Simultaneous thermal analysis and mass spectrometry were used to determine the combustion characteristics of the original and demineralized Afsin-Elbistan lignite and its char. The major gaseous products evolved were characterized. An integral method was applied for kinetic calculations. The demineralized lignite shows the highest overall reactivity for combustion. A pronounced decrease of the final combustion temperature and activation energy of combustion is observed for the demineralized case. The differences observed in SO2 emissions of the original and demineralized lignite and char are primarily due to the adsorption and/or chemisorption of SO2 by the calcium oxides of the mineral matrix.