System and method for preparing hollow glass microspheres from blast furnace slag

Abstract

The present invention discloses a system and method for preparing hollow glass microbeads from blast furnace slag, and belongs to the technical field of resource utilization of metallurgical solid waste. A mixed cooling medium integrated plate is located directly above the rotating cup, and is connected to the granulation chamber and fixed to the ground; the rotating cup is driven by a variable frequency drive motor, and a gas coolant nozzle and an atomized liquid coolant nozzle are evenly distributed on the mixed cooling medium integrated plate along the circumferential direction; the gas coolant nozzle and the atomized liquid coolant nozzle are horizontally moved along nozzle moving slide rails parallel to the radial direction of the rotating cup respectively; the gas coolant nozzle and the atomized liquid coolant nozzle spray direction are perpendicular to the horizontal plane of the rotating cup. The system adopts a mixed cooling medium to assist the centrifugal granulation of blast furnace slag, which can not only reduce the energy consumption of continuous operation of the rotating cup and save water, but also promote the secondary crushing and granulation of the slag film, improve the hollowness and glass phase of the granulated slag, and prepare hollow glass microbeads, which greatly improves the added value of the granulated slag.

Description

Technical Field

[0001] The invention belongs to the technical field of resource utilization of metallurgical solid waste, and specifically relates to a system and method for preparing hollow glass microspheres from blast furnace slag. Background Art

[0002] The treatment process of blast furnace slag is mainly divided into two categories: wet treatment and dry treatment. The wet treatment processes mainly include bottom filtration, Inba method, Lhasa method, Tula method, etc.; the dry treatment processes mainly include centrifugal granulation, wind quenching, steel ball quenching, drum method, etc. Domestic steel companies mostly use bottom filtration, and most foreign steel companies use Inba method. Both are wet treatment processes. Due to the characteristics of treatment process, chemical composition and mineral composition, blast furnace slag is mainly used for cement and building materials. However, this treatment process not only cannot recover high-temperature waste heat, but also has the disadvantages of consuming a large amount of fresh water and easily producing harmful gases, and the added value of the product is also relatively low.

[0003] Blast furnace slag dry granulation technology is an ideal way to recover sensible heat. At present, dry granulation methods are mainly divided into two categories: centrifugal granulation and gas quenching granulation. In comparison, the centrifugal granulation method has the advantages of simple and compact structure and low energy consumption, while the gas quenching granulation method has poor granulation effect and low cooling intensity. Regardless of the dry granulation technology, there are problems such as difficult to ensure product quality, low heat recovery efficiency and difficulty in continuous operation. At present, none of them has been industrialized.

[0004] Studies have shown that the better the granulation effect of the slag, the smaller the particle size, the higher the roundness, glass phase and heat recovery efficiency. At the same time, if the hollowness of the granulated slag can be improved and hollow glass microspheres can be prepared, it has broad prospects in the high value-added resource utilization of abrasives, architectural 3D printing, photocatalytic composite materials, etc. Therefore, using mixed cooling media to assist the centrifugal granulation of blast furnace slag, enhance the granulation effect, increase the hollowness and glass phase of granulated slag, effectively utilize the sensible heat of the slag, and significantly increase the added value of the product.

[0005] Preparation of hollow glass microspheres from blast furnace slag includes two aspects: granulation behavior and bubble behavior. Using a rotating cup for centrifugal granulation alone requires a high speed, high energy consumption, and limited granulation effect. Once the speed is reduced, a large number of slag blocks will be formed. During centrifugal granulation, the slag first forms a melt film on the upper surface of the rotating cup, and then the melt film is broken into slag particles. Therefore, the use of a gas coolant sprayed vertically downward can promote the secondary crushing of the melt film, enhance the granulation effect, and obtain slag beads with smaller particle size; at the same time, the melt film mainly relies on its own surface tension to shrink during the secondary crushing process to form round slag beads. Once it contacts the atomized droplets, it couples with the surface tension to promote the film contraction, and the droplets are instantly vaporized and thus coated in each slag bead, forming a certain degree of hollowness. By matching the rotating cup speed, the injection pressure of the gas coolant and the atomized liquid coolant, and the radial position of the gas coolant nozzle and the atomized liquid coolant nozzle, a high proportion of hollow glass microspheres can be prepared. On the basis of making full use of the sensible heat of the slag, the added value of the product can be effectively improved, and the green and sustainable development of the steel industry can be actively promoted. Summary of the invention

[0006] The purpose of the present invention is to use a mixed cooling medium to promote the secondary crushing and granulation of a melt film during a centrifugal granulation process, to prepare high-quality hollow glass microspheres, and to provide a method for regulating the hollowness and glass phase of centrifugal granulated blast furnace slag using a mixed cooling medium, so as to achieve the preparation of hollow glass microspheres, and effectively improve the added value of the product on the basis of energy saving and consumption reduction.

[0007] The present invention adopts the following technical scheme: a blast furnace slag hollow glass microsphere preparation system, comprising a mixed cooling medium integrated plate, a rotating cup, a granulation chamber, a gas coolant nozzle, and an atomized liquid coolant nozzle; characterized in that the mixed cooling medium integrated plate is located directly above the rotating cup and is connected to the granulation chamber and fixed to the ground; the rotating cup is driven by a variable frequency drive motor 1, and the gas coolant nozzle and the atomized liquid coolant nozzle are evenly distributed on the mixed cooling medium integrated plate along the circumferential direction; the gas coolant nozzle is driven by a variable frequency drive motor 2, and the atomized liquid coolant nozzle is driven by a variable frequency drive motor 3, and they are respectively moved horizontally along the nozzle moving slide rails parallel to the radial direction of the rotating cup; the gas coolant nozzle is supplied with gas coolant by an air compressor 1 through a conveying pipe 1, and the atomized liquid coolant nozzle is supplied with atomized liquid coolant by an air compressor 2 through a conveying pipe 2, and the blowing directions of the gas coolant nozzle and the atomized liquid coolant nozzle are perpendicular to the horizontal plane of the rotating cup.

[0008] A method for preparing blast furnace slag hollow glass microspheres, characterized in that it comprises the following steps:

[0009] Step 1: Heat the slag to above 1500℃ and then pour it into the heat preservation slag pot, keep the temperature at 1480℃ and wait for slag discharge;

[0010] Step 2: Adjust the rotating cup speed, the speed range is 2000~3000r / min;

[0011] Step 3: Adjust the injection pressure of the gas coolant nozzle and the atomized liquid coolant nozzle respectively, the pressure range is 0.1~0.5MPa;

[0012] Step 4: Use the slide rail to adjust the radial positions of the gas coolant nozzle and the atomized liquid coolant nozzle respectively, with the range of 0~10cm being parallel to the radial direction with the rotation cup projection as the base point;

[0013] Step 5: Tilt the insulation slag pot to discharge the slag, and control the slag dripping temperature at 1450℃±5℃. By adjusting the tilt angle of the insulation slag pot, the dripping mass flow rate is controlled to be 0.3kg / s±0.05kg / s.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] The present invention makes full use of the sensible heat of molten blast furnace slag, and applies a mixed cooling medium during the centrifugal granulation process to cause the slag to undergo granulation and bubble behavior: on the one hand, the gas coolant can promote the secondary breakage of the melt film, enhance the granulation effect, and obtain slag beads with smaller particle sizes; on the other hand, the atomized liquid coolant contacts the melt, and under the combined action of surface tension, can promote film shrinkage, and instantly vaporize the droplets so as to be coated in each slag bead, forming a certain hollowness, and ultimately achieving the purpose of preparing hollow glass microspheres. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the device according to an embodiment of the present invention;

[0017] Figure 2 It is a top view of the mixed cooling medium integrated plate - the radial position of the gas coolant nozzle and the atomized liquid coolant nozzle is the same;

[0018] Figure 3 Top view of the mixed cooling medium integrated plate - the radial positions of the gas coolant nozzle and the atomized liquid coolant nozzle are different.

[0019] In the figure: mixed cooling medium integrated plate 1, rotating cup 2, rotating cup supporting device 3, granulating chamber 4, variable frequency drive motor 1 5-1, variable frequency drive motor 2 5-2, variable frequency drive motor 3 5-3, variable frequency drive motor 5-4, gas coolant nozzle 6-1, atomized liquid coolant nozzle 6-2, air compressor 1 7-1, air compressor 2 7-2, conveying pipeline 1 8-1, conveying pipeline 2 8-2, insulation slag pot 9, slag pot tilting device 10, slag pot supporting device 11, nozzle moving slide rail 12. DETAILED DESCRIPTION

[0020] The present invention is described in further detail below. Example 1

[0021] A system for preparing hollow glass microspheres from blast furnace slag, including a slag pot tilting device 10, the slag pot tilting device 10 is connected to the slag pot supporting device 11 and fixed to the ground, and drives the heat-insulating slag pot 9 to perform a flipping motion to dump the molten slag through a variable frequency drive motor 5-4. It also includes a mixed cooling medium integrated plate 1, which is located directly above the rotating cup 2 and is connected to the granulation chamber 4 and fixed to the ground; the vertical distance between the lower horizontal plane of the mixed cooling medium integrated plate 1 and the upper horizontal plane of the rotating cup 2 is 10 cm, and the mixed cooling medium integrated plate 1 is annular, and its inner diameter is consistent with the outer diameter of the rotating cup, both of which are 20 cm; the rotating cup 2 is driven by a variable frequency drive motor 5-1, and the gas coolant nozzle 6-1 and the atomized liquid coolant nozzle 6-2 are evenly distributed on the mixed cooling medium integrated plate 1 along the circumferential direction; the gas coolant nozzle 6-1 is connected to the granulation chamber 4 through the granulation chamber 4. The variable frequency drive motor 2 5-2 drives, and the atomized liquid coolant nozzle 6-2 is driven by the variable frequency drive motor 3 5-3, and moves horizontally along the nozzle moving slide rail 12 parallel to the radial direction of the rotating cup 2; the gas coolant nozzle 6-1 is supplied with gas coolant by the air compressor 1 7-1 through the conveying pipe 1 8-1, and the atomized liquid coolant nozzle 6-2 is supplied with atomized liquid coolant by the air compressor 2 7-2 through the conveying pipe 2 8-2, and the spraying directions of the gas coolant nozzle 6-1 and the atomized liquid coolant nozzle 6-2 are perpendicular to the horizontal plane of the rotating cup.

[0022] The mixed cooling medium is composed of a gas coolant and an atomized liquid coolant, the gas coolant is single air or single nitrogen, or a mixed gas of air and nitrogen, wherein when the gas coolant is a mixed gas, the volume percentage of air and nitrogen is 1:1; the atomized liquid coolant is high-pressure spray atomized water.

[0023] The number of the gas coolant nozzles 6-1 and the atomized liquid coolant nozzles 6-2 are 6 respectively, and the moving range is 0~10cm outward translation based on the projection of the rotating cup 2; in the circumferential direction, the angle between each gas coolant nozzle 6-1 is 60°, the angle between each atomized liquid coolant nozzle 6-2 is 60°, and the angle between adjacent gas coolant nozzles 6-1 and atomized liquid coolant nozzles 6-2 is 30°. Example 2

[0024] The method for preparing hollow glass microspheres from blast furnace slag is characterized by comprising the following steps:

[0025] Step 1: Heat the molten slag to above 1500°C and inject it into the heat-insulating slag tank 9, keep the temperature constant at 1480°C and wait for slag discharge;

[0026] Step 2: Adjust the speed of rotating cup 2 to a range of 2000~3000r / min;

[0027] Step 3: respectively adjust the spray pressure of the gas coolant nozzle 6-1 and the atomized liquid coolant nozzle 6-2, the pressure range is 0.1~0.5MPa;

[0028] Step 4: Use the slide rails to adjust the radial positions of the gas coolant nozzle 6-1 and the atomized liquid coolant nozzle 6-2 respectively, with the range of 0-10 cm being parallel to the radial direction with the projection of the rotating cup 2 as the base point;

[0029] Step 5: Tilt the thermal insulation slag pot 9 to discharge the slag, and control the slag dripping temperature at 1450°C ± 5°C. By adjusting the tilt angle of the thermal insulation slag pot 9, the dripping mass flow rate is controlled to be 0.3kg / s ± 0.05kg / s.

[0030] The typical composition of blast furnace slag is shown in Table 1.

[0031] Table 1 Typical composition of blast furnace slag

[0032]

[0033] The gas coolant is air. The hollow ratio and particle size distribution of the hollow glass microspheres prepared under different rotating cup 2 speed conditions are shown in Table 2.

[0034] Table 2 Preparation of hollow glass microspheres when the gas coolant is air

[0035]

[0036] The gas coolant is nitrogen. The hollow ratio and particle size distribution of the hollow glass microspheres prepared under different rotating cup 2 speed conditions are shown in Table 3.

[0037] Table 3 Preparation of hollow glass microspheres when the gas coolant is nitrogen

[0038]

[0039] The gas coolant is 50% air and 50% nitrogen. The hollow ratio and particle size distribution of the hollow glass microspheres prepared under different rotating cup 2 speed conditions are shown in Table 4.

[0040] Table 4 Preparation of hollow glass microspheres when the gas coolant is 50% air and 50% nitrogen

[0041]

[0042] To prepare hollow glass microspheres with high hollow ratio and small particle size, nitrogen should be used as the gas coolant and the rotating cup speed should be increased.

[0043] While the slag drips from the insulated slag pot 9 onto the rotating cup 2 for centrifugal granulation, the nozzles uniformly distributed along the circumferential direction in the mixed cooling medium integrated plate 1 above the rotating cup 2 spray out the mixed cooling medium. By matching the rotating speed of the rotating cup 2, the injection pressure of the gas coolant and the atomized liquid coolant, and the radial position of the gas coolant nozzle 6-1 and the atomized liquid coolant nozzle 6-2, the purpose of regulating the hollowness and glass phase of the centrifugally granulated blast furnace slag is achieved. The use of mixed cooling medium to assist the centrifugal granulation of blast furnace slag can not only reduce the energy consumption of the continuous operation of the rotating cup and save water, but also promote the secondary crushing and granulation of the slag film, improve the hollowness and glass phase of the granulated slag, and prepare hollow glass microspheres, which greatly improves the added value of the granulated slag, reduces the floor space of the centrifugal granulation device, and facilitates the recovery of slag beads and waste heat resources in the later stage.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, it is obvious to those skilled in the art that various modifications and changes may be made to the present invention without departing from the purpose and scope of the technical solution of the present invention, and all of them should be included in the protection scope of the present invention.

Claims

1. A blast furnace slag hollow glass microsphere preparation system, comprising a mixed cooling medium integrated plate (1), a rotating cup (2), a granulation chamber (4), a gas coolant nozzle (6-1), and an atomized liquid coolant nozzle (6-2); characterized in that: The mixed cooling medium integrated plate (1) is located directly above the rotating cup (2) and is connected to the granulating chamber (4) and fixed to the ground; the rotating cup (2) is driven by a variable frequency drive motor 1 (5-1); the gas coolant nozzle (6-1) and the atomized liquid coolant nozzle (6-2) are evenly distributed on the mixed cooling medium integrated plate (1) along the circumferential direction; the gas coolant nozzle (6-1) is driven by a variable frequency drive motor 2 (5-2); the atomized liquid coolant nozzle (6-2) is driven by a variable frequency drive motor 3 (5-3 ) are driven to move horizontally along the nozzle moving slide rails (12) parallel to the radial direction of the rotating cup (2); the gas coolant nozzle (6-1) is supplied with gas coolant by air compressor 1 (7-1) through delivery pipe 1 (8-1), and the atomized liquid coolant nozzle (6-2) is supplied with atomized liquid coolant by air compressor 2 (7-2) through delivery pipe 2 (8-2); the spraying directions of the gas coolant nozzle (6-1) and the atomized liquid coolant nozzle (6-2) are perpendicular to the horizontal plane of the rotating cup.

2. The blast furnace slag hollow glass microsphere preparation system according to claim 1, characterized in that: It also comprises a slag pot tilting device (10), wherein the slag pot tilting device (10) is connected to the slag pot supporting device (11) and fixed to the ground, and drives the heat-insulating slag pot (9) to perform a turning movement to dump the molten slag through a variable frequency drive motor (5-4).

3. The blast furnace slag hollow glass microsphere preparation system according to claim 1, characterized in that: The mixed cooling medium is composed of a gas coolant and an atomized liquid coolant, the gas coolant is single air or single nitrogen, or a mixed gas of air and nitrogen, wherein when the gas coolant is a mixed gas, the volume percentage of air and nitrogen is 1:1; the atomized liquid coolant is high-pressure spray atomized water.

4. The blast furnace slag hollow glass microsphere preparation system according to claim 1, characterized in that: The vertical distance between the lower horizontal plane of the mixed cooling medium integrated plate (1) and the upper horizontal plane of the rotating cup (2) is 10 cm.

5. The blast furnace slag hollow glass microsphere preparation system according to claim 1, characterized in that: The mixed cooling medium integrated plate (1) is in the shape of a ring, and its inner diameter is consistent with the outer diameter of the rotating cup, both of which are 20 cm.

6. The blast furnace slag hollow glass microsphere preparation system according to claim 1, characterized in that: The number of the gas coolant nozzles (6-1) and the number of the atomized liquid coolant nozzles (6-2) are respectively 6, and the moving range is 0 to 10 cm outward translation with the projection of the rotating cup (2) as the base point; in the circumferential direction, the angle between each gas coolant nozzle (6-1) is 60°, the angle between each atomized liquid coolant nozzle (6-2) is 60°, and the angle between adjacent gas coolant nozzles (6-1) and atomized liquid coolant nozzles (6-2) is 30°.

7. A method for preparing hollow glass microspheres from blast furnace slag, characterized in that: The blast furnace slag hollow glass microsphere preparation system as claimed in claim 2 comprises the following steps: Step 1: Heat the molten slag to above 1500°C and inject it into the heat-insulating slag pot (9), keep the temperature constant at 1480°C and wait for slag discharge; Step 2: Adjust the speed of the rotating cup (2) to a range of 2000-3000 r / min; Step 3: respectively adjusting the spray pressure of the gas coolant nozzle (6-1) and the atomized liquid coolant nozzle (6-2), the pressure range being 0.1-0.5 MPa; Step 4: Using the slide rails, the radial positions of the gas coolant nozzle (6-1) and the atomized liquid coolant nozzle (6-2) are adjusted respectively, within a range of 0 to 10 cm in parallel to the radial direction with the projection of the rotating cup (2) as the base point; Step 5: The heat-insulating slag pot (9) is tilted to discharge the slag, and the slag dripping temperature is controlled at 1450°C ± 5°C. The dripping mass flow rate is controlled to be 0.3kg / s ± 0.05kg / s by adjusting the tilting angle of the heat-insulating slag pot (9).

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