基于霍尔-埃鲁特电解法制备铝合金技术研究进展

Production of aluminum alloys in electrolysis cells based on Hall-Héroult process: a review

  • 摘要: 现代霍尔-埃鲁特(H-H)法铝电解槽规模大、工艺成熟, 利用该法电解制备铝基合金具有明显技术和经济优势. 目前国内外研究主要是在现有氟化物熔盐体系中添加多种合金元素氧化物, 合理调节电解质成分和工艺参数, 借助共电沉积和欠电位机制, 成功制备出多种铝基合金, 工业化试验亦有初步成果. 本文综合分析了上述进展及发展前景, 并指出在实现合金组成精准调控、合金产品成分均匀化、电解槽高电流效率运行等方面存在的问题, 旨在为相关研究提供参考.

     

    Abstract: Modern large-scale Hall-Héroult (H-H) aluminum electrolysis cells have super high amperage and a well-developed process technology; thus, they present great technical and economic advantages for the production of Al-based alloys. Compared with the traditional alloy production methods, H-H-based processes have a great potential in improving product quality, simplifying production process, and reducing energy consumption. In this review, the major achievements in the production of various common aluminum alloys, such as Al-RE (rare earth metals), Al-Mg, and Al-Si/Ti alloys using H-H-based processes, were summarized from the domestic and international literature. The main properties of cryolite-based electrolyte systems that determine whether the alloy production can proceed smoothly by H-H process were first discussed based on previous research results. Studies on the electrolyte structure, melting point, and conductivity of the cryolite-based electrolytes with varying compositions were described in details. For producing Al-based alloys, the conventional fluorides electrolytes can be modified by adding various oxides of alloying metals. The electrolysis mechanisms of cathode co-deposition and underpotential deposition are usually utilized with the addition of multiple metals oxides, and the electrolyte composition and processing parameters are appropriately adjusted in H-H-based processes. Moreover, the potential distribution in the interfacial reaction processes during electrolysis for the alloying process in electrolyte is proposed based on the existing electrochemical data. In addition, some industrial trials showed promising results for the future development. At present, these trials, especially for Al-Si and Al-Ti alloys, indicate that the contents of alloying elements can be stabilized within a certain range by adjusting electrolyte compositions, current density, feeding cycle, and other parameters. There are, however, problems associated with the accurate control of alloy compositions, the homogenous quality in bulk alloy products, and the electrolysis cell operation with high current efficiency. Further research is needed to address these problems.

     

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