Extrusion of zeolites: Properties of catalysts with a novel aluminium phosphate sintermatrix Original Research Article

A novel type of mechanically strong zeolite extrudates is introduced, in which the zeolite crystals, here ZSM-5, are embedded in a sintermatrix of aluminium phosphate with the crystal structure of tridymite. The pore size distribution in the matrix can be tailored through both, the choice of the size of the embedded particles and their amount in the extrudates. At zeolite concentrations of 50% (w/w) or higher, the mean pore diameter of the matrix (Dpore) depends on the zeolite crystal size only, and amounts to Dpore ≈ 0.25Dparticle. Other than conventional matrices on alumina basis, the AlPO4 matrix does neither provide catalytic self-activity, nor does cause any alumination of the zeolite framework.