Experimentation and kinetic modeling of low-temperature oxidation of magnesium particles for the production of energy with low environmental impact

Abstract

Future lack of fossil fuels and global warming stimulate researches on new renewable sources of energy, especially for transportation. With high energy densities, metals appear to be relevant energy carriers. In this study, magnesium powder was considered as a metal fuel for energy production through slow oxidation. Temperature Program Oxidation experiments of magnesium powder were performed using thermogravimetric analyses under four low heating rates (1, 2, 3 and 5 °C min−1). The influence of the particle size was investigated by testing three size fractions (20–50, 50–71 and 71–100 µm). Initial and fully or partially oxidized particles (stopping the reaction at selected conversion rates) were characterized using optical microscopy analyses, which highlighted the different stages of the oxidation mechanism. A three-step kinetic model involving heat transfers was finally proposed to describe the slow oxidation of magnesium and to extract optimal values of the kinetic parameters.