Investigation On Direct Reducing Iron Process In A Reaction Cylinder

Based on the production process of sponge iron in tunnel kiln in reaction pot , reduction kinetics , production efficiency improvement of sponge iron and desulfurization and dephosphorization behavior in reduction process were sdudied.The results showed that rate controlling step in direct reducing process is carbon gasification reaction. Based on laboratory study in direct reducing kinetics, a kinetics model of char-disappearing core was set up ,velocity equation was deduced, and the kinetics model was verified by experiment data.In DIR inducing process in reaction pot, production efficiency of sponge iron could be improved by pressing iron concentrate powder and decreasing particle size of char reductant powder.Effects of temperature, time, desulfurizer type (lime, calcium carbonate and dolomite) and dosage on desulfurizing rate were investigated. It is concluded that in the same reacting time, desulfurizing efficiency increased with increasing of temperature and dosage of desulfurizer. Lime had the better desulfurization effect than the other two.Effects of reducing temperature and lime proportion in iron concentrate powder on dephosphorizing behavior in direct reducing process were investigated. The results showed that under the basic conditions of direct reducing process in reactor, the phosphorous in raw material was reduced completelly. The activity coefficient of phosphorous greatly decreased due to the reaction of phosphorous, reducing products of phosphorite, with ferrous and forming Fe3P, which made the reducing reaction go fully towards the right directly.2Ca₃(PO₄)₂+3SiO₂+10C+12Fe=3(2CaO·SiO₂)+10CO+4Fe₃PThe research work provides basic information and theoretical foundation for practical application in direct reducing process of tunnel kiln, which shows a applied perspective in fabrication of sponge iron...