Depression of Flotation-Sensitive Silicates Using Polymeric Anion Active Reagents

The authors investigate depression of talc in its monomineral flotation with polymeric anion active reagents: carboxy methyl starch and carboxy methyl cellulose (CMS and CMC, respectively), sulfonates, as well as compounds with polyvalent cations of metals. Sodium polystyrene sulfonate with molecular mass of 106 kg/kmol is more effective in talc depression than sulfonates of smaller molecular mass, but gives way to CMS and CMC. Cations of Mg and Al at concentration of 2.5 mg/l increase efficiency of talc depression with sodium polystyrene sulfonate by 4%. The further rise in concentration of cations of metals weakens depression of talc. Addition of sodium polystyrene sulfonate up to concentration of 250 mg/l changes electrokinetic potential of talc from –20 to –32 mV. As compared with CMS and CMC, polymeric sulfonates have lesser adsorption affinity to talc. The authors propose two alternative mechanisms of interaction between polymeric sulfonates and basal surface of talc: without polyvalent cations of metals and with preliminary addition of these cations.