Determining Key Factor of Synthetic Conditions of the Solid Sintering Preparation of Sodium Titanates by Thermo-Chemical Equilibrium Calculation

抄録

Preparing sodium titanates from sodium carbonate and anatase by the solid sintering reaction is considered as the most effective method in manufacture. However, their synthetic conditions (reactant ratio, temperature and pressure) are very complex and the preparing process relies too much on empirical evidence. Therefore, it is important to simulate the reaction accurately and find the key factors of the synthetic conditions. In this study, the thermo-chemical data of sodium titanates preparation are estimated, and then the thermo-chemical equilibrium for the solid sintering reaction between sodium carbonate and anatase is calculated through the Gibbs energy minimization method. It can be observed that the calculated results are in accordance with the experimental ones. Later, the respective effects of reactant ratio, temperature and pressure on the products are analyzed. The results show that the effect of the pressure on all the sodium titanate products can be negligible. Moreover, the contour lines for the yield and purity of a single product have been drawn, which show that both reactant ratio and temperature are key factors in the preparation of Na₂Ti₆O₁₃, and temperature is the key factor of Na₂Ti₃O₇, while in the preparation of Na₈Ti₅O₁₄, reactant ratio is the key factor.