Abstract: Demineralization of coal in which a slurry of the coal to be treated is ground in the presence of aqueous acid such as HCl H.sub.2 SO.sub.4 and H.sub.2 CO.sub.3 and then the slurry is subjected to froth flotation in the presence of a gas selected from Cl.sub.2, SO.sub.2, or CO.sub.2.

Abstract: Carbonization of coal in travelling grate furnace with hot gas inlets below the grate. A refractory screen is provided above the grate to provide a flame propagation base for the volatile gases withdrawn from the coal on the grate. The combustion zone above the refractory screen provides radiant heat to vaporize volatiles present in the coal on the grate.The coal to be treated may be in the form of briquettes or an extruded slab. When an extruded slab of slurried coal is used the thermal shock on first entering the carbonization chamber results in the formation of carbon granules.