【作者】 徐欣；

【导师】 李永绣；

【作者基本信息】 南昌大学 ， 无机化学， 2007， 硕士

【摘要】 本文以氯氧化锆（铪）为料液,P₅₀₇为萃取剂,研究了各种条件对锆铪萃取速度、萃取率、分配比和分离系数的影响。结果表明:P₅₀₇萃取锆铪的反应为吸热反应,萃取平衡时间≥40min。用斜率法求得的萃取反应焓变与萃取条件相关,表明P₅₀₇萃取锆铪的反应可能存在几种机理;改变萃取条件,或在有机相中添加仲辛醇可以缩短平衡时间,但均难以使萃取速率得到有效提高,说明萃合物的生成速度慢。采用饱和萃取法与等温线外切线法测得有机相中萃取剂与金属离子的物质的量之比均为3.6∶1。萃合物的红外光谱表明锆铪是以羟基聚合物形式与P₅₀₇配位而被萃取。大多数条件下锆为易萃组分,只有在低酸度和高Zr/P₅₀₇摩尔比值条件下才有利于铪的萃取。因此,锆铪之间的分离系数在1～4之间,随萃取剂浓度和其它条件的变化而变化。随P₅₀₇浓度的增加,分离系数β_Zr/Hf先降低而后增大,在1.0mol/L附近呈极小值;β_Zr/Hf的变化同样可以用锆铪萃取机制随萃取剂浓度的改变而不同来解释.相比增大可以提高萃取率,但分离系数在相比为1∶1时最佳。更多还原

【Abstract】 In this disertation,the effects of extraction conditions on the equilibrium time, distribution ratio and separation factor of Zr and Hf from Zr（Hf）OCl₂ solution were investigated using 2-ethyl hexyl phosphonic acid mono-2-ethyl hexyl ester(P₅₀₇)as extractant.The results showed that the extraction process is endothermic,and the equilibrium time is over 40 min.Some operation conditions can speed the extraction of Zr and Hf,however,the increase of extraction rate is still limited due to the slow formation process of extracted complex.The enthalpy changes of extraction reactions determined by slope method varied with the operation condition,indicating that the extraction mechanism was changeable in different test conditions.The molar ratios of metal ions to extractant in organic phase determined by isothermal method or saturation method were around at 3.6;1.The IR of extracted complex showed that Zr and Hf are extracted through the coordination of their hydroxyl polymer species with P₅₀₇.In most cases,Zr was extracted easier than Hf was,the reverse case only occured with low acidity and high Zr/P₅₀₇molar ratio.Therefore,the separation factor of Zr to Hf ranged from 1 to 4,and varied with extraction condition.With the increase of P₅₀₇concentration,β_Zr/Hfdecreased first and then increased,showing an minimal extremum at P₅₀₇concentration of 1 mol/L.The change ofβ_Zr/Hfcan also be explained by the extraction mechanism transition with extractant concentration.The extraction percentage of Zr and Hf also increased with the increase of phase ratio, however,the maximumβ_Zr/Hfwas observed when employing phase ratio of 1;1.更多还原