Extraction and concentration study of cadmium from zinc plant leach solutions by emulsion liquid membrane using trioctylamine as extractant

The cementation cake (CINKUR Co., Turkiye) was leached with hydrochloric acid. The extraction and concentration of cadmium from these acidic leach solutions, containing various other ions, such as zinc, iron, lead, aluminium, copper, cobalt, and nickel, by an emulsion liquid membrane (ELM) using trioctylamine (TOA) as extractant were studied. The study has highlighted the importance and influence of membrane composition for maximizing the extraction of cadmium. The ELM consists of trioctylamine as an extractant, commercial kerosene as a diluent. Span 80 as a surfactant and 6 M ammonia solution as a stripping solution. The important factors studied which affect the ELM stability and extraction of cadmium are acid and cadmium concentrations in the acidic leach solution, mixing speed, type and concentration of the stripping solution, extractant concentration, surfactant concentration and phase ratio. The results showed that it is possible to extract 98% of cadmium after 10 min contact time by using ELM from the acidic leach solutions, containing Zn, Fe. Pb, Al, Cu, Co and Ni ions, at the optimum operating conditions. (C) 2008 Elsevier B.V. All rights reserved.