Method for reducing loss of molten iron during slag removal

Abstract

The invention relates to a method for reducing the loss of molten iron during slag removal. The method comprises the following steps: step 1, setting a risk reservation value according to a requirement on sulfur in finished smelted tapped steel; step 2, determining a target desulfurization level for molten iron pretreatment; step 3, calculating the total mass of sulfur in slag after desulfurization of molten iron and the mass of sulfur in residual slag after permitted slag removal so as to further determine a residual slag proportion after slag removal; step 4, determining a theoretical slag removal weight interval; step 5, carrying out early-stage slag removal operation, and when a slag removal amount reaches 50% to 70% of the lower limit of the theoretical slag removal weight interval, carrying out air blowing to drive away slag and later slag removal operation, wherein a camera is employed for monitoring during the operation; step 6, acquiring an actual slag area proportion, comparing the actual slag area proportion with a target residual slag area proportion, and terminating slag removal when the two proportions are identical; and step 7, acquiring actual slag removal weight and determining whether the actual slag removal weight in the theoretical slag removal weight interval. The method provided by the invention has the advantage o that the smelting rate of sulfur reaches100%.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for reducing the loss of slag scraping of molten iron. Background technique [0002] For most steel types, sulfur element is a harmful element, which can reduce the processing performance of steel, deteriorate the welding performance of steel, cause "hot embrittlement" and high temperature cracking of steel, and also significantly reduce the plasticity of steel. Therefore, in iron and steel smelting, it is generally required that the sulfur in molten steel be as low as possible. Pre-desulfurization before converter smelting is an indispensable technical means for smelting low-sulfur clean steel. The desulfurization products generated by the pre-desulfurization of molten iron will all float into the molten iron slag, causing the sulfur content of the molten iron slag to increase with the increase of the sulfur content of the molten iron. Generally speaking...

AI Technical Summary

Problems solved by technology

In the prior art, the residual amount of molten iron after desulfurization and molten iron slag removal has a great influence on the sulfur content at the end of the converter, and because a large amount of scrap steel and slag-making auxiliary materials need to be added during the converter smelting process, scrap steel and slag-making auxiliary materials The sulfur content of the converter will also have a greater impact on the sulfur content at the end of the converter, and because these effects cannot be removed during the converter smelting process, it is necessary to reduce the amount of scrap steel and slagging auxiliary materials by reducing the amount of slag in the molten iron. Influence on sulfur at converter end point

[0003] In the process of smelting low-sulfur steel grades, the conventional method of removing slag from molten iron is mainly to remove the slag from molten iron or simply determine the grade of slag removal based on the sulfur content of the finished product of the smelted steel. Influence of sulfur and other factors on the sulfur content at the end point of converter

In the process of removing slag from molten iron, the slag removed usually carries about 50% of the molten iron, which results in higher metal consumption and higher costs

At the same time, since the slag removal operation is manual, there are great differences in the amount of iron in the slag removal process, and the operator lacks a quantitative concept of how much slag is removed, and can only operate based on experience

If the amount of slag removal is insufficient, it will cause resulfurization during steelmaking, which will affect the quality of molten steel

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