Abstract
Experiments have been conducted in which the charges on particles and bubbles in a flotation process have been measured. The particles were polystyrene latices of diameters between 4 and 20 μm. The bubbles were of mean diameter 53 μm. A cationic surfactant was used to promote flotation, and the charge on the particles and bubbles was controlled by addition of sodium sulphate solution. To measure the charge on bubbles, they were generated electrolytically in a glass electrophoresis cell so that they rose vertically up a “stationary level” in the cell, while at the same time moving sideways under the action of a horizontal potential gradient. The horizontal velocity, taken with the known potential gradient, gave the electromobility. The bubbles were found to carry the same sign as the particles (positive) and under the same electrolyte concentrations, the change on the particles and bubbles was approximately the same. Experimentally determined rate constants for flotation were found to depend strongly on the bubble and particle charge, decreasing by an order of magnitude as the charge increased from 30 to 60 mv. The data were well correlated by the equation: −1n ( k p / d p 1.5) = 3.9 + 0.116 U EU B where k p is the rate constant (min −1), d p , is the particle diameter (μm) and U E, U B are the electromobilities (μm/s/V/cm) of the particle and bubble respectively.
Published Version
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