JPH085260A - Vessel for molten metal and method of using the same - Google Patents

Abstract

PURPOSE:To effectively prevent a metal from sticking to an inner face of a vessel for containing molten metal and easily peel the metal even in the case where it sticks to the inner face by forming the vessel with a heat-resistant material, spraying lime water to the inner face of the vessel and providing a peel layer on the inner face after drying the lime water. CONSTITUTION:A structural peel layer 2 wherein the peel layer 2 formed by drying lime water sprayed on an inner face of a vessel main body 1 made of a refratory material such as, for example, metal or ceramic is laminated on the inner face thereof is formed by spraying the lime water having a concentration of 25 to 30wt.% on the inner face of the vessel heated up to, for example, at least 250 deg.C at an inner face temperature and drying the lime water at the same time as application of the same. The drying time of the lime water is generally within 10 minutes. In order to reduce the drying time, a slag ladle to which the spraying of the lime water has been carried is heated to 270 to 350 deg.C. A method of spraying the lime water may be such a way that the lime water is uniformly sprayed onto the inner face of the slag ladle. The slag ladle, from which slag has been discharged, is subjected to treatment of spraying lime water again to the inner face of the ladle and is used for the discharge operation of molten slag.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improved container for containing molten metal and its use.
More specifically, the present invention relates to a container improved to prevent molten metal residue from adhering to the inner surface of a container containing molten metal, and a molten slag slag produced in a steel smelting process using this container. The present invention relates to a method for preventing adhesion of molten slag during processing.

[0002]

2. Description of the Related Art In the iron and steel smelting industry, slag is generated in each process from components other than iron in iron ore and from auxiliary raw materials used for smelting. As such slag, for example, blast furnace slag, converter slag, electric furnace slag, ingot slag (slag produced in the ingot making process), continuous casting slag (slag produced in the continuous casting process), desulfurization slag, decalcification slag, There is dephosphorization slag.

Conventionally, in a steel mill, as shown in FIG. 5, molten slag S generated during steelmaking is received from a ladle 3 into a ladle ladle 4 (A), and the ladle 2 is slag dump or slag truck 5. It is transported to the slag processing plant, and the slag pan is tilted to remove slag (B). However, the residual steel in the molten slag received in the Noro pot 4 during the transportation settles and adheres to the bottom of the Noro pot 4 as the metal M, but by tilting the Noro pot 4, it falls naturally. I can't throw it away. For this reason, the iron pot W hung by a crane or the like impacts the Noro pot 4 (C) and knocks off the deposits, but at this time, the hydraulic device of the slag dump 5 and the working mechanism are repeatedly subjected to the impact. Damaged and required regular repairs.

In order to solve such a drawback, a material mainly composed of natural graphite has been developed as a mold release material and is commercially available. However, this material is not always sufficient in mold releasability of slag. It has drawbacks such as high cost of mold material and high cost of slag waste treatment.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a heat-resistant container for containing molten metal, such as a ladle pan that receives molten slag generated in a steel smelting process, and metal is attached to the inner wall of the container. The purpose of the present invention is to provide a container capable of effectively preventing the above-mentioned phenomenon and easily peeling off even if it adheres.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventor has found that when a slag pan is repeatedly used for the treatment of molten slag and the metal contained in the slag. Paying attention to the fact that the Noro pot is always heated to a high temperature, if a low-concentration lime water of a specific concentration is sprayed on the inner surface of the Noro pot at a predetermined ratio, it will immediately dry and form a peeling layer of lime. The inventors have found that the object can be achieved, and have completed the present invention based on this finding.

That is, the present invention provides a container for molten metal, which is made of a heat-resistant material and has a peeling layer formed by coating and drying lime water on its inner surface, and utilizing this, a steel smelting process The present invention provides a method for preventing adhesion of metal in molten slag to a container at the time of waste slag treatment.

The present invention will now be described in more detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of an example of a container of the present invention, which is a release layer 2 formed by spraying lime water and drying the inner surface of a container body 1 made of a refractory material such as metal or ceramics. Has a laminated structure.

The peeling layer 2 has an inner surface temperature of 250 ° C., for example.
It is formed by spraying lime water having a concentration of 10 to 40% by weight, preferably 25 to 35% by weight, on the inner surface of the container heated as described above and drying at the same time as application. It is sufficient that the spraying amount at this time is 1 kg or more per 1 m ² of surface area of the inner surface.

The container with the peeling layer thus obtained contains the molten metal, does not remain adhered to the metal after being transported to a required place and discharged, and has a small amount of adhesion. Also, it can be easily removed only by giving a light blow.

This container is particularly advantageous for use in treating slag of molten slag generated in a steel smelting process.

According to this method, when the molten slag produced in the iron and steel smelting process is treated with slag using a refractory container, the inner surface of the container is preferably kept at a drying temperature, preferably 250 ° C. or higher, preferably 10 to 50 ° C. When lime water having a concentration of 40% by weight is sprayed at a rate of 1 to 5 kg in terms of solid content, it is dried almost at the same time to form a peeling layer made of lime, and then the molten slag is contained.

In this method, when the lime water is sprayed on the inner surface of a heat-resistant container such as a pot, the inner temperature of the pot is 2
It is preferably 50 ° C. or higher. If the temperature is less than 250 ° C, it may take too long to dry the lime water, or the desired lime layer may not be formed due to insufficient drying, and there is a risk of causing a steam explosion. . When the Noro pot is repeatedly used for the molten slag slag treatment, the inner surface temperature of the Noro pot generally depends on the temperature of the molten slag and the cycle time of the molten slag slag treatment, but is generally in the range of 270 to 950 ° C. And is at a temperature sufficient to dry the sprayed lime water.

The concentration of lime water used in the method of the present invention is selected in the range of 10 to 40% by weight, preferably 25 to 35% by weight. If this concentration is less than 10% by weight, it takes too much time to dry, and it is not practical because it does not completely dry and the desired lime coating is difficult to form, resulting in a marked decrease in work efficiency. High viscosity,
Nozzle is clogged during spraying. On the other hand, if it is more than 35% by weight, a surface disintegrant must be used in order to avoid a decrease in work efficiency due to an increase in viscosity. If it is less than 25% by weight, a drying step is required. 25 to 35% by weight.

Further, the spray amount of this lime water is in the range of 1 to ¹⁰ kg per 1 m ² of surface area of the inner surface of the ladle in terms of solid content. If this spray amount is less than 1 kg / m ² , the peeling residual rate is high, and the effect of preventing molten slag from adhering is not fully exhibited. If it exceeds 10 kg / m ² , the slag effect is reduced and the amount of lime scattered. Increase and bring about environmental pollution. The thickness of the lime layer at this time is about 1 mm, but this does not necessarily have to be uniform. The drying time of lime water is
It depends on the inner temperature of the pot, the concentration of lime water, and the spray amount of lime water, but it is generally within 10 minutes. In order to shorten the drying time, a drying process can be provided if necessary. In this drying step, the sprayed Noro pot is heated to 270 to 350 ° C.

The method of spraying lime water is not particularly limited as long as it is a method of uniformly spraying lime water on the inner surface of a ladle pan, and for example, a spray gun is used to mix lime water and compressed air. Then, a method of spraying by spraying in a mist state or an airless spray method of sending lime water by a high-pressure pump into a closed device and discharging the lime water from a converged nozzle and spraying it can be used.

In this way, the inner surface of the Noro pot is sprayed with lime water to form a lime layer, and then the molten slag is stored in the Noro pot and conveyed to a predetermined place by a slag dump. Tilt to discharge the slag. In this case, the slag is discharged almost without adhering to the ladle, or even if it adheres, it is easily peeled off with a small number of iron ball hits. The slag discharged slag pot is again sprayed with lime water on its inner surface to be used for the slag treatment of molten slag.

Next, a preferred embodiment of this method will be described with reference to the accompanying drawings. FIG. 2 shows the method 1
FIG. 3 is a flow sheet of an example, and FIG. 3 is a side view for explaining an example of an apparatus used in the spraying process of FIG. First, in FIG. 2, the slag dump from which the molten slag has been discharged travels to the front of the spraying device and stops there. Then, measure the wall temperature of Noro pot using, for example, a radiation thermometer,
Determine if the temperature is suitable for spraying lime water. As the wall temperature, the temperature of the inner wall that comes into contact with the lime water is required, but when it is difficult to measure the temperature of the inner wall, the temperature of the outer wall can be replaced with this. When this temperature is maintained at the required temperature (for example, 250 ° C or higher), lime water is sprayed, and if necessary, the ladle pan is tilted to remove excess lime water and completely dried. After confirming that it is done, dump up,
It will be placed again in the smelting furnace for the slag.

The above step of spraying lime water is carried out by the apparatus shown in FIG. That is, the slag dump 3 equipped with the ladle pan 2 is stopped at a predetermined position, lime is charged into the storage tank 8 by the flexible container 7 of the hoist 6, and a required amount of lime is dispensed from the storage tank 8 to the mixing tank 9. Prepare lime water by mixing with the required amount of water. While supplying this lime water to the liquid hose 11 with an underwater pump (not shown), the lime water is sprayed onto the inner surface of the pot 2 from the water spray nozzle 12 using the air pressure of the air hose 10. At this time, if the inner wall temperature is lower than 250 ° C., the lime water will be insufficiently dried, which may cause a steam explosion accident. Therefore, if the wall temperature of the Noro pot measured by the radiation thermometer 14 is below a predetermined value. It is preferable that the spray control timer 13 has a mechanism such that the submersible pump and the solenoid valve for air do not operate.

FIG. 4 is a system diagram for explaining the working mechanism of an example of a lime water spraying device. In the first step, the radiation thermometer 14 measures the wall temperature of the pot 2, In step, the measured value is output to a printer and the temperature and date and time are recorded. Further, in the third step, when the measured value in the first step is lower than the required temperature (for example, 250 ° C.), the alarm is activated in the fourth step and the fifth step is performed.
In step, the spray control timer 13 is turned off,
The spraying work of lime water is stopped.

On the other hand, if it is confirmed in the third step that the measured value in the first step is 250 ° C. or higher, the circuit is connected in the sixth step, and the starting condition of the spray control timer is determined in the seventh step. It is determined that the condition is satisfied, and the timer is turned on in the eighth step. As a result, the submersible pump operates for the required time (for example, 10 seconds) in the ninth step, and the air solenoid valve operates for the required time (for example, 5 seconds).
Then, the required amount (for example, 15 liters) of lime water is sprayed, and the spraying is completed in the tenth step.

[0022]

Next, the present invention will be described in more detail with reference to examples.

Example 1 A ladle pan having a capacity of 7.5 m ³ and an inner surface area of 3.4 m ²
The test was performed using the Noro pot. First, about 1300 ℃
The melted slag was stored in a Noro pot and transported by a Noro dump to a slag treatment site about 0.8 km away (conveyance time about 5 minutes), and the Noro pot was tilted to discharge the slag. At this time, since the slag adhered and remained on the inner surface of the Noro pot, it was completely peeled off by hitting with an iron ball and discharged.

Then, 6 liters of lime water having a concentration of 30% by weight was sprayed on the inner surface of the pot for 10 seconds with an air gun to dry it. The spraying amount at this time was 0.52 kg / m ² in terms of solid content. Further, after the spraying was finished, the generation of water vapor was stopped and the surface was cracked, so that the drying was completed. The inner surface temperature of Noro pot and the drying time before spraying lime water were measured.

Next, the noro-dump is run to the place where the ingot-making slag is generated, and the ingot-melting slag melt is again stored in the noro-pot. It was discharged. At this time, when the slag adhered and remained, the slag was peeled off by hitting with an iron ball and discharged. Then, in the same manner as above, after spraying the lime water on the inner surface of the Noro pot, the molten slag was removed from the slag. This operation was repeated 100 times.

With respect to a Noro pot sprayed with lime water, the number of times slag adheres to the Noro pot is expressed as a percentage,
Further, the average number of times of tapping when the slag attached to the Noro pot was peeled off by hitting with an iron ball was obtained. Table 1 shows the results.

Examples 2 to 4 The same operation as in Example 1 was carried out except that the amount of lime water was changed to 10 liters, 15 liters and 20 liters. The results are shown in Table 1.

When the amount of lime water was 10, 15 and 20 liters, the required spraying time was 15 seconds, 20 seconds and 30 seconds, respectively.

[0029]

[Table 1]

As can be seen from Table 1, there is a clear correlation between the spray amount and the peeling effect, and the peeling effect becomes more remarkable as the spray amount is increased. Convert lime water to solid content 1.
When sprayed at 76 kg / m ² (Example 4), it was found that 96% was capable of spontaneous slag.

Comparative Example The same operation as in Example 1 was carried out except that the spray treatment of lime water was not carried out. As a result, in all the slag slag treatments, the slag adhered to the slag pot (slag adhesion rate 100%), and the average number of times of beating to separate the slag was 5 or more.

Example 5 In the same manner as in Example 1, 50 liters of lime water having a concentration of 40% by weight was sprayed on a Noro pot having an inner wall temperature of 350 ° C. to form a lime layer. At this time, the solid content converted spray amount was 6.5 kg /
m ² . Further, the average lime water drying time was 120 seconds, and the adhesion of slag and metal was hardly observed.

[0033]

INDUSTRIAL APPLICABILITY In the container for molten metal of the present invention, bare metal is hardly adhering after containing and discharging molten metal, and even if a small amount is adhered, it can be removed by applying a slight impact. Therefore, by utilizing this, it is possible to effectively prevent the adhesion of the slag and the metal to the Noro pot for transporting the molten slag generated in the steel refining process.

[Brief description of drawings]

FIG. 1 is a sectional view of an example of a container of the present invention.

FIG. 2 is a flow sheet of the method of the present invention.

FIG. 3 is a side view for explaining a spraying device of the method of the present invention.

FIG. 4 is a system diagram showing an action mechanism of an example of a spraying device used in the method of the present invention.

FIG. 5 is an explanatory view showing a step of removing a deposit on a conventional ladle pan.

[Explanation of symbols]

 1 Container body 2 Lime layer 3 Ladle 4 Noro pot 5 Slag dump

Claims (2)

[Claims] 1. A container for molten metal, which is made of a heat-resistant material and has a release layer formed by spraying and drying lime water on the inner surface thereof. 2. When the molten slag produced in the iron and steel smelting process is treated with slag using a heat-resistant container, lime water is sprayed on the inner surface of the container kept at a drying temperature to almost simultaneously dry the lime. A method for preventing adhesion of metal in molten slag, which comprises forming a peeling layer.