Refining Technology. Low Sulfur Steel Furnace

Literatures about the research situation and the advance of low sulfur steel have been reviewed,and in the paper,based on the iron pretreatment,converter smelting, secondary refining and fine refining slags controlled and so on,new technology about smelting process of low sulfur steel such as the technology of iron pretreatment, control technology of resulphurization,steel slag solidify,ladle slag flux modification and refining slag optimization etc,have been discussed.With the real production conditions of low sulfur steel in PZH Steel at present,the production processes have been improved and the new technology has been established.The CaO-Al₂O₃ base slags containing MgO,BaO,Na₂O,CaF₂ as auxiliary components are designd by quadratic orthogonal regression method.According to composition of the designed slags,both fusing point test and desulfuration trial have been completed.Based on the experimental results,mathematical models between composition and melting temperature,composition and sulfur patition ratio were established.Calculated results had good consistency with experimental data.The effects of composition on molten properties and sulfur distribution were discussed.By comprehensive consideration of physicochemical properties of slag in the study,the optimized composition of refining slag ought to be 2.5～3CaO/Al₂O₃,4%～5%MGO,10%～13%BaO,10%～13%CaF₂.Lastly,the new produce processes have been adopted in commercial test in Vanadium Recorery and Steelmaking Plant of PZH Steel,the result is the refining slag present low melting point,slagging swiftness and good spreadability.The results show that the molten steel ratio of desulphurization has heavy advance from the top to LF refining end,the average is 66.10%and the best mount up to 91%,and the sulphur of finished product is all less than 0.0066%～0.003%.The new process realizes deep reduction of sulphur effect.