The Rheological Behavior of Kaolin Suspensions
Apinon Nuntiya* and Sitthisak Prasanphan* Author for corresponding; e-mail address: anuntiya@chiangmai.ac.th
Volume: Vol.33 No.3 (SEPTEMBER 2006)
Research Article
DOI:
Received: 16 Febuary 2006, Revised: -, Accepted: 27 June 2006, Published: -
Citation: Nuntiya A. and Prasanphan S., The Rheological Behavior of Kaolin Suspensions, Chiang Mai Journal of Science, 2006; 33(3): 271-281.
Abstract
The rheological behavior of three kaolins (Narathiwat, Lampang and Ranong) having different chemical and mineral compositions were studied. The viscosity and thixotropy of kaolin suspensions were measured as a function of solid content, pH and electrolyte concentrations. From rheological measurements, it was found that the viscosity and thixotropy increased with the increasing of the solid content. The highest viscosity of Narathiwat, Lampang and Ranong kaolins showed at pH 2, 6 and 4, respectively. However, thixotropy of three kaolins tends to increase with decreased pH. Plots of Binghan yield stress against pH at different ionic strengths intersect at about pH 7.1, 6.8 and 4.0, for Narathiwat, Lampang and Ranong kaolins, respectively. These values are identified with the isoelectric point of the particle edge surface. The rheological behavior of kaolins may be explained in terms of the influence of solid content, particle size, morphology, and pH and electrolyte concentrations on particle interaction.