Modeling the auto-thermal performance of a thermophilic chalcopyrite bioleaching heap employing mesophilic and thermophilic microbes

A model was prepared to study the performance of a thermophilic bioleaching heap that employs mixed mesophilic and thermophilic microbes for copper extraction from CuFeS₂. Mesophiles' preference for and ease of dissolving additional FeS₂ provided to the heap enables the transition from a mesophilic to a thermophilic bioleaching state without the necessity of additional energy supply. In this sense, the mathematical description of the bioleaching process is done taking into consideration the dependency of both microbes' biological states on physicochemical factors such as the temperature and O₂ availability. With regard to the flow rates of the liquid and air phases, simulation results have shown that these flow rates govern not just the heat transfer and variation of cell distribution, but also the leaching rate regardless of the fraction of CuFeS₂ per FeS₂ leached (FCP) which is the other variable influencing to the heat accumulation in the heap.