Possibility of obtaining magnesium titanate by mechanochemical process in a high-energy vibro mill

Abstract

In order to investigate the possibility of obtaining magnesium titanate, oxides of magnesium and titanium were mechanochemically activated. Mechanical activation was performed for 1000 min in a high-energy vibro mill (engine power is 0.8 kV). The optimal amount of powder activated in the mill is 50-100 g, so according to the stoichiometric calculation, the composition of the starting mixture was 20.2 g (0.5 mol) MgO and 39.9 g (0.5). mol) TiO2. X-ray diffraction analysis of samples taken from the reaction system was performed after 60, 180, 330 and 1000 min of mechanical activation. Atomic absorption spectrophotometry was used to analyze the current chemical composition of the system, depending on the time of activation. Based on the results of X - ray diffraction analysis, it can be concluded that the greatest changes in the system occurred at the very beginning of mechanical activation due to disruption of the crystal structure of the initial components. X-ray diffraction analysis of the sample after 1000 min of activation showed complete amorphization of the mixture, but no diffraction maxima characteristic of magnesium titanate was identified. Therefore, the mechanical activation experiments were stopped. The fact is that the invested energy was not enough to overcome the energy barrier for the formation of a new chemical compound - magnesium titanate. The inability to synthesize magnesium titanate is explained by the low negative Gibbs energy value of -25.8 kJ / mol (despite the theoretical possibility that the reaction will occur), as well as the amount of mechanical energy that entered the system during activation that is insufficient to obtain the reaction product. Although the synthesis of MgTiO3 has not been achieved, significant results have been obtained that identify models for further research into the possibility of mechanochemical reactions of alkaline earth metals and titanium dioxide.