Abstract: This study investigates the effects of distillation temperature and time on the tin removal rate from ferrophosphorus during vacuum distillation, based on vacuum distillation separation theory.Theoretical analysis demonstrates that the majority of tin could be effectively separated from ferrophosphorus materials by controlling appropriate distillation temperature and vacuum pressure. Taking tin-rich ferrophosphorus materials as the experimental raw materials and a vacuum induction melting furnace as the separation equipment, the vacuum distillation experiments were carried out at a vacuum of 10 Pa to explore the effects of temperature and time on tin separation performance. The experimental results showed that the tin removal rate increased rapidly with the rise of temperature and reached the maximum value above 1873 K, and higher temperatures barely contributed to extra tin removal. At 1823 K, appropriately extending the distillation time was conducive to enhancing the tin removal rate, while extending the distillation time at 1873 K exerted little promoting effect on tin removal. Through process optimization, the optimal distillation process parameters were determined as follows: a vacuum pressure of 10 Pa, distillation temperature of 1873 K, and distillation time of 60 min. Under this condition, the tin removal rate reached 99.6%, and the Sn mass fraction in condensate reached approximately 90.5wt%. The theoretically calculated optimal distillation temperature was 1820 K, which deviated from the experimental optimal value. Such discrepancy was mainly attributed to the reduced activity coefficients caused by impurity elements in the actual system, which endowed the molten system with non-ideal solution characteristics.

Key words: vacuum distillation, tin-containing ferrophosphorus, tin removal rate, distillation temperature, distillation time

摘要： 为研究磷铁中污染锡在真空蒸馏条件下蒸馏温度和蒸馏时间对物料脱锡率的影响，本工作结合真空蒸馏分离理论开展分析。理论计算表明，通过控制蒸馏温度和真空压力可将大部分锡与磷铁物料分离。本研究以含锡较高的磷铁物料为研究对象，以真空感应熔炼炉为真空蒸馏分离设备，在10 Pa真空度下研究了蒸馏温度和蒸馏时间对含锡磷铁分离效果的影响。实验结果表明，随蒸馏温度提高，脱锡率迅速上升，当蒸馏温度超过1873 K时脱锡率达到峰值，继续提高蒸馏温度脱锡率几乎无变化。在1823 K蒸馏温度时，适当延长蒸馏时间有利于提高脱锡率；而在1873 K蒸馏温度下延长蒸馏时间脱锡率提升不明显。经工艺优化得到含锡磷铁最佳蒸馏工艺条件为：在10 Pa真空度下，蒸馏温度1873 K、蒸馏时间60 min时，物料脱锡率可达99.6%，冷凝物中Sn含量约90.5wt%。理论分析表明最佳蒸馏温度为1820 K，与实验结果存在偏差，源于实际体系中杂质元素会导致活度系数降低，使熔体表现出非理想溶液特性。

关键词: 真空蒸馏, 含锡磷铁, 脱锡率, 蒸馏温度, 蒸馏时间