THE RULE OF TRANSITION OF EXTRACTION KINETICS BEHAVIOR OF RARE-EARTH ELEMENTS WITH HEH(EHP)

On the basic theory of extraction kinetics, the rule of transition of extraction kinetics behavior of rare earth elements with 2-ethyl hexyl 2-ethyl hexyl phosphonic acid [HEH(EHP), P-507] has been studied using stirred Lewis cell in this paper. The transformation rules of distribution ratio and separation factor of rare earth elements with time are disscussed, The forward rate constant (kf) and the backward rate constant (kb) are measured, The ''tetrad effect'', the ''oblique W effect'' and the ''gadolinium break'' phenomenon of the rate constants have given for the first time in extraction kinetics.