A furnace comprises an upper frame and a lower frame, which form a cooling system loop for the furnace chamber and are connected to one another by pipes that run along the outer side of the wall of the furnace chamber without coming into contact therewith. Inside the furnace, a brick pipe is suspended from the frame of the upper frame with the aid of tubes of the cooling system. A space for the accumulation of flue gases is disposed on the upper frame, above the furnace chamber, and is connected to the furnace, via a flue gas pipe running along the outer side of the furnace, by means of a rectangular pipe welded to the lower frame. Outside of the layers of semi-coke and coke burning vertically throughout their full height, flue gases penetrating through the vertical layers are combusted and turned into furnace gases; the flue gases are separated from the furnace gases; viscous plastic masses create resistance to the penetration of the flue gases into the furnace and said gases are directed along a separate path from the furnace gases; the flue gases enter the space for the accumulation of flue gases as a result of a difference in temperature between the flue gases and the air in the space for the accumulation of flue gases.