Ore Dressing Principles

The process of separating valuable ore from unwanted rocky material (gangue) relies on differences between the physical or chemical properties of the ore and the gangue.

Basis of Gangue Removal

Various techniques are employed for ore dressing, each exploiting specific differences:

• Physical Differences: Methods like magnetic separation, gravity separation (e.g., panning), froth flotation, and electrostatic separation are based on differences in properties such as magnetism, density, wettability, or conductivity.
• Chemical Differences: Processes like leaching use chemical reactions to selectively dissolve the ore or the gangue, enabling separation. For example, in the extraction of gold, leaching with cyanide solution dissolves the gold selectively.

Therefore, the removal of gangue is based on differences in either chemical or physical properties.

Correct Option Identification

Based on the principle that both physical and chemical differences are utilized in ore dressing, the correct option is the one that includes both possibilities.

The correct option is: Chemical or physical