Hydrothermal-treatment was applied to Victorian brown coal as pretreatment of liquefaction. Contents of both metal and carboxyl group in the coal were reduced effectively by this treatment. The coal particles in the water slurry were recovered by oil agglomeration using liquefaction solvent. It was found that the viscosity of the hydrothermal-treated-coal-solvent slurry was much lower than that of a usual coal-solvent slurry.
