Effects of organics in water on the flotation of copper and molybdenum sulphide minerals.

Process water used in mineral processing plants is usually a blend of different water supplies, including fresh water, bore and surface waters, waters from treated or untreated sewage plants and industrial effluents, and recycled waters. The quality and more particularly their constituents may impact flotation performance. The objective of this study is to investigate the effect of various natural acidic organic polymers, such as humic and fulvic acids, and tannic acid on the flotation of Cu and Mo sulphides in alkaline conditions (pH 9.3). Adsorption studies of these polymers on chalcopyrite and molybdenite were also conducted to interpret the flotation results. It was shown that Cu and Mo grades decreased with addition of humic, fulvic and tannic acid in that order, and the effect was more pronounced for molybdenite grade and recovery. UV-visible spectroscopy solution analysis also confirmed that these polymers were indeed adsorbed on the surface of molybdenite and chalcopyrite. The detrimental effect of organic materials in flotation is explained in terms of changes in froth characteristics, enhanced entrainment of fine particles, and a decrease in the overall hydrophobicity of the sulphide mineral surfaces, due to the adsorption of hydrophilic groups in these polymers which then prevent bubble-particle adhesion.
Process water used in mineral processing plants is usually a blend of different water supplies, including fresh water, bore and surface waters, waters from treated or untreated sewage plants and industrial effluents, and recycled waters. The quality and more particularly their constituents may impact flotation performance. The objective of this study is to investigate the effect of various natural acidic organic polymers, such as humic and fulvic acids, and tannic acid on the flotation of Cu and Mo sulphides in alkaline conditions (pH 9.3). Adsorption studies of these polymers on chalcopyrite and molybdenite were also conducted to interpret the flotation results. It was shown that Cu and Mo grades decreased with addition of humic, fulvic and tannic acid in that order, and the effect was more pronounced for molybdenite grade and recovery. UV-visible spectroscopy solution analysis also confirmed that these polymers were indeed adsorbed on the surface of molybdenite and chalcopyrite. The detrimental effect of organic materials in flotation is explained in terms of changes in froth characteristics, enhanced entrainment of fine particles, and a decrease in the overall hydrophobicity of the sulphide mineral surfaces, due to the adsorption of hydrophilic groups in these polymers which then prevent bubble-particle adhesion.