$A$ process used for the concentration of ore is

Which soluble substances are obtained when bauxite is treated with a solution of $NaOH$ at a temperature of $473 - 523 \ K$ and a pressure of $35 - 36 \ bar$?

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

Which oil is used in the froth flotation process for the concentration of ores?

Which of the following metals can be extracted through alkali leaching technique?

In the process of extracting alumina from bauxite,bauxite is concentrated by $......$.