Question

Sulphide ore is converted into pure metal (say $Cu$) by following steps.

Bessemerisation $\to$ Roasting $\to$ Electrolysis

Answer 1

Extraction of Copper:
Copper is mainly extracted from copper pyrites. After the concentration of its ore by froth flotation process, the ore is roasted in a current of air to remove arsenic, antimony and much of sulphur.
The ore is then mixed with a little coke and sand and smelted in a water-jacketed blast furnace. The minor reactions that occurred during roasting continue here. Ferrous oxide combines with sand to form a fusible slag. Cuprous oxide formed combines with ferrous sulphide to give ferrous oxide and cuprous sulphide. This is because iron has more affinity for oxygen than copper.
Molten mass collected from the bottom of furnace contains largely cuprous sulphide and a little ferrous sulphide. This molten mass is known as matte.
The molten matte is finally transferred to Bessemer converter. A blast of sand and air is blown in the converter through tuyeres which are situated a little above the bottom. This causes removal of S and As oxides and ferrous oxide as slag.
Finally, copper may be refined electrolytically (electrolyte; copper sulphate : an anode; impure copper and cathode; pure copper).
So in such extraction, only two steps are followed.