Restrictions for pollutant emissions are getting more stringent these days due to rising environmental concerns over the world. Immense utilization of fossil fuel over past hundred years has been blamed as a major source of pollutant. However, fossil fuels are still considered as a major energy source. Moreover, coal consumption in the future is expected to increase due to rapid industrialization of developing countries. In order to migrate smoothly to new energy source with long-time visions, development environmentally sound process to utilize fossil fuel is essential. As such efforts, removal of mineral matters and modification of low rank coal recently have been attempted and reported. Ultra Clean Coal project in Australia and Hyper Coal (HPC) project in Japan recently have been demonstrated as efficient demineralization process of coal by alkali solution treatment and organic solvent extraction respectively. Successful development of these processes would enable the direct combustion of cleaned coal powder in gas turbine of power plants which will result in both reduction of CO2 by 20% and increase of efficiency up to 48%. However, both the UCC and HPC also have obstacles for practical operation. The treated coal in the UCC process still contains 0.1 to 0.5% of ash and 60ppm of alkali metals. The ash and alkali metals in the treated coal by thermal extraction (at 360°C and 1MPa) with organic solvent is less than 200ppm. The remained alkali metals in treated coal would cause corrosion on internal parts of the turbine. Therefore, a subsequent process is still needed to reduce alkali metal contents to less than 0.5ppm, which is the currently acceptable level for introduction to gas turbine. It seems that ion exchange method would fit the most for removing trace of alkali metals and the successful development of a feasible ion exchange process would expedite realization of the coal modification process. In this study, removal of alkali metals using ion exchangers was attempted. In order to maximize overall efficiency of the coal modification process, ion exchange must occur in the same condition of thermal extraction(at 360°C and 1MPa). In addition, organic solvents, such as NMP (N-methyl-2-pyrrolidone), are supposed to be in exchange medium. Therefore, inorganic ion exchangers, which can endure such rough condition, were prepared and tested.