Characterization of size/composition and shape of fine coal and mineral particles

As particle size decreases, it becomes increasingly more difficult to measure their size, composition and shape characteristics. Two techniques for determining the size/composition characteristics of fine coal were evaluated using a ;The second technique applied to the coal used a scanning electron microscope coupled with an energy dispersive spectrophotometer (SEM/EDS) to measure the size/composition characteristics of coal on a particle-by-particle basis. Applications of this technique to ;A scheme for describing particle shape was developed in which shapes are classified according to their angular and elongational features and corresponding quantitative shape descriptors were defined. The shape features of particle profiles were measured using a polygon-fitting technique which was incorporated into the SEM/EDS system. Compared with other techniques such as Fourier and fractal analyses, the new shape description scheme seems to provide a better description of the angular and elongational features. The shape analysis technique was applied to quartz particles which had been ground under different conditions so as to produce sets of angular and more rounded particles. The technique was able to distinguish between rounded and angular particles and to quantify their specific shape features. The results were clearly consistent with visual observations of the particles.