Question

Bauxite ore is concentrated by:
A.Froth Floatation
B.Electromagnetic separation
C.Chemical separation
D.Hydraulic separation

Answer 1

Bauxites are enriched rocks which usually comprise aluminium hydroxides, kaolinite and Ti-oxides which are made due to the intense lateritic weathering of aluminosilicate protoliths. There is a need for largely humid climates for the lateritic weathering and bauxite formation process. For the aluminium metal supply, bauxites are really necessary.

Complete step-by-step answer: The process which is industrial and a means of refining bauxite to extract aluminium is called Bayers process. Alumina is also called aluminium oxide and Bauxite is known to be the most important ore with regards to aluminium as there is approximately forty percent of alumina present in bauxite. The other products present in bauxite are silica, various iron oxide, and titanium dioxide.
There is a need to purify aluminium oxide to extract refined aluminium metal. There might be other aluminium compounds which might be present in the bauxite such as gibbsite and diaspore. The aluminium oxides and hydroxides are both acidic and basic in nature and thus are called amphoteric.
At the end, leaching is done. This is a form of chemical separation. In this the ore is made to come in a powdered form and is treated with a suitable reagent which can dissolve the ore. In this the impurities are left behind thus we can separate them.

Thus the answer is $\left( {{\text{ }}C{\text{ }}} \right)$.

Note: Red mud is a waste product which is left after the digestion by sodium hydroxide of the bauxite ore. This is enriched with calcium and sodium hydroxide and this makes it very caustic and a significant source of pollution. It has been tried to be used in various other areas such as production of ceramic with it.