Improvement in phase purity and yield of hydrothermally synthesized smectite using Taguchi method

Smectite is widely used in many industrial fields and material applications. Although the high phase purity and yield of synthetic smectite are paramount for advanced applications, few studies have investigated these aspects. In this work, the phase purity and yield of synthetic smectite were estimated for the first time using a quantitative phase analysis through X-ray diffraction and Rietveld method software. The Taguchi method was used to optimize the phase purity and yield of synthetic smectite, and the effects of synthesis factors are discussed. Based on the trioctahedral smectite formula Na2x(Al2(1-x)Mg2x□)Si4O10(OH)2, an Na2O-MgO-Al2O3-SiO2-H2O system was used for smectite synthesis at temperatures of 200 °C and 220 °C, for durations of 48-96 h and pH values of 7, 9, and 11. The results indicate that the duration, starting material, and type of mineralizer are the three most important factors affecting the phase purity and yield of synthetic smectite. For the synthesis conditions optimized by the Taguchi method in this study, the phase purity and yield of the synthetic smectite can reach up to 92.5% and 88.3%, respectively. These results can contribute to an improved understanding of the factors that control the phase purity and yield of synthetic smectite and provide an efficient method for the synthesis of high-quality smectite for advanced applications.