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These are following extraction process of silver but not :
as a side product in electrolytic refining of copper
Parke's process in which $Zn$ is used to extract silver by solvent extraction from molten lead
by reaction of silver sulphide with $KCN$ and then reaction of soluble complex with $Zn$
by heating $Na[Ag(CN)_2]$
Solution
The Parkes process is a process for removing silver from lead.
Electrolytic process gives the highest-purity metal product as well as the best recovery of valuable impurities. It is used for copper, nickel, lead, gold, and silver.
Reactions occurs in extraction of silver-
$Ag _2 S +4 NaCN \rightarrow 2 Na \left[ Ag ( CN )_2\right]+ Na _2 S$ (reversible reaction)
$2 Na \left[ Ag ( CN )_2\right]+ Zn \rightarrow Na _2\left[ Zn ( CN )_4\right]+2 Ag$
here we can also use $K$ instead of $Na$.
But by heating of $Na \left[ Ag ( CN )_2\right]$, $Ag$ is not produced as on and heating $Na \left[ Ag ( CN )_2\right]$ forms a complex product of $Ag$ and not simple $Ag$.
