Question

Which physical process is used to separate the pulverised ore?
(A) Hydraulic washing
(B) Froth – floatation
(C) Magnetic separation
(D) All of the above

Answer 1

Hint: A pulverised ore can be separated from its ore by either through physical process or chemical process.

Complete step by step answer: The process of applying an external force to a (solid) material of a certain size to destroy it and reduce it into pieces that are smaller than the original size is called “Pulverisation”. Pulverization has long been done for many materials, including ore, glass, ceramics, grains, paints, and medicines. The term is also known as comminution, crushing, and grinding.
The processes used for removing the gangue, valueless substance from the ore are based on the differences between the physical or chemical properties of the gangue and the ore. At first, the ore is crushed to powder. The pulverized ore is separated by physical processes like hydraulic washing, froth-floatation and magnetic separation or by chemical processes depending on the nature of the ore and its impurities.

So, the correct option is D.

Note: All the three physical processes namely, Froth floatation, Hydraulic washing and magnetic separation are used in separation of pulverised ore but these methods differ in their principle of separation.
- In Froth floatation, the gangue is separated from the ore based on differences in their hydrophobicity. The floatation process is used for the separation of a large range of sulphides, carbonates and oxides prior to further refinement.
- In Hydraulic Washing, based on the difference in gravity of the particles of the gangue and the ore are separated. Thereby, it is also known to be a type of gravity separation. The exact working during this process is that an upward stream of running water is used to wash the powdered ore. The lighter gangue particles are washed leaving the heavier ore particles.
- Magnetic separation is the process of separating components of mixtures by using magnets to attract magnetic materials. By this separation, we will be able to detach non-magnetic material from those that are magnetic.