Bugs tease tellurium out of mine tailings—first results

colonies of an iron-oxidizing bacterium isolated from the tailings, growing on Fe(II) amended agar.
Colonies of an iron-oxidizing bacterium isolated from the tailings, growing on Fe(II) amended agar.

CMI researchers at Idaho National Laboratory conducted the research for this highlight

Achievement
The activity of iron- and sulfur-oxidizing microorganisms can enhance tellurium extraction from mine tailings. 

Significance and impact
Te is critical for CdTe-based photovoltaics. Currently almost all Te is produced from copper anode slimes, and U.S. production is limited to one facility. Recovery from domestic mine wastes could provide more Te than total current imports, and biorecovery from a waste product could have significant environmental benefits.

Details and next steps

  • Te was solubilized from gold tailings by constructed consortia of iron and sulfur oxidizing microorganisms, likely enhanced by indigenous microbes.
  • Different conditions will be tested to improve recovery and extend the approach to other tailings samples.
     
Tellurium recovery after two weeks of leaching as a percentage of Te content of the original tailings (assayed at 7.8 ppm Te). Tailings were leached in a medium (“9K”) provided with Fe(II) and elemental S with combinations of three organisms as shown.
Tellurium recovery after two weeks of leaching as a percentage of Te content of the original tailings (assayed at 7.8 ppm Te). Tailings were leached in a medium (“9K”) provided with Fe(II) and elemental S with combinations of three organisms as shown.