Reinvestigations of the Li2O–Al2O3 system. Part I: LiAlO2 and Li3AlO3

Reinvestigations of the Li2O–Al2O3 system focused on the synthesis and properties of LiAlO2 and Li3AlO3 phases have been performed with the help of XRD and IR measuring techniques and Li2CO3, LiOH.H2O, Al2O3-sl., α-Al2O3, Al(NO3)3.9H2O and boehmite as reactants. Results of investigations have shown the formation of α-, β-, and γ- polymorphs of LiAlO2. It was found that only the use of LiOH.H2O as a reactant yields to β-LiAlO2 as a reaction product. On the other hand, it was proved that Li3AlO3 does not form in the Li2O–Al2O3 system. A new method for the synthesis of α-LiAlO2 was developed, consisting in grinding the mixture of Li2CO3 and Al(NO3)3.9H2O and heating the obtained paste at the temperature range of 400–600°C. The IR spectroscopy was used to characterize obtained phases.