JP2001328861A - Cr-CONTAINING REFRACTORY AND FURNACE USING THE SAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a refractory capable of having high corrosion resistance, scarcely causing cracking and excellent in durability. SOLUTION: This Cr-containing refractory consists essentially of A12O3 and comprises Cr2O3 in an amount of 10-40% expressed in terms of weight ratio and a softener capable of softening at >=1,000 deg.C in an amount of 5-10% expressed in terms of weight ratio. The softener is preferably soda-lime glass. An oxide, a nitride, a carbide or a boride of Al, Mg, Zr and/or Si, e.g. spinel, zircon, mullite or forsterite can further be contained in the Cr-containing refractory.

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 refuse incinerator, ash melting furnace, melting kiln, cement firing furnace, gasification melting furnace and the like.

[0002]

2. Description of the Related Art In recent years, due to an increase in waste, an effective treatment method has been sought. Melting of waste incineration ash by heating is considered to be advantageous in terms of volume reduction and harmlessness, and its introduction is progressing mainly in incinerators of local governments. In addition, in the field of cement production, recently, heat from waste incineration is used from the viewpoint of energy saving. Refractories containing Cr ₂ O ₃ are used for the furnace walls of these devices. However, incineration and melting of waste require a high temperature of 1400 ° C. or more, and the composition of the waste is not constant, so that refractories are severely damaged. So now C
A refractory having a composition containing 10% or more of r ₂ O ₃ by weight is used. However, the addition amount of Cr ₂ O ₃ is at most 40%, and it is known that the addition of more than this does not improve the corrosion resistance (earth, others, refractories,
49, 11, (1997)).

[0003]

As described above, it is known that increasing the amount of Cr ₂ O ₃ in a refractory improves the corrosion resistance of the refractory. However, there is a problem that cracks easily occur due to mechanical causes or the like. For this reason, although a high Cr ₂ O ₃ refractory is currently used, its durability is not sufficient.

[0004] In view of such circumstances, an object of the present invention is to provide a refractory which maintains high corrosion resistance, hardly causes cracks, and has excellent durability.

[0005]

The Cr-containing refractory according to the present invention comprises Al ₂ O ₃ as a main component, 10 to 40% by weight of Cr ₂ O _3, and a softening material which softens at 1000 ° C. or more. It contains 5 to 10% by ratio.

In the Cr-containing refractory of the present invention, the softening material is preferably soda-lime glass.

The Cr-containing refractory of the present invention further comprises Al,
Oxides, nitrides, carbides or borides of Mg, Zr and / or Si, for example spinel: MgAl ₂ O ₄
, Zircon: ZrSiO ₄ , mullite: 3Al ₂
O ₃ · 2SiO _2, forsterite: 2MgO ·
SiO ₂ may be contained.

A desired furnace is constructed by providing the refractory having the above structure on the inner surface of the furnace wall.

[0009]

EXAMPLES In Experiments 1 to 12, Cr ₂ O ₃ and soda lime glass as a softening material were added to each refractory. Table 1 shows the composition of the obtained Cr-containing refractory.

In experiments 13 to 21, Cr was added to each refractory.
₂ O ₃ , soda lime glass as a softener, and spinel, zircon, mullite or forsterite were added. Table 2 shows the composition of the obtained Cr-containing refractory.

The Cr-containing refractories obtained in Experiments 1 to 21 were evaluated for the following items.

A) Corrosion resistance test As shown in FIG. 1 and FIG.
A test piece (2) having a thickness of 30 mm was set inside a steel rotating cylinder (1) having a thickness of 2 mm. Na ₂ O 7%, Al ₂ O ₃ 8%, SiO ₂
33.5%, CaO 33.5%, Fe ₂ O ₃
A slag (3) having a composition of 18% is charged and a cylinder (1)
Was heated with a burner (5) while rotating on a roller (4) at 1500 ° C. for 50 hours. Specimen before and after test (2)
The erosion rate was calculated from the change in thickness of the sample, and the corrosion resistance was evaluated.

B) Crack evaluation test The fracture energy was measured by a three-point bending fracture test method shown in FIG. That is, the test piece (6) is placed on the support frame (7) at both ends, and a columnar load body (8) having an inverted triangular cross section is placed horizontally on the upper surface of the center of the length in the width direction of the test piece. Was loaded. The dimensions are a = 40 mm, d = 40 mm, b =
20 mm, l = 100 mm. The test specimen used was 40
× 40 × 150 mm. The evaluation is room temperature (RT) and 10
The comparison was performed at 00 ° C.

C) Heat-resistant spalling test A cycle of holding the test piece in a furnace at 1000 ° C. for 30 minutes and then rapidly cooling it in water was repeated 50 times, and the evaluation was made based on the change in elastic modulus before and after the test.

The results obtained in each test are summarized in Tables 1 and 2. Here, as a criterion for the evaluation, the corrosion resistance was 30% less than the erosion rate of the refractory material containing no softening material.
If it does not exceed%, it was regarded as good. In addition, the fracture energy is 10 times lower than that of a refractory material containing no softening material.
The higher the rate of increase at 00 ° C., the better. Further, regarding the change in elastic modulus, it was determined that the change was smaller than that of the refractory material not containing the softening material, and that all the samples were cleared, and the overall evaluation was ○ (good).

[0016]

[Table 1]

[0017]

[Table 2] In Table 2, spinel: MgAl ₂ O ₄ , zircon: Z
rSiO _{4, mullite:} 3Al ₂ O 3 · 2SiO
_2. Forsterite: 2MgO.SiO ₂

From these results, it was found that a predetermined amount of Cr ₂
By adding O ₃ and a predetermined amount of the softening material, corrosion resistance can be maintained and crack resistance can be improved. Here, the addition amount of the softening material is desirably 10% or less. If it exceeds 10%, no. As shown in FIG. 6, the erosion resistance decreases. In addition, No. 12 is a softening material, instead of soda-lime glass, mixed powder of the same composition (SiO ₂
73%, Al ₂ O ₃ 2%, CaO 7%, Na ₂
O 14%, MgO 4%), the same effect as the glass-added sample was obtained.

The remaining constituent components other than Cr ₂ O ₃ and the softening material may be compounds of Al, Mg, Zr, and Si. Similar effects can be obtained by using borides as well as oxides as in No. 11.

[0020]

According to the present invention, it is possible to provide a refractory which maintains high corrosion resistance, hardly causes cracks, and has excellent durability.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a corrosion resistance test apparatus.

FIG. 2 is a vertical sectional view showing a corrosion resistance test apparatus.

FIG. 3 (A) is a perspective view showing a method for measuring breaking energy. FIG. 3B is a diagram showing a fractured surface.

[Description of Signs] (1): Rotating cylinder (2) (6): Test piece (3): Slag (5): Burner (7): Support frame (8): Load body

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Rishi Ashida 1-7-89, Minami Kohoku, Suminoe-ku, Osaka F-term in Tachibai Shipbuilding Co., Ltd. 4G030 AA03 AA04 AA07 AA08 AA22 AA27 AA32 AA36 AA37 AA44 AA45 AA47 AA48 AA49 AA51 AA52 AA53 AA54 BA25 GA09 4K051 AA03 AA05 BE03

Claims (4)

[Claims] [Claim 1] as a main component Al ₂ O _3, Cr ₂
O ₃ 10 to 40 percent by weight, refractory material, characterized in that it contains 5-10% softening material which softens at 1000 ° C. or more by weight. 2. The refractory according to claim 1, wherein the softening material is soda lime glass. 3. The refractory according to claim 1, further comprising an oxide, nitride, carbide or boride of Al, Mg, Zr and / or Si. 4. A furnace, wherein the refractory according to claim 1 is provided on an inner surface of a furnace wall.