图书来源:二元合金相图及中间相晶体结构 二元合金相图及中间相晶体结构
作 者:唐仁政 田荣璋
出版时间:2009-05
定 价:320元
图书ISBN:978-7-81105-831-4
出版单位:中南大学出版社
Wang Yingwei Zheng Jianxiang(Department of Chemistry,Xiangtan University,Xiangtan 411105,P.R.China)
摘 要:<正> Reversed-phase paper chromatography technique is used for study on the extraction mechanism and sep-aration of rare earth elements.As the stationary phase,chromatographic paper strips are impregnated with asolution of monomyristyl phosphoric acid (MPA) in chloroform.Mineral acids are used as developers.The effect of concentration of acids and/or salts upon Rf has been investigated.According to the re-sults of Rf values for a given rare earth element in various acids,the order of extraction ability isHCl>HNO3>H2SO4.A tetrad effect is clearly observed.for the Rf value of rare earth elements.Theeffects of other parameters on the Rf value,such as the quantities of extractant retained by the paper and thetemperature are also examined.Based on the determination of the molar ratio of MPA to rare earth elementsand the number of H+ ions released in extraction reaction,a reasonable mechanism is proposed.The mutualseparation of heavy rare earth elements will be better than that of the light rare earth group because of thelarger separation coefficient of the former.A mixture of Ho-Er-Tm-Lu is successfully separated by thepresent method.
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