JPS6259387A - Method of removing slag - 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] [Industrial Application Field] The present invention relates to a method for removing slag, and in particular to refractories used in containers for various molten metals, molten metal sluices for blast furnaces, lance pipes for gas injection, etc. This invention relates to a slag removal method that can efficiently remove slag adhering to a surface and only remove the slag portion.

[Conventional technology] In recent years, steel mills, etc. have been trying to reduce the amount of refractories used.
In order to reduce equipment costs, etc., refractory surfaces such as hot metal furnaces, etc.
That is, the lining layer has been subjected to various repairs so that it can continue to be used for as long as possible.

In the repair of refractories, pouring repair and spraying are usually performed, but if slag adheres to the surface to be repaired during repair, the adhesive strength of the repair material will be significantly reduced. In other words, in cold conditions, slag on the surface of a refractory often adheres to the refractory with weak force, and even if a repair material is applied to the surface to which such slag has adhered, strong adhesion cannot be obtained. There isn't. Furthermore, when the slag layer is exposed to hot water such as molten steel after the repair work is completed, the slag layer softens due to its low melting point, which often causes the repair material to peel off.

Conventionally, several methods have been proposed for removing slag from the surface of refractories. For example, a method of scraping off the slag using a large crusher, and a method of driving a chain along the slag surface to scrape off the slag. is proposed.

[Problems to be Solved by the Invention] The method of scraping off slag using a large crusher has the disadvantage that although large slag, that is, a thick slag layer, can be easily removed, it is extremely difficult to remove a thin slag layer. The large crushing force of the machine may scrape off even large pieces of base material on the back of the slag, or destroy the refractory structure.
It has the disadvantage of having a negative effect on the base material. In addition, automation was extremely difficult because the tip working section of the crusher directly applied force to the slag.

Further, the method of scraping off slag by driving a chain is difficult to automate for the same reason, and requires a large device, so it cannot be said to be a practical method.

For this reason, the current situation is that workers rely on manual removal of slag using breakers, which is a problem in the working environment.

There are major problems in terms of work efficiency, etc.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned conventional problems, and involves injecting solid particles against a surface to which slag is attached, and using the energy of the collisions. This removes the lag.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a sectional view illustrating the slag removal method of the present invention. In FIG. 1, 2 is the steel shell of the molten metal container 1, 3 is the safety liner, 4 is the inner lining, 5 is the adhering slag, and 6 is the laying brick.

The method of the invention involves jetting solid particles at high velocity towards the adhered slag to be removed. The injection of solid particles may be performed, for example, in the first
This can be done automatically and very easily using an injection device as shown in the figure.

That is, the solid particles 8 stored in the hopper 7 are transferred to the transportation hose 10 by compressed air from the compressor 9.
The slag 5 is conveyed through the slag 5 and is injected from the injection nozzle 11 toward the slag 5. 12 is a drive unit for rotating and raising/lowering the injection nozzle shaft, and by operating the drive unit 12, the solid particles 8 from the injection nozzle 11 are transferred to the container l.
The slag is sprayed toward all parts of the inner wall surface, and the energy of the collision can evenly remove the adhered slag.

The injection speed of solid particles varies depending on the size of the solid particles, etc., but if the injection speed is low, the slag removal effect will be low, and if the injection speed is too high, the pneumatic transportation energy will increase, making it uneconomical. .

Although the type of the injection nozzle 11 is not particularly limited, it is preferable to use a commercially available sandblasting nozzle for metal surface treatment.

The solid particles to be injected are not particularly limited and any particles can be used, but particles of alumina and magnesia, which are refractories, and steel balls are particularly suitable. In addition, slag itself produced in steel works is also effective as a material for solid particles. When using slag particles, there is an advantage that the removed and recovered slag can be used as is as an injection material. At this time, particle size adjustment may be necessary in some cases, but normally it can be reused as is without particle size adjustment.

Furthermore, if the size of the solid particles is too small, the slag removal effect will be low and the problem of dust generation will occur. On the other hand, if the particles are too large, the energy required for air transport for injection and the suction energy for collection as described below will be large.
This is undesirable, and the collision speed tends to be small, which may reduce the removal effect. Therefore, in the present invention, the preferred particle size of the solid particles is 0.5 to 5.
The range is 0mm.

According to the apparatus shown in FIG. 1, slag can be removed with relatively less power than conventional methods, and the apparatus can be made smaller.

The collection of solid particles injected toward the slag adhesion surface and the slag that has fallen off due to the collision of the solid particles can be easily and automatically performed by vacuum suction. This may be carried out later, or it may be carried out in parallel with the removal work by providing a vacuum suction tube around the injection nozzle 11.

After separating the collected solid particles and slag as necessary,
It is reused, but separation is done by air-geparato.
r) can be easily performed. When steel balls are used as the solid particles, magnetic separation can also be used.

According to the method of the present invention, adhered slag can be removed extremely efficiently, and the removal work can be easily automated. By adjusting the injection speed, injection amount, etc. of the solid particles, it is possible to easily remove all types of slag, from thick to thin layers.

After removing and recovering the slag, the exposed inner lining 4 is repaired according to the usual method such as pouring repair, as shown in Figure 2.
The repair material 13 is applied to the surface of the lining after the slag has been removed by the method of the present invention, and the surface has fine irregularities. Glue.

The slag removal method of the present invention can remove slag that adheres to the surface of refractory linings used in molten metal containers, blast furnace hot metal buckets, lance pipes, etc. used in steel plants, as well as all other parts. It is extremely effective in removing slag.

[Function] The slag removal method of the present invention removes slag using the energy of collisions of solid particles, so compared to conventional mechanical removal methods, the working part of the device does not come into direct contact with the slag. , easy to automate. Furthermore, by adjusting the impact force, slags of various sizes can be easily removed without damaging the base material.

By the method of the present invention, the surface from which the slag has been removed has fine irregularities, so that the repair material will firmly adhere to it due to the anchoring effect.

[Example 1 Examples will be described below.

Example 1 Slag adhering to the inner wall of a ladle (slag line, capacity 270 t) was removed by the method shown in FIG.

Steel balls with a particle size of 2.5 to 3 mm were used as the solid particles, and they were blasted at 75 kW with a commercially available sandblasting nozzle.
It was sprayed onto the slag surface using a 12 m''/min compressor. The nozzle was driven automatically. Also, the temperature of the treated surface at this time was 70 to 80°C. It was recovered by adsorption.

The ladle has an inner wall of about 3.8rn', 5-15mm.
Although a thick layer of slag had adhered to the ladle, the slag on the inner wall surface was almost completely removed after 32 minutes of solid particle injection, and the base material (castable (zircon)) of the inner wall of the ladle was not damaged in any way. The amount of solid particles used at this time was 256 kg (
The amount used per unit area was 67.4 kg/m'').

After removing and recovering the slag, the inner wall of the ladle was repaired by pouring, and the repair material adhered extremely firmly.
The repair material did not peel off during use of the ladle.

Examples 2 to 4 According to the method of the present invention, slag adhering to the inner wall of a tap trough (slag line) (Example 2) or an electric furnace ladle (Example 3.4) was removed.

Specifications of the target to be treated, solid particles, etc. are listed in Table 1 along with those of Example 7.

After slag removal and collection, pouring repair (Example 2)
Alternatively, when the inner wall base material was repaired by patching repair (Example 3.4), the repair material adhered extremely firmly and did not peel off during use.

From Examples 1 to 4, it is clear that according to the method of the present invention, slag can be efficiently removed in a short period of time, and repair after removal can be performed extremely well.

[Effects] As detailed above, the slag removal method of the present invention injects solid particles toward the surface on which the slag is attached, and efficiently removes the slag using the energy of the collision.

■ Even a thin slag layer can be easily removed without damaging the base material.

■ Easy to automate.

■ The repair material will firmly adhere to the surface after removal due to the anchoring effect.

■ Compared to conventional methods, removal can be performed with less power, so the equipment can be made smaller.

It has many advantages.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a molten metal container and solid particle injection device for explaining the slag removal method of the present invention, and Fig. 2 is a cross-sectional view of a molten metal container that has been repaired after removing slag according to the present invention. It is a diagram. l...container for molten metal, 2...iron shell, 3...safety lining, 4...lining, 5...attached slag, 6...laying bricks, 7...hopper,
8...Solid particles, 9...Compressor,
10... Transportation hose. 11... Injection nozzle. 12... Nozzle drive unit, 13... Repair material.

Claims (3)

[Claims] (1) A slag removal method characterized by removing slag by ejecting solid particles toward a slag adhesion surface and causing them to collide. (2) The method for removing slag according to claim 1, wherein the solid particles have a particle size of 0.5 to 5 mm. (3) The solid particles are one or two of steel balls, magnesia grains, alumina grains, silica sand, blast furnace slag, converter slag, and SiC.
The method for removing slag according to claim 1, which comprises more than one type of slag.