Ores which are concentrated by froth flotation process are :
(i) Copper pyrite, `CuFeS_(2)` ltbr. (ii) Siver glance or argentite, `Ag_(2)S`
(iii) Zinc blemde, `ZnS`
Depressant are compounds which are used to prevent certain type of particles form forming the froth with the bubbles.
