The invention discloses a low-cost slagging and dephosphorizing technique for high-
phosphorus molten iron through converter
smelting. The slagging and dephosphorizing technique comprises the steps of
slag remaining and splashing, primary charging, primary blowing, turning down and deslagging, secondary feeding, secondary blowing, and terminal control and steel tapping, all final
slag is reserved for
slag splashing after steel tapping, and the steps are repeated circularly. The obtained final slag comprises, 35-48% of CaO, 8-14% of MgO, 8-13% of SiO2, 10.20-18.50% of TFe, and 2.50-5.60% of P2O5, and the
alkalinity is 2.5-6. By the adoption of the slagging and dephosphorizing technique,
smelting of the high-
phosphorus molten iron is integrally optimized; materials, such as high-cost slagging agents,
magnesite pellets and light-burned magnesian limestone, are partially or completely replaced by low-cost and environment-friendly sintered and returned mines and raw magnesian limestone, and a corresponding
technological system is set; and the extra heat is balanced while smooth dephosphorizing is guaranteed, the slag oxidation, the P2O5 content and the final slag MgO content are improved, the slagging cost is reduced by over 8 yuan / t while a furnace lining is protected and the dephosphorizing effect is achieved, the furnace age is prolonged from 12000 times to 15000 times, and the application value and popularization value are high.