A Study of the Theoretical Principles of Froth Flotation

The present state of knowledge with regard to froth stability is reviewed and its importance in the froth flotation process stressed. The bubble column is taken as the ideal froth flotation machine. The variables governing the formation of a dynamic column of froth are studied. The height of the column increases linearly with pressure of applied air and the resistance of the porous plate is always varying. The effect of change of temperature is greatest at low temperatures. Bike naan's law connecting froth volume with air flow is criticised. A new empirical law is suggested which provides constants for characterising froth stabilities. The froth column is subjected to dimensional analysis and two new equations are derived connecting height of froth column with air flow. The concentration of frothing agent for maximum froth stability is evaluated for the lower monohydric alcohols and the implications of the results discussed. The importance of Pine Oil as a flotation agent is analysed. The froth stabilities of aqueous solutions of three Pine Oil samples are compared with each other and with aqueous solutions of the chemical components of the Pine Oil complex. Terpineol, Bornaol, Camphor, and Fenchyl Alcohol are true "frothers" and Anethole and Dipentene are "stabilizers." A stabiliser is believed to act through its ability to spread on the bubble wall. Flotation tests are carried out on a Coal/limestone mixture to compare the relative effectiveness of Pine Oil and its components. Traces of undissolved oil caused by adding the reagent dropwise to the flotation machine in moderate concentration gives increased recovery of Coal. Adsorption of frother on the Coal surface is suspected. The shape of the "recovery curve" in a batch flotation test is discussed