Regarding van Arkel process, correct statements are

A) It removes nitrogen and oxygen present in metals like Zirconium and Vanadium

B) Impure metal is heated with Iodine

C) An ionic metal iodide is formed

D) Volatile metal iodide decomposes at 1800 K

When impure metal is heated with iodine in an evacuated vessel, a volatile covalent metal iodide is formed. The metal iodide decomposes on electrically heated tungsten filament at 1800 K to give pure metal. During this process, oxygen and nitrogen are removed.

$\mathrm{Zr}\left(\mathrm{impure}\right)+2{\mathrm{I}}_2\to {\mathrm{ZrI}}_4\stackrel{1800 \mathrm{k}}{\to }\mathrm{Zr}\left(\mathrm{pure}\right)+2{\mathrm{I}}_2$