Explain the role of 1. Limestone in extraction of iron. 2. Cresol and aniline in froth floatation process.

Question

Explain the role of

1. Limestone in extraction of iron.
2. Cresol and aniline in froth floatation process.
3. SiO₂ in extraction of copper from copper matte.

Answer 1

1. Umestone on heating decomposed in CaO and CO₂. CaO combines with impurity (SiO₃) to give slag and CO₂ combines with C to form CO (reducing agent for reduction of FeO).

2. Cresol and aniline behave as froth stabilizer i.e. stabilises froth in thick scum.

3. SiO₂ combines with FeO present in copper matte

• FeS + O₂ → FeO + SO₂
• FeO + SiO₂ → FeSiO₃

i.e. impurity of FeO can be eliminated as slag.