Proposed processing of zinc ferrite residue from zinc smelting yields separate streams for the critical materials Ga, In, and Ge while also producing revenue from increased Zn recovery.

A new method to recover In, Ga, and Ge from zinc smelting

Proposed processing of zinc ferrite residue from zinc smelting yields separate streams for the critical materials Ga, In, and Ge while also producing revenue from increased Zn recovery.
Proposed processing of zinc ferrite residue from zinc smelting yields separate streams for the critical materials Ga, In, and Ge while also producing revenue from increased Zn recovery.

CMI researchers at Colorado School of Mines conducted the research for this highlight

Achievement 
A novel approach for recovering Ga, Ge, and In from zinc plant residues has been developed.

Significance and impact

  • Opens up a large potential domestic source of critical materials needed for photovoltaics, electronics, and flat-panel displays. 
  • US import reliance for Ga and In is 100%, but the US has major Zn mining and smelting that can supply domestic demand.

Details and next steps

  • The key advance is decomposition of zinc ferrite by controlled hydrogen reduction to zinc oxide and magnetite. It eases the leachability of target elements (Ga, Ge and In). 
  • Zinc recovery up to 96% has been demonstrated at lab scale. Added Zn value greatly boosts overall economic benefit. A significant increase in leaching kinetics of Ga, Ge and In has been observed in latest experiments.
  • Leaching conditions are being optimized and selective extraction methods for the leachates are being developed.