Study of the Reaction Stages and Kinetics of the Europium Oxide Carbochlorination

POMIRO F.; FOUGA G. G.; GAVIRÍA J.P.; BOHÉ A. E.

METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE

SPRINGER

Lugar: Berlin; Año: 2014

1073-5615

The europium oxide (Eu2O3(s)) chlorination reaction with sucrose carbon was studied by thermogravimetry between room temperature to 950 °C. The non-isothermal thermogravimetry showed that the reaction consists of three stages, their stoichiometries were studied. The product of the first of them was europium oxychloride and it showed independence of the reaction kinetics with the carbon content. Subsequently, in the second stage, the EuOCl(s) was carbochlorinated with formation of EuCl3(l) and its evaporation is observed in the third stage. The analysis by Fourier Transform Infrared spectroscopy of gaseous species showed that the reaction at second stage occur with formation of CO2(g) and CO(g). Reactants and products were analyzed by X-Ray Diffraction, Scanning Electron Microscopy and Wavelength Dispersive X-Ray Fluorescence Spectroscopy. The influence of carbon content, total flow rate, sample initial mass, chlorine partial pressure and temperature was evaluated. The second stage kinetics was analyzed and it showed an anomalous behavior due to generation of chlorine radicals during interaction of Cl2(g) and Carbon. It was found that the reaction rate at 660 °C was proportional to a potential function of the chlorine partial pressure whose exponent is 0.56. The conversion curves were analyzed with the Avrami-Erofeev model and it was obtained an activation energy of 154 ± 5 kJ·mol-1.