Pyrrhotite is the most important gangue in nickel sulfate mines. Its presence not only produces distractions in upgrading circuits applying flotation but in smelter too by causing S02 emissions and thus environmental pollution. In this article micro flotation of pyrrhotite was studied using two pure synthetic samples applying a modified Halimond tube. Also to evaluate the effect of impurities a natural sample from Sudbury region in Canada was tested. Results show the different behavior
among samples while flotation parameters such as pH, concentration of sodium cyanide, presence of copper ions in pulp and oxidation vary. Based on the results, although applying an alkaline environment, intensive oxidation of the mineral samples and using sodium cyanide as depressant for pyrrhotite are P,Tesenting acceptable results to eliminate the mineral in
flotation stage; however, the degree of response is a function of crystallography and impurities. Pyrrhotite flotation in alkaline pH, while using 20 mg/I collector, resulted in a recovery between 20 and 30% depending on type of the sample. Applying oxidation at the same pH lessons the recovery for about 10% in all cases. In the other hand, sodium cyanide is able to reduce the recovery for about 5% for all samples. Activating pyrrhotite samples by copper sulfate resulted in a similar behavior in all three types of pyrrhotite.
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