JP3401604B2 - ZrO2-based refractory cast refractory for melting tank and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to municipal waste incineration ash which is general waste, fly ash (dust ash) as special waste, incineration ash of infectious waste, sewage sludge cake and industrial waste. coal ash and slag or the like in large quantities discharged from the steel industry or the like (hereinafter referred to as waste) melting tank for ZrO ₂ based fused cast refractories suitable for use in melting the ones with many CaO components and is The present invention relates to a manufacturing method.

[0002]

2. Description of the Related Art The problem of treating municipal solid waste has become more and more important in recent years, and direct landfilling has become increasingly difficult. Therefore, it has come to be incinerated and landfilled with the volume reduced, but recently, due to the convenience of the landfill site, incineration ash has been melted to further reduce the volume. . However, incineration ash and its fly ash wastes, etc. should be treated with C in order to assist combustion and lower the melting temperature or to treat with HCl.
In many cases, aO is added, and coal ash and slag in the steel industry contain a large amount of CaO, and when these are melt-processed, the reactivity of CaO in the melt is high. There is a problem that the refractory used in the melting furnace is easily corroded by CaO, which shortens the life of the furnace.

[0003]

DISCLOSURE OF THE INVENTION The present invention is intended for melting a large amount of CaO components such as incinerated ash of municipal waste which is a general waste, fly ash as special waste or waste such as coal ash. Zr that is not easily corroded by the melt
It is intended to extend the life of a melting furnace by using an O ₂ type melt cast refractory as a melting tank.
However, although the ZrO ₂ -based molten cast refractory has extremely good corrosion resistance, it does not always have satisfactory spall resistance. Therefore, even when it is necessary to temporarily stop the operation of the melting furnace, the furnace temperature is kept at room temperature. There were many inconveniences, such as having to operate continuously without lowering it.

[0004]

MEANS FOR SOLVING THE PROBLEMS ZrO for a melting tank of the present invention
₂ based fused cast refractories, in order to improve the spalling resistance which is a defect of a high ZrO ₂ based fused cast refractories, high ZrO ₂
A block of substantially the same material as this is cast in advance at the time of casting of the system melt cast refractory, and the block is surrounded by the high ZrO ₂ system melt cast refractory.

[0005]

That is, instead of casting the ZrO ₂ system melt-casting refractory for the melting tank as a homogeneous and integral one at the time of casting, the same material as the high ZrO ₂ system melt-casting refractory is used. advance high lumps of ZrO ₂ based fused cast refractories or pulverized was allowed to block molded with a binder such as water glass, to be a high ZrO ₂ based refractory composition to the surrounding as if the core of the block The melted material is poured into a cast stuffed body, which is used as a ZrO ₂ type melt cast refractory material for a melting tank.

[0006] When a high ZrO ₂ based fused cast refractories used for lining material of the melting furnace waste such as waste incineration ash or its fly ash, when stopping the operation at night, high when the furnace temperature was reduced Zr
There is a high possibility that abnormal expansion peculiar to O ₂ -based refractory will occur and lead to destruction of the refractory, so the furnace temperature had to be controlled so as not to fall below a certain range. Even in such a case, the spalling cannot be endured due to the stress caused by the reheating. In order to melt wastes such as incinerated ash of municipal solid waste and its fly ash, it is extremely difficult to operate the furnace under constant and stable conditions because the amount and composition thereof are constantly changing, and high ZrO ₂ system melting As for the cast refractory, although the melt having a large amount of CaO component is a very good material for the corrosion resistance, the spalling resistance is often unsatisfactory for the reasons described above.

[0007] Therefore, the present inventors have conducted a study on a method for imparting spalling resistance to a ZrO ₂ system melt casting refractory for a melting tank in order to improve this point, and as a result, have found that a high ZrO ₂ system melt casting is performed. Inside the refractory, a molded block with similar chemical and physical properties and with thermal insulation is embedded as if it were a core, and the block improves thermal insulation to improve at least the corrosion resistance of the outer surface. It is intended to improve the spalling resistance without lowering it.

FIG. 1 is a perspective view showing a structure in which a part of a ZrO ₂ type melt cast refractory for a melting tank is cut away according to an embodiment of the present invention. Inside the high- ZrO ₂ system melt cast refractory 2, a heat-insulating molding block 1 having similar chemical and physical characteristics is formed by being cast and loaded like a core.

That is, by covering the outer periphery with the high- ZrO ₂ type melt-casting refractory ₂ so that the molding block 1 (core) of substantially the same quality is present, heat insulation from the integrated high- ZrO ₂ type melt-casting refractory is performed. Property is improved and cracks are less likely to occur, and even if cracks occur in the outer layer of the high- ZrO ₂ -based molten cast refractory material 2, the same corrosion resistance and thermal expansion properties are achieved in the center. Since the molding block 1 (core) that it has is packed and loaded, the ZrO ₂ type melt casting refractory for the melting tank does not come off.

As described above, the molded block to be cast is formed into a block by molding a lump or crushed material of the same material as the high- ZrO ₂ type molten cast refractory forming the outer peripheral portion with a binder such as water glass. the thing is not preferable.

[0011]

Example 1 ZrO ₂ 93%, Al ₂ O ₃ 0.6%, Si
A crushed material of a high ZrO ₂ system melt cast refractory containing 14.0% O ₂ was crushed to 100 μ or less, and 95 parts of this powder was mixed with water glass 5
Parts were added to form a prism of 140 × 40 × 340. This block is placed as a core in a mold, and a high Zr of the same composition as that of the core is formed around the block so that the thickness becomes 30 mm.
A melt of O ₂ based refractory formulation was injected. As a result, 20
A 0 × 100 × 400 prismatic ZrO ₂ system melt cast refractory for a melting tank was obtained.

[0012]

Example 2 ZrO ₂ 40%, Al ₂ O ₃ 45.9%, S
iO Al ₂ O ₃ -SiO containing ₂ 13.0% ₂ - crushed 10 parts of the ZrO ₂ fused cast refractories were mixed with the parts of ZrO ₂ powder 87 and aluminum phosphate 3 parts, Al ₂ O ₃ -SiO ₂
- around the crushed ZrO ₂ based fused cast refractories was obtained lumps as covered with ZrO ₂ powder. This block was placed as a core in a mold, and a melt of a high ZrO ₂ -based refractory formulation having almost the same components as the core was poured around the block. As a result, a 200 × 100 × 400 prismatic ZrO ₂ system melt cast refractory for a melting tank was obtained.

The ZrO ₂ type melt-cast refractory for melting tanks obtained in Examples 1 and 2 was heated 25 times from 800 ° C. to 1200 ° C., and then cooled to 800 ° C. again 25 times. No cracks were observed in the ZrO ₂ system melt-casting refractory for a melting tank. Further, when used as the lining of the incinerator ash melting furnace, no cracks were generated in any of the ZrO ₂ -based molten cast refractories for the melting tank, unlike the conventional high ZrO ₂ -based molten cast refractories.

As a reference example, an integrated high- ZrO ₂ type melt-cast refractory having the same components as those of Examples 1 and 2 but not using a core was produced, and the crack generation conditions were compared under the same conditions. The high- ZrO ₂ system melt-cast refractory having the same composition as that of No. 1 cracked at 5 times, and had the same composition as that of Example 2.
In the high- ZrO ₂ system melt cast refractory, cracks occurred after 7 times.

[0015]

The ZrO ₂ type melt cast refractory for a melting tank and the method for producing the same according to the present invention have the following effects because they are configured as described above. That is, the ZrO ₂ type melt cast refractory for a melting tank according to the present invention has no problem in its corrosion resistance since the outer layer is the same as the conventional one, and the spalling resistance is improved by the heat insulation due to the internal molding block. because there, are I Do not easily broken such that as in the conventional high ZrO ₂ based fused cast refractories
Temporarily, the outer layer of the high-ZrO ₂ system melt-cast refractory is cracked.
Even if a rack enters, the inner layer has the same level of corrosion resistance as the outer layer.
Because the molding block with thermal expansion is surrounded by casting,
ZrO ₂ type melt casting refractory for melting tank will fall apart
No peeling occurred and its reliability increased significantly.

[Brief description of drawings]

FIG. 1 is a Z for a melting tank according to an embodiment of the present invention.
It is a perspective view showing a partially cutaway structure of and rO ₂ based fused cast refractories.

[Explanation of symbols]

1 Molded block (core) 2 Highly cast ZrO ₂ melt-cast refractory

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-42466 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 41/87 C04B 35 / 48,35 / 60,35 / 62 B22D 19/00

Claims (2)

(57) [Claims] 1. A block of high mass of the ZrO ₂ fused cast refractories and pulverized product was molded with a binder such as water glass, Guru rare, the furnace inner side cast by high ZrO ₂ based fused cast refractories It has excellent spall resistance, which is characterized by the formation of an outer layer on its surface, and it contains many CaO components such as incinerated ash and its fly ash.
ZrO ₂ type fused cast refractory for melting tanks that melts waste materials. _2. A block of a high ZrO ₂ system melt cast refractory lump or crushed product is molded using a binder such as water glass, and the block is encapsulated when the high ZrO ₂ system melt cast refractory is cast. It has excellent spall resistance, which is characterized by forming an outer layer on the surface that will be the inner surface of the furnace by casting as described above.
Melts waste materials with high CaO content, such as ash and fly ash.
A method for producing a ZrO ₂ -based molten cast refractory for a melting tank.