INTERACTIONS BETWEEN ZINC-SULFIDE PARTICLES UNDER FLOTATION-RELATED CONDITIONS

Rheological investigations of dispersions of spherical synthetic zinc sulphide particles have been conducted under flotation-related conditi ons and correlated with interparticle force-distance measurements usin g ''colloid probe'' atomic force microscopy. The interparticle interac tions observed are discussed in terms of zinc sulphide surface chemist ry; the latter was characterised by electrokinetic and X-ray photoelec tron spectroscopic measurements. At pH < pH(iep) of zinc sulphide ther e is clear evidence of a hydrophobic attraction, in addition to electr ostatic and van der Waals forces, affecting interparticle interactions . The presence of copper(II) ions at pH 4 resulted in increased Bingha m yield values and interparticle cohesive forces, whereas at pH 10 no such attractive interactions were observed. These findings are discuss ed in the context of copper(II) ion activation of sphalerite in flotat ion practice.