Magnesium (Mg) alloys are widely used lightweight structural materials for automobiles and help reduce carbon emissions. However, their use increases the production of Mg alloy scrap, which is recycled at a much lower rate than aluminum, and its greater complexity poses challenges to existing recycling processes. Although vacuum distillation can be used to recycle Mg alloy scrap, this requires optimizing and maximizing metal recirculation, but there has been no thermodynamic analysis of this process. In this study, the feasibility and controllability of separating inclusions and 23 metal impurities were evaluated, and their distribution and removal limits were quantified. Thermodynamic analyses and experimental results showed that inclusions and impurity metals of separation coefficient lgβ_i ≤ -5, including Cu, Fe, Co, and Ni below 0.001 ppm, could be removed from the matrix. All Zn entered the recycled Mg, while impurities with -1 < lgβ_i < -5 such as Li, Ca, and Mn severely affected the purity of the recycled Mg during the later stage of distillation. Therefore, an optimization strategy for vacuum distillation recycling: lower temperatures and higher system pressures for Zn separation in the early stage, and the early termination of the recovery process in the later stage or a continuous supply of raw melt can also prevent contamination during recycling. The alloying elements Al and Zn in Mg alloy scrap can be further recovered and purified by vacuum distillation when economically feasible, to maximize the recycling of metal resources.

镁合金是广泛应用于汽车的轻质结构材料，有助于减少碳排放。然而，它们的使用增加了镁合金废料的产量，镁合金废料的回收率比铝低得多，而且其更复杂的情况对现有的回收工艺提出了挑战。虽然真空蒸馏可用于回收镁合金废料，但这需要优化和最大化金属再循环，但尚未对该过程进行热力学分析。本研究评估了分离夹杂物和23种金属杂质的可行性和可控性，并量化了它们的分布和去除限度。热力学分析和实验结果表明，可以从基体中去除分离系数lg β _{i ≤ -5的夹杂物和杂质金属，包括0.001 ppm以下的Cu、Fe、Co和Ni。}Zn全部进入回收镁中，而-1 < lg β _i < -5的杂质如Li、Ca、Mn在精馏后期严重影响回收镁的纯度。因此，真空精馏回收的优化策略：前期较低的温度和较高的系统压力进行锌分离，后期提前终止回收过程或连续供应原料熔体也可以防止回收过程中的污染。在经济可行的情况下，镁合金废料中的合金元素Al和Zn可以通过真空蒸馏进一步回收和提纯，最大限度地回收金属资源。