Release behavior of alkali metals (sodium and potassium) was followed for Barau, Ebenezer and Illinois No. 6 coals at the terminal temperature from 300℃ to 1200℃ with heating rate of 20℃/min and 100℃/min in a nitrogen stream. The release extents of sodium and potassium increased with the increase of terminal temperature and attained to more than 40% and 55%, respectively at 1200℃. Ebenezer and Illinois No.6 showed the release extents of sodium and potassium lower then 15% in the whole temperature range. Change in five fractions of sodium and potassium, H_2O, NH_4Ac, HCI, H_2SO_4 and HF solubles were observed during the pyrolysis of sample coals. Barau contained high extents of H_2O and NH_4Ac solubles of sodium, which decreased with the increase of pyrolysis temperature. On the other hand, H_2O and NH_4Ac solubles of Ebenezer changed to H_2SO_4 and HF solubles with the increase of temperature.
