Synthesis Of Aminophosphine Extractant And The Applications In Separation Of Thorium And Rare Earths

China is a major country with abundant rare earth resources.The rare earth resources are essential strategic for high-tect industries and play an important role in economic development.There is no independent deposit of rare earth,it often coexists iron and other metals in rare earth minerals,such as bastnaesite and baotite,etc.It is difficult to separate rare earths from each other because they have the similar radii and the similar physicochemical properties.The traditional extractant HEHEHP has low separation factors and high stripping acidity.The saturated extraction capacity of Cyanex272 is small.Therefore,it is urgent to design and investigate an efficient,clean and green method to separate and extract rare earths.In this work,nitrogen-containing amine-phosphine bifunctional extractant was synthesized successfully by introducing an amino group to phosphine extractant,which was applied to separate RE(?)in nitrate medium.The nitrogen-containing amine-phosphine bifunctional leaching extractant CMPSNP was synthesized successfully by bonding the amino group and phosphoryl group to resin CMPS,which was applied to separate Th(?)and RE(?)in sulfate medium.The main research contents are as follows:1.A new ?-aminophosphine extractant(EEAMPA,HA for short)was synthesized by introducing anino group to extractant P227,which was used to separate trivalent rare earth ions in nitrate medium.The influence of concentration of the extractant,the concentration of nitric acid and temperature on the extraction of RE(?)was studied systematically.The results of experiments shown that the extraction ability of EEAMPA for RE(?)decreases with increasing acidity.A possible extraction mechanism is proposed and the extracted species as REHA3NO3 are confirmed by the slope analysis method.The extraction equilibrium time is shorter than P227,the saturation capacity is larger than Cyanex272,the strriping acidity is lower than HEHEHP.The cycle experiment shown that extractant EEAMPA has a good chemical stability and cycling stability.2.The function groups of amino and phosphoryl,which have excellent separation ability for rare eart elements,were bonded to the resin CMPS(chloromethylstyrene-divinylbenzene)by chemical bonding method.The ability of separation Th(?)from RE(?)was investigated.It was studied that the influence of the concentraction of sulfuric acid,the equipment time and the number of cycles on absorbtion ability.The adsorption percent of levextrel resin CMPSNP for Th(?)decreases with increasing acidity.Among the action kinetic model,the pseudo-second-order kinetic model provided the best fit,the correlation coefficient R2 is 0.9997.Therefore,the adsorption process is chemisorption.The experiment of adsorption-desorption shown that the levextrel resin CMPSNP has a good chemical stability and cycle stability.It was applied to recovery of Th(?)from the radioactive residue of rare earth industry finally.