In the extraction of nickel by the Mond process,the metal is obtained by:

Formation of $Ni(CO)_4$ and its subsequent decomposition into $Ni$ and $CO$ (recycled) forms the basis of the Mond process.
$Ni + 4CO$ $\xrightarrow{T_1} Ni(CO)_4$ $\xrightarrow{T_2} Ni + 4CO$
$T_1$ and $T_2$ are:

Which metal is refined by Mond process?

In vapour phase refining,metal $A$ is purified by Van Arkel method and metal $B$ is purified by Mond's process. $A$ and $B$ are respectively:

The method used for producing semiconductor grade metals of high purity is

Which method is not correct given for refining of crude metals?