海绵钛生产蒸馏过程中杂质去除机理和动力学研究

海绵钛真空蒸馏后期5~10%挥发性杂质的去除时间占蒸馏周期的70%，导致蒸馏生产的周期长、能耗高。项目通过研究真空蒸馏过程钛坨温度场分布、传热特性和杂质输运通道结构等因素对镁和氯化镁等挥发性杂质在蒸馏开始阶段的表面蒸馏速率和蒸馏后期的毛细孔内蒸馏速率的影响，研究挥发性杂质在蒸馏过程中的输运特性；利用海绵孔—挥发性杂质界面势函数，建立基于钛坨温度场分布、传热特性和杂质输运通道结构的挥发性杂质蒸馏的热力学和动力学模型，解析挥发性杂质蒸馏动力学的限制性环节，阐明挥发性杂质在蒸馏过程中的物理化学行为；最终依靠建立的热力学和动力学模型阐明挥发性杂质的去除机理，为实现利用Kroll法短流程直接制备高纯海绵钛和蒸馏过程的节能降耗提供理论依据和技术途径。

Removal of last 5~10% of the volatile impurities wastes the 70% of total distillation period in the vacuum distillation process, which was time and energy intensive. Thus, it's difficult to provide theoretical support and control technology in practical production which aims at removing volatile impurities in the greatest degree. The effects of temperature field distribution, heat transfer characteristics and the structures of the impurities transportation corridor of sponge titanium on the surface distillation rate of the volatile impurities such as magnesium and magnesium chloride in the initial stage and distillation rate and in a capillary hole in the final stage will be discussed in the vacuum distillation process. Besides, we inquire the transport characteristics of volatile impurities in the process of distillation. According to the potential function of the interfaces of the sponge-like pores and the impurities, the thermodynamics and dynamics models of volatile impurities distillation will be established, based on the temperature field distribution of sponge titanium, heat transfer characteristics and the structures of impurities transportation channels. Furthermore, the bottlenecks of distillation kinetics in volatile impurities would be analyzed, the physical and chemical behaviors of volatile impurities in distillation process will also be illuminated. Finally, the removal mechanism of volatile impurities is being explored by the thermodynamics and dynamics models. It provides a theoretical basis and technical approach for the realizations of energy conservation and consumption reduction of high-level sponge titanium by using the Kroll method.