Bio reactor simulation and modeling for a gold bio leaching process

Bio leaching is becoming increasingly used for the extraction of gold from refractory gold ore. It is established that in gold bio leaching two kinds of mechanism are involved namely indirect bio leaching and direct bio leach ing. The reaction schemes involved in the different mechanisms and kinetic rate expressions for different reactions have been reported in the literatu re. In the present paper an attempt has been made to develop an approach for si mulation of a gold bio reactor leach circuit. For this purpose a mathematic al model for bio leaching has been developed for process design of a gold b io reactor circuit. The salient features of the model are parameter estimat ion from experimental data and then scaling up the process for pilot size a nd industrial size bio reactor operation in continuous mode. Bio reactors c an be simulated for various combinations of series-parallel modes of operat ion. Experimental data of the laboratory scale bio reactor collected for di fferent pulp densities and residence times have been simulated for paramete r estimation. Experimental data of pilot size bio reactors, collected from the literature, have been used for vetting of the parameters estimated earl ier. Analysis of the simulation results indicates the extent of conversion taking place due to indirect and direct mechanisms. The performance of the simulation model developed based on literature information has been confirm ed by some experimental data collected as well as by literature data. (C) 2 001 Elsevier Science Ltd. All rights reserved.