Application Of Multi-components Coupling Reaction Model In Slag-metal Reaction Of Niobium-bearing Molten Iron

Niobium resources in China is rich, Baotou Bayan Obo Multi-metallic inter-grown ore occupies about95%niobium resource reserves of whole country. But due to the symbiotic relationship is complex and niobium-containing in niobium-bearing ore is low, lead to a lot of difficulties in use of the mineral resources rational and efficient. Niobium-bearing molten iron is rich in niobium resource, in order to use this part of niobium resource efficient and rational, researchers conducted a large number of experimental and technological research, and made certain achievements. The slag-metal reaction system in smelting process of niobium-bearing molten iron contains multiple chemical reactions, these reactions occur simultaneously, coupled and influenced each other, and this made the reaction system become very complicated.In this paper, a niobium-oxide direct alloying model has been build based on the basic idea of multi-components coupling reaction model; Combining the oxygen-transfer model in the process of bottom-blowing oxygen with multi-components coupling reaction model, the model of desiliconization and niobium conservation process in the intermediate frequency induction electric furnace with bottom-blowing oxygen device had been build. The model was compiled by C++language and simulated by the experiments of direct alloying with niobium-bearing slag and the experiments of desiliconization and niobium conservation with niobium-bearing molten iron by bottom-blowing oxygen respectively. The multi-components coupling reaction model was applied to the slag-metal reaction process of niobium-bearing molten iron. And the dynamics process of slag-metal reactions in niobium-bearing molten iron has been described by the model which was build in present work.Through the calculation of the model, the conclusions are as follows:(1)The mathematical models of direct alloying process with niobium oxide and the experiments of desiliconization and niobium conservation by bottom-blowing oxygen to the Nb-bearing hot metal are certain applicable to the dynamics process of slag-metal reactions in niobium-bearing molten iron.(2)In process of direct alloying with niobium-bearing slag, the initial [Si] content in molten steel and (%FeO)/(%Nb2O5) are influence the reduction rate of (Nb2O5) and the [Nb] content in molten steel at equilibrium state significantly, however, the influence of the reaction temperature in bath is weak relatively.(3)Compared with the experiment without adding slag, adding slagging agent which contained CaO(60%)-CaF2(25%)-SiO2(15%) in desiliconization and niobium conservation process can suppress the oxidation of niobium more effective and increase the separate degree of silicon and niobium by oxiding.(4)In the process of experiment with adding slag, the oxygen content at interface is increase slowly before niobium start oxide and always less than the oxygen content in liquid iron, the reaction system is in unequilibrium in whole blowing time. When the element niobium start to oxide,[Si] content in liquid iron is about0.081%, the oxygen content at interface is about0.66×10-3%.