Research and application of new technology for ultra-deep dephosphorization in large-scale converter
LÜ Yanchun1,2, ZHOU Deguang3, ZHU Guosen1, ZHU Zhiyuan1, WANG Guolian3, LI Haibo1, LIU Yang1
1. Research Institute of Technology, Shougang Group Co., Ltd., Beijing 100043, China; 2. Engineering Research Center of Energy Steel, Beijing 100043, China; 3. Shougang Jingtang United Iron and Steel Co.,Ltd.,Tangshan 063210, Hebei, China
Abstract：In order to realize the high efficiency production of the ultra-clean steel with low-phosphorus, the efficient smelting technology of ultra-low phosphorus steel based on low MgO (2.5%≤w(MgO) ≤4.0%), low MnO (w(MnO)≤1.5%), high alkalinity (R≥6) and ultra-high phosphorus distribution coefficient (LP≥1 500) was studied and developed. It is found that reducing the content of MgO and MnO in steel slag and increasing the alkalinity of steel slag can greatly improve the balance phosphorus distribution coefficient LPbal of converter end slag to more than 1 500. By optimizing the burden structure in the early stage of smelting, the oxidation of steel slag is improved, and high-speed slag melting is realized, the average phosphorus content reaches 3.47% and the FeO content is controlled at 17%-20% in semi-steel slag. Through calculation and optimization of the slag-dumping model and automatic control, the rapid, efficient and stable slag pouring of semi-steel is realized, and the amount of slag pouring at the end of semi-steel is controlled above 35%. Through the efficient stirring of molten pool, the ratio of actual production slag steel phosphorus distribution coefficient LPact to theoretical balance phosphorus distribution coefficient LPbal is about 0.81 on average. Low phosphorus steel smelting technology such as low temperature tapping is adopted to realize batch, stable and efficient production of converter tapping with the minimum phosphorus mass fraction of 0.000 38%, the average phosphorus mass fraction of 0.000 73% and 0.001 05% for converter tapping and finished product respectively by double slag process smelting. The average converter smelting cycle is 42 min. In this study, the ultra-deep dephosphorization technology of converter steelmaking is first discovered and applied,which has a good reference value and technical application prospect for low phosphorus clean steel smelting.
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LÜ Yanchun, ZHOU Deguang, ZHU Guosen, ZHU Zhiyuan, WANG Guolian, LI Haibo, LIU Yang. Research and application of new technology for ultra-deep dephosphorization in large-scale converter[J]. China Metallurgy, 2023, 33(10): 73-80.
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2023, Vol. 33 
