The zeta potential of kaolin suspensions measured by electrophoresis and electroacoustics
- 317 Downloads
The zeta potentials of kaolin dilute and concentrated suspensions were monitored using the techniques of electrophoresis and electroacoustics, respectively. The effect of addition of salt (KCl), a polymer material (Triton X-100), and an anionic surfactant (sodium dodecyl sulphate, SDS) on the suspension properties was investigated by electrophoresis. Electroacoustics was employed for the measurement of zeta potentials for the highest possible kaolin content in suspension and the effect of dilution. The effect of aging of a freshly prepared sample and kaolin isoelectric point was also studied. Using both techniques it was noted that there was no isoelectric point, just a maximum value in the magnitude of the kaolin suspension zeta potential. These maxima were observed also in the presence of Triton X-100 and SDS. An increase of the concentration of KCl and SDS in suspension shifted the maxima towards more acidic values, while in the presence of Triton X-100 the position of the zeta potential maxima remained constant. Electroacoustic techniques revealed that a freshly prepared concentrated suspension requires about six hours to equilibrate to achieve a steady zeta potential. Diluting the concentrated suspensions led to decrease of the zeta potential as ions bound to the surface desorbed and screened the surface charge. The zeta potential maxima remained unchanged even after heating the powder in an oven at 200°C (to remove any organic material) thereby suggesting that the most likely explanation for the maxima is isomorphic substitution.
Keywordskaolinite kaolin concentrated aqueous suspensions electrophoresis electroacoustics zeta potential isomorphic substitution
Unable to display preview. Download preview PDF.
- 2.Lapčík, L., Alince, B., and van de Ven, T. G. M., J. Pulp Pap. Sci. 21, J19 (1995).Google Scholar
- 3.Rice, B. P., Chen, C. G., Cloos, L., and Curliss, D., SAMPE J. 37, 7 (2001).Google Scholar
- 4.Chen, C. G. and Curliss, D., SAMPE J. 37, 11 (2001).Google Scholar
- 5.Jama, C. and Delobel, R., in Proceedings of ICCE-12, Tenerife, Spain, 2005.Google Scholar
- 6.Martínez-Vilariño, S., Hui, D., Miller, S. G., and Daniel, L., in Proceedings of ICCE-12, Tenerife, Spain, 2005.Google Scholar
- 7.Ophir, A., Dotan, A., Dodiuk, H., Belinsly, I., and Kenig, S., in Proceedings of ICCE-12, Tenerife, Spain, 2005.Google Scholar
- 13.www.colloidal-dynamics.com. Application note.Google Scholar
- 30.Olhoeft, G. R., Tables of Room Temperature Electrical Properties for Selected Rocks and Minerals with Dielectric Permittivity Statistics, p. 24. US Geological Survey Open File Report 77-993, 1979.Google Scholar
- 35.Waters, K. E., Greenwood, R. W., Rowson, N. A., Lapčík, L., Jr., and Lapčíková, B., Paper No. 159E, World Congress on Particle Technology 5. Orlando, Florida, 2006.Google Scholar