High‐temperature reduction of iron oxides by solid carbon or carbon dissolved in liquid iron–carbon alloy

Abstract

The reaction between iron oxides and carbon was experimentally studied at temperatures higher than 1473 K employing solid carbon or carbon dissolved in liquid iron as a reducing agent. Iron oxides–carbon composite pellets were submitted to thermogravimetric analysis under inert gas in the range 1473–1623 K; the carbon was in the form of graphite, coke fines and charcoal. It has been determined that the type of carbonaceous material has little effect in the reaction rate at high temperatures. The activation energies obtained varied from 46 to 120 kJ/mol, well below the ones obtained at lower temperature ranges, and it is proposed that at high temperatures the controlling mechanism of the reaction is heat transfer. Composite pellets and fired or cold bonded iron oxide pellets were also added to iron–carbon baths in the temperature range 1573–1912 K. It has been found that up to 1711 K the composite pellets present reaction times significantly shorter than the pure oxide pellets, whereas at higher temperatures the reaction times of both pellets are similar.