Fine coal washability-liberation analysis by cone-beam X-Ray microtomography

A new method based on cone-beam x-ray microtomography is described for direct determination of the three-dimensional liberation spectrum of multiphase particles 100 microns in size or less. Such a technique may provide the basis for more detailed and accurate washability analysis in fine coal characterization. Previous research has demonstrated the ability to use traditional medical x-ray CT scanners to determine the liberation spectrum of coarse coal particles of 1 cm in size (washability analysis). Now it is possible to determine fine coal (-100 mesh) washability by cone-beam microtomography. Rather than stacking a series of two-dimensional slices for volumetric imaging as is commonly done in traditional medical computed tomography, with this new microtomographic technique a three dimensional reconstruction image array is prepared directly from the two-dimensional projections for cone beam geometry. The advantage of high spatial resolution (approximately 15 um) with a microfocus x-ray generator combined with the benefit of direct processing of three-dimensional data, provide an excellent opportunity to overcome many of the limitations of current techniques being used for fine coal washability analysis.