Method for removing ash from solid carbonaceous material

A method for removing ash from a solid carbon material, which relates to the technical field of removing ash from solid carbonaceous materials; reaction conditions are mild, and ash may be removed more effectively, which may thereby reduce the amount of alkali and water used and increase the treatment amount for solid carbonaceous materials, thus reducing the difficulty and costs in recovering an alkali. The ash removing method comprises: S1) mixing an alkaline sub-molten salt medium and a solid carbonaceous material to be treated, heating so that alkali and ash in the solid carbonaceous material to be treated react in the alkaline sub-molten salt medium, and performing solid-liquid separation on a mixed slurry resulting from the reaction to obtain a first solid product and an alkali treatment solution, wherein in the alkaline sub-molten salt medium, the mass fraction of the alkali is greater than or equal to 50%; S2) using an acid solution to perform acid cleaning treatment on the first solid product, and performing solid-liquid separation again to obtain a second solid product and an acid cleaning solution. Each embodiment is used for removing ash from a solid carbonaceous material.