Slag adjusting and furnace protecting method for controlling rising of converter bottom and furnace wall slag deposition

Abstract

The invention belongs to the technical field of steelmaking and provides a slag adjusting and slag splashing furnace protecting method for controlling rising of a converter bottom and furnace wall slag deposition, solving the problems that the effective volume is reduced and the center of gravity of a furnace body shifts as slag stacked at the converter bottom rises and slag deposits at the lining of the furnace wall when the traditional slag splashing furnace protecting process is adopted. The method provided by the invention is characterized by adopting a two-step slag adjusting method, primary slag adjusting is carried out before molten steel is tapped, a boric sludge-magnesia slag adjusting agent is added into a furnace to reduce the viscosity of the slag, slag deposition at the lining of the unilateral furnace wall and slagging at the converter bottom in the tapping process can be prevented, the slag remaining and no steel remaining operation is adopted in the follow-up tapping process; and secondary slag adjusting is carried out after tapping, namely a magnesia carbon slag adjusting agent (coke powder and material containing magnesium oxide) is added into the slag remained in the furnace, and then the slag splashing slag protecting process is carried out. By adopting the method provided by the invention, the rising of the converter bottom and thickening of slag depositedon the furnace wall can be controlled, the thickness uniformity of the furnace wall can be guaranteed, and the slag splashing furnace protecting effect is obviously improved, thus the service life ofthe lining of a converter can be greatly prolonged.

Description

technical field [0001] The invention belongs to the field of iron and steel smelting, and particularly relates to a slag adjustment and furnace protection method for controlling the rising of the bottom of the converter and the accumulation of slag on the furnace wall in the converter steelmaking process. Background technique [0002] American LTV Steel Company first invented the converter slag splash protection method, which is to leave part of the final slag after the converter is tapped, and add an appropriate amount of slag adjusting agent to make the slag have a suitable viscosity and high refractoriness, and then The slag is sprayed with high-pressure nitrogen, so that the slag sputters and adheres to the furnace wall to form a new refractory and anti-corrosion layer, thereby achieving the purpose of protecting the furnace lining and increasing the furnace life; generally speaking, the furnace life is very long when the furnace is not protected by slag splash At least ...

AI Technical Summary

Problems solved by technology

[0003] In the process of slag splashing to protect the furnace, the slagging agent added to the converter is generally MgO and reducing agent. MgO can increase the viscosity and sintering point of the slag (that is, refractoriness), and the reducing agent plays the role of reducing iron oxide in the slag, which also improves The viscosity of the slag and the melting point of the slag, the viscosity of the slag after conditioning is high, which is beneficial to the slag hanging on the furnace wall, and the content of MgO in the slag after the slag adjustment is high, and the refractoriness is high; but there are also corresponding problems after the slag adjustment: the first problem is that Bottom accumulation of slag leads to the rise of the furnace bottom, which will cause the molten pool of the steelmaking furnace to rise, reduce the effective volume, and easily cause accidents such as overflow of steel slag and splashing; the second problem is that the slag accumulation on the side of the furnace wall leads to serious thickening of the furnace wall At the same time, the furnace wall on the tapping side becomes thinner, which affects the effect of slag splashing and the life of the converter. The fluidity is lost, and the high-pressure nitrogen gas is not fully sputtered to the furnace wall, but accumulates at the bottom of the furnace, or the slag has solidified when it reaches the furnace wall due to its high melting point, and cannot effectively adhere; it causes the furnace wall on the side where the slag is poured to thicken The reason is also that during the tapping process, since the temperature of the furnace wall on the slag dumping side is lower than the melting point of the slag, sticky slag accumulates. In addition, after the slag is splashed to protect the furnace, the converter is tilted to the slag dumping side for charging, which also causes the slag to accumulate on the slag dumping side. , that is, the furnace wall on the slag dumping side becomes thicker, while the furnace wall on the tapping side becomes thinner

[0004] Therefore, the reasons for the rise of slag accumulation at the bottom of the furnace and the thickening of slag accumulation on the furnace wall at the slag dumping side after adopting the slag splashing protection technology in the current converter can be attributed to the fact that a large amount of MgO was added to the slag adjusting agent at one time, and the slag in the slag was not increased. High content of iron oxide reduction leads to high melting point of slag and premature loss of fluidity, so it is difficult to be sputtered by high-pressure nitrogen to the furnace wall and form effective adhesion. A common problem caused by a series of factors such as expansion, extended tapping time, low temperature tapping to improve the quality of molten steel, and increasing the amount of MgO in the slag adjuster to increase the melting point of the slag splashing material.

[0005] In the prior art, the Chinese Invention Patent (Application No.: 03118577.0, Invention Name: A Method for Controlling Slag Sputtering at the Bottom of Converter) discloses a method of adjusting slag by using fluorite and controlling the content of magnesium oxide in the slag below 9%. , this method is similar to the furnace washing process. When a large amount of fluorite is used and the content of magnesium oxide in the slag is low and the content of iron oxide is high, the residue can be removed, but the furnace lining is severely eroded, and the effect of slag splashing and the life of the furnace lining cannot be guaranteed.

[0006] Therefore, it is necessary to study the corresponding slag adjustment process and slag splashing control technology in view of the problems of rising furnace bottom slag accumulation and thickening slag accumulation on one side furnace wall in the current large-capacity converter steelmaking