Research Of Dephosphorization And Desulphurization In Melted Iron Or Molten Steel Containing Niobium

In order to realize comprehensive utilization for niobium resources of Baiyun Ebo Mine,"Direct Alloying method"is put forward for high strength law alloying steel-including niobium by conventional working procedure with blast furnace used to niobium-contain molten iron and multi-function converter for steelmaking. There are two methods for it: blast furnace used to niobium-contain molten iron, molten iron preprocessed to dephosphorization and desulphurization and multi-function converter to decarburization and niobium conservation; blast furnace used to niobium-contain molten iron, molten iron preprocessed to desulphurization, multi-function converter to decarburization and niobium conservation and molten steel preprocessed to reduced dephosphorization. In this paper, it contains fundamental research of dephosphorization and desulphurization in melted iron and molten steel containing niobium.For one thing, the present application and the development tendency round the world of the hot metal pretreatment are introduced, the trait and necessary of it are analyzed and the research results which have been accomplished about the pretreatment of hot metal field is summarized.This topic has completed the series research work by following:By thermodynamic analysis, at the premise ofαNb₂O₅=1, the thermodynamics of dephosphorization and niobium conservation with BaO is possible. the oxidative process with BaCO₃—BaF₂ slag in molten iron containing niobium shows that Nb and P are oxided at the same time and Nb is oxided at priority of P. Further reduction of Nb oxidation experiment and Nb oxidation, P oxidation synthesis experiment show that: Complex compounds of Nb and P in slag can lowerαNb₂O₅ of slag. This phenomenon is the Fundamental cause of producing Nb oxidation. The experiment on reducing dephosphorization with Ca has been carried out. It shows that, The effect of dephosphorization is not obvious. The experiment of desulfurization with Mg has been carried out. It shows that, The effect of desulfurization is obvious and the rate of desulfurization is increase with the increase of the dosage of Mg. desulfurization with Mg can not affect the content of Nb. By the integrated experiment of dephosphorization and desulfurization with CeO₂-CaF₂-CaCl₂, we find that CeO2 is also a kind of effective desulfurization agents, but can not dephosphorize.