Removal of the unwanted materials (e.g., sand, clays, etc.) from the ore is known as concentration, dressing or benefaction. Before proceeding for concentration, ores are graded and crushed to reasonable size. Concentration of ores involves several steps and selection of these steps depends upon the differences in physical properties of the compound of the metal present and that of the gangue. The type of the metal, the available facilities and the environmental factors are also taken into consideration. Some of the important procedures for concentration of ore are:

(i) Hydraulic washing

(ii) Magnetic separat

(iii)Froth-floatation process

(iv) Leaching

Which of the following is not a collector used in the froth floatation process?

Aniline

The correct answer is option 4. Aniline.

In the froth flotation process, collectors are chemicals that are used to selectively bind to the surface of target minerals, making them hydrophobic and enabling their separation from the rest of the ore material in a flotation cell.

Potassium ethyl xanthates and Ethyl xanthate are both common collectors used in froth flotation. They are xanthate compounds that help in the flotation of sulfide minerals.

Pine oil is also a commonly used collector in froth flotation. It is often used in the flotation of non-sulfide minerals.

However, aniline is not typically used as a collector in the froth flotation process. Aniline is an organic compound, but it is not commonly employed as a collector due to its properties and effectiveness in mineral flotation.

So, the correct answer is option (4) Aniline.