Solvent extraction of Am(3) from nitric acid by the mixtures of neutral organic phosphorus reagents

Am(3) extraction by the mixtures of dialkyl[diaryl dialkylcarbamoylmethyl]phosphine oxides (KMPO) and TBP from nitric acid solutions, depending on the concentration of the system components and diluents used, has been investigated. It is shown that when TBP is added to KMPO solutions a non-additive change in americium distribution coefficients (D) (synergism and antagonistic effects) is observed. The values of the effects and the range of their pronouncement depend on the nature of KMPO and diluent. The value of synergism S increase with an increase in TBP:KMPO concentration ratio, with a conciderable increase in the concentration of KMPO and HNO3 concentration <3 mol/l the antagonistic effect can be observed (S<1), which is put down to the change in KMPO activity coefficient. Dependence of S and D on TBP increases with an increase in HNO3 concentration, which is related to the change of americium extraction mechanism with KMPO and different role of TBP in non-additive change of D in case of different extraction mechanisms