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Title: Froth flotation of china clay
Author: Hanumanth, G. S.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1987
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An experimental and theoretical study of froth flotation separation of kaolinite from other associated minerals of china clay is presented herein. A new laboratory flotation equipment has been designed and built for the above study. Its novel features are discussed. Effects of physico-chemical variables such as pH, initial solid concentration of feed, froth height and air flowrate are studied by systematically carrying out series of semi-batch kinetic experiments. pH is shown to influence both recovery and grade of the product. The effects of pH are interpreted in terms of particle/particle interactions leading to flocculation which is demonstrated to be an essential prerequisite for flotation of small particles approaching colloidal size range with the typically 1-2mm bubbles produced in the cell. Regions in a flotation cell where hydrodynamic conditions permit flocculation are identified by an analysis of pulp flow based on a distributed shear rate model. The effects of initial solid concentration on recovery and grade are interpreted in terms of floc/bubble collision frequency. Influence of floc breakup and solid drainage on pulp phase and recovery kinetics, and product grade is discussed. Pulp phase kinetics are analysed on the basis of rate-distributed species model. The selective nature of froth drainage is demonstrated by a series of kinetic experiments using different froth heights. Air flowrate can influence both pulp phase kinetics and froth drainage. These effects are studied independently by conducting two sets of experiments - one with a negligible depth of froth and the other with a deep froth. An analysis of flow and rupture forces in the froth leads to identification of two distinct zones where different floc breakup and drainage mechanisms exist. On this basis a three-phase model, consisting of a mixed pulp phase and two mixed froth phases, is developed and used to predict froth effects on flotation kinetics and selectivity.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available