Hydrophobicity-hydrophilicity balance relationships for collectorless flotation of sulphide minerals

Abstract

Hydrophobicity-hydrophilicity balance relationships for self-induced and sodium sulfide-induced flotations of sulphide minerals have been established, through solvent extraction-chemical analysis of neutral sulphur (S°) on the surfaces, measurement of redox potential (E_pt) of flotation pulp, and flotation tests. They may be’indicated as [S°]/[OH⁻] and [S°]/([OH⁻]+[HS⁻]), respectively. The neutral suphur (S°) was considered to be responsible for the hydrophobicity, the amount ([S°]) of which was controlled byE_pt. The critical value of [S°] was proposed as a new concept. The hydrophilicity was contributed to OH⁻ ion for the self-induced flotation, and to both HS⁻ and OH⁻ ions for the Na₂S-induced flotation. At a given pH value, hydrophobicity and floatability increase with [S°]. For different pH values, a higher pH value results in stronger hydrophilicity, and hence the hydrophobicity and flotation require more [S°]. Lower pH values are in correspondence with the smaller [S°].

Keywords

hydrophobicity / hydrophilicity / balance / induction / flotation