Abstract: In this paper through studying the extraction of uranium(Ⅵ)with some of amine, we have suggested and proved a new extraction mechanism of amine.The extraction reaction processes are considered in terms of the following steps:(1)The aggregation of ammonium salt and formation of reversed micelle in the extraction organic phase(see Eqn.1).(2)Metal ion Minteracts with monomeric amine to give an extraction complex(see Equ. 2).(3)The solubilization of extraction complex by the reversed micellar pseudophase(see Eqn.3).The distribution ratio Dof uranium can be described with Eqn.4.If the extraction complex does not bind significantly to the reversed micelle, i. e.K_c≈0 and Eqn. 4 reduces to:lgD = lgK_c+ylg[N]。Therefore, under these conditions, a plot of lgD versus ylg[N]。 has a slope of y, y is the number of molecules of amine extractant in extraction complex.In the second case, the ex traction complex interacts very strongly with the reversed micelles, i.e.K_s has a high val ue, therefore, Eqn.4 can be approximated as D=constant·Cslg Cs, gives a slope of unity, i.e.Dhas a first order dependence on the concentration of mi cellized surfactant.Thus in this case the formation of extraction complex is not confirmed by the usual slope method.According to the new extraction mechanism, our experimental data and those results in literatures can be given a satisfactory explanation.

Key words: Reversed micelle, Solvent extraction, Uranium