Kinetics of MgO chlorination with HCl gas

2019-09-06 00:58:38

The core HCl MgO chlorination

责任者: Ng, K.W.;Kashani-Nejad, S.;Harris, R. 单位: Department of Mining, Metals and Material Engineering, McGill University, Montreal, Que. H3A 2B2, Canada 来源出处: Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science,2005,36(3):405-409 摘要: The kinetics of chlorination of MgO particles with HCl gas in the temperature range from 450°C to 650°C were measured and analyzed in terms of the shrinking core model. The MgO particles were produced by the thermal decomposition of MgOHCl manufactured in-house and were found to have a d50 of 510 nanometers. Over 90 pet of the MgO was converted to MgCl2 within 30 minutes at 650°C. Analysis of the data indicated that the chlorination process was initially controlled by the kinetics of the chemical reaction between MgO and HCl, but as the thickness of the MgCl 2 product layer increased as the chlorination progressed, the rate of chlorination became controlled by the diffusion of HCl through the MgCl 2 ash layer surrounding a MgO core in the particles. A mathematical model that predicted the shrinkage of the MgO core with time was found to be in good agreement with the measurements over the range of temperatures studied. The ash layer thickness for the onset of the diffusion control regime was found to increase linearly with temperature. The apparent rate constant for chlorination in the initial reactioncontrolled regime was well described by the Arrhenius equation: k (m/s) = 0.0787 exp (-7596/T). 关键词: Magnesia;Chlorination;Rate constants;Hydrogen inorganic compounds;Gases;Pyrolysis;Nanostructured materials;Diffusion;Electrolytes;Thermal effects;Mathematical models;Shrinking core model;Diffusion control regime;Ash layer thickness;Chlorination reactions