JPS5885090A - Method of reinforcing lining of kiln by water plasma flame spraying device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention relates to a method for reinforcing parts that are susceptible to damage in each stowage reactor. Or, after building bricks manufactured using conventional methods, water plasma spraying equipment is used to form a sprayed layer on the surface of the bricks in areas that are likely to be damaged, thereby reinforcing the bricks.
Balance the damage to each kiln and extend the life of the kiln! Regarding how to extend.

A refractory lining is used in each of the oak kilns used in high-level industries such as iron manufacturing, non-ferrous metal refining, cement manufacturing, and kiln leaf raw material manufacturing, but the degree of damage to the refractory lining varies depending on where it is used.

The degree of damage to the inner lining used in the slag line section, steel bath section, bottom section, etc. of the slag line section, steel bath section, bottom section, etc. of port melting metal containers, such as converters and drawers, etc., differs depending on the degree of damage, so the damage balance should be carefully considered before use. Furnaces have been constructed by changing the material and thickness of the heavy-duty materials, but even so, the damage cannot be balanced, so countermeasures such as repair using monolithic refractories such as barking and patching are taken during use. ing. It is impossible to unnecessarily increase the thickness of the refractory layer as a measure against this local damage due to the content of the molten metal container, and when repairing using soft materials, etc., the temperature at which molten metal sm can be applied is In some cases, it may be necessary to preheat the product to near the operating temperature after repairs are completed, which is not only undesirable from an efficient and economic perspective, but even with these measures, local damage may still occur. The lifespan of the molten metal container is often affected.

In addition, in rotary kilns used for firing cement and industrial raw materials, corrosion resistance, abrasion resistance, and spalling resistance are particularly required in the firing zone, which is the highest temperature.
Although high-quality and inexpensive bricks such as Maguro It and Keisei Maguro bricks are used, they are not satisfactory from the overall damage balance. Furthermore, in rotary kilns, expansion allowances are taken in the axial and circumferential directions of the kiln using cardboard or the like, which may cause bricks to fall off in the early stages of operation. This prevents it from falling off during the initial stage of operation. However, when joint iron plates are used, expansion and contraction during the cycle of operation and rest may cause impregnation of the kiln shell and backing of the bricks, and the contact of molten iron plates with the iron bricks may weaken the brick structure and cause damage. was inviting. In addition, in the case of coatings, the adhesion of the coating depends on the properties of the bricks used, such as their porosity and chemical composition. The contradictory results were that the adhesion was good.

The damage mechanism of each phase kiln lining is thought to be divine, but one of the main damage mechanisms of the refractory lining is molten metal,
Melt liquid such as molten slag or gas such as alkali vapor or acid gas diffuses into the pores of the large-sized material and reacts with it (11) to generate low melting point substances and volatile substances, resulting in detachment damage.

(21) A degraded layer is generated, and due to the difference in thermal expansion coefficient, etc., the degraded layer cracks and peels off due to subsequent heating and cooling, resulting in damage.

Chemical damage such as The pores of the refractory are involved in this damage, and the higher the porosity and the larger the pore diameter, the more the damage will be accelerated. In addition, the smaller the porosity is, the better against the wear and tear caused by bath-metal and solid cedar interlayer formation.

Therefore, by lowering the porosity of large-sized materials and reducing the pore diameter,
Many attempts have been made to improve the durability of refractories.

For example, methods are being used to obtain dense molded bodies by reducing the particle size of the raw materials used. However, lamination may occur during molding, expansion during firing, etc. Cracks may occur due to the noodles, and the volume stability may be inconsistent.

In addition, methods using flame spraying and gas plasma spraying, which have been attracting attention in recent years, were also considered, but flame spraying requires the use of refractory raw materials with a high melting point because it is difficult to increase the flame temperature too high. Therefore, it was not possible to use a highly durable product. On the other hand, with gas plasma spraying, it is possible to obtain high temperatures and use refractory raw materials with high melting points, but the spraying capacity is small, the spraying range is narrow, and the thickness of the coating layer formed may also be small. Practically speaking, it is only about 11 m11 or less, and furthermore, it has economic disadvantages such as using an expensive gas such as helium argon as the working gas, and fully satisfactory results have not been obtained.

Therefore, as a result of conducting a study on the above-mentioned matters, the inventors and their team found that the thermal spraying ability is extremely large compared to gas plasma spraying, and the spraying range is wide, in order to spray the areas that are easily damaged in each mildew reactor. The coating thickness reaches a practical thickness of 30 m, and the lining material has a sprayed coating layer formed using water plasma spraying, which is economical because it uses inexpensive water instead of expensive working gas. As a result, a dense thermal spray coating 11
The porosity of 1111 is extremely low, the pore diameter is extremely small, and the adhesion to the base material is also extremely good, making it highly durable, balancing damage to the lining material, and creating a long-life kiln. This discovery led to the completion of the present invention.

That is, the present invention is a method for reinforcing a kiln lining in which the parts of the kiln of each kiln that are susceptible to damage are formed with a lining material having a thermally sprayed coating layer using a water plasma spraying device. The first m* method involves applying water plasma to each kiln, sometimes a molten metal container, a rotary kiln, and other localized lining parts, on the surface that is the operating surface of the conventionally used lining brick. This is a method of building a furnace using bricks that have been sprayed with a refractory material and formed with a dense thermally sprayed layer (hereinafter simply referred to as the layer). This will be explained using an example. The part that is susceptible to local damage is a when receiving steel.
Examples include the m-ri part, the slug line part, and the st tuyere part,
First, a refractory material with excellent corrosion resistance against molten steel and molten slag is sprayed on the surface of the bricks to be built in these parts, which will be in contact with the molten slag, using a Sun F blast plasma spraying device to form a coating layer (Fig. 1). By building the furnace using these bricks, the durability of the parts that are easily damaged is improved, the overall melting balance is balanced, and the furnace is constructed using these bricks.
It is possible to extend the special mission of I.

The second reinforcing method of the present invention is to construct 8111I by the conventional method on the lining part of each mu furnace that is susceptible to chest damage.
This method uses a water plasma spraying device to thermally spray a refractory material onto this area, forming a dense adhesion layer on the surface of the refractory lining.

To further explain this method, after the furnace is built, a gate protrusion is added to the side part to be reinforced by surface treatment such as sandblasting, or after the furnace is built, the brick surface that is the inner surface is blasted. As shown in Fig. 2, a coating layer of the required thickness is formed using a water plasma spraying device.

In particular, when thermal spraying is applied after construction, the joints of the bricks are also uniformly coated, making it an optimal method for reinforcing materials and parts that are susceptible to joint erosion.

Furthermore, if the present invention is continuously applied after the construction of a rotary kiln, the thermal sprayed layer will integrate the kiln, which will not only improve durability due to corrosion resistance and wear resistance, but also prevent bricks from falling off. Shiba becomes unnecessary.

Next, the water plasma spraying equipment used in the present invention is not particularly limited, and the refractory material to be thermally sprayed is a refractory material made of the same material as the base material (hereinafter simply referred to as the base material), or a refractory material that is used. It reacts with the base material at the temperature of
Any refractory material that does not easily generate lJI properties, has a coefficient of thermal expansion that is significantly similar to that of the base material, and does not cause peeling between the base material and the coating layer when the temperature rises can be used.

This method using water plasma spraying can also be applied to repair damaged areas during use as an intermediate repair for various furnaces; It is also advantageous from the point of view of furnace operation to thermally spray the area and thickness based on the preheating of the furnace.

As described above, the reinforcing method of the present invention provides the following effects.

111 Since a highly corrosion-resistant coating layer is formed using a water plasma spraying device, the melting loss of the lining material can be balanced and the life of the furnace can be extended.

(Since a highly corrosion-resistant laminated layer is formed using a 21 water plasma spraying device, the erosion and damage of the lining material is balanced,
Intermediate repairs are no longer necessary or the number of repairs is reduced, resulting in stable furnace operation.

(3) Since water plasma spraying equipment is used, it is possible to spray thicker materials and spray over a wider area than gas plasma spraying equipment, and it is also economically advantageous compared to gas plasma spraying. A coating layer can be formed on the surface.

Example After the surface of each of the zircon and alumina bricks was sandblasted to create irregularities, a refractory material of the same material as the base brick was sprayed onto each brick using a water plasma spraying device to a thickness of 10#. Table 1 shows the physical properties and chemical composition of the layer and the bricks that formed the layer.

In addition, the pore pole distribution was determined using a mercury intrusion porosimeter.
Figures (shown in Figures 11-4I).

Thermal Spraying 11 - Damage to bricks caused by molten steel and molten slag was investigated. Thermal spray layer - Brick I! Using 8 pieces each of 2 types of base material bricks without thermal spraying** for comparison, we assembled a sardine hemlock-shaped gluing type numberer with an inner side of 505w, a thickness of 301mm, and a paddle length of 170cm. After adding 2δOg of Yu-10 lithium slag (#A base illuminance 3L) in a bleaching furnace and holding it at 16ffio℃ for 8 hours, the wear dimension of the sample and the invasion state of Bath-1 molten slag were measured. -Bet. The results are shown in Table 2. In addition, the wear dimensions are the same as the slag line part.
These are the average values of two samples for each part.

Cocoon Table 2 Molten steel, molten slag test - The molten layer formed by water plasma spraying equipment is denser and *1lIll compared to the base material, so molten steel,
The wear against molten slag is extremely small, and the thickness of the altered layer due to the penetration of molten steel and molten slag is also very small, so it is clear that it exhibits extremely high corrosion resistance. Therefore, when this is used for internal reconnaissance, damage can be balanced and the life of the furnace can be extended.

Example 2 Rotary kiln for firing stabilized dolomite clinker for refractory materials (length 80 mm, inner pole 1.7 m, outer diameter 2.3
26 pieces of fired tuna brick (MgO70
magklic acid powder to a thickness of 2 mm using a water plasma spraying device.
The furnace was constructed by separately placing bricks with a 0m++ thermal sprayed layer and bricks without any thermal spraying. Calcining of stabilized dolomite was operated for 25 days (540 hours of actual operation), and the temperature of the calcining zone was 1700 to 1900 °C. After the completion of the operation, the damage condition of the bricks with the thermal sprayed layer was compared with the bricks without the thermal sprayed layer. The results are shown in Table 3.

Table 3 Results of use in a rotary kiln The structure of the sprayed layer formed in this example is strong and dense, and has excellent wear resistance. In this way, the reinforcing method of the present invention can balance damage and extend the life of the rotary kiln.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an example in which a thermally sprayed layer is applied to a brick surface according to the present invention. FIG. 2 is a cross-sectional view of an example in which thermal spray lI411 was applied to areas susceptible to damage after furnace construction according to the present invention. No. 311 is a diagram showing the pore size distribution of the base material brick and the interlayer used in Example I, (11 is the arsena layer, 121 is the zircon base material, (2) is the alumina mass material brick, 141 indicates a zircon base material brick. z-m-base material brick 2-sprayed AAT layer 3---permanent brick Hiro・-iron skin

Claims (1)

[Scope of Claims] L. A method for reinforcing the lining of a kiln, characterized in that, before the kiln is put into operation, parts of the kiln that are susceptible to damage are formed with a lining material that is coated with a thermally sprayed layer using a water plasma spraying device. . 2. The reinforcing method according to claim S, No. 1111, characterized in that the lining is made of bricks that have been thermally sprayed with flINRT in advance using a water plasma spraying device. 3. A reinforcing method according to claim 1, characterized in that after the lining is constructed, a thermal spray coating is formed using a water plasma spraying device.