Phase Transformation of Diatomite during Magnesiothermic Reduction Process

Abstract

In this study the phase behavior of diatomite during magnesiothermic reduction process was investigated. Two packing routes were adopted to estimate the reduction effectiveness at a low reaction temperature of 650 °C for 2h. The phase and microstructure evolution of diatomite were investigated by XRD, SEM, EDS. The results show that diatomite was sucessessfully reduced by the magnesium vapor and reaction products were Si, MgO, and Mg2Si when the raw diatomite was blended with Mg powder. Mg2Si and MgO were alternatively and incompletely dissolved after being immersed in a 1 M HCl solution for 6 h. Meanwhile, the reactant molar ratio had an important influence on products when the raw diatomite was separated with the Mg powder. A small amount of diatomite was reacted to generate MgO and Mg2Si as the molar ratio of Mg and diatomite was 2:1. By contrast, with the molar ratio increasing to be 10:1, diatomite was completely reacted to be Mg2Si and MgO.