Material Balance Approach for Parameter Determination in Bioleaching Process

Abstract The Kasese Cobalt Company - Limited (KCCL) plant reprocesses a pyrite concentrate produced and stockpiled during the operation of the Kilembe copper mine (Uganda). This concentrate, prior to the KCCL operations, was causing an environmental damage to the Queen Elisabeth National Park since the 70s. The KCCL bioleaching process aims at extracting the valuable cobalt trapped in sulfide minerals by destroying the mineral matrix, thus avoiding further pollution from these sulfides. Both for economic and environmental reasons the process has to oxidize a maximum of sulfides. Embedded in a relatively complex flowsheet, the evaluation of performances of the bioleaching stage represents a real challenge, considering the poor level of instrumentation in this section and the sampling difficulties. In this case, the use of a material balance algorithm represented the only efficient tool for estimating performances of the different process stages and identifying the possible optimization points. Using the BILCO™ software package, developed by BRGM, a specific tool has been created in the Microsoft Excel environment for the automation of the mass balance computation and of the main operating parameter determinations. After a short recall of the material balance theory, the paper presents the KCCL plant process and the application developed for the material balance of this specific circuit. It shows how the non-measurable parameters can be obtained by the aid of the application.