Abstract: A process for demineralizing coal includes the steps of forming a slurry of coal particles in an alkali solution, the slurry containing 10-30% by weight coal, maintaining the slurry at a temperature of 150-250° C. under a pressure sufficient to prevent boiling, separating the slurry into an alkalized coal and a spent alkali leachant, forming an acidified slurry of the alkalized coal, the acidified slurry having a pH of 0.5-1.5, separating the acidified slurry into a coal- containing fraction and a substantially liquid fraction, subjecting the coal-containing fraction to a washing step, particularly a hydrothermal washing step, in which the coal-containing fraction is mixed with water and a polar organic solvent or water and an organic acid to form a mixture and separating the coal from the mixture. The demineralized coal has an ash content of from 0.01-0.2% by weight and can be used a feed to a gas turbine.