Copper Production

The most abundant copper ore is chalcopyrite, CuFeS2. There are two ways in which copper may be extracted from its ore:
· Pyrometallurgical method
· Hydrometallurgical method

In Pyrometallurgy, copper ores are roasted with air to create iron oxide, and leave behind copper sulfide.

2 CuFeS2(s) + 3 O2(g) ----> 2 CuS(s) + 2 FeO(s) + 2 SO2(g)

Ground limestone, sand, and fresh concentrated ore are added to the copper sulfide and iron oxide, and heated at 1100°C in a blast furnace (smelting). In the furnace, calcium silicate forms, dissolving the iron oxide.

CaSiO3(l) + FeO(s) + SiO2(s) ----> 2 (Fe,Ca)SiO3(l) (slag)

Concurrently, excess sulfur reduces copper(II) sulfide to copper sulfide, Cu2S, which melts and sinks to the bottom of the furnace (floatation). Due to the lower density of the slag, it is draw off, separating iron from copper.

The bottom layer of Cu2S, the matte, is removed and put into a converter. There it is blown with air, oxidising the sulfid...