There are many ways to treat cadmium but the main emphasis has been to convert it to a cation and precipitate it as a hydroxide sludge. Electrowinned Cadmium cathodes should be kept under water. Zinc, Copper, Silver and Gold are also plated from cyanide baths.
Gold is recovered from ores as a cyanide.
This literature also applies to these metal complexes. Electrowinning works well for all of these metal cyanide complexes. Cadmium is plated from cyanide solutions so often cyanide destruction must be performed before the cadmium can be removed from solution. Full destruction is obtained by lowering the pH to 8.5 later and adding more oxidizer to destroy the cyanate. The following links will take you to sites that review the basic treatment technologies.