Jacques Poirier

Investigating the mechanism of phase transformations and migration in olivine at high temperature

A framework is presented to define the formation and migration mechanisms of oxides in olivine during their phase transformations at high temperature. The behaviour of olivine particles has been investigated at 1400 °C at two different residence times: 4 h and 115 h. The structural and vibrational properties of the resulting materials were analysed using both X-ray diffraction (notably, in situ X-ray diffraction) and Raman spectroscopy including its mapping mode. The measurements have shown the migration of magnetite and enstatite from the inner part of olivine particles towards the surface, which results in the alteration of the solid solution and the intergranular reaction of particles. These results contribute to a better knowledge of olivine material science, in particular, in the areas of catalysis, refractories and engineering.

Effect of Slag Impregnation on Macroscopic Deformation of Bauxite‐Based Material

This work aims at studying the volume change of bauxite corroded by a molten slag. Cylindrical samples were prepared by mixing ground bauxite with slag. Optical measurement at high temperature (1450 °C) of deformation with a high-resolution camera has been developed. Image processing allowed for determining the change in diameter of the sample. We showed that the deformation was induced by the precipitation of new expansive crystallised phases observed by SEM-EDS analyses. Adding pellets of the same slag upon the samples allowed to emphasize the effect of the slag amount on the size change. The change in diameter significantly increased in the impregnated area.

Correction: Investigating the mechanism of phase transformations and migration in olivine at high temperature

Correction for ‘Investigating the mechanism of phase transformations and migration in olivine at high temperature’ by R. Michel et al., RSC Adv., 2014, 4, 26645–26652.

Study of Reactive Impregnation and Phase Transformations during the Corrosion of High Alumina Refractories by Al2O3-CaO Slag

Corrosion of refractories results from reactive transport namely, transport of agents and chemical reactions of these agents with impregnated medium. On one hand, the transport involves either diffusion or impregnation depending on the state of the corrosive agents and the microstructure of the host media. On the other hand, chemical reactions may be very numerous and complex. This study focused on the reactive impregnation of Al2O3-CaO slag into porous high alumina refractory.Transport properties of the porous media have been assessed by performing wicking test. Chemical reactions between the solid high alumina skeleton and Al2O3-CaO slag involve successive dissolution/precipitation mechanisms forming aluminates of lime. Contrary to the thermodynamic properties of the binary system, the kinetics of these solid/liquid reactions is not well known. Corrosion tests associated with quenching method, XRD and high temperature XRD were performed for a better understanding of the kinetics.