Converter dephosphorizing and steelmaking method

Abstract

The invention provides a converter dephosphorizing and steelmaking method. The method comprises the following steps of: a, adding slag making materials which consist of active lime, high-magnesium lime and a composite slagging agent into a converter molten pool; blowing and slagging by a dephosphorizing oxygen lance oxygen blowing process and an inert gas bottom blowing process to remove phosphorus in molten steel; and pouring 60 to 80 percent of slag out when the molten pool temperature in a converter is between 1,420 and 1,450 DEG C, the alkalinity of the slag is between 2.0 and 2.5 and the total iron content in the slag is between 10 and 15 weight percent; and b, adding the slag making materials into the converter molten pool; blowing and slagging by a normal oxygen lance oxygen blowing process and the inert gas bottom blowing process to further remove the phosphorus in the molten steel; pouring the slag out when the molten pool temperature in the converter is between 1,680 and 1,700 DEG C, the alkalinity of the slag is between 3.2 and 4.2 and the total iron content in the slag is between 16 and 23 weight percent to obtain the molten steel with the phosphorus element content of not more than 0.009 weight percent. By the method, the dephosphorizing efficiency and the dephosphorizing effect of the converter are improved, and the production cost is reduced.

Description

technical field [0001] The invention relates to the technical field of converter steelmaking, and more specifically, relates to a converter dephosphorization steelmaking method. Background technique [0002] For enterprises using vanadium-titanium ore resources for smelting and production, in order to ensure the effective use of vanadium resources, it is necessary to extract vanadium and desulfurize before steelmaking. The molten steel obtained after vanadium-containing molten iron is desulfurized and vanadium-extracted is usually called semi-steel. In this semi-steel, the mass percentage of carbon is 3.4% to 4.0%, and the content of heat-generating slag-forming elements such as silicon and manganese is trace. And the mass percent content of sulfur in the semi-steel is controlled within 0.015%. However, due to no dephosphorization treatment, the mass percentage of phosphorus in the semi-steel is usually 0.060% to 0.080%, which leads to the conversion of the semi-steel after...

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Problems solved by technology

However, this method also has the following disadvantages: adding a deep dephosphorization agent to the ladle in advance has strict requirements on the control of the oxygen content of the molten steel. If the oxygen content of the tapping is too high, the ladle may be "shot" during the tapping process or after the tapping is completed. Phenomena, there are certain safety hazards; deep dephosphorization agent must be added to the ladle before and after tapping and weak deoxidation treatment of molten steel, which makes the dephosphorization treatment time too long and slows down the production rhythm

However, this method has the following disadvantages: when the phosphorus content in the furnace is too high, it is difficult to control the final phosphorus within 0.006% by using the single slag method;

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