Abstract
Thermodynamic studies of the Mg-Te-O system have significant importance in improving Te recovery from pyrometallurgical processes and materials preparation in related fields. Ternary compounds, Mg3TeO6, Mg2Te3O8, MgTe2O5 and MgTe6O13, in the Mg-Te-O system have been synthesized in the present study, and their decomposition behaviors at various atmospheric conditions have been experimentally studied with the TGA-DSC technique. Obtained results showed that: 1) Mg3TeO6 started to decompose to MgO, TeO2, and O2 at 1255.9 °C in the carrying gas of 20% O2 - 80% Ar, and the initial decomposition temperature decreased along with decreasing oxygen concentration in the gas; 2) Mg2Te3O8 decomposed to MgO and TeO2, and when the O2 was rich in the gas, Mg3TeO6 was also found in the product. The initial decomposition temperature of Mg2Te3O8 was 832.1 °C, 839.2 °C, and 839.9 °C, when the O2 concentration in the carrying gas was 20%, 0.1%, and 0.0001%, respectively; 3) The decomposition products of MgTe2O5 were same with that of Mg2Te3O8, and its initial decomposition temperature decreased along with decreasing the O2 concentration in the gas; 4) MgTe6O13 decomposed to MgTe2O5 and TeO2 around 700 °C, and the initial decomposition temperature decreased with decreasing O2 concentration in the gas. Along with increasing temperature, MgTe2O5 converted to Mg3TeO6 through oxidation reactions, and Mg3TeO6 decomposed at elevated temperatures.
NSTL
Elsevier