Question

What is matte and how it is formed during extraction of copper

Answer 1

Copper is obtained from copper pyrites (CuFeS2) by following steps:
(a) Concentration: The ore is crushed and agitated with a mixture of pine oil and water.Frothing takes place and the ore particles are carried with the foam to the top from where they are skimmed off while the gangue particles settle at the bottom.
(b) Roasting: The concentrated ore is heated in limited supply of air.

(c) Smelting: The roasted ore is mixed with sand and powdered coke a nd hot blast of air is passed through it in a blast furnance.

The mixture of copper sulphide and some iron sulphide left is known as matte which is collected from the lower hole of the furnance.
(d) Bessemerization: The matte is introduced in the Bessemer converted and heated by blowing hot air blast of air and sand.

The copper obtained is 99% pure