HYDROTHERMAL CRYSTALLIZATION OF CO-PRECIPITATED HYDROUS OXIDES FROM Al-Ti SULFATE SOLUTION.

Crystallization of Al-Ti hydrous oxides with the ratio of Al//2O//3/TiO//2 equals 1 co-precipitated from a sulfate solution containing constituent ions by ammonium hydroxide was studied between 100 degree and 700 degree C, at 10 and 100 MPa, for 0-72 h. When treated at 100 MPa for 24 h, boehmite and anatase crystallized at 100 degree -400 degree C. Boehmite changed to corundum at 500 degree C, while anatase changed to rutile at 650 degree C. Treatment of co-precipitates at 10 MPa for 24 h yielded only anatase as for titania between 100 degree C and 700 degree C, while alumina component crystallized as boehmite at 100 degree -300 degree C, alumina-ammonium-sulfate hydroxide compounds at 400 degree -500 degree C, and corundum at 600 degree -700 degree C, respectively.