Abstract: Pseudoboehmite with large pore volume and high specific surface area was successfully prepared by hydrothermal precipitation of sodium aluminate solution using SB pseudoboehmite (from Condea, Germany) as the seed, combined with dispersing and washing the precipitate with ethanol. Effects of the composition of the sodium aluminate solution (concentration of Al2O3 and molar ratio of Na2O/Al2O3) and the precipitation time on the precipitation yield of Al2O3 and Na2O and physico-chemical properties of the precipitates such as pore volume, specific surface area, and Na content were studied. When the sodium aluminate solution with Al2O3 concentration of 100-140 g/L and Na2O/Al2O3 molar ratio of 1.30-1.45 was used, about 30% precipitation yield of Al2O3 was obtained at 125 ℃ with a low seed ratio of 1.0. The obtained pseudoboehmite has a large pore volume of 0.84 cm3/g, a high specific surface area of 213.6 m2/g, and a low Na2O content less than 0.3% after the third precipitation cycle, and some of its properties are even superior to that of the SB powder. This study provides an preparation route for high value pseudoboehmite from the low-cost sodium aluminate solution.

Key words: sodium aluminate solution, SB powder, hydrothermal seed precipitation, pseudoboehmite, large pore volume, high specific surface area