaction control. The precipitated product analysed 75% Cu with a recovery of 80-85% copper.