Extractive Separation of Thorium, Uranium and Rare Earths from Nitrate Medium by Cyanex 272

The extractive separation of thorium, uranium, iron, titanium and lanthanides, represented by lanthanum, yttrium and cerium, has been investigated by Cyanex272 into the synthetic nitrate solutions. The concentration of each studied element in the synthetic solution was 10-4 M. It was found that the extraction increases in the order of La(III)<Ce(III)<Y(III)<Fe(III)<Th(IV)<U(VI)<Ti(IV). Thorium was optimally separated utilizing 0.5 M nitric acid solution. The slope analysis method showed that thorium was extracted as Th(OH)2(NO3)A.HA. Also, the effects of complexing agent, acid type and acid concentration on the stripping of thorium, uranium, lanthanum and iron from the loaded organic phase were studied by Taguchi method. The optimum conditions for the selective stripping of thorium were observed when 0.5 M sulfuric acid and 2.7´10-4 M EDTA were used. The thermodynamic functions have been calculated.