Pb–Zn mine tailings reprocessing using centrifugal dense media separation

• Published in: Minerals engineering Vol. 131; pp. 28 - 37
• Main Authors: Khalil, A., Argane, R., Benzaazoua, M., Bouzahzah, H., Taha, Y., Hakkou, R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.01.2019
• Subjects: Centrifugal separation; Dense medium separation; Separation efficiency; Toxicity characteristic leaching procedure; Toxicity characteristic leaching procedure; Separation efficiency; Dense medium separation; Centrifugal separation
• ISSN: 0892-6875; 1872-9444
• DOI: 10.1016/j.mineng.2018.10.023

•Laboratory centrifugal dense media separation was tested on Pb-Zn mine tailings.•High metal recoveries and upgrade ratios were obtained.•Centrifugal dense media separation can serve as a depollution technique for base-metal mine tailings.•The separation efficiency was assessed by the Toxicity Characteristic Leaching Procedure environmental test. 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.