Solvent extraction of cadmium from alkaline cyanide solutions with quaternary amines

Quaternary amines are unique in their ability to extract metal cyanides from highly alkaline solutions. Cadmium cyanide extracts essentially quantitatively at both the subnanogram and macro levels. Regeneration of the amine solvent is achieved by stripping the cadmium with sodium hydroxide, sodium hypochlorite, or alkaline or acidic formaldehyde solutions. Because they readily extract free cyanide as well as anionic metab cyano complexes, the high-molecular-weight quaternary amines show considerable promise for industrial pollution abatement applications.