A low-cost slagging and dephosphorization process for converter smelting high-phosphorus molten iron

Abstract

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.

Description

technical field [0001] The invention belongs to the technical field of slagging dephosphorization in converter smelting, and in particular relates to a low-cost slagging dephosphorization process for smelting high-phosphorus molten iron in a converter. Background technique [0002] Kunming Iron and Steel Co., Ltd. of Wuhan Iron and Steel Group uses self-produced low-cost high-phosphorus ore for ironmaking. The phosphorus content of the high-phosphorus hot metal produced is as high as 0.35-0.80%, with an average of 0.62%. It is already at the leading level of industrialized mass production at home and abroad. The aggravation of homogeneous competition and the needs of enterprises to survive need to continuously reduce the cost of slagging and dephosphorization. The present invention investigates and analyzes the traditional slagging process of converter smelting, and finds that the traditional slagging process has the following problems: [0003] (1) Due to the short tapping...

AI Technical Summary

Problems solved by technology

[0006] (4) In the original process, the timing of adding slag material, the timing of turning down the furnace, and the control of the gun position are unreasonable. For example, the magnesite balls are added too early and the double slag is poured out too early, and the effect of slag removal is difficult to reflect when the slag agent is added too early. Problems such as premature timing of double slag pouring and insufficient deep blowing time at the end point

[0007] Aiming at the problems of excess heat, poor slag melting effect, high slag material consumption and high slagging cost in smelting high-phosphorus molten iron in the above-mentioned converter, the present invention aims to analyze, design and improve the smelting process operation system of each stage of smelting high-phosphorus molten iron in the converter, Propose a low-cost slagging dephosphorization process for smelting high-phosphorus molten iron in a converter to achieve smooth dephosphorization and effectively reduce the cost of comprehensive slagging