Primary Copper Smelting
U. S. ore. Fourteen domestic mines accounted for more than 95 percent of the megagrams (Mg) ( millon tons) of ore produced in 1991. Copper is produced in the U. S. primarily by pyrometallurgical smelting methods. Pyrometallurgical techniques use heat to separate copper from copper sulfide ore concentrates. Process steps include mining, concentration, roasting, smelting, converting, and ...