Steam Hydrolysis of Lithium Hydride

Abstract

Steam hydrolysis of lithium hydride was studied at various temperatures (20°C–80°C). To monitor the reaction rate, hydrogen flow was recorded as a function of time. Phase composition of the reaction products was analyzed by XRD spectroscopy. A variation in the reaction mechanism was found for temperatures lower than 70°C when lithium hydride was reduced to 10% of the initial amount. Using XRD analysis it was found that the main product obtained at temperatures ranging from 20°C to 70°C was LiOH.H2O. By increasing the temperature, the percentage of dehydrate slowly increases, and at 80°C the dehydrate represents the main product. A simple model for steam hydrolysis of lithium hydride is proposed taking into consideration the experimental results. The behavior of hydrogen flow was related to water vapor pressure and unreacted lithium hydride amount. The change in the reaction mechanism was related to a variation of water uptake (from the solid phase to the gas phase) to the lithium hydride surface.