Hydrophobic Flocculation of Galena Fines in Aqueous Suspensions.

The hydrophobic flocculation of galena fines induced by potassium amyl xanthate (PAX) in aqueous suspensions has been studied using laser diffraction, electrophoretic light scattering, contact angle, and microflotation measurements. The measurements were performed on <2 µm, 2-5 µm, 5-10 µm, and <30 µm size galena by varying several parameters, including PAX concentration, pH, original particle size, kerosene concentration, and suspension stirring. The experimental results have demonstrated that the hydrophobic flocculation was closely correlated with the particle hydrophobicity, but was not lowered upon increasing the particle surface charges due to PAX adsorption, which is contrary to the DLVO theory. This flocculation has been observed to increase with a reduction of the original particle size and an increase in kerosene concentration, and to require sufficient stirring strength and magnitudes of kinetic energy input to achieve the maximum aggregation degree. From the microflotation results, it has been found that the flotation response of galena fines is markedly improved due to the formation of hydrophobic flocs, suggesting that floc flotation is a promising means to recover galena in the fine size range. Copyright 2000 Academic Press.