Sulphation roasting studies on synthetic copper-iron sulphides with steam and oxygen

The direct sulphation of individual and mixed sulphides of copper and iron has been studied using a steam-oxygen mixture as the oxidant. The investiga tion showed that copper sulphide formed copper sulphate with this gaseous m ixture at 773 K, whereas iron sulphide converted mostly to hematite at this temperature. It was also observed that the mixture of copper-iron sulphide s yielded a higher amount of copper sulphate (92.7%) than that obtained (40 .0%) from copper sulphide alone in the presence of 10 wt.% ferric oxide. Th is was mainly attributed to an improved sulphatising environment during the roasting of mixed sulphides. The kinetics study of the CuS-FeS system with a steam-oxygen mixture showed that the copper sulphate formation followed the topochemical model. An activation energy value for this conversion was found to be 30.36 kJ/mol in the temperature range 673 to 773 K. The sulphid es and different calcined products obtained were characterised by X-ray dif fraction (XRD), Scanning Electron Microscopy (SEM) and the metallographic s tudies to examine the path of reaction. (C) 2000 Canadian Institute of Mini ng and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.