Shear flocculation of fine hematite particles and correlation between flocculation, flotation and contact angle

This paper presents a study on the shear flocculation of fine (38 mu m) hematite using dodecylamine acetate and Aero 801 (a mixture of petroleum sulfonate and mineral oil) as collectors. The effects of pH, collector concentration and stirrer speed were investigated. In addition, contact angle and flotation recoveries of the mineral were determined at different pH values. The results indicated that shear flocculation was possible over a wide pH range with the amine, whereas it was restricted to a narrow. pH range (2.5-3.5) with Aero 801. This was attributed to the better hydrophobicity of the mineral, indicated by higher flotation recoveries and contact angles within the same ranges. (C) 1997 Published by Elsevier Science S.A.