JP2003335558A - Method for treating blast furnace granulated slag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating a blast furnace granulated slag that is capable of exhibiting a sufficient hydration reaction inhibition effect and a consolidation inhibition effect. <P>SOLUTION: The method comprises steps of dispersing the blast furnace granulated slag and bringing the blast furnace granulated slag in a dispersed state contact with a substance containing at least either one of a carbon dioxide gas or an aqueous carbonic acid solution to treat the blast furnace granulated slag. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for treating granulated blast furnace slag.

[0002]

2. Description of the Related Art Granulated blast furnace slag is a blast furnace slag produced as a by-product in the ironmaking process, which is rapidly cooled and granulated by injecting pressurized water, and is produced over 20 million tons per year. Since granulated blast furnace slag has hydraulic properties, it has been pulverized and used as a raw material for cement. In addition, as natural sand is being depleted in recent years, from the perspective of resource conservation, as a substitute for natural sand, as a material for civil engineering work and fine aggregate for concrete,
Opportunities are increasing for using granulated blast furnace slag itself or as a particle size adjustment product by crushing and adjusting the particle size.

By the way, granulated blast furnace slag, whether used as it is or as a particle size preparation, is often stored for a long time in an open state or in a storage tank because it is waiting for shipping or waiting for use. It may be transported over a long period of time by a ship or the like. The hydraulic property of granulated blast furnace slag is an essential property when used as a cement raw material, but if a hydration reaction already occurs during long-term storage or transportation before use, it will be used as a raw material for cement. Performance deteriorates and concrete with sufficient strength cannot be obtained. Furthermore, when the slag particles solidify the hydration product strongly in the medium and become agglomerates, they can no longer be used as fine aggregates, and since their bond strength is high, they are crushed and sized into the original particles. Is extremely labor intensive.

Further, when granulated blast furnace slag is used as a material for civil engineering work, its hydraulic property is advantageous for the purpose of forming a strong ground, but it is used as a sand mat material for the surface treatment method of soft ground. In this case, depending on the number of days elapsed, it solidifies during construction, and it is extremely difficult to drive and penetrate a vertical drain material such as a paper drain or a plastic drain next to this sand mat material. For civil engineering applications, it is sometimes used as embankment material, backfill material, backfill material, etc.In this case as well, after the construction, several days to several years later, that part is dug up and a new buried object is newly created. There are also cases in which it is buried, replanted, and dug again after several decades. In these cases, the solidification of granulated slag is
The excavation work requires a large amount of power, and there is also a risk of damaging existing buried objects during piping work. Therefore, conventionally, the use of granulated blast furnace slag for this type of application has been restricted.

The hydration reaction and the solidification phenomenon are particularly remarkable in the summer when the temperature is high, and it is considered that they proceed by the following mechanism. First, the hydration reaction of granulated blast furnace slag is
It begins with the elution of calcium from the glass and the rise in pH, and the components such as silicon and aluminum elute due to this alkaline stimulation. When the concentrations of the components such as calcium, silicon, and aluminum in the liquid phase near the granulated blast furnace slag particles rise to the precipitation conditions of various hydrated products due to the eluted components, hydrate formation begins and ettringite (3
CaO ・ Al ₂ O ₃ / 3CaSO ₄・ 32H ₂ O),
A hydrate such as calcium silicate hydrate (C-S-H) is generated, the layer thickness is gradually increased, and the particles are solidified. Also,
This hydrate formation reaction occurs not only in the liquid phase but also inside the particles near the surface of the granulated blast furnace slag.

Several methods have been proposed in the past to prevent hydration and caking of granulated blast furnace slag or its particle size preparation. For example, Japanese Patent Publication Sho-58-359
JP-A-44 discloses an anti-caking agent containing an aliphatic oxycarboxylic acid, an aliphatic oxycarboxylic acid salt or a mixture of two or more kinds thereof as important components. In addition, JP-A-54
Japanese Patent Publication No. 71793/1990 discloses a method for preventing solidification by spraying an aqueous acid solution on granulated blast furnace slag to once neutralize active calcium.

Further, carbon dioxide is brought into contact with CaO contained in the granulated blast furnace slag, or CaO contained in the granulated blast furnace slag.
Carbon dioxide (H ₂ C) contained in water bubbled with carbon dioxide
O ₃ ), etc. are brought into contact with the surface of the slag particles to make them insoluble in CaC.
A method of forming a film of O ₃ and suppressing the elution reaction of calcium or the like from the granulated blast furnace slag by this film and suppressing the hydration reaction and thus the solidification is disclosed.

[0008] Specifically, JP-A-54-112304, JP-A-54-127895, JP-A-54-
No. 131504 and Japanese Patent Laid-Open No. 55-162454 disclose a method of bringing carbon dioxide gas in a gas phase into contact with granulated blast furnace slag or lightly crushed granulated blast furnace slag.

Further, Japanese Unexamined Patent Publication No. 10-95644 discloses a method for preventing solidification by immersing granulated blast furnace slag in a carbonic acid solution in which carbon dioxide gas is dissolved.

However, among these conventional techniques, the method using an anti-caking agent in Japanese Patent Publication No. 58-35944 discloses:
If it rains during the open-packed state, the anti-caking agent will elute from the surface of the granulated blast furnace slag, so that it will not exhibit a sufficient anti-caking function. Further, when used as a material for civil engineering work under the condition of being immersed in water or seawater, similarly, since the anti-caking agent flows out into water or sea water, the caking cannot be sufficiently prevented.

Further, in the method of spraying an aqueous acid solution disclosed in JP-A-54-71793, when used as a cement raw material or a concrete aggregate, residual acid ions have an adverse effect on the properties of concrete, so the addition amount is sufficient. Have to manage.

Further, in the case of the method of contacting the granulated blast furnace slag with carbon dioxide gas in the vapor phase state as in Japanese Patent Laid-Open No. 54-112304, carbon dioxide gas is added to the granular granulated slag filled in the hopper or in the open pile. It is difficult to evenly disperse the water, and in a portion where the gas does not spread, it may not be possible to obtain a sufficient hydration reaction suppressing effect and solidification suppressing effect.

On the other hand, in the case of the method of dipping cooled granulated blast furnace slag in an aqueous solution of carbonic acid as disclosed in JP-A-10-95644, macroscopically, carbonic acid can be uniformly supplied to the granulated blast furnace slag. However, when the granulated blast furnace slag is agglomerated, the carbonic acid aqueous solution may not be supplied to all the packed granulated blast furnace slag particles microscopically. In this case as well, it may not be possible to obtain a sufficient hydration reaction suppressing effect and solidification suppressing effect in a place where the aqueous carbonate solution is not spread.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a method for treating granulated blast furnace slag capable of exerting sufficient hydration reaction preventing effect and solidification preventing effect. The purpose is to provide.

[0015]

In order to solve the above problems, according to a first aspect of the present invention, a step of dispersing granulated blast furnace slag, and a carbon dioxide gas and an aqueous carbonate solution in the dispersed granulated blast furnace slag. And a step of bringing a substance containing at least one of the above into contact with the granulated blast furnace slag. In this case, the step of dispersing the granulated blast furnace slag particles may be performed at any one of mixing, stirring, sieving and conveying the granulated blast furnace slag.

According to a second aspect of the present invention, when dewatering the granulated blast furnace slag with a drum rotary dehydrator in the granulated blast furnace slag manufacturing process, the granulated blast furnace slag is supplied with carbon dioxide gas and an aqueous carbonate solution. Provided is a method for treating granulated blast furnace slag, which comprises contacting a substance containing at least one of them.

According to a third aspect of the present invention, when the granulated blast furnace slag is conveyed to or dropped from the belt conveyor, the granulated blast furnace slag is contacted with a substance containing at least one of carbon dioxide gas and an aqueous carbonate solution. Disclosed is a method for treating granulated blast furnace slag.

According to a fourth aspect of the present invention, when sieving the granulated blast furnace slag, carbon dioxide gas and an aqueous carbonate solution are added to the granulated blast furnace slag on the screen or the granulated blast furnace slag falling below the sieve. Provided is a method for treating granulated blast furnace slag, which comprises contacting a substance containing at least one of them.

In a state where the granulated blast furnace slag is filled in a container or piled up, even if a substance containing at least one of carbon dioxide gas and a carbonic acid aqueous solution is supplied, due to the presence of agglomerated portions, etc., the granulated blast furnace slag inside The substance containing at least one of carbon dioxide gas and carbonic acid aqueous solution may not reach the particles sufficiently. It is easy to uniformly spread over the whole, carbonate ions are supplied to the individual granulated blast furnace slag particles, and a calcium carbonate film can be uniformly formed on the surface of each granulated blast furnace slag particle. Therefore, a sufficient effect of suppressing the hydration reaction and an effect of preventing caking can be obtained.

From the second viewpoint to the fourth viewpoint, it is a specific application in the production facility of granulated blast furnace slag. In the drum rotary dehydrator of the second viewpoint, the rotation of the drum causes granulation of the blast furnace granules therein. The slag is in a dispersed state, and when the blast furnace granulated slag is conveyed to or from the belt conveyor during transportation of the blast furnace granulated slag according to the third aspect, the blast furnace granulated slag particles are dispersed and dispersed in the fourth state. The granulated blast furnace slag on the screen or the granulated blast furnace slag falling below the screen is also in a dispersed state, and in that state, a substance containing at least one of carbon dioxide gas and an aqueous carbonate solution is supplied. By this, carbonate ions are uniformly supplied to the entire granulated blast furnace slag, and a calcium carbonate film can be uniformly formed on the surface of all granulated blast furnace slag particles, and sufficient water content can be obtained. The reaction inhibiting effect and anti-caking effect can be obtained.

In any of the above aspects, it is preferable to set the temperature of the granulated blast furnace slag to which the substance containing at least one of the carbon dioxide gas and the carbonic acid aqueous solution is contacted, to 20 ° C. or higher. As the granulated blast furnace slag, the granulated blast furnace slag generated in the pig iron manufacturing process can be used as it is, or can be used as a particle size-adjusted product with the particle size adjusted, or can be used as a mixture thereof.

In the present invention, the substance containing at least one of carbon dioxide gas and carbonic acid aqueous solution may be only carbon dioxide gas or only carbonic acid aqueous solution, and may contain other substances. A mixture of both may be used. Therefore, droplets of fine carbonic acid aqueous solution (spray droplets) formed by supplying gas such as air to the carbonated aqueous solution or droplets of fine carbonic acid aqueous solution formed by supplying carbon dioxide gas to the aqueous carbonate solution (spraying liquid). Drops) are naturally included in the above substances.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The present invention has a step of dispersing the granulated blast furnace slag and a step of supplying a substance containing at least one of carbon dioxide gas and an aqueous solution of carbonic acid to the dispersed granulated blast furnace slag.

The method of dispersing the granulated blast furnace slag is not limited in its technique, and preferably, the granulated blast furnace slag is dispersed in a substantially particulate form. Although special equipment for dispersing the granulated blast furnace slag may be provided, it is preferable to use a process capable of dispersing the granulated blast furnace slag in the existing equipment such as the granulated blast furnace slag manufacturing equipment. For example, when the granulated blast furnace slag is mixed, stirred, sieved, and conveyed, the granulated blast furnace slag can be brought into a dispersed state, and thus any of these steps can be performed as a dispersion step. Among these, in order to disperse the granulated blast furnace slag during transportation, it is possible to use, for example, the case of dropping the granulated blast furnace slag at the time of transferring to a conveyor.

The method of contacting the dispersed blast furnace granulated slag with the substance containing at least one of carbon dioxide gas and carbonic acid aqueous solution is not particularly limited, and various methods can be adopted. For example, as shown in FIG. 1 (a), carbon dioxide gas or a gas containing carbon dioxide gas is sprayed from a nozzle 2 to the granulated blast furnace slag 1 in a state of being dispersed in particles by an appropriate means, or an aqueous solution of carbonic acid is sprayed. Carbon dioxide or other gas such as air may be sprayed to bring them into contact with the granulated blast furnace slag 1, or as shown in FIG.
The carbonic acid aqueous solution is sprayed from a nozzle 3 provided above the dispersed blast furnace water granulated slag 1 or, as shown in (c) of FIG. Examples of the method include stirring the crushed slag 1 in a dipped state to bring the granulated blast furnace slag 1 into a dispersed state.

In the state where the granulated blast furnace slag is dispersed as described above, the substance containing at least one of carbon dioxide gas and carbonic acid aqueous solution is brought into contact with the above-mentioned form,
Carbon dioxide gas and carbonic acid aqueous solution are easy to spread evenly throughout,
Carbonate ions are supplied to each granulated blast furnace slag particle, and a calcium carbonate film can be formed uniformly on the surface of each granulated blast furnace slag particle, and a sufficient hydration reaction suppressing effect and solidification preventing effect are obtained. be able to.

The granulated blast furnace slag may be directly treated, but the granulated blast furnace granulated slag may be treated.

In the present invention, either carbon dioxide gas or an aqueous solution of carbonic acid is used as described above, but the aqueous solution of carbonic acid can be easily produced by dissolving carbon dioxide gas in water as follows.

Carbon dioxide is easily dissolved in water and its solubility is
CO_TwoProportional to concentration and gas pressure. C at 25 ° C atmospheric pressure
O_TwoThe saturated solubility of 100% gas is 0.037 normal (0.
16 g / 100 g water). Dissolution of carbon dioxide is the following formula
As shown in (1), the form after dissolution is carbonic acid (H_TwoC
O_Three), Bicarbonate ion (HCO_Three ⁻), Carbonate ion
(CO_Three ^2-), Carbonic acid in the acidic region, charcoal in the neutral region
Oxygen ion, carbonate ion is stable in the alkaline region
Yes, each abundance ratio changes depending on pH.   CO_Two+ H_TwoO → H_TwoCO_Three→ H⁺+ HCO_Three ⁻→ 2H⁺+ CO_Three ^2-                                                           …… (1)

FIG. 2 is a schematic sectional view showing an example of a facility for producing a carbonated aqueous solution. This manufacturing facility includes a tower 11 capable of storing water therein, a water supply mechanism 12 for supplying water from a lower portion of the tower 11, a gas disperser 13 for blowing carbon dioxide gas into the water in the tower 11, and a gas disperser. A carbon dioxide gas supply mechanism 14 for supplying carbon dioxide gas to 13, a water intake pipe 15 for taking out an aqueous carbonate solution from the upper part of the tower 11, a duct 16 provided so as to cover the upper part of the tower 11, and exhaust from the duct 16. The exhaust part 17 for exhausting the exhaust gas from the exhaust part 17
3 has an introduction pipe 18 that leads to the gas inlet side.

When the aqueous carbonate solution is produced by this production facility, water is continuously supplied from the water supply mechanism 12 into the tower 11, or a predetermined amount of water is supplied from the water supply mechanism 12 into the tower 11. After the water supply mechanism 12 is stopped after supplying, carbon dioxide gas or a gas containing carbon dioxide gas supplied from the carbon dioxide gas supply mechanism 14 is continuously blown into the water in the tower 11 from the gas disperser 13 to generate bubbles. Dispersed as a group, tower 11
Carbon dioxide is absorbed by the water in the solution to form a carbonated aqueous solution. In this case, if the carbon dioxide gas supply mechanism 14 supplies the pressurized gas, the pressurized gas can be dissolved in the water in the tower 11. The obtained carbonated aqueous solution is taken out from the water intake pipe 15 and supplied to the granulated blast furnace slag. In addition, the excess carbon dioxide gas blown from the gas disperser 13 is removed by the duct 1
6 is exhausted through the exhaust unit 17. At this time, the exhausted gas can be directly discharged to the outside of the system, but can also be circulated and reused in the gas disperser 13 via the introduction pipe 18. It is also possible to use exhaust gas as the gas containing carbon dioxide gas blown from the gas disperser 13, and by combining this with the reuse of exhaust gas from the upper part of the tower 11, a carbonated aqueous solution can be produced extremely inexpensively. can do.

Instead of blowing carbon dioxide gas or a gas containing carbon dioxide gas into water as described above, carbon dioxide gas or a gas containing carbon dioxide gas may be supplied into the container and water may be sprayed into the container. Carbonated water can be produced. Also in this case, carbon dioxide gas or a gas containing carbon dioxide gas can be dissolved in water under pressure.

Next, a specific example in which the present invention is carried out in a granulated blast furnace slag manufacturing facility or a granulated blast furnace granulated slag manufacturing facility will be described. In the production of granulated blast furnace slag, when water is supplied to the slag discharged from the blast furnace and granulated, the granulated blast furnace slag becomes a slurry, and this granulated slag slurry is dehydrated with an invar filter that is a drum rotary dehydrator. However, since the granulated blast furnace slag is in a dispersed state at this time, the present invention is carried out by bringing the granulated blast furnace slag into contact with a substance containing at least one of carbon dioxide gas and an aqueous carbonate solution in the invar filter. be able to.

A detailed description will be given below. 3A and 3B are views showing the structure of the invar filter, FIG. 3A is a side sectional view, and FIG. 3B is a sectional view taken along the line AA in FIG. The invar filter 20 has a rotary drum 21 rotatable by a motor (not shown), and an outer peripheral portion of the rotary drum 21 is composed of a double wire net 22 for filtration and reinforcement.
Inside the wire net 22, a large number of vanes (raising wire nets) 23 are attached along the circumference. Rotating drum 2
A distributor 25 is inserted along the longitudinal direction of the rotary drum 21 from the introduction portion 24 into the inside of the unit 1. Below the distributor 25 is a cushion box 2
6 is provided, and the slurry distributed by the distributor 25 is uniformly supplied to the vanes 23 of the rotating rotary drum 21 via the cushion box 26. Above the distributor 25, the discharge conveyor 2
7 is provided horizontally along the longitudinal direction of the rotary drum 21, and above the discharge conveyor 27, a deflector (guide plate) 28 for guiding the scraped and dehydrated blast furnace granulated slag to the discharge conveyor. It is provided. The deflector 28 is supported by a support beam 29. Further, a carbon dioxide gas supply pipe 31 which is annularly arranged horizontally above the discharge conveyor 27 is provided.
Is provided, and a plurality of nozzles 32 are provided above the carbon dioxide supply pipe 31. Then, carbon dioxide gas is supplied from the nozzle 32 to the granulated blast furnace slag 33 which is being dropped from the vane 23 located above to the discharge conveyor 27.

The invar filter 20 configured in this way
In the above, while rotating the rotating drum 21, the granulated blast furnace slag slurry passes through the distributor 25 and the cushion box 26 and is rotating.
One vane 23 is uniformly supplied. The supplied slurry is scraped up by the vanes 23, and the water content therein is discharged through the wire net 22 and dehydrated. The dewatered blast furnace granulated slag 33 drops near the top, and the falling blast furnace granulated slag 33 is guided by the deflector 28 and placed on the discharge conveyor 27, and discharged from the invar filter 20.

At this time, since the granulated blast furnace slag in the middle of falling is in a dispersed state, carbon dioxide gas is supplied to the granulated blast furnace slag in a dispersed state from a plurality of nozzles 32 provided above the discharge conveyor 27. , Carbon dioxide is spread all over the granulated blast furnace slag, is dissolved in the water around the individual granulated blast furnace slag particles, and carbonate ions are supplied, forming a uniform calcium carbonate film on the surface of each granulated blast furnace slag particle. It is possible to obtain a sufficient effect of suppressing the hydration reaction and an effect of preventing caking.

Further, the granulated blast furnace slag discharged from the inva filter by the discharge conveyor 27 is supplied to the product tank through several conveyors. Since the granulated blast furnace slag is in a dispersed state when the granulated blast furnace slag falls from the conveyor to the product tank, the granulated blast furnace slag may be contacted with a substance containing at least one of carbon dioxide gas and an aqueous carbonate solution. For example, as shown in FIG. 4, when the granulated blast furnace slag 43 is dropped from the conveyor 41 to the conveyor 42, the granulated blast furnace slag 43 is in a dispersed state. For example, if the carbonic acid aqueous solution is brought into contact with the granulated blast furnace slag by spraying the carbonic acid aqueous solution, the carbonic acid aqueous solution spreads throughout the granulated blast furnace slag, and carbonate ions are supplied to the individual granulated blast furnace slag particles. A calcium carbonate film can be uniformly formed on the surface of the crushed slag particles, and a sufficient hydration reaction suppressing effect and solidification preventing effect can be obtained.

A facility for producing a particle size-adjusted product such as blast-furnace slag fine aggregate from granulated blast-furnace slag is provided with a vibrating screen for sieving crushed blast-furnace slag crushed slag. Since the blast furnace granulated slag crushed material above and the blast furnace granulated slag crushed material that is falling through the vibrating sieve are both in a dispersed state, at least carbon dioxide gas and an aqueous carbonate solution are added to this blast furnace granulated slag crushed material. You may make it contact the substance containing one. For example, as shown in FIG.
A vibrating sieve 52 is provided below the conveyor 51, and the vibrating sieve 5
A carbon dioxide gas supply pipe 54 having a plurality of nozzles 55 is provided above 2, and carbon dioxide gas can be sprayed from the nozzles 55 to the blast furnace granulated slag crushed material 58 dropped from the conveyor 51 to the sieve mesh 53. . Further, for example, carbon dioxide gas can be sprayed from the nozzle 57 while the granulated blast furnace slag crushed material 59 that has passed through the sieve mesh 53 is falling onto the conveyor 56. The crushed granulated blast furnace slag that has not passed through the sieve mesh 53 is discharged from the discharge port 52a provided on the side wall of the vibrating sieve 52 and returned to the crushing device. Also,
The blast furnace granulated slag crushed material 59 that has passed through the sieve mesh 53 is conveyed as a product to the product tank by the conveyor 56.

In this case, the crushed granulated blast furnace slag 58 on the sieve mesh 53 and the crushed granulated blast furnace slag 59 which has dropped after passing through the sieve mesh 53 are both in a dispersed state. By contacting carbon dioxide gas as described above, carbon dioxide gas is spread over the entire granulated blast furnace slag,
Carbon dioxide gas is supplied to each granulated blast furnace slag particle, and a calcium carbonate film can be formed uniformly on the surface of each granulated blast furnace slag particle, and a sufficient hydration reaction suppressing effect and anti-caking effect are obtained. be able to. The carbon dioxide gas may be sprayed from the nozzle 55 and the nozzle 57, or both may be sprayed.

In the above specific examples, an example of spraying carbon dioxide gas has been shown, but it goes without saying that the carbonic acid aqueous solution is sprayed, the carbonic acid aqueous solution is sprayed with a gas such as carbonic acid gas, and the carbonic acid aqueous solution is dipped in the carbonic acid aqueous solution. Any of the above-described embodiments in which a substance containing at least one of carbon dioxide gas and a carbonic acid aqueous solution is brought into contact with each other may be adopted.

In the present invention, from the viewpoint of reactivity, it is preferable that the temperature of the granulated blast furnace slag contacted with a substance containing at least one of carbon dioxide gas and an aqueous carbonate solution is 20 ° C. or higher. In the summer, even if the granulated blast furnace slag in contact with the substance containing at least one of carbon dioxide gas and carbonic acid aqueous solution is left as it is, the temperature of 20 ° C or higher can be secured.
Since it is difficult to secure the temperature of 20 ° C. or higher in the winter season, it is preferable to heat the granulated blast furnace slag in contact with the substance containing at least one of carbon dioxide gas and an aqueous carbonate solution by an appropriate heating means. The granulated blast furnace slag immediately after production has a temperature of 60 ° C. or higher, which is preferable from the viewpoint of reactivity. Since the carbonation reaction proceeds at higher temperatures and the solubility of carbonate ions decreases at higher temperatures, the higher the temperature of the mixture of the aqueous carbonate solution and the granulated blast furnace slag, the greater the effect of supplying carbon dioxide gas. However, at 90 ° C., the solubility of carbonate ions is significantly reduced,
In fact, the upper limit is about 80 ° C.

[0042]

EXAMPLES Examples of the present invention will be described below. (Example 1) In the step of supplying the granulated blast furnace slag slurry to the invar filter shown in FIG. 3 at a supply rate of 150 t / h in dry conversion for dehydration, supplying carbon dioxide gas with a concentration of 20% at 500 Nm ³ / h. Carbon dioxide was supplied to the blast furnace granulated slag by supplying it into the invar filter at a speed. The temperature of the granulated blast furnace slag at that time was 60 ° C.

(Embodiment 2) In the step of supplying the granulated blast furnace slag crushed product at a supply rate of 150 t / h to the vibrating screen for sieving the crushed blast furnace slag shown in FIG. No. 5 of No. 5) and the nozzle under the sieve (Nozzle 57 of FIG. 5) are combined to give a total of 500% of carbon dioxide having a concentration of 20%
Carbon dioxide was brought into contact with the crushed blast furnace granulated slag in a dispersed state on the sieve and the crushed blast furnace granulated slag in a dispersed state below the sieve by supplying at a supply rate of Nm ³ / h. The temperature of the crushed granulated blast furnace slag at that time was 60 ° C.

(Comparative Examples 1, 2 and 3) Completely untreated granulated blast furnace slag was designated as Comparative Example 1, 100 m ^{3 of} carbonated aqueous solution and 100 t of granulated blast furnace slag were charged, and the granulated blast furnace slag was converted into carbonated aqueous solution. Comparative Example 2 in which the temperature was 18 ° C.
When charging 100 tons of granulated blast furnace slag at a supply rate of 150 t / h to the blast furnace granulated slag storage tank, carbon dioxide gas is supplied to the blast furnace granulated slag storage tank at a supply rate of 500 Nm ³ / h, Comparative Example 3 was one in which the temperature of the crushed slag was 60 ° C.

The examples 1 and 2 and the comparative examples 2 and 3 which have been treated as described above and the untreated comparative example 1 have an inner diameter of 100 mm,
Fill a container with a height of 127 mm (internal volume 1 liter),
The whole container was immersed in a constant temperature water bath at 80 ° C., and the solidified state after curing for a predetermined period was observed (indoor scale evaluation). Further, about 100 tons of each treated slag was charged into a groove having a depth of 1.5 m, a width of 4 m, and a length of 10 m in one section, and water was poured to observe the solidified state (implementation scale evaluation). The results are shown in Table 1.

[0046]

[Table 1]

As shown in Table 1, the untreated slag of Comparative Example 1 began to solidify within 1 month by the room scale evaluation at 80 ° C. and within 3 months by the room temperature implementation scale evaluation. 18 ° C
In Comparative Example 2 immersed in the aqueous solution of carbonic acid under the conditions of No. 3, solidification started within 2 to 3 months on the indoor scale, and from 6 months to 1 year on the practical scale. In Comparative Example 3 in which carbon dioxide gas was blown under the condition of 60 ° C., solidification started within 2 months to 3 months on the indoor scale, and solidification started within 6 months to 1 year on the practical scale. On the other hand, Example 1 in which carbon dioxide gas was blown into the Inva filter and Example 2 in which carbon dioxide gas was supplied above and below the sieve under the condition of 60 ° C. were indoors for 6 months, and for implementation scale for 2 years. Did not solidify.

[0048]

As described above, according to the present invention,
It is possible to provide a method for treating granulated blast furnace slag capable of exhibiting a sufficient hydration reaction preventing effect and a caking preventing effect.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an implementation state of a method of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of a carbonic acid aqueous solution production facility.

FIG. 3 is a cross-sectional view showing an invar filter (drum rotary dehydrator) in which the present invention is implemented.

FIG. 4 is a diagram for explaining a state in which the present invention is carried out at a connecting portion of a conveyor that conveys granulated blast furnace slag.

FIG. 5 is a view for explaining a state in which the present invention is carried out in a vibrating screen for screening granulated blast furnace slag.

[Explanation of symbols]

1; Granulated blast furnace slag 2, 3; nozzle 4; tank 20: Invar filter (drum rotary dehydrator) 21; rotating drum 22; wire mesh 23; Vane 25; Distributor 26; Cushion box 27; Discharge conveyor 28; Deflector 31; Carbon dioxide gas supply pipe 32; nozzle 41, 42; conveyor 43; Granulated blast furnace slag 44; Nozzle 52; Vibrating screen 53; sieve mesh 55, 57; nozzle 58, 59; Granulated blast furnace slag

Claims (7)

[Claims] 1. A blast furnace water comprising: a step of dispersing granulated blast furnace slag; and a step of contacting the dispersed granulated blast furnace slag with a substance containing at least one of carbon dioxide gas and a carbonated aqueous solution. Processing method of crushed slag. 2. The step of dispersing the granulated blast furnace slag is performed at any one of mixing, stirring, sieving and conveying the granulated blast furnace slag. Method for processing granulated blast furnace slag. 3. A substance containing at least one of carbon dioxide gas and an aqueous carbonate solution is brought into contact with the granulated blast furnace slag during the dehydration treatment of the granulated blast furnace slag by the drum rotary dehydrator in the granulated blast furnace slag manufacturing process. A method for treating granulated blast furnace slag, which comprises: 4. A blast furnace, wherein a substance containing at least one of carbon dioxide gas and a carbonated aqueous solution is brought into contact with the granulated blast furnace slag when the granulated blast furnace slag is conveyed to or dropped from a belt conveyor. Granulated slag treatment method. 5. When sieving granulated blast furnace slag, a substance containing at least one of carbon dioxide gas and an aqueous carbonate solution is brought into contact with the granulated blast furnace slag on the screen or the granulated blast furnace slag falling below the screen. A method for treating granulated blast furnace slag, which comprises: 6. The temperature of granulated blast furnace slag contacted with the substance containing at least one of carbon dioxide gas and carbonic acid aqueous solution is set to 20 ° C. or higher, and any one of claims 1 to 5 is provided. The method for treating granulated blast furnace slag according to. 7. The granulated blast furnace slag is used as a granulated product in which the granulated blast furnace slag generated in the ironmaking process is used as it is and / or the particle size thereof is adjusted. The method for treating granulated blast furnace slag according to any one of 1.