The influence of polymeric dispersants on sericite-chalcocite particle interactions in aqueous media
Date
2009
Authors
He, M.
Addai Mensah, J.
Beattie, D.
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Journal article
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Chemical Engineering Journal, 2009; 152(2-3):471-479
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Abstract
Unexpected sericite–chalcocite mineral particles’ hetero-aggregation occurs under aqueous processing conditions where both minerals display negative zeta potentials. In this study, the use of anionic copolymers (carboxylate- versus sulphonate-substituted) as dispersants to suppress the hetero-aggregation behaviour was investigated in the pH range 5–9. Both polymers showed strong substrate and pH- dependent adsorption and electrokinetic potential characteristics onto both minerals. The adsorptionpropensity was considerably higher onto chalcocite than sericite particles and dramatically accentuatedat pH 5 for the former due to leached electropositive Cu(II) species’ surface activation effect. At high polymer dosages (>1.5 g kg−1 solid) leading to plateau adsorption density, the magnitude of both mineral particles’ zeta potential increased to a maximum. Furthermore, the adsorbed polymer layer dominated the interfacial chemistry that showed subtle mineral phase and pH dependency. The concomitant particle interactions reflected a marked reduction of dispersion shear yield stress and the suppression ofsericite–chalcocite particulate adsorption. Electro-steric repulsive forces are believed to be responsible for the dispersing mechanism. Both polymers displayed similar, high dispersing efficacy at dosages>1.5 g kg−1 solid for sericite–chalcocite mix dispersions, regardless of the pH.
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Crown Copyright 2009 Published by Elsevier B.V.