Write the principle behind the following methods of refining:
Hydraulic washing
Solution
The principle behind the given methods of refining are:
i) Hydraulic Washing:
This method is based on difference of gravity between ores and gangue. An upward stream of water is used to wash the powdered ore. The lighter gangue particles are washed away, leaving behind the heavier ones.
ii) Vapour-phase refining:
Vapour-phase refining is the process of refining metal by converting it into its volatile compound and then, decomposing it to obtain a pure metal. To carry out this process,
(i) the metal should form a volatile compound with an available reagent.
(ii) the volatile compound should be easily decomposable, so that the metal can be easily recovered. This method is used for refining nickel, zirconium and titanium.
