【作者】 童辉；

【导师】 雷家珩； 李德谦；

【作者基本信息】 武汉理工大学 ， 材料学， 2003， 硕士

【摘要】 稀土材料是重要的新型功能材料，同时稀土也是改善传统材料性能，使材料产生新特性的重要改性剂和掺杂元素。本论文的主要工作是研究Cyanex923在硝酸体系中萃取稀土La（Ⅲ）、Y（Ⅲ）、Sm（Ⅲ）和Yb（Ⅲ）及其动力学，以及Cyanex923在不同盐析剂浓度、pH值及温度条件下的界面性质。探讨Cyanex923的界面特性与萃取效率之间的相互关系，为稀土元素的萃取提供重要的理论依据。 1、利用层流恒界面池，通过考察搅拌速度、温度和比界面积对初始萃取速率的影响，研究了用Cyanex923萃取稀土La（Ⅲ）、Y（Ⅲ）、Sm（Ⅲ）和Yb（Ⅲ）的传质模式。实验结果表明，用纯化Cyanex923萃取La（Ⅲ）、Y（Ⅲ）、Sm（Ⅲ）和Yb（Ⅲ）时，正向萃取表观活化能Ea分别为32.0KJ·mol^-1、16.4KJ·mol^-1、15.1KJ·mol^-1和19.2KJ·mol^-1；用未纯化Cyanex923萃取Yb（Ⅲ）时，正向的萃取表观活化能为12.9kJ·mol^-1。纯化Cyanex923萃取La（Ⅲ）的过程为混合控制过程，对Y（Ⅲ）、Sm（Ⅲ）和Yb（Ⅲ）的萃取过程为扩散控制过程；未纯化Cyanex923萃取Yb（Ⅲ）过程也为扩散控制过程。萃取过程的化学反应主要发生在液—液界面上，而不是在本体相内。 2、通过考察水相离子强度、酸度和有机相浓度对萃取速率的影响，获得了Cyanex923萃取La（Ⅲ）、Y（Ⅲ）和Yb（Ⅲ）的速率方程。实验结果表明，随着Cyanex923浓度的增加，萃取机理会发生改变。萃取剂Cyanex923中的杂质成份在萃取Yb（Ⅲ）的过程中，不仅具有热力学协萃作用，而且还具有很强的动力学协萃效应。 3、利用Sigma701型界面张力仪，研究了温度、离子强度、pH值和不同稀释剂对萃取剂Cyanex923的界面性质的影响，得到了Cyanex923在不同条件下的界面吸附参数。 4、根据用Cyanex923萃取稀土的界面特性和萃取动力学的相关信息，探讨了萃取上述RE（Ⅲ）的动力学机理，为进一步开发和利用我国的稀土资源提供了重要的基本数据和理论指导。更多还原

【Abstract】 The materials of rare earth are important function materials. Rare earth elements are important modification agents and adulterate elements, which can improve the properties of traditional materials. The solvent extraction kinetics of La(Ⅲ), Y(Ⅲ), Sm(Ⅲ) and Yb(Ⅲ) with Cyanex923 in n-heptane from nitrate medium and the interfacial properties of Cyanex923 have been investigated. The goal of this work is to further understand the relationship between the interfacial properties of Cyanex923 and the initial extraction rate, and to offer evidences for extraction mechanism and fundamental information for the applications of solvent extraction of rare earth.1. Using a constant interfacial cell with laminar flow, mass transfer kinetics of La(Ⅲ), Y(Ⅲ), Sm(Ⅲ) and Yb(Ⅲ) has been studied. The effects of stirring speed, temperature and specific interface on extraction rate have been reviewed. The results show that the values of apparent activation energy (Ea) of purified Cyanex923 extraction are 32.0KJ.mor-1,16.4 KJ.mol-1, 15.1 KJ.mol-1 and 19.2 KJ-mol"1, respectively. Ea of Yb(IQ) with unpurified Cyanex923 extraction is 12.9 KJ.mol-1. The mass transfer of La(m) is controlled by mixed controlled process, the others are controlled by diffusion. The chemical reactions of extraction process occur at the interface.2. The equations of initial extraction rate of La (Ⅲ), Y (Ⅲ) and Yb (Ⅲ) have been obtained. The results show that the extraction mechanism may be changed with the increasing of concentration of Cyanex923. During the process of extraction Yb(Ⅲ), the impurities of Cyanex923 have better kinetic synergism.3. Using Sigma 701 interfacial tension instrument, the effects of temperature, ion strength, pH value and different thinner on the properties of Cyanex923 have been studied. The interfacial parameters on extractant are obtained.4, According to the interfacial adsorption properties of Cyanex923 and the information of extraction kinetics, the mechanisms of extraction RE(Ⅲ) have been analyzed.更多还原