Study On Preparing High Quality Iron Concentrate By Pyrite Cinder Mainly Made Of Hematite

It’s difficult to deal with pyrite cinder effectively for their different properties and complex composition. In this paper, magnetic roasting-grinding&magnetic separation-acid leaching process is put forward to prepare high quality iron concentrate with a kind of pyrite cinder of which TFe is53.51%and hematite content is47.67%.Tests show that through magnetic roasting during which Fe2O3transforms into Fe3O4that is strong magnetic, iron grade64.81%and iron recovery more than90%can be achieved by grinding&magnetic separation. At the same time, separation behaviors of iron-bearing mineral and impurities are studied during magnetic roasting-grinding&magnetic separation. Great changes of sulfur content of pyrite cinders have taken place, but the Pb, Zn, Cu content change little. Sulfur content is greatly reduced which is mainly in the form of sulfate dissolving into water during grinding, and followed by sulfate decomposition in the process of roasting. Because Pb、Zn、Cu mainly exist in form of plumbojarosite, franklinite, combined copper oxide respectively which are insoluble in water and closely join with iron-bearing mineral, it’s difficult to separate during magnetic separation.Results of Removing Pb, Zn, Cu and S in the magnetic concentrate by acid leaching show that significantly reduce of decrease impurities content such as Pb, Cu, S and improvement of iron grade can be obtained under the conditions of hydrochloric acid mass fraction of5%, pulp density of30%, leaching time of20min and leaching temperature of20℃. After leaching, Pb removal rate is over60%, Cu removal rate is over50%, S content is below0.15%, and TFe is up to66.24%. Due to the removal of metal impurity and the gangue minerals, the iron concentrate grade gets further improve. Leachate treatment is carried out as well. There are19figures,28tables and59references in this paper.