The Technology And Mechanism Of Direct Reduction Magnetic Separation Of Titanium And Iron By The Embedding Method For Seashores Titanomagnetite

The seashores titanomagnetite?TTM?is plentiful and cheap mineral processing.However,the concentrates with low Fe grade and high TiO₂ content are obtained by traditional mineral processing techniques.These concentrates are difficult for smelting,and the titanium goes into slags resulting in a waste of titanium resources.According to the previous studies,coal-based direct reduction followed by magnetic separation is the most effective method to achieve separation of titanium and iron in TTM.But the ash in the coal went into the non-magnetic products?tiatanium products?which led to the low TiO₂ grade in titanium product.To address these problems and realize the recovery of iron and titanium,this study employs embedding direct reduction and magnetic separation to separate iron and titanium.The seashores TTM concentrates are pressed into pellets and then completely embedded into the coal to avoid the impact of coal ash and ensure excellent reduction conditions.The test samples came from Indonesian seashores TTM that was weak magnetic separated which the grade of Fe and TiO₂ contents are respectively 57.29 mass%and 11.42 mass%,this paper study the mechanism of separation of iron and titanium in seashores titanomagnetite by using embedding direct reduction followed by-magnetic separation systematically.Embedding direct reduction followed by magnetic separation was used to separate iron and titanium.The dosages and types of reductant and additives,reduction time,and reduction temperature were investigated.The results showed that,regardless of the addition of sodium sulfate or fluorite,Fe recovery in the direct reduction iron?DRI?and TiO₂ grade in titanium products both are low,which did not meet the research objectives.When the bitumite was used as reductant,the better DRI and titanium product were obtained than used anthracite or coke as reductant.The Fe recovery,Fe grade in DRI and TiO₂ grade in titanium product were improved by extended reduction time.The best result was obtained,and the DRI with Fe grade of 90.48%,Fe recovery of 90.12%,and TiO₂ content of 0.93%were obtained.Titanium products with TiO₂ grade of 45.58 mass%and TiO₂ recovery of 95.35 mass%were obtained.The mechanisms have been ascertained by XRD analysis,SEM-EDS analysis and flue gas analysis.The results showed that adding sodium sulfate or fluorite not only introduced impurities,but also deteriorated reduction condition.The reductant with better gasification reactivity was benenitical to the reduction of the TTM.The better gasification reactivity reductant could provide the sufficient reduction atmosphere,and inhibit the generation of fayalite.However,the worse gasification reactivity reductant could not provide the sufficient reduction atmosphere,resulting in the generation of fayalite.And these reductants not only decreased the Fe recovery,but also generated more liquid phase which stoped the diffusion of reduction gas and inhibitied the TTM reduction.According to the research of reduction time and temperature,the results showed that the Mg exsit as isomorphism in TTM,and the reduction sequence of TTM is suggested as follows:Fe₂?Mg,Fe?0.75Ti_0.25O₄??Fe,Mg?₂TiO₄??Fe,Mg?TiO₃ ??Fe,Mg?Ti₂O₅? MgTi₂O₅+Ti₃O₅?...