WO2021153346A1 - Method and device for manufacturing slag material - Google Patents

Abstract

Provided is a method for manufacturing a slag material, the method making it possible to adjust the characteristics of the slag material using a simpler method. A method for manufacturing a slag material, the method including: granulating a molten slag material S1 and then cooling the same, whereby the exterior of the slag material S1 is solidified to form an external shell, and the interior of the slag material S1 forms partially solidified semi-molten slag particles S2; and cooling the semi-molten slag particles S2. The semi-molten slag particles S2 may be held within a prescribed temperature range above normal temperature for a prescribed time prior to cooling.

Description

Manufacturing method and equipment for slag material

This application claims priority based on Japanese application 2020-14685, which is a Japanese application filed on January 31, 2020, and based on the same application. This application is incorporated herein by reference in its entirety.

The present invention relates to a method for manufacturing a slag material and a manufacturing apparatus, and particularly to a method for manufacturing a slag material using ferronickel slag.

Slag discharged from steelmaking processes, alloy refining processes, etc. is used as a fine aggregate used in the production of cement concrete (hereinafter referred to as concrete) and cement mortar (hereinafter referred to as mortar). In recent years, slag has been used as a substitute for natural materials such as river sand, land sand, crushed sand, and sea sand from the viewpoint of environmental protection. Japanese Patent Application Laid-Open No. 2019-163175 describes a step of making steelmaking slag into droplets and flying them in the air (wind crushing), and colliding the flying steelmaking slag with a recovery plate or a strut standing up from the recovery plate to condense and solidify. A step of making the slag material and a method for producing the slag material including the slag material are disclosed. Further, Japanese Patent Application Laid-Open No. 2019-163175 describes that the composition of the slag changes depending on the flight distance of the steelmaking slag. Japanese Patent No. 60070614 discloses a method for producing a slag material having a high flatness by wind-crushing steelmaking slag at 1550 ° C. or higher and causing it to collide with a wall surface.

The quality of concrete and mortar may be affected by the physical structure and physical characteristics of the slag material used as the fine aggregate. On the other hand, the desirable properties of the slag material depend on the intended use and mode of use of concrete and mortar, and therefore cannot be uniformly determined. Therefore, it is desirable to be able to manufacture slag materials having different characteristics with one manufacturing facility. However, when adjusting the flight distance of the slag to adjust the characteristics of the slag, as disclosed in Japanese Patent Application Laid-Open No. 2019-163175, it is necessary to take measures such as providing a plurality of tsuitates, and the manufacturing equipment must be provided. The influence of is large.

An object of the present invention is to provide a method for producing a slag material in which the characteristics of the slag material can be adjusted by a simpler method.

In the method for producing a slag material of the present invention, by granulating and cooling the molten slag, the outside is coagulated and solidified to form an outer shell, and the inside is partially coagulated and solidified to form semi-molten slag particles. It also has the ability to cool the semi-molten slag particles.

According to the present invention, it is possible to provide a method for producing a slag material in which the characteristics of the slag material can be adjusted by a simpler method.

The above-mentioned and other purposes, features, and advantages of the present application will be apparent by the detailed description described below with reference to the accompanying drawings exemplifying the present application.

It is a conceptual diagram which shows the manufacturing method of a slag material.

Hereinafter, embodiments of the method for producing the slag material of the present invention will be described with reference to the drawings. The slag material is used as a fine aggregate of a concrete composition or a mortar composition (hydrated cured product). These hydrated cured products contain cement, an aggregate containing a slag material, water, and may contain a swelling material. FIG. 1 shows a conceptual diagram of a slag material manufacturing apparatus 1 and a manufacturing method. Molten slag is supplied to the manufacturing apparatus 1. The molten slag is ferronickel slag in a molten state (hereinafter referred to as FeNi slag S1), but is not limited thereto. The FeNi slag S1 is directly infused from the lower part of the ferronickel refining electric furnace into the wind crusher 2 via the slag gutter 3. The temperature of the FeNi slag S1 supplied to the wind blower 2 is about 1500 to 1600 ° C.

The manufacturing apparatus 1 has a high-pressure air supply nozzle 4 that opens inside the wind blower 2, and a blower 5 that is connected to the supply nozzle 4 and supplies high-pressure air to the supply nozzle 4. The air volume and speed of the high-pressure air can be adjusted by controlling the rotation speed of the blower 5. High-pressure air is directly blown onto the FeNi slag S1 supplied to the wind crusher 2, and the FeNi slag S1 is decomposed into a large number of molten particles by the air flow. The particles fly in the internal space of the windbreaker 2 by the air flow of high-pressure air. During this time, the particles are cooled and the outside is condensed and solidified to form an outer shell. The inside of the particles partially condenses (crystallizes) by starting crystallization in the molten slag as the slag temperature drops, but does not coagulate and solidify as a whole. Such particles are referred to as semi-molten slag particles S2. Further, such a state inside the particles is called a semi-molten state. As long as the outside of the particles is condensed and solidified to form an outer shell and the inside of the particles is partially condensed and solidified, the outer shell of the semi-molten slag particles S2 may be crystalline or amorphous. May be good. No temperature control is performed inside the wind crusher 2. By air-crushing the FeNi slag S1, the FeNi slag S1 can be atomized and the particleized FeNi slag S1 can be uniformly cooled during flight.

A collision plate 6 is provided at a position opposite to the slag gutter 3 in the internal space of the wind crusher 2. The flying semi-molten slag particles S2 collide with the collision plate 6, change their direction, descend by gravity, and are discharged from the discharge port 7 at the bottom of the wind crusher 2. The temperature of the discharged semi-molten slag particles S2 drops to about 1300 ° C., but the inside of the particles is still in a semi-molten state. That is, the particles remain semi-molten slag particles S2. In the present embodiment, the distance from the tip of the slag gutter 3 to the collision plate 6 is about 18 m, and ^{high-pressure air having a wind speed of 120 m / s and a flow rate of 810 Nm 3} / min is supplied from the two supply nozzles 4. The flight time from the tip of the slag gutter 3 of the particles to the collision plate 6 is estimated to be about 1 second, and the above-mentioned semi-molten slag particles S2 can be formed under these conditions.

The semi-molten slag particles S2 discharged from the wind crusher 2 are sent to the storage container 11 by batch processing. The semi-molten slag particles S2 are temporarily received by the hopper 8 provided directly below the discharge port 7. When the container 9 is ready to be received, the hopper 8 rotates to supply the semi-molten slag particles S2 to the container 9. The container 9 is transported by the conveyor 10 to the upper part of the storage container 11 (storage tank). A supply port 12 for the semi-molten slag particles S2 is provided at the upper part of the storage container 11, and a discharge port 13 for the semi-molten slag particles S2 is provided at the bottom. The container 9 is rotated by a first driving device 15 provided on the upper portion of the storage container 11 to supply the semi-molten slag particles S2 to the storage container 11. The discharge port 13 is provided with a gate 14 for opening and closing the discharge port 13. The gate 14 can be opened and closed by a second drive device 16 provided at the bottom of the storage container 11.

The supply of the semi-molten slag particles S2 and the opening and closing of the gate 14 are controlled by the control device 17. Here, for the sake of simplicity, it is assumed that the amount of the semi-molten slag particles S2 transported in the container 9 is constant in each batch. Further, it is assumed that the gate 14 of the storage container 11 is intermittently opened and closed, and a single opening operation discharges an amount of particles corresponding to one batch. The control device 17 stores a batch of semi-molten slag particles S2 supplied to the storage container 11 and a time when the batch is supplied to the storage container 11. The control device 17 controls the timing of opening the gate 14 so that each batch is discharged from the storage container 11 immediately after staying in the storage container 11 for a predetermined time. As a result, the semi-molten slag particles S2 can be retained inside the storage container 11 for a predetermined time. The control device 17 has a timer for measuring the predetermined time. The supply of the semi-molten slag particles S2 and the opening and closing of the gate 14 can also be performed manually.

The semi-molten slag particles S2 supplied to the storage container 11 stay inside the storage container 11 for a predetermined time and are gradually cooled. In the present embodiment, the semi-molten slag particles S2 are slowly cooled from about 1300 ° C. to about 1100 ° C. over about 20 to 30 minutes. Although temperature control is not performed inside the storage container 11 (that is, the semi-molten slag particles S2 are slowly cooled by natural cooling), the heater and heat exchange are performed so that the particles are discharged at about 1100 ° C. after a lapse of a predetermined time. It is also possible to provide a temperature control device such as a container. By retaining and holding the semi-molten slag particles S2 in a high temperature environment of about 1300 to 1100 ° C. and aging and curing them, the formation and growth of pores of the semi-molten slag particles S2, that is, the size, number, shape, etc. of the pores are controlled. Can be done.

The semi-molten slag particles S2 that have been slowly cooled to about 1100 ° C. are discharged from the discharge port 13 of the storage container 11. The discharged particles are cooled to room temperature by a cooler (not shown) in the cooling step P1. It is considered that the cooling rate in the cooler does not significantly affect the characteristics of the slag material. This is because the size, number, shape, etc. of the pores are almost determined by the cooling process from about 1300 ° C to about 1100 ° C. _{Crystallization of SiO 2} , which accounts for more than half of the slag component, begins at about 1300 ° C ( _{the nuclei of SiO 2} are generated), and when cooled to about 1100 ° C, the structure of particles and pores is almost determined, and after that, the structure of the particles and pores is almost determined. The cooling process does not appear to have a significant effect on the structure of particles and pores. The cooled particles are lightly crushed and further sized (light crushing / sizing step P2). The outer shell of the particles may have an amorphous and fragile structure due to the rapid cooling _{of the SiO 2 component inside the wind crusher 2.} Further, many semi-molten slag particles S2 become substantially spherical during flight inside the wind crusher 2, but semi-molten slag particles S2 that cannot ride on the wind fall during flight and have a flat shape or an irregular shape. There is also something that becomes. Some particles coalesce inside the wind crusher 2 and the storage container 11 to form an irregular shape. The light crushing / sizing step P2 is performed not for the purpose of crushing particles but for the purpose of surface polishing of particles, removal of fragile tissues, and shaping. Further, the particles are separated by a vibrating sieve (not shown) (separation step P3), and only particles having a particle size of less than 5.0 mm are taken out as a slag material. The slag particles are classified by a vibrating sieve into particles having a particle size of 18 mm or more and 5 to 18 mm or less than 5 mm. In one example, from a semi-molten slag having a particle size of 150 t / h, slag having a particle size of 18 mm or more is produced at 35 t / h, slag having a particle size of 5 to 18 mm is produced at 35 t / h, and slag having a particle size of less than 5 mm is produced at 60 t / h.

The slag material formed by the above process has generally spherical open pores (pores that open on the surface of the particles, also called open pores) and approximately spherical closed pores (closed that are not connected to the surface of the particles). It is a pore and is also called a closed pore), and a capillary pore (capillary pore) is formed. The capillary pores are formed by the cooling high-pressure air or the like remaining inside the semi-molten slag particles S2 spreading in a mesh pattern to a portion having low viscosity. Some of the closed pores formed near the surface of the slag material are connected to the surface of the slag material via capillary pores. The open and closed pores are mainly formed by entraining air when the high temperature and low viscosity FeNi slag S1 flies in the air flow. Therefore, many closed pores are formed relatively close to the surface of the semi-molten slag particles S2. The amount and size of the closed pores and the open pores are the temperature of the FeNi slag S1 when supplied to the wind crusher 2, the flight distance of the FeNi slag S1, the supply amount of the FeNi slag S1, and the ratio between the wind speed and the air volume of the high-pressure air. It can be controlled by such as.

Further, by holding the semi-molten slag particles S2 in a temperature range of about 1300 to about 1100 ° C. for a predetermined time, the entrained air moves in the internal space of the semi-molten slag particles S2 in the semi-molten state, coalesces, and compares. It becomes a large (coarse) void (pore). The open and closed pores formed in this way have a high water retention function and efficiently release the retained water during the hydration reaction. In concrete and mortar, self-shrinkage occurs due to the loss of water during the hydration reaction, but the slag material produced in the present embodiment efficiently releases water during the hydration reaction and concrete. And suppresses self-contraction of mortar.

In general, fine aggregates used for concrete and mortar have a dense structure, a high absolute dry (surface dry) density, and a low water absorption rate, as specified in "JIS A 5011" in the relevant field. Materials with a large unit volume mass and actual volume ratio are considered to be high quality materials. On the other hand, by using a fine aggregate with a coarse void structure and a large water absorption rate, the strength after hardening is increased and self-shrinkage is suppressed while ensuring the fluidity during kneading and casting of concrete and mortar. It is also reported that it is possible. Regardless of whether the fine aggregate is a natural material or a slag material, the quality of concrete and mortar hardened after production deteriorates (shrinkage, cracks) due to the quality characteristics (performance physical characteristics, particle shape) of the fine aggregate. And so on). The slag material obtained in the present embodiment has a coarse void structure and a large water absorption rate, and concrete and mortar using this as a fine aggregate have high fluidity, strength, static elastic modulus, and small self-shrinkage.

In this embodiment, it is possible to manufacture a fine aggregate that exhibits the required performance according to the purpose of use. That is, it is possible to control the density, water absorption rate, actual volume rate, etc., which are typical indicators of aggregate quality, to the quality suitable for the purpose. For example, if the wind speed of the high-pressure air supplied to the wind crusher 2 is increased, the entire particles are cooled so as to be substantially crystallized in the wind crusher 2, and a slag material having small pores and a dense structure can be obtained. By reducing the wind speed of the high-pressure air supplied to the wind crusher 2, the particles can be coarsened, the cooling rate of the particles can be reduced, and the semi-molten slag particles S2 can be obtained.

Further, the above-mentioned slag material can be obtained by aging and curing the semi-molten slag particles S2 at a high temperature for a predetermined time. On the other hand, when the residence time of the semi-molten slag particles S2 inside the storage container 11 is shortened or substantially zero, the semi-molten slag particles S2 are rapidly cooled in the cooling process on the downstream side without being aged and cured. In this case, it is considered that a slag material in which a large number of relatively small pores are distributed can be obtained without coarsening the pores. Therefore, once the semi-molten slag particles S2 are produced from the FeNi slag S1, a slag material having various characteristics can be obtained according to the subsequent processing. The characteristics of the slag material can be variously changed by adjusting the time for the semi-molten slag particles S2 to stay inside the storage container 11. The temperature range for holding the semi-molten slag particles S2 is not limited to the range of 1300 ° C. to 1100 ° C., and may be a predetermined temperature range exceeding normal temperature (normal temperature is, for example, about 25 ° C.). For example, if the temperature at which the semi-molten slag particles S2 are discharged from the discharge port 13 of the storage container 11 is lower than 1100 ° C., more pores may grow and more coarse pores may be obtained. The temperature at the time of discharging the semi-molten slag particles S2 can be easily controlled by adjusting the residence time. As described above, the residence time of the slag particles S2 can be easily adjusted by the control device 17, so that the slag material manufacturing device 1 is not significantly affected.

Although some preferred embodiments of the present invention have been shown and described in detail, it should be understood that various modifications and modifications can be made without departing from the spirit or scope of the appended claims.

1 Slag material manufacturing equipment 2 Wind crusher 6 Collision plate 9 Container 11 Storage container 12 Supply port 13 Discharge port 14 Gate 15 First drive device 16 Second drive device 17 Control device S1 FeNi slag S2 Semi-molten slag particles

Claims (10)

1. By granulating and cooling the molten slag, the outside is condensed and solidified to form an outer shell, and the inside is partially condensed and solidified to form semi-molten slag particles.
   A method for producing a slag material, which comprises cooling the semi-molten slag particles.
2. The production method according to claim 1, wherein the semi-molten slag particles are held in a predetermined temperature range exceeding room temperature for a predetermined time before cooling.
3. The manufacturing method according to claim 2, wherein the predetermined temperature range is a temperature of 1100 ° C. or higher and 1300 ° C. or lower.
4. The manufacturing method according to claim 3, wherein the predetermined time is 20 minutes or more and 30 minutes or less.
5. The production method according to any one of claims 2 to 4, wherein the semi-molten slag particles are held inside the storage container for the predetermined time.
6. The production method according to any one of claims 1 to 5, wherein the semi-molten slag particles are formed by flying the molten slag with an air stream.
7. Any one of claims 1 to 6, wherein the slag particles obtained by cooling the semi-molten slag particles are lightly crushed, sized, and separated, and the slag particles having a predetermined particle size or smaller are taken out as a slag material. The manufacturing method described in the section.
8. The production method according to any one of claims 1 to 7, wherein the molten slag is a ferronickel slag in a molten state.
9. By granulating and cooling the molten slag, the outside is condensed and solidified to form an outer shell, and the inside is partially condensed and solidified to form semi-molten slag particles.
   A holding means for holding the semi-molten slag particles in a predetermined temperature range exceeding room temperature for a predetermined time, and
   An apparatus for producing a slag material, comprising a cooling means for cooling the semi-molten slag particles held for a predetermined time.
10. A container that supplies the semi-molten slag particles to the holding means,
    A gate for discharging the semi-molten slag particles from the holding means, and
    The manufacturing apparatus according to claim 9, further comprising a control unit that opens the gate after the predetermined time has elapsed since the semi-molten slag particles were supplied to the holding means.
    

Images