Water Wettabilities of Foreign Coals

Abstract

The previous report proved that, based on an equation obtained by modifying the Washburn equation, water wettability of powder coal itself can be measured by the penetration rate method.In the present experiment, 18 kinds of foreign coals different from one another in analytical values were prepared to measure their water wettabilities by the penetration rate method. The experimental results are summarized as follows : 1) The penetration rate method was widely applicable to evaluate the surface properties of foreign coals.2) Foreign coals subjected to the experiments, greatly differents in analytical values, exhibited conspicuous differences in surface characteristics; some of them were very wettable and the others were not wetted at all.3) Water wettability of coals was directly proportional to inherent moisture of coal.At the same time, there were indications, although not clear say, that water wettability was proportional to volatile matter but inversely proportional to ash content or fixed carbon.These results suggests that relatively immature coals of both large water content and high volatile matter value are wettable with water.