Which method is used for the concentration of iron pyrites ore?

Sulphide ores of metals are usually concentrated by froth floatation process. Which one of the following sulphide ores offers an exception and is concentrated by chemical leaching?

For the purification of alumina,the modern processes most useful when $(i)$ the impurity present is a lot of iron oxides and $(ii)$ the impurity present is a lot of silica,are:

Bauxite,an ore of aluminium,is purified by which process?

Which substance is used as a froth stabilizer in the froth flotation process?

The substance which is mixed with the ore for the removal of impurities is termed as