What is the composition of 'Copper matte'?

Copper Matte is the mixture of copper sulphide (Cu₂S) and some iron sulphide (FeS). Matte is the phase where copper is extracted prior to the final reduction. The roasted ore is mixed with coke and silica (sand) SiO₂ and is introduced into a blast furnace. The hot air is blasted and FeO is converted into ferrous silicate (FeSiO₃). FeSiO₃ (slag) floats over the molten matte of copper.