Preparation of Rare Earth Saponified P_(507)-kerosene Organic Phase and the Relating Reactions

In order to lower the consumption of base in the extraction separation of rare earths,RE saponification of P507-kerosene organic phase(P-kop) is being employed to replace sodium or ammonium saponification.The aim of this paper is to propose a method for the preparation of RE saponified P-kop with rare earth carbonate as saponification agents.Therefore,factors that influence on the rare earth loaded concentration in P-kop and the phase separation performance were examined,such as the dosage of rare earth carbonate,the content of impurity ions(SO2-4),the free rare earth ion concentration in aqueous phase and the phases ratio.It was found that when the P-kop is mixed with aqueous phase containing free rare earth concentration over 1mmol /l and solid rare earth carbonate,the saponification of P-kop can finish in a few minutes,which is much sooner than that when no free rare earth ions existing in aqueous phase because the kinetic limited direct saponification reaction has been changed by two separating reactions:the extraction reaction between P-kop and free rare earth ions and the dissolve reaction of rare earth carbonate with proton liberated from extraction reaction.With this characterization,the RE saponification of P-kop has been designed to a multi-stages counter-saponification process which continuously outputs RE saponified P-kop and remains the aqueous phase recycling.The results of simulation experiment in funnel prove that the multistage countercurrent saponification is feasible,and the optimum phase ratio is determined to be 1:1,the loaded rare earth concentrations in saponified P-kop reach 0.12 mol / L or more.