Dispersion of kaolin particles with carboxymethylated xylan.

In this work, the performance of carboxymethylated xylan (CMX) as a dispersant for kaolin particles in an aqueous system (20 g/L) was systematically investigated. The influence of process parameters, such as pH and CMX dosage, on the kaolin dispersions was also determined. Adsorption studies revealed that CMX had a maximum adsorption of 2.48 mg/g on kaolin particles under the treatment conditions of pH 6, 15 mg/g CMX/kaolin, 30 °C and 30 min. The minimum zeta potential of − 33 mV and the highest stability for the kaolin dispersions were found under the same treatment conditions using photometric dispersion, vertical scan analysis and turbidimetry. Isotherm and kinetic studies revealed that the adsorption of CMX on kaolin particles tended to significantly impact the zeta potential and relative turbidity of the kaolin dispersion, but the zeta potential did not necessarily predict the high stability of the kaolin dispersion. CMX improved the stability of the kaolin dispersions more than unmodified xylan (UX) and mechanical stirring. [ABSTRACT FROM AUTHOR]