Question

What is the process used in refining either Zirconium or Titanium?

Answer 1

Refining is the final step of extraction, which involves removal of last small amounts of impurities left after the major extraction techniques. The refining step will give metal in a practically pure state for commercial application.

Complete answer:
We have seen what is refining, now let’s come to our question.
For the refining of Zirconium or Titanium Van Arkel method is used.
In this method impurities present in Zirconium or Titanium in the form nitrogen and oxygen are removed. The crude metal is firstly heated in an evacuated vessel at $870$ K with iodine to form metal iodide. The metal iodide being more covalent, volatilizes leaving the impurities behind.
$Zr + 2{I_2} \to Zr{I_4}$
In order to recover the pure metal, metal iodide is decomposed on a tungsten filament. It is electrically heated to $1800$ kelvin. The pure metal is then obtained on the filament.
$Zr{I_4} \to Zr + 2{I_2}$
Thus, we have recovered pure metal.

Additional information: Some metals are required in their purest form for certain specific applications. Van Arkel method is one of those methods of refining that produces ultrapure metals. This method is based on vapour phase refining. The main conditions are;
The metal should form a volatile compound with the available reagent.
Volatile compounds should be easily decomposable so that the recovery of metal is easy.

Note:
We have seen that the Van Arkel method is used for refining Zirconium or Titanium. This method is used to get ultrapure metals. Along with the Van Arkel method, Zone refining is also known as ultra purification technique.