The effect of the binder on the manufacture of a 5A zeolite monolith

The effect of the binder on the manufacture, by a paste extrusion process, of a 2 mm square lattice channel zeolite monolith with a 0.98 mm wall thickness and an overall diameter of 20 mm has been studied using a variety of visual and analytical techniques. Crucial factors for manufacturing defect-free 5A zeolite monoliths have been found to be the use of a binder with good plasticity properties, such as Na–bentonite, extrusion conditions, and a well-controlled drying process. Pastes containing different amounts of water and binder were characterised from the relationship between pressure drop and extrudate velocity during flow from a circular barrel into a circular die-land. From the relationship between the extrusion pressure and the extrudate velocity, six extrusion parameters were derived for each paste. A higher extrusion pressure is required when there is either a decreased water content or an increased binder content.