JPH0652153B2 - Refractory lining disassembly method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dismantling method performed prior to the construction of a furnace, a molten metal container, or other refractory lining for use in the steel manufacturing industry.

(Prior Art) For example, as a molten metal container lined with refractory,
For example, in the steel industry, containers such as tap gutters, mixed pig trucks, converters, ladles, and tundish consist of side walls and floors (lower parts),
Each is lined with refractory, most of which are permanent (perma lining) and lining (work lining)
It is composed of two layers. The work lining is directly or indirectly affected by the stored molten metal (eg, molten pig iron, molten steel) and molten slag, and is also damaged by contact, so it is used for a relatively short period (several days to several months). Since the remaining thickness of the work lining becomes thin, it is necessary to carry out refitting repair work.

Blast furnaces, converters, electric furnaces, and other furnaces have a structure in which refractory bricks are piled up, and it is common to extend the life by spraying repairs when the remaining thickness becomes thin, but at the end of the furnace It is necessary to dismantle the refractory bricks and reload them. During this repair work, of the lining,
The damaged work and its surroundings, that is, the remaining work lining within the repair required area must be destroyed, but the refractory of the remaining work lining is affected by the high temperature molten metal heat effect,
Alternatively, it is often hard to sinter both inside and outside due to the reaction with the invading molten metal and hot metal, and is often transformed into a so-called rock-like strong structure.

Therefore, the dismantling of the residual work lining is not easy, as the dismantling method, for example, as shown in JP-A-58-11379, a method of disassembling by injecting a static crushing agent into the refractory lining, Alternatively, as disclosed in Japanese Utility Model Laid-Open No. 58-79314, there is a method in which a piston is driven by compressed air and a refractory lining is disassembled by a back and forth movement of a hammer. The inventors of the present invention also used a disassembling method and apparatus utilizing high-pressure water (Japanese Patent Application No. 62-91286, Japanese Patent Application No. 62-91287, Japanese Patent Application No. 62-995).
No. 19, Japanese Patent Application No. 62-227758) has already been developed.

Thus, it is preferable that such a disassembling method does not involve a person and the work proceeds under almost fully automatic control. The dismantling work is performed in a bad environment such as high temperature and high dust, and the method of controlling the dismantling technique described above is necessary in consideration of the aging and labor saving of workers.

(Problems to be Solved by the Invention) As described above, the present inventors have already proposed a method of disassembling the refractory lining with ultra-high pressure water in a hot or cold state. According to these methods, hot spalling or hot dismantling utilizing the energy of steam explosively generated is far superior to cold dismantling in terms of dismantling ability. However, if the refractory linings of various shapes of molten metal containers are melted and damaged, the shape becomes complicated, and in order to operate the dismantling of such refractory linings by automatic control of the water jet nozzle, a highly sensitive visual sensor. It requires a precision instrument such as a movable arm or the like, and in particular, when used in a high temperature atmosphere, it becomes a large-scale device such as a cooling facility for the device, and cannot be a dismantling device that can be easily used anywhere at any time.

An object of the present invention is to dismantle fully and easily and effectively by presetting dismantling conditions in advance in accordance with the properties of the refractory lining part to be dismantled.

(Means for Solving the Problem) In disassembling the refractory lining with ultra-high pressure water, the present invention provides an interface between the zone A, the melt and the slag that is cured by exposing the part to be disassembled in advance to radiant heat from the melt. Corresponding to each of the above zones, it is classified into zone A, which has a large temperature change and large melting loss, is in contact with molten metal and molten slag, and has some metal remaining after the molten metal and molten slag are discharged. Then, the refractory lining is dismantled by operating and dismantling it under preset water jet impact conditions.

That is, the present invention, the degree of hardening, melting loss, damage of the refractory lining to be disassembled differs depending on the molten metal, the contact state with the molten slag, the heat-affected state, and the residual state of the metal, as described above. As described above, the zones are preliminarily distinguished from each other, the most preferable water jet impact condition is set for each zone, and the fishing operation is performed for each zone based on the respective set conditions.

Each zone to be divided will be described below.

The zone A is a part which is not always in contact with the molten metal or the like at normal times, but is cured by being exposed to a high temperature by the radiant heat from the molten metal. Normally, it is under the atmosphere, but it can be maintained in a non-oxidizing atmosphere if necessary. As described above, since this portion does not always come into contact with the molten metal or the like, a low-priced product can be used as the material of the refractory lining used. In the case of preventing atmospheric oxidation under a high temperature atmosphere, for example, a SiO ₂ refractory can form a vitrified layer and can suppress it. The strength of this part is relatively strong.

Zone B is a portion corresponding to the interface between the molten metal and the molten slag.
Although this part varies depending on the molten metal storage mode, there is a vertical movement of the interface in the process when the molten metal is stored, when the molten metal is processed, when the molten metal is poured, etc., and the temperature change in that area is large. Therefore, spalling is likely to occur, and the formed sintered layer peels off and is damaged. Further, melting loss occurs due to a contact reaction with the molten slag floating on the molten metal.
The refractory lining of this part is made of a refractory material having excellent spalling resistance and slag resistance, but the strength of the sintered layer formed during use has disappeared due to the damage and melting damage described above. Relatively weak.

The C zone is a region where the contact time with the molten metal is the longest and a part of the metal remains after the molten metal is discharged. Molten metal easily enters cracks or pores of the refractory lining at this portion, and metal adhesion cannot be avoided even after the molten metal is discharged. Further, since it is in contact with the molten metal for a long time and is over-sintered, the strength of this portion is the highest in each zone.

In the present invention, the water jet impact conditions are set according to the hardening strength of the refractory lining to be dismantled, melting / damaged state, residual state of metal, and the like.

Next, the setting conditions corresponding to each zone will be described.

Zone A has the least melting loss and is easily disassembled even by thermosetting, so the basic conditions for water jet are, for example, water pressure.
It can be easily hung at 1500 atm and a face-to-face distance of 50 mm.

Since the zone B strips off the reaction layer with the slag, it is necessary to use the most powerful water jet conditions. Basically, for example, it is preferable that the water pressure is 2500 atm and the surface distance is 20 mm, so that the water is slowly suspended.

In the C zone, when the metal is not mixed, it can be lifted at a water pressure of 2000 atm and the face-to-face distance of 20 mm. However, when the metal is mixed, the water pressure is, for example, 2500 atm and the amount of water is 8 mm.
/ Min, the nozzle moving speed is 0.5 m / min, and powder is preferably blown in at the same time as needed to form an abrasive cutting.

A concrete explanation will be given below by taking the gutter refractory lining of the blast furnace as an example.

The tapped hot metal and the blast furnace slag are separated from the difference in specific gravity with a gutter, and a perspective sectional view as shown in FIG. 1 is obtained. In the figure, 6 is the surface of the hot metal flowing in the large gutter, and 7 is the surface of the molten slag flowing while floating on the hot metal surface. The length of the gutter is annealed 1
Although it is 0 m, the cross-sectional properties shown in FIG. 1 are almost constant from upstream to downstream. The fireproof lining for a large gutter can be divided into three zones A, B, and C as shown in FIG. 1. For example, as shown in Table 1, different materials can be used for construction. That is, the zone A is a portion that hardly contacts the molten pig iron and the molten slag, the refractory lining is hardened by the radiant heat from the molten pig iron, and there is relatively little damage. The zone B is the portion corresponding to the interface between the molten pig iron and the molten slag. Therefore, the erosion of the contact surface with the slag is severe. In addition, when the hot metal is flowing, the amount of hot metal fluctuates, and the interface of the hot metal moves up and down during hot metal storage after tapping, so that the temperature change is severe and the damage caused by spalling is severe in the C zone. There is also a place where the metal remains in contact with the hot metal and the hot metal and the slag are still in contact with the hot metal when the hot metal is in storage.

The material is selected and constructed as shown in Table 1 so as to suit each of the A to B to C zones.

Since the fire resistant lining of Ohi usually wears out for 10,000 tons, it can be easily and effectively dismantled automatically by setting the dismantling conditions shown in Table 2 in advance for each zone. it can.

As with the Ohi lining, the materials for the hot metal truck, pot, etc. are selected so as to have a uniform erosion balance considering the slag line and hot water contact area. FIG. 2 shows a partially cutaway sectional view of the tow car. In the figure, 8 indicates the surface of the contained hot metal, and 9 indicates the surface of the molten slag floating on the surface of the hot metal. Zone A, which has almost no contact with the molten pig iron, is in contact with the molten pig iron and the atmosphere, and the contact with slag is a problem B
The zone and the zone C where it contacts with the molten pig iron and the metal remains in part are classified, and the materials shown in Table 3 are used.

Therefore, disassembling conditions can be easily and effectively fully disassembled by setting the disassembling conditions in advance for each zone as shown in Table 4.

(Example) Based on the method of the present invention, the following was applied to the fireproof lining of Ohi.
(A), (b), and (c) were installed under the appropriate dismantling conditions according to each zone. (B) Dismantling conditions for zone A in Fig. 1 Water pressure 1500 atm, face-to-face distance 50 mm, water volume 4 / min. It was possible to easily hang a thickness of 15 to 20 mm at a nozzle moving speed of 3 m / min.

(B) Dismantling conditions for zone B in FIG. 1 Water pressure of 2500 atm, face-to-face distance of 20 mm, water flow rate of 8 / min, and nozzle moving speed of 1 m / min were able to slowly hang a thickness of 25 to 30 mm.

(C) Dismantling conditions for zone C in Fig. 1 Since the metal was barely mixed, the water pressure was 2000 atm,
It was possible to obtain a thickness of 15 to 20 mm with a surface distance of 20 mm, a water amount of 6 / min, and a nozzle moving speed of 2 m / min.

The above disassembling conditions are set in advance, and control of the high-pressure pump in FIG. 1 and operation of the injection nozzle 2, the movable arm holding the injection nozzle 2, and the movable carriage 3 on which they are mounted are carried out while performing the lifting work. went.

When the entire surface is disassembled under the same conditions (comparative example-
Table 5 shows the results of comparison between 1) and the case of disassembling by disposing the visual sensor in the cold state (Comparative Example-2).

In Comparative Example 2, the refractory lining temperature was cooled to about 50 ° C, and the laser distance meter was used to maintain the face-to-face distance at 20 mm, while controlling the water pressure according to the hardness of the refractory lining.
Controlled between 1500 and 2500 atm. The hanging width was about 15 mm, and it was determined by the color sensor whether or not the sound layer was disassembled. According to this method, the dismantling material can be minimized to 21t because it is dismantled to the minimum required, but it takes longer to cool and the dismantling ability is lower in cold compared to hot. Is required to be as slow as 0.5 m / min, which is not preferable when compared with the method of the present invention.

(Effects of the Invention) As described above, according to the present invention, the refractory lining of the molten metal container can be easily and effectively disassembled in a hot state, and an appropriate disassembly condition according to the disassembly site is set in advance. Thus, the minimum necessary disassembly can be advantageously performed fully automatically without using a visual sensor that is weak to high temperatures.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment in which the present invention is applied to dismantling a fireproof lining of a gutter, and FIG. DESCRIPTION OF SYMBOLS 1 ... High-pressure water pump, 2 ... Injection nozzle 3 ... Mobile trolley, 4 ... Movable arm 5 ... Ohi lining

Claims (1)

[Claims] 1. When disassembling a refractory lining with ultra-high pressure water, the part to be disassembled is exposed to radiant heat from the molten metal in advance, and corresponds to the interface between zone A, molten metal, and molten slag, and the temperature changes greatly. , B zone with large melting loss, C that contacts molten metal and molten slag, and some metal remains after discharging molten metal and slag
A method for disassembling a refractory lining, which is divided into zones and is operated and disassembled under preset water jet impact conditions corresponding to each zone.