JP2002265246A - Slag granulated material and its production equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slag granulated material which has high crushing strength and is capable of appropriately being used as a substitute for sand. SOLUTION: The production process of this slag granulated material comprises preparing slag cake consisting of powdery slag in a dry state, fly ash and cement, (stage a1), charging the prepared slag cake into an agitation granulator 36 and breaking and grinding the charged slag cake, (stage a2), after the grinding, adding the prepared fly ash and cement to the ground slag cake and mixing them together in a dry state, (stages a3 and a4), after the mixing, while adding water to the resulting powdery mixture, granulating the powdery mixture into spherical granulated particles (granules), (stage a5), and after the granulation, allowing the granules to stand still to cure the granules, (state a6), wherein, since the mixing of the raw materials is performed in a dry state, the raw materials can uniformly be mixed, and in the curing of the granules, the hydration reaction is promoted, and further, since the powdery slag, fly ash used as a silica source, and cement are used as the raw materials by the curing after the granulation, a hydration-hardened material each of the granules of which has integrity, can be formed. Thus, crushing strength of the objective slag granulated material can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a granulated slag containing steelmaking slag suitably used for concrete aggregate and the like, and a facility for producing the same.

[0002]

2. Description of the Related Art Conventionally, slag generated in a steelmaking plant is separated from metal by grinding, beneficiation and classification.
It is separated into granular slag and fine powder slag.
Among these, the metal component is used again as a raw material for steelmaking, and the granular slag is effectively used for roadbed materials and the like. On the other hand, fine powdery slag is recovered as a cake-like solid from a sedimentation tank during wet processing, and most of the slag is disposed of as industrial waste without being effectively used.

[0003] Japanese Patent Application Laid-Open No. 7-237949 discloses a prior art in which a cake-like solid (hereinafter, referred to as a cake) composed of such fine particles is treated and used effectively.
According to this prior art, sludge cake and cement generated during crushed stone production are kneaded through a two-stage kneader, and the kneaded material is forcibly pushed into a mold on the surface of a briquetting roll, compressed and granulated. Then, a method of converting the crushed stone sludge into an aggregate for curing is described. In this prior art,
The sludge cake is merely mechanically dewatered by a filter press or the like, and the sludge cake is not dried. Also, it is difficult to shape the shape into a sphere, and the entire shape is formed into a polyhedron such as an octahedron. In this prior art, the strength of the granulated material is low, and high strength is required, as described in the effect of the invention that the crushed stone sludge can be used as a concrete material of a low-strength part by converting it into aggregate. There is a problem that it cannot be applied to applications.

Further, as another prior art, a turbid water cake generated in a turbid water treatment process of a crushed stone plant and cement as a solidifying material are charged into a mixing granulator, and the turbid water cake and cement are mixed and granulated to form a sandy mixture. A method for producing a granulated product has been proposed. In this method, the drying step of the turbid water cake is omitted, and the turbid water cake is mixed and granulated in a water-containing state. High strength products are produced by hydrothermal treatment in an autoclave. This prior art has a problem that a large amount of a solidifying material such as cement is required, and the running cost is high. Further, when the hydrothermal treatment is not performed, there is a problem that the product strength is low.

[0005] As described above, the prior art has a problem that the strength of the granulated material is insufficient and cannot be used as a substitute for sand. Therefore, it has not reached the stage where the cake composed of fine particles can be sufficiently and effectively used.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a granulated slag containing powdery slag which has a high crushing strength and can be suitably used as a substitute for sand, and a facility for producing the same. It is to be.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a particulate slag granulated material containing steelmaking slag, wherein the mass of CaO:
_{33~40%, SiO 2: 25~35%} , Al 2 O 3:
It has a substantially spherical shape and contains 6.5 to 12.5%, the percentage of the mass of the spherical particles having a diameter of 0.1 to 25 mm to the total mass is 90% or more, and the crushing strength is 5 to 5%. It is a slag granulated material having a weight of 20 kgf and a water immersion expansion coefficient specified by Japanese Industrial Standard A5015 of 0.5% or less.

According to the present invention, CaO, SiO ₂ , Al ₂
Since O ₃ is sufficiently contained, a hydrated cured product having binding properties is formed by the hydration reaction, and the slag granulated product can be sufficiently cured. This makes it possible to sufficiently increase the crushing strength of the granulated slag in combination with the spherical shape having no corners. Further, since the water immersion expansion coefficient is at a sufficiently low level, the formation of a hydrate showing volume expansion even when the slag granulated material comes into contact with rainwater or the like is prevented, and the slag granulated material can be prevented from collapsing. . Further, since the slag granulated material has a diameter of mostly in the range of 0.1 to 25 mm, it can be suitably used as a substitute for sand and ballas.

Further, the present invention provides a solid material composed of a powdered slag in a dry state and a powdery silica source and a cement-based solidified material in a dry state, and performs pulverization, kneading and granulation. Prepare a possible granulating device, charge the solid consisting of the powdery slag into the granulating device and pulverize in a dry state, after pulverization, the powdery silica source and cement-based solidified material in the granulating device The added and ground slag, the silica source and the cement-based solidification material are kneaded in a dry state, and after kneading, spherical particles are formed while adding water to the kneaded slag, silica source and the cement-based solidification material. After granulating and granulating,
This is a method for producing a slag granulated material, wherein spherical granulated particles are discharged from a granulating device and cured.

According to the present invention, after the ground slag is kneaded with the powdery silica source and the cement-based solidifying material,
It is granulated into spherical particles while adding water, and the granulated spherical granules are cured, so that Ca contained in the slag is contained.
A compound such as O or MgO, SiO ₂ and water preferentially undergo a hydration reaction to form a hydrated cured product having binding properties. This suppresses the hydration reaction between compounds such as CaO and MgO and water, thereby suppressing the formation of hydrates exhibiting volume expansion and preventing the occurrence of a collapse phenomenon due to volume expansion of spherical granulated particles. You. In addition, since the kneading is performed in a dry state, the mixing can be performed more uniformly than in the case where the kneading is performed in a water-containing state, and segregation can be eliminated. Thereby, the hydration reaction during curing can be promoted. Therefore, the crushing strength of the granulated slag, which is the granulated particles cured and hardened by these synergistic effects, can be sufficiently increased. In addition, since powdery slag is used as a compounding raw material, powdery slag can be effectively used.

[0011] The present invention also provides a slag supply device for supplying a solid material comprising powdery slag in a dry state;
And an additive supply device for supplying a powdered silica source and a cement-based solidifying material, and a solid material composed of powdered slag can be pulverized in a dry state, and the pulverized slag, the silica source, and the cement-based solidifying material A slag comprising: a granulating device capable of granulating spherical particles while adding water after kneading the slag in a dry state; and a curing means for curing the granulated spherical granulated particles. This is a production facility for granulated products.

According to the present invention, since the granulating apparatus has all the functions of pulverization, kneading and granulation, it is not necessary to separately provide apparatuses having the respective functions, and the configuration can be simplified. Become. Therefore, the size of the device can be reduced, and the construction cost can be reduced.

[0013] The present invention also provides a first drying and pulverizing apparatus for drying and pulverizing a solid material comprising powdery slag in a water-containing state,
A slag supply device for supplying the dried and crushed slag, a second drying and crushing device for drying and crushing a solid material comprising a hydrated silica source, a dried and crushed silica source, Additive-supplying device for supplying a cementitious solidified material in a state, slag supplied from the slag and the additive-supplying device, a kneading means capable of kneading the silica source and the cement-based solidifying material in a dry state, and kneaded. It comprises a granulating means capable of granulating spherical particles while adding water to the slag, silica source and cement-based solidifying material, and a curing means for curing the granulated spherical granulated particles. This is a facility for manufacturing slag granules.

According to the present invention, since the solid material composed of the powdery slag containing water is dried and pulverized by the first drying and pulverizing device, it is not necessary to separately provide a dryer and a pulverizer. In addition, since the conventional sun-drying of the solid material outdoors can be omitted, the drying time can be shortened and the space can be saved. Further, since the water-containing silica source is dried and pulverized by the second drying and pulverizing device, it is not necessary to separately provide a dryer and a pulverizer, and it is not necessary to obtain a dry powdery silica source. As a result, it is possible to expand the scope of obtaining the silica source, so that it is easy to obtain and the obtaining cost can be reduced.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The granulated slag of the present invention is used as a sand substitute and a ballast substitute, and is particularly used as a sand substitute for concrete aggregate. These products require the high crushing strength required to withstand compressive loads. The crushing strength is represented by a compressive load at the start of breaking of the slag granules under compressive stress. The term "slag granulated material" used in the present invention means that it is a granulated material containing powdery slag which is a steelmaking slag in terms of components, and is hardened by curing after granulation in terms of strength. Means granules. The uncured granules immediately after granulation are called granulated particles to distinguish them from slag granules.

The granulated slag is composed of Ca
_{O: 33~40%, SiO 2:} 25~35%, Al
₂ O ₃ : 6.5 to 12.5%, other oxides: 19.5 to
28.5%. The shape of the granulated slag is substantially spherical, and the particle size composition is such that the percentage of the mass of spherical particles having a diameter of 0.1 to 25 mm to the total mass is 90% or more. The granulated slag has a crushing strength of 5 to 20 kgf and a water immersion expansion coefficient of 0.5% or less. The water immersion expansion rate is
It is an index value for evaluating the expandability of steelmaking slag during water immersion, and is measured according to the test method specified in the Appendix of Japanese Industrial Standard A5015.

In the present embodiment, the raw material of the slag granulated material is
Solids consisting of powdered slag and silica
Iash and cement-solidified ordinary Portrun
Docement is used. Powder slag has a diameter of 1m
m, which is a fine slag of less than
Is collected as a cake-like solid from the settling tank. Further
In detail, powdery slag filters slurry in the settling tank.
As cake solid dehydrated by ilter press
Collected. Therefore, the powdery slag is hereinafter composed of
The solid is called slag cake. Slag cake is Ca
O, SiO_Two, Al_TwoO_Threeincluding. Fly ash is fine
Fine particles of ash contained in waste gas of pulverized coal combustion boiler
Is collected by a dust collector and melted to form fine spherical particles.
Has become a child. Fly ash is SiO_Two(Siri
F) and aluminosilicate. Normal Portrun
Cement (hereinafter abbreviated as cement) is CaO,
SiO _Two, Al_TwoO_Threeincluding.

The components of the granulated slag are limited as described above for the following reasons. CaO is a basic component necessary for securing the crushing strength of the granulated slag. C
The aO content is limited to 33-40%, the basic component is insufficient for the SiO ₂ and Al ₂ O ₃ of CaO% at acidic components of less than the lower limit, the hydration reaction after granulation This is because, when CaO% exceeds the upper limit, the acidic component becomes insufficient relative to the basic component, and the hydration reaction after granulation is suppressed. When the hydration reaction is suppressed, the precipitation of a hydrated cured product having binding properties is suppressed, and the slag granulated product is not sufficiently cured. Therefore, the crushing strength of the granulated slag cannot be ensured.

SiO ₂ is an acidic component necessary for securing the crushing strength of the granulated slag like CaO. S
The reason that the iO ₂ content is limited to 25 to 35% is that, when SiO ₂ % exceeds the upper limit, the ratio of the basic component to CaO is out of an appropriate range, and similarly, the hydration reaction after granulation is suppressed. This is because the crushing strength of the granulated slag cannot be secured. SiO ₂ % less than the lower limit
Then, as described above, CaO and MgO contained in the slag
Are compounds SiO ₂ and preferential hydration inhibition with water etc., CaO, since hydration reaction of the compound with water such as MgO occurs, formation of hydrated cured product capable of binding is inhibited The formation of a hydrate exhibiting volume expansion is promoted. Therefore, there is a possibility that a collapse phenomenon due to volume expansion of the granulated slag may occur.

Al ₂ O ₃ is an acidic component necessary to form an aluminosilicate material which reacts with water in the presence of CaO and hardens. Al ₂ O ₃ content of 6.5 to 12.5%
The reason is that if the Al ₂ O ₃ % is less than the lower limit, it is difficult to sufficiently form the substance after granulation, and the crushing strength of the granulated slag cannot be secured. . If the Al ₂ O ₃ % exceeds the upper limit, it is necessary to increase the amount of ordinary Portland cement that is the source of Al ₂ O ₃ , which increases the cost and increases the Ca content in the cement.
This is because the O content may cause the CaO content to exceed the upper limit, so that the crushing strength of the granulated slag cannot be ensured for the same reason as described above. Other oxides
It is an oxide such as MgO, MnO, and FeO, and is provided as an impurity of the compounding material. Other oxide content,
It is additionally determined by the amount of slag cake, fly ash and ordinary Portland cement.

The reason that the shape of the slag granulated product is substantially spherical is that the crushing strength of the spherical slag granulated material having no corners is smaller than the crushing strength of the slag granulated material having a cornered polyhedral shape due to the shape effect. It is because of high strength. The percentage of the mass of the spherical particles having a diameter of 0.1 to 25 mm to the total mass of the slag granulated product is limited to 90% or more by the ratio of the spherical particles having a diameter of 0.1 to 25 mm to the whole. Is less than 90%, the difference between the grain size composition of the slag granules and the grain size composition of the sand increases, and it becomes difficult to use the slag granules as a substitute for sand.

The lower limit of the diameter of the granulated slag is 0.1 mm.
The reason for this is that fine slag granules of less than 0.1 mm cannot function as concrete aggregate, and the upper limit of the diameter of the slag granules is 25.
The reason for the limitation to mm is that producing a granulated slag having a diameter exceeding 25 mm requires a long production time and makes it extremely difficult to control the operation of the granulating apparatus. In addition, the upper limit of the diameter of the slag granulated material of 25 mm is about the same as the upper limit of general crushed stone ballast, and the slag having a size exceeding the upper limit also applies to the application of the slag granulated material as a ballast substitute. This is because granulated materials are not required. When using granulated slag as a sand substitute,
It is preferable to configure the particle size distribution with a central particle diameter of 1 to 2 mm.

The crushing strength of the granulated slag is 5 to 20 kgf.
Is limited to the following reasons. The lower limit of the crushing strength is limited to 5 kgf, because if the crushing strength is lower than the lower limit, the slag granules may be crushed during transportation and handling by heavy machinery. The upper limit of the crushing strength is 2
The reason why the pressure is limited to 0 kgf is that although the crushing strength exceeding the upper limit value is very preferable in terms of characteristics, it is difficult to realize in terms of cost. The target value of the crushing strength of the granulated slag is preferably set to about 13 kgf of the crushing strength of natural sand. Crushing strength less than the crushing strength of natural sand is also acceptable, for example, in applications where compaction is used, such as for roadbed materials, when there is a material that collapses and becomes finer when compacted Is reduced and compaction is likely to occur. Crushing strength of granulated slag: 20 kg
f is the maximum crushing strength obtained in the above-mentioned component range, and is the crushing strength finally reached by curing for up to about three months.

The reason why the swelling coefficient of the slag granulated product is limited to 0.5% or less is as follows. The upper limit of the water immersion expansion coefficient is limited to 0.5%. When the water swelling expansion coefficient exceeds the upper limit, the slag granules expand when they come into contact with rainwater or the like, and collapse after a long period of time. This is because a serious result such as a decrease in the strength of the structure may be caused. Although the lower limit value of the water immersion expansion coefficient is not particularly limited, it is difficult to make the lower limit value less than 0.01% due to restrictions on components.

As described above, the slag granulated product of the present embodiment sufficiently contains CaO, SiO ₂ , and Al ₂ O _3, so that a hydrated cured product having binding properties is formed by the hydration reaction. Thus, the slag granules can be sufficiently cured. Thereby, the crushing strength of the granulated slag can be sufficiently increased in combination with the spherical shape having no corners. Most of the slag granules have a diameter of 0.1 to 25m.
Since it exists within the range of m, it can be suitably used as a substitute for sand and ballas. In addition, since the slag granulated material has a spherical shape, it can be particularly suitably applied as a sand substitute used in the sand compaction method of civil engineering work. More specifically, the sand compaction method, in which a hollow pile is driven into a weak place in the landfill and the sand is stuffed into the hollow pile, strengthens the ground. Although it is necessary to use spherical slag granules as a sand substitute, wear of the hollow pile can be reduced as compared with the case of using angular polyhedral granules and crushed sand. Further, since the water immersion expansion coefficient of the slag granules is limited to a low level, even if the slag granules may come into contact with rainwater or the like, a reduction in crushing strength can be prevented.

FIG. 1 is a system diagram showing a simplified configuration of a slag granulated material production facility 1 according to an embodiment of the present invention. The slag granulated material production equipment 1 includes a first slag supply device 3
, A first additive supply device 4, a granulation device 5, a conveying means 6 and a curing means 7. The first slag supply device 3 includes a slag hopper 9. The slag hopper 9 stores the dried slag cake and cuts out the slag cake by a predetermined amount.
Drying of the slag cake is performed by sun drying outdoors. The dried slag cake is charged into the slag hopper 9 by the shovel car 10, and the slag cake cut out from the slag hopper 9 is supplied to the granulating device 5 via the belt feeder 11, the belt conveyor 12 and the chute 13. Slug hopper 9, shovel car 10, belt feeder 11, belt conveyor 12, and chute 1
3 constitutes the first slag supply device 3.

The first additive supply device 4 includes fly ash supply means 14 and cement supply means 15. The fly ash supply means 14 includes a fly ash hopper 16
Is provided. The fly ash hopper 16 is in a dry state,
The powdered fly ash is stored and cut out by a predetermined amount. A level meter 17 and an air knocker 18 are attached to the fly ash hopper 16. Level meter 17
It has a low level meter 17a, a high level meter 17b, and an emergency stop level meter 17c, and detects that the amount of stored fly ash is an insufficient level, an excessive level, and an emergency stop level, and transmits a signal indicating the detected level. . The air knocker 18
It is realized by an air cylinder, and applies an impact to the fly ash hopper 16 to prevent the fly ash from hanging on the shelf.

The fly ash is pressure-fed to the fly ash hopper 16 from the fly ash jet pack vehicle 19 by pressurized air, and cut out from the slide gate 20 of the fly ash hopper 16. The cut fly ash is supplied to the additive hopper 26 via the fly ash cut-out conveyor 21, the chute 22, the bucket elevator 23, and the chute 24.

The cement supply means 15 includes a cement hopper 27. The cement hopper 27 stores the powdered cement in a dry state and cuts out the cement by a predetermined amount. A level meter 25 and an air knocker 44 having the same configuration as the fly ash hopper 16 are attached to the cement hopper 27. The level meter 25 has a low level meter 25a, a high level meter 25b, and an emergency stop level meter 25c. The cement is pumped to the cement hopper 27 by pressurized air from a cement jet pack truck 28 and cut out from the slide gate 29 of the cement hopper 27. The cut cement is supplied to the additive hopper 26 via a cement cutting conveyor 30, a chute 31, a bucket elevator 32, and a chute 33.

The additive hopper 26 stores the supplied fly ash and cement. A load cell 34 and a rotary feeder 35 are provided below the additive hopper 26.
Is provided. The load cell 34 includes the additive hopper 2
6, the weight of the fly ash and the cement stored in the feed hopper 6 is detected.
The fly ash and cement stored in 6 are supplied to the granulator 5. Fly ash supply means 14, cement supply means 15, additive hopper 26, load cell 3
4 and the rotary feeder 35 constitute the first additive supply device 4.

The granulating device 5 includes a stirring granulator 36.
The stirring granulator 36 has all the pulverizing, kneading and granulating functions as described later, and includes the first slag supply device 3 and the first
The raw material supplied from the additive supply device 4 is pulverized, kneaded, and granulated to form substantially spherical granulated particles.

FIG. 2 is a simplified sectional view showing the structure of the stirring granulator 36 shown in FIG. 1, and FIG. 3 is a plan view of FIG. The stirring granulator 36 includes a pan 37. The pan 37 is a circular dish-shaped container opened upward, and a housing 38.
Is placed within. The pan 37 has an axis 37 a inclined with respect to the horizontal plane, and is rotated around the inclined axis 37 a by a pan drive motor 39 provided on a housing 38. Raw materials such as slag cake, fly ash, and cement are charged into the pan 37. An opening / closing lid 40 is provided on an upper portion of the housing 38, and an agitator 41 and a scraper 42 are fixed to the opening / closing lid 40.

The agitator 41 is present in the pan 37 during operation, and is rotationally driven by the agitator drive motor 43 via a V-belt. Agitator 41 during operation
Is disposed at a position shifted from the inclined axis 37a. The scraper 42 is disposed close to the peripheral wall of the pan 37 and the inside of the bottom plate during operation, and scrapes off powder adhering to the peripheral wall and the bottom plate. The opening / closing lid 40 has a first
In addition, second material input ports 45 and 46 and a water supply port 47 are formed. The first raw material input port 45 is an opening for inputting slag cake, and the second raw material input port 46 is an opening for inputting fly ash and cement. An outlet 48 is formed in the bottom plate of the pan 37,
A sealing plate 49 is attached to the outlet 48. Sealing plate 4
9 is driven to be displaced by a hydraulic cylinder 50,
Open and close 8.

The slag cake can be crushed and pulverized by introducing the slag cake into the pan 37 from the first raw material charging port 45 and rotating the agitator 41 and the pan 37. After the pulverization, if fly ash and cement are added from the second raw material inlet 46 and the agitator 41 and the pan 37 are driven to rotate, the pulverized slag, fly ash and cement can be uniformly kneaded. Further, after kneading, if the agitator 41 and the pan 37 are rotationally driven while adding water from the water supply port 47, spherical granulated particles can be granulated. Thus, the granulating device 5
Since it has all the functions of pulverization, kneading, and granulation, it is not necessary to separately provide a pulverizer, a kneader, and a granulator, and the entire configuration of the apparatus can be simplified. Therefore, the size of the device can be reduced, and the construction cost can be reduced.

Referring again to FIG. 1, the first raw material input port 45, the second raw material input port 46, and the water supply port 47 of the stirring granulator 36 are connected to the chute 13 of the first slag supply device 3, Feeder 35 of material supply device 4, water supply means 5
3 respectively. The water supply means 53 includes a water supply pipe 54 and an on-off valve 55, and the on-off valve 5 during granulation.
5 is opened to supply water into the pan 37. A load cell 56 and a chute 57 are provided below the stirring granulator 36. The load cell 56 detects the charged weight of the slag cake supplied from the first slag supply device 3 and detects the total weight after adding fly ash and cement. The chute 57 is connected to the stirring granulator 36.
The granulated particles discharged from the discharge port 48 are guided to the conveying means 6. An air knocker 65 is attached to the chute 57. Agitation granulator 36, water supply means 53, load cell 5
6 and the chute 57 constitute the granulating device 5.

The transport means 6 has a belt conveyor 58. The granulated particles that have passed through the chute 57 are conveyed to the curing means 7 via the belt conveyor 58, the chute 59, and the belt conveyor 60. The curing means 7 includes first to third curing pits 61 to 63. First to third curing pits 61
63 are provided indoors, and the granulated particles are allowed to stand and cure for a predetermined curing time so as not to be exposed to rainwater. After the indoor curing, the slag granules are transported by the shovel car 64 and further cured outdoors.

FIG. 4 is a flowchart for explaining a method for producing a slag granulated product using the slag granulated particle producing apparatus 1 shown in FIG. In step a1, a raw material in a dry state is prepared. That is, a sun-dried slag cake, which is a main raw material, and powdery fly ash and cement, which are additives, are prepared. In step a2,
The slag cake is charged into the stirring granulator 36, and is crushed and pulverized in a dry state. The pulverization conditions are set to an agitator rotation speed of 1000 rpm or more and a pan rotation speed of 50 rpm or less. The rotation directions of the agitator 41 and the pan 37 are set to be opposite to each other. This processing is necessary for the following reasons. As described above, since the slag cake contains CaO, SiO ₂ , and Al ₂ O ₃ and has properties close to that of cement, the sun-dried slag cake is hardened. Therefore, granulation cannot be performed as it is, and it is necessary to perform crushing and pulverization. Further, in order to secure the crushing strength after curing, it is necessary to make the distribution of the slag and the additive uniform. For that purpose, it is necessary to make the slag into a sufficiently fine and uniform particle state, and it is important to crush and pulverize the slag cake.

In step a3, fly ash and cement are added. This process is performed by adding fly ash and cement into the pan 37 containing the crushed slag. In step a4, kneading is performed. This treatment is performed in a dry state and under the same conditions as pulverization conditions. That is, the bread 37
The rotation directions of the motor and the agitator 41 are set to be opposite to each other. The reason why the kneading is performed in a dry state is that segregation due to water as a binder can be prevented as compared with the case where the kneading is performed in a water-containing state, and the rotation direction of the pan 37 and the agitator 41 is reversed. The reason for the kneading is that it is easy to mix uniformly by the countercurrent effect. This makes it possible to uniformly mix slag, fly ash, and cement to eliminate segregation, and obtain the target crushing strength of slag granules with the minimum amount of fly ash and cement added. Can be. Therefore, the manufacturing cost can be reduced.

In step a5, granulation is performed. The granulation is carried out by stirring the mixture with the agitator 41 while adding water from the water supply means 53 to the kneaded mixed powder. The granulation conditions are set to an agitator rotation speed of 800 rpm or less and a pan rotation speed of 50 rpm or less. The rotation directions of the agitator 41 and the pan 37 are set to be opposite to each other. Thereby, spherical granulated particles are efficiently granulated. In the granulation, the particle size composition of the slag granulated product is the diameter:
The reaction is performed so that the percentage of the mass of the spherical particles having a diameter of 0.1 to 25 mm with respect to the total mass is 90% or more.

At step a6, curing is performed. Curing is performed by leaving the granulated particles indoors, that is, standing for a predetermined time, for example, 12 hours without being exposed to rainwater, and then storing them outdoors for a long period of time, for example, one month.
Since the hydration reaction of the granulated particles proceeds by this treatment,
A hydrated cured product having the above-described binding properties is formed, and the crushing strength of the granulated product is improved. This processing is necessary for the following reasons. The granulated particles immediately after granulation have very little crushing strength because the hydration reaction hardly progresses. Therefore, the transport operation by a heavy machine or the like will cause the granulated particles to collapse. Exposure to rainwater before the hydration reaction starts also causes the disintegration of the granulated particles.
Therefore, the granulated particles immediately after granulation need to be left stationary without moving until the hydration reaction proceeds.

As described above, CaO, SiO ₂ , Al ₂ O ₃
After the powder slag containing is kneaded with fly ash as a silica source and cement as a solidifying material, granulation is performed while adding water, so that a hydrated cured product having binding properties can be formed. it can. In a dry state and bread 3
Since the kneading is performed by reversing the rotation direction of the agitator 7 and the agitator 41, the occurrence of segregation due to the water serving as a binder can be prevented as compared with the case where the kneading is performed in a water-containing state, and the counter-current effect allows uniformity It becomes possible to mix. As a result, a uniform mixed state without segregation can be realized, so that the hydration reaction during curing can be promoted. Therefore, it is possible to increase the crushing strength of the granulated slag by the synergistic effect.
In addition, since powdery slag can be used as a main raw material, it is possible to effectively use powdery slag.

FIG. 5 is a system diagram showing a simplified configuration of a slag granulated material manufacturing equipment 66 according to another embodiment of the present invention. The slag granulated material manufacturing equipment 66 is similar to the slag granulated material manufacturing equipment 1, and corresponding parts are denoted by the same reference numerals. It should be noted that an apparatus for drying and pulverizing a water-containing raw material is provided, and that a kneading unit and a granulating unit are separately provided. In the slag granulated material production facility 66, a slag cake in a hydrated state, a silica source in a hydrated state, and cement, which is a powdery cement-based solidifying material in a dry state, are used as raw materials. The silica source is
For example, cake-like sand-washing sludge generated when sand is collected from soil by sand-washing treatment (hereinafter referred to as sludge cake)
It is.

The slag granulated material production equipment 66 includes first and second dry and crushing devices 67 and 68 and a second slag supply device 6.
9, a second additive supply device 70, a kneading machine 71 as a kneading means, a rolling granulator 73 as a granulating means, a conveying means 6 and a curing means 7.

The water-containing slag cake is conveyed by the shovel car 10 and supplied to the first drying and crushing device 67 via the belt conveyor 75. First dry crusher 6
7 dries and pulverizes the water-containing slag cake, and discharges the pulverized slag onto the carry-out belt conveyor 76.

FIG. 6 is a simplified front view showing the structure of the first drying and pulverizing device 67 shown in FIG. 5, and FIG. 7 is a plan view of FIG. The first drying and pulverizing device 67 includes a rotary kiln 7.
8 and a hot air generator 79. Rotary kiln 78
Is a rotating body rotatable around the axis 78a and has a substantially cylindrical shape. A raw material input hopper 80 is provided at one axial end of the rotary kiln 78, and a discharge hopper 81 is provided at the other axial end. Hereinafter, for convenience of explanation, the axis 78 of the rotary kiln 78 will be described.
One end side in the a-direction (the right side in FIG. 6) is called an entrance side, and the other end side is called an exit side. A hot air generating furnace 79 is provided near the raw material input hopper 80, and an exhaust duct 82 for guiding exhaust gas to a dust collector is provided near the discharge hopper 81.

The hot air generating furnace 79 has a furnace body 84, and a burner 85 is attached to the furnace body 84. Burner 85
Is a direct-fired burner that directly burns combustion gas
8 is injected. A blower 86 is provided near the burner 85, and the blower 86 supplies combustion air to the burner 85 via a duct 87. Further, a fan 88 is provided near the furnace body 84, and the fan 88 supplies dilution air into the furnace body 84 via a duct 89.
The combustion gas of the burner 85 is diluted by dilution air and supplied to the rotary kiln 78 as hot air. Since the hot air is supplied from the inlet side of the rotary kiln 78, the slag cake in a water-containing state can be rapidly dried.

FIG. 8 is a simplified front view of the rotary kiln 78 shown in FIG. 6, FIG. 9 is a plan view of FIG. 8, FIG. 10 is a right side view of FIG. Figure 8
FIG. The rotary kiln 78 includes a drum 90
And crushing means 91. The drum 90 is a rotating container having a substantially cylindrical shape, and is rotatably supported coaxially with the axis 78a by first and second support means 93 and 94. The first support means 93 includes a pair of support rollers 95 arranged at intervals in the circumferential direction of the drum 90.
, And each support roller 95 is in contact with a tire 96 provided on the outer peripheral surface of the drum 90. Each support roller 95 has an axis parallel to the axis 78a, and both ends of the roller shaft are rotatably supported by a pair of brackets 97. The second support means 94 includes a first support means 93.
And is arranged at an interval from the first support means 93 in the direction of the axis 78a.

A drum driving means 99 is provided between the first and second support means 93 and 94. The drum driving means 99 includes the first and second sprocket wheels 10.
0, 101 and a drum drive motor 103. First
The sprocket wheel 100 is provided near the drum 90, and is driven to rotate about an axis parallel to the axis 78a by a drum drive motor 103. The second sprocket wheel 101 is provided on the outer peripheral surface of the drum 90 so as to face the first sprocket wheel 100, and is connected to the first sprocket wheel 100 via a transmission chain 104. The rotation of the drum drive motor 103 is transmitted to the drum 9 via the first sprocket wheel 100, the transmission chain 104 and the second sprocket wheel 101.
0 to rotate the drum 90 about the axis 78a.

A feed screw 113 is provided below the raw material input hopper 80, and a discharge screw 114 is provided below the discharge hopper 81. The carry-in screw 113 and the discharge screw 114 are driven by the input screw drive motor 113a and the discharge screw drive motor 114a, respectively. The input screw 113 feeds the raw material input from the belt conveyor 75 into the raw material input hopper 80 into the drum 90, and the discharge screw 114 discharges the dried and pulverized raw material onto the discharge belt conveyor 76.

The crushing means 91 comprises a stirring blade 106 and a stirring shaft 1.
07. The stirring blade 106 is a member for stirring and pulverizing the raw material in contact with the raw material charged into the drum 90, and is detachably attached to the stirring shaft 107. A plurality (12 in this embodiment) of the stirring blades 106 are provided at intervals in the direction of the axis 107 a of the stirring shaft 107, and the distance L 1 between the stirring blades 106 is from the input side to the output side of the rotary kiln 78. It is set so that it becomes shorter as it goes toward. The stirring shaft 107 is a rotating shaft inserted into the drum 90 and extends in parallel with the axis 78 a of the drum 90. Both ends of the stirring shaft 107 are rotatably supported by a pair of brackets 108 outside the both ends of the drum 90. A stirring blade drive motor 109 is provided near the entrance side of the rotary kiln 78, and the stirring blade drive motor 109 rotates the stirring shaft 107 via a V-belt 110.

The raw material charged into the rotating drum 90 advances from the inlet side to the outlet side while repeatedly rising and falling along the inner wall of the drum 90, and comes into contact with the rotating stirring blades 106 to be released. Crushed and crushed. Further, since the hot air is supplied from the hot air generating furnace 79 into the drum 90, the drying of the raw material proceeds while the raw material is crushed. Since the drying rate of the raw material increases as the surface area increases as the material becomes finer, it is possible to increase the drying rate by simultaneously performing pulverization and drying. Therefore, by providing the first drying and pulverizing device 67, the raw material can be efficiently dried and pulverized. Further, as described above, the distance L1 between the stirring blades 106
Is set so as to decrease from the entry side to the exit side, so that when the size of the raw material is large, the interval L1 is set to be wide, and as the raw material is crushed and made fine, the interval L1 is set to be small. Will be. As a result, clogging of the raw material can be prevented, and as the raw material becomes finer, the pulverizing force can be enhanced, and the particle size of the raw material after pulverization can be reduced.

Referring to FIG. 5 again, the pulverized slag discharged onto discharge belt conveyor 76 is conveyed and stored in slag hopper 116. The pulverized slag stored in the slag hopper 116 is cut out from the slag hopper 116 via a rotary feeder 117, and a cut-out conveyor 118.
Is supplied to the kneading machine 71 via the The discharge belt conveyor 76, the slag hopper 116, the rotary feeder 117 and the cut-out conveyor 118 are provided with a second slag supply device 69.
Is configured.

The hydrous sludge cake, which is a silica source,
It is conveyed by the shovel car 120 and supplied to the second drying and crushing device 68 via the belt conveyor 121. The second drying and pulverizing device 68 has the same configuration as the first drying and pulverizing device 67, and dries and pulverizes the sludge cake, and discharges powdery sand-washed sludge onto the carry-out belt conveyor 122.

The second additive supply device 70 includes a silica source supply means 123 and a cement supply means 124.
The silica source supply means 123 includes a silica source hopper 125. The configuration of the silica source hopper 125 is the same as the configuration of the fly ash hopper 16. The powdery washing sludge discharged onto the carry-out belt conveyor 122 is conveyed and stored in the silica source hopper 125. Silica source hopper 1
The powdered washing sand sludge stored in the hopper 25 is a silica source hopper 1
25 is cut out through a slide gate 126 and supplied to an additive hopper 26 through a cut-out conveyor 127. Unloading belt conveyor 122, silica source hopper 12
5, the slide gate 126, the cutting conveyor 127,
The silica source supply means 123 is constituted.

The cement supply means 124 stores the cement in a dry state and cuts the cement by a predetermined amount.
Is provided. Cement is a cement jet pack car 28
From the cement hopper 27 by pressurized air,
It is cut out from the slide gate 29. The cut cement is supplied to the additive hopper 26 via the cement cutting conveyor 30. Cement jet pack car 28,
The cement hopper 27, the slide gate 29, and the cut-out conveyor 30 constitute a cement supply unit 124. The additive hopper 26 stores the supplied washing sludge and cement. The washing sludge and cement are supplied to the load cell 34.
Kneading machine 71 via the rotary feeder 35
Supplied to The silica source supply unit 123, the cement supply unit 124, the additive hopper 26, the load cell 34, and the rotary feeder 35 constitute a second additive supply unit 70.

The kneading machine 71 includes the main body 129 and the stirring means 13.
0. In the upper part of the main body 129, the slag inlet 1
29a and an additive inlet 129b are formed.
Pulverized slag is supplied from the slag input port 129a, sand washing sludge and cement are input from the additive input port 129b, and the stirring blade 130a of the stirring means 130 is driven to rotate by the motor 130b. It is kneaded with the cement in a dry state. The kneaded mixed powder is supplied to an outlet 129c formed in the lower portion of the main body 129.
Is discharged from. A load cell 1 is provided below the kneader 71.
31 are provided. The load cell 131 measures the weight of the pulverized slag and the total weight after adding the washing sand sludge and the cement. The mixed powder discharged from the discharge port 129c is supplied to the rolling granulator 73 via the chute 132 and the cut-out conveyor 133. The tumbling granulator 73 granulates the mixed powder into spherical particles.

FIG. 12 is a simplified perspective view showing the structure of the rolling granulator 73 shown in FIG. The rolling granulator 73 is
A pan 134 is provided. The pan 134 is a circular dish-shaped container opened upward, and is rotationally driven by a pan drive motor 135 in a state inclined with respect to a horizontal plane. The mixed powder is put into a pan 134, and while adding water, the
When 4 is rotated, the mixed powder circulates in the pan 134 while being coated with moisture, and rolls to granulate into spherical particles. When the granulated particles reach a predetermined particle size, they are discharged from the periphery of the pan 134 into the chute 136. On the inner side of the peripheral wall of the pan 134, a scraper 137 is provided close to the peripheral wall. Scraper 137
Scrapes off the powder adhering to the peripheral wall of the pan 134. The particle size of the granulated particles is adjusted by the rotation speed of the pan 134 and the like.

Referring again to FIG. 5, the granulated particles discharged into chute 136 of rolling granulator 73
6 guides the transfer means 6. The transport means 6 is shown in FIG.
In the same manner as in the embodiment shown in FIG.
8, conveyed to the curing means 7 via the chute 59 and the belt conveyor 60. The curing means 7 converts the granulated particles into the first indoor
-Stored in the third curing pits 61 to 63 for a predetermined time to harden the granulated particles. After indoor curing, the hardened granules are transported by the shovel car 64 and further cured outdoors.

As described above, in this embodiment, both the drying and the pulverization can be performed by the first and second drying and pulverizing devices 67 and 68, so that it is not necessary to separately provide the dryer and the pulverizer. . Therefore, the equipment configuration can be simplified.

FIG. 13 is a flowchart for explaining a method for producing a slag granulated product using the slag granulated particle producing equipment 66 shown in FIG. In step b1, a dry powdered cement is prepared. In step b2, drying and pulverization of the slag cake in a water-containing state are performed in the first drying and pulverizing device 67. In step b3, the pulverized slag is put into the kneader 71. Step b
In No. 4, drying and pulverization of the sludge cake in a hydrated state are the second steps.
This is performed in the drying and crushing device 68, and in step b5,
The ground sand and sludge are added to the kneader 71.

In step b6, kneading is performed, and the pulverized slag, sand-washed sludge, and cement are kneaded. Step b
In 7, the kneaded mixed powder is tumbled and granulated. The tumbling granulation is performed by putting the mixed powder into the pan 134 of the tumbling granulator 73 and rotating the pan 134 while adding water. Thereby, spherical particles are granulated. In step b8, curing of the granulated spherical granulated particles is performed. Curing is performed by allowing the granulated particles to stand indoors for a predetermined time, for example, 12 hours, and then storing them outdoors for a long period of time, for example, one month. As a result, a hydrated cured product having the above-described binding properties is formed, and the crushing strength of the granulated slag is improved.

As described above, since the slag granules can be granulated using the slag cake in a water-containing state, the sun drying of the slag cake can be omitted. As a result, the drying time can be reduced and the space can be saved. Further, since a slag granulated product can be produced using a sludge cake in a water-containing state as a silica source, it is not necessary to obtain a powdery silica source in a dry state. This makes it possible to expand the range of silica sources to be obtained, so that it is easy to obtain and the acquisition cost can be reduced. In addition, since slag granules having high crushing strength can be produced using a slag cake composed of powdered slag and a sludge cake composed of sand-washed sludge, the powdered slag and sand-washed waste that have been disposed of can be produced. Sludge can be used effectively.

Example 1 A slag granulated product was manufactured according to the present invention, and various characteristic values were measured to evaluate the slag granulated product. The production of the slag granulated product was performed according to the production method shown in FIG. 4 using the slag granulated product manufacturing equipment 1 shown in FIG. The characteristic values were measured for particle size composition, crush strength, water immersion expansion coefficient, bulk specific gravity, and collapse rate. The granularity configuration is
The mass of the granulated particles having a diameter of 0.1 to 25 mm was expressed as a percentage with respect to the total mass. The crushing strength was measured by compressing the slag granules one by one with a testing machine (Autograph manufactured by Shimadzu Corporation) and measuring the maximum compressive load at the time of breaking, and expressing the obtained maximum compressive load as the crushing strength (kgf / piece). did. The lowering speed of the crosshead during compression was set to 2 mm / min. The disintegration rate was determined by charging the slag granules into an autoclave at the following temperature:
Treated under the conditions of 215 ° C. and holding time: 3 hours, measured the particle size distribution of the treated slag granules, and measured the sieve opening 1 m
m expressed as a percentage by mass passed. The disintegration rate indicates the content of the hydrate showing the volume expansion. Table 1 shows the production conditions of the slag granules.

[0064]

[Table 1]

The raw material slag cake used was a sun-dried one, and the fly ash and ordinary Portland cement used were in a dry state. The slag cake is charged into the pan 37 of the stirring granulator 36, crushed and crushed under the crushing conditions shown in Table 1, and after crushing, fly ash and ordinary Portland cement are added and dried under the same conditions as in the crushing treatment. After kneading, granulation is performed under the granulation conditions shown in Table 1 while gradually adding water, and after granulation, the granulated particles are cured under the curing conditions shown in Table 1 to obtain a slag granulated product. Manufactured.

The components of the slag granules after curing are as follows: 38% by weight of CaO, 30% by weight of SiO ₂ , 7% by weight of Al ₂ O ₃ :
Other oxides: 25%. Table 2 shows the characteristic values of the granulated slag.

[0067]

[Table 2]

From Table 2, it can be seen that the characteristics of the granulated slag are good for each characteristic value. Therefore, the granulated slag of the present invention can be suitably used as a substitute for sand and ballas.

(Examples 2 to 5 and Comparative Example 1) The slag granulated products of Examples 2 to 5 satisfying the conditions of the present invention and the slag granulated products of Comparative Example 1 deviating from the conditions of the present invention were produced. The crushing strength and collapse rate of the granulated slag were measured and evaluated.
The slag granules of Examples 2 to 5 were produced under the same conditions as Example 1 except for the pulverization conditions. In Comparative Example 1, a slag granulated product was produced by omitting the slag cake pulverizing treatment. Other conditions of Comparative Example 1 were set to the same conditions as Example 1. In Comparative Example 1, the slag cake crushing treatment was omitted, and therefore, a slag cake with few lump was used. Table 3 shows the manufacturing conditions and characteristic values of Examples 2 to 5 and Comparative Example 1.

[0070]

[Table 3]

From Table 3, all the slag granules of Examples 2 to 5 show good crushing strength and collapse rate, whereas the slag granulation of Comparative Example 1 has very low crushing strength.
It can also be seen that the collapse rate is high. This indicates that it is important to sufficiently crush and pulverize the slag cake to produce a slag granulated product. Also, as shown in Examples 2 to 5, it can be seen that the crushing strength of the granulated slag increases as the grinding conditions are strengthened, that is, as the agitator rotation speed and the grinding time during the grinding are increased and the grinding time is increased. This also shows that it is important to pulverize the slag cake sufficiently.

As described above, the slag granulated material manufacturing equipment 66 shown in FIG. 5 is provided with the second drying and pulverizing device 68 so as to dry and pulverize a water-containing silica source. Alternatively, the second dry pulverizing device 68 may be omitted using a dry powdery silica source. Further, in the present invention, fly ash and washing sand sludge are used as the silica source, but the present invention is not limited to this, and other substances may be used. Although curing is performed at room temperature after granulation, curing may be performed by hydrothermal treatment in a high-temperature, high-pressure steam atmosphere. Although ordinary Portland cement is used as a cement-based solidifying material, an early-strength Portland cement, a blast furnace cement, or the like may be used.

[0073]

As described above, according to the first aspect of the present invention, since CaO, SiO ₂ , and Al ₂ O ₃ are sufficiently contained, a hydrated cured product having a binding property by a hydration reaction. Are formed, and the slag granules can be sufficiently cured. This makes it possible to sufficiently increase the crushing strength of the granulated slag in combination with the spherical shape having no corners. Also, since the water immersion expansion coefficient is sufficiently low,
Even when the slag granules come into contact with rainwater or the like, the formation of a hydrate showing volume expansion is prevented, and the slag granules can be prevented from collapsing. Most of the slag granules have a diameter of 0.1 ~
Since it exists within the range of 25 mm, it can be suitably used as a substitute for sand and ballas.

According to the second aspect of the present invention, the ground slag, the powdery silica source and the cement-based solidifying material are kneaded, and then granulated into spherical particles while adding water. Cured spherical granulated particles are cured, so that compounds such as CaO and MgO contained in the slag, SiO ₂ and water preferentially undergo a hydration reaction to form a hydrated cured product having bonding properties. Is done. This suppresses the hydration reaction between compounds such as CaO and MgO and water, thereby suppressing the formation of hydrates exhibiting volume expansion and preventing the occurrence of a collapse phenomenon due to volume expansion of spherical granulated particles. You. In addition, since the kneading is performed in a dry state, the mixing can be performed more uniformly than in the case where the kneading is performed in a water-containing state, and segregation can be eliminated. Thereby, the hydration reaction during curing can be promoted. Therefore, the crushing strength of the granulated slag, which is the granulated particles cured and hardened by these synergistic effects, can be sufficiently increased. Further, since powdery slag is used as a raw material, powdery slag can be effectively used.

According to the third aspect of the present invention, since the granulating apparatus has all the functions of pulverization, kneading and granulating, it is not necessary to separately provide apparatuses having the respective functions, and the structure is simplified. Can be realized. Therefore,
The size of the device can be reduced, and the construction cost can be reduced.

According to the fourth aspect of the present invention, the first
Since the solid material composed of the water-containing powdery slag is dried and pulverized by the drying and pulverizing device, it is not necessary to separately provide a dryer and a pulverizer. In addition, since the conventional sun-drying of the solid material outdoors can be omitted, the drying time can be shortened and the space can be saved. In addition, since the water-containing silica source is dried and pulverized by the second drying and pulverizing device, it is not necessary to separately provide a dryer and a pulverizer,
There is no need to obtain a dry powdered silica source. As a result, it is possible to expand the scope of obtaining the silica source, so that it is easy to obtain and the obtaining cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a simplified configuration of a slag granulated material production facility 1 according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a simplified configuration of a stirring granulator 36 shown in FIG.

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is a flowchart for explaining a method of manufacturing a slag granulated product using the slag granulated product manufacturing equipment 1 shown in FIG.

FIG. 5 is a system diagram showing a simplified configuration of a slag granulated material production facility 66 according to another embodiment of the present invention.

FIG. 6 is a simplified front view showing a configuration of a first drying and pulverizing device 67 shown in FIG. 5;

FIG. 7 is a plan view of FIG. 6;

8 is a simplified front view showing the configuration of the rotary kiln 78 shown in FIG.

FIG. 9 is a plan view of FIG. 8;

FIG. 10 is a right side view of FIG.

FIG. 11 is a left side view of FIG.

FIG. 12 is a simplified perspective view showing a configuration of a rolling granulator 73 shown in FIG. 5;

FIG. 13 is a flowchart for explaining a method of manufacturing a slag granulated product using the slag granulated material manufacturing equipment 66 shown in FIG.

[Explanation of symbols]

 1,66 Slag granulated material manufacturing equipment 5 Granulating device 7 Curing means 36 Stirring granulator 37 Pan 41 Agitator 42 Scraper 53 Water supply means 67 First drying and crushing device 68 Second drying and crushing device 71 Kneader 73 Rolling Grain machine

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kenichi Katayama 4976 Nomura Minamicho, Shinnanyo-shi, Yamaguchi Prefecture Inside Nisshin Steel Co., Ltd. Shunan Steel Works (72) Inventor Tetsuya Matsushita 3-chome 6 Makura, Kokurakita-ku, Kitakyushu-shi, Fukuoka Prefecture No.42 Inside Japan Magnetic Separation Co., Ltd.

Claims (4)

[Claims] 1. A granulated slag containing steelmaking slag, comprising 33 to 40% by mass% of CaO and 25 to 35% by mass of SiO _2.
%, Al ₂ O ₃ : 6.5 to 12.5%, has a substantially spherical shape, and the percentage of the mass of spherical particles having a diameter of 0.1 to 25 mm to the total mass is 90% or more. Has a crushing strength of 5 to 20 kgf.
A granulated slag characterized by having a water immersion expansion coefficient specified in 5015 of 0.5% or less. 2. A solid material comprising a powdery slag in a dry state, and a powdery silica source and a cement-based solidification material in a dry state, respectively, are prepared, and pulverization, kneading and granulation can be performed. A granulation device is prepared, and the solid material comprising the powdery slag is charged into a granulation device and pulverized in a dry state. After the pulverization, a powdery silica source and a cement-based solidifying material are added to the granulation device. The ground slag, the silica source and the cement-based solidifying material are kneaded in a dry state, and after kneading, spherical particles are granulated while adding water to the kneaded slag, the silica source and the cement-based solidifying material, A method for producing a granulated slag, comprising discharging granulated spherical particles from a granulator after granulation and curing. 3. A slag supply device for supplying a solid material composed of dry powder slag, an additive supply device for supplying a dry silica powder and a cement-based solidifying material, and powder slag. Solid matter comprising a dry solid state, and after kneading the ground slag with the silica source and cement-based solidifying material in a dry state, granulating into spherical particles while adding water. A slag granulation production facility, comprising: a granulation device; and a curing means for curing granulated spherical granulated particles. 4. A first drying and pulverizing device for drying and pulverizing a solid material comprising a powdery slag in a water-containing state, a slag supply device for supplying a dried and pulverized slag, and a solid material comprising a silica source in a water-containing state Drying and pulverizing apparatus for drying and pulverizing, a dry and pulverized silica source, an additive supply apparatus for supplying a dry and powdery cement-based solidified material, and the slag and additive supply apparatus Means that can knead the slag, silica source and cement-based solidified material supplied from the company in a dry state, and can granulate spherical particles while adding water to the kneaded slag, silica source and cement-based solidified material A production facility for slag granules, comprising: granulating means; and curing means for curing granulated spherical granulated particles.