Question

Explain the process of obtaining “blister copper” from “copper matte” with equations.

Answer 1

Blister copper is a metallic copper which has a black blistered surface, as we already know it is the product formed by converting copper mate and the product which is formed is 98.5 percent pure, also called Bessemer copper.

Complete step by step answer:
Let us first understand what copper matte is,
- In simple words copper mate is a combination of copper sulphide and a small amount of iron sulphide. Matte is nothing but it is the subsequent to the final reduction process which involves converting it to crude copper.
Let us understand what Bessemerization is.
- In this process Copper metal is extracted from molten matte through bessemerization process. The matte is introduced into the Bessemer converter. – - Then, the air is blown through the molten matte. Blast of air converts $C{u_2}S$ partially into $C{u_2}O$ which reacts with remaining $C{u_2}S$ to give molten copper.
$2C{u_2}S + 3{O_2} \to 2C{u_2}O + 2S{O_2}$
- The copper which is obtained is called "Blister copper" because, as it solidifies $S{O_2}$ which is hidden in it escapes out producing blisters on its surface.
$2C{u_2}O + C{u_2}S \to 6Cu + S{O_2}$
- Blister copper is 99% pure, but it still contains a small amount of impurities like iron, As, Zn and Au etc. These impurities must be removed because it affects the electrical and mechanical properties of copper.
Let us understand in brief how copper can be refined.
- Blister copper is refined by electrolysis.
- Blister copper is used as anode and pure copper is used as cathode.
- In order to remove the deposited copper from the cathode, it is coated with graphite.
- The electrolyte is copper sulphate $CuS{O_4}$ mixed with a little amount of ${H_2}S{O_4}$ to increase the electrical conductivity.
- During electrolysis, pure copper gets collected on the cathode and impurities which are soluble get collected at the bottom of the cell which is also known as anode mud or sludge.

Note: You should know that most copper produced today is utilized to conduct electricity, in cooking utensils, heat sinks and heat exchangers. Large amounts are also used to make alloys.