Frothers are used in flotation to aid generation of small bubbles, but little is known about the mechanisms that take place in the flotation machine to produce such an effect. Coalescence prevention is the common explanation, although the exact mechanism is obscure and almost no attention has been paid to a frother effect on bubble break-up, the other possible mechanism. This thesis presents a technique to study the effect of frothers on bubble coalescence at the generation stage (at a capillary tube) and a technique to study the effect of frothers on bubble coalescence and break-up in a turbulent field. The first technique is based on the sound bubbles emit when they form and coalesce. The sound signal was linked to bubble formation and coalescence events using high-speed cinematography. The technique has a resolution capable of detecting coalescence events that occur within 1-2 ms. The second technique allows discriminating between coalescence and break-up and is based on the exposure of a mono-size distribution of bubbles to a turbulent field generated by a three-bladed axial flow impeller. Analysis of bubble size distributions after contact with the turbulent field gives the coalescence and break-up fraction. The results show frothers reduce coalescence and alter the bubble size distribution of bubbles generated by break-up. / In the course of high-speed imaging an effect of frother on bubble shape and motion after formation was detected. Analysis of this forms the third major component of the work. A dependence of velocity on bubble aspect ratio is shown, which is in line with recent literature.

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Photocopy of typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1980. / Bibliography: leaves 125-126. / Microfiche. / x, 126 leaves, bound 28 cm

Thesis (PhD)--University of South Australia, 1996

The chemistry during regrinding is critical to flotation. It has significant effects on mineral surface properties and can lead to different mineral floatabilities. This research seeks to quantify contributing factors to changes in mineral flotation behavior with grinding and regrinding. The influence of the particle breakage mechanism on mineral floatability is also investigated. In this research, sulphide mineral surface species and hydrophobicity were analyzed by a range of techniques, including X-ray photoelectron spectroscopy (XPS), surface area measurement (BET), ethylene diamine-tetra acid (EDTA) extraction and contact angle measurements. / Thesis (PhD)--University of South Australia, 2010

Thesis (M.Eng.)(Metallurgical)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (M. Phil.)--University of Hong Kong, 2008.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.

Thesis (B.S.)--Rochester Institute of Technology, 1986. / Typescript. Includes bibliographical references (leaf 34).