Nozzles introduce jet streams of fine-grain fuel and a gasification medium downwardly toward the surface of a slag bath at the bottom of a cylindrical reactor shaft within a vessel to impinge upon the surface of liquid slag which is discharged through a centrally-arranged overflow in the bottom of the vessel. The nozzles are arranged at an angle within a range of 35 DEG to 40 DEG with respect to the horizontal and positioned so that the jet streams impinge upon the surface of the slag at points defined by a plurality of concentric circles with respect to the overflow to circulate and produce a resulting movement of the liquid slag toward the overflow while maintaining a high temperature and homogeneous slag bath. The nozzles are further positioned so that an angle of about 10 DEG is defined between each jet stream and a vertical tangential plane to the concentric circle at the point where the jet stream impinges. A pressure of about 25 atmospheres is maintained within the reactor and the exit velocity of the jet stream from the nozzles is between 20 and 50 meters per second, preferably 40 meters per second.
