Insights into ferric leaching of low grade metal sulfide-containing ores in an unsaturated ore bed using X-ray computed tomography

Dobson, Katherine J. and Harrison, Sue T.L. and Lin, Qingyang and Bhreasail, Aine Ní and Fagan-Endres, Marijke A. and Neethling, Stephen J. and Lee, Peter D. and Cilliers, Jan J. (2017) Insights into ferric leaching of low grade metal sulfide-containing ores in an unsaturated ore bed using X-ray computed tomography. Minerals, 7 (5). 85. ISSN 2075-163X (https://doi.org/10.3390/min7050085)

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Abstract

The distribution of the metal-bearing mineral grains within a particulate ore prepared for leaching, and the impact of this spatial heterogeneity on overall extraction efficiency is of key importance to a mining industry that must continuously target ever-reducing grades and more complex ore bodies. If accessibility and recovery of the target minerals is to be improved, a more detailed understanding of the behaviour of the system must be developed. We present an in situ analysis using X-ray computed tomography to quantify the rates of volume reduction of sulfide mineral grains in low grade agglomerated copper bearing ores during a miniature laboratory scale column leaching experiment. The data shows the scale of the heterogeneity in the leaching behaviour, with an overall reduction of sulphide mineral grains of 50%, but that this value masks significant mm3 to cm3 scale variability in reduction. On the scale of individual ore fragments, leaching efficiency ranged from 22% to 99%. We use novel quantitative methods to determine the volume fraction of the sulfide that is accessible to the leachate solution.