The chemical changes produced as a result of the interaction of molten salts with mineral components of a semianthracite char (AC) at 873 K in N-2 are investigated. AC samples were treated with the LiCl/KCl eutectic mixture. Generally, a metal oxide (CaO, MgO, FeO, CoO, NiO, Cu2O, or ZnO) was added to the alkali metal chlorides. After the treatments of AC, the residual solid mass was washed with distilled water and oven-dried. The resultant samples were analyzed by X-ray diffraction. The degree of chemical interaction with the inorganic fraction of AC depended on the composition of the molten salts. The solvent itself, owing to the action of Li+ ions, significantly interacted with mineral components of AC. It also occurred for basic oxides such as CaO and for metal oxides as MgO containing a small metal ion.