Separation and concentration of gallium from acidic leach solutions containing various metal ions by emulsion type of liquid membranes using TOPO as mobile carrier

The separation and concentration of gallium from acidic leach solutions, containing various other ions, such as iron, cobalt, nickel, zinc, cadmium, lead, copper, and aluminium, by an emulsion liquid membrane (ELM) technique using trioctylphosphine oxide (TOPO) as carrier has been presented. Liquid membrane consists of a diluent, a surfactant (ECA 4360J), and an extractant (TOPO), and 0.1 M HCl or 0.1 M H2SO4 were used as the stripping solution. The important variables governing the permeation of gallium and their effect on the separation process have been studied. These variables were membrane type and composition, mixing speed, surfactant concentration, HCl concentration in the feed, feed concentration, diluent type, extractant concentration, the acid type of stripping phase, and treatment ratio. The optimum conditions were determined. It was possible to selectively extract 97.0% of gallium from the acidic leach solutions, containing Fe, Co, Ni, Zn, Cd, Pb, Cu, and Al, at the optimum conditions. The separation factors of gallium with respect to Fe, Co, Ni, Zn, Cd, Pb, Cu, and Al, were experimentally found to be of 24.2, 16.2, 43.1, 28.3, 18.2, 25.2, 7.1, and 64.7, respectively, in 30 min. (C) 2004 Elsevier B.V. All rights reserved.