An Investigation on Removing Sulfur from Hamadan Magnetite Concentrate

In the concentration plant of Hamadan, magnetite concentrate is produced by low intensity magnetic separators (LIMS). As a result, 47% of feed sulfur was recovered in magnetite concentrate, keeping sulfur at higher content than that is commercially desired. Mineralogical investigations revealed that Pyrrhotite and Pyrite are the most abundant sulfur minerals, respectively. Davis Tube investigations indicated that by decreasing magnetic field intensity and particles size, sulfur content  in magnetite concentrate could be decreased to 1.7%,  which is still much more than desired.  Further investigations were performed using flotation method and based on statistical design. Modelling and analysis of design data revealed that the dosage of collector and activator and their interaction have statistically significant effects on the process with 95% confidence level. İt was found that the optimum condition of removing sulfur would be achieved using 1100 g/t of Potassium amyl xanthate (collector), 200 g/t of copper sulfate (activator), 65 of g/t MIBC and 65 g/t of A65 (frothers), at pH=6 and solid percent of 45%. At the given condition, 98% of sulfur in magnetite concentrate (2.3% sulfur) was successfully removed and the product with 0.04% sulfur was obtained.