Abstract
The kinetics and mechanism of the chloride volatilization of CuO by HCL-Ar mixture gas were investigated using thermogravimetric analysis under the various chloridizing conditions. The results obtained are summarized as follows.
(1) The overall reaction products were gaseous and liquid cuprous chloride within the temperature range of 600 to 900°C. The rate of chlorination was controlled by the two processes; one is the diffusion of HCL gas through the gas film boundary layer and the other is the vaporization of Cu2Cl2(l) at the surface of the sample, and it was found that they play a major role in controlling the reaction of chlorination.
(2) In the diffusion-controlled zone, the rate of chlorination was affected significantly by the partial pressure of HCL and the gas flow rate. However, it was scarcely affected in the vaporization-controlled zone.
(3) The activation energy obtained from the relation between the rate of chlorination and temperature was found to be 3.0 kcal per mol for the diffusion-controlled zone and 20.6 kcal per mol for the vaporization-controlled zone, respectively.
(4) The phenomena of weight increase and parabolic weight loss were observed in the initial reaction stage of the vaporization-controlled zone under the various chloridizing conditions. These phenomena may be explained by the rate equation which considered the mechanism of nuclear formation and growth of Cu2Cl2(l).
