Question

Which of the following process is not a physical process of separation?

• A. Levigation
• B. Magnetic separation
• C. Leaching
• D. Froth fioatation

Answer 1

The correct option is C Leaching

Leaching involves the treatment of the ore with a suitable reagent to make it soluble while impurity remains insoluble. The ore is recovered from the solution by suitable chemical method.

For example Bayer's process:

Bauxite ore contains impurities like $F{e}_2{O}_3$, $Ti{O}_2$ and $Si{O}_2$. So, when it dissolve in aq. NaOH/pressure + 150°C T, bauxite dissolves but others donot dissolve.

$A{l}_2{O}_3+2NaOH\to 2NaAl{O}_2+H_{2}O$

$NaAl{O}_2+2H_{2}O\to Al(OH{)}_3+NaOH$