Inorganic Electrolytes on the Efficacy of a Carboxymethyl Cellulose as a Coagulant for Talc: Implications for Talc Depression in Flotation

摘要

Polymers such as polysaccharides are added into froth flotation circuits to render gangue or non-valuable minerals hydrophilic and these as a consequence are prevented from reporting to the concentrate. Recent flotation research on PGM ores suggests that changes in water quality, specifically inorganic electrolytes and their ionic strengths may affect the coagulative-flocculative nature of solid mineral particles in flotation pulps in the presence of polysaccharides such as carboxymethyl cellulose (CMC). This could well have considerable implications on the hydrophilicity of gangue minerals and therefore the concentrate grades owing to interactions between process water electrolytes, the polysaccharides and solid mineral particles. Thus this study considers the effect of ionic strength of process water and specific ions on the coagulation of talc particles using CMC. This investigation has shown that the settling time of talc particles decreased in increasing ionic strength of process water. It was shown that when talc particles were contained in Ca~(2+) and Mg~(2+) electrolyte solutions, their settling time was shorter compared to when they were present in Na+ electrolyte solutions. The reduction in settling time implies that there was an improvement in the hydrophilicity and coagulation of talc particles in concentrated electrolyte solutions.