Removal of metals from lead-zinc mine tailings using bioleaching and followed by sulfide precipitation

- Bioleaching combined sulfide precipitation is a feasible method to remove metals.
- FTIR and XRD confirmed the composition of tailing was changed during bioleaching.
- Sulfide precipitation can remove metals in bioleaching solution.
- Kinetic is controlled by shrinking core model after some time had elapsed.

Mine tailings often contain significant amounts of metals and sulfide, many traditional operations used to minerals was not as good as those currently available. This study investigated metals removal from lead-zinc mine tailings using bioleaching and followed by sulfide precipitation. Metals were dissolved from the tailings by the bacteria in a bioleaching reactor. During a 10% pulp density bioleaching experiment, approximately 0.82% Pb, 97.38% Zn, and 71.37% Fe were extracted after 50 days. With the pulp density of 10% and 20%, the dissolution of metals followed shrinking core kinetic model. Metals (Pb, Zn, and Fe) present in the pregnant bioleaching leachate. Metals were next precipitated as a sulfide phase using sodium sulfide (Na2S). Metal precipitations were selectively and quantitatively produced from the bioleaching leachate by adding Na2S. More than 99% of the zinc and 75% of the iron was precipitated using 25 g/L Na2S in the bioleaching leachate. The results in the study were to provide useful information for recovering or removing metals from lead-zinc mine tailings.