Adsorption and flotation characteristics of hexagonal and monoclinic pyrrhotite

This study has been performed to better understand the flotation behaviour of pyrrhotite by quantifying the combined effect of crystal structure and chemical composition. Effect of these variables on flotability of pyrrhotite has not been clearly established to date due to the difficulty of obtaining pure samples of natural hexagonal and natural monoclinic pyrrhotite. Results will help to optimize those cases which are involved with either flotation or depression of pyrrhotite.;In the current research, oxidation of natural pyrrhotite together with difficulties of preparing pure natural samples of monoclinic and hexagonal pyrrhotite were of the main concern, therefore it was decided to synthesize pyrrhotite of each type under controlled laboratory conditions.;Using synthesized pyrrhotite and potassium amyl xanthate, adsorption tests were performed to evaluate the adsorption differences between hexagonal and monoclinic pyrrhotite. Results of these tests show that the adsorption of amyl xanthate on pyrrhotite of any type depends on the solution pH. While monoclinic pyrrhotite shows higher adsorption at pH 7.0 and 8.5, this trend changes at pH 10.0, at which hexagonal pyrrhotite showed better adsorption. Also in this stage xanthate adsorption was evaluated in presence of NaCN and CuSO;Flotation tests using a modified Hallimond tube have been performed to find the flotability differences of the two types of pyrrhotite along with the effect of CuSO;Adsorption and flotation tests using a natural monoclinic sample were performed in later stages which helped toward a better understanding of the behaviour of this mineral in real flotation circuits along with the effect of oxidation and impurities.