Masaki Kobayashi1, Yasuaki Ueda2 and Fumio Noguchi2
1Toshiba Tungaloy Co., Ltd., Kawasaki
CuO pellet is chloridized with HCl-Ar mixture gas in the temperature range of 600 to 900°C and the rate of chlorination was measured by the thermobalance. On the other hand, the reaction process was analyzed by using the mass transfer model which was considered the controll mechanism of chloride volatilization. The experimental results were compared with the calculated values from the mass transfer models. The results obtained are summarized as follows.
(1) Under the small gas velocity and the low HCl partial pressure, the reaction of chlorination is controlled by transport of HCl through the gas film boundary layer at the surface of the sample. Calculated rate from the product of HCl partial pressure and the gas velocity agreed well with the results obtained experimentally.
(2) However, the reaction is controlled by the diffusion of HCl gas with an increase of chloridizing temperature. The experimental results could be analyzed by using the model which was considered only the forced convection.
(3) At the high HCl partical pressure and the large gas velocity, the rate is controlled by the vaporization of Cu2Cl2 (1). The rate was calculated by the mass transfer equation which was considered the forced convection and the natural convection of Cu3Cl3 (g). Activation energies obtained by each models agreed very well with the values obtained from experimental data. Calculated values were given 2.8 kcal/mol in the diffusion controlling step, 21.3 kcal/mol (at the forced convection) and 23.2 kcal/mol (at the natural convection) in the vaporization controlling step of Cu2Cl2 (1).
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