Abstract: The iron grade of a magnetite concentrate is 56.14%,the content of S is 9.18%,and 95.75% sulfur is in form of pyrrhotite.In order to reach the target of sulfur content ＜1% in iron concentrate,the experiment of iron increase and sulfur reduction in magnetite concentrate was carried out according to the principle of grinding - low intensity magnetic separation-flotation.The results show that the iron concentrate with Fe grade 67.39% and S content 0.80%，can be obtained by grinding (-0.043 mm 85%)-one roughing one cleaning low intensity magnetic separation for desilicication-one roughing two cleaning reverse flotation desulfurization,also high-iron sulfur concentrate with iron grade of 62.54% and 17.50% can be obtained.Which provides a technical reference for iron increase and sulfur reduction of this kind of high sulfur magnetite concentrate.

Key words: Pyrrhotite, Low intensity magnetic separation, Desulfuration by flotation