Safe and high-efficient low-silicon molten-ion blowing process

Abstract

The invention discloses a safe and efficient low-silicon molten iron blowing process, which belongs to the technical field of converter smelting. Fill the converter with 80.0~90.0% by weight of low-silicon molten iron and the remaining steel scrap. In the early stage of blowing 0~2min, the position of the oxygen lance is set at 140~160cm, and the constant pressure of oxygen supply is 0.84~0.88MPa. The flow rate is 26000~28000m3 / h. Add slag after the blowing starts, and the dosage is 17.00~25.00kg of lime, 13.50~19.00kg of light burnt dolomite, 0~12.00kg of iron ore, 0~80.00kg of pig iron per ton of molten iron, and raise the gun position to 155 ~175cm. At the end of blowing, lower the position of the gun to 110-120cm for 85-95 seconds, and the blowing time for the whole process of oxygen supply reaches 13-15 minutes, and then lifts the gun and dumps the slag. The blowing process of the present invention is beneficial to the early slag melting in the blowing process of the low-silicon molten iron, the slag is completely melted and the slag is melted well, and the dephosphorization efficiency is obviously improved. The slag completely covers the molten steel surface, which is beneficial to reduce the sticking problem of oxygen lance, furnace mouth, fume hood, etc. caused by splashing, reduces the loss of steel material, reduces the intensity of maintenance and cleaning work, and is conducive to saving costs and improving It is safe in production and has good promotion and application value.

Description

technical field [0001] The invention belongs to the technical field of converter smelting, and in particular relates to a safe and efficient low-silicon molten iron blowing process with good slag melting effect, high dephosphorization efficiency, less splashing. Background technique [0002] Due to the fluctuation of raw materials used in blast furnaces and the reduction of coke ratio in ironmaking, the silicon content of molten iron supplied from blast furnaces in ironworks to steelmaking plants for converter smelting often fluctuates greatly, which puts higher requirements on the converter smelting process. Especially when the silicon content of molten iron is on the low side, it brings a lot of technical difficulties to the converter smelting process. First of all, during the smelting process of low-silicon molten iron, the decarburization reaction is advanced, and the oxidation of carbon is prior to the oxidation of silicon, and the SiO in the slag 2 It is difficult to ...

AI Technical Summary

Problems solved by technology

First of all, during the smelting process of low-silicon molten iron, the decarburization reaction is advanced, and the oxidation of carbon is prior to the oxidation of silicon, and the SiO in the slag 2 Dicalcium silicate that appears earlier in the initial slag hinders the melting of lime, making slagging difficult in the early stage of blowing and poor dephosphorization effect

Secondly, with the progress of the blowing process, the FeO content in the slag gradually decreases, which is not conducive to the melting of lime, and it will also cause difficulty in slag melting. The slag is easy to "return dry" and the fluidity becomes poor.

Thirdly, the low-silicon iron slag layer is too thin, the amount is too small, the molten steel surface is not well covered, the degree of slag foaming is reduced, and the metal splash is serious, which further causes serious accidents such as oxygen lance sticking to steel, which not only increases the processing cost, It also affects the smooth progress of production

In addition, the silicon content in molten iron is low, and the CO gas content rises rapidly after converter blowing and ignition, while the O 2 The content drops slowly, which can easily lead to flying guns or even detonation