JPH11199316A - Refractory for furnace wall, method of using the same, and melting furnace - Google Patents

Abstract

(57) [Problem] To provide a refractory for a furnace wall having corrosion resistance equal to or higher than that to which chromium oxide is added without adding chromium oxide. A refractory for a furnace wall containing aluminum oxide (Al ₂ O ₃ ) as a main component, comprising spinel (MgAl ₂ O ₄ ).
The content of content 10 to 45% by weight and zirconium oxide (ZrO ₂₎ is that the range of 10 to 35 wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory used for a furnace wall of a melting furnace for melting incineration ash, industrial waste, and the like, a method of using the same, and a melting furnace using the refractory. .

[0002]

2. Description of the Related Art Conventionally, as a constituent material of a furnace wall in a melting furnace for melting refuse incineration ash and industrial waste to reduce the volume, that is, as a refractory for the furnace wall, aluminum oxide (Al ₂ O _{3) is used.} ) as a main component, chromium oxide to exhibit corrosion resistance (Cr ₂ O ₃₎ is those compositions which are contained in an amount of 5 to 20% by weight is used.

[0003]

The above-mentioned conventional refractories are:
Since chromium oxide is contained, there is a fear that hexavalent chromium may be generated, and regarding the disposal of this refractory,
It is at present that we are struggling.

Accordingly, an object of the present invention is to provide a refractory for a furnace wall having a corrosion resistance equal to or higher than that of a conventional one containing chromium oxide without using chromium oxide, a method of using the same, and a melting furnace. Aim.

[0005]

In order to solve the above-mentioned problems, a refractory for a furnace wall according to the present invention comprises aluminum oxide (Al).
₂ O ₃ ) is a refractory for a furnace wall mainly composed of 10 to 45% by weight of spinel (MgAl ₂ O ₄ ) and 10 to 35% by weight of zirconium oxide (ZrO ₂ ). The range is as follows.

According to the above refractory, corrosion resistance equal to or higher than that of a refractory containing chromium oxide can be obtained without containing chromium oxide. Further, the method of using the refractory for a furnace wall of the present invention is a method of using the refractory for an inner wall surface of a furnace body in which the basicity of an object to be treated is in a range of 0.5 to 2, and the corrosion resistance on the inner wall surface is reduced. It can be surely demonstrated.

Further, in the melting furnace of the present invention, the refractory for a furnace wall is disposed on an inner wall surface of a furnace main body for melting a material to be melted, thereby providing a melting furnace excellent in corrosion resistance. I can do it.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a refractory for a furnace wall according to an embodiment of the present invention will be described. The refractory for a furnace wall according to the present embodiment is obtained by adding spinel (MgAl ₂ O ₄ ) to a refractory mainly containing aluminum oxide (Al ₂ O ₃ ).
45% by weight and 10% zirconium oxide (ZrO ₂ )
To 35% by weight, respectively.
The preferred content is in the range of 10 to 40% by weight of spinel and 10 to 30% by weight of zirconium oxide, and the basicity of a usable (possible corrosion resistance) usable melt (workpiece) is It is in the range of 0.5 to 2.

The results of erosion tests for investigating the corrosion resistance of refractories made variously with compositions in the above range and refractories variously made with compositions outside the above range are shown in Table 1 below. ] And [Table 2].

First, a method of preparing a refractory used in the erosion test, that is, a sample, and a test method thereof will be described. A mixture of aluminum oxide, spinel, zirconium oxide, and chromium oxide each having an average particle size of 50 μm at a ratio shown in Table 1 was mixed with water by a ball mill for 24 hours. C. for 24 hours. In addition, when mixing with a ball mill, PVA (polyvinyl alcohol) was added as a binder at a ratio of 3 with respect to a powder weight of 100.

[0011] 300 kg of the powder obtained by this drying
/ Cm ² , and then sintering at 1600 ° C. for 2 hours in the air.
A rectangular test piece of 0 mm × 70 mm × 65 mm, that is, a sample was obtained.

Next, as an experimental method, a hole having a diameter of 30 mm and a depth of 35 mm was formed in the center of each of the above-mentioned samples (test pieces), and this hole was formed as shown in Table 2 below. Three kinds of erosion agents whose basicity was adjusted to 0.5, 1.0 and 2.0 were put in the atmosphere at 1400 ° C. for 100 hours.
Heated and held for hours. In addition, the basicity of the erosion agent is 0.5 to
The range of 2.0 is usually used when the basicity of the incinerated ash is 0.1.
7 to 1.0.

After heating and holding, the central portion of the sample was cut, and the impairment amount and the permeation amount were measured according to JIS R2214. The evaluation in Table 1 is a relative evaluation of each sample, with the value for the Al ₂ O ₃ -5% Cr ₂ O ₃ material being 1. This evaluation is ○
And x, the result was evaluated as ○ when the value was equal to or superior to the value of the Al ₂ O ₃ -Cr ₂ O ₃ material, and as x when inferior.

[0014]

[Table 1]

[0015]

[Table 2]

Judging based on the evaluation in Table 1, when the content of spinel is in the range of 10 to 40% by weight and the content of zirconium oxide is in the range of 10 to 20% by weight (sample Nos. 6, 7, 8, 13, 14, 17 and 18)
It can be seen that good results were obtained for each. On the other hand, when the content of spinel is 50% by weight (sample No. 10), the content of zirconium oxide is 10%.
When it was in the range of 20% by weight (Sample No. 9), the evaluation was poor. That is, as shown in Sample No. 10, when the spinel content is 50% by weight or more, magnesium oxide (MgO) generated by decomposition of the spinel causes a slaking reaction [MgO + H ₂ O → Mg (OH) ₂ ] to generate cracks. I do. Further, as shown in Sample No. 9, when the content of zirconium oxide is 40% by weight or more, thermal spalling property is reduced and cracks occur. further,
The evaluation was also poor when only spinel was added (Sample No. 4) and when only zirconium oxide was added (Sample No. 5). As a comparative example, the results obtained when only chromium oxide was added were sample numbers 1, 2, 3, and 1.
1, 12, 15 and 16.

Taking these results into consideration, the appropriate proportions of spinel and zirconium oxide to be added (contained) to aluminum oxide are 10 to 45% by weight and 10 to 45% by weight.
-35% by weight.

As a furnace suitable for incorporating the refractory, there is a melting furnace for melting incineration ash, industrial waste and the like to reduce the volume, and is disposed on the inner wall surface of the furnace body. . Of course, in this case, corrosion resistance on the inner wall surface is exhibited.
In addition, it can be applied to the inner wall surface of the furnace main body of the incinerator.

Here, the result of incorporating the refractory according to the present invention into an actual melting furnace will be described. [Table 1]
400 mm × 40
A block of 0 mm x 200 mm was manufactured, and the basicity was 0.
5 was incorporated into an industrial waste melting furnace and operated continuously for 200 hours.

Then, the block was taken out and compared with a conventionally incorporated refractory mainly composed of aluminum oxide containing 5% by weight of chromium oxide. As a result, while the conventional refractory lost 15 mm, the refractory according to the present invention lost 13 mm, and it was confirmed that the refractory was superior to the conventional refractory in corrosion resistance.

As described above, the refractory according to the present invention does not contain chromium oxide and has corrosion resistance equal to or higher than that of a conventional refractory containing chromium oxide. Hexavalent chromium is not generated, and there is no problem in disposal of refractories.

When the refractory according to the present invention is used as a furnace wall of a melting furnace, the basicity of the material to be melted is 0.5%.
When it is in the range of 2.0 to 2.0, corrosion resistance can be reliably obtained.

[0023]

As described above, according to the refractory of the present invention,
Without containing chromium oxide, corrosion resistance equal to or higher than that of conventional refractories containing chromium oxide can be exerted. There is no problem with disposal. Further, according to the method for using the refractory of the present invention and the melting furnace, corrosion resistance can be reliably exhibited.

Claims (3)

[Claims] 1. A furnace wall refractory containing aluminum oxide (Al ₂ O ₃ ) as a main component, comprising spinel (MgAl ₂ O ₄ ).
Furnace wall refractories, wherein the amount is in the range of 10 to 35 wt% of the content of 10 to 45% by weight and zirconium oxide (ZrO ₂₎ of. 2. A method for using a refractory for a furnace wall according to claim 1, wherein the refractory for a furnace wall is used on an inner wall surface of a furnace main body in which the basicity of an object to be treated is in a range of 0.5 to 2. How to use refractories for furnace walls. 3. A melting furnace wherein the refractory for a furnace wall according to claim 1 is arranged on an inner wall surface of a furnace body for melting a material to be melted.