JP4367330B2 - Fused granulator for molten slag - Google Patents

Description

The present invention relates to Feng grinding apparatus for solidifying high basicity slag generated in the steel manufacturing process, for example steel slag, electric furnace slag, stainless steel slag and waste molten slag, spherical granules from a molten state, In this case, elution of chromium oxide can be prevented.

  The air crushing technology for obtaining spherical particles from molten slag using a gas body such as air and the water crushing technology for obtaining sand-like particles from molten slag using a large amount of water are well known, and the crushing technology depends on the properties of the target slag. And water granulation technology.

  Of these, water granulation requires strict management against water leakage and drought leakage, and complicated equipment maintenance management such as corrosion and wear. In addition, the resulting product has many pores and needle-like projections, so it becomes porous and soft, and in order to use it as a substitute for natural sand, it is necessary to chamfer, reduce pores, and increase the unit volume mass. is there. In addition, the molten slag discharged from batch processing melting furnaces such as converters and electric furnaces is once transported to a processing plant after being put in a pan, which may cause a steam explosion when the pan is discharged abnormally. .

  On the other hand, when a large amount of air crushing is performed, the equipment area and the amount of air consumed are enormous. In addition, when high basicity stainless steel slag is crushed, it may be pulverized within a few days even if granulated, so high basicity stainless steel slag cannot be reused as a high value-added product, There was no other but to landfill. In addition, only air crushing has a problem that chromium oxide is eluted, and it is necessary to perform an elution prevention treatment.

  In addition, artificial stone materials manufactured using slag with artificially adjusted colors such as blue, green, black, and warm colors are low bases of about 0.85 to 1.3 with the addition of additives. And extra additives were required.

Among these problems, regarding the prevention of pulverization by wind crushing, in Patent Document 1, the blast furnace slag is air crushed and recovered with a rotating drum, and the vitrification rate is adjusted with a heat retaining tank, whereby a cement raw material is obtained. There has been proposed a technique capable of separately producing a glassy slag grain suitable for use and a crystalline slag grain suitable for sand substitution.
JP-A-11-236609

In Patent Document 2, after steel mill slag is crushed to a particle size of 2.5 mm or less, a predetermined amount of water is added and kneaded to be pressed into a predetermined shape, and then cured by a carbonation reaction. A technology has been proposed for making black particles containing a large amount of iron to prevent pulverization.
JP 58-74559 A

In addition, regarding the method of receiving particles by air crushing, in Patent Document 3, glassy material containing [B], [SiO ₂ ] and the like is added to molten slag, followed by air crushing, and flowing the air crushed particles. The technology received on the inclined plate is proposed.
JP 2003-155511 A

For preventing elution of hexavalent chromium (Cr ⁺⁶ ) from stainless steel slag, for example, in Patent Document 4, sprinkling and immersing the chromium-containing material using a blast furnace slow-cooled slag cooling wastewater containing sulfur of +5 or less. Thus, a method has been proposed in which Cr ⁺⁶ is reduced to trivalent chromium (Cr ⁺³ ) by contacting them to prevent elution.
JP 2002-248444 A

In addition, regarding obtaining blue and green artificial sand from high basicity slag, Patent Document 5 discloses that feldspar and lime so that the basicity (CaO / SiO ₂ ) is 0.85 to 1.2 in blast furnace slag. In addition, a method of adding cobalt oxide to remelt and cooling to obtain a blue artificial stone material, and a method of adding chromium oxide to obtain a green artificial stone material are disclosed.
JP-A-8-91884

However, the air crushing technique proposed in Patent Document 1 is directed to blast furnace slag having a low basicity with a basicity (CaO / SiO ₂ ) of less than 1.3. Therefore, it is difficult to vitrify a high basicity slag having a basicity of 1.3 or more, and it is still possible to avoid the collapse after solidification by only air crushing.

Moreover, in the wind-pulverization technique described in Patent Document 2, the components of the steel-making wind-pulverized slag described as examples are CaO / SiO ₂ = 3.83 to 6.28, MgO = 3.44 to 5.85. In particular, there is no description of examples using stainless steel slag containing almost no FeO and Fe ₂ O ₃ and containing 6% by mass or more of MgO. Therefore, it is not clear whether powdering can be prevented when such stainless steel slag is used.

  In addition, the air crushing technique proposed in Patent Document 3 requires an extra slag modifier and a facility for providing a water flow on the inclined plate.

Moreover, although the technique proposed in Patent Document 4 is described as being able to prevent elution of Cr ⁺⁶ from stainless steel slag, it is a sulfur-containing aqueous solution simultaneously with air that is crushed against molten slag containing chromium. Or if blast furnace granulated by blowing blast furnace slow cooling slag cooling wastewater, or if chrome-containing slag is blown by water and then immersed or sprinkled in blast furnace slow cooled slag cooling wastewater, is it possible to prevent elution of Cr ⁺⁶ ? It is unknown. In the technique proposed in Patent Document 4, it takes 3 to 7 days to obtain a product, the reaction time is long, and a large site area is required.

  Thus, in the past, high basicity slag has a high melting point and it is too expensive to remelt, and it is difficult to maintain the stone shape due to pulverization and collapse. Could not be crushed. Therefore, a technique for making artificial stone materials by lowering the melting point, lowering the melting point, adding additives, and then re-melting has been the mainstream.

Further, as disclosed in Patent Document 5, a technique for artificially coloring is disclosed, but a high-melting-point stainless steel reduction stage having a high basicity of CaO / SiO ₂ of 1.3 or higher and a melting point of 1500 ° C. or higher. Green artificial sand could not be made directly from slag.

The problem to be solved by the present invention is that in the case of high-basicity slag with CaO / SiO ₂ of 1.3 or more, pulverization cannot be prevented and the obtained spherical particles of The Cr ⁺⁶ elution prevention treatment cannot be performed in a short time, and further, there is a problem that green artificial sand cannot be directly produced.

The melt slag wind granulation apparatus of the present invention,
A U-shaped ridge that once receives a slag flow that flows down vertically, guides it downward, and flows down vertically as a film from the tip;
A nozzle for spraying water droplets and an air flow or an inert gas flow against the film-like molten molten slag at a position where the flowing distance of the molten slag flowing in the film form is 200 mm or more and within 1 m;
An inclined wall surface disposed in a range of 3 to 10 m from the front-side feng shui point where the fractured spherical particles fly by the collision between the water droplet and the air flow or inert gas flow;
It is equipped with a product pit or a carry-out conveyor that collects and collects Feng Shui spherical particles rolling and falling on this inclined wall,
The nozzle is sprayed with water in advance inside the air ejection nozzle, it is the most important feature configuration der Rukoto blown in a state of being mixed with the air stream and water droplets at the nozzle discharge port.

Then, using the molten slag containing fraud and mitigating risk chromium component to the book onset Akira,
The resulting Feng crushed spherical particles,
Or immersed in an aqueous solution containing less than +5 valence sulfur or blast furnace slag cooling drainage containing +5 valence or less sulfur within 24 hours,
Or
Water droplets that mix with an air stream or an inert gas stream sprayed onto the molten slag,
It is an aqueous solution containing +5 or less valent sulfur, or cooling drainage of blast furnace chilled slag containing +5 or less valent sulfur,
Or
If you apply both of these,
Spherical Fractured and Granulated Particles that suppress Cr ⁺⁶ elution as much as possible can be obtained.

Lever to use the device according to the present invention, the high basicity slag can advantageously be solidified spherical particles. And when the high basicity slag is stainless steel, Cr ⁺⁶ elution can be prevented, and the slag directly has a green color without adjusting and remelting the slag components as before. Particles can be obtained.

The particles obtained by the device of the present invention can be used as a substitute for sand, and since there is almost no powder, green materials with good scenery such as water-permeable and drainable pavement materials, sidewalks such as parks and general roads, etc. Paving is possible. The block can be used as a green aggregate such as a sidewalk interlocking block or tile.

  In addition, since the apparatus of the present invention can significantly reduce the necessary air volume as compared with conventional air crushing, the apparatus can be downsized and the power consumption of the blower and the like can be reduced. In addition, since the flying of the granulated particles can be shortened to the minimum, the collection device can also be miniaturized.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings along with the progress from the new idea of the present invention to the solution of a problem.

(About new ideas)
High basicity slag, such as stainless steel slag, (A) Keeps the particle shape while maintaining the strength to withstand reuse of sand substitutes without being powdered, and (B) Cr ⁺⁶ harmful substances elute The inventors have obtained the following idea about not performing (C) that can be processed with as little energy as possible.

(A) About maintaining particle shape while having strength that can withstand reuse such as sand substitution without pulverization Dicalcium silicate (2CaO.SiO ₂ ) is from α-type phase (specific gravity 3.07) at 2130 ° C. Phase transition to α′-type phase (specific gravity 3.31) at 1450 ° C., and further to γ-type phase (specific gravity 2.97) at 850 ° C. or β-type (specific gravity 3.28) at 675 ° C. It is widely known that it undergoes a cooling process while undergoing a change involving expansion.

  Therefore, the inventors thought that the collapse can be prevented by rapid cooling so as not to cause volume expansion in the cooling process after solidification. And, without using slag modifier, high basicity slag is not pulverized, and in order to continue to maintain the particle shape, it is necessary to quench rapidly without using a large amount of water, We considered using a mist spray of water in combination with air crushing.

  When the inventors disperse the molten slag of high basicity into as fine droplets as possible and quench it with air and water mist, the particles can be made dense, few pores, heavy, and high in particle crushing strength. Thought. In addition, it was considered that such particles are stable because oxygen, carbon dioxide gas, moisture, and other gases in an outside atmosphere in contact with the particles are difficult to enter.

Harmful substances (B) Cr ⁺⁶ to shorten the reduction time of Cr ⁺⁶ for not elute, (b1) that the reaction required amount of Cr ⁺⁶ is small, the Cr ⁺⁶ to be (b2) reducing It is important to satisfy the conditions such as being in a state of being easily reacted and (b3) that the reducing agent is sufficiently present, and it is clear that the reaction is completed instantaneously if the conditions are satisfied.

Here, among the above conditions, the state in which Cr ⁺⁶ to be reduced in (b2) easily reacts is that the eluted Cr ⁺⁶ exists only on the particle surface. In this case, the reaction is instantaneous. However, if Cr ⁺⁶ elutes from the inside, the elution rate becomes the rate-determining rate, which makes the reaction difficult and takes time for the reaction.

Moreover, in order to reduce the reaction required amount of Cr ⁺⁶ which is the condition of (b1), it is considered that air crushing that can reduce the surface area per unit weight is good. Pulverized particles are characterized by the fact that molten slag is dispersed into droplets and solidifies, so that particles close to powder do not exist due to the effect of surface tension, and the specific surface area is small. In the case of water granulation, due to cooling crushing with water, the structure has pores inside the particles, and the needle-like projections are broken into powder in the subsequent steps such as conveyance and sieving, and the specific surface area increases.

Regarding the prevention of elution of Cr ⁺⁶ present in high basicity slag such as stainless steel slag, at first, in the case of crushed particles, it was thought that the surface would be amorphous glassy, so it would not elute. As a result, Cr ⁺⁶ was eluted.

This is presumably because Cr ⁺⁶ is present only on the surface of the particles in the wind and water granulated particles, and water and water vapor are present around the particles at the time of the wind and water granulation, so that the particles are easily eluted. Therefore, when the technique described in Patent Document 4 was applied and immersed in a blast furnace slow-cooled slag cooling wastewater containing sulfur having a valence of +5 or less, the reduction reaction of Cr ⁺⁶ was considered to be completed instantaneously. Furthermore, if blast furnace slag cooling effluent was used as the water used for wind granulation, it was thought that Cr ⁺⁶ could be reduced simultaneously with the wind granulation.

(C) About being able to process with as little energy as possible When considering as an actual operation facility, downsizing of the equipment is indispensable to arrange it near the furnace of an existing stainless steel factory, Miniaturization is important. To that end, it was considered necessary to shorten the flight distance of particles. Further, regarding the flue gas air volume, since the evaporation latent heat of water is used in the wind-and-water granulation, it can be reduced to 1/5 to 1/7 compared with the case of air-only crushing, and the apparatus can be remarkably reduced.

  Moreover, in order to stably obtain a uniform product, it is necessary to prevent generation of particles having a low cooling rate. To that end, it was considered effective to apply the slug flow to the trough once, spread it thinly and apply it uniformly to the water droplets and the air flow.

(Progress from idea to problem solving)
The inventors experimented whether or not the particles would be stable without collapsing when high basicity slag having CaO / SiO ₂ of 1.3 or more was blown. As a result, the recovered slag was able to obtain spherical particles having a green color, but most of them were pulverized after 3 days.

  When the crystal structure of the powdered slag was investigated, the crystal structure was found to be γ-type, and was the same as the decay process by the usual phase transformation. However, it was presumed that the particle strength was improved and the collapse was delayed because of the rapid cooling during granulation. In the case of air crushing, energy is concentrated to disperse the molten slag into fine droplets, and the cooling is performed during the flight with the gas used for dispersion, so the cooling position is wide and long. It was slow cooling.

  Therefore, in order to further improve the cooling rate, water spray was applied simultaneously with the compressed air to the crushed point of the molten slag, and the latent heat of vaporization of water was used. The cooling mode of this wind-and-water granulation is characterized in that the molten slag is dispersed into droplets and simultaneously comes into contact with the water droplets to concentrate the cooling energy due to the latent heat of vaporization of water. As a result of applying this wind-and-water granulation, green spherical particles did not collapse, and particles that did not pulverize after 6 months could be obtained.

  Further, as a result of microscopic analysis, it was found that it had an α'-type crystal structure and was not pulverized. At the same time as the analysis of the crystal structure, the vitrification rate was measured with a microscope, but the vitrification rate was 0% by the measurement method, and it was not vitrified even by wind-and-water granulation with improved cooling capacity compared to conventional wind-pulverization. I found out. Moreover, the particle size was as coarse as 1 to 5 mm, and it was confirmed that the larger the particles, the easier the collapse.

Next, as a result of an elution test of this wind-and-water granulated slag, Cr ⁺⁶ was eluted. Therefore, in order to prevent Cr ⁺⁶ elution from this granulated slag, the elution test was conducted by immersing it in blast furnace chilled slag cooling wastewater containing sulfur of +5 or less valence for 24 hours. As a result, the quantitation limit was 0.02 mg / liter or less, and Cr ⁺⁶ was not detected.

According to the conventional knowledge, since the reaction time of 3 days or more was required only by immersing the chromium oxide-containing slag in an aqueous solution containing sulfur having a valence of +5 or less, this granulated slag was formed from the surface of the Cr ^{+ 6} is likely to elute, and Cr ⁺⁶ is considered to exist only on the surface.

Further, as a result of the dissolution test conducted by changing the immersion time to 1 minute, 1 hour, 10 hours, and 24 hours with respect to the reaction time, as shown in FIG. 6, the reaction was almost completed in the initial 1 minute. 0.023 mg / L after 1 hour, 0.024 mg / L after 10 hours, and 0.020 mg / L or less after 10 hours, indicating that Cr ⁺⁶ elution can be prevented by an instantaneous reaction.

Further, when only the inside of the particles was taken out and pulverized, and then an elution test was performed, chromium was not hexavalent and did not elute inside the particles. This is a process in which the granulated particles are dispersed from the molten state into fine droplets and rapidly cooled and solidified, and a chromium component (CaCr ₂ O ₄₎ that was originally in a trivalent oxidation state by a substance present around the particle, for example, oxygen. This is because only the surface becomes a hexavalent oxidation state (CaCrO ₄ ).

On the other hand, the inside of the particle is dense with the rapidly cooled and solidified spherical granulated particles, so that oxygen in the external atmosphere cannot enter the inside, and the chromium component in the particle remains in the trivalent oxidation state (CaCr ₂ O ₄ ). This is because it exists. Furthermore, it was found that even when the inside of the particle comes into contact with oxygen in the atmosphere at room temperature, it is already trivalent and stable, so it does not become hexavalent and does not elute.

Furthermore, the same effect was acquired when the cooling waste water of the blast furnace slag annealing process containing sulfur of +5 valence or less was used as water sprayed simultaneously with air at the time of wind-and-water granulation. The untreated slag had a dissolution of about 0.1 mg / liter of Cr ⁺⁶ , whereas the result was about 0.05 mg / liter.

  This is considered to be due to the fact that the sulfur concentration in the blast furnace slow-cooled slag cooling water was fluctuated or oxidized at a high temperature, and the contained sulfur was burned off and the effect was reduced. For combustion, if the gas to be crushed is an inert gas such as nitrogen, the effect can be easily estimated.

  In addition, the nozzle was improved to make the particles finer in order to increase the cooling rate. In the improvement, water was sprayed in a jet of crushed air, water droplets were uniformly dispersed in the jet, and the jet was applied to the molten slag. As a result, the dispersion force and evaporation latent heat due to gasification of water spread over all the slag, and fine particles having an average particle diameter of 1 to 2 mm were obtained.

  In order to stably obtain a uniform product, the issue is how to efficiently apply the slag flow to the air and water droplet spray flow. The inventors have found that the molten slag that flows down vertically is flowing in a columnar shape due to surface tension even if it is thinly spread from the upper container and discharged, and spreads thinly just above the air or water droplet spray flow. Otherwise, it was found that uniformity could not be maintained when colliding with air or water droplet spray flow.

  Further, it was found that the outer periphery of the molten slag cylindrical flow is finely dispersed, but the central portion is insufficiently dispersed in both the dispersion force and the cooling capacity, resulting in inefficient wind and water granulation. Therefore, as a countermeasure, the slag flow is widened by interposing a U-shaped cross-section so that the air flow and the water droplet spray flow can collide uniformly. As a result, most of the slag was uniformly dispersed, and there was almost no dripping slag.

  In order to make the equipment compact, an inclined plate is placed facing the Feng Shui crushing unit and at a short distance from the fracturing point, and the Feng Shui flue gas hood and granule are placed on the inclined plate. A test was conducted to determine the flight distance that allows the recovered slag to maintain a spherical shape by colliding the crushed particles. When there is no inclined plate, it flies about 20 m, but the spherical shape was maintained even when the installation position of the inclined plate was reduced to 12 m and 10 m and approached to a position of 5 m.

  From this, it was found that in the device design, the inclined plate may be brought close to 5 m from the wind breaking point, and the device can be miniaturized.

  In addition, the accumulation device can be made unnecessary by using an inclined or vertical wall so that the impacted granulated particles can roll and fall under their own weight. This result is possible because the molten slag is dispersed into the droplets, and air and water are sprayed at the same time, and strong cooling is performed simultaneously with the dispersion.

In addition, if the exhaust gas flow rate is to take away the latent heat of vaporization of water with sensible heat of air, an air amount of about 25 Nm ³ is required instead of 1 kg of added water, which requires enormous equipment and operating costs. If the latent heat of vaporization of water is used, it is possible to achieve the same equipment cost and operation cost as in the case of conventional wind crushing.

The apparatus for wind and water granulation of molten slag according to the present invention has been made based on the above findings and the results of various investigations based on these findings,
A U-shaped ridge that once receives a slag flow that flows down vertically, guides it downward, and flows down vertically as a film from the tip;
A nozzle for spraying water droplets and an air flow or an inert gas flow against the film-like molten molten slag at a position where the flowing distance of the molten slag flowing in the film form is 200 mm or more and within 1 m;
An inclined wall surface disposed in a range of 3 to 10 m from the front-side feng shui point where the fractured spherical particles fly by the collision between the water droplet and the air flow or inert gas flow;
It is equipped with a product pit or a carry-out conveyor that collects and collects Feng Shui spherical particles rolling and falling on this inclined wall,
The nozzle is to spray the water in advance inside the air ejection nozzle, characterized by configuration der Rukoto blown in a state of being mixed with the air stream and water droplets at the nozzle discharge port.

Molten slag to be applied to Feng grinding apparatus for molten slag of the present invention, the component range of that, CaO: 60 wt% or less, SiO _2: 5% by mass or more, and basicity (CaO / SiO ₂₎ is It is desirable to set it as 1.3-6.0.

The reason for this is that the constraints on the high basicity side are such that the CaO content is 60% by mass or less and the basicity (CaO / SiO ₂ ) is 6.0 or less under the conditions exceeding 6.0. This is because there is no such knowledge. On the other hand, the reason why the basicity (CaO / SiO ₂ ) is set to 1.3 or more is that the basicity (CaO / SiO ₂ ) is less than 1.3, so that the basic pulverization does not cause pulverization. However, it goes without saying that the wind granulation technique of the present invention is also applicable to low basicity slag of 1.3 or less.

Moreover, in this invention, there is no restriction | limiting in the iron content of the molten slag to apply . This is because slag containing a large amount of iron is not easily pulverized even if the basicity is high, and can be easily applied. It can be applied to blast furnace slag, converter slag, electric furnace slag, waste molten slag, and the like.

Then, in the present invention, a form Ru collide water droplets and air flow to the molten slag, a method of colliding a molten slag becomes 2 laminar flow parallel adjacent spray flow and the air flow of the water droplet, the air flow There is a method in which water droplets are sprayed and collide with the molten slag in a state where the water droplets are dispersed in the air flow, but any method may be adopted in the present invention.

  In addition, water droplets and airflows may collide with the flow of molten slag at any angle, but the waterdrops and airflow are most efficiently collided with the slag flow at an injection angle suitable for each arrangement. It is desirable to adjust the angle at which the slag droplets are dispersed.

The Feng Shui grinding apparatus for molten slag of the present invention, the use of molten slag containing chromium component, as in the prior art without remelting by adjusting the slag component directly to obtain a green spherical particles it can.

Further, in the present invention, spherical particles obtained by subjecting molten slag containing a chromium component to air-water crushing are added to a sulfur-containing aqueous solution having a valence of +5 or less, or into a blast furnace gradually cooled slag cooling wastewater containing sulfur having a valence of +5 or less. If immersed within, Cr ⁺⁶ present on the surface of the spherical particles can be effectively reduced. Here, the immersion time is set to be within 24 hours in order to ensure certainty during product processing, but in fact, the reaction can be instantaneously completed as a granulated particle.

Further, in the present invention, as water droplets to be blown onto the molten slag and mixed with the air flow, an aqueous solution containing sulfur of +5 valence or less, or cooling effluent of a blast furnace chilled slag containing sulfur of +5 valence or less, Reduction of Cr ⁺⁶ can be performed more effectively.

  Further, in the present invention, as shown in FIG. 1, the slug flow 1 flowing down vertically is inclined at an angle θ1 of 45 ° to 80 °, for example, and has a U-shaped cross section. 2, with respect to the film-like molten molten slag 1 ′, for example, upward so that the flowing distance of the molten slag 1 ′ flowing down into the film shape from the tip of the trough 2 is 200 mm or more and within 1 m. It is desirable that the water droplets blown from the angle θ2 of 30 ° collide with the air flow 3.

  The reason for this is that the slag flow 1 flowing down vertically is received by a slanted trough 2 and spreads thinly, and then a water drop and an air flow 3 are applied to the film-like molten slag 1 ′. This is because the load of the molten slag can be made uniform with respect to the width direction of the water droplets and the air flow 3.

In this case, if the flow distance of the molten slag flowing down from the tip of the soot is less than 200 mm, solidified growth from the tip of the soot reaches the slag jet, and the molten slag and the jet do not collide stably. On the other hand, if it exceeds 1 m, the free fall speed increases, and a product that breaks through the jet and is not fractured is generated. In addition, the molten slag spread thinly in the width direction starts to be reassembled due to surface tension and does not flow down into a film shape, and slag that penetrates the jet and is not crushed is generated. Therefore, falling distance of the molten slag in the present invention, are within the 1m above 200 mm.

  In the present invention, the slag flow that flows downward in the vertical direction is received by the U-shaped ridge in the case of a flat ridge, because the slag solidifies around the border where the flow rate of the molten slag is small, This is because the falling position of the slag changes and stable fracturing cannot be obtained.

  The flow direction of the molten slag guided by the scissors can be arbitrarily arranged, such as a flow direction in the jet discharge direction, a flow direction in the opposite direction, or a perpendicular direction. At this time, in the case of vertically downward, air and water droplet jets are uniformly blown from the circumference to the cylindrical slag flow, whereby uniform particles can be obtained.

If the molten slag containing the chromium component is subjected to wind-and-water granulation by the above-mentioned apparatus of the present invention, Cr is instantaneously added to the aqueous solution containing sulfur having a valence of +5 or less or in the cooling effluent of a blast furnace annealing cooled slag containing sulfur having a valence of +5 or less. ^Since the elution of ⁺⁶ is completed and the reduction reaction is completed, spherical wind granulated particles having an elution value of Cr ⁺⁶ of 0.04 mg / liter or less can be obtained within 1 hour. Then, as shown in FIG. 4, for example, when the particle size is 1 mm, the obtained spherical wind granulated particles are 294N or more green particles stronger than the crushing strength (48.9N) of sea sand. there were. FIG. 4 also shows the crushing strength of blast furnace water granulation.

Moreover, in this invention apparatus, as shown in FIG. 2, the inclined wall surface 6 is set in the range of 3-10 m from the front-side Feng Shui crushing point where the Feng Shui particle 5 flies by the collision of the water droplet and the air flow 3. arrangement, and Feng ground particles 5 that roll falls by its own weight to the inclined wall surface 6 for example to collecting recovered in product pits 7.

  Conventionally, a long hood of about 20m from the air crushing point and a carry-out conveyor are arranged at the bottom of the hood, but in the present invention, a short hood can be used based on the result of the short-distance collection test using the inclined wall surface described above. It is possible to gather at the lower accumulation place by inclining so as to roll with its own weight. In addition, after gathering, you may carry out with a conveyor.

Further , as shown in FIG. 1, the film-like molten melt flows at a position where the flow distance of the molten slag 1 ′ flowing in a film form from the tip of the ridge 2 having a U-shaped cross section is 200 mm or more and within 1 m. to slug 1 ', place the nozzle 4 for spraying so impinging homogeneously mixed water droplets and the air flow 3. The nozzle 4 includes an air header 4a for blowing an air flow, and a spray nozzle 4b for spraying water in advance in the air header 4a so as to blow in a state where water droplets are mixed in the air flow blown from the air header 4a. It is composed of

  If such a nozzle 4 is employ | adopted, the dispersion | variation in the cooling rate of a granulated particle can be reduced. Needless to say, if the variation in cooling rate does not become a problem, the air or gas nozzle and the water spray nozzle may be overlapped to form a two-layer flow and collide with the feng shattering point. .

Hereinafter, the results of experiments conducted to confirm the effects of the present invention will be described.
Table 1 below shows the components of the stainless steel slag used for wind-and-water granulation. This slag is a slag that gradually collapses from the cold surface when gradually cooled, and finally powders into a white powder of about 40 μm or less.

The slag discharged from the ladle 9 by the apparatus shown in FIG. 1 was once taken out quantitatively from the nozzle hole through the intermediate pot, and was crushed by wind and water there. The slag flow rate was 30 tons / hour, the slag temperature was 1600 ° C., the crushed air flow rate was 30 m ³ / minute, the pressure was 2000 mmAq, and the amount of sprayed water in the water droplets was 2 to 10 tons / hour.

  The width of the nozzle used for the wind and water granulation was 150 to 200 mm in width and 40 to 80 mm in length, and a jet was formed at an angle of 0 to 30 ° from the horizontal to the upper side. The molten slag flowing vertically downward from above is temporarily tilted at 45 to 80 °, and the transverse cross section with a width of 150 to 300 mm is received with a U-shaped scissors, and the slag is thinly widened to 100 from the tip. It collided with a jet located below 400 mm.

  As a result, the particle size distribution of the obtained slag is shown in FIG.

The results of the dissolution test of Cr ⁺⁶ are shown in Table 2 below.
Case 1 is unprocessed only by Feng Shui, Case 2 is immersed in tap water for 24 hours, Case 3 is 24 hours of blast furnace chilled slag cooling drainage containing sulfur of +5 valence or less. When soaked, Case4 shows the results when blast furnace slag cooling drainage is used for water used for wind granulation.

In Case 1, Cr ⁺⁶ is clearly eluted, and it is necessary to prevent elution before reuse. Case 2 was immersed in tap water for a comparative test. Case 3 was 0.02 mg / liter or less, and Cr ⁺⁶ was reduced and was not eluted. Case 4 was not as effective as Case 3, but the elution of Cr ⁺⁶ was reduced to less than half.

The cause of this is due to fluctuations in the water quality of the blast furnace slow cooling slag cooling drainage shown in Table 3 below, and the amount of sulfur dissolved below +5 valence varies depending on the timing of drainage, watering, air cooling, etc. It is. It is also conceivable that the dissolved S burns in contact with the high-temperature soot and shifts into the exhaust gas, reducing the sulfur as the reducing agent. However, it has become clear that there is an effect in reducing Cr ⁺⁶ elution. The lower limit of the preferable content of S- ² ions is predicted to be about 100 ppm.

The result of comparing the crushing strength of the particles with blast furnace slag granulated particles and sea sand is shown in FIG. From FIG. 4, it can be seen that in the granulated particles produced using the apparatus of the present invention, the particles themselves are very hard and dense. Regarding the coloration, the blast furnace and converter slag are black, but the slag and granulated particles of stainless slag are green. The cross section is schematically shown in FIG. 5, and it was found that when the granulated particles 5 were broken, the inside 5b of the particles was gray and only the surface 5a was green.

Exhaust gas amount of Feng grinding, when a trial calculation in the embodiment shown in FIG. 1, the latent heat of vaporization of water 2 ton / time 1238Mcal / time, 22044Nm ³ / time when an attempt to concentrate the air commensurate therewith the molten slag dispersion point It becomes.

In order to supply this with the nozzle shown in FIG. 1, it is necessary to secure a discharge speed of 816 m / second, which is obviously not practical. Since water evaporates and becomes steam, the volume ratio of 2 tons / hour of water is 3346 m ³ / hour, and 22044/3346 = 6.6 times more exhaust gas is generated, which may increase the size of the exhaust equipment. it is obvious.

  The present invention is not limited to the above example, and it goes without saying that the embodiment may be appropriately changed within the scope of the technical idea described in each claim.

It is the schematic which showed the front | former stage structure of an example of this invention apparatus. Is a schematic view showing an example of the present invention device. It is the figure which showed the particle size distribution of the slag obtained by experiment. The crush strength of Feng crushed particles manufactured using the present invention apparatus is a diagram showing the results of a comparison blast furnace slag water ground particles, and sea sand. It is the figure which showed typically the cross section of the wind-and-water granulated particle of stainless steel slag. It is a figure which shows the elution value of the time immersed in sulfur containing water, and Cr ^{+ 6} .

Explanation of symbols

1 Slag flow 1 'Molten slag 2 ３ 3 Water droplets and air flow 4 Nozzle 4a Air header 4b Spray nozzle 5 Feng shatter particles 6 Inclined wall 7 Product pit 8 Product

Claims (6)

A U-shaped ridge that once receives a slag flow that flows down vertically, guides it downward, and flows down vertically as a film from the tip;
A nozzle for spraying water droplets and an air flow or an inert gas flow against the film-like molten molten slag at a position where the flowing distance of the molten slag flowing in the film form is 200 mm or more and within 1 m;
An inclined wall surface disposed in a range of 3 to 10 m from the front-side feng shui point where the fractured spherical particles fly by the collision between the water droplet and the air flow or inert gas flow;
It is equipped with a product pit or a carry-out conveyor that collects and collects Feng Shui spherical particles rolling and falling on this inclined wall,
The nozzle is sprayed with water in advance inside the air ejection nozzle, Feng grinding apparatus for molten slag, which is a structure which blows in a state of being mixed with the air stream and water droplets at the nozzle discharge port. Nozzles for spraying so as to collide against the molten slag obtained by the flow down the melt according to claim 1, characterized in that the water droplets and the air flow or inert gas flow, is shall collide simultaneously and in the same position Feng grinding apparatus of slag. The molten slag, CaO: 60 wt% or less, SiO _2: containing more than 5 wt%, and the basicity (CaO / SiO ₂₎ and the said der Rukoto those from 1.3 to 6.0 Feng grinding apparatus for molten slag according to claim 1 or 2. The molten slag, Feng grinding apparatus for molten slag according to claim 3, characterized in that containing chromium component. The facility further comprises a facility for immersing the Feng Shui spherical particles in a sulfur-containing aqueous solution having a valence of +5 or less or a blast furnace slow-cooled slag cooling wastewater containing sulfur of a valence of +5 or less within 24 hours. Feng grinding apparatus for molten slag according to any one of 1 to 4. Water droplets that mix with an air stream or an inert gas stream sprayed onto the molten slag,
It is the cooling wastewater of the aqueous solution containing + pentavalent or less sulfur, or the blast-furnace slow-cooled slag containing + pentavalent or less sulfur, The molten-slag wind granulation apparatus in any one of Claims 1-5 characterized by the above-mentioned.