The kinetic study on selective chlorination of iron from the ilmenite using chlorine gas and coke was carried out in a static bed. The effects of reaction temperature, chlorine partial pressure, total gas flow rate, and coke content on the reaction rate were investigated. Also, an unreacted shrinkin...
The kinetic study on selective chlorination of iron from the ilmenite using chlorine gas and coke was carried out in a static bed. The effects of reaction temperature, chlorine partial pressure, total gas flow rate, and coke content on the reaction rate were investigated. Also, an unreacted shrinking core model was applied to simulate the iron chlorination rate of ilmenite. In the unreacted shrinking core model, a porous TiO2 product layer appears around the unreacted core and the reactant gas diffuses through the pores of the product layer.
From the experimental result, the iron removal rate was increased with the reaction temperature, and with the amount of coke added. However, if coke was added in excess, the oxygen partial pressure was excessively low, and consequently both Fe and Ti were removed.
The simulated reaction rates were in good agreement with the experimental results. So, the model could be applicable to the iron chlorination reaction of ilmenite. The simulated results showed that the effective diffusion coefficient of chlorine gas, which depends on the pore size, porosity, and tortuosity of the product layer, significantly decreased as the reaction temperature decreased. When 1 g of coke added, and the reaction temperature was 1023 K, the effective diffusion coefficient of chlorine gas was 6.6×10-7 cm2/s at which measured average pore diameter was 53 nm. At 1173 K, the effective diffusion coefficient of chlorine gas at the pore size of 198 nm was 4.5×10-5, which is about 70 times larger than that of at 1023 K. The effective diffusion coefficient significantly changes depending on the reaction temperatures. Consequently, the diffusion resistance through the product layer was dominant at lower reaction temperature, whereas the chemical reaction resistance became more dominant as the reaction temperature increased.
The kinetic study on selective chlorination of iron from the ilmenite using chlorine gas and coke was carried out in a static bed. The effects of reaction temperature, chlorine partial pressure, total gas flow rate, and coke content on the reaction rate were investigated. Also, an unreacted shrinking core model was applied to simulate the iron chlorination rate of ilmenite. In the unreacted shrinking core model, a porous TiO2 product layer appears around the unreacted core and the reactant gas diffuses through the pores of the product layer.
From the experimental result, the iron removal rate was increased with the reaction temperature, and with the amount of coke added. However, if coke was added in excess, the oxygen partial pressure was excessively low, and consequently both Fe and Ti were removed.
The simulated reaction rates were in good agreement with the experimental results. So, the model could be applicable to the iron chlorination reaction of ilmenite. The simulated results showed that the effective diffusion coefficient of chlorine gas, which depends on the pore size, porosity, and tortuosity of the product layer, significantly decreased as the reaction temperature decreased. When 1 g of coke added, and the reaction temperature was 1023 K, the effective diffusion coefficient of chlorine gas was 6.6×10-7 cm2/s at which measured average pore diameter was 53 nm. At 1173 K, the effective diffusion coefficient of chlorine gas at the pore size of 198 nm was 4.5×10-5, which is about 70 times larger than that of at 1023 K. The effective diffusion coefficient significantly changes depending on the reaction temperatures. Consequently, the diffusion resistance through the product layer was dominant at lower reaction temperature, whereas the chemical reaction resistance became more dominant as the reaction temperature increased.
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