In this study, a wet refining process for indium purification was developed aiming at the problem that the electrolysis refining method is difficult to remove cadmium, lead (Pb), and tin in indium, so as to reduce the energy-consuming and time-consuming process of smelting at the same time. The original electrolyte made by crude indium (99%) is co-precipitated to remove lead and pre-electrified to remove tin, and then heated to activate indium ions during electrolysis refining to reduce the electrodeposition of Cd²⁺, and the purity of electrodeposited indium can reach 99.99% after only once electrolysis refining like this. The mechanism of the removal of Pb²⁺ by co-precipitation is also discussed: 1–6 ppm Pb²⁺ is in the metastable region (dissolution and crystallization), and cannot nucleate spontaneously, but as long as there is a surface charged solid in the solution, which can provide Coulomb force, Pb²⁺ can be induced to grow on solid with SO₄²⁻, regardless of crystal form, chemical configuration, and ion type. This viewpoint can explain some anomalous phenomena which cannot be explained well by the traditional co-crystallization and co-precipitation theory. In addition, it is the first observed that temperature plays an extremely important role in the separation of In³⁺ and Cd²⁺ in the electrolytic refining process. During electrolytic refining at 40 °C, even though the concentration of Cd²⁺ in the solution is as high as 200+ ppm, the content of cadmium in the electrodeposited Indium meets the standard of 4 N-Indium, while In³⁺ and Cd²⁺ are generally considered cannot be removed by electrolytic refining because their electrode potentials are too similar. The mechanism is also explicitly explained: the In³⁺ electrodepositing process is mainly controlled by activation, and the electrochemical reaction resistance decreased to 1/4 of the original with the increase of temperature, so that the cathode only needs a smaller overpotential to achieve the expected current, reducing the amount of Cd²⁺ electrodeposition in the cathode.

本研究针对电解精制方法难以去除铟中的镉，铅（Pb）和锡的问题，开发了一种用于铟精制的湿法精制工艺，以减少能耗和时间。同时冶炼的过程。将由粗铟（99％）制成的原始电解质进行共沉淀以去除铅，并进行预电去除以去除锡，然后在电解精炼过程中加热以激活铟离子以减少Cd ²⁺的电沉积以及电沉积的纯度像这样电解精炼一次，铟就可以达到99.99％。还讨论了通过共沉淀去除Pb ²⁺的机理：1–6 ppm Pb ²⁺处于亚稳区域（溶解和结晶），不能自发成核，但是只要溶液中存在可以提供库仑力的表面带电固体，就可以诱导SO ₄ ²在固体上生长Pb ^2+。−，与晶体形式，化学构型和离子类型无关。这种观点可以解释一些异常现象，而这些现象是传统的共结晶和共沉淀理论无法很好解释的。另外，首次观察到温度在电解精制过程中在In ³⁺和Cd ²⁺的分离中起着极其重要的作用。即使在Cd ²⁺浓度为40°C的电解精炼过程中溶液中的含量高达200+ ppm，电沉积铟中的镉含量符合4 N-铟的标准，而通常认为In ³⁺和Cd ²⁺不能通过电解精制去除，因为它们的电极电位为太相似了。机理也得到了明确的解释：In ³⁺电沉积过程主要受活化控制，随着温度的升高，电化学反应电阻降低到原来的1/4，因此阴极只需较小的超电势即可实现预期电流，从而减少了阴极中Cd ^2+的电沉积量。