Other Metals Are Most Commonly Obtained from Metal Sulfides

OTHER METALS ARE MOST COMMONLY OBTAINED FROM METAL SULFIDES 

Metal sulfide Oxygen Metal Sulfur dioxide 

The isolation of copper from its most common ore, chalcopyrite, requires several additional steps because of the presence of iron. First the chalcopyrite is roasted in the presence of oxygen  

The copper sulfide and iron oxide from this reaction are then mixed with limestone, CaC03, and sand, Si02, in a blast furnace, where CuS is converted to Cu2S. The limestone and sand form molten slag, CaSi03, in which the iron oxide dissolves. The copper sulfide melts and sinks to the bottom of the furnace. The less-dense iron-containing slag floats above the molten copper sulfide and is drained off. The isolated copper sulfide is then roasted to copper metal  

Roasting metal sulfides requires a fair amount of energy. Furthermore, sulfur dioxide is a toxic gas that contributes to acid rain, and so its emission must be minimized. Most companies comply with EPA emissions standards by converting the sulfur dioxide to marketable sulfuric acid, H2S04. 

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