The relative floatability of coal and other inherently hydrophobic solids in aqueous solutions of short-chain n-alcohols was studied. An analysis of wettability data from the literature for such systems indicated that, in general, a linear relationship existed between the solution surface tension, Y1v» and the adhesion tension, Y1v COS Ɵ (where Ɵ is the contact angle). Except for very non-polar solids, the critical surface tension of wetting, Yc (Ɵ= 0° intercept), determined with the alcohol solutions, was relatively constant and independent of the type of solid. The parameter which reflected the relative wettability of a solid was the slope of its Y1v cos Ɵ vs. Y1v line. Since wettability and floatability are not necessarily synonymous, a concept of critical surface tension of floatability, Ycf, was developed to characterize the threshold floatability condition where successful bubble-particle attachment was controlled by either adhesion or aggregate stability. In both cases it was concluded that Ycf would depend on the surface and the physical properties of a particle for a given set of flotation conditions, and that Ycf > Yc . Under certain circumstances it also appeared that selective flotation separation between particles of two inherently hydrophobic solids, A and B, would be feasible in an aqueous alcohol solution if Ycf A < Y1v ≤ Ycf B even when the two solids had the same Yc value. Small-scale flotation tests in aqueous methanol solutions were performed on narrow size fractions of several inherently hydrophobic solids. In most cases the wt.% floated decreased from a maximum to a minimum over a discrete range of Y1v, implying that the particles in a sample had a range of Ycf values. The relative floatability of a sample was given by the position of its Ycf band along the Y1v axis. For the same size fraction, floatability decreased in the order: polytetrafluoroethylene (PTFE), sulphur, medium volatile bituminous coal, molybdenite. Almost complete selective separation by flotation was achieved between samples whose Ycf bands did not overlap. Because coal is a very heterogeneous material, it was expected that a sample of fine coal particles would display a wide range of wettability and floatability characteristics, with a corresponding broad range of Ycf values. This was verified in aqueous methanol solutions for narrow particle size fractions of several high rank coal samples from the East Kootenay coalfield, British Columbia. Incremental ash content/floatability relationships were developed which could be roughly divided into two main regions'. In one, the coal particle ash content was low and independent of floatability, while in the other they were inversely related. The effects of physical and compositional factors other than ash content on the distribution of floatability within a coal sample have been discussed. For a readily floatable coal sample the yield-ash content relationships for the flotation products were independent of the flotation time and conditioning time, and were considered to approximate the ideal flotation wash-ability characteristics of the sample. Flotation washability was found to be linearly related to feed ash content. The shape and position of the incremental ash content/floatability curves for different coal samples allowed the relative wettabilities of their organic matter to be assessed in terms of degree of oxidation, rank and petro-graphic composition. Coal sample floatability in aqueous methanol solutions was found to be sensitive to small differences in surface properties which were not reflected by bulk compositional parameters. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

Thesis (MEngSc.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (M.S.)--Ohio University, August, 1982. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, June, 1983. / Title from PDF t.p.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 121-125). Also available via the Internet.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

The effect of manipulated variables on the flotation response of run-of-mine coal supplied by Bullmoose Coal Mine (North East British Columbia) was studied in a pilot flotation column and a batch mechanical cell using experimental designs of the factorial class after the coal had been stage crushed and ground to about 96 percent minus 600 µm, the feed size to the flotation circuit at Bullmoose Coal Mine. The objective was to optimise statistically the two flotation units usings (1) screening designs, (2) the steepest ascent technique, and (3) central composite designs, and to compare cell performance. The efficiency index was employed as the primary optimisation criterion. The two cells yielded comparable efficiency indices, but the product ash content of clean coal from the flotation column was consistently lower. Evaluation of the efficiency indices of individual size fractions was also carried out at the optimum conditions of each cell. The approach taken was to separate the feed into individual size fractions, retain the fractions separately, and float them separately. The flotation column yielded higher efficiency indices and lower product ash content when a feed with 15 percent solids was floated. Results obtained by floating individual size fractions at 2 percent solids indicated that it is difficult to float sizes above 300 µm in both cells at such a low pulp density. Below 300 µm, the performance of both cells was comparable. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1913. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed April 16, 2009)

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains x, 164 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 119-121).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 158-163). Also available via the Internet.