One-step Direct Reduction Of Vanadium-titanium Magnetite Coal-based Melting Study

As an important source of iron,vanadium,titanium and other elements,vanadium-titanium magnetite has a relatively high comprehensive utilization value.At present,there are many problems in main stream vanadium extraction processes,such as blast furnace method and direct reduction with long technological process,low resource utilization rate,and unfriendly environmental,which constrain the development of vanadium-titanium magnetite smelting.Aiming at this situation,Qi Tao research team of the Institute of Process Sciences of the Chinese Academy of Sciences proposed a one-step direct reduction-melting separation process for vanadium-titanium magnetite coal base.Through the process,the effective separation and comprehensive utilization of vanadium,titanium and iron elements were realized.Based on a thorough investigation of the vanadium-titanium magnetite smelting and vanadium extraction literature.In this paper,vanadium-titanium magnetite was used as raw material,NaOH as additive,and anthracite as reducing agent to carry out research on one-step direct reduction melting separation process of vanadium-titanium magnetite coal base.The vanadium-containing pig iron and vanadium-rich titanium slag are obtained by this process.Vanadium-containing pig iron can be used for further steelmaking,and vanadium-rich titanium slag is used in water immersion experiments,and the following conclusions have been made:?1?The chemical reactions of vanadium-titanium magnetite in this process were calculated and analyzed by software HSC Chemistry.It can be seen that,within the temperature range covered in this paper,the reduction reaction of iron oxide and the sodium oxidation reaction of vanadium oxide occur spontaneously,and the soluble sodium vanadate stay stable,but the calcium magnesium vanadate is easily reduced at high temperature,which provides a theoretical basis for the process of reduction-melting separation and leaching vanadium extraction.?2?The optimum process parameters of the one-step direct reduction melting separation of vanadium-titanium magnetite coal base were studied.It was discovered that under the optimal condition where it was in the air atmosphere,the additive was50%NaOH,the reduction time was 4 hours,the reduction temperature was 1300?,and mol?C/Fe?=2.6,The content of V₂O₅ is 1.34%and TiO₂ is 7.70%in vanadium rich titanium slag can be obtained,together with metal iron which is the high quality vanadium-containing pig iron with Fe accounting for 95.53%,V 0.47%,Ti 0.003%,S0.046%,and P 0.015%,and better achieve the effective separation of vanadium,titanium and iron.?3?Through the above research on the process conditions,it was found that proper temperature rise,time extension,and increases in the amount of reducing agent and additives can enhance the melting effect of slag iron and the sodium conversion process of vanadium and titanium.The main phases in the reducing slag include CaTiO₃,NaAlSiO₄,Na₆Al₄Si₄O₁₇,and vanadium and titanium are mainly exist in them.?4?The optimum process parameters of water immersed vanadium rich slag were studied.The particle size of vanadium-titanium slag is about 5?m,the leaching temperature is 90?,the leaching time is 60 mins,the liquid solid ratio is 2:1,and the stirring speed is 300r·min^-1.Under such optimal condition,the water immersion experiment is carried out,and the leaching rate of V,Na and Ti elements is 83.36%,70.05%and 1.07%,and the titanium element is hardly leached.The effective leaching of vanadium is achieved and separate it from titanium.