Agglomerate flotation of fine oxide particles

This paper presents experimental data on using both flocculants and surfactants for aggregation and flotation of fines. The work has been performed with water suspensions of two oxides, ZnO and MgO. Conventional flotation collectors (sodium oleate (SOL), sodium dodecyl sulphate (SDS) and cetyltrimethylammoniurn bromide (CTAB)) were used. Commercial high molecular weight polymers (MAGNAFLOC 1440, MAGNAFLOC E-10 and MAGNAFLOC 3 5 1) were the flocculants used. Adsorption isotherms of surfactants adsorbing onto the two oxides were determined at natural pH. Adsorption density was the greatest with sodium oleate. Zeta potential measurements indicated that addition of the cationic surfactant caused a positive increase of the zeta potential. The positive zeta potential of MgO decreased with increased anionic surfactant concentration. A decrease in stability indicated that the ZnO suspension pretreated with anionic surfactants caused the formation of larger floes when the cationic flocculant (MAGNAFLOC 1440) was added. Similar observations were obtained for a MgO suspension pretreated with anionic surfactants and reacted with the nonionic flocculant, MAGNAFLOC 351. The negative charged collector (SDS) appears to be good collector for ZnO floc flotation when hydrophobic floes are created by the combination of SDS and either cationic or nonionic flocculants. (C) 2003 Elsevier B.V. All tights reserved.