| At present, nonferrous metals has become an important material basis for the development of science, technology, national economy, national defense construction and so on, it is a key strategic resource to improve the country’s comprehensive strength and safeguard national security.The process of electrochemical extraction is becoming more and more important in the field of non-ferrous metal extraction, and the choice of electrode material directly affect to the whole reaction process of electrochemical. Electrode material is the key factor of the electric deposition system, which is the key to realize the production mode of "lower energy consumption and higher output".Based on the national "863" project and the Fund Project of National Natural Science Foundation of China, this dissertation presents a new type of Al composite electrode material with a metal ceramic TiB2 interlayer, and which was supported by the National Natural Science Foundation of China.Research on the two aspects of this study which includes substrate material and surface active coating to coated electrode, according to the design and the superposition property of the properties of the composite materials, Ti/Al layered composite material as the matrix material of electrode material which changing the structure and composition of the matrix material to improve the electrochemical performance of the electrode material, and it was studied that the change of Al and Ti thickness ratio was influence on the properties of the electrode material, the key factors that affect the performance of the electrode material was Al, it lays the foundation for the development of new type composite electrode material. The study of surface active coating is aimed at the high cost of the traditional precious metal active coating, it can improve the activity of the coating, reduce the use of rare precious metals, and reduce the cost by the addition of other active element(such as Sn, Ta, Ir and La). To completely get rid of the restriction of the rare precious metal used in the surface active coating, the active coating of the electrode surface is changed to a low cost, high activity and low cost metal oxide According to the excellent comprehensive electrochemical performance of β-PbO2, it reduces the cost of manufacture and use of the electrodes as much as possible under ensuring the electrochemical performance of the electrodes.It was prepared by plasma spraying to the new type Al/TiB2 composites according to the metal ceramic TiB2had wonderful performances in its corrosion resistance and electrical properties on the basis of the previous two parts of the study, β-PbO2 active coating that had high activity and corrosion resistance was prepared on the surface of the new matrix material by electroplating method, it was studied to the effect of material on the electrochemical properties of the electrode materials by analysis of electrochemical performance and composite interface. The various of performance parameters are investigated and compared in the process of the actual electro-deposition of metal Ni to the new type of electrode material in simulated production test (including cell voltage, the amount of on board, current efficiency, power consumption and product quality).The results of study showed that it can improve the corrosion resistance, the distribution of the surface current and the improvement of the electro-catalytic activity by changing the structure of the electrode matrix material. According to the calculation results of the wetting angle and the Gibbs free energy in the process of chemical reaction between Al and TiB2, it is indicated that Al and TiB2 have good wettability(θ≈70°<90°), however, it is impossible to have a chemical reaction process between Al and TiB2(△Gθ>0), the combination of Al and TiB2 can be realized by the diffusion process, and the Al atom can fill the gap of TiB2, which is the foundation of its excellent electrical conductivity.Electrochemical properties of new type electrode materials was tested by electrochemical workstation, those are analyzed to the new electrode materials which include the oxygen-liberating polarization curves(LSV), Tafel corrosion curves(Tafel), cyclic voltammetry curves(CV) and AC impedance spectra(EIS), the results show that the new type of composite electrode material can reduce transfer coefficient of the electrode material (it is two orders of magnitude lower than Ti-based coating electrode) and the exchange current density of surface decreased by 6 orders of magnitude in the corrosion process, so that the corrosion resistance of the electrode material is improved (accelerated lifetime of the Ti group increased by 80%) due to the protection of the metal ceramic TiB2 and the high stability of the surface active coating PbO2 in the process of electrochemical reaction. In the process of oxygen-liberating polarization, the exchange current density is increased by 10 times and the transmission coefficient of the surface is increased by 6.47% on electrode surface to Ti-based coating electrode. The number of voltammetric charge increased on the surface active coating of the electrode(increase 16.14%), the catalytic activity of the coating increased so that the electrochemical reaction rate was accelerated, The electrocatalytic activity is improved to the new type composite electrode material, since the Al matrix has excellent electrical conductivity(the potential change range of the same distance decreased by 85.23%)which lays the foundation for the improvement of the performance of the electrode material.We complete simulation with the productive test in real electrochemical reaction system to the electrode-position of metal Ni, comparison with traditional Pb alloy electrode to all parameters, it shows it which is the new type of Al based composite electrode material for the middle layer of metal ceramic TiB2 can achieve lower cell voltage (can be reduced by 10.34%), improve current efficiency (8.76%), reduce power consumption (24%) and improve the quality of products (impurities Pb content decreased by 73.19%) and other processes. Especially in reducing energy consumption, it can be utilized to produce nearly 2 times more output than conventional Pb alloy electrode, nevertheless the power consumption of the electric energy can be reduced by 340 kWh to Pb alloy electrode. |
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