Simultaneous purification and modification process for organobentonite production

Abstract

Bentonites are commonly subjected to a water and energy intensive purification process in order to obtain high-grade montmorillonite, prior to modification to suit technological needs. In this study, the purification and modification processes were combined in order to minimize costs. A method for the production of organobentonite from roughly purified Na-bentonite from Resadiye, Turkey, was proposed with a quaternary alkylammonium salt hexadecyl trimethyl ammonium bromide. Further purification and ion exchange reactions were simultaneous within a centrifugal separation process, followed by the removal of excess modifier agent using the flotation method. The parameters of centrifugal force, feed solid content for Falcon concentrator and modification time, and the amount of alcohol for ion exchange reactions were optimized. Ammonium intercalated organoclays were characterized by X-ray diffraction analysis, thermogravimetric analysis, and swelling tests in organic liquids. An optimum flow sheet for the simultaneous purification and modification process yielding a 97% pure organobentonite with a 2.02 nm basal spacing was developed. (C) 2014 Elsevier B.V. All rights reserved.