A Two-Dimensional Model for the Heap Bioleaching of Chalcocite: Effect of Inlet Height

A two-dimensional (2D) model of the heap bioleaching of chalcocite and pyrite is given, which accounts for the placement of spargers inside the heap. The 3-phase finite volume computational fluid dynamics model accounts for the transport of air, liquid and heat in the heap, in addition to the reaction of chalcocite and pyrite in the solid, and attachment of bacteria to the solid phase. This work is concerned with the 2D air flow in the heap, and it is found that the heap leaches in a 2D manner around the air inlet, and in an essentially one-dimensional manner from the top of the heap. In all inlet height cases tested, a leaching front develops from the air inlet which spreads out in all directions, and moves faster below the air inlet, than directly above the inlet. As the air inlet height is increased, the leaching is more extensive at the base due to there being more room for the leaching front to spread into. However, if the inlet is positioned too high, the air flow is poor at the base of the heap, and consequently oxygen limitation becomes the most important factor. An explanation for these mechanisms is given. NOMENCLATURE Q heat source term, (W/m3) Rk reaction rate for reaction k, (kg/m3/s) T temperature, (oC) v air velocity vector, (m/s) vL liquid velocity, (scalar and negative) (m/s) Greek αT cumulative copper extracted, (-) ρi density phase i, (kg / m3) μi dynamic viscosity phase i, (kg/m/s) εi volume fraction phase i, (-)