METHOD FOR SYNTHESIS OF GAMMA-ALUMINIUM OXIDE USING PLASMA - MODIFIED ALUMINIUM AND WATER REACTION

摘要

The invention relates to a novel method for synthesis of γ-Αl₂O₃ using direct reactions between activated aluminium and pure water at 40 °C. Activation of aluminium is performed in glow discharge plasma in the presence of 3-10 Pa of hydrogen and residual gases for 10-60 min. Temperature of plasma is 60-90 °C. After activation aluminium is removed from vacuum chamber and immersed in pure water which is heated up to temperature exceeding 40 °C and maintained for more than 5 hours. Hydrogen gas and a mixture of pseudo-Boehmite - AIO(OH) and Bayerite - Al(OH)₃ are produced during the reaction between activated aluminium and water. The byproduct of Al-water reaction is annealed at 280 °C up to 5 hours under the atmospheric conditions, where byproduct is fully transformed to pseudo-Boehmite. The received pseudo-Boehmite is annealed at 500 °C up to 5 hours under the atmospheric conditions and γ-Α1₂03 is produced with the BET surface area 200 m²/g, crystallite size - 3-10 nm, level of remaining impurities: Na20 100 ppm, S0₄ 100 ppm, Fe₂0₃ 100 ppm.