AMMONIACAL LEACHING OF SYNTHETIC DELAFOSSITE WITH SPECIAL REFERENCE TO ITS RECOVERY FROM COPPER REVERBERATORY FLUE DUST.

Abstract

A detailed study of the physical and chemical characteristics of a flue dust sample from a coal fired reverberatory furnace was carried out. The characterization studies revealed that cuprous ferrite, delafossite, is one of the major copper bearing constituents in flue dusts collected from copper reverberatory furnaces. A knowledge of the leaching characteristics of delafossite is thus essential to the development of hydrometallurgical techniques for copper recovery from flue dusts. The recovery of copper from synthetic delafossite was investigated using an ammoniacal carbonate solution. The results obtained indicate that the dissolution of delafossite in ammoniacal solution is very slow, but can be dramatically improved by a reductive roast prior to leaching. The kinetics of dissolution of delafossite has been found to strongly depend on the extent of reduction, particle size and stirring speed. It has also been found that applied oxygen pressure increases the rate of dissolution and accentuates the particle size effect. The experimental data seem to fit a film diffusion model. Limited studies have been carried out on the recovery of copper from a flue dust collected from a coal fired reverberatory furnace. Results from these studies have been compared with those obtained for synthetic delafossite.