Abstract: Hydration behaviors of the ρ-Al2O3 were investigated by the determinations of temperature and viscosity of the slurries and the phase composition analysis and microstructure observation of the hydrated products in 9 media.It has been shown that, hydration process of the ρ-Al2O3 will be prevent in acidic medium and promote in alkaline medium.Hydration products of the ρ-Al2O3 are mainly crystalline granular bayerite in water and alkaline media and amorphous boehmite in acidic medium.

Key words: ρ-Al2O3;hydration behavior;phase composition;microstructure