JPH10251716A - Mud material in blast furnace and method for protecting furnace buttom of blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the wearing of a brick at the side wall parts below a molten iron tapping hole near the tapping hole easily thinning the remained thickness of brick by containing a specific content of vanadium in mud material used to the plugging of the tapping hole in a blast furnace. SOLUTION: The vanadium content in the mud material is made to 5-50wt.%. In the case of exceeding 50% in this content, the material change of the mud is too much and the plugging function of the iron tapping is not displayed. In the case of being not more than 5% in this content, since the rising allowance of viscosity of molten iron near the molten iron tapping hole is small, the forming effect of consisting layer is too small. Further, the vanadium is made to the formation of metallic vanadium and/or iron-vanadium alloy to easily progress the melting into the molten iron. Then, in the blast furnace having 10 or more years of the working term, the wearing caused by abrasion and erosion of the brick at the side wall part below the tapping hole near the tapping hole is progressed, and therefore, it is desirable to take the above countermeasure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mud material used for closing a tap hole of a blast furnace and a method for protecting a blast furnace bottom.

[0002]

2. Description of the Related Art Prolonging the life of a blast furnace has the effect of reducing the cost of hot metal, and various measures have been taken. Especially in recent years, blast furnace facilities have been improved, specifically, furnace body cooling systems have been strengthened (eg, stave cooling capacity, cooling board cooling capacity, tuyere cooling capacity, etc.), and repair techniques for damaged furnace body parts have been improved. Accordingly, the life of the furnace body has been dramatically extended, and in recent years, the average value of the results of the furnace life has been approaching 15 years.

At present, the rate-determining parts that determine the repair of a blast furnace that has extended its life are the lower part of the shaft and the bottom wall of the furnace. The lower part of the shaft is no longer the rate limiting part due to the progress of the intermediate repair technology, and most blast furnaces have the remaining brick thickness on the furnace bottom side wall as the rate limiting part of the repair.

Techniques for suppressing the reduction of the remaining brick thickness of the furnace bottom side wall include a method of enhancing cooling of the furnace bottom side wall,
Titanium oxide is blown from the tuyere above the place where the remaining brick thickness is thin, and a viscous layer of hot metal is formed inside the furnace of the brick to protect it. The tuyere above the place where the brick remaining thickness is thin Method of blinding the air, narrowing the air volume of the tuyere above the place where the brick residual thickness is thin with a branch pipe air flow control valve, and forming a viscous layer at the place where the brick residual thickness is thin by cooling off Have been.

In Japanese Patent Application Laid-Open No. 6-256822, a mixed material of metallic titanium or iron-titanium alloy and a viscous substance is injected from a tap hole of a blast furnace, and the viscosity near the tap hole is increased to increase the viscosity of the viscous layer. There is disclosed a technique for suppressing the reduction of the remaining thickness of the side wall brick near the tap hole.

[0006]

Generally speaking, even if the furnace bottom side wall is used, the remaining brick thickness is reduced in the side wall below the tap hole near the tap hole. Therefore, even if the method of strengthening the cooling of the furnace bottom side wall portion is implemented, the cooling capacity is limited due to the structure of the equipment. In addition to the above measures, protection by forming a viscous layer of hot metal with high viscosity by charging titanium oxide from the furnace top or blowing titanium oxide from the tuyere above the brick where the remaining thickness is thin A method of narrowing or blinding the tuyere diameter at a portion where the brick has a small remaining thickness, and a method of restricting the amount of air blown at the tuyere above a portion where the brick has a small thickness by a branch pipe air flow control valve.

However, in any of the methods, there is a limit to the suppression of wear of the side wall brick below the taphole near the taphole where the remaining brick thickness tends to be thin. In particular, in the method of charging the titanium oxide from the furnace top, it is necessary to increase the charging amount in order to suppress the wear at the place where the remaining brick thickness is small near the taphole. However, if the charging amount is excessive, there is a large possibility that the viscosity of the hot metal in the entire hearth increases and the liquid permeability of the hearth deteriorates, so the charging amount has an upper limit and the effect of suppressing brick wear cannot be expected much. .

The technique disclosed in Japanese Patent Application Laid-Open No. 6-256822 has an effect of suppressing a reduction in the remaining thickness of the side wall brick near the taphole. However, the increase in hot metal viscosity due to the dissolution of 1% by weight of titanium in hot metal is about 20%, and the effect of increasing the hot metal viscosity by applying the present technology is small.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a mud material for blocking a taphole of a blast furnace comprising at least one of tar, pitch, graphite, and clay, which comprises vanadium. It is characterized by containing 5 to 50% by weight. Further, in the above, it is characterized in that the vanadium is a metal vanadium and / or an iron vanadium alloy. Also, when closing the tap hole of the blast furnace,
A mud material containing 5 to 50% by weight of vanadium is used.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a mud used for closing a tap hole of a blast furnace in order to suppress brick wear on a side wall portion below the tap hole near the tap hole where the remaining brick thickness tends to be thin. An additive is added to the material to greatly increase the viscosity of the hot metal.

The effect of increasing the viscosity of hot metal by dissolving 1% by weight of vanadium in the hot metal is as large as slightly over 40%, and more than twice the effect of increasing the viscosity of hot metal when a mud containing titanium is used. Therefore, when the present invention is applied, a viscous layer near the taphole can be easily formed as compared with the case where a mud to which titanium is added is used.

Here, when the content of vanadium in the mud material of the present invention is more than 50%, the material change of the mud becomes too large, and the tapping function is not exhibited. Further, the content of vanadium in the mud material of the present invention is 5%.
If the amount is less than the weight percentage, the increase in the viscosity of the hot metal near the taphole is small, and the viscous layer forming effect near the taphole is too small. Further, the reason why vanadium is in the form of metal vanadium and / or iron vanadium alloy is to facilitate the dissolution in hot metal.

In a blast furnace having an operation period of 10 years or more,
Since the wear and erosion of the brick on the side wall portion below the taphole near the taphole is progressing, it is desirable to always provide the method of the present invention.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A blast furnace to which the present invention is applied is a blast furnace having a furnace diameter of less than 9 m and a 2,000 m ³ class internal volume, having two tap holes, and this blast furnace has been operating for 13 years since the current ignition. Has passed. As shown in FIG. 1, in the present blast furnace, from the time when the operation period has passed 10 years, the brick thickness on the bottom wall of the furnace including the viscous layer becomes 1000 mm or less, and the viscous layer once or twice a year. Disappeared and the temperature of the furnace wall brick below the taphole near the taphole rose to 250 to 280 ° C.

After the elapse of 11 years, the method of the present invention was carried out, and a mud material containing 20% by weight of vanadium was used for closing the tap hole. As a result, the temperature of the brick wall below the tap hole near the tap hole was reduced. Began to gradually decrease, and after 5 months, the temperature became around 125 ° C. and the fluctuation became small.

As a result, in the conventional method, the temporary wind is shut off for 1 to 2 hours to blind the tuyere above the place where the temperature of the furnace wall brick is increased, or to shut off the wind for several hours to several tens of hours. However, it was necessary to take measures to promote the formation of a viscous layer, but these treatments could be completely eliminated after application of the method of the present invention.

[0017]

By the practice of the present invention, there is no phenomenon that the temperature of the side wall brick below the taphole near the taphole rises, and the wear of the side wall brick below the taphole near the taphole is reduced. In addition to eliminating production cuts due to wind breaks as a countermeasure, it has also made it possible to extend the life of the blast furnace.

[Brief description of the drawings]

FIG. 1 is a diagram showing a transition of a maximum value of a side wall brick temperature below a taphole near a taphole before and after implementation of the present invention.

Claims (3)

[Claims] 1. A blast furnace mud material comprising at least one of tar, pitch, graphite, and clay for use in closing a taphole of a blast furnace, comprising 5 to 50% by weight of vanadium. 2. The method according to claim 1, wherein the vanadium is metallic vanadium and / or vanadium.
The mud material for a blast furnace according to claim 1, wherein the mud material is an iron vanadium alloy. 3. A method for protecting a blast furnace bottom, comprising using a mud material containing 5 to 50% by weight of vanadium when closing a tap hole of the blast furnace.