PETROGRAPHIC OBSERVATION ON HEMATITE PELLETS OF EAST-ANSHAN IRON ORE CONCENTRATE IN BLAST FURNACE SMELTING

Samples of low basicity hematite pellets made from East-Anshen iron ore con-centrate and charged a 100m~3 experimental blast furnace have been taken fromfive equalized points along diameter of furnace shaft at 6.5m below the burdenline during processing. A petrographic observation on mineralogical reactionsof the samples has been made in comparison with the industrial fluxed sinters sam-pled in the same manner. It was shown that the indirect reducing reaction oc-curs under temperatures above that of the pellet firing in all samples. The reduc-ing gases of the furnace atmosphere penetrate through the pores and gaps of thepellet and react with its liquid and solid phase substances. The behaviour of thereducing reaction in the pellets appears to be better than that of sinters owingto their different micro-porous structures. Since the pellets flow downward alongindividual path with various courses of reaction, six typical models of concentriclayer structure of them would be proposed. The iron oxides matx is bonded es-sentially by molten silicates of CaO-Al_2O_3-SiO_2 system formed at high tempera-ture and by other systems, e.g. CaO-FeO-SiO_2, etc. as well. The magnetizingphenomena of CaO-Fe_2O_3 system has also been obviously observed.