The Research On Test And Preparation Of Carirer Of Oolitic Hematite Deep Reduction

The Al and Fe in the high alumina Oolitic hematite can be separated in the preliminarystudy of the depth reduction-dry magnetic separation. The process of the Al-Fe separation issimple, and the product of reduced iron can be used into the steel-making links directly, whichhas the value of industrial promotion. However, the high cost of taking pure graphite crucible ashigh-temperature carrier was not applied to the actual production line. Therefore, a low-costcarrier to have reduction process test must be found in order to reduce the cost.In this study, the high-temperature carrier in the process of high alumina oolitic hematitereduction as well as inspected applied performance in the process of preparing carrier wasinvestigated. The preparation and inspection of carrier in the depth reduction and reactionmechanism and process of hematite was investigated by means of XRD.The tests of Carrier preparation showed that refractory crucible can meet requirements ofthe depth reduction carrier when the ratio of flint （1to3mm） is37%, the flint （0.083to1mm） is33%, Guangxi clay is10%, the flint powder （0.083mm） is20%.When reduction temperatureis1350℃, reducing agent amount is29%, reduction time is110min, the grade of reduced ironproduct can get to92.14%, recovery can get to72.92%, the content of A_l2O₃can get to1.06%after the process of depth reduction-dry magnetic separation. Which can achieve the separationbasically. The clay crucible scrap which separated from slag by crushing and classification canserve as the raw material0.083mm to3mm coarse-grained level to reuse and recycle.The carrier can meet the requirements of high temperature reduction carrier, whereasdefects are still remain. The clay crucible tests showed that: it needs to increase dosage ofpulverized coal and prolong reduction time to achieve the same separation effect of aluminumand iron using graphite crucible. The main reason is the difference in heat transfer coefficient,the reduction process of clay crucible is slow, so it can change the style of heat transfer toimprove the affection.XRD analysis of clay crucible indicated that, the main compose of clay crucible is mulliteand cristobalite SiO₂,then A_l2O₃. The infiltration of FeO has been found in clay crucible contactwith slag, FeO react with crucible component generated FeO·A_l2O₃·SiO₂. The inferences drawndiscussion of depth reduction process is that conventional reduction reaction changed hematite toFeO, it can react with other silica alumina minerals in system to generate low-temperature meltbecause of its strong fusion effect, then FeO was reductive by C and precipitated from eutecticsubstance gradually to metallic iron after CaO replace it in this system.