Reduction vessel for the reduction of metal-oxide-bearing material

Abstract

The invention relates to a reduction vessel ( 1 ) for the reduction of metal-oxide-bearing material, particularly of iron ore, by means of a reduction gas flowing countercurrently to the metal-oxide-bearing material, which reduction vessel ( 1 ) is provided with an inlet ( 5 ) for the metal-oxide-bearing material, an inlet ( 6 ) for the reduction gas, an outlet ( 7 ) for off-gas and an outlet ( 8 ) for reduced material, downstream of which outlet ( 8 ) a lower sealing leg ( 9 ) is connected, a supply line ( 10 ) for a first sealing gas being provided at the lower sealing leg ( 9 ) in order to seal the reduction vessel ( 1 ) against the environment, characterized in that at least one additional supply line ( 12 ) for an additional sealing gas is provided at the lower sealing leg ( 9 ), the additional supply line ( 12 ) being located downstream of the supply line ( 10 ) for the first sealing gas, seen in the direction of flow of the reduced material (FIG. 1 ).

1 . Reduction vessel ( 1 ) for the reduction of metal-oxide-bearing material, particularly of iron ore, by means of a reduction gas flowing countercurrently to the metaloxide-bearing material, which reduction vessel ( 1 ) is provided with an inlet ( 5 ) for the metal-oxide-bearing material, an inlet ( 6 ) for the reduction gas, an outlet ( 7 ) for off-gas and an outlet ( 8 ) for reduced material, downstream of which outlet ( 8 ) a lower sealing leg ( 9 ) is connected, a supply line ( 10 ) for a first sealing gas being provided at the lower sealing leg ( 9 ) in order to seal the reduction vessel ( 1 ) against the environment, 
 characterized in that    at least one additional supply line ( 12 ) for an additional sealing gas is provided at the lower sealing leg ( 9 ), the additional supply line ( 12 ) being located downstream of the supply line ( 10 ) for the first sealing gas, seen in the direction of flow of the reduced material.    
     
     
         2 . Reduction vessel according to    claim 1   , characterized in that the outlet ( 7 ) for off-gas is connected with the lower sealing leg ( 9 ) by means of a line ( 12 ; 16 ) and that a burner ( 17 ) for the combustion of off-gas and a cooling device ( 19 ) for cooling the off-gas combusted in the burner ( 17 ) are provided.  
     
     
         3 . Reduction vessel according to    claim 2   , characterized in that the cooling device ( 19 ) is a heat exchanger or a scrubber.  
     
     
         4 . Reduction vessel according to    claim 2    or    3   , characterized in that a compressor ( 21 ) is provided in the line ( 12 ; 16 ), which is connected downstream of the cooling device ( 19 ).  
     
     
         5 . Reduction vessel as claimed in any of    claims 1    to    4   , characterized in that a vessel ( 2 ) for the metal-oxide-bearing material is connected with the reduction vessel ( 1 ) by means of a line ( 3 ; 4 ) and that at the connecting line ( 3 ; 4 ) a supply line ( 24 ) for a sealing gas for sealing the reduction vessel ( 1 ) against the vessel ( 2 ) for the metaloxide-bearing material is provided.  
     
     
         6 . Reduction vessel according to    claim 5   , characterized in that at least one additional supply line ( 23 ) for an additional sealing gas is provided at the connecting line ( 3 ; 4 ) of the vessel ( 2 ) for the metal-oxide-bearing material to the reduction vessel ( 1 ), which additional supply line ( 23 ) is connected with the supply line ( 12 ) for additional sealing gas to the lower sealing leg ( 9 ).  
     
     
         7 . Process for sealing a reduction vessel ( 1 ) in which metal-oxide-bearing material, particularly iron ore, is reduced by means of a reduction gas flowing countercurrently to the metal-oxide-bearing material and from which reduced material is discharged through an outlet ( 8 ) and through a lower sealing leg ( 9 ) connected downstream of the outlet ( 8 ), a gas that is inert to the chemical reactions occurring in the reduction vessel ( 1 ) being used for sealing the reduction vessel ( 1 ) against the environment and for operating a first gas seal ( 11 ), 
 characterized in that    an additional gas is used for sealing the reduction vessel ( 1 ) against the environment, with which at least one additional gas seal ( 13 ) is operated which is located downstream of the first gas seal ( 11 ), seen in the direction of flow of the reduced material.    
     
     
         8 . Process according to    claim 7   , characterized in that the additional gas is generated from the off-gas of the reduction vessel ( 1 ), which is nearly stoichiometrically combusted and subsequently cooled.  
     
     
         9 . Process according to    claim 8   , characterized in that the off-gas of the reduction vessel ( 1 ) is post-combusted after the nearly stoichiometric combustion and prior to cooling.  
     
     
         10 . Process as claimed in any of    claims 7    to    9   , characterized in that the additional gas is set to an oxygen content of max. 3 volume percent.  
     
     
         11 . Process as claimed in any of    claims 8    to    10   , characterized in that the additional gas is compressed after cooling.  
     
     
         12 . Process as claimed in any of    claims 7    to    11   , characterized in that the metal-oxide-bearing material is charged from a vessel ( 2 ) into the reduction vessel ( 1 ), the reduction vessel ( 1 ) being sealed against the vessel ( 2 ) for the metal-oxide-bearing material by means of a gas that is inert to the chemical reactions occurring in the reduction vessel ( 1 ), with which a gas seal ( 25 ) is operated.  
     
     
         13 . Process according to    claim 12   , characterized in that an additional gas is used for sealing the reduction vessel ( 1 ) against the vessel ( 2 ) for the metal-oxide-bearing material, with which at least one additional gas seal ( 26 ) is operated.