Effect of water vapor pressure on the phase composition of lithium monoaluminates formed in the interaction of aluminum hydroxide and lithium carbonate

Resumo

It is shown that the partial water vapor pressure affects the phase composition of lithium monoaluminates formed when aluminum hydroxide (gibbsite) and lithium carbonate are heated in air, in the atmosphere of helium, and in a dynamic vacuum. When the mixture is heated to 800°C in an air atmosphere with partial water pressure of 1300 Pa, a nearly single-phase lithium monoaluminate α-LiAlO₂ is formed. In the reaction in the atmosphere of helium, in which the partial water vapor pressure does not exceed 4 Pa, γ-LiAlO₂ is formed together with α-LiAlO₂, with the content of the former exceeding that produced in the reaction in air. When the mixture is heated under dynamic vacuum conditions with partial water vapor pressure lower than 0.1 Pa, mostly γ-LiAlO₂ is formed.