Question

Write the chemical equations involved in van Arkel method for refining zirconium metal.

Answer 1

Impure Zr is heated with iodine. Volatile iodide of zirconium is formed. It is then heated (above 1800 K) with a tungsten filament. Pure metal is deposited on the filament.

$Zr\left(\text{impure}\right)+2I_2\to Zr{I}_4\left(\text{vapour}\right)$

$Zr{I}_4\left(\text{vapour phase}\right)\to Zr+2I_2$