Effect of Ultrasound on the Dispersion of Kaolinite and Sepiolite Suspensions With and Without Sodium Silicate

Abstract

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.