Abstract: The primary impurity minerals in microcrystalline graphite include quartz, mica, chlorite, and sulfide minerals (such as pyrite). Current acid leaching purification processes face challenges, including the low solubility of impurities and the occurrence of secondary precipitation. In this study, hydrochloric acid (HCl) and hydrofluoric acid (HF) were used as the primary leaching agents, and ammonium persulfate ((NH₄)₂S₂O₈) was introduced to enhance the oxidative properties of the leaching system, thereby strengthening the purification effect. Acid leaching experiments demonstrated that the fixed carbon content of graphite increased from 98.0% to 98.4% with the addition of ammonium persulfate, indicating a significant improvement in the purification efficiency. Thermodynamic analysis revealed that while pyrite cannot spontaneously react with HF and HCl at ambient temperature, the addition of ammonium persulfate promoted its dissolution. Furthermore, it was found that the reaction of mica and chlorite with HF tended to generate potassium hexafluorosilicate (K₂SiF₆) precipitates. However, the presence of hydrochloric acid in the mixed acid system effectively suppressed the formation of these precipitates to a certain extent, thereby enhancing the purification efficiency. Structural characterization of the purified graphite indicated that the introduction of ammonium persulfate did not adversely affect the surface morphology or the crystalline structure of the microcrystalline graphite.