1976 Volume 25 Issue 274 Pages 658-662
The binary gel pellets were prepared in order to make clear the pore structure of silica-magnesia gel and the mechanism of the formation of solid acids or bases through a mixing process.
Silica and magnesia hydrogels were mixed in their suspension, drained, molded in a cylindrical vessel of 5mmφ and 5mm height, dried at room temperature and calcined at 500°C for 2 to 3hrs.
The pore volume distributions, surface areas and the amount of acids or bases were measured by the mercury penetration method, nitrogen adsorption method and titration method, respectively.
The followings were recognized:
(1) Macropore volume increased with increasing MgO content.
(2) Specific surface area decreased linearly with increasing MgO content.
(3) Formation of acid point or disappearance of base point seems to take place at the contact place of both gel particles.
(4) In the mixing process, both SiO2 and MgO particles behaved as agglomerates, the former being the agglomerate with transitional structure between cubic and orthorhombic packings, the latter the one of petal-like thin film.