Anglovaal Mining Limited (Avmin) is increasing production at the Chambishi Metals Cobalt Plant in Zambia through its COSAC Project. The increase in cobalt and copper production will increase the nickel input to the cobalt purification circuit. In order to maintain electrowon cobalt metal quality, it is therefore necessary to remove this nickel from the cobalt advance electrolyte.
Laboratory testwork showed that expansion of the existing fixed bed nickel ion exchange operation with one additional column could not guarantee the requirements for the maximum allowable nickel concentration in the cobalt electrolyte. The addition of more than one column would have been capital intensive and not feasible from an economic point of view, and therefore, it was decided to evaluate continuous nickel ion exchange using ISEP® Carousel technology. An initial analysis showed that this approach was both technically and economically the most attractive.