Effect of Mechanical Activation on Reaction between Boehmite and Lithium Carbonate

Abstract

We have studied the effect of mechanical activation of a boehmite + lithium carbonate mixture in an AGO-2 planetary activator on phase transformations during heat treatment in air. The results demonstrate that heat treatment of the starting boehmite + lithium carbonate mixture leads to the formation of γ-Al2O3 as a reaction intermediate, which reacts with lithium carbonate to form α-LiAlO2. Heat treatment of the activated mixture leads to the formation of gamma-aluminum oxide and an unidentified intermediate phase, presumably, metastable lithium aluminate, which transforms into α-LiAlO2 at temperatures above 500°C. We have proposed a possible mechanism of the formation of this phase, which involves exchange of protons of boehmite with lithium cations, followed by the release of water and carbon dioxide.