Abstract: Expandable graphite（EG） was prepared with natural flake graphite from Panzhihua as raw material，with potassium permanganate and hydrogen peroxide as oxidizing agents，and with nitric acid，sulfuric acid，and perchloric acid as intercalation agents.It was found that the suitable expansion temperature was 950 ℃ by experiment，and all the EG were made at this temperature.Results showed that the expansible volume was at 130.97~221.80 mL/g when it made with hydrogen peroxide and sulfuric acid，while it was at 150.65~247.19 mL/g with potassium permanganate and nitric acid.The  expansible volume was even larger than 300 mL/g when it made with potassium permanganate and perchloric acid， after dried for 4~5 h at 50 ℃. X-ray diffraction and scanning electron microscope were used to study its structure and morphology，and results showed that the structure of EG was complete，and it could used for making composite phase change material.

Key words: natural flake graphite, expandable graphite, expansion volume, intercalation agent, oxidant