Question

Which of the following statements is incorrect about the extractive metallurgy of copper?

• A. The main impurity in blister copper is iron.
• B. Most of the impurities of iron sulphide are removed as fusible slag during roasting.
• C. Copper pyrite is concentrated by froth floatation process.
• D. The copper obtained from Bessemer converter is called as blister copper.

Answer 1

Answer: (B)

Most of the impurities of iron sulphide are removed as fusible slag during roasting.

The main impurity in blister copper is iron.

Copper pyrite is concentrated by froth floatation process.

The copper obtained from Bessemer converter is called as blister copper.

However, the roasting and smelting processes involve the following reactions:

Roasting step:
$2CuFe{S}_2+4O_2\to C{u}_{2}S+2FeO+3S{O}_2$

Smelting step:
$FeO+Si{O}_2\to FeSi{O}_3\left(slag\right)$

So, most of the impurity of iron sulphide is removed as slag during smelting.

Hence, the statement in option B is incorrect.