Bioleaching model of a copper-sulfide ore bed in heap and dump configurations

Abstract

A two-dimensional (2-D) model for a heap or dump bioleaching of a copper ore containing mainly chalcocite and pyrite has been developed. The rate of the mineral sulfide dissolution was related to the rate of oxidation by bacteria attached onto the ore surface. The latter was calculated using the model of Michaelis-Menten, where both temperature and dissolved oxygen in the leach solution were taken into account by the kinetic equation. Oxygen transport through the ore bed was associated with natural air convection originating from the decrease in gas density inside the ore bed, which was attributable not only to heating, but also to humidification and decrease in the oxygen concentration. The model was used to estimate air-velocity fields and profiles of temperature and oxygen concentrations as well as mineral conversions during the bioleaching operation for ore beds with different pyrite contents, bacterial populations, widths, heights, and permeabilities. The model provides a useful tool for the design, improvement, and optimization of industrial operating conditions.

Mathematical model for coupled reactive flow and solute transport during heap bioleaching of copper sulfide

“…Similar to the solution flow, the momentum equations of air flow are described by the N-S equations, with a reduced air space for flow based on the porosity and a resistivity to the flow due to the porous media. The steady state flow is described by the equation of continuity and the steady state N-S equations given by [11]:…”

“…To simulate the transport of solutes through the flowing channels and the stagnant pores of an unsaturated heap, three models (mixed side-pore diffusion and profile side-pore diffusion with uniform or distributed pore lengths) are derived by BOUFFARD and DIXON [10]. CASAS et al [11] used the model of Michaelis-Menten to calculate the oxidation rate by bacteria attached onto the ore surface, and assumed that a constant number of bacteria homogeneously distributed through the bed. DIXON [12] carried out an analysis of heat conservation during copper sulphide heap leaching, and postulated a new mode of heap behaviour called evaporative autocatalysis.…”

A 3D coupled model of turbulent forced convection and diffusion for heat and mass transfer in a bioleaching process

“…The numerical simulations have been applied to bioleaching piles by finite difference methods [4][5][6][7], finite element methods [8,9] and finite volume methods [8,10]. A mathematical model for the self-heating in piled material introduced by Sidhu et al [11] was modified [12][13][14] to include the oxidation kinetic being catalyzed by thermophilic microorganisms in the bioleaching pile.…”

A comprehensive model for copper sulphide heap leaching

“…These models have involved studies of fluid flow (Bouffard and Dixon, 2001;Pantelis et al, 2002), chemical dissolution rates (Casas et al, 1998;Dixon and Hendrix, 1993;Madsen and Wadsworth, 1981;Paul et al, 1992aPaul et al, , 1992b, and heat/temperature balances (Cathles and Apps, 1975;Dixon, 2000). Watling (2006) and Dixon (2003) provide recent reviews of the bioleach process and the status of modelling efforts.…”