电解稀土在多种阴极上形成合金的析出电位递变规律研究

In this project, molten salt electrolysis on rare earth alloys is proposed. The deposition potential grading rule and electrochemical behavior of rare earth on the active liquid, semi-solid and solid cathodes will be emphatically investigated. The thermodynamics, dynamics, and alloy formation mechanism of the deposition process of rare earth electrolysis will be clarified. The aim of this project is to establish the mathematical model from the relationship between deposition potential of rare earth on various cathodes and rare earth radius, cathode metallic radius, and crystal cell parameters. The mathematical relationship equation between deposition potential of rare earth and rare earth radius, cathode radius and crystal cell parameters will be derived. Using the mathematical equation, the behavior rule of rare earth on different cathodes and the energy relationship of alloy formation will be described. Based on this model and equation, the deposition potential of intermetallic compounds of actinides element, transition element, alkaline earth metal will be precisely extrapolated and obtained, and used to guide alloy electrolysis research based on metallic radius. This model or equation will be applied to the preparation of random two metallic alloys, and provide reliable and credible potential values for the accurate electrolysis preparation of binary and multicomponent alloys. We will clarify the formation mechanism of rare earth alloys and other metallic alloys in theory, and provide the scientific basis to the discovery of a new alloy, electrolysis preparation, electrolysis separation and extraction.

本项目提出稀土合金的熔盐电解研究，着重研究稀土在活性液态阴极、半固态阴极、固态阴极上沉积的电化学行为及析出电位的递变规律，认清稀土电解析出过程热力学、动力学和合金形成机理。本项目旨在由熔盐电解稀土在多个阴极上的析出电位与稀土半径、阴极金属半径之间的关系，析出电位与合金晶胞参数之间的关系，建立数学模型，推导稀土析出电位与稀土半径以及阴极半径之间关系和析出电位与合金晶胞参数之间关系的数学方程，用数学方程描述稀土在不同阴极上的行为规律以及合金形成的能量关系，将所得的方程外推到锕系元素、过渡族元素、碱土金属，使之能够依据金属半径就能够准确推断出其形成合金的析出电位，用以指导合金电解研究。将该方程用于任意两种金属合金的电解制备中，为实现二元乃至多元合金的精准电解制备提供可靠可信的电位值，从理论上诠释稀土合金以及其他金属合金的形成机理，为新合金的发现、电解制备、电解分离与提取提供理论科学依据。

在氯化物熔盐体系中，有序的针对镧系元素在不同阴极（锡、铅、钴、铝、镍以及铜）在KCl-LiCl熔盐体系中共沉积的沉积电位和电化学过程开展实验和理论研究。根据不同温度下的电化学行为以及电解过程动力学和热力学，确定最佳配比和最佳工艺参数。利用多种电化学方法表征合金元素共沉积的电化学过程并获得相关电化学参数，采用微观分析方法（包括XRD和SEM）等对合金进行分析测试，探明其微观结构。将大量实验数据通过数学模型的模拟，建立出电解镧系元素在阴极沉积析出的沉积电位与镧系元素半径、阴极金属半径之间相互关系的数学模型，ERE-alloy=f(r1, r2)，推导出公式：1/(E*r3)=a(x1lnx1+x2lnx2)+b。结果表明：发现该数学方程不受温度的影响，可以通过使用拟合的数学方程来合理地预估镧系元素和锕系元素在活性阴极上的电化学，这为镧系元素在基于电解的热加工中的行为提供了初步的模型和理论基础。并且可以根据任意两种元素的半径推断出形成的合金在某一特定温度下电解析出的沉积电位。