Abstract:An alternative solution for the direct formation of g-LiAlO₂ was presented by a modified combustion method, to apply it to rather simple systems, utilizing non-oxidizer compounds such as Al₂O₃ and LiOH, and urea as fuel. LiAlO₂ was prepared via non-stoichiometric 1:1, 1.5:1 and 2:1 of Li/Al molar ratios at 900 and 1000 °C for 5 min. Textural and structural characterization of γ-LiAlO₂ was performed. Also, the effect of different Li/Al molar ratios on material morphology and its stability before high gamma radiation gradients was evaluated. The results showed that the crystal structures of the obtained powders were γ-LiAlO₂ and a-LiAlO₂, depending on the Li/Al molar ratio. The results obtained demonstrate that g-LiAlO₂ microbricks, polyhedral and laminar shapes can be successfully synthesized with the proposed method and without any subsequent process. Additionally, gamma irradiation showed that the g-LiAlO₂ obtained does not decompose, forming only small amounts of Li₂CO₃. It can be established that the irradiation produces consolidation, which is not favourable for an efficient extraction of tritium. Finally, it could be demonstrated that nitrate precursors are not necessary in the combustion method to produce γ-LiAlO₂ with high purity.

Key words: urea; oxide; combustion; lithium aluminate; ceramic