Pyritum, a mineral medicine, has been widely used in orthopedics and traumatology in China for nearly 1500 years. Before its use as a drug, it must be air-roasted and vinegar-quenched to produce an effective compound, pyrrhotite (Fe7S8), while reducing harmful substances. However, this process is prone to generating toxic compounds such as sulfur dioxide (SO2) and arsenic trioxide (As2O3). Moreover, processed pyritum sold in China still exhibits significant issues with high levels of arsenic (As) and lead (Pb). This study proposes a green processing method for vacuum roasting pyritum. FactSage software was used to confirm that the vacuum environment facilitates the production of Fe7S8 while effectively preventing oxidation and simplifying the removal of As and Pb. The iron (Fe) content within the temperature range of 600–1000 °C increases from 27.96% to 62.41%. X-Ray Diffraction (XRD) and Mineral Liberation Analyzer (MLA) results indicate a significant transformation of the primary component, pyrite (FeS2), in pyritum into Fe7S8.The optimal processing conditions were determined to be vacuum roasting at 1000 °C for 60 min, resulting in a remarkable removal efficiency of 70.27% for Pb and the complete elimination of As. It can be concluded that vacuum roasting pyritum is a simple, high-stability, environmentally friendly, and clean procedure.