Research On Dephosphorization And Dephosphorization Products Of High Phosphorus Silicon-Manganese Alloy

Silicon-manganese alloy has a large and wide application range.It is commonly used deoxidation and alloying additive for steelmaking.With the development of China's steel industry,manganese alloy production is not only severely over-supplied,but also due to the generally low grade of manganese ore in China,the production of phosphorus in manganese-silicon alloy The impurity content is seriously exceeded.P in the silicon-manganese alloy will pollute the molten steel,reducing the quality of the steel.Therefore,controlling the phosphorus content in the Si-Mn alloy and making it national standard is an important issue in the field of ferroalloys.This topic mainly explores the problem of excessive phosphorus content in silicon-manganese alloys in Chongqing Chengkou and Xiushan.The slag phase diagram was constructed by thermodynamic software such as FACTSage,and a reasonable experimental scheme was developed.The high-phosphorus manganese-silicon alloy was subjected to reductive dephosphorization experiment using"induction furnace and silicon molybdenum furnace";XRD,ICP,XPS,SEM and other detection methods were adopted.The mechanism of reduction and dephosphorization of silico-manganese alloy by Al-based dephosphorization agent,the mechanism of alloy pulverization after dephosphorization and the existence form of phosphide in CaO-SiO₂-Al₂O₃ and CaO-SiO₂-MgO slag system are discussed.The thesis research has the following conclusions:With the increase of the amount of Al-based dephosphorization agent,the dephosphorization rate gradually increases.As the basicity increases,the dephosphorization efficiency gradually increases.The interaction of the gas with the microcracks eventually leads to alloy pulverization.Compared with the microstructure of the alloy after dephosphorization of high and low alkalinity slag,the alloy is denser after high basicity dephosphorization,and the powdering is less.The results on the reduction and dephosphorization of silico-manganese alloy under CaO-SiO₂-MgO slag system shows that the dephosphorization rate decreases with the increase of MgO content,With the increase of basicity,the dephosphorization rate is increased.With the increase of CaO/MgO,the dephosphorization rate is increased.The XRD analysis of the dephosphorization terminal slag and the valence state analysis of the P element in the slag confirmed that the dephosphorization product was AlP and calculated by Harris texture coefficient,and the preferred orientation of AlP in the dephosphorization final slag was?111?.The atomic mismatch between the MnSi?110?plane and the?111?plane boundary of AlP is calculated,and the atomic mismatch between the two plane boundary is 6.72%,which indicates that there is a certain interface coherent relationship between the two.AlP can serve as a heterogeneous nucleation substrate for the MnSi phase during crystallization.