Steel slag crushing, granulating, quenching, boiling and stabilizing treatment system and treatment method

Abstract

The invention discloses a steel slag crushing, granulating, quenching, boiling and stabilizing treatment system and method, and the treatment system comprises a spraying and crushing mechanism for solidifying and crushing high-temperature steel slag into steel slag blocks, and a waste heat boiling pool for boiling and granulating the crushed steel slag blocks, waste heat of the steel slag blocks is used for providing heat for the boiling pool, and the steel slag blocks are subjected to quenching and boiling granulation; a conveying mechanism for transferring steel slag blocks is arranged between the spraying and crushing mechanism and the waste heat boiling pool; the steel slag is self-pulverized and crushed under the dual effects of quenching and boiling water boiling, efficient cooling and crushing of the steel slag are achieved, meanwhile, CaO and MgO in the steel slag are subjected to a digestion reaction when encountering boiling water, impurities can be removed, and good physical conditions are provided for subsequent crushing, magnetic separation and iron extraction; the problems of low production efficiency, high system investment, large occupied area, direct emission of flue gas without treatment and the like in traditional steel slag hot disintegration treatment are solved, and the method has remarkable economic and social benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature steel slag crushing treatment, and particularly relates to a steel slag crushing, granulating, rapid cooling, boiling and stabilizing treatment system and a treatment method thereof. Background Art

[0002] In recent years, China's annual steel production has exceeded 1 billion tons. For every ton of steel produced, about 120 - 140 kg of steel slag is generated, and the annual output of steel slag exceeds 120 million tons. Steel slag contains two types of resources, namely ferrous metal resources and inorganic materials such as calcium silicate, and has the material properties for resource utilization.

[0003] For the efficient recovery of metallic iron and inorganic material resources in steel slag, it is necessary to first carry out crushing and separation, and then use magnetic separation and other methods to separate the two types of materials, so as to achieve targeted resource utilization. The pretreatment process of steel slag is a prerequisite for the crushing and magnetic separation treatment of steel slag, and more efficient crushing, screening and magnetic separation of steel slag are realized through pretreatment under high-temperature conditions.

[0004] At present, the pretreatment processes of steel slag include hot smothering method, hot splashing method, drum method, air quenching method and other production processes. The hot splashing method has backward production methods, simple and extensive treatment processes, serious environmental pollution, low metal resource recovery rate and other problems, and should be phased out as soon as possible; the drum method is only applicable to liquid steel slag with good fluidity, the steel slag treatment rate is less than 50%, and the equipment operation cost is high and the failure rate is high. At present, it is only used in a few iron and steel enterprises within the Baosteel system; the air quenching method uses a large amount of air volume to blow and cool the liquid steel slag into fine particles, which is only applicable to the treatment of liquid steel slag, and the recovery rate of steel metallic iron resources is low. There is only one set of air quenching equipment in MaSteel in China.

[0005] The hot smothering method process is the most commonly used process in current steel slag treatment, with a series of advantages such as wide adaptability, good pulverization effect of steel slag after hot smothering, beneficial to slag-iron separation, high recovery rate of metallic iron, and qualified stability of tail slag. The hot smothering method is divided into two processes: pool hot smothering and pressure hot smothering. The pool hot smothering method adopts an engineering mechanized operation process method, that is, an excavator is used to scrape and crush the high-temperature steel slag poured into the hot smothering pool. There is no dust removal device in the operation process of pouring slag, scraping slag and discharging slag in the pool hot smothering method, and it is necessary to further improve the equipment level and environmental emissions. The pressure hot smothering method uses a mechanized roller press crusher to crush the high-temperature steel slag, realizing the equipment automation of the crushing process. However, the hot smothering system uses a large number of pressure vessels, the system equipment occupies a large space, the investment is high, and the hot smothering flue gas is discharged without organization, having certain environmental hazards. At present, new domestic steel slag treatment projects are basically based on the pressure hot smothering process, but this process still has many problems such as large space occupation and high investment of steel slag treatment equipment, which urgently need to be solved. Summary of the Invention

[0006] Technical objective: Aiming at the deficiencies of the existing high-temperature steel slag treatment methods, the present invention discloses a steel slag crushing, granulating, quenching, boiling and stabilizing treatment system and a treatment method.

[0007] Technical solution: To achieve the above technical objective, the present invention adopts the following technical solutions: A steel slag crushing, granulating, quenching, boiling and stabilizing treatment system includes a spray crushing mechanism for solidifying and crushing high-temperature steel slag into steel slag blocks and a waste heat boiling tank for boiling and granulating the crushed steel slag blocks. The waste heat of the steel slag blocks is used to provide heat for the boiling tank to quench and boil and granulate the steel slag blocks; a conveying mechanism for transferring the steel slag blocks is arranged between the spray crushing mechanism and the waste heat boiling tank.

[0008] Preferably, the spray crushing mechanism of the present invention includes a slag tank, a spray head arranged along the length direction of the slag tank, and a slag raking machine slidably arranged above the slag tank. The slag raking machine is provided with a rotary crushing tooth roller for crushing and pushing the solidified steel slag. The rotary crushing tooth roller rotates to crush the solidified steel slag and push the crushed steel slag.

[0009] Preferably, the conveying mechanism of the present invention includes a discharge chute obliquely arranged at the end of the slag tank. The crushed steel slag blocks in the slag tank are conveyed into the waste heat boiling tank located at the end of the discharge chute through the discharge chute. Along the inclined direction of the discharge chute, a spray gun is arranged at the upper end of the discharge chute for assisting the movement of the steel slag blocks and further cooling the steel slag blocks.

[0010] Preferably, a slag grabbing machine for taking out the granulated steel slag is arranged above the waste heat boiling tank of the present invention, and a water draining tank is arranged on one side of the waste heat boiling tank. The granulated steel slag grabbed by the slag grabbing machine is drained in the water draining tank and then loaded and transported out.

[0011] Preferably, both the spray crushing mechanism and the waste heat boiling tank of the present invention are arranged in a closed enclosure. An inlet slag door and an outlet slag door are opened on the enclosure. The high-temperature steel slag is transported into the enclosure through a slag tank and a slag tipping machine from the inlet slag door, and the granulated and crushed granulated steel slag is removed from the outlet slag door.

[0012] Preferably, the enclosure of the present invention is connected with a dust removal mechanism for purifying the flue gas generated during the steel slag crushing process through a flue. The dust removal mechanism includes a primary dust collector, an ultra-clean dust collector, a fan and a chimney arranged in sequence.

[0013] The present invention discloses a steel slag crushing, granulating, quenching, boiling and stabilizing treatment method, which uses the above treatment system and includes the steps: S01. Pour high-temperature steel slag into the slag tank, spray water with the spray head to cool and fix the high-temperature steel slag, and at the same time, the slag raking machine stirs and crushes the solidified high-temperature steel slag to form steel slag blocks; S02. The steel slag blocks are sent into the waste heat boiling pool by the conveying mechanism. The waste heat boiling pool rapidly cools the steel slag blocks and uses the steel slag blocks to provide heat for the waste heat boiling pool to keep the water temperature in the waste heat boiling pool in a boiling state. Moreover, the components of the steel slag blocks react with water to expand and pulverize, granulating and crushing the steel slag blocks. Finally, the granulated steel slag after crushing is taken out from the waste heat boiling pool.

[0014] Preferably, the water spraying amount for cooling and solidifying the high-temperature steel slag by the spray head of the present invention is 0 - 0.4t, the stirring, crushing and water spraying cooling time of the slag raking machine is 2 - 20 minutes, and the temperature range of the obtained steel slag blocks is 400 - 1200°C.

[0015] Preferably, after crushing in the present invention, 80% by mass of the steel slag blocks have a particle size within 50mm.

[0016] Preferably, the boiling treatment time of the steel slag blocks in the waste heat boiling pool of the present invention is 0.5 - 3h, and 80% by mass of the granulated steel slag after boiling has a particle size within 10mm.

[0017] Beneficial effects: A steel slag crushing, granulating, rapid cooling and boiling stabilization treatment system and treatment method disclosed by the present invention have the following beneficial effects: The present invention first preliminarily cools, solidifies and granulates the incoming high-temperature steel slag to ensure that no liquid steel slag flows into the waste heat boiling pool, effectively avoiding the danger of explosion caused by slag containing water. It makes full use of the waste heat of the steel slag. Under the dual action of rapid cooling and boiling water boiling, the steel slag self-pulverizes and breaks, realizing the efficient cooling and crushing of the steel slag. At the same time, CaO and MgO in the steel slag react with boiling water to remove impurities, providing good physical conditions for subsequent crushing and magnetic separation for iron extraction; it solves the problems of low production efficiency, high system investment, large floor area, and direct emission of flue gas without treatment in the traditional steel slag heat soaking treatment, and has remarkable economic and social benefits. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0019] Figure 1 It is the overall structure diagram of the treatment system of the present invention; Figure 2 It is the cross-sectional view of the treatment system of the present invention along the position of the discharge chute; Among them, 1 - waste heat boiling tank, 2 - slag tank, 3 - spray head, 4 - slag skimmer, 5 - rotating crushing tooth roller, 6 - discharge chute, 7 - high-temperature steel slag, 8 - steel slag block, 9 - spray gun, 10 - slag grabber, 11 - water drainage tank, 12 - granulated steel slag, 13 - enclosure, 14 - slag inlet door, 15 - slag outlet door, 16 - slag pot, 17 - slag tipping machine, 18 - flue, 19 - primary dust collector, 20 - ultra-clean dust collector, 21 - fan, 22 - chimney. Detailed implementation manners

[0020] Now, reference will be made in detail to the embodiments of the present disclosure, one or more examples of which are set forth below in this text. Each embodiment and example is provided by way of explanation of the devices, components, and materials of the present disclosure, and not by way of limitation. On the contrary, the following description provides a convenient illustration for implementing the exemplary embodiments of the present disclosure. In fact, it will be clear to those skilled in the art that various modifications and variations can be made within the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0021] As Figure 1 - Figure 2 shown, a steel slag crushing, granulating, rapid cooling, boiling, and stabilizing treatment system disclosed by the present invention includes a spray crushing mechanism for solidifying and crushing high-temperature steel slag 7 into steel slag blocks 8 and a waste heat boiling tank 1 for boiling and granulating the crushed steel slag blocks. The waste heat of the steel slag blocks is used to provide heat for the boiling tank 1 to rapidly cool and boil and granulate the steel slag blocks; a conveying mechanism for transferring the steel slag blocks is arranged between the spray crushing mechanism and the waste heat boiling tank 1.

[0022] Specifically, as Figure 2 shown, the spray crushing mechanism of the present invention includes a slag tank 2, a spray head 3 arranged along the length direction of the slag tank 2, and a slag skimmer 4 slidably arranged above the slag tank 2. The main body of the slag tank is a U-shaped groove made of reinforced concrete, the thickness of the two side concrete tank plates is not less than 20 cm, a steel structure lining plate is installed on the inner side of the concrete tank plate, the thickness of the steel structure lining plate is not less than 20 mm, the bottom plate of the slag tank 2 is a steel plate, the thickness of the steel plate is not less than 30 mm, and the cushion layer on the bottom plate is coarse-grained steel slag, slag, etc., and the particle size is 10 - 60 mm.

[0023] The slag skimmer 4 is provided with a rotating crushing tooth roller 5 for crushing and pushing the solidified steel slag, and the rotating crushing tooth roller 5 rotates to crush the solidified steel slag and push the crushed steel slag.

[0024] The conveying mechanism includes a discharge chute 6 inclined at the end of the slag tank 2. The broken steel slag blocks 8 in the slag tank 2 are conveyed to the waste heat boiling pool 1 located at the end of the discharge chute through the discharge chute 6. Along the inclined direction of the discharge chute 6, a spray gun 9 is provided at the upper end of the discharge chute 6 to assist in the movement of the steel slag blocks 8 and further cool the steel slag blocks. The downward inclination angle of the discharge chute should not be less than 30°, and a steel structure lining plate is installed on the upper part, with the thickness of the steel structure lining plate not less than 20 mm. The spray gun is a stainless steel pressure water gun, and the water pressure used is not less than 0.3 MPa. The spray gun 9 cooperating with the inclined discharge chute 6 can quickly convey the steel slag blocks, avoid blockage, and at the same time, the water flow sprayed by the spray gun can continue to cool the steel slag blocks and replenish water for the waste heat boiling pool 1, enabling continuous granulation and crushing of the steel slag.

[0025] In the embodiment of the present invention, the main structure of the waste heat boiling pool is a reinforced concrete structure pool with a volume not less than 20 m 3 . The thickness of the concrete used at the bottom and around the inner wall of the waste heat boiling pool is not less than 20 cm. Steel structure lining plates are preferably installed on the bottom and the inner sides around the waste heat boiling pool, with the thickness of the steel structure lining plates not less than 20 mm.

[0026] A slag grabber 10 for taking out the granulated steel slag 12 is arranged above the waste heat boiling pool 1 of the present invention. A water drainage trough 11 is arranged on one side of the waste heat boiling pool 1. After the granulated steel slag 12 grabbed by the slag grabber 10 is drained in the water drainage trough 11, it is loaded and transported out. The slag grabber is an electric hydraulic grab bucket, and the volume of the grab bucket is not less than 3 m 3 . The water drainage trough is of reinforced concrete structure, with a steel structure lining plate laid on it. The thickness of the steel structure lining plate is not less than 20 cm, and a steel slag cushion layer is laid on the steel structure lining plate to protect the lining plate. The water drainage trough slopes downward by 3 - 8° towards the waste heat boiling pool to facilitate the water carried by the granulated steel slag during the slag discharging process to flow back into the waste heat boiling pool.

[0027] To facilitate the treatment of the flue gas during the crushing process and ensure the air cleanliness of the external working space, the spray crushing mechanism and the waste heat boiling pool 1 of the present invention are both arranged in a closed enclosure 13. An inlet slag door 14 and an outlet slag door 15 are opened on the enclosure 13, and both are steel structure frame high-temperature resistant doors that open and close by lifting up and down. The high-temperature steel slag 7 is transported into the enclosure through the slag tank 16 and the slag tipping machine 17 from the inlet slag door 14, and the granulated steel slag 12 after granulation and crushing is removed from the outlet slag door 15, enabling the crushing process to be carried out in a closed environment. The enclosure 13 is connected to a dust removal mechanism for purifying the flue gas generated during the steel slag crushing process through a flue 18. The dust removal mechanism includes a primary dust collector 19, an ultra-clean dust collector 20, a fan 21, and a chimney 22 arranged in sequence. The flue is a steel structure flue gas pipeline. The primary dust collector and the ultra-clean dust collector are both wet dust collectors, the fan is a variable frequency fan with a wind pressure not less than 3000 Pa, and the chimney is a steel structure chimney, enabling the flue gas to be discharged after purification treatment and effectively protecting the external environment.

[0028] The present invention also discloses a method for stabilizing steel slag by crushing, granulating, quenching and boiling, which uses the above-mentioned treatment system and includes the following steps: S01. Pour high-temperature steel slag into the slag tank, and spray water with a nozzle to cool and solidify the high-temperature steel slag. At the same time, a slag raking machine stirs and crushes the solidified high-temperature steel slag to form steel slag blocks; When pouring the slag, by opening the closing door, the slag pot filled with high-temperature steel slag travels through the slag pouring machine to the lower part of the closed cover and above the slag tank, and the high-temperature steel slag is poured on the cushion layer on one side of the slag tank close to the slag inlet door. The slag pouring machine retreats the slag pot after pouring the slag outside the closed cover and closes the slag pouring door.

[0029] The water pressure of the nozzle is not less than 0.2 MPa, and the water spraying amount is set based on the amount of high-temperature steel slag that needs to be cooled and solidified to ensure sufficient cooling and solidification effect, ensure that no liquid steel slag flows into the waste heat boiling pool, and improve safety. In the embodiment of the present invention, the water spraying amount of the nozzle 3 for cooling the high-temperature steel slag 7 in the cooling and solidification stage is 0 - 0.4 t.

[0030] The initial temperature of the high-temperature steel slag 1 is 1200 - 1650 °C. After cooling and solidifying, it is crushed by a slag raking machine. The slag raking machine 4 stirs and crushes the high-temperature steel slag 7 in the slag tank 2. During this process, the nozzle 3 continues to spray water for cooling. The stirring, crushing and water spraying cooling time is 2 - 20 minutes. The temperature range of the obtained steel slag blocks 8 is 400 - 1200 °C, and 80% of the steel slag blocks 12 by mass have a particle size within 50 mm. Then, the steel slag blocks 8 are pushed from above the slag tank 2 to the discharge chute 6 at a certain rate by the rotating crushing tooth roller 5 of the slag raking machine 4. At the same time, the spray gun 9 is opened to promote the further cooling of the steel slag blocks 8 and supplement water into the waste heat boiling pool 1. Under the dual action of the gravity of the downward inclination of the discharge chute 6 and the spray pressure water of the spray gun 9, the steel slag blocks 8 gradually descend into the waste heat boiling pool 1.

[0031] S02. The steel slag blocks are sent into the waste heat boiling pool by a conveying mechanism. The waste heat boiling pool quenches the steel slag blocks and uses the steel slag blocks to provide heat for the waste heat boiling pool to keep the water temperature in the waste heat boiling pool in a boiling state. Moreover, the components of the steel slag blocks react with water to expand and pulverize, granulating and crushing the steel slag blocks. Finally, the crushed granulated steel slag is taken out from the waste heat boiling pool. The grab crane 10 is used to take out the granulated steel slag 12 and place it on the water drainage trough 11. After placing for a certain time, the water drainage is completed so that the water content of the granulated steel slag 12 is reduced to a certain extent. The slag discharge door 15 is opened, and a forklift is used to load and transport the granulated steel slag 12.

[0032] The steel slag blocks 8 that fall into the waste heat boiling pool 1 still have a certain temperature condition. When soaked in boiling water, the temperature rapidly drops from a high temperature of 400 - 1200 °C to within 100 °C, providing heat for the water temperature in the waste heat boiling pool 1 and maintaining the water temperature condition in the waste heat boiling pool 1. The steel slag blocks 8 are rapidly cooled in the waste heat boiling pool 1. The high-temperature steel slag blocks 12 undergo physical shrinkage and are sharply broken under this cooling effect, and react with water to produce expansion and pulverization. CaO and MgO in the broken steel slag particles react with boiling water to form Ca(OH)2 and Mg(OH)2. This process produces a volume expansion of approximately 100%. The Ca(OH)2 and Mg(OH)2 produced by the reaction dissolve and detach from the steel slag blocks 12 under the boiling action of the boiling water, which all promotes the pulverization and breaking of the steel slag blocks 8. Under the dual actions of rapid cooling and expansion and pulverization due to the digestion reaction, the steel slag blocks 12 are transformed into granulated steel slag 12 after a certain period of treatment. The boiling treatment time of the steel slag blocks 8 in the waste heat boiling pool 1 is 0.5 - 3 h. After boiling, the steel slag blocks 8 are transformed into granulated steel slag 12. 80% of the mass ratio of the granulated steel slag 12 has a particle size within 10 mm, and after treatment, it has good stability and a water immersion expansion rate of less than 1%.

[0033] During the entire treatment process of the high-temperature steel slag 7 from slag pouring, cooling and solidification, slag skimming and discharging, waste heat boiling, to slag discharging and transporting out, the fan is turned on for 24 h for dust removal operation. The dust-containing wet flue gas in the closed hood 13 is discharged to the outside through the flue 18, the primary dust collector 19, the ultra-clean dust collector 20, the fan 21, and the chimney 22 in sequence. After being treated by the primary dust collector 22, the concentration of the flue gas is 50 - 200 mg / Nm 3 , and after being treated by the ultra-clean dust collector 23, the concentration of the flue gas does not exceed 10 mg / Nm 3 .

[0034] The above are only the preferred embodiments of the present invention. It should be noted that: for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A steel slag crushing, granulating, quenching and boiling stabilization treatment system, characterized in that It includes a spraying and crushing mechanism for solidifying and crushing high-temperature steel slag (7) into steel slag blocks (8), and a waste heat boiling tank (1) for boiling and granulating the crushed steel slag blocks. The waste heat of the steel slag blocks is used to provide heat for the boiling tank (1) to rapidly cool and boil-granulate the steel slag blocks. A conveying mechanism for transferring the steel slag blocks is arranged between the spraying and crushing mechanism and the waste heat boiling tank (1).

2. The stabilized treatment system for steel slag crushing, granulating, quenching and boiling according to claim 1, characterized in that The spraying and crushing mechanism includes a slag tank (2), a spray head (3) arranged along the length direction of the slag tank (2), and a slag rake (4) slidably arranged above the slag tank (2). The slag rake (4) is provided with a rotary crushing tooth roller (5) for crushing and pushing the solidified steel slag. The rotary crushing tooth roller (5) rotates to crush the solidified steel slag and push the crushed steel slag.

3. A steel slag crushing, granulating, quenching and boiling stabilization treatment system according to claim 2, characterized in that, The conveying mechanism includes a discharge chute (6) inclined at the end of the slag tank (2). The crushed steel slag blocks (8) in the slag tank (2) are conveyed into the waste heat boiling tank (1) located at the end of the discharge chute through the discharge chute (6). Along the inclined direction of the discharge chute (6), a spray gun (9) is arranged at the upper end of the discharge chute (6) to assist in moving the steel slag blocks (8) and further cool the steel slag blocks.

4. A steel slag crushing, granulating, quenching and boiling stabilization treatment system according to claim 1, characterized in that, A slag grabber (10) for taking out the granulated steel slag (12) is arranged above the waste heat boiling tank (1). A water drainage trough (11) is arranged on one side of the waste heat boiling tank (1). The granulated steel slag (12) grabbed by the slag grabber (10) is drained in the water drainage trough (11) and then loaded and transported out.

5. A steel slag crushing, granulating, quenching and boiling stabilization treatment system according to claim 1, characterized in that, Both the spraying and crushing mechanism and the waste heat boiling tank (1) are arranged in a closed enclosure (13). An inlet slag door (14) and an outlet slag door (15) are opened on the enclosure (13). The high-temperature steel slag (7) is transported into the enclosure through a slag pot (16) and a slag tipping machine (17) from the inlet slag door (14), and the granulated and crushed granulated steel slag (12) is removed from the outlet slag door (15).

6. A steel slag crushing, granulating, quenching and boiling stabilization treatment system according to claim 5, characterized in that, The enclosure (13) is connected through a flue (18) to a dust removal mechanism for purifying the flue gas generated during the steel slag crushing process. The dust removal mechanism includes a primary dust collector (19), an ultra-clean dust collector (20), a fan (21), and a chimney (22) arranged in sequence.

7. A method for stabilizing steel slag by crushing, granulating, quenching and boiling, using the treatment system described in any one of claims 1-6, characterized in that, It includes the steps of: S01. Pour high-temperature steel slag into the slag tank, the spray head sprays water to cool and solidify the high-temperature steel slag, and at the same time, the slag rake stirs and crushes the solidified high-temperature steel slag to form steel slag blocks; S02. The steel slag blocks are sent into the waste heat boiling tank by the conveying mechanism. The waste heat boiling tank rapidly cools the steel slag blocks, and the steel slag blocks provide heat for the waste heat boiling tank to keep the water temperature in the waste heat boiling tank at the boiling state. Moreover, the components of the steel slag blocks react with water to expand and pulverize, granulating and crushing the steel slag blocks. Finally, the crushed granulated steel slag is taken out from the waste heat boiling tank.

8. A method for stabilizing steel slag by crushing, granulating, quenching and boiling according to claim 7, characterized in that The water spraying amount of the spray head for cooling and solidifying the high-temperature steel slag is 0 - 0.4t, the stirring, crushing and water spraying cooling time of the slag rake is 2 - 20 minutes, and the temperature range of the obtained steel slag blocks is 400 - 1200°C.

9. A method for stabilizing steel slag by crushing, granulating, quenching and boiling according to claim 8, characterized in that, After crushing, 80% by mass of the steel slag blocks have a particle size within 50mm.

10. A method for stabilizing steel slag by crushing, granulating, quenching and boiling according to claim 7, characterized in that, The boiling treatment time of the steel slag block in the waste heat boiling tank is 0.5 to 3 hours, and after boiling, 80% of the granulated steel slag by mass has a particle size within 10 mm.

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