Pretreatment process of desiliconization, dephosphorization and desulfurization of molten iron by kr-ob method

Abstract

The invention belongs to the field of iron and steel smelting, and specifically relates to a pretreatment process for desiliconization, dephosphorization and desulfurization of molten iron by using the KR‑OB method. On the basis of the KR method mechanical stirring device, a side oxygen blowing lance is added. The oxygen lance is located on the platform above the processing position. When it is in the oxygen blowing position, the vertical distance between the lance body and the column of the stirring head is 300mm, and the working stroke of the oxygen lance reaches 3000mm. The minimum distance between the nozzle of the gun head and the inner wall of the ladle on the opposite side is 600mm. When blowing oxygen, the position of the nozzle can be manually adjusted to avoid splashing of molten iron, and to ensure that the oxygen flow will not blow to the column or penetrate the molten iron to the inner lining of the ladle, causing The refractory material is severely corroded. Oxygen blowing desiliconization and dephosphorization of the present invention solves the problem of thermal energy loss of molten iron caused by adding a large amount of oxidized iron sheet to melt and absorb heat before, and the temperature of molten iron is increased by about 30-45°C compared with the latter, creating favorable dynamics and desulfurization for dephosphorization and desulfurization. Thermodynamic conditions, significantly improve the dephosphorization rate and desulfurization rate.

Description

technical field [0001] The invention relates to a pretreatment process of molten iron, in particular to a pretreatment process for desiliconization, dephosphorization and desulfurization of molten iron by using the KR-OB method, and belongs to the field of iron and steel smelting. Background technique [0002] With economic development and scientific and technological progress, the society's demand for special steel continues to grow, and the market sales of high-end products such as sheet steel, automobile sheet, home appliance sheet, silicon steel, and pipeline steel are gradually increasing. In order to improve the quality and performance of special steel, the requirements for the content of harmful elements P and S in various steel types are also stricter. At present, in order to meet the quality requirements of products, all steel mills first undergo dephosphorization and desulfurization treatment by molten iron pretreatment when smelting special steel. In order to mee...

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Problems solved by technology

[0004] When desiliconization and dephosphorization of molten iron by KR method, a large amount of iron oxide scale and slagging agent need to be added. The melting of these cold materials will absorb a large amount of heat of molten iron, resulting in a sharp drop in the temperature of molten iron

According to relevant research data, the drop of molten iron temperature will have the following adverse effects: ①Desulfurization treatment is an endothermic process, and too low temperature is not conducive to its thermodynamic conditions; The main restrictive link of the reaction, if the temperature is too low, the mass transfer coefficient of each reactant will be reduced, which is not conducive to the reaction; ③The temperature of the molten iron is too low, which will cause iron to stick to the bottom and wall of the bag, increase iron consumption, and cause the calorific value of the converter to be low Difficulty in smelting

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