Verfahren zur Direktreduktion von Eisenoxide enthaltenden Stoffen

摘要

So as to achieve the most thorough reduction and carburisation to produce Fe3C in a relatively short time and relatively economically, a two-stage treatment in fluidised beds is carried out. The first stage is carried out in a circulating fluidised bed system, the hourly circulation of solids being at least five times the weight of solid present in the fluidised bed reactor, and the greater part of the iron content of the charge being prereduced. The remaining reduction and the partial or complete conversion into Fe3C are carried out in the second stage in a classical fluidised bed. From the off-gas of the circulating fluidised bed, water is condensed, the gas is refreshed (replenished) by the addition of reducing gases and is heated to the temperature required for the process. A portion of the heated circulating gas is passed into the classical fluidised bed, as a fluidising gas, the other portion of the circulating gas being passed, as the fluidising gas, into the fluidised bed reactor of the circulating fluidised bed. The off-gas of the classical fluidised bed is passed, as the secondary gas, into the fluidised bed reactor of the circulating fluidised bed.