高温电解还原铁技术研究进展及展望

Progress and prospects of high-temperature electrolytic ironmaking

  • 摘要: 传统高炉炼铁流程对焦炭等碳质还原剂依赖程度高,存在流程长、能源消耗和碳排放强度较高等问题. 在钢铁工业低碳转型背景下,以电子替代碳质还原剂的高温电解还原铁技术受到广泛关注. 本综述详细论述了熔融氧化物电解(MOE)法、熔盐电解法以和熔盐电脱氧(FFC)法制备金属铁及铁合金的技术原理、关键影响参数及工业化应用情况等. 重点关注了电解过程熔体结构调控、电极材料创新等研究进展. 从工艺技术、碳排放、能耗以及成本等角度对比了三种高温电解法与传统高炉法炼铁工艺. 三种技术路线分别具有不同的产业化方向:MOE可直接获得液态铁,更适合面向钢铁工业的原生液态铁生产,但仍需解决惰性阳极和槽衬寿命、连续加料与出铁及高温热管理等问题;熔盐电解法更适合高纯、细粒或特殊形貌铁粉的制备,但受含铁物质溶解与传质、电解质稳定性和产品净化的限制;FFC法在固体氧化物直接脱氧及多组元合金粉末制备方面具有优势,现阶段更适合高附加值金属及合金粉末市场. 本文进一步指出,实验室高电流效率和金属化率能否在大尺寸、多电极及长周期连续运行条件下保持,是该领域尚未解决的核心问题. 未来应优先开展跨尺度性能验证、真实铁矿体系和闭路盐循环条件下的全过程评价,并依据产品形态和技术成熟度实施差异化的产业化策略.

     

    Abstract: Conventional blast-furnace ironmaking relies significantly on coke and other carbonaceous reductants and is characterized by a long process chain, high energy consumption, and substantial carbon-emission intensity. To support low-carbon transition in the iron and steel industry, high-temperature electrolytic reduction technologies, which replace carbonaceous reductants with electrons, have garnered increasing attention. This review systematically examines the fundamental principles, key influencing parameters, and industrial development of molten-oxide electrolysis (MOE), molten-salt electrolysis, and molten-salt electro-deoxidation—represented by the Fray–Farthing–Chen process (FFC) Cambridge process—for the production of metallic iron and ferroalloys. Recent advances in melt-structure regulation, electrode-material development, and related process optimizations are emphasized. The abovementioned three high-temperature electrolysis routes, which exhibit distinct industrialization pathways, are compared with conventional blast-furnace ironmaking in terms of process characteristics, carbon emissions, energy consumption, and production costs. MOE can directly produce liquid iron, making it more suitable for the production of primary liquid iron for the bulk steel industry. However, its commercialization is limited by the service life of inert anodes and refractory linings, continuous feeding and tapping, and high-temperature thermal management. Molten-salt electrolysis is more suitable for producing high-purity, fine, or morphology-controlled iron powders; however, its further development is limited by the dissolution and mass transfer of iron-bearing species, electrolyte stability, and downstream product purification. The FFC process is advantageous in the direct electro-deoxidation of solid oxides and the preparation of multicomponent alloy powders; currently, it is preferred in high-value metal and alloy-powder markets. This review further identifies the retention of high laboratory-scale current efficiencies and metallization degrees under large-scale, multielectrode, and long-term continuous operating conditions as a major unresolved challenge. Future studies should prioritize cross-scale performance validation, comprehensive process evaluation using actual iron ores and closed-loop salt-recycling systems, and differentiated commercialization strategies based on product form and technological maturity.

     

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