Patent ID: 6319301
Filing Date: 2001-11-20
Classification: C21B,Y02P

Abstract:
Method for the direct reduction of mineral iron inside a vertical reduction furnace with a gravitational load, wherein the reduction gas flows in counter-flow with respect to the material introduced into the furnace, comprising the following steps: feeding mineral iron from above into the furnace, injecting a controlled amount of a first mixture of high temperature gas in a first reducing zone of said furnace, injecting a controlled amount of a second mixture of high temperature gas in a second zone of said furnace, said first and second zones being arranged one above the other, removing burnt gas from an upper part of said furnace, and removing reduced mineral from a lower part of said furnace, preheating at least a part of said burnt gas to a temperature between about 650.degree. and 950.degree., mixing the preheated burnt gas with a reducing gas based on H.sub.2 and CO, in order to produce a mixed gas, and injecting a controlled quantity of at least a hydrocarbon and oxygen into a first part of said mixed gas, so as to increase the temperature of said first part of said mixed gas between about 800.degree. and 1150.degree. C. and form said first mixture of high temperature gas, and injecting a controlled quantity of at least a hydrocarbon and oxygen into a second part of said mixed gas, so as to increase the temperature of said second part of said mixed gas between about 800.degree. and 1150.degree. C. and form said second mixture of high temperature gas.