International Journal of Mineral Processing, 31 ( 1991 ) 247-264 247 Elsevier Science Publishers B.V., Amsterdam A model for the bacterial leaching of copper sulfide ores in pilot-scale columns Heinz J. Neuburg, Jorge A. Castillo, Miguel N. Herrera, Jacques V. Wiertz, Tom~s Vargas and Ricardo Badilla-Ohlbaum t Department of Chemical Engineering, Faculty of Physical and Mathematical Sciences, University of Chile, Casilla 2777, Santiago, Chile (Received February 5, 1990; accepted after revision October 19, 1990) ABSTRACT Neuburg, H.J., Castillo, J.A., Herrera, M.N., Wiertz, J.V., Vargas, T. and Badilla-Ohlbaum, R., 1991. A model for the bacterial leaching of copper sulfide ores in pilot-scale columns. Int. J. Miner. Pro- cess., 31:247-264. The kinetics of the bioleaching of a low-grade copper ore was studied in a pilot-scale leaching col- umn over a period of 360 days using an open-circuit leaching regime with a fresh sulfuric acid solution at pH = 2 at the inlet of the column. The effluent solutions were periodically analyzed for Cu, total Fe and Fe(II) concentrations as well as Eh and pH values. Bacterial population was measured both in the solution (free cells) and at the surface of the ore particles. Bacterial growth parameters and the true kinetic constant for the dissolution of the sulfide minerals present in the ore were determined in independent experiments. A generalized phenomenological model for the bioleaching of sulfide ores is presented, for which practically all the required parameters can be independently measured. The model is capable of reproducing well measured values of the process variables, and the results are extended to the simulation of the process under different operating conditions. INTRODUCTION Hydrometallurgical processes based on bacterial leaching/solvent extrac- tion/electrowinning are increasingly applied worldwide, particularly for the recovery of copper from low-grade sulfide ores which are otherwise wasted. Depending upon the characteristics of the deposit and the ore, the technology is applied in different ways: heap leaching, in situ leaching and in place min- eral processing operations (e.g., Murr, 1980 ). This technology is also applied to the recovery of other metals such as gold (by bacterial oxidation of refrac- tory ores) and uranium. Process design and operation of these complex me- tallurgical operations can be better approached with the aid of mathematical For all correspondence. 0301-7516/91/$03.50 © 1991- Elsevier Science Publishers B.V.