Sodium lignosulfonate and sodium polyacrylate mixture as a dispersing agent for calcium carbonate suspensions

Abstract

Preparation of low viscous and high filler loaded calcium carbonate suspension in the aqueous medium is an industrial requirement. To minimize disturbance of handling and processing, to reduce transportation costs and to avoid transportation of excess water, calcium carbonate slurries need to be produced in high solid content. The currently available dispersing agent is less efficient. Therefore an investigation was carried out to prepare an efficient dispersing agent. A different percentage of sodium lignosulfonate was used to mix with the sodium salt of poly (acrylate) to prepare combined dispersing agents. Dispersing agent samples were tested in calcium carbonate powder – water mixture at 45% solid content. Viscosity values vs adding dispersing dosage were measured with a Brookfield viscometer in order to select the more efficient dispersing combination. The maximum filler loading percentage was conducted base on the selected dispersing combination. Different shear rates were applied to higher filler loaded calcium carbonate suspension to the optimized most dispersed shear rate at the lowest viscosity. Final calcium carbonate suspension and temporary prepared suspension particle size, polydispersity index and zeta potential values were measured and compared. The findings were then applied to prepare pilot-scale calcium carbonate suspension. The developed combined dispersing agent was more efficient. It was possible to prepare calcium carbonate suspension with high solid loading (75%) at low viscosities.