Abstract
The effect of titanium dioxide, kaolin, calcium carbonate and talc on the properties of foams formed by sodium oleatelsodium stearate solutions and the flotation yield of these pigments in the presence of the same soaps have been investigated. In addition, the flotation of dispersed model coatings prepared from these pigments with styrene-butadiene and polyacrylate latexes was studied. The influence of coating colour composition and flotation chemicals (including silicate) was investigated using factorial experiments. The latexes strongly increase pigment floatability, but the effects are interrelated with the effects of other components in the coatings in a complex way. The flotation yield of the different pigments depend quite differently on the amounts of calcium and silicate added. This indicates that it may be possible to achieve flotation selectivity by proper design of flotation strategies. The factorial experiments also make it possible to draw some tentative conclusions with regard to mechanisms giving rise to the observed effects.
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