Liquid-liquid extraction and separation of gallium (III), indium (III) andthallium (III) by Cyanex-925

A study of liquid-liquid extraction behavior of gallium (III), indium (III) , and thallium (III) with Cyanex-925 (Bis-2,4,4-trimethyl pentyl-n-octyl ph osphine oxide) was undertaken. Both gallium (III) and indium (III) were coe xtracted in the pH range 4.0-5.0 while thallium. (III) was extracted betwee n pH 2.0 and 4.0. The gallium, indium, and thallium ions were stripped out from the organic phase with 1.0 mol/L HNO3, 1.5 mol/L HCl, and 3.0 mol/L HC l, respectively. The optimum conditions of extractability were found separa tely as functions of pH, temperature, equilibrium time, and stripping abili ty. Based on these results, a sequential method was developed for the separ ation of gallium (III), indium (III), and thallium (III).