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The reaction kinetics of carbon reduction of silica were investigated using thermodynamic concepts and by fitting to relevant models the experimental data obtained for this reduction using a thermogravimetric unit in the temperature range of 1566 to 1933 K. The results show that the only way to produce SiC in this reduction is the reaction of Si, SiO, or SiO2 at the surface or by diffusion of SiO inside the carbon particles while CO and CO2 have no direct effect on the process. The controlling step of this reduction at temperatures lower than 1750 K is the chemical gas–solid or solid–solid reaction at the surface of the carbon particles, while at higher temperatures, the rate of SiO diffusing inside the carbon particles controls the rate of this reduction.

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In the present study, the reduction of in-flight particles of iron ore concentrate by carbon monoxide has been investigated. A mathematical model was developed for simulating the motion of particles in a CO-Ar gaseous mixture within the reactor. Pre-designed experiments were carried out in a fabricated experimental set-up for validating the model. Excellent agreement between the model predictions and the experimental data approved the accuracy of the model. The nucleation and growth model and the fminsearch optimising method were used for investigating the reaction kinetics. The following equation was obtained relevant to CO reduction of the magnetite concentrate particles:[−Ln(1 − X )] 1/0.56 = 1.632 × 10 −3 d −1.637 P C 2.216 CO exp( − 2.196 × 10 5 /RT)t

In this study, hydrogen reduction of in-flight fine particles of magnetite ore concentrate at constant heat flux condition has been investigated, experimentally and numerically. A 3D turbulent mathematical model was developed to simulate the dynamic motion of these particles and also progress of the reaction. An experimental set-up was made up to evaluate the simulation. The fabricated set-up contains a vertical furnace, a ceramic tube and a handmade powder feeder. There was an excellent agreement between the prediction results and the experimental data. Our simulation and also the experimental data showed a large fraction of the inlet particles traps in the reactor. This is an important issue, should be solved in an industrial scale of the process.

In this study, the reaction kinetics of carbon monoxide reduction of magnetite ore concentrate in the temperature range of 973-1173 K (700-900°C) has been investigated using the thermalgravimetric analysis. Various methods were used to obtain the governing mechanism and reaction rate constant of this reaction. It was observed that the sintering phenomenon affects the concentrate particles' reduction at temperatures higher than 1173 K (900°C). CO reduction of magnetite concentrate to pure iron or iron carbide occurred as a single-step reaction. The first-order reaction model and diffusion models are two important mechanisms for this reaction in the operating temperature range. The following equation is the result of our research work relevant to carbon monoxide reduction of the magnetite concentrate particles in order to predict the progress of the reduction reaction (with R 2 about 0.98):1/1.078 = 3.27 × 10 −3 d −1.871 P C 2.738 CO exp( − 2.438 × 10 5 /RT)t ARTICLE HISTORY

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