Abstract: A furnace is provided for burning soila organic fuels including highly volatile organic fuels. A combustion chamber with an ash hopper has a slot mouth opening defined by slopes of the walls of the combustion chamber. A burner is disposed beneath the ash hopper mouth opening and extends across its entire width. A bottom blast inlet device generates a turbulent zone in the lower region of the combustion chamber. A duct is further provided for injecting a sulfur-absorbent material into the furnace chamber. The duct is disposed between the burner and the ash chamber and defines a longitudinal axis which traverses the turbulent zone. Preferably, the burner is tilted downwardly and is disposed on a wall in common with the sulfur-absorbent induction duct. The proportion of the sulfur-absorbent materials in the fuel mixture is in the range of 10% to 100% by mass.