Acid bake–leach process for the treatment of arsenopyrite, tennantite, and tetrahedrite

The preliminary results of the application of sulfuric acid baking followed by water leaching for the treatment of arsenopyrite (FeAsS), tennantite (Cu12As4S13), and tetrahedrite (Cu12Sb4S13) have been reported. Baking of pulverized minerals (P100 = 106 μm) at 200 °C with a sulfuric acid/mineral powder ratio of 5/3 (g/g) in a muffle furnace for 7 h resulted in the transformation of the mentioned minerals to water soluble compounds. Arsenopyrite transformed into FeSO4 and As2O3, both of which are highly soluble in water. Tennantite transformed into CuSO4 and As2O3 whereas tetrahedrite transformed into CuSO4 and Sb2O3. While CuSO4 and As2O3 completely dissolved in water, Sb2O3 did not dissolve, reporting to the leach residue. More than 63% of iron and arsenic from arsenopyrite, and more than 86% of copper from tennantite and tetrahedrite were extracted into water.