Flotation of sulfide minerals with the use of a cationic collector

In the flotation of Zn-Pb ores, sphalerite is floated following activation with copper sulfate. In this type of sulfide ore, pyrite is commonly treated as a gangue and poor selectivity between sphalerite and pyrite/quartz is often reported. But pyrite may also appear in association with gold and flotation of such auriferous sulfides is of great importance in many countries such as South Africa and Australia. In the cationic flotation of sulfide ores with dodecyl amine, sphalerite can be floated while depressing quartz and pyrite. While in a well-aerated pulp in the presence of lime (especially after oxidation with H2O2) the cationic flotation of pyrite is depressed, oxidation of pyrite in the presence of Na2S makes it floatable with amines even in a very alkaline environment.