Uranium with synergistic systems

Synergistic systems have also been reported in which one of the adducts is in the aqueous phase. The combination of TOPO (in CCI4) and benzoic acid (in aqueous and organic) was shown to extract uranium with a synergistic effect. The organic-phase adduct was reported to be 1102(0104) C COO TOPO. An optimum benzoic acid/TOPO ratio exists, above which compound formation between TOPO and benzoic acid decreases the synergistic effect (91). 

The alkyl phosphoric acids were first recognized as excellent actinide extractants because dibutyl phosphoric acid existed as an impurity in TBP (8). They extract well from unsalted solutions and from systems such as sulfate in which TBP is ineffective. Organo-phosphorus acids are thus suitable for uranium hydr metallurgical applications where ore is leached with sulfuric acid. The Dapex process is an example in which bis(2-ethylhexyl) phosphoric acid (HDEHP) is used alone or in synergistic combination with neutral organophosphorus compounds for uranium and vanadium recovery (9,10). 

---