Advancements in the approach to research and design of heap bioleaching processes
As higher grade resources are becoming depleted, the attention is shifting to the treatment of lower-grade , more complex and refractory ores, many of which can only be economically treated by heap leaching. The approach adopted for the treatment of primary copper ore deposits containing chalcopyrite has been to promote the preservation of heat within the heap, thereby overcoming the passivation of chalcopyrite. Currently the engineering design of heap leach plants relies heavily on empirical scale-up factors, which introduce uncertainty and risk into the design of the process. The treatment of low-grade chalcopyrite introduces a further degree of complexity to the process in terms of the requirement for microbial growth over a range of temperatures, optimization of parameters such as irrigation and aeration rates to maximize heat retention, while at the same time maximising copper recovery and minimising gangue reactions and precipitate formation. These issues has led Mintek to develop operational strategies, control systems and specially designed columns to simulate the natural dynamic temperature behaviour in actual heaps. In this paper approaches to address and overcome some of these challenges will be discussed and illustrated with examples. These include ( i) the use of the SmartColumn? for simulation of natural temperature profile development in heap leach processes (ii) microbial succession and correlation of microbial types with changes in the chemical and physical profiles in the heap as well as inoculation strategies; (iii) the development of models to predict the impact of gangue chemistry of the ore on acid consumption, especially important when operating at high temperatures; (iv) geomechanical testing to assist with the selection of optimal operation conditions, including maximum lift height, maximum heap height, irrigation and aeration and ( v) the development of HeapStar?, an administration and guidance system to keep track of the irrigation and drainage liquor allocations, and varying irrigation and aeration requirements over a number of heaps at different stages of their life cycles.
heap bioleaching chalcopyrite control strategies
Mariekie Gericke AN Seyedbagheri John Neale Petrus van Staden
Biotechnology Division, Mintek Private Bag X3015, 2125, Randburg, South Africa
国际会议
The 19th International Biohydrometallurgy Symposium(第19届国际生物湿法冶金大会 IBS2011)
长沙
英文
698-705
2011-09-18(万方平台首次上网日期,不代表论文的发表时间)