Froth floatation process is used for the concentration of

Froth flotation process is used for the concentration of:

Froth floatation is based upon

Name the reagent that is used in leaching of gold.

Haematite ore is concentrated by

The correct statements regarding the froth floatation method in metallurgy are:
$I$. Used for the purification of sulphide ores
$II$. Used for the roasting of sulphide ores
$III$. It is based on the relative densities of gangue and ore particles
$IV$. It is based on the difference in the wetting properties of gangue and ore particles in frothing agent and water