Hydrophobic interaction in flocculation and flotation 1. Hydrophobic flocculation of fine mineral particles in aqueous solution

Abstract

In this paper the flocculation behavior of fine mineral particles rendered hydrophobic by the surfactant and the mechanism of hydrophobic flocculation are discussed. Experimental studies with quartz, rhodochrosite, hematite and rutile show that changes in wettability of mineral surface significantly affects the stability of fine particle suspensions. The hydrophobization of particle surface is often accompanied by a distinct flocculation which may by no means be interpreted by Derjaguin—Landau—Verwey—Overbeek (DLVO) theory. The theoretical approach to hydrophobic flocculation and calculation related to the quartz—amine system as well as to the rhodochrosite—oleate system shows that the potential energy of hydrophobic interaction between mineral particles rendered hydrophobic by surfactant far exceeds that resulting from double layer or van der Waals interactions. Flocculation induced by hydrophobic interaction between fine mineral particles plays a predominant role in many techniques of fine particle separation, such as shear flocculation, emulsion flotation, carrier flotation, spherical agglomeration, etc.