Copper matte contains Cu₂S and FeS. Copper matte is put in a silica-lined converter to remove the remaining FeO and FeS present in the matte as slag (FeSiO₃). Also, some silica is added to the silica-lined converter. Then, a hot air blast is blown. As a result, the remaining FeS and FeO are converted to iron silicate (FeSiO₃) and Cu₂S is converted into metallic copper.

2FeS + 3O₂ → 2FeO + 2SO₂

FeO + SiO₂ → FeSiO₃

2Cu₂S + 3O₂ → 2Cu₂O + 2SO₂

2Cu₂O + Cu₂S → 6Cu + SO₂