The Development of a Diagnostic Leaching Method for South African Low Grade Uranium Ores
Gold deposits in South Africa are invariably associated with uranium bearing minerals. Although it is low grade uranium by international standards, averaging around 0.3 kg U3O8 per ton of ore, recovery of uranium as a by-product improves the overall economics of gold extraction.Moreover, the current high uranium prices as well as increased demand due to renewed interest in nuclear power provide significant incentives for dedicated uranium production. An understanding of the uranium leaching response to changes in operating conditions is an important first step towards optimisation of uranium recoveries. In South African acid leaching plants, uranium dissolutions higher than 90% are difficult to achieve, and the chemical origin of this limit is not clear.To study leaching behaviour, an important consideration is the mineralogical characteristics of the ores. Typically, a diagnostic leaching approach can be followed. In this paper, a mineralogy-leachability explanation is presented to rationalise the difficulty in exceeding 90% dissolution from low grade uranium ores on the basis of a simple diagnostic leaching method. It was found that brannerite was the main reason for the existence of a dissolution limit in Witwatersrand ore and that chemical liberation was more effective to increase end dissolution compared to physical liberation.The findings from these investigations will form guidelines for developing economically viable flow sheets for improved uranium recovery, at least in a South African (Witwatersrand) context.
Diagnostic leaching Uranium
M.J. Lottering L. Lorenzen
Department of Process Engineering, University of Stellenbosch, South Africa
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
2899-2904
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）