Effect of ultrasound on the dispersion of kaolinite and sepiolite suspensions with and without sodium silicate

Document Type : Research Article


Department of Mining Engineering, Faculty of Engineering and Natural Sciences, Konya Technical University (KTUN), Konya, Turkey


In this study, the effect of the ultrasound process on the dispersion of kaolinite and sepiolite suspensions in the absence and presence of sodium silicate was investigated. The effects of ultrasonic device-dependent parameters such as power, treatment time, and application method (batch and continuous) on the dispersion of kaolinite and sepiolite suspensions were determined. Results of the studies carried out without sodium silicate showed the suspension stability values of kaolinite and sepiolite minerals presented some differences. While the stability of the kaolinite suspension decreased at high power ultrasonic values, it increased slightly for the mineral sepiolite. Also, the stability of the kaolinite suspension decreased, while the stability of sepiolite increased with a prolonged ultrasonic treatment time. It was also found that the application of ultrasound did not affect the isoelectric point (iep) of these clay minerals. In the presence of sodium silicate as a dispersant, the dispersion of these mineral suspensions increased depending on ultrasonic power and treatment time. Moreover, higher suspension stability values were obtained with the ultrasound application. In addition, the negative zeta potential values of clays after ultrasonic treatment were higher than those without ultrasound. The findings obtained showed that kaolinite and sepiolite suspensions were more successfully dispersed by ultrasonic treatment.

Graphical Abstract

Effect of ultrasound on the dispersion of kaolinite and sepiolite suspensions with and without sodium silicate


  • The effect of ultrasound process on the dispersion of kaolinite and sepiolite suspensions was studied.
  • The ultrasonic had no effect on the isoelectric point of clay minerals.
  • The ultrasonic treatment improved the dispersion of kaolinite and sepiolite with sodium silicate.
  • The ultrasonic treatment led to more negative zeta potentials for kaolinite and sepiolite.


[1] J.S. Laskowski, R.J. Pugh, Dispersions stability and dispersing agents, in : J.S. Laskowski, J. Ralston (Ed.), Developments in Mineral Processing, New York, Elsevier, 1992, pp. 115-171.
[2] N. Yildiz, M. Erol, B. Baran, Y. Sarikaya, A. Çalimli, Modification of rheology and permeability of Turkish ceramic clays using sodium silicate, Appl. Clay Sci. 13 (1998) 65-77.
[3] F. Andreola, M. Romagnoli, E. Castellini, Role of the surface treatment in the deflocculation of kaolinite, J. Am. Ceram. Soc. 89 (2006) 1107-1109.
[4] Sari, M. Tuzen, D. Citak, M. Soylak, Equilibrium, kinetic and thermodynamic studies of adsorption of Pb(II) from aqueous solutions onto Turkish kaolinite clay, J. Hazard. Mater. 149 (2007) 283-291.
[5] M. Jiang, X. Jin, X. Lu, Z. Chen, Adsorption of Pb(II), Cd(II), Ni(II) and Cu(II) onto natural kaolinite clay, Desalination, 252 (2010) 33-39.
[6] D.R. Dinger, Rheology for ceramics, Dinger Ceramic Consulting Service, Clemson, 2002, pp. 1-27.
[7] J.E. Kogel, N.C. Trivedi, J.M. Barker, S.T. Krukowski, Industrial Minerals and Rocks: Commodities, Markets and Uses, in: J.E. Kogel, N.C. Trivedi, J.M. Barker, S.T. Krukowski (Ed.), Society for Mining, Metallurgy and Exploration Inc., Colorado, USA, 2006, pp. 1548.
[8] G. Onal, M. Ozer, F. Arslan, Sedimentation of clay in ultrasonic medium, Miner. Eng. 16 (2003) 129-134.
[9] N.E. Altun, J.Y. Hwang, C. Hicyilmaz, Enhancement of flotation performance of oil shale cleaning by ultrasonic treatment, Int. J. Miner. Process. 91 (2009) 1-13.
[10] T.J. Mason, Chemistry with Ultrasound, Society of Chemical Industry, New York, 1990, pp. 195.
[11] J. Gallego-Juarez, New technologies in high-power ultrasonic industrial applications, Proceedings of IEEE Ultrasonics Symposium, Cannes, France, 1994.
[12] M. Smythe, R. Wakeman, The use of acoustic fields as a filtration and dewatering aid, Ultrasonics, 38 (2000) 657-661.
[13] S.G. Ozkan, Beneficiation of magnesite slimes with ultrasonic treatment, Miner. Eng. 15 (2002) 99-101.
[14] G. Gurpinar, Investigation of the usability of ultrasound waves in mineral processing (in Turkish), PhD Thesis, Osmangazi University, Department of Mining Engineering, 2007.
[15] S.G. Ozkan, H.Z., Kuyumcu, Investigation of mechanism of ultrasound on coal flotation, Int. J. Miner. Process. 81 (2007) 201-203.
[16] M. Xu, Y. Xing, X. Gui, Y. Cao, D. Wang, L. Wang, Effect of ultrasonic pretreatment on oxidized coal flotation, Energ. Fuel. 31 (2017) 14367-14373.
[17] M. Ozer, M.O. Kangal, Y.E. Benkli, F. Arslan, G. Onal, Effect of ultrasonic treatment on the sedimentation of clays, Proceedings of the 9th  Balkan Mineral Processing Symposium, ed. G., Onal et al., 63-68,  Istanbul,Turkey, 2001.
[18] K. Esmeli, Investigation of effect of ultrasound on stability of mineral suspensions in the presence of different reagents (in Turkish), PhD Thesis, Konya technical university, Department of Mining Engineering, 2019.
[19] C. Schilde, C. Mages-Sauter, A. Kwade, H.P. Schuchmann, Efficiency of different dispersing devices for dispersing nanosized silica and alumina, Powder Technol. 207 (2011) 353-361.
[20] S.A. Adio, M. Sharifpur, J.- P. Meyer, Influence of ultrasonication energy on the dispersion consistency of Al2O3-glycerol nanofluid based on viscosity data, and model development for the required ultrasonication energy density, J. Exp. Nanosci. 11 (2016) 630-649.
[21] Draganovic´, A. Karamanoukian, P. Ulriksen, S. Larsson, Dispersion of microfine cement grout with ultrasound and conventional laboratory dissolvers, Constr. Build. Mater. 251 (2020) 119068.
[22] J.L. Pe´rez-Rodrı´guez, F. Carrera, J. Poyato, L.A. Perez-Maqueda, Sonication as a tool for preparing nanometric vermiculite particles, Nanotechnology, 13 (2002) 382-387.
[23] J.L. Pe´rez-Rodrı´guez, A. Wiewio´ra, J. Drapala, L.A. Pe´rez-Maqueda, The effect of sonication on dioctahedral and trioctahedral micas, Ultrason. Sonochem. 13 (2006) 61-67.
[24] M. Alkan, O. Demirbas, M. Dogan, Electrokinetic properties of kaolinite in mono-and multivalent electrolyte solutions, Micropor. Mesopor. Mat. 83 (2005) 51-59.
[25] E. Sabah, U. Mart, M. Çinar, M. S. Çelik, Zeta potentials of sepiolite suspensions in concentrated monovalent electrolytes, Sep. Sci. Technol.42 (2007) 1-14.
[26] T. Chen, Y. Yang, Y. Zhao, F. Rao, S. Song, Evaluation of exfoliation degree of montmorillonite in aqueous dispersions through turbidity measurement, RSC Adv.8 (2018) 40823-40828.  
[27] P. Somasundaran, Principles of flocculation, dispersion, and selective flocculation, in: P. Somasundaran (Ed.), AIME, New York, 1980, pp. 947-976
[28] J.L. Amorós, V. Beltrán, V. Sanz, J.C. Jarque, Electrokinetic and rheological properties of highly concentrated kaolin dispersions: Influence of particle volume fraction and dispersant concentration, Appl. Clay Sci. 49 (2010) 33-43.
[29] B. Ersoy, A. Evcin, T. Uygunoglu, Z.B. Akdemir,  W. Brostow, J. Wahrmund, Zeta potential-viscosity relationship in kaolinite slurry in the presence of dispersants, Arab. J. Sci. Eng. 39 (2014) 5451-5457.
[30] P. Parsonage, D. Melven, A.F. Healey, D. Watson, Depressant function in flotation of calcite, apatite and dolomite, in: M.J. Jones and R. Oblatts (Ed.), Reagents in the minerals industry,  Institute  of Mining and Metallurgy, London, 1984, pp. 33-40.
[31] F. Andreola, E. Castellini, G. Lusvardi, L. Menabue, M. Romagnoli, Release of ions from kaolinite dispersed in deflocculant solutions, Appl. Clay Sci. 36 (2007) 271–278.
[32] M. Ma, The dispersive effect of sodium silicate on kaolinite particles in process water: implications for iron-ore processing, Clay. Clay Miner. 59 (2011) 233-239.
[33] W. Mekhamer, The colloidal stability of raw bentonite deformed mechanically by ultrasound, J. Saudi Chem. Soc. 14 (2010) 301-306.