Copper Extraction from Chalcopyrite in Various Hydrometallurgical Systems

Copper sulfide concentrate leaching, particularly chalcopyrite or other primary copper sulfides, has been investigated as an alternative to the conventional smelting. The grand challenge for copper industry is to improve copper extraction from the primary sulfides such as chalcopyrite. A newly developed method using activated carbon showed almost 99% copper extraction from a chalcopyrite concentrate containing 85% chalcopyrite and 8% pyrite. The system used sulfuric acid and ferric ion as a stock solution with activated carbon as an additive. In the absence of the activated carbon, only 19.2% copper extraction was observed for 96 hours at 65℃. With 10 g/L activated carbon increased the copper extraction up to 98 % for 48 hours at 65℃ in 10 g/L H2SO4. The activation energy of the H2SO4-activated carbon leaching system was 127.47 kJ/mol from the 25-65℃ temperature range, indicating the reaction is controlled by the chemical reaction. The system enhanced the copper extraction without surface passivation under the conditions used because the solution potential has been maintained lower than 640 mV vs. SHE. This leaching system is also compatible with the current solvent extraction and electrowinning process without any modification.