Steel-making method for prolonging service life of bottom-blowing oxygen converter through CO2

Abstract

The invention belongs to the field of the metallurgy technology, and relates to a steel-making method for prolonging the service life of a bottom-blowing oxygen converter through CO2. According to the method, mixed gas of O2 and CO2 serves as bottom main blowing gas, mixed gas of hydrocarbon and CO2 serves as protective gas, and the CO2 mixing proportion in the bottom-blowing mixed gas of O2 and CO2 and the mixed gas of hydrocarbon and CO2 is controlled according to different smelting stages of the bottom-blowing oxygen converter; and by means of the characteristics that CO2 reacts with iron and carbon to absorb heat, and CO2 does not contaminate molten steel, the outlet temperature of a bottom-blowing nozzle is reduced, consumption of hydrocarbon is reduced, the quality of molten steel is improved, and therefore the service life of the bottom-blowing oxygen converter is prolonged, and the smelting cost is reduced. The steel-making method is suitable for the bottom-blowing oxygen converter of 30-350 tons; and by means of the steel-making method, the bottom service life of the bottom-blowing oxygen converter can be prolonged by 300-600, the smelting cost of steel per ton can be reduced by 2-3 yuan, and the end-point molten steel carbon-oxygen equilibrium can be reduced by 0.0002-0.0004.

Description

technical field [0001] The invention belongs to the field of metallurgical technology, in particular to a 2 A steelmaking method for extending the life of a bottom-blown oxygen converter. Background technique [0002] The bottom-blown oxygen converter has greatly improved the stirring conditions of the converter, the slag-steel reaction is close to the equilibrium state, and the carbon can be removed to the low-carbon field under the condition that the slag (FeO) basically does not increase, and is suitable for mass production of low-carbon steel ;The combination of bottom-blown oxygen and bottom-blown slagging agent (such as lime powder) can efficiently remove phosphorus and sulfur in molten iron, and reduce the consumption of steel and slagging materials; the bottom-blown oxygen converter has excellent metallurgical effects Incomparable advantages of conventional top-bottom combined blowing converter. [0003] However, due to the large flow of oxygen injected at the bott...

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Problems solved by technology

[0003] However, due to the large flow of oxygen injected at the bottom, the molten pool is strongly stirred, and the reaction between oxygen and Si, Mn, Fe, C and other elements is violently exothermic. The temperature of the reaction zone above the bottom blowing pure oxygen nozzle can reach 2000~2400 °C It poses a very serious threat to the bottom blowing nozzle and the surrounding lining bricks; mixing a certain proportion of nitrogen in the bottom blowing oxygen, or replacing pure oxygen with dry air can help reduce the bottom temperature of the furnace, but it will cause a large amount of nitrogen in the molten steel, and the end point The nitrogen content in molten steel exceeds the standard, which cannot meet the smelting needs, and the nitrogen mixing process is not feasible; therefore, the bottom-blown oxygen converter in the prior art still mainly injects pure oxygen, resulting in a low furnace bottom life, currently only 1000~2000 furnaces

[0004] At present, the method of injecting hydrocarbons into the annular gap is usually used to protect the bottom-blowing nozzle by utilizing the heat-absorbing properties of hydrocarbons at high temperatures. However, hydrocarbons are expensive, which increases the cost of steelmaking, and the injection of hydrocarbons It will lead to hydrogenation of molten steel; mixing nitrogen in hydrocarbons will cause nitrogenation in molten steel, mixing argon will lead to increased costs, and the cooling effect of nitrogen and argon is not good, so only hydrocarbons can be used in the prior art as Protective gas, resulting in large consumption of hydrocarbons and high smelting costs