The Study Of New Enrichment And Separation Process Of Rare Earth Or Thorium

Compared with conventional metals,most rare earth metals have unique optical,electrical and magnetic properties.Therefore,rare earth elements have been widely used in petrochemical,metallurgy,environmental protection,new materials,new energy and other fields.Thorium is abundant in nature and fissionable,making it an alternative to uranium.Thorium is commonly associated with rare earth elements in minerals.In recent years,due to the lack of effective treatment of over-exploitation of rare earth resources and associated thorium resources,problems such as waste of resources and environmental pollution have resulted.In this paper,a new and efficient recovery process for rare earth elements and thorium was developed.Traditional carboxylic acid extractants such as CA-12,naphthenic acid have been applied to the extraction of rare earths,however,the process brought up many problems,such as large acid-base consumption,volatile organic solvent consumption,low extraction rate.To overcome the issuses exited in the conventional extraction process,a new carboxylic acid(4,4'-Isopropylidenebis(phenoxyacetic acid),H2IOPAA)was synthesized.On this basis,an ionic liquid[P66614]2[IOPAA]was prepared using[P66614]Cl and H2IOPAA.Firstly,the rare earth recovery ability of pure[P66614]2[IOPAA],pure[P66614][SOPAA]and pure[P66614]Cl were compared,and it was found that the recovery capacity of[P66614]2[IOPAA]was obviously better than the other two.The recovery mechanism of the pure[P66614]2[IOPAA]system was studied,it was found that[P66614]2[IOPAA]achieved the recovery of rare earths by using its anions and rare earth ions to form solid complex precipitates.Furthermore,under the conditions of 0.2358 g[P66614]2[IOPAA],4 mL feed solution of pH 4,a novel sustainable process for the rare earth enrichments from the simulated Nd-Fe-B feed solution using[P66614]2[IOPAA]as extractant was developed.In this paper,in order to optimize the recycling process of thorium,a novel synergistic extraction system of Cyanex 572 and neutral phosphorus extractant ODP(n-octyl diphenyl phosphate)was proposed.Compared with the traditional single extractant system,the extraction of Th(?)with this system shows a significant synergistic effect and avoids the problem of easy emulsification in a single extractant system.In addition,the synergistic extraction system can achieve stripping at low acidity.