三维通孔Pb合金基梯度功能阳极的结构设计及其在铜电积中的应用基础研究

In order to solve the problems of high power consumption and short service life caused by high oxygen evolution over-potential and poor corrosion resistance of Pb-Ca-Sn anode used in copper electrowinning process, A 3D through hole Pb alloy based gradient functional anode is designed. Firstly, porous lead matrix is prepared via foam copper template, and then PbO2-WC and Co3O4 functional layers are coated on the matrix, finally, an energy-saving anode for copper electrowinning with low oxygen evolution over-potential, strong corrosion resistance and excellent oxygen evolution catalytic activity is obtained. The project will centres on the seepage of lead alloy melt in foam copper, dissolution of copper templates, corrosion behavior and electrocatalytic mechanism of PbO2-WC and Co3O4 functional layers in copper electrowinning system. This project will focus on discussing the influence of the porosity of new anode, composition and thickness of functional layer on oxygen evolution potential, corrosion behavior of surface layer and the formation process of anode slime. The influence of co-deposition process on the interfaces adhesion of gradient functional anode is studied, and the electrochemical process model of the surface of anode is established, which provides theoretical guidance for the design of high-performance anode. Therefore, the implementation of the project is expected to provide theoretical basis and technical support for development and application of new anode for copper electrowinning.

针对铜电积工序现行铅钙锡阳极析氧过电位高、耐腐蚀性差而导致电耗大、寿命短的问题，项目设计了一种三维通孔Pb合金基梯度功能阳极。该阳极首先以泡沫铜为模板制备出多孔铅合金基体，然后在基体上依次着覆PbO2-WC与Co3O4功能层，以获得具有低析氧过电位、强耐腐蚀性和优良析氧催化活性的铜电积用节能阳极。项目将围绕铅合金熔体在泡沫铜中的渗流、铜模板的溶出、PbO2-WC与Co3O4功能层在铜电积体系中的腐蚀行为与电催化机理开展研究，将重点探讨新型阳极孔隙率以及功能层组分与厚度等对析氧电位、表面膜腐蚀行为以及阳极泥形成过程等的影响规律，研究共沉积过程对梯度功能阳极各界面结合力的影响，建立阳极表面的电化学过程模型，为高性能阳极的设计提供理论指导。项目的实施有望为铜电积用新型阳极的开发和应用提供理论依据和技术支撑。

为解决现行铜电积过程由于所采用Pb-Ca-Sn阳极析氧过电位高、耐腐蚀性差而导致电耗大、寿命短的问题，本项目提出了3D-Pb-Ca-Sn合金为基底、PbO2-WC为镀层的复合阳极，以降低阳极析氧过电位、提高其耐腐蚀性和析氧催化活性。新型阳极的制备过程包括泡沫铜的表面处理、熔融Pb-Ca-Sn合金的渗流得到泡沫铜/Pb-Ca-Sn前驱体以及泡沫铜模板的溶解去除和3D-Pb-Ca-Sn合金基底上镀覆PbO2-WC层等工序。系统研究了3D-Pb-Ca-Sn阳极在不同电解液体系中的电化学行为后发现：与传统的Pb-Ca-Sn合金相比，3D-Pb-Ca-Sn阳极具有较低的阳极电位、析氧过电位和槽电压以及较高的交换电流密度。在电流密度为200 A /m2时，3D-Pb-Ca-Sn阳极的析氧过电位为0.702 V，比Pb-Ca-Sn阳极低75 mV，具有潜在的节电能力。这些特征主要由于3D-Pb-Ca-Sn阳极比表面积的增加。此外，虽然电解液中Cl-的存在会增强阳极的腐蚀，但电解液中Mn2+和新型阳极良好3D结构的共同作用增强了3D-Pb-Ca-Sn阳极层的稳定性。因此，本项目所研制的新型阳极是一种不会引入有害杂质、可实现节能并有望成为一种性能优良的铜电积阳极材料。