The Van Arkel method is used to filter Zr and Ti. Van Arkel’s process involves heating the impure metal with Iodine. It builds a complex structure where it decomposes at high temperatures, restores metal but is in excellent condition.

Refining Zirconium,

Zr(impure) + 2I₂ → ZrI₄

At 1800K,

ZrI₄ → Zr(pure) + 2I₂

Refining Titanium,

Ti (impure) + 2I₂ → TiI₄

At 1800K,

TiI₄ → Ti (pure) + 2I₂