Roasting
The heating of a sulfide ore strongly in a plentiful supply of air to convert it into the oxide.
Formula / equation
2MS + 3O₂ → 2MO + 2SO₂
Unit
°C
In depth
Roasting differs from calcination in requiring abundant oxygen and involving genuine oxidation rather than simple thermal breakdown. The sulfur dioxide produced was historically a major source of acid rain and is now captured and converted into sulfuric acid.
Examples in the real world
2ZnS + 3O₂ → 2ZnO + 2SO₂ in zinc extraction; roasting copper pyrites before smelting.