JPH10185450A - Method for prolonging lifetime of ladle lining refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for prolonging the lifetime of the ladde lining refractory for reducing damage at the initial stage of operating by enhancing strength of hot refractory. SOLUTION: The method for prolonging the lifetime of the ladle lining refractory comprises the steps of supplying a gas containing magnesium vapor or magnesium chloride or a gas containing steam, carbon dioxide or oxygen into a ladle 1 to fully fill the ladle 1 with the gas, and then supplying the other gas into the ladle 1. The magnesium vapor or magnesium chloride gas is reacted with steam to precipitate magnesia in ores of an alumina magnesia castable to reinforce the refractory 7 of an operating surface side, thereby prolonging the lifetime of the ladle lining refractory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extending the life of a refractory lining a ladle.

[0002]

2. Description of the Related Art Generally, refractories lining a ladle include:
Alumina-magnesia castables are used. The castable construction is performed by a casting method. In order to remove water during the construction before use, the castable is heated and dried. The porosity after drying is quite large, about 16
%. Therefore, there is a problem that the inside of the refractory is more easily eroded through the pores. For example,
The slag enters the pores of the refractory and reacts,
Erosion of refractories proceeds.

Conventionally, there is no countermeasure against deterioration of the alumina / magnesia castable itself during heating, and a method of spraying a mixture of refractory powder and water to a damaged portion, that is, a dry spraying method, is known as a repair method during operation. ing. In addition, a thermal spraying method has been proposed.

[0004]

However, these prior arts are methods for repairing refractories during operation, and if these repairs are performed before heating, the drying of the base material is hindered and sufficient dehydration is not achieved. Will not be done. Further, even if repair is performed by these repair methods after drying, the quality of the base material itself cannot be improved.

The present invention has been made to solve the above problems, and provides a method for extending the life of a ladle-lined refractory which increases the strength of the refractory between heat and reduces damage at the start of operation. .

[0006]

According to the present invention, a gas containing magnesium vapor or magnesium chloride, or a gas containing water vapor, carbon dioxide or oxygen, is first prepared with the ladle opening closed. A method for extending the life of a ladle lining refractory, characterized in that one of the gases is supplied into the ladle to fill the ladle, and then the other gas is supplied to the ladle.

Here, the state in which the opening is closed is a state in which the gas supplied into the ladle can be prevented from leaking, and the type is not particularly limited. In addition, the gas containing magnesium vapor or magnesium chloride refers to a gas that does not react with magnesium vapor, magnesium chloride gas, or magnesium vapor or magnesium chloride, and is a gas obtained by diluting magnesium vapor or magnesium chloride gas. As the dilution gas, for example, N
₂ or Ar may be used.

[0008] containing water vapor, carbon dioxide or oxygen
Gas is, for example, H_TwoO, CO _Two, O_TwoGas, there is
Or a gas that does not react with these gases_TwoO, CO_Two,
O_TwoIt refers to gas diluted gas. As a dilution gas
Is, for example, N_TwoAlternatively, Ar may be used.

When O ₂ is used as the above gas, magnesia MgO solid can be precipitated by reaction with magnesium chloride gas. The reaction is shown below.

MgCl ₂ + 1 / 2O ₂ → MgO + Cl ₂

Similarly, when H ₂ O is used, magnesia MgO solid can be precipitated by reaction with magnesium chloride gas. The reaction is shown below.

MgCl ₂ + H ₂ O → MgO + 2HCl

When a mixed gas of CO ₂ and H ₂ is used as the above gas, magnesia solids can be precipitated by reaction with magnesium chloride. The reaction is shown below.

MgCl ₂ + CO ₂ + H ₂ O → MgO + CO + 2HCl

By the reaction between magnesium vapor and steam,
A solid of magnesia MgO can be deposited. The reaction is shown below.

Mg + H ₂ O → MgO + H ₂

When CO ₂ is used, magnesia solids can be precipitated by reaction with magnesium vapor. The reaction is shown below.

Mg + CO ₂ → MgO + CO

The temperature of 700 ° C. or more is desirable for the combination of Mg vapor and O ₂ , H ₂ O, and CO ₂ . This is because if the temperature is lower than 700 ° C., part of the Mg vapor tends to be condensed at the stage of transfer to the reaction site, so that Mg cannot be effectively used for the intended reaction.

The Mg vapor may be generated by heating molten Mg. In this case, the heating temperature is 700 to 1200
It is desirable to be in the range of ° C. This is because Mg below 700 ° C
This is because the rate of generation of steam is too low.
If the temperature exceeds ℃, the generation of Mg vapor becomes intense, and it becomes difficult to control the flow rate and pressure of a gas containing the same.

Mg as a starting material may be ingot or powder. When Mg is powder, Mg
-A mixed powder of CaO and Mg-Al may be used. Mg
Since powder easily ignites, mixed powder is preferable.

The Mg vapor may be generated by reacting MgO and Al as follows. 3MgO + 2Al → 3Mg + Al ₂ O _{3 In} this case, the reaction temperature is preferably in the range of 850 to 1700 ° C. This is because if the temperature is lower than 850 ° C., the reaction rate is too slow. On the other hand, if the temperature exceeds 1700 ° C., the generation of Mg vapor becomes intense, and it becomes difficult to control the flow rate and pressure of the gas containing the same.

The concentration of Mg vapor or magnesium chloride contained in the gas (diluent gas) containing Mg vapor or magnesium chloride is 0.1 vol. % Is desirable. This corresponds to 0.1 vol. If the amount is less than 10%, the reaction rate is too slow.

Reactive gas (O ₂ , H ₂ O, CO ₂ gas)
The concentration of the reactive gas contained in the gas (diluent gas) containing 1 vol. % Is desirable. This corresponds to 1 vol. If the amount is less than 10%, the reaction rate is too slow.

As a gas containing a reactive gas, O ₂ ,
When two or more gases are contained from H ₂ O and CO ₂ , pure gases may be mixed, but various combustion gases may be used. Natural gas,
Any gas obtained by burning liquefied petroleum gas, kerosene, heavy oil, coal, coke oven gas, blast furnace gas, converter gas, or the like with air or oxygen can be used. Further, exhaust gases from various heating furnaces may be used as needed.

Next, the reaction on the surface and the surface layer of the brick will be described. The magnesium chloride (containing) gas that has also penetrated into the pores of the brick reacts with the aforementioned reactive gas. This reaction is catalyzed on the solid surface and proceeds preferentially on the brick surface. If this reaction continues, the gas containing magnesium chloride is consumed, so that the reactive gas gradually enters the pores and the like. In this manner, magnesia is deposited inside the pores while the reaction interface of the two types of gas proceeds deep inside the pores and the like, and the pores are filled.

The reaction between the gas containing magnesium chloride and the reactive gas continues on the surface of the alumina-magnesia castable, and the solid (alumina) continues to be deposited on the surface of the alumina-magnesia castable. In this way, a layer of precipitate is formed on the surface of the castable. The pores on the surface of the alumina-magnesia castable are protected by this layer of precipitate.

In the present invention, the refractory (alumina
By depositing alumina, which is one of the compositions of magnesia castable, the reinforcing body and the refractory are integrated, and the problem of falling off from the reinforcing part can be solved.

[0029]

FIG. 1 is a sectional view schematically showing one example of an embodiment of the present invention. In the figure, 1 is a ladle, 2
Denotes a ladle nozzle, 5 denotes an iron shell, 7 denotes a refractory, 10 denotes a sealing lid, and 20 denotes a gas inlet tube.

First, heating is performed to remove moisture contained in the refractory after molding. Heating the refractory is also desirable from the viewpoint of accelerating the reaction of gas on the surface of the refractory, that is, the precipitation of magnesia. Next, the sealing lid 1 shown in FIG.
0 is placed on the opening. The portion of the ladle nozzle 2 is separately closed with a refractory or the like.

In this state, the gas containing magnesium chloride is introduced into the ladle 1 as it is or after preheating. The introduction method is as follows.
0 is installed, and it is easy to introduce the gas from the gas introduction pipe 20. In this case, it goes without saying that a switching valve or the like is provided between the gas containing magnesium chloride and the reactive gas.

The gas containing magnesium chloride is ladle 1.
After filling the inside, a reactive gas such as steam is introduced.
In this case, pressurization is initially required to introduce a reactive gas such as water vapor, but both gases are consumed as the gas reaction (precipitation of magnesia) proceeds on the surface of the refractory 7. You. Therefore, after the start of the reaction, the reactive gas can be introduced without particularly applying pressure. It is desirable that the reactive gas be preheated as much as possible from the viewpoint of securing the reaction temperature.

Conversely, the reactive gas may be introduced into the ladle 1 first, and then the gas containing magnesium chloride may be introduced into the ladle 1. Thus, 2
By reacting the two gases, a magnesia layer is formed on the surface of the alumina-magnesia refractory. When it is desired to increase the thickness of the magnesia layer on the surface of the refractory, this operation can be repeated a plurality of times to achieve the object.

[0034]

According to the present invention, by reacting magnesium vapor or magnesium chloride gas or the like with water vapor or the like, magnesia is deposited in the pores of the alumina / magnesia castable, whereby the refractory on the working surface side is strengthened. The life of the refractory lining can be extended.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ladle 2 Nozzle 5 Iron shell 7 Refractory 10 Sealing lid 20 Gas introduction pipe

Claims (1)

[Claims] 1. With the ladle opening closed, first
A gas containing magnesium vapor or magnesium chloride, or a gas containing water vapor, carbon dioxide or oxygen is supplied into the ladle to fill the ladle, and then the other gas is supplied. A method for extending the life of a refractory lining with a ladle, wherein the refractory is supplied into the ladle.