Flotometric analysis of the collectorless flotation of sulphide materials

Abstract

Collectorless flotation of different size fractions of sulphides and sulphur was conducted in a monobubble-type Hallimond tube. Flotation tests were carried out with sulphides of different origins at their natural pH and natural redox potential in distilled water. The floatabilities of sulphides were compared to the floatabilities of hydrophobic elemental sulphur and hydrophilic quartz and magnetite, taking into account the density of the investigated solids. It was established that chalcopyrite, pyrite, galena and copper (I) sulphide floated as well, or almost as well, as elemental sulphur. This indicated the presence of sulphur or a layer of sulphur-excess sulphide on the surface of these solids during flotation. The floatability of another galena and another pyrite, sphalerite, iron (II) sulphide and nickel (II) sulphide was found to be equal, or almost equal, to the mechanical carry-over of hydrophilic quartz and magnetite, most likely because of hydrophilicity of a fresh sulphide surface or the presence of such hydrophilic products as metal hydroxides or metal sulphuroxy compounds. It was also suggested that the so-called parameter L of the “flotometric equation” can be used to characterize the flotation properties of sulphides. The flotometric equation has the form a 50 ϱ′ = L 50, where a 50 is the maximum diameter of the particle which can be successfully floated, while ϱ′ is the density of the solid in water.