611 RACER disrupts this chain by providing ambient electrochemical leaching on-site or in nearby processing facilities. The process reduces copper minerals directly into a pregnant leach solution, which is then refined via solvent extraction and electrowinning (SX/EW) to produce high-purity copper cathode without any smelting step, and without costly, potentially transcontinental concentrate transport. RACER (Figure 1) enables the rapid extraction of copper metal from chalcopyrite using vanadium (II) as an electrochemical reducing agent. The reaction between vanadium (II) and chalcopyrite leads to complete copper extraction in under 60 minutes. The copper reduction reaction yields three phases. The solid phase contains elemental copper, unreacted metal co-products, and unreacted minerals, including pyrite and silicates. The liquid effluent contains oxidized vanadium (III) ions and ferrous reduced from ferric in chalcopyrite. The iron is recovered as iron sulfate via precipitation. The reaction also evolves gaseous hydrogen sulfide, a toxic but common byproduct in mining and oil and gas, which is fully recovered and converted to valuable co-products like elemental sulfur via the commonly deployed Claus process. The vanadium (III) in the liquid phase is then reduced back to vanadium(II) using our proprietary electrolyzer for continued copper extraction. The copper in the post-reaction solids is leached into a PLS, separated from iron via solvent exchange, and finally electrowon to produce metallic copper. Figure 1 – Simplified process flow diagram of Still Bright’s RACER. Copper cathode is produced from copper feed, which can be any copper-containing sulfide concentrate, including finished copper concentrate and rougher concentrate. Iron is captured as ferrous sulfate, sulfur is captured via the Claus process as elemental sulfur or sulfuric acid, and other metal co-products can be captured from metal-enriched residual solids via conventional processing methods.
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