Sulfate precipitation during oxidative ammonium leach of Cu, Ni, Zn sulfide ores

摘要

In the recovery of copper, nickel or zinc from sulfide ores by leaching with ammonium sulfate solution containing free ammonia in the presence of oxygen to form a leach solution containing dissolved copper, nickel or zinc ammonia sulfate complex, an alkaline metal hydroxide (preferably calcium hydroxide) is introduced into the leaching operation to precipitate the sulfate ion formed and to release ammonia combined therewith as ammonium ion.