A comparison of the flotation of ore from the Merensky Reef after wet and dry grinding

The effect of dry and wet grinding on the flotation of complex sulfide ores from the Merensky Reef in South Africa was investigated. Topographical examination of the ground particle surfaces by scanning electron and atomic force microscopy showed that the dry ground samples had relatively rough particle surfaces with a high concentration of microstructural defects, while the wet ground samples had smoother, cleaner surfaces. As a result, the activated particle surfaces from the dry ground ore accelerated the dissolution of the particles, as well as the adsorption of reagents onto the particle surfaces. The dry ground samples exhibited more stable, higher loaded froths and faster flotation kinetics, owing to the activated particle surfaces. High intensity conditioning of the dry ground ores prior to flotation could improve flotation by cleaning the particle surfaces through high shear force fields in the pulp, Moreover, by combining dry and wet grinding, the kinetics, as well as the final grades and recoveries of the sulfides, could be improved. (C) 2000 Elsevier Science B.V. All rights reserved.