P204-TBP协萃体系用于乳状液膜提取铀(Ⅵ)的研究

    • 摘要: 介绍了P204-TBP协萃体系用于乳状液膜法提取铀(Ⅵ)的研究。研究了在乳状液膜法中协萃载体TBP的用量、乳状液膜制备条件、乳状液膜的膜相、膜内相和膜外相的组成对提取铀(Ⅵ)的影响。实验结果表明:(1)在硝酸铀酰体系中,膜相协萃载体TBP占载体总量20%—40%时,铀(Ⅵ)的分配比是单一载体P204的3倍左右;在硫酸铀酰体系中,也有明显协同萃取效应。(2)当表面活性剂Span80的体积分数为2%、膜内相H2SO4浓度为3—3.5mol/L时,可获得稳定的乳状液膜;膜外相pH控制在2左右,能获得满意的铀(Ⅵ)提取率;对铀(Ⅵ)含量较高的料液应该提高协萃载体浓度或适当增加乳状液与膜外相料液的体积比;料液中存在Fe3+离子对液膜提取铀(Ⅵ)会产生不良影响,而SO2-4离子的影响并不明显。(3)Na2CO3溶液虽然也是铀(Ⅵ)的良好反萃剂,但它不能作乳状液膜法中提取铀(Ⅵ)的膜内相。膜内相的选择不仅考虑它是合适的常规反萃剂,而且要考虑膜内相与膜相的相容性。

       

      Abstract: THERESEARCHONTHEUO2+2EXTRACTIONBEHAVIOURINTHEP204┐TBPSYNERGISTICEXTRACTIONEMULSIONMEMBRANESYSTEMXuMingxia(NuclearSafetyCentre,StateScience&TechnologyCommisionP.R.China,Beijing100088)TangBaolongZhuLanying(ChinaInstituteofAtomicEnergy,P.O.Box275(93),Beijing102413)ABSTRACTTheresearchontheUO2+2extractionbehaviourintheP204-TBPsynergisticextractionemulsionmembranesystemisintroduced.TheefectsofsynergistTBPonUO2+2extractionefficiencyintheconditionofP204ascarrierisstudied.Thepreparationconditionsofemul-sionliquidmembraneareselected.Theefectsofthecompositionoftheemulsionliquidmem-braneincludingtheinternalphase,theexternalphaseandmembranephasehavebeentested.Theresultsshowthat(1)WhenthemembranephasesynergistcarrierTBP:20%—40%tothetotalamountofthecarrier,theUO2+2distributioncoefficientfromUO2(NO3)2systemisincreasedbyabout3timescomparedwithsinglecarrierP204andsimilareffectisfoundforUO2SO4system.(2)Thestableemulsionliquidcanbeobtainedbyusing2%Span80asthesurfactantand3%—3.5%H2SO4solutionastheinternalphase.TheeficiencyofextractionforU(Ⅵ)issatisfiedinconditionofpH2inexternalphase.Themoreurany1inexternalphase,themoresynergistorthehigherratioofemulsionliquidtoexternalphasesolutionshouldbeused.TheunexpectedefectmightoccurwhenFe3+existsinexternalphasesolu-tion,buttheexistenceofSO2-4hasnoobviouseffectontheextractionofU(Ⅵ).(3)ThoughNa2CO3solutionisagoodstrippingagentforuranyl,butitcannotbeusedastheinternalphaseforemulsionliquidmembraneextractionofurany1.Therefore,theinternalphaseselec-tionshouldtakeintoaccountboththereagent′sstrippingabilityandthecompatibilitybe-tweentheinternalphaseandthemembranephase.KeywordsEmulsionliquidmembraneUranylSeparationP204-TBPsynergisticextractionsystem

       

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