Explain the Van Arkel method with an example.

(N/A) The Van Arkel method is very useful for removing all oxygen and nitrogen present as impurities in certain metals like $Zr$ and $Ti$.
The crude metal is heated in an evacuated vessel with iodine. The metal iodide,being more covalent,volatilizes.
$Zr + 2I_2 \rightarrow ZrI_4$
The metal iodide is decomposed on a tungsten filament electrically heated to about $1800 \ K$. Thus,the pure metal is deposited on the filament.
$ZrI_4 \rightarrow Zr + 2I_2$