JP3021946B2 - Cooling method for high temperature steelmaking slag - 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 cooling high-temperature steelmaking slag. Steelmaking slag is generally C
aO content, f. 1% or more is present in the form of CaO. After solidifying this high-temperature steelmaking slag of 200 ° C. or higher, it is charged upward onto a plate in a closed container, and 0.5 to 4 m
After filling and sealing, the slag-filled layer is
Watering the cooling water at a watering density of ３０30 ton / hrm ² ,
An object of the present invention is to provide a means for promoting the hydration reaction of slag in a closed container and at the same time obtaining a crushing effect.

[0002]

2. Description of the Related Art In a usual steelmaking slag treatment, slag is first discharged onto a pit or an iron plate to perform solidification and cooling.

[0003] After the cooling is completed, the crushed slag is crushed to a required particle size by a crusher, and the crushed slag is passed through a magnetic separator to recover iron, and then used for roadbed material, landfill, and the like.

However, the above-mentioned cooling, crushing, and magnetic separation treatments are environmentally inferior due to scattering of dust. Particularly in the cooling step, work under high heat is unavoidable, and the work is severe.

In addition, since the processing time is long and the number of steps is large,
Processing costs such as operating costs and personnel costs are high, and a huge area is required for the site.

[0006] In addition, since the steelmaking slag after the treatment contains a large amount of hydration reaction products, when sold as a roadbed material or the like, 0.5 to 0.5 to
It is necessary to leave it in a yard for a long period of about three years to reduce its inflation and stabilize it. Therefore, in the past, an invention in which high-temperature slag is sprinkled in a closed container to treat the slag has been introduced in Japanese Patent Application Laid-Open No. 55-110703. This is a method in which water is sprinkled on a high-temperature slag charged in a closed container, and hydration reaction is promoted by generated steam to stabilize the slag.

[0007]

However, the above-mentioned invention is not a means for causing a sufficient hydration reaction even if a long hydration reaction treatment time is used, and furthermore, since no crushing effect is obtained, water It is necessary to add complicated and complicated steps such as crushing after the summation reaction, and there are problems such as high equipment costs, high processing costs, and measures against dust during crushing.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has newly found a cooling treatment method capable of effectively and greatly promoting a hydration reaction utilizing a sealing treatment and at the same time obtaining a crushing effect. The characteristic feature is that high-temperature steelmaking slag is charged above a plate in a closed vessel, filled to a thickness of 0.5 to 4 m, sealed, and then filled with slag from above the slag-filled layer by 5 mm. Cooling water is sprinkled at a sprinkling density of ３０30 ton / hrm ² , and the pressure in the container and the holding time are increased by increasing the pressure in the container with the steam generated by the watering or the steam and the steam separately injected into the container. Is maintained within the range defined by the equation (1).

3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) P ≦ 15 T ≦ 1 where P: steam pressure (kg / cm ² ) T: treatment time (hr) It is also characterized by intermittent watering, stopping watering at a slag temperature of 200 ° C. or lower, and then intermittently watering while maintaining the pressure.

[0010]

According to the treatment method of the present invention, the hydration reaction is effectively and rapidly promoted, so that not only the slag stabilization is completed in a short time, but also the slag is self-crushed,
The conventional crushing process is omitted, and the process and equipment can be simplified. This self-crushing produces a synergistic effect that promotes cooling of water spray, greatly increases the cooling rate of slag, and enables short-time cooling. The above-mentioned shortening of processing time, elimination and simplification of the processing simultaneously enable labor saving, reduction of processing cost, reduction of dust measures, and easy automation of the process. Will be described in detail.

During the steelmaking slag, f. CaO is present and reacts with water or steam to cause a hydration reaction represented by the following formula.

CaO + H ₂ O = Ca (OH) _{2 It has been} conventionally said that supplying H ₂ O at a high pressure accelerates the hydration reaction. However, the hydration reaction is still slow by simply keeping the solution in high-pressure H ₂ O.
Although a certain degree of promotion can be obtained even when steam is passed and maintained at a high temperature for a long time at a slag interval as in the method of -110703, a large amount of unreacted parts is obtained, and therefore, after this treatment, it is separately vast. It was transported to a slag yard and exposed to the atmosphere, requiring long-term curing (aging).

[0013] In the present invention, water is sprayed from above the charged and filled high-temperature slag layer to spray the high-temperature slag with a watering density of 5 to 3.
When 0 ton / hrm ² is given and the inside of the container is kept at a high pressure with steam generated by itself or this steam and steam injected from another, and the slag is treated under the following conditions, FIG. 1 and FIG. As shown, self-crushing of the slag is obtained, and at the same time, the self-crushing rapidly increases the surface area of the hydration reaction start, thereby promoting the hydration reaction more rapidly than expected.

3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) P ≦ 15 T ≦ 1 where P: steam pressure (kg / cm ² ) T: treatment time (hr) Sprinkling density is 5 ton / hrm ^If it is ² or more, in a packed bed of 0.5 m or more, water is uniformly applied to the slag, and channeling (drift) becomes difficult to occur. Therefore, all the slag in the container is quenched, and at the same time, cracks due to heat shrinkage. The hydration reaction is exothermic, so the reaction is slow at high temperatures, but the reaction speed is improved by rapid cooling. In addition, f. The contact area between CaO and H ₂ O increases, and the reaction amount increases. Further, since H ₂ O is brought into contact with the slag with a liquid, it is possible to sufficiently supply H ₂ O as a reactant, thereby preventing stagnation of the reaction due to insufficient supply. Conversely, even if the water spray density exceeds 30 ton / hrm ² , the cooling rate of the slag does not change and only the function of cooling the steam in the container is performed. I will be forced. Therefore, the watering density is desirably 30 ton / hrm ² or less.

By limiting the pressure and time to the above-mentioned regions, a self-crushing phenomenon occurs, and this self-disintegration phenomenon further promotes the hydration reaction. That is, this self-crushing is carried out by f. In addition to increasing the contact area between CaO and H ₂ O to increase the hydration reaction rate, the contact area between slag and H ₂ O is increased and the slag temperature is further reduced to further increase the hydration reaction rate. Let it.

On the other hand, if the slag temperature is too low, the reaction rate will be low. Holding steam at a high pressure not only improves the reaction rate due to the high pressure, but also maintains the saturated steam temperature, which is effective in maintaining the optimum slag temperature.

In order to maintain a prescribed high pressure, when it becomes impossible to maintain the self-generated steam, steam is injected from another source to maintain the pressure. 5ton / hr from the viewpoint of pressure maintenance
It is desirable to suspend watering of m ² or more when the average slag temperature becomes 200 ° C. or less.

Next, the effect of intermittent watering will be described. When it becomes necessary to minimize the amount of water vapor injected from others, it is desirable to maintain the watering density and reduce the absolute watering amount.
For that purpose, once the surface temperature of the slag becomes 200 ° C. or less, watering is temporarily stopped. Then, a recuperation phenomenon occurs in which heat inside the slag moves to the surface, and watering is resumed at that stage.

If a method of repeating the above operation, that is, intermittent watering, is performed, the absolute watering amount is reduced, and efficient hydration reaction and self-crushing can be achieved. By the way, the intermittent interval is 1
Minutes or more is desirable. Furthermore, in the case of intermittent operation, the effect of increasing cracks due to heat shrinkage can be enjoyed to the utmost, whereby the hydration reaction region increases drastically, and the hydration reaction of the entire slag packed bed is completed quickly.

As mentioned earlier, during the pressure holding in the latter half of the treatment, if the average temperature of the slag becomes 200 ° C. or less, it is better to stop watering and hold the pressure. However, since the hydration reaction is promoted while maintaining the steam pressure, water is intermittently sprinkled to such an extent that there is no problem in maintaining the pressure.
By supplying H ₂ O as a liquid, the hydration reaction can be promoted to the maximum.

FIG. 3 shows equipment capable of processing under the conditions described above. The equipment disclosed in Japanese Patent Application Laid-Open No. 55-110703 is provided with a watering mechanism that satisfies a watering density of 5 ton / hrm ² or more, and is capable of injecting water vapor from other sources. If this facility is used, the above-mentioned slag processing is possible.

[0022]

EXAMPLE High-temperature slag having a temperature of 800 ° C., an average particle size of 100 mm and a maximum particle size of 500 mm (composition: (% CaO) =
50%, (% SiO ₂ ) = 15, (% MnO) = 12
%, (% T.Fe) = 12%, f. 5 in the form of CaO
%) Is a steel plate container 1 having a perforated plate at the bottom of the equipment shown in FIG.
Is filled with a height of 1 m, and the container is inserted into the pressure vessel of 2 with opening 3 parts. After sealing the three parts, water is injected into the pressure vessel from the water supply tank 6 through the injection nozzle 7 by using the pump 4 and the flow control valve 5. The injected water comes into contact with the high-temperature slag and turns into steam, and the pressure inside the pressure vessel is increased. The pressure is detected by a pressure gauge 8, and the pressure is adjusted by a pressure adjusting valve 9. If pressure is insufficient, steam is injected from line 10. If the steam is excessive, steam stripper 1
Dissipated from 1. The above processing was performed at the processing level shown in Table 1. The table shows the average particle size of the refined slag after the treatment. According to this table, those treated within the condition range of the present invention could be cooled to a relatively low temperature and self-crushed.
The water that had been intermittently sprayed was further self-crushed to a fine particle size necessary for the magnetic separation process for iron recovery in the subsequent process. Also, the residual cost of the hydration reaction was significantly reduced.

[0023]

[Table 1]

[0024]

By performing the slag treatment of the present invention, high-temperature slag is cooled in a short time, and self-crushing is performed in the process. After treatment, the hydration reaction of slag is greatly accelerated,
Slag stabilization is also greatly promoted.

By the above operation, the cooling step can be shortened, the crushing step can be simplified or omitted, and the magnetic separation process and the like after the crushing can be integrated with the cooling step.
Shortening, omitting, and integrating processes can also have secondary effects, such as fewer sources of dust, fewer hot workplaces, fewer personnel, lower processing costs, and easier automation. Significant promotion of slag stabilization can further reduce aging time in the yard,
The yard inventory can be reduced, and the resulting reduction of dust sources can be achieved.

[Brief description of the drawings]

Fig. 1 Relationship between watering density and slag diameter after treatment

Fig. 2 Crushing conditions depending on the pressure in the vessel and the holding time

FIG. 3 is a slag cooling treatment apparatus of the present invention.

FIG. 4A is a diagram showing a processing pattern according to the related art.
(B) is a diagram showing a processing pattern of the present invention. (C)
The figure which shows the processing pattern of this invention, and the presence of intermittent watering. (D)
FIG. 3 is a diagram showing a treatment pattern of the present invention, a watering stop pattern at a slag temperature of 200 ° C.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Container 2 ... Pressure container 3 ... Opening / closing part 4 ... Pump 5 ... Flow control valve 6 ... Water supply tank 7 ... Water injection nozzle 8 ... Pressure gauge 9 ... Pressure control valve 10 ... Steam injection line 11 ... Steam release tower

Continuing from the front page (72) Inventor Tsukasa Kashiwara Oita-shi, 1 Nishinosu, Nippon Steel Corporation Oita Works, Ltd. Inside the steelworks (72) Inventor Tetsuo Imi Oita Nishi-no-Shi 1 Oita City Nippon Steel Corporation Oita Steel Works (72) Inventor Hori Sumiki 1 Oita-shi Oaza Nishi-nosu 1 Nippon Steel Corporation Oita Steel In-house (58) Field surveyed (Int.Cl. ⁷ , DB name) F27D 15/00-15/02 C21B 3/06-3/08 C21C 7/00

Claims (3)

(57) [Claims] 1. A method for cooling a high-temperature steelmaking slag in which solidified high-temperature steelmaking slag is filled into a perforated plate in an airtight container, and water is sprayed and cooled from above the slag-filled layer. Cooling water is sprinkled at hr ² , and the pressure in the container is increased by the steam generated by the watering or the steam and the steam separately injected into the container. 3. A cooling treatment method for high-temperature steelmaking slag characterized by maintaining and treating within the range defined by the formula: 3.50 ≧ P ^0.6 × T ^0.4 ≧ 1.48 (1) P ≦ 15 T ≦ 1 : Steam pressure (kg / cm ² ) T: Processing time (hr) 2. The method for cooling a high-temperature steelmaking slag according to claim 1, wherein watering is performed intermittently. 3. The method for cooling a high-temperature steelmaking slag according to claim 1, wherein watering is stopped at a slag temperature of 200 ° C. or lower, and then intermittent watering is performed while maintaining the pressure.