Method at melting in a shaft furnace

Abstract

In a method for melting a material in a vertical shaft furnace having an upper portion, a lower combustion zone portion and an intermediate post-burning portion, said upper and lower portions being separated by a restriction and wherein coke is burned and the material melted in said lower combustion zone by introducing a blast of air close to the bottom of the lower combustion zone to produce combustion gases containing CO and/or H.sub.2 S, the improvement which comprises providing a slurry covered coke to said lower combustion zone for combustion and directing the combustion gases resulting from the combustion of said slurry covered coke to said intermediate post-burning portion and post-burning said combustion gases by introducing into said combustion gases a second blast of air at a level above the point of introduction of said first blast of air at which formation of CO normally has ceased and where the temperature of the mixture of combustion gases and air is sufficiently high so that said mixture is self-igniting. Preferably the post-burning portion is effected in a chamber outside the shaft furnace and a portion of the resulting combustion gases is reintroduced into the upper portion.

Dependencies are inferred from the claim text.