A novel ironmaking process is under development at the University of Utah to produce iron directly from iron oxides concentrates by the gas-solid flash reaction using gaseous fuels and reductants. This process will reduce energy consumption and minimize carbon dioxide emissions. Having investigated the hydrogen reduction kinetics of magnetite and hematite concentrate particles relevant to the novel flash ironmaking process, the carbon monoxide reduction kinetics of hematite concentrate particles (average particle size 21 lm) was determined in the temperature range 1473 K to 1623 K (1200°C to 1350°C) under various carbon monoxide partial pressures. At 1623 K (1350°C) and residence time 5 seconds, the reduction degree of hematite concentrate particles was more than 90 pct under a pure carbon monoxide. This is slower than reduction by hydrogen but still significant, indicating that CO will contribute to the reduction of hematite concentrate in the flash process. The kinetics of CO reduction separately from hydrogen is important for understanding and analyzing the complex kinetics of hematite reduction by the H 2 + CO mixtures. The nucleation and growth rate equation with the Avrami parameter n = 1.0 adequately described the carbon monoxide reduction kinetics of hematite concentrate particles. The reduction rate is of 1st order with respect to the partial pressure of carbon monoxide and the activation energy of the reaction was 231 kJ/mol, indicating strong temperature dependence. The following complete rate equation was developed that can satisfactorily predict the carbon monoxide reduction kinetics of hematite concentrate particles and is suitable for the design of a flash reactor dX dt ¼ 1:91 Â 10 7 Â e À231000 RT Â pCO À pCO 2 K Â ð1 À XÞ; where X is the fraction of oxygen removed from iron oxide, R is 8.314 J/mol K, T is in K, p is in atm, and t is in seconds.

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For coal powder in southwest of China, sulfur fixing technology of coal powder combustion in this paper has been studied by thermodynamics calculation and experiment. Results show that, the sulfur fixation efficiency of CaO in experiment is highest; when n(CaO)/n(S) ratio equal to 2.0, additive Fe203 enhances the sulfur fixation efficiency of fixing agent CaO. Fe203 is easier to decompound gradually to Fe304 and FeO at the reducing action of C. One side the oxides of iron can catalyze the reaction of sulfur-fixing, on the other hand Fe304 can absorbs S02 to turn to FeS04'

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