An improved ultrasonic disaggregation method for analysis of minerals in shales

摘要

Traditional disaggregation methods for mineral separation of sedimentary rocks are not appropriate for shales with complex mineralogy and grain sizes. In this study, we improved the ultrasonic disaggregation and stepwise separation method for minerals in shales, and applied it to analyse shale samples from the Silurian Longmaxi Formation of the Sichuan Basin, China. The Longmaxi Formation shales are mainly composed of clay minerals, quartz, calcite, dolomite, albite, and K-feldspar, and are cemented by SiO2. This method processes shale samples as ultrasonic disaggregation followed by stepwise separation of minerals using gravitational deposition and centrifugation. Field emission scanning electron microscope (FE-SEM) images were obtained for different components of this ultrasonic disaggregation and stepwise separation method. Information obtained by this method can also be used to quantify the hydrodynamic forces acting on the Longmaxi Formation sediments during the syngenetic stage. [Received: October 25, 2018; Accepted: November 21, 2018]