High shear granulation of clay: Effect of experimental variables

This study investigates the influence of high-shear mechanical granulation parameters on the properties and distribution of a clay-based granulated powder population. The granulation parameters examined as design variables include granulation time, impeller speed, liquid addition rate, rotation mode, and binder agent incorporation. Our findings reveal significant behavioral differences across all parameters when comparing hydrophilic bentonite clays to hydrophobic synthetic hydrotalcite. For hydrophilic clays, the liquid-to-solid ratio is identified as the most critical variable, whereas it exerts minimal impact on hydrophobic hydrotalcite. This suggests the presence of a delicate balance between growth and breakage mechanisms in hydrophobic powders, involving the formation of water droplets that encapsulate particles, aligned with an increased swelling ratio. Furthermore, the addition of an acrylic binder to the bentonite mixture enhances open porosity without affecting compressive strength. These results highlight the need for tailored process modifications in the design of granulated clay-based advanced materials.