Question

The process of ore dressing is carried out to:
(A). Remove the siliceous materials.
(B). Add flux to the mineral.
(C). Convert the ore not oxide.
(D). Remove the poisonous impurities.

Answer 1

Hint: Ores that are obtained from the earth's crust are never pure . They are usually associated with earthly and siliceous impurities ( in addition to the impurities of other minerals ) called gangue or matrix . These impurities have to be removed from the ore before the extraction of the metal is actually done .

Complete answer:
Ores that are the minerals from which the metal is conveniently and economically extracted are not pure.So these impurities have to be removed .
The removal of unwanted earthly and siliceous impurities ( that is , gangue or matrix ) from the ore is called ore - dressing or concentration of ores and the process used to concentrate an ore is called the benefaction process .
Hence option A is correct .

Additional information :
Mineral processing or ore dressing involves four different unit operations.
1.comminution
2.sizing
3.concentration
4.dewatering
-Comminution is a process done to reduce the materials to particle size .The two basic methods to do this are crushing and grinding.
-Sizing is the separation of the particles of different size .This can be achieved by screening.
-Concentration is a method of increasing the amount of the desired minerals .This can be done by gravity concentration, froth flotation, electrostatic separation, magnetic separation, automated ore sorting.
-Dewatering is done to remove the water that the particles have absorbed which could have increased the pulp density.

Note:
The ore dressing of different ores is done through different methods which include hand picking , hydraulic washing , electromagnetic separation , electrostatic separation , froth floatation and leaching .