The effect of mineral matter in char on NO-char reaction in the presence of SO2 was studied by temperature programmed reaction and isothermal experiments. Three coals with different ranks and their demineralized samples were pyrolyzed in N-2 at 900 degreesC to prepare the chars. Different kinds of metals were loaded on the demineralized chars to compare their catalytic effect on NO conversion during NO-char reaction. The results show that the effect of mineral matter is closely related to the content of catalytically active components. More catalytically active components in mineral matter in the char, higher catalytic activity for NO-char reaction. While the inert components, such as Al2O3 and Si2O3, will abate the NO conversion. Besides the catalytic effect of active mineral matter, the reactivity of the char is another important factor to affect the NO conversion during NO-char reaction. With increasing coal rank, the resultant char shows lower activity for reduction of NO. The effect Of SO2 On the NO-char reaction is changed with temperature. At higher temperatures NO conversion is further enhanced by the reaction of NO-SO2 and the increase in the amount of active sites due to the release Of SO2 chemisorbed on the char surface. (C) 2003 Elsevier Ltd. All rights reserved.