Table of Contents Experimentation with chalcopyrite concentrate in dilute hydrochloric acid, under reflux conditions (in Pyrex flasks) and with an inert purge gas, revealed substantial amounts of H2S production and iron solubilization, with negligible copper solubilization, after 2½-4 days. Under comparable condition the extent of reaction with dilute sulfuric, acetic and phosphoric acids was markedly … Continue reading Hydrochloric Acid Copper Leaching