Molded articles based on pyrogenically produced titanium dioxide method for their manufacturing and uses

摘要

The invention concerns pressed pellets based on pyrogenically produced titanium dioxide having the following properties: -outside diameter 2 to 15 mm -area according to BET surface 35 to 65 m2/g -DIN 66 131 -Total pore volume 0.3 to 0.8 m3/g -crushing strength 40 to 300 N -pore size distribution no pores <10 nm in - diameter, at least 80% - of the pores in the - range of 10 to 70 nm - diameter -composition at least 94% by weight - of TiO2 (predominantly, - i.e. >50% by weight of - anatase) remainder SiO2 - and Al2O3. - They are made by mixing pyrogenically produced titanium with a foaming agent such as urea and with water, where called binder such as kaolin and also with a binder such as kaolin and also with a pelletizing accessory such as wax and by compacting the material which then is dried at a temperature of 80 DEG to 120 DEG C. and is comminuted into a powder which then is pressed by known means and the pressed articles are annealed for 0.5 to 4.5 h at a temperature of 400 DEG to 600 DEG C. The pressed articles are used as catalyst-carriers or as catalysts.