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