Peptization Control of Composite Materials Containing Water Glass for Spray Drying of Catalysts

Abstract

Silica‐based composite particles are complex catalyst materials that are widely used in petrochemistry. The preparation of particles that are well defined in form, composition, and chemical and rheological behavior by spray drying of suspensions remains an important industrial challenge. Here, zeolite HY, kaolin, and the cheap binder water glass are used. Experimental and model regimes of slurry peptization are analyzed based on their pH value, zeta potential, and mixing speed to control the process. The results show a pseudoplastic behavior of the silica slurries for zeta potential below 20 mV, which is explained by surface charge, hydroxyls, and pH‐dependent coagulation. Thus, a quick acidification of the slurry, additional mechanic shear, and subsequent pH control during spray drying enable control of peptization kinetics.

Binder Selection to Modify Hydrocarbon Cracking Properties of Zeolite-Containing Composites

“…In this case, the binding comes from the precipitation of the binder from the liquid phase. 12,18 However, this was not observed in the sample PS, where silica nanoparticles from LUDOX are present in the formulation. These nanoparticles can agglomerate faster to other bigger particles and can cover all their surface.…”