JP2004315309A - Firebrick and furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a firebrick that is sufficiently protective from materials in a furnace such as a corrosive gas or ash, and to provide a furnace using the same. <P>SOLUTION: The firebrick 10 has a rectangular parallelepiped with faces 1-6 of from the first to the sixth face. The protective layer 7 is formed on not only the first face which is faced with the face exposed in the furnace but also on the first face 1 side among the faces 2-5 of from the second to the fifth face. The thickness of the protective layer 7 in the face 2-5 is in the range of 100-1,000 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a firebrick and a furnace, and more particularly to a firebrick having a protective layer and a furnace lined with the firebrick.
[0002]
[Prior art]
It is well known to form a protective layer on a furnace-facing surface of a refractory brick. For example, Japanese Patent Application Laid-Open No. 8-119775 describes that a protective layer having a high silica purity is formed by forming a surface layer of sodium borosilicate and then evaporating sodium by increasing the temperature.
[0003]
JP-A-10-265281 describes a magnesia-spinel brick having a silica-based protective layer formed using colloidal silica.
[0004]
JP-A-10-259080 describes a firebrick having a coating layer formed with an alkali phosphate.
[0005]
JP-A-10-330758 describes a refractory brick having a surface coating formed of lithium sodium borosilicate.
[0006]
Japanese Patent Application Laid-Open No. 2000-319659 describes a firebrick having a coating layer of sodium borosilicate containing BaO and SrO. The same publication states that Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , Zr, SiO _{4 and the} like may be added to the coating layer.
[0007]
JP-A-5-154627 describes a firebrick having a surface layer made of zirconia, calcia, magnesia, graphite, or the like.
[0008]
JP-A-5-306181 describes that a carbon layer is provided on the surface of a refractory brick.
[0009]
[Patent Document 1]
JP-A-8-119775 [Patent Document 2]
JP-A-10-265281 [Patent Document 3]
JP 10-259080 A [Patent Document 4]
JP-A-10-330758 [Patent Document 5]
Japanese Patent Application Laid-Open No. 2000-319659 [Patent Document 6]
JP-A-5-154627 [Patent Document 7]
JP-A-5-306181
[Problems to be solved by the invention]
The present invention relates to a firebrick having a protective layer capable of protecting not only a first surface exposed in a furnace of a firebrick but also a surface near the first surface, and a furnace provided with the firebrick. And to provide.
[0011]
[Means for Solving the Problems]
The refractory brick of the present invention is a refractory brick used as a furnace material, and has a first surface exposed in the furnace and at least a first surface side of all surfaces adjacent to the first surface. And a protective layer formed on each of the portions.
[0012]
In the refractory brick and the furnace according to the present invention, not only the first surface of the refractory brick but also all the areas adjacent to the first surface in the furnace near the refractory brick have corrosive gas or ash content. Etc. from the furnace material.
[0013]
That is, when the protective layer has the refractory corrosion preventing property, the erosion of the surface layer of the refractory by a corrosive gas such as a chlorine gas, a sulfur oxide gas, and a gas containing various alkali components is prevented. Further, when the protective layer is a dense ceramic film, the wear resistance of the refractory for furnace material is enhanced.
[0014]
When the protective layer has the property of preventing the in-furnace substance such as ash from adhering, the in-furnace substance such as ash hardly adheres to the surface of the refractory brick, and even if it adheres, the substance easily comes off naturally.
[0015]
In the present invention, the protective layer may be such that the lower layer has corrosion prevention properties and the upper layer has adhesion prevention properties such as ash.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments will be described with reference to the drawings.
[0017]
FIG. 1 is a perspective view of the refractory brick according to the embodiment. The refractory brick 10 has a rectangular parallelepiped shape, a first surface 1 exposed in the furnace, second, third, fourth and fifth surfaces 2 to 5 adjacent to the first surface, and 1 and a sixth surface 6 on the opposite side.
[0018]
A protective layer 7 is formed on the entire first surface 1. The protective layer 7 is also formed on the side closer to the first surface 1 among the second to fifth surfaces 2 to 5.
[0019]
In addition, the range in which the protective layer 7 is provided on the second to fifth surfaces 2 to 5 is preferably about 5 to 100 mm, particularly about 10 to 70 mm from the edge of the first surface 1. If this range is excessively small, the protection of the second to fifth surfaces 2 to 5 may be insufficient. If this range is too large, the cost increases.
[0020]
In the second to fifth surfaces 2 to 5, the thickness of the protective layer 7 is preferably 100 to 1000 μm, particularly preferably about 200 to 800 μm. If the thickness is excessively small, the protection is insufficient, and if the thickness is excessively large, there is a possibility that the brickwork is hindered. Further, if the protective layer is excessively thick, the cost may increase, and depending on the material, peeling may easily occur due to a difference in thermal expansion with the refractory brick.
[0021]
The thickness of the protective layer provided on the first surface 1 may be greater. However, when the thickness is excessively large, the film is easily peeled off.
[0022]
The refractory brick 10 is lined with a furnace so that the first surface 1 faces the inside of the furnace.
[0023]
By forming the protective layer 7 in this manner, corrosion damage of the refractory brick is prevented by contact with the corrosive gas in the furnace. When the protective layer 7 has such a property that the in-furnace material such as ash does not easily adhere, the ash is prevented from adhering, and the refractory brick is prevented from being damaged by the attached ash.
[0024]
When the protective layer 7 has a laminated structure of a lower layer having corrosion prevention properties and an upper layer having adhesion prevention properties such as ash, refractory brick protection properties are remarkably good.
[0025]
At the interface between the firebrick base material and the protective layer 7, a transition layer containing both components may be formed. In the normal case, the components of the protective layer 7 become richer in the transition layer as it approaches the protective layer 7 side.
[0026]
Even when the protective layer 7 has a laminated structure of a corrosion prevention layer and an adhesion prevention layer such as ash, a transition layer may be formed at the interface between both layers.
[0027]
In the present invention, the base material of the refractory brick includes alumina-based refractories, magnesia-based refractories (including magcro- and magcarbon-based), silica-based refractories (clay-based refractories), and alumina-based refractories. Inexpensive chamotte bricks having a fire resistance (SK) of 32 to 37 are often used, but are not limited thereto.
[0028]
The protective layer 7 is preferably inexpensive inorganic oxide-based ceramics when to include a corrosion resistance to the protective layer _{7, SiO 2, ZrSiO 4,} 2SiO 2 · 3Al 2 O 3 _{Specifically, ZrO} 2, Cr ₂ O ₃ , TiO ₂ , MgO, MgAl ₂ O ₄ , B ₂ O ₃ or the like can be employed.
[0029]
The apparent porosity of the protective layer 7 having corrosion resistance is 10% or less, preferably 5% or less. If it exceeds 10%, there is a disadvantage that erosion of corrosive gas cannot be effectively prevented.
[0030]
In the case where the protective layer 7 is provided with an adhesion preventing property such as ash, carbide-based ceramics, nitride-based ceramics, boride-based ceramics, carbon, and the like are preferable. As the carbide-based ceramic, for example, one or more of inexpensive SiC, ZrC, TiC, B ₄ C, W ₂ C, WC, and the like can be used. In addition, as the nitride-based ceramic, one or more of Si ₃ N ₄ , TiN, BN, ZrN, and the like can be used. As the boride-based ceramic, one or more of B ₄ C, BN, TiB ₂ , CrB ₂ , ZrB ₂ , and SiB ₂ can be used. Coke, graphite and the like can be used as carbon.
[0031]
In order to form the protective layer, it is preferable that a powdery, liquid or slurry material for forming the protective layer is attached to the refractory brick, and then integrated with the refractory brick in a firing step of the refractory brick.
[0032]
For example, in the refractory brick press-forming step, a layer of the powder material for the protective layer may be formed on the surface of the refractory brick substrate, and this layer may be sintered and integrated with the refractory brick substrate.
[0033]
Further, after molding, a liquid or slurry-like material may be applied by spraying, shading, dipping or the like, dried if necessary, and then the protective layer 7 may be integrated with the refractory brick substrate in a firing step.
[0034]
The protective layer forming material may be formed into a film, and this film may be adhered to the surface of the fire-resistant brick molded product, and then the protective layer 7 may be integrated with the fire-resistant brick substrate in a firing step.
[0035]
In order to firmly integrate the protective layer and the firebrick base material in the firing step, a sintering accelerator may be contained in the material for forming the protective layer.
[0036]
Examples of the sintering accelerator include Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ —ZrO ₂ based sintering accelerator and Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ based sintering accelerator. Can be adopted. In addition, many low-melting glass, fine powder glass and the like may be used. Of course, other than these may be used.
[0037]
The addition amount of the sintering accelerator is 10% by weight or less, preferably 2% by weight or less. If the content exceeds 10% by weight, the strength of the corrosion-resistant film itself against high heat will be deteriorated, and the life will be shortened.
[0038]
When the protective layer is at least one of a carbide-based ceramic, a nitride-based ceramic, a boride-based ceramic, and carbon, an antioxidant may be added to the protective layer.
[0039]
As the antioxidant, for _example, it can be employed as Al ₂ O ₃ -SiO ₂ -TiO ₂ system of antioxidants. In addition, zirconia-based glass and glass containing boride may be used. Of course, other things may be used.
[0040]
The addition amount of the antioxidant is 10% by weight or less, preferably 5% by weight or less. If the content exceeds 10% by weight, clinker may easily adhere to the protective layer.
[0041]
In addition, the shape of the refractory brick of the embodiment of the present invention is a rectangular parallelepiped, but is not limited to this. The first surface facing the inside of the furnace may have a curved surface, or all the surfaces adjacent to the first surface may be curved. May be four or less or more.
[0042]
Examples of the furnace to which the refractory brick of the present invention is applied include various industrial furnaces such as a refuse incinerator, a cement firing furnace, other furnaces, an annealing furnace, a heating furnace, and a steelmaking furnace. Examples of the steelmaking furnace include a blast furnace, a converter, an electric furnace, a tapping gutter, a ladle, a tundish, an RH (vacuum degassing device for steelmaking), and a DH. The furnace is not limited to these. Further, the refractory of the present invention is applied not only to the furnace body but also to its peripheral equipment.
[0043]
The refractory brick of the present invention can be applied not only when a new furnace is installed, but also when an existing furnace is replaced with an existing refractory brick when renewing the refractory brick.
[0044]
Examples of in-furnace substances such as ash that may adhere to refractory bricks include various types of refuse incinerated in refuse incinerators or their incinerated ash, and various cement raw materials such as limestone, clay, silica sand, etc. In the clinker and steelmaking furnaces, various raw materials such as iron ore, coke, limestone and manganese ore, slag, molten steel and the like are exemplified.
[0045]
【The invention's effect】
As described above, according to the present invention, it is possible to sufficiently protect refractory bricks from furnace materials such as corrosive gas and ash.
[Brief description of the drawings]
FIG. 1 is a perspective view of a refractory brick according to an embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st surface 2 2nd surface 3 3rd surface 4 4th surface 5 5th surface 6 6th surface 7 Protective layer 10 Firebrick

Claims (11)

A refractory brick used as a furnace material, wherein a protective layer is formed on a first surface exposed in the furnace and at least a portion on a first surface side of all surfaces adjacent to the first surface. A firebrick characterized by being made. The firebrick according to claim 1, wherein the thickness of the protective layer formed on all surfaces adjacent to the first surface is 100 to 1000 µm. 3. The protective layer according to claim 1, wherein the protective layer is formed in a range of 5 to 100 mm from an edge of the first surface among all surfaces adjacent to the first surface. 4. Refractory brick. The refractory brick according to any one of claims 1 to 3, wherein the protective layer is formed by being integrated with the refractory brick in a firing step of the refractory brick. 5. The protective layer according to claim 1, wherein the protective layer is at least one selected from the group consisting of inorganic oxide-based ceramics, carbide-based ceramics, nitride-based ceramics, boride-based ceramics, and carbon. A firebrick, characterized in that: The refractory brick according to any one of claims 1 to 5, wherein the protective layer has corrosion prevention properties for preventing erosion of the refractory brick by corrosive gas in the furnace. The refractory brick according to any one of claims 1 to 5, wherein the protective layer has a property of preventing in-furnace substances such as ash from adhering to the furnace. The protective layer according to any one of claims 1 to 4, wherein the protective layer has a corrosion preventing property for preventing erosion of the refractory brick by corrosive gas in the furnace, and a property for preventing adhesion of substances in the furnace such as ash. Refractory bricks, characterized by having an upper layer having: The firebrick according to claim 6 or 8, wherein the layer having corrosion prevention properties is mainly composed of an inorganic oxide-based ceramic. 9. The method according to claim 7, wherein the layer having anti-adhesion properties is mainly composed of at least one selected from the group consisting of carbide ceramics, nitride ceramics, boride ceramics, and carbon. And refractory bricks. 11. A furnace lined with refractory bricks, wherein at least a part of the refractory bricks is the refractory brick according to any one of claims 1 to 10.

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