Characterization and rheological properties of kaolinite-silicon oil pastes

Abstract

A description of experiments carried out to determine the effect of some parameters on the extrusion behavior of particulate pastes is given. The effects of particle size. solid/liquid ratio, temperature, shear rate, and die dimensiones on rheological behavior of kaolinite-silicon oil pastes were investigated. These pastes were prepared by mixing kaolinite powder with chosen amounts of silicon oil. Capillary rheometry was used to determine the extrusion properties of the pastes. All pastes were found to exhibit non-Newtonian, pseudoplastic behavior under all experimental conditions. The viscosity decreased with an increase in temperature and particle size and with a decrease in solid/liquid ratio. The whole paste was properly described by the Herschel-Bulkley model and exhibited a shear thinning behavior. The yield stress increased with an increase in particle size and kaolinite amount and a decrease in temperature, reflecting the increase in paste viscosity. The flow behavior index, n, varied in the range of 0.077-0.534. The Arrhenius model gave a good description of the temperature effect on the shear viscosity of paste, and the E-a value appeared in the range of 7.4-32.6 kJ/mol.