JP3404626B2 - Coating method for refractory wall in rotary melting furnace - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating a refractory material on a refractory wall in a furnace in a rotary melting furnace for melting waste and the like.

[0002]

2. Description of the Related Art A rotary melting furnace is a melting furnace in which an object to be treated such as waste that has been charged from one end is melted while moving toward the other end, and is discharged as molten slag or exhaust gas from the other end. This is a melting furnace using a so-called rotary kiln of a type. Generally, rotary kilns are used for cement burning, but in recent years, they have also been used for melting and treating incinerated ash in refuse treatment plants and the like, and dusts containing valuable metals in ironworks.

When the rotary kiln is used as a melting furnace, it naturally has a high temperature, and therefore the inner wall is made of a refractory wall such as refractory brick. However, even though it is a fire wall,
As a result of long-term operation, it is inevitable that normal or abnormal wear will occur on the refractory wall due to various causes such as melting damage or local heating, and also wear due to chemical reaction with the molten slag of the workpiece. Also occurs. Then, when the amount of wear becomes significant, it is necessary to replace the refractory wall.
Replacing the refractory walls not only costs materials and construction costs, but also causes losses due to the decommissioning (about 2 weeks), and dismantled refractory bricks become new waste.

[0004]

Therefore, in order to reduce the amount of wear of the refractory wall as much as possible, it has been proposed to use a high temperature refractory material or to coat the refractory wall with a coating material of a refractory material. . According to this proposal, in the former case, the refractory material is expensive, and depending on the object to be treated, it is not so effective in melting damage due to a chemical reaction. In the latter case, the coating operation is performed in a state where the melting process of the object to be processed is temporarily stopped. That is,
The molten coating material is coated on the refractory wall by utilizing the fact that the coating material is put into a high temperature furnace and the furnace is rotating.

By the way, as a coating material for a refractory wall of a rotary type melting furnace, a vitreous material (main component is SiO ₂ ,
Na) and earth and sand (main component SiO ₂ ) have been proposed.
However, since SiO ₂ easily forms a eutectic with a low melting point with other metal oxides, the life of the coating layer is short, and the slag in which much SiO ₂ is melted has a high viscosity in a wide temperature range, so It is difficult to make the layer thickness uniform.

[0006] Therefore, an object of the present invention is to provide a coating method in which the life of the fireproof wall can be extended by extending the life of the coating layer.

Another object of the present invention is to provide a coating method capable of making the coating layer thickness uniform.

Still another object of the present invention is to provide a coating method capable of effectively utilizing a refractory material which is generated when a refractory wall is replaced in a melting furnace and is originally a waste.

[0009]

According to the present invention, there is provided a coating method for coating a refractory material on a refractory wall in a furnace in a rotary melting furnace while rotating the furnace, wherein the melting process during operation is temporarily suspended. The molten material slag to be treated is retained in the furnace, the molten slag to be treated is heated to a temperature range higher than the normal operating temperature, and the melting point is higher than the melting temperature of the material to be treated in the furnace. And a step of supplying an additive material containing a high content component, the method for coating a refractory wall in a rotary melting furnace.

The additive material is preferably a refractory material containing alumina as a main component.

As the additive material, a crushed product of refractory brick scraps obtained at the time of dismantling a refractory wall in a furnace such as a melting furnace is used to reduce waste and prolong the life of the refractory wall. be able to.

The temperature range higher than the normal operating temperature is preferably in the range of 1500 to 1600 ° C.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In a normal rotary type melting furnace, as an object to be treated, incinerator ash in a refuse incinerator or the like or dust generated in an iron mill or the like is charged with coke or coal and heated and melted. Slag and discharge. At this time, when mainly treating incinerated ash of a refuse incineration plant, the components of raw slag are calcia (CaO) and silica (SiO ₂ ), and the melting temperature thereof is about 1200 ° C.

When the object to be treated is melt-processed in this manner, the refractory material is worn out normally or abnormally with time.

An embodiment of the method for coating a refractory wall in a rotary melting furnace according to the present invention will be described below. The coating method according to the present embodiment is carried out through the following steps in a state in which the inside of the furnace is maintained at a high temperature without bringing the rotary melting furnace into a closed state.
Of course, the furnace remains rotating.

The melting process, that is, the introduction of the material to be treated into the furnace is temporarily interrupted, and the molten slag is retained in the furnace.

The slag temperature is 100 to 100% higher than that during normal operation.
Raise the temperature by 300 ° C. Therefore, when treating the incineration ash of a refuse incineration plant, it heats to 1500-1600 degreeC.

The additive material containing alumina is gradually supplied from the waste input port.

Then, alumina melts into the slag and the melting point of the slag rises.

The molten slag in which alumina has melted adheres to the surface of the refractory wall (inner peripheral surface of the furnace body) due to the rotation of the furnace, and when the melting point of the slag exceeds the holding temperature, it solidifies and becomes fire resistant. A coating layer is formed on the surface of the wall.

The additive material may be a refractory material containing 80 to 90% of an alumina component, but in this embodiment, a crushed product of alumina-based brick waste (particle size of 1 mm or less is preferable) is used. Such brick waste may be not only brick waste generated when the refractory wall is replaced in the rotary melting furnace which is the subject of the present invention, but also brick waste generated as waste when the refractory wall is replaced in a normal melting furnace.

The above coating principle will be briefly described. The molten slag in the rotary melting furnace contains SiO ₂ , CaO and Al ₂ O ₃ as main components. Figure 1
SiO _2, CaO, and a diagram showing the melting point changes in that depending on the composition of the material mainly composed of Al ₂ O _3, tends to rise the melting point the components of each vertex is increased. On the other hand, it is known that the composition of the slag of the melting furnace that treats the incineration ash generated in the refuse incinerator as the main object to be treated is usually within the region A in FIG. The melting point in the region A is 1200 to 14
It is in the range of 00 ° C. On the other hand, when the alumina component is increased (in the direction shown by the arrow in Fig. 1), the melting point is 1500 ° C.
Rise above. Therefore, the molten slag for the object to be processed is 150
Maintaining a high temperature of 0 ° C or higher, preferably 1500 to 1600 ° C to increase the saturation solubility and then melt the refractory material for coating to lower the viscosity to make it easier to adhere to the surface of the refractory wall in the furnace. The principle of coating according to this embodiment is to finally solidify.

As can be seen from FIG. 1, the temperature of alumina rises to the melting point faster than other components. In other words, the time to reach the melting point is short. That is, the use of alumina as the coating material means that the coating layer can be formed with other components.
In addition, since it is difficult to form a low melting point eutectic with other metal oxides, the life of the coating layer is extended.

[0024]

As described above, according to the present invention,
By using a material containing alumina as the coating material, the coating layer can be formed in a short time and the life of the coating layer is extended. Also,
It is possible to reuse the brick scraps generated during the dismantling of the refractory wall in the melting furnace, and suppress the generation of waste.

[Brief description of drawings]

FIG. 1 is a diagram showing a change in melting point depending on the composition of a material containing SiO ₂ , CaO, and Al ₂ O ₃ as main components.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F23G 5/00 ZAB F23G 5/00 ZAB 5/44 ZAB 5/44 ZABD F23M 5/00 F23M 5/00 H (58) Field (Int.Cl. ⁷ , DB name) F27B 7/28 C10B 29/06 C10B 47/30 C10B 53/00 F23G 5/00 115 F23G 5/00 ZAB F23G 5/44 ZAB F23M 5/00

Claims (4)

(57) [Claims] 1. A coating method for coating a refractory material on a furnace refractory wall in a rotary melting furnace while rotating the furnace, wherein a melting process during operation is temporarily interrupted to melt a material to be treated slag in the furnace. And the step of heating the accumulated molten slag of the material to be treated to a temperature range higher than the normal operating temperature, and supplying an additive material containing a component having a melting point higher than the melting temperature of the material to be treated into the furnace. A method for coating a refractory wall in a rotary melting furnace, comprising: 2. The method for coating a refractory wall in a rotary melting furnace according to claim 1, wherein the additive material is a refractory material containing alumina as a main component. 3. The rotary melting furnace according to claim 1, wherein, as the additive material, a crushed product of refractory brick scraps obtained at the time of dismantling a furnace refractory wall of a melting furnace or the like is used. For coating fireproof walls in Japan. 4. The coating method according to claim 1, wherein the temperature range higher than the normal operating temperature is 1500-500.
A method for coating a refractory wall in a rotary melting furnace, which is in the range of 1600 ° C.