Abstract
This study describes the use of the emulsion liquid membrane (ELM) technique to recover thorium (Th(IV)) from an aqueous nitrate solution. The components of the ELM were kerosene as a diluent, sorbitan monooleate (span 80) as a surfactant, bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) as an extractant, and H(2)SO(4) solution as a stripping reagent. Th(IV) was more successfully extracted and separated under the following favorable conditions: Cyanex272 concentration of 0.11 mol/L; 0.65 mol/L H(2)SO(4) as a stripping phase (internal phase); feed phase (external phase) pH of 1; internal-to-membrane phase volume ratio of 1; emulsion-to-external phase volume ratio of 0.4; contact time of 25 min; and agitation speed of 300 rpm. Under these conditions, the membrane transferred Th(IV) selectively from the real leach liquor without appreciable emulsion breakage or swelling.