Study On Extraction Separation Of Neodymium And Samarium By N1923-P507Non-saponification Synergistic Extraction System

This topic mainly adds a kind of amine extractant N1923which can absorb hydrogen ionsto acid extraction agent P507,as amine extractant of N1923has a certain capacity of combininghydrogen ions.N1923adds to the extractant P507to absorb hydrogen ions which the acidextraction agent ion-exchange released in the process of extraction,thus accomplishing thenon-saponificationextraction ofacid extraction agent.In order to discuss the effect to absorbing hydrogen ion and the performance of P507extraction of rare earths after adding N1923,extraction performance of the rare earth ions andhydrogen ions effect by N1923was studied at first in this paper.The results prove that N1923iscapable of extracting hydrochloric acid,at the same time rally don’t extract rareearths.Synergistic extraction agent has a batter ability to extract rare earths after acidtreatment.Then the paper researched extraction behaviors and its mechanism such asneodymium and samarium distribution ratio and separation factor effects of two kinds ofextractant ratio,the extractant concentration,phase ratio,pH and concentration of rare earth in theN1923-P507synergistic extraction system.The research results list as follow:the extraction ofneodymium and samarium have obvious positive synergy with the N1923-P507non-saponification synergistic extraction system and the most-positive synergistic coefficientsare3.52and2.18respectively.Under the condition of the most-positive synergicratio,extraction time is5min, and phase ratio is1:1,and the initial aqueous phase pH is2.5,andextraction of neodymium and samarium distribution is the biggest.The extraction saturationcapacity of neodymium is28g/LREO,and the extraction saturation capacity of samarium is38g/LREO.The separation factor as high as2.2from researching single rare earth element, theseparation factorobtained up to9fromresearching mixedrareearthelements.The study of the mechanism of samarium and neodymium in the N1923-P507non-saponification synergistic extraction system discovered that extraction process can bedivided into three stages according to the relationship between the pH of initial water phase andthe pH of balance water phase value.When the initial aqueous phase pH<2.5,synergisticextraction organic phase not only absorbed the hydrogen ion that the acidic extractant releasedalso absorbed hydrogen ion in aqueous phase;pH=2.5,synergistic extraction organic phase cancompletely absorb the hydrogen ion the acidic extractant released and without absorbing hydrogen ion in aqueous phase;PH>2.5,synergistic extraction organic phase only absorbed thepart of hydrogen ion the acidic extractant released.The ion-exchange reaction can occurbetween H of P-OH in P507and rare earth ions,at the same time P=O combined with rare earthions in the form of coordination, and N1923mainly existed in extracted complexes in the formof ion association by ammonium salt generated by the N1923and rare earth ions in synergisticextractionand separation ofrareearthelements.Finally,the paper researched the stripping property effects of time,phase ratio，hydrochloric acid concentration,rare earth concentration of loaded organic phase in theN1923-P507synergistic extraction system.The stripping ratio is the best on the condition thatextraction time is5min,and phase ratio is1:1,and the strip liquor hydrochloric acidconcentration is3mol/L.In this condition,the stripping ratio is not affected by the rare earthconcentration in the load of organic phase.Studies have shown that the N1923-P507non-saponification synergistic extraction system can improve the ability of acid extractionsolvent extraction through absorbing hydrogen ions released by acid extraction agent in theheart of the extraction process,and reduce the cost due to the saponification treatment andenvironmental problems.To do a certain theoretical basis research for the development ofnon-saponificationprocess.