Question

Earthly particles in an ore are removed from heavier metal ore using water in:

• A. levigation
• B. hydraulic washing
• C. leaching
• D. gravity separation

Answer 1

Answer: (A), (B), (D)

The correct options are
A levigation
B hydraulic washing
D gravity separation

Gravity separation/levigation / hydraulic washing: All these methods are based on the difference in densities of the metallic ore and gangue particles. Powdered ore is treated with a stream of running water when the lighter gangue particles are washed away and heavier ore particles are left behind.

In leaching, a suitable reagent (not water) only dissolves the ore leaving behind the impurities. Thus, leaching is a chemical method of separation / concentration of the ore from impurities.

Option A,B and D are correct.