JP2667799B2 - Aging method for 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 aging steelmaking slag used for roadbed materials. More specifically, the present invention relates to a method for aging a steelmaking slag used for a roadbed material. In aging that promotes the hydration reaction of steelmaking slag while maintaining it in a saturated steam atmosphere, the present invention relates to a method of determining the optimal time for the hydration reaction by grasping the state of the hydration reaction from the attenuation of the flow rate of the supplied steam. .

[0002]

2. Description of the Related Art Steelmaking slag is produced by combining components that are no longer required during melting and refining of metal. Since the slag is hard crystalline, it is cooled to a predetermined particle size after cooling. The crushed material is suitable as a roadbed material and is widely and generally used.

[0003] However, in the steelmaking slag, part of the quicklime used as a de-P / S-removing agent during the refining does not react and remains as unslagized lime (free lime). It has the property of expanding upon hydration when it reacts with water. For this reason, if the unslagized lime is used for a roadbed material in a state where it remains in the slag, a hydration reaction occurs with the passage of time, and as a result, the ground may expand, protrude, and collapse.

Therefore, conventionally, in order to use steelmaking slag as a roadbed material, aging is performed in advance to cause a hydration reaction of unslagified lime artificially to complete expansion and collapse phenomena. Was used as.

As the above aging method, the present applicant has already disclosed in Japanese Patent Application No. Hei 6-307713 the heat and excess moisture of steam in a sealable pressure vessel and by using pressurized high-temperature pressurized steam. The present invention provides a method and an apparatus for aging a steelmaking slag, which can accelerate the hydration reaction of unsmelted lime in the steelmaking slag and perform aging in a shorter time than before.

FIG. 6 shows an example of the above aging device.

A crushing device 37 for crushing the slag and a conveyor 38 for conveying the crushed slag to the charging chute 36 are arranged above. The charging chute 36 is fed so that the slag conveyed by the conveyor 38 is charged into the pressure vessel 31 via the charging chute 36.
A pressure vessel 31 is provided below the outlet of the pressure vessel. The pressure vessel 31 is a vessel that can be hermetically sealed in order to maintain the inside of the pressure vessel 31 in a saturated steam atmosphere at a set pressure and temperature, and has an upper lid 32a that can be opened and closed at an upper part and a lower lid that can be opened and closed at a lower part. It has a lid 32b. Further, a steam generator 33 is provided above the pressure vessel 31, and the steam is supplied to the pressure vessel 31.
It is connected to the pressure vessel 31 via a line 35 provided with a valve 34 to supply 31. In addition, a pipe 40 provided with a steam trap 39 is connected to a lower portion of the pressure vessel 31 for discharging the water vapor converted into hot water. A pipe 42 having a valve 41 is connected to an upper portion of the pressure vessel 31 for allowing the pressure in the pressure vessel 31 to leak after slag aging is completed. Further, in order to discharge the slag that has been aged to the outside of the pressure vessel 31, a slag vessel 43 is arranged below the pressure vessel 31. When the lower lid 32b of the pressure vessel 31 is opened, the steelmaking slag can be charged into the slag vessel 43.

[0008] An aging method using the above-described apparatus will be described below with reference to graphs of changes in temperature and pressure shown in FIG.

(1) Charging step (required time t _i ) The lower lid 32b and the valve 41 of the pressure vessel 31 are closed, the upper lid 32a of the pressure vessel 31 is opened, and the crushing device 37 adjusts the particle size to a certain level. The crushed steel slag is charged into the pressure vessel 31 from the charging chute 36 via the conveyor 38, and the upper lid 32a is closed and sealed. At this time, there is no change in the temperature and pressure inside the pressure vessel 31.

(2) Heating / Pressurizing Step (Time Required t _p ) With the valve 41 closed, the valve 34 is opened to supply the high-temperature saturated steam pressurized from the steam generator 33 to the pressure vessel 31. . The water vapor comes into contact with the inner surface of the pressure vessel 31 and the slag, takes heat from the pressure vessel 31 and the slag to be condensed, and undergoes a phase transition from the vapor phase vapor to the liquid hot water. The amount of heat accompanying this phase transition, that is, the latent heat,
And the slag is heated, and the average temperature Tc of the slag and the pressure vessel 31 rises. Since the average temperature Tc rises and the internal pressure Ps of the pressure vessel 31 also rises, the steam condensation temperature Ts also rises. The hot water generated by the phase transition increases until the internal pressure Ps of the pressure vessel 31 and the average temperature Tc with the slag rise to some extent. by the way,
When the hot water stays in the pressure vessel 31, the slag is immersed in the hot water, the transfer of latent heat is hindered, and the temperature rise rate of the slag decreases. In order to prevent this, the hot water is
The air is sequentially discharged from the lower part of the base 31 through a pipe 40 having a steam trap 39. Here, the amount of discharged hot water corresponds to the amount S of generated hot water.

(3) Insulation process (time required t _s ) Since the pressure of the pressurized high-temperature saturated steam supplied from the steam generator 33 is constant, the steam generation is performed as the internal pressure Ps of the pressure vessel 31 increases. The flow rate Q of steam supplied from the device 33 decreases, and therefore the amount S of generated hot water due to the phase transition also decreases.

Although the steam flow rate Q and the amount of generated hot water S decrease, the supply of steam is continued.
Is further increased to become a saturated steam atmosphere having a pressure substantially equal to the steam supplied from the steam generator 33. In this state, during a constant temperature, the time t _s which is determined by the method of determining the aging time, which will be described later to maintain the pressure, continued supply and discharge of hot water steam, prompting the hydration of non-slag lime. Note that the hydration reaction here is CaO +
Since H ₂ O → Ca (OH) ₂ , the steam flow rate Q supplied from the steam generator 33 further decreases as the hydration reaction proceeds.

(4) Decompression step (required time t _d ) After aging of the slag is completed, the valve 34 is closed to stop the supply of steam, the valve 41 at the top of the pressure vessel 31 is opened, and the pressure The water vapor in the container 31 is released into the atmosphere, and the pressure Ps in the container is reduced to the atmospheric pressure. At this time, the average temperature Tc of the slag and the vessel 31 and the condensation temperature Ts of the water vapor decrease.

(5) Discharge step (time required t _o ) Finally, the lower lid 32b of the pressure vessel 31 is opened, and the slag in the pressure vessel is accommodated in the slag vessel 43. As a result, the average temperature Tc of the slag and the container 31 and the condensation temperature T of the steam are
s is further reduced.

Through the above steps, aging is completed. After that, the lower lid 32b and the valve 41 of the pressure vessel 31 are closed, and the above-mentioned steps (1) to (5) are repeated, whereby the next aging can be performed.

The time required for each of the above five steps was t _i , t _p , t _s , t _d , and t _o , and the total aging time of these was t _t .

[0017]

As described above, the time required to perform aging is t _i , t _p , t _s , t
_d, and t _o are configured by, among this, (1) the time t _i required for the charging step, (2) the time t _p taken for raising the temperature-boosting process, is, as shown in FIG. 7 If the internal pressure Ps of the pressure vessel and the condensation temperature Ts of the water vapor are measured from the outside by a pressure sensor, a temperature sensor or the like, it can be grasped. Further, the times t _d and t _o required for (4) decompression process and (5) discharge process can be easily grasped based on the capacity of the pressure vessel, the amount of slag charged, and the like.

However, in the heat retaining step (3), which is the most important for accelerating the hydration reaction in the aging treatment, since the pressure and temperature in the pressure vessel are kept constant, the time required for the heat retaining step is reduced. That is, the time t _s required for the hydration reaction could not be estimated from changes in pressure, temperature, and the like.

Therefore, the required time t _s of the above-mentioned heat retaining step is:
Adjust the input amount of slag to the pressure vessel 31 to a certain range, set the input amount, quick lime (free lime) content of the slag, the appropriate water vapor pressure to the water immersion expansion ratio, to this,
The time t _s required for the heat retention process was set in consideration of safety based on experience values.

By the way, the time t _s required for the above-mentioned heat retaining step
If the slag is insufficient, the hydration reaction of the steelmaking slag cannot be completely terminated, and the grain size of the steelmaking slag cannot be adjusted uniformly, so that incompletely aged steelmaking slag will be obtained. . On the other hand, if the time used in the heat retention step is longer than necessary, the hydration reaction has been completely completed, and there is no problem with the aged product, and good roadbed material can be obtained. It causes a loss of time.

[0021] Therefore, conventionally, while there are those that produce a loss in operating time, in order to obtain completely the product completed aging, for the time t _s the minimum required hydration warmth process is completed The extra time t _s ' has been added to allow for some extra time (see FIG. 7).

The present invention has been made in view of the above situation, and an object of the present invention is to provide an aging method in which operating time is not lost.

[0023]

In the above-mentioned heat retaining step (3), while maintaining the temperature and pressure in the pressure vessel 1 constant, the hydration reaction of quicklime not yet completed has been carried out. Since high-temperature saturated steam pressurized to promote the steam is supplied, the steam flow rate Q from the steam generator 33 decreases as the hydration reaction of the quicklime contained in the slag progresses. The actual change in the heat retention process during this period is shown in FIG. FIG. 3 is an enlarged view of FIG.
The water vapor flow rate Q (ton (ton) / hour) is plotted on the Y axis, and the time t (minutes) required for the heat retention process is plotted on the X axis. The water vapor flow rate Q shows a constant decay curve with respect to the time axis. You can see that you are drawing.

Therefore, in the present invention, a change in the steam flow rate Q with respect to time t is determined before the hydration reaction is completed, focusing on the specific attenuation state of the steam flow rate Q in the above-mentioned heat retaining step. The loss of the above operation is reduced by calculating the time when it becomes 0 or the time when there is no change for a certain period of time by the arithmetic processing to determine the time required for the heat retention step. That is, in the aging method for steelmaking slag according to the first aspect of the present invention, normal-temperature steelmaking slag crushed to a certain particle size is charged into a sealable pressure vessel, and high-temperature, high-pressure saturated steam is supplied to the pressure vessel. By holding the inside of the pressure vessel at a high temperature steam atmosphere under pressure by setting the aging method to promote the hydration reaction of the steelmaking slag in the atmosphere, as the hydration reaction proceeds,
By performing arithmetic processing on a change curve in which the flow rate of pressurized high-temperature saturated steam supplied to the pressure vessel is attenuated,
The hydration reaction end point is determined to determine an optimum time for the hydration reaction.

Further, the aging method according to the second aspect of the present invention focuses on the change in the steam flow rate Q in the heat retaining step, specifically, the temporal change in the attenuation curve of the steam flow rate Q in the heat retaining step. It was done.

That is, the steam flow rate Q in the heat retaining step is:
It is expressed as Equation 1.

[0027]

(Equation 1)

When this is replaced,

[0029]

(Equation 2)

When this is integrated on both sides,

[0031]

(Equation 3)

## EQU1 ## If you transform this,

[0033]

(Equation 4)

## EQU1 ## Here, if 1 / a = A and c = B,

[0035]

(Equation 5)

Can be expressed as follows.

Further, by transforming the equation to obtain t from Equation 5,

[0038]

(Equation 6)

## EQU1 ## If you transform this,

[0040]

(Equation 7)

## EQU1 ## Here, if 1 / a = A and c = B,

[0042]

(Equation 8)

Can be expressed as

Using this t, the hydration reaction ends at the time t = t ₁ when the pressure vessel becomes a saturated steam atmosphere set by the pressurized high temperature steam supplied from the steam generator. time points t = t _2, determine the city, from these, it is possible to derive the time and require warmth step _{t s (= t 2 -t 1} ).

In other words, in the aging method for steelmaking slag according to the invention of claim 2, the steam flow rate in the invention of claim 1 is set to Q (ton (ton) / hour),
The change curve in which the steam flow rate Q is attenuated is represented by Q = exp
It is expressed by a relational expression of (At + B) + C (A, B, and C are constants), and the time when the pressure vessel becomes a steam atmosphere at a set pressure and temperature is set as a starting point (t = t ₁ ). A steam flow rate Q that changes every moment from a point is sampled for a certain period of time, a part of the change curve is determined from the sampled value, and the relational expression Q = exp (At +
B) + C, the constants of A, B, and C were determined to estimate the entire change curve, and the time point at which the hydration reaction was completed (t =
t ₂ ) (minutes) is obtained, and t ₁ is subtracted from t ₂ to obtain an optimum time for the hydration reaction.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for aging a steelmaking slag according to the present invention will be described below in more detail with reference to the drawings shown in FIGS. 1 to 4.

FIG. 1 shows an example of an aging device for steelmaking slag used in the aging method of the present invention. Above, a crushing device 7 for crushing slag, and a crushing slag into a charging chute 6. A conveyor 8 is provided for transporting the conveyor 8 to the conveyor. The pressure vessel 1 is disposed below the discharge port of the charging chute 6 so that the slag conveyed by the conveyor 8 is charged into the pressure vessel 1 via the charging chute 6. The pressure vessel 1 is a vessel that can be hermetically sealed in order to maintain the inside of the pressure vessel 1 in a saturated steam atmosphere at a set pressure and temperature, and has an upper lid 2a that can be opened and closed at the top and a lower lid that can be opened and closed at the bottom. A temperature sensor and a pressure sensor are provided outside the pressure device 1 (not shown) to have a lid 2b and to measure the pressure and temperature inside the pressure vessel 1. Further, a steam generator 3 is provided above the pressure vessel 1, and the steam is supplied to the pressure vessel.
It is connected to the pressure vessel 1 via a line 5 provided with a valve 4 for supplying to 1. Further, in order to measure the flow rate of steam supplied from the steam generator 3 to the pressure vessel 1,
The pipe 5 has a flow meter 14 closer to the pressure vessel 1 than the valve 4.
Is provided. Since the measured value of the water vapor flow rate is used for arithmetic processing, the flow meter 14 is electrically connected to an input processor and an arithmetic processing device (not shown).

Further, a pipe line 10 provided with a steam trap 9 is connected to the lower portion of the pressure vessel 1 in order to discharge the steam which has been changed to hot water. The pressure vessel
A pipe 12 having a valve 11 is connected to an upper part of the pressure vessel 1 for leaking the pressure in the pressure vessel 1 after aging of the slag is completed. In order to discharge the aged slag to the outside of the pressure vessel 1, the pressure vessel 1
A slag container 13 is provided below. When the lower lid 2b of the pressure vessel 1 is opened, the steelmaking slag is charged into the slag vessel 13.

First, the entire aging process in the aging method of the present invention using the above-described apparatus will be described below with reference to the graphs of temperature and pressure changes shown in FIG.

(1) Charging Step (Time Required t _i ) The lower lid 2b and the valve 11 of the pressure vessel 1 are closed, and the pressure vessel
After opening the upper lid 2a and crushing the steelmaking slag to a predetermined particle size by the crusher 7, the slag is charged into the pressure vessel 1 from the charging chute 6 via the conveyor 8, and the upper lid 2a
Close and seal. At this point, there is no change in the temperature and pressure inside the pressure vessel 1.

(2) Temperature rising / pressurizing step (required time t _p ) With the valve 11 closed, the valve 4 is opened to supply high-temperature saturated steam pressurized by the steam generator 3 to the pressure vessel 1. . The steam comes into contact with the inner surface of the pressure vessel 1 and the slag, takes heat from the pressure vessel 1 and the slag, condenses, and undergoes a phase transition from steam in the gas phase to hot water in the liquid phase. The amount of heat accompanying this phase transition, that is, latent heat,
Then, the slag is heated, and the average temperature Tc of the slag and the pressure vessel 1 increases. As the average temperature Tc rises and the internal pressure Ps of the pressure vessel 1 also rises, the condensation temperature Ts of steam also rises. Further, the amount of hot water generated by the phase transition increases until the internal pressure Ps of the pressure vessel 1 and the average temperature Tc with the slag rise to some extent. by the way,
When the hot water stays in the pressure vessel 1, the slag is immersed in the hot water, and the transfer of latent heat is hindered, and the temperature rise rate of the slag decreases. In order to prevent this, the hot water is
The air is sequentially discharged from the lower part of 1 through a pipe 10 provided with a steam trap 9. Here, the amount of discharged hot water corresponds to the amount S of generated hot water.

(3) Insulation process (time required t _s ) Since the pressure of the pressurized high-temperature saturated steam supplied from the steam generator 3 is constant, the steam generation is performed as the internal pressure Ps of the pressure vessel 1 increases. The flow rate Q of steam supplied from the apparatus 3 is reduced, and therefore, the amount S of generated hot water due to the phase transition is also reduced.

Although the steam flow rate Q and the amount of generated hot water S decrease, the supply of steam is continued.
The internal pressure Ps further rises to become a saturated steam atmosphere having a pressure substantially equal to the steam supplied from the steam generator 3. In this state, during a constant temperature, the time t _s which is determined by the method of determining the aging time, which will be described later to maintain the pressure, continued supply and discharge of hot water steam, prompting the hydration of non-slag lime.

Incidentally, the hydration reaction here is CaO + H ₂ O
→ Ca (OH) ₂ , as the hydration reaction proceeds,
The steam flow rate Q further decreases.

(4) Decompression step (required time t _d ) After the aging of the slag is completed, the valve 4 is closed to stop the supply of steam, the valve 11 on the upper part of the pressure vessel 1 is opened, and the pressure The water vapor in the container 1 is released into the atmosphere, and the pressure Ps in the container is reduced to the atmospheric pressure. At this time, the average temperature Tc of the slag and the container 1 and the condensation temperature Ts of the water vapor decrease.

[0056] (5) a discharge step slag (required time t _o) finally the pressure vessel by opening the lower lid 2b of the pressure vessel 1 is accommodated in the slag container 13. Thereby, the average temperature Tc of the slag and the vessel 1 and the condensation temperature Ts of the steam
Will also decrease.

Through the above steps, aging is completed. Then, by closing the lower lid 2b and the valve 11 of the pressure vessel 1 and repeating the above steps (1) to (5), the next aging can be performed again.

In the charging step (1), the steelmaking slag used as a raw material is preferably at room temperature so that it can be conveyed by a belt conveyor or the like. Even if it is slightly heated for preheating or the like, 200 It is preferable to use one having a temperature of not more than ° C. In addition, the particle size of the slag collapses during aging, but if the particle size is excessively large, it takes time for the hydration reaction of quicklime inside the particles. It is preferable to crush the particles having a particle size of 25 mm or less to 80% or more.

(2) Temperature rise. In the pressurization step, the supplied saturated steam is subjected to a hydration reaction (CaO + H ₂ O → Ca
Considering that the chemical equilibrium of (OH) ₂ ) is reversed to prevent the reaction from slaked lime to quicklime and the rate of the hydration reaction, the temperature is in the range of 130 ° C to 190 ° C, and The pressure is preferably in the range of ^{2 to} 10 kg / cm ² G.

Here, the pressure, temperature, etc. of the saturated steam supplied to the pressure vessel 1 are set within the above-mentioned ranges according to the slag input amount, the slag water immersion expansion ratio, and the free lime content of the slag. An appropriate value may be set based on the value.

Next, the arithmetic processing of the aging method of the present invention will be described with reference to FIGS. here,
Figure 4 is a schematic flowchart used as a determinant of the time t _s required for the incubating process steam flow rate Q supplied to the pressure vessel.

First, the temperature and pressure change in the pressure vessel 1 are measured by a thermometer provided in the pressure vessel 1 and the pressure gauge, and (2) the temperature raising / pressurizing process is completed and the internal pressure Ps of the vessel is increased. Is measured when a saturated steam atmosphere having a pressure substantially equal to the steam supplied from the steam generator 3 is reached, that is, when the steam flow rate Q reaches the point j, and the time is set as t = t ₁ (FIG. 2). reference).

Next, according to the flowchart shown in FIG. 4, the time t _s required for the heat retaining step is calculated through the following two procedures roughly divided.

Data Accumulation Process The steam flow rate Q supplied from the steam generator 3 to the pressure vessel 1 is the time t = t ₁ when the heat retention process is started.
Continuously over time or at regular intervals,
It is measured by a flow meter 14 provided in the.

Next, after confirming from the input signal (measured value) that the measured water vapor flow rate Q has entered the region of the attenuation curve, the input processor once causes data fluctuation due to flow meter characteristics and the like. To process. Here, as the input processing method, for example, the moving average method is preferable, and the input processing is performed by accumulating and calculating the average value while shifting the data of the electric flow rate signal in the constant axis direction in the time axis direction. is there. As other methods, a method of integrating input data and dividing by the number of input data, a method of using a least square method for each fixed sample amount accumulated by a time lag, and the like are possible.

The data of the steam flow rate Q arranged by the input processor is converted into past data Qp as shown in FIG.
(Data of past decay curves).

As a result, the steam flow rate Q is
If it is the same as p or smaller than the past data Qp, that is, if Q ≦ Qp, the warming process is continued and the arithmetic processing described later is performed.

On the other hand, if the water vapor flow rate Q is larger than the past data Qp, if Q> Qp, it is further checked whether the pressure and temperature in the pressure vessel 1 are constant. Then, similar to the case of the steam flow rate Q ≦ Qp, the arithmetic processing described later is performed. However, if there is a change in the temperature and pressure in the pressure vessel 1, it means that an appropriate state has not been secured for the heat retention process, so an alarm is issued by the alarm device to check the operating state.

A part of the decay curve of the water vapor flow rate Q is determined from the data of the water vapor flow rate Q obtained by the arithmetic processing step, and the data of Q and t at a plurality of points on this curve are expressed by the above-mentioned equation 5 or equation 8. To obtain the constants A, B, and C. Next, from the equation relating to the attenuation curve determined as a whole, the end point of the heat retention step t = t ₂
Is also calculated.

Then, the starting point t = t ₁ is subtracted from the calculated end time t = t ₂ to obtain the time t _s required for the hydration reaction.

[0071] Therefore, the time of the t _s, if caused to continue incubating process, hydration of non dregs lime contained in the slag is to complete.

The constants A, B, and C are set by sequential calculation according to the situation of the hydration reaction for each batch by the above-described calculation processing, and therefore, the above mathematical formula 5 is used. It is not necessary to consider various conditions of the slag, for example, the amount of the slag, the free lime content, the steam pressure to be supplied, the water immersion expansion ratio of the slag, etc. when determining the aging time by slag.

[0073]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the case where the above-described aging apparatus and aging method are actually used, the time required for the heat retaining step will be described below.

Example 1 A slag having 3% of free lime and a water immersion expansion ratio of 4% was charged at 50 tons, aging was performed under the condition of Ps = 4 kg / cm ² G, and the aging was performed according to the aging method of the present invention. The time required for the heat retention step was set by calculating the decay curve of the water vapor flow rate Q.

As a result, the required time was 100 minutes (t _s ), and the aging state was good.

Example 2 A slag having 5.5% free lime and a water immersion expansion ratio of 6% was subjected to 50 tons.
Then, aging was performed under the condition of Ps = 4 kg / cm ² G, and the time required for the heat retaining step was set by calculating the attenuation curve of the steam flow rate Q shown in FIG. 5 by the aging method of the present invention.

As a result, the required time was 115 minutes (t _s ), the aging state was good, and the particle size of the slag obtained by the aging was good.

Conventional Example 1 Slag having a free lime of 3% and a water immersion expansion ratio of 4% was subjected to 50 tons,
Aging was performed under the condition of Ps = 4 kg / cm ² G.
The required time is 120 minutes of watching strained warmth process safety (t _s + t
_s ') and the resulting slag was in good aging condition.

Conventional Example 2 50 tons of slag with 5.5% free lime and 6% water expansion ratio
, Ps = 4 kg / cm ² G, aging was performed. The time required for the heat insulation process with a view to safety is 150 minutes (t
_s + t _s ′), and the aging state of the resulting slag was good.

Table 1 below shows the results of the above four execution examples and the conventional example.

[0081]

[Table 1]

As can be seen from Table 1 above, when the time required for the heat retaining step was calculated using the aging method of the present invention, only the time required for the heat retaining step was found as compared with the conventional example. It was possible to shorten the time by 20 minutes and the time by Example 2 by 35 minutes. Moreover, the aging state is
Both Example 1 and Example 2 were good, and a slag with a uniform particle size could be obtained.

[0083]

According to the aging process of steelmaking slag according to the present invention, it is possible to shorten the incubating process, thus the total aging time t _t.

Further, in the calculation method according to the present invention, the constants A, B, and C are calculated from the decay curve of the water vapor flow rate Q and the relational expression between the water vapor flow rate Q and the time t _s required for the heat retention step each time aging is performed. Therefore, regardless of the amount of steelmaking slag charged into the pressure vessel 1, the content of quicklime (free lime) in the slag, the water immersion expansion ratio of the slag, etc., the hydration state of the quicklime contained in the slag is it is possible to derive the time t _s required in accordance with warmth process.

Therefore, if the minimum time t _s required for the heat retention step obtained by the present invention is used, the extra time t _s ' required for the conventional heat retention step can be omitted and the overall aging time can be shortened. , And it is possible to reduce the loss of operating time.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an aging device used in the present invention.

FIG. 2 is a diagram schematically showing a change in pressure, a change in temperature, and a change in a steam flow rate Q during aging in the present invention.

FIG. 3 is a partially enlarged view showing a steam flow rate Q in FIG. 2;

FIG. 4 is a flowchart showing a calculation method according to the present invention.

FIG. 5 is a diagram showing changes in the steam flow rate in the heat retention step in the example of the present invention.

FIG. 6 is an overall structural view of a conventional steelmaking slag aging device.

FIG. 7 is a diagram schematically showing a change in pressure, a change in temperature, and a change in water vapor flow rate Q during conventional aging.

[Explanation of symbols]

 1, 31: Pressure vessels 2a, 32a: Upper lid 2b, 32b: Lower lid 3, 33: Steam generator 4, 34: Valve 5, 35: Pipe line 6, 36: Charging chute 7, 37: Crusher 8, 38 ... Conveyor 9,39 ... Steam trap 10,40 ... Pipeline 11,41 ... Valve 12,42 ... Pipeline 13,43 ... Slag container 14 ... Flowmeter

Continuation of the front page (72) Inventor Yosuke Suezawa 3-1-1, Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. Kobe Plant (72) Inventor Kazunari Teramae 3-chome, Higashikawasaki-cho, Chuo-ku, Kobe, Hyogo Prefecture No. 1 No. 1 Kawasaki Heavy Industries, Ltd. Kobe factory (56) Reference JP-A-8-165151 (JP, A) JP-A-8-259283 (JP, A)

Claims (2)

(57) [Claims] 1. A normal-temperature steelmaking slag crushed to a certain particle size is charged into a sealable pressure vessel, and high-pressure, high-pressure saturated steam is supplied to the pressure vessel to set the inside of the pressure vessel to a predetermined pressure. An aging method in which the hydration reaction of steelmaking slag is promoted in the atmosphere while maintaining the slag in a heated high-temperature steam atmosphere. As the hydration reaction proceeds, pressurized high-temperature saturated steam supplied to the pressure vessel. A method for aging a steelmaking slag, characterized in that the hydration reaction end time is obtained by arithmetically processing a change curve in which the flow rate decays to obtain an optimum time for the hydration reaction. 2. The steam flow rate is set to Q, and a change curve in which the steam flow rate Q is attenuated is represented by Q = exp (At +
B) + C, where A, B, and C are constants,
The time point when the pressure vessel becomes a steam atmosphere at a set pressure and temperature is set as a starting point (t = t ₁ ), and the steam flow rate Q which changes momentarily from the starting point is sampled for a certain period of time.
A part of the change curve is determined from the sampled value, and this is determined by the relational expression Q = exp (At + B) + C of the change curve.
Applying this, the constants of A, B, and C are obtained, the overall change curve is estimated, the time point (t = t ₂ ) at which the hydration reaction ends is obtained, and t ₁ is subtracted from this t ₂ to obtain the above The aging method for steelmaking slag according to claim 1, wherein an optimal time for the hydration reaction is obtained.