Question

Hydraulic separation method is used for the concentration of which ore?
A) Cassiterite
B) Haematite
C) Calamine
D) Galena

Answer 1

Hydraulic washing is used for the ores that have tin or lead in them. This is because tin and lead are heavier than the gangue particles.

Complete step by step answer:
The hydraulic separation method of concentration of ore is based on the difference in the specific gravities of the metallic ore and gangue particles. Generally, metal ores are heavier than the gangue particles. The hydraulic separation method uses this property for the concentration of the ore. Due to this reason, it is considered a type of gravity separation.
Cassiterite and haematite are concentrated with the help of the hydraulic separation method.

Cassiterite is the main ore of tin. It is a reddish, brownish, or yellowish mineral that consists of tin dioxide. It has the chemical formula as $Sn{O}_{2}$. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem.
Haematite is a common iron oxide ore. It has the chemical formula ${Fe}_{2}{O}_{3}$. It has a steel black color or we can say a silver-grey colour. It can also be brown to reddish-brown or red. It forms the shape of crystals.
During the hydraulic separation process, the powdered ore is washed by an upstream stream of running water. The lighter gangue particles are washed with the water leaving behind the heavier ore particles.
The ore is crushed to a fine powder and concentrated by gravity separation by washing with a current of water when most of the lighter gangue particles are removed.

_Hence, both (A) and (B) are correct. _

Note:
- Cassiterite has various properties like adamantine luster, light streak, high hardness, and high specific gravity which are helpful in its identification. Its high specific gravity, resistance to weathering and physical durability enable it to survive stream transport and concentrate in placer deposits.
- Haematite also has various properties like a metallic to splendid luster, bright red to dark red streak. It is not magnetic and can respond to a common magnet. It has a very strong grounding energy. It also has a cooling and calming effect.