3D Fine Coal Characterization and Washability Analysis by X-Ray Microtomography

摘要

Previous research has demonstrated that coarse coal washability data provided by conventional medical x-ray computed tomography (CT) analysis compares very favorably with data obtained from traditional laboratory float-sink tests. As the resolution and the techniques for 3-D geometric analysis have advanced in the last decade, it is now possible to map in detail coal particles as fine as 50 microns in three-dimensional digital space with a spatial resolution of 5 microns. The application of the principles of CT at the microscale level, or microtomography, allows quantitative investigation of objects in three dimensions. For cone beam x-ray microtomography, a whole 3-D data set is acquired with only one rotation of the sample. This provides for fast data acquisition, better x-ray utilization, and uniform spatial resolution in all directions. Only recently, practical 3D x-ray microtomography systems have been developed. Now a state-of-theart, flexible cone beam x-ray microtomography system, the Konoscope, has been designed and installed at the University of Utah for the quantitative analysis of multiphase materials in three dimensions. The Konoscope microtomography system obtains micron-scale resolution over centimeter diameter samples. This system is capable of imaging through high-density material and the resulting 3D digital images are quite suitable for the characterization of coal particles which have a wide density range of components from organic macerals, to mineral matter including pyrite. The utilization of x-ray microtomography not only allows for quantitative analysis of multiphase systems but also allows for textural characterization and the determination of phase continuity. In this paper, we present information regarding the current use of this new facility and preliminary results from washability analysis of fine coal using cone beam x-ray microtomographic techniques.