Abstract: This study mainly investigated the effect of the common acid leaching process on coal （Tongchuan high sulfur coal） characteristics. Several acid solutions were used in chemical leaching process. Organic and inorganic characteristics, thermochemical and kinetic analysis were carried out in the research. It was found that nitric acid easilyreacted with coal organic macromolecules and decomposed them into smaller molecules. The GC-MS analysis also showed that the nitric acid fractured instable coal macromolecular structure more easily compared to other acids. Nitric acid could react with sulfur and iron containing material to form acid soluble substances. Most acid solutions could significantly reduce the content of sodium, calcium and magnesium. However, hydrofluoric acid could effectively reduce silicon, aluminum and potassium. Hydrofluoric acid leaching process caused the activation energy of coal becoming higher than raw coal. While nitric acid, nitric acid and hydrochloric acid mixed leaching process caused coal sample reaction activation energy decreasing obviously；these suggested that the two coal samples after acid leaching are more likely to pyrolyze and combust.

Key words: high sulfur coal, acid leaching, demineralization and desulfurization, coal characteristic, dynamics analysis