Question

Describe the role of Iodine in the refining of zirconium.

Answer 1

Impure zirconium is heated with iodine to form volatile compound $Zr{I}_4$ which on further heating over tungsten filament decomposes to give pure zirconium.

$\underset{Impure}{Zr}+2I_2\stackrel{870K}{\to }Zr{I}_4\stackrel{2076K}{\to }\underset{Pure}{Zr}+2I_2$.