The Role of the Collector in Froth Flotation

Htin, Kyaw (1950) The Role of the Collector in Froth Flotation. PhD thesis, University of Glasgow.

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The importance of the polar-non-polar structure in the collector molecule is explained and a review is made of the present state of knowledge regarding the mechanism of collection in froth flotation. Using the bubble column, the froth stabilities of the lower fatty acids, which possess low collecting power, are compared and the results discussed with respect to the concentration at the air-liquid interface. Preliminary flotation tests are carried out on the variation in recovery of barytes with time of collection, rate of air flow, pulp density, and particles size, in a laboratory flotation cell to obtain the optimum conditions for later experiments. Tests on flotation of purified natural barytes with fatty acids and sodium soaps indicate that a complete monolayer of the collector is not necessary for maximum flotation and that adsorption of acid anion and not the formation of barium salt of the acid is responsible for collection. Physical adsorption of the fatty acid anion takes place with the hydrogen ions as counter ions. The effect of pH on flotation with caprylic acid, sodium caprylace, and lauric acid, is studied. The presence of the anions, hydroxyl, carbonate, and sulphate ions, is found to depress the flotation while the cations, barium ions, bring about activation. Hydrogen and ferric ions, however, depress the flotation. The part played by these ions is discussed. An investigation is made of the adsorption of ferric ions on natural barytes and pure barium sulphate. From the findings, a hypothesis on the mode of the adsorption and its relation to the depressing action, is put forward. Flotation of pure barium sulphate with sodium laurate is compared with that of natural barytes using the Hallimond Tube. Exploratory tests are done on the adsorption of the lower fatty acids on pyrites, silica, and barytes. The pH and the potentiometric titration methods indicate unimolecular adsorption of these acids on pyrites and barytes. The nitrogen adsorption method, Rigden's water permeability method, and the Lea and Nurse air permeability method are used for measuring the surface areas of the powders tested. The applicability of these three methods to flotation research is discussed.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Chemical engineering
Date of Award: 1950
Depositing User: Enlighten Team
Unique ID: glathesis:1950-78817
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 30 Jan 2020 14:51
Last Modified: 30 Jan 2020 14:51

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