Sn ash recycling is an industry with positive development prospects, as it provides better-protected resources, promotes sustainable development, and lays a solid foundation for future development. In this study, an innovative vacuum carbothermal reduction-directional condensation process was developed. The thermodynamic analysis results indicated that the initial reaction pressure and temperature for the carbothermal reduction of the system was 1–10 Pa and 998–1063 K, respectively. The saturation vapor pressure, separation coefficient, and condensation temperature of Sn, Pb, and Zn in the reduced products differed significantly, and their separation could be achieved by controlling the volatilization and condensation temperatures. A single-factor experiment investigated the effects of carbon ratio, temperature, and time on the reduction efficiency, direct yield, and recovery rate. The optimal experimental conditions were the ratio of MeO to C of 4:1, temperature of 1373 K, and time of 120 min. Sn, Pb, and Zn products were obtained at different positions. This process shortens the traditional process, reduces the reduction cost of Sn, and enables the implementation of the process, making it environmentally friendly.

中文翻译：

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从锡灰中回收有价金属的新方法：真空碳热还原-定向冷凝

锡灰回收是一个具有良好发展前景的产业，它可以更好地保护资源，促进可持续发展，为未来发展奠定坚实的基础。在这项研究中，开发了一种创新的真空碳热还原定向冷凝工艺。热力学分析结果表明，体系碳热还原的初始反应压力和温度分别为1~10 Pa和998~1063 K。还原产物中Sn、Pb、Zn的饱和蒸气压、分离系数和冷凝温度差异较大，通过控制挥发和冷凝温度可实现它们的分离。通过单因素实验考察了碳比、温度和时间对还原效率、直接产率和回收率的影响。最佳实验条件为MeO与C的比例为4:1、温度1373 K、时间120 min。在不同位置获得了 Sn、Pb 和 Zn 产物。该工艺缩短了传统工艺流程，降低了Sn的还原成本，并使工艺得以实施，对环境友好。