The ore of which metal is concentrated by leaching?

Magnetic separation method is applicable for the concentration of which of the following ores?

Reagent used in Bayer's process of concentration of bauxite ore is:

In the $Hoopes$ process,what is the bauxite ore treated with?

While extracting an element from its ore,the ore is ground and leached with dilute $KCN$ solution to form the soluble product potassium argentocyanide. The element is

The role of depressants in the Froth Flotation method is to $.....$.