Research Of The Influence Of Al₂O₃/SiO₂on Sintered Ore Mineralization Characteristics And Metallurgical Properties

During Iron ore sintering process，the SiO₂and Al₂O₃content has great influenceto the type and quantity of sinter mineralogical phases. For high-basicity sinter, the mainphase is the calcium ferrite system. The more the phase in sintering ore, the better thestrength and metallurgical properties sintering ore has. When there is not Al₂O₃insintering ore, SiO₂is not involved in the formation of calcium ferrite system, and in thehigh temperature has reaction with the calcium ferrite, reduces the calcium ferritequantity. But when sintering ore contain Al₂O₃, SiO₂and Al₂O₃will react with thecalcium ferrite, forms a complicated calcium ferrite compound （SFCA）which has betterreducibility.The sintering ore will get more calcium ferrite phase and greatermetallurgical properties. The content of Al₂O₃in the calcium ferrite phase solid solutionis limited. There is a certain relationship between Al₂O₃and SiO₂. So it has great valueto study the impact of Al₂O₃/SiO₂ratio to the phase composition and metallurgicalproperties of sintering ore.In this paper, first the influence of fuel ratio, basicity and Al₂O₃/SiO₂ratio to thecold strength of sinter has been researched with the orthogonal test method under thecurrent ingredients scheme and parameter conditions of Shuicheng Iron&steel Co. Thendesign a set of single factor experiments to study the influence of different Al₂O₃/SiO₂ratio conditions to metallurgical properties and mineralogical changes of sintering ore.Obtains these results through this paper’s research: Under the experimentalcondition based on Shuicheng Iron&steel Co, when the Al₂O₃/SiO₂ratio is0.30, thesinter process get the highest yield rate, when the Al₂O₃/SiO₂ratio is bigger than0.40,the sinter yield rate presents the remarkable drop. When the basicity stay in2.0, the fuelratio is6.5%, and the Al₂O₃/SiO₂ratio is about0.30, the yield ratio achieves about80%.Falling strength index is best when the silicon aluminum is between0.3-0.35, mayachieve about84%.When the Al₂O₃/SiO₂ratio being bigger than0.40, the fallingstrength index significantly decreased with the Al₂O₃/SiO₂ratio increase. The impact ofAl₂O₃/SiO₂ratio to sintering ore reductibility and reduction disintegration property isvery obvious. When the Al₂O₃/SiO₂ratio is0.35-0.40, the sintering ore has highreductibility index（RI）. When the basicity is2.0, the fuel ratio is6.5%, when theAl₂O₃/SiO₂ratio is about0.35, the reductibility index achieves about92%. The reduction disintegration property （RDI3.15） is about67%. The mineralogical phaseanalysis of sintering ore showed: When Al₂O₃/SiO₂ratio is lower than0.30, thesintering ore contain fewer calcium aluminate, but more silicate phase, easy to form thesilicate glass phase. When the Al₂O₃/SiO₂ratio is about0.35, SiO₂and Al₂O₃melt intothe calcium ferrite during the sintering process to form a large number of SFCAstructure. When the Al₂O₃/SiO₂ratio is higher than0.35,with the rise of Al₂O₃/SiO₂ratio,the sinter holes and cracks increase and the Fe2O3phase is reduced faster, some of thegranular iron oxide is converted to sheet, silicate glass phase small increase.In summary, get the appropriate parameters of sintering mixture based on thecondition of Shuicheng Iron&steel Co. The appropriate basicity is about2.0, theappropriate fuel ratio is about6.5%and the Al₂O₃/SiO₂ratio is about0.35.