Minerals Engineering, Vol.131, 28-37, 2019
Pb-Zn mine tailings reprocessing using centrifugal dense media separation
The management of mine tailings has become a worldwide environmental concern. In fact, with the more restrictive environmental regulations, there is a pressing need to develop efficient and clean techniques to properly manage these industrial wastes. This work investigates the use of centrifugal Dense Medium Separation (DMS) as a depollution process of Pb-Zn tailings in order to reduce their residual metal content. The obtained results showed that DMS technique allowed high recovery of cerussite (PbCO3) and smithsonite (ZnCO3) present in the studied tailings. Consequently, it has successfully depolluted the studied mine tailings. The effectiveness of DMS was accessed both by the Separation Efficiency (SE) factor and the Toxicity Characteristic Leaching Procedure (TCLP) environmental test. The recoveries of Zn and Pb to the heavy fraction are 88.83% and 91.66% respectively. The observed concentrations of contaminants in TCLP leachates from the light fraction, consisted mainly of dolomite and silicates (quartz, orthoclase, albite and chlorite), are below the limits authorized by the US-EPA regulation for non-hazardous wastes. The DMS allowed a reduction of the concentration of leached Pb by more than 95% in both tailings, and a reduction of the concentration of leached Zn by more than 78% in the case of Bb tailings.
Keywords:Dense medium separation;Centrifugal separation;Separation efficiency;Toxicity characteristic leaching procedure