GB1055819A - Reduction of iron ore - Google Patents

Abstract

<PICT:1055819/C4-C5/1> In a process for reducing iron ore, a portion of the combustible effluent gases from the reducing zone 24 is passed, in contact with externally added steam 74 and a hydrocarbon, preferably methane, through a reforming zone 70 which may include a catalyst, and an amount of water equal to the externally added steam is removed, e.g. by a condenser-cooler 18 and separator 21, from the gas, which is then passed through the reducing zone. The net reactants are thus only the ore, which provides the oxygen for the reformation, and the hydrocarbon. The hydrocarbon, which may be liquid or gaseous, is introduced in stoichiometric proportions relative to the carbon dioxide and water in the portion of the recycle gases, and additional water may be removed from the recycle gases before the steam and hydrocarbon are added, see Fig. 1 (not shown). The portion of the gases not recycled may be used as fuel for the reformer. In a modification, Fig. 2 (not shown) heated solids, which may be catalytic, are circulated between a solids heating zone and the reformer, being entrained therebetween in a stream of recycle gases, hydrocarbon, and added steam, the heater being heated by burning the non-recycled gas portion from the reducer with air and fuel. In Fig. 3, reformation and solids heating take place in transfer line heaters 70, 77 respectively which, with alternate cyclone separators 75, 72, form a circuit for the solids. Flue gases from the heater 77 are delivered by a line 78 to an iron ore preheater 79. Three specific examples, all employing methane, are described.ALSO:<PICT:1055819/C6-C7/1> In a process for reducing iron ore, a portion of the combustible effluent gases from the reducing zone 24 is passed, in contact with externally added steam 74 and a hydrocarbon, preferably methane, through a reforming zone 70 which may include a catalyst, and an amount of water equal to the externally added steam is removed, e.g. by a condensercooler 18 and separator 21, from the gas, which is then passed through the reducing zone. The net reactants are thus only the ore, which provides the oxygen for the reformation, and the hydrocarbon. The hydrocarbon, which may be liquid or gaseous, is introduced in stoichiometric proportions relative to the carbon dioxide and water in the portion of the recycle gases, and additional water may be removed from the recycle gases before the steam and hydrocarbon are added, see Fig. 1 (not shown). The portion of the gases not recycled may be used as fuel for the reformer. In a modification Fig. 2 (not shown) heated solids, which may be catalytic, are circulated between a solids heating zone and the reformer, being entrained therebetween in a stream of recycle gases, hydrocarbon, and added steam, the heater being heated by burning the non-recycled gas portion from the reducer with air and fuel. In Fig. 3, reformation and solids heating take place in transfer line heaters 70, 77 respectively which with alternate cyclone separators 75, 72, form a circuit for the solids. Flue gases from the heater 77 are delivered by a line 78 to an iron ore pre-heater 79. Three specific examples, all employing methane, are described.