Gold Dissolution from Ore with Iodide-Oxidising Bacteria

Sci Rep. 2019 Mar 12;9(1):4178. doi: 10.1038/s41598-019-41004-8.

Abstract

Gold leaching from ore using iodide-iodine mixtures is an alternative to gold cyanidation. This study evaluated the ability of iodide-oxidising bacteria to solubilise gold from ore that was mainly composed of gold, pyrite, galena, and chalcopyrite. Eight bacterial strains were successfully isolated from brine. Those strains were incubated in a liquid culture medium containing ore with a gold content of 0.26 wt.% and pulp density of 3.3 w/v% to evaluate their abilities to mediate the dissolution of gold. The gold was solubilised completely within 30 days of incubation in the iodine-iodide lixiviant solution generated by three bacterial strains. One strain, in particular, completed the dissolution of gold within 5 days of incubation and was identified as a member of the genus Roseovarius. Thus, the possibility of bacterial gold leaching using iodide-oxidising bacteria was successfully demonstrated. Bioleaching gold with iodide would likely be more environmentally sustainable than traditional cyanide leaching. Further research is required to evaluate the techno-economic feasibility of this approach.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria / metabolism*
  • Colony Count, Microbial
  • Gold / chemistry*
  • Hydrogen-Ion Concentration
  • Iodides / metabolism*
  • Mining*
  • Oxidation-Reduction
  • Solubility
  • Time Factors

Substances

  • Iodides
  • Gold