Thermogravimetric Study of Porous Forsterite Synthesis by Hydromagnesite and Silica Gel Chlorination

Abstract

A novel pyrometallurgical process for the synthesis of porous forsterite by calcination in chlorine of a mixture containing hydromagnesite and silica gel was developed. The aim of this work was to produce porous forsterite at low temperatures and short reaction times. Effects of temperature, reaction time and chlorine on the synthesis reaction were studied. Also, the reaction mechanism involved in the process was investigated. Isothermal and non-isothermal chlorination assays were carried out in a thermogravimetric equipment designed to work in corrosive atmospheres. Reagents and products were analyzed by thermogravimetry (TG) and X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2 adsorption–desorption isotherm (BET). The results showed that forsterite was obtained at 700 ∘C with a mesoporous structure and a specific surface area of 16.8 m2/g. Furthermore, it was observed that the presence of chlorine favored the decomposition of hydromagnesite.