a) Metal sulphides get wetted mainly with oil as they are hydrophobic
Answers
Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic. it is mainly used for treatment of sulphide ores.
In some cases for example, sulphides ores of copper, zinc and lead concentration is brought by this method. In this method advantage is taken of the referential wetting of the ore by an oil. The finely ground ore is taken in a tank containing water and 1% of pine oil or terpentine oil.
A strong current of air is blown through the suspension, producing a heavy froth or foam on the surface.The metal sulphide is wetted by the oil but the gangues is not and the sulphide-oil mixture is carried to the surface by films of oil. The froth is skimmed off, the gangue settles down on the bottom or remains underneath the froth. Hence, it is applicable for ZnS.