Which among the following elements is obtained in pure form by the liquation process of refining?

The zone refining of metal is based on the principle of

The formation of $Ni(CO)_4$ and its subsequent decomposition into $Ni$ and $CO$ forms the basis of the Mond process.
$Ni + 4CO$ $\xrightarrow{T_1} Ni(CO)_4$ $\xrightarrow{T_2} Ni + 4CO$
What are the values of $T_1$ and $T_2$?

Zone refining is based on the principle of

What is formed as anode mud after the electrolytic refining of copper?

Which of the following elements is purified by vapour phase refining?