Recovery of rhenium from molybdenum and copper concentrates during the Looping Sulfide Oxidation process

• Rhenium behavior during Looping Sulfide Oxidation has been modeled in FactSage®.
• ReS2 is fully oxidized to Re2O7 during Looping Sulfide Oxidation of CuFeS2.
• Re2O7 is reduced to Re at elevated temperature under sufficient S2 partial pressure.
• Conditions for rhenium recovery during Looping Sulfide Oxidation are identified.
• Improved Re recovery is expected due to higher Re2O7 concentrations in the off gas.

Rhenium is recovered during pyrometallurgical processing of molybdenum sulfide and copper sulfide ores; the traditional technology involves removing rhenium(VII) oxide, Re2O7, from the sulfurous gas phase generated during multiple hearth roasting (in molybdenum processing) and smelting (in copper processing). A new technology platform called Looping Sulfide Oxidation (LSO) has been proposed to produce molybdenum and copper using alternative process chemistries. A detailed thermodynamic study of the reaction conditions used in LSO process indicates that rhenium recovery is possible at higher rates than currently realized in the industry. Conditions at which Re2O7 is reduced to rhenium metal by S2 have been identified and key process conditions are outlined to maximize performance of the LSO scheme and rhenium recovery.