Arrangement and process for the reduction of metal-oxide-bearing material

Abstract

Arrangement for the reduction of metal-oxide-bearing material, particularly of iron ore, with a reduction vessel in which the metal-oxide-bearing material is reduced in counterflow with reduction gas and which is provided with an inlet for metal-oxide-bearing material, an inlet for reduction gas, an outlet for off-gas and an outlet for reduced material, a vessel for metal-oxide-bearing material, which is connected with the reduction vessel by means of a line and a first supply line for a sealing gas which serves to seal the reduction vessel against the vessel, which first supply line is provided at the connecting line between the vessel and the reduction vessel, characterized in that at least one additional supply line for a sealing gas is provided at the connecting line, which additional supply line is located between the first supply line and the vessel.

1 . Arrangement for the reduction of metal-oxide-bearing material, particularly of iron ore, with a reduction vessel ( 1 ) in which the metal-oxide-bearing material is reduced in counterflow with reduction gas and which is provided with an inlet ( 2 ) for metal-oxide-bearing material, an inlet ( 3 ) for reduction gas, an outlet ( 4 ) for off-gas and an outlet ( 5 ) for reduced material, a vessel ( 6 ) for metal-oxide-bearing material which is connected with the reduction vessel ( 1 ) by means of a line ( 7 ; 8 ) and a first supply line ( 10 ) for a sealing gas in order to seal the reduction vessel ( 1 ) against the vessel ( 6 ), which first supply line ( 10 ) is provided at the connecting line ( 7 ; 8 ) between the vessel ( 6 ) and the reduction vessel ( 1 ), 
 characterized in that    at least one additional supply line ( 13 ; 23 ) for a sealing gas is provided at the connecting line ( 7 ; 8 ), which additional supply line ( 13 ; 23 ) is located between the first supply line ( 10 ) and the vessel ( 6 ).    
     
     
         2 . Arrangement according to    claim 1   , characterized in that the connecting line ( 7 ; 8 ) which connects the vessel ( 6 ) with the reduction vessel ( 1 ) comprises a sealing leg ( 7 ) and downpipes ( 8 ), the supply lines ( 13 ; 23 ) for sealing gas being provided at the sealing leg ( 7 ).  
     
     
         3 . Arrangement according to    claim 2   , characterized in that the outlet ( 4 ) for off-gas at the reduction vessel ( 1 ) is connected with the sealing leg ( 7 ) by means of a line ( 9 ; 13 ) and that a burner ( 11 ) for off-gas combustion and a cooling device ( 17 ) for cooling the off-gas combusted in the burner are provided.  
     
     
         4 . Arrangement according to    claim 3   , characterized in that the cooling device ( 17 ) is a heat exchanger or a scrubber.  
     
     
         5 . Arrangement according to    claim 3    or    4   , characterized in that a compressor ( 12 a) is provided in the line ( 9 ; 13 ), which is connected downstream of the cooling device ( 17 ).  
     
     
         6 . Arrangement as claimed in any or several of    claims 1    to    5   , characterized in that an additional sealing leg ( 15 ) is provided at the reduction vessel ( 1 ), which is located at the lower end of the reduction vessel ( 1 ), and that at least two additional supply lines ( 11 ; 14 ) for sealing gas are provided at the sealing leg ( 15 ).  
     
     
         7 . Arrangement according to    claim 6   , characterized in that one of the supply lines ( 14 ) for sealing gas is connected with the first supply line ( 13 ).  
     
     
         8 . Arrangement according to    claim 6   , characterized in that a cooling device ( 22 ) is provided in the supply line ( 14 ).  
     
     
         9 . Process for the reduction of metal-oxide-bearing material, particularly of iron ore, with reduction gas in a reduction vessel ( 1 ), the metal-oxide-bearing material being charged from a vessel ( 6 ) into the reduction vessel ( 1 ) and conveyed through the latter in counterflow to the reduction gas, wherein the reduction vessel ( 1 ) is sealed against the vessel ( 6 ) by means of -a first gas seal ( 10 ), which is operated with a first gas that is inert to the reduction of the metal-oxide-bearing material, 
 characterized in that    at least one additional gas seal ( 13 ; 23 ) which is located between the first gas seal ( 10 ) and the vessel ( 6 ) and which is operated with an additional gas.    
     
     
         10 . Process according to    claim 9   , characterized in that the at least one additional gas seal ( 13 ; 23 ) is operated with an oxygenous gas.  
     
     
         11 . Process according to    claim 10   , characterized in that air is used as oxygenous gas.  
     
     
         12 . Process according to    claim 9   , characterized in that off-gas from the reduction vessel is used as gas for the at least one additional gas seal.  
     
     
         13 . Process according to    claim 12   , characterized in that the off-gas is treated in order to reduce the oxygen content, particularly combusted, before it is used as sealing gas.  
     
     
         14 . Process according to    claim 13   , characterized in that the gas is cooled after combustion.  
     
     
         15 . Process as claimed in one or several of    claims 9    to    14   , characterized in that at least two gas seals ( 11 ; 14 ) are also provided at the lower end of the reduction vessel ( 1 ), which are operated with off-gas or inert gas.  
     
     
         16 . Process according to    claim 10   , characterized in that the off-gas used as sealing gas has an oxygen content of max. 3 volume percent.