Vapour phase refining :

It is a process of metal refining in which the metal is converted into a volatile compound, which is then decomposed to obtain the pure metal.
(1) To accomplish this, the metal must first be converted into a volatile compound using a reagent.
(2) The metal’s volatile component must be able to disintegrate quickly enough for the pure metal to be recovered.
This process is used to purify zirconium, titanium, and nickel.