Selective zinc-lead extraction from chloride solutions with long-chain amines

The zinc-lead separation from a chloride solution in the form of a synthetic leach liquor has been studied using tertiary aliphatic amines and tetra-alkylammonium salts. Larger extractions, and hence distribution coefficients, are observed with ammonium salts. However, the best separation factors occur when employing tertiary amines. The results show that it is possible to leave the lead in the aqueous solution whilst the zinc is transferred to the organic phase by a proper choice of the hydrochloric acid and extractant concentrations. An approach to coordination chemistry is suitable to explain the extraction mechanism.