Describe a method for refining nickel.

(N/A) Nickel is refined by $Mond's$ process.
In this process,impure nickel is heated in the presence of carbon monoxide $(CO)$ at $330-350 \ K$ to form nickel tetracarbonyl,which is a volatile complex:
$Ni(s) + 4CO(g) \xrightarrow{330-350 \ K} Ni(CO)_4(g)$
Then,the obtained nickel tetracarbonyl is decomposed by subjecting it to a higher temperature $(450-470 \ K)$ to obtain pure nickel metal:
$Ni(CO)_4(g) \xrightarrow{450-470 \ K} Ni(s) + 4CO(g)$