Microcharacterization of coal components for beneficiation

Automated image analysis (AIA) of mineral association with the coal matrix was shown to be helpful in predicting froth flotation behavior of an Indiana No. 3 and Upper Freeport coal when the association was expressed in terms of the relative amount of particle surface covered by coal and mineral phases. AIA measurements of the amount and quality of material with more than 80% of the particle surface covered by coal were found to relate to the pyrite and ash reduction observed in froth collected after 1.5 minutes of flotation. Results accurately predicted more ash reduction by froth flotation for the Indian No. 3 coal than for the Upper Freeport coal. The association distribution derived from AIA also showed the changes in ash reduction as a function of cleaning severity. In another task, analysis of the repeatability of coal-mineral matter association results for a single pellet of coal indicated that characterization of 3000 particles should be adequate to provide {plus minus}16% relative repeatability for phases measured to be present at the 5% level. 3 refs., 3 figs., 4 tabs.