Various types of coals were subjected to the pyrolysis at 300 and 400 degreesC (mild pyrolysis), and the removal of Hg from coal was determined. The removal efficiency of Hg greatly varied with coal type from 20 to 80%. The removal efficiency was dependent neither on the specific surface area of coal nor on the particle size of coal. The leaching of Hg from coal was tested using sulfur-containing chelating agents such as 3-mercaptopropionic acid (MPA). The Hg leaching efficiency also varied greatly with coal type. There was a good correlation between the degree of %Hg leaching in the MPA leaching and that of %Hg removal in the mild pyrolysis. (C) 2004 Elsevier Ltd. All rights reserved.