$A$ substance which reacts with gangue to form fusible material is called:

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:

Which one of the following is true?

Which of the following ores can be concentrated by the froth flotation method?

Cassiterite is concentrated by

The beneficiation of the sulphide ores is usually done by