UBC Theses and Dissertations
Wettability and floatability of coal macerals as derived from flotations in methanol solutions Holuszko, Maria Ewelina
In this study wettability and floatability of coal petrographic components were examined using the concept of critical surface tension. Two techniques were studied; film flotation and small-scale flotation tests. Both tests use Zisman’s concept of critical surface tension of solids. In these tests particles are separated according to their respective critical surface tension of wettability (film flotation) or critical surface tension of floatability (small-scale flotation). Surface heterogeneity of coal particles arises from the chemical composition of coal surface. The coal macerals are known to have different chemical composition and surface properties. Surface properties of macerals and their flotation response have usually been evaluated with the contact angle or direct flotation tests. In this study, the estimation of surface properties of coal macerals was accomplished by studying their critical surface tension of wettability and floatability. The wettability distributions of coal samples of various petrographic composition were obtained from film flotation. Wettability of petrographic components was evaluated in terms of an average critical surface tension of wettability. In small-scale flotation experiments, coal particles were separated according to their critical surface tension of floatability. Differences in floatability and wettability distributions of coal lithotypes and maceral concentrates are discussed. Microscopic examination of the products from film and small-scale flotations was used to further study the effect of coal petrographic composition on the wettability and floatability.
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