Measurements and analysis of xanthate chain length effect on bubble attachment to galena surfaces

초록

Although available flotation experiments show that sulphide flotation recovery increases with increasing xanthate chain length, quantitative analysis to reveal the underlying mechanisms is missing. Herein, we investigate the chain length effect by using a recently developed attachment apparatus and an advanced theory to determine and validate the attachment time of air bubbles to galena surfaces in solutions of ethyl, propyl, butyl and amyl xanthate collectors. Specifically, the attachment time was accurately determined from either transient force curves or transient film thickness of the bubble-surface attachment. The theory was based on the film drainage theory and colloidal forces, which include the advanced multilayer dispersion (van der Waals) interactions and the electrical double-layer interaction. The multilayer dispersion theory has allowed us to describe the effect of galena hydrophobicity induced by the xanthate chain length in terms of interfacial gas enrichment (IGE) on the bubble-surface attachment. The experimental results show that the attachment time is greatly affected by both the hydrophobicity and the bubble size, and agree with the theoretical results. Critically, it was possible to accurately quantify the attachment time of the hydmphobised galena surfaces to bubbles using the measured transient force curves and the advanced multilayer dispersion theory incorporating the IGE layer. Finally, this study made it possible to explain the effect of the hydrophobicity and bubble size on attachment time and provides the principle for the attachment mechanism of hydrophobic minerals to air bubbles.

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