Effect of solids on pulp and froth properties in flotation

Abstract

Froth flotation is a widely used process of particle separation exploiting differences in surface properties. It is important to point out that overall flotation performance (grade and recovery) is a consequence of the quality and quantity of the solid particles collected from the pulp phase, transported into the froth phase, and surviving as bubble-particle aggregates into the overflow. This work will focus on studying these phenomena and will incorporate the effects of particle hydrophobicities in the 3-phase system. Solids are classed as either hydrophilic non-sulphide gangue (e.g. silica, talc), hydrophilic sulphide (e.g. pyrite), or hydrophobic sulphide (e.g. sphalerite). Talc is a surface-active species of gangue that has been shown to behave differently from silica (frother adsorbs on the surface of talc particles). Both are common components of ores and will be studied in detail. The focus of this work is to investigate the role of solids on pulp hydrodynamics, froth bubble coalescence intensity, water overflow rate with solids present, and in particular, the interactions between solids, frother and gas on the gas dispersion parameters. The results show that in the pulp zone there is no effect of solids on bubble size and gas holdup; in the froth zone, although hydrophilic particles solely do not effect on the water overflow rate, hydrophobic particles produce higher intensity of rates on water overflow and bubble coalescence, and many be attributed to the water reattachment.

Keywords

flotation / frothers / bubble size / coalescence / gas holdup / hydrophobicity

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