What is the composition of the anode mud in the electrolytic refining of silver?

In the electrolytic refining of metals,the electrolysis of an aqueous solution of its complex salt is performed using an impure metal as the anode and a strip of pure metal as the cathode. This method cannot be used for the refining of which of the following metals?

When copper is purified by the electrorefining process,noble metals like $Ag$ and $Au$ are found in:

Which metal is refined by Mond process?

The zone refining method is based on which principle?

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 $T_2$?