Effects of metal ions on flotation of Sulfide minerals

Abstract

Flotation is a mineral processing method that using deference of Hydrophilicity/hydrophobicity. In flotation, air bubbles are induced to the slurry that contains ground ore and water. Hydrophobic minerals are attached to air bubbles and floated to the surface of the slurry, and hydrophilic minerals remains in the slurry. Hydrophilic/hydrophobic property of minerals can be controlled by chemical reagents: Collectors like xanthate adsorbs on Cu and Pb sulfide minerals and make the mineral surface hydrophobic. If ore contains several minerals, interaction of the minerals on the floatation is observed: Sphalerite has less affinity to xanthate and low floatability. When anglesite exists with sphalerite, however, Pb2+ released from anglesite react with sphalerite and PbS-like compounds is formed on the surface, which has a high affinity to xanthate, resulting in the high floatability of sphalerite. Using a model sample containing galena, sphalerite, pyrite, anglesite, pyrrhotite and barite, the effects of Zn2+ on the flotation of the minerals was investigated with DOW#250 as frother, potassium amyl xanthate as collector, Na2SO3 as depressant, H2SO4 and NaOH as pH adjuster. When 500 ppm of Zn2+ was added, floatability of sphalerite was suppressed. The suppression mechanism of sphalerite by Zn2+ is discussed based on the experimental results.