Selective Sulfidation for Rare Earth Element Separation

Liquid Copper and Iron Production from Chalcopyrite, in the Absence of Oxygen

“…To process in the sulfide regime, i.e., in absence of oxygen-containing species, the oxide, sulfate, and hydrated compounds must be converted to sulfides. Elimination of oxygen from the concentrate feedstock prior to mixing with the supporting electrolyte is necessary to avoid oxysulfide formation and degradation of the electrolyte [51]. Sulfidation of these copper compounds is exothermic, indicating that the reaction may be conducted with little to no external heating.…”

“…Sulfidation of these copper compounds is exothermic, indicating that the reaction may be conducted with little to no external heating. Depending on the oxide content of the feed (and therefore heat generation), sulfidation may provide a means to preheat and melt feedstocks prior to electrolysis [52].…”

“…While impurities are reportedly lacking from North American ores, they are of wide interest and in urgent need of improved processing in South America, especially the hazardous Group 15 elements. Stinn et al [52] demonstrate the applicability of sulfidation to decrease arsenic, antimony and selenium in enargite-rich and tennantite ore by 72-99%, with low costs and environmental impacts. Determining the conditions to treat a complex feedstock requires careful thermodynamic and mineralogical analysis of the initial phase, morphology and concentration of the impurities present, in addition to experimental testing.…”