Abstract: The effects of particle size，hydrochloric acid concentration，and leaching temperature on the leaching ratios of alu- minum，iron，and calcium ions from activated coarse coal gasification slag were investigated.The leaching mechanism of each ion was also discussed.Results showed that the activated coarse coal gasification slag was a solid solution of gehlenite（2CaO·Al2O3·SiO2） and Fe2O3，which decreased in particle size after the hydrochloric acid leaching.The calcium cation was easier to be leached than aluminum and iron ions and its leaching process fitted the shrinking core model controlled by the chemical reaction.The apparent activation energy of calcium cation was 71.3 kJ/mol.The leaching processes of aluminum and iron ions fitted the Avrami model controlled by the internal diffusion.The apparent activation energy of aluminum and iron ions were 24.7 kJ/mol and 22.5 kJ/mol，respectively. 

Key words: coarse coal gasification slag, leaching mechanism, Avrami model, shrinking core model