Melted metallurgical slag granulation and waste heat recovery system

Abstract

The invention provides a molten metallurgical slag granulation and waste heat recovery system. The molten metallurgical slag granulation and waste heat recovery system comprises a molten metallurgical slag granulation device and a waste heat recovery device, the molten metallurgical slag granulating device comprises a granulating machine, a granulating bed and a granulating cover; the granulating machine comprises a granulating roller and a granulating machine driving device, the granulating bed comprises a moving bed and a granulating bed driving device, and the granulating bed driving device drives the moving bed to reciprocate between a slag receiving position and a granulating position; the waste heat recovery device comprises a flue gas jet spray pipe, a waste heat boiler, a dust removal device and a circulating fan; the flue gas jet spray pipe is fixed inside the granulation cover, an air outlet of the granulation cover is connected with the dust removal device, the dust removal device is connected with the waste heat boiler through an air pipe, an inlet of the circulating fan is connected with the waste heat boiler, and an outlet of the circulating fan is connected with the flue gas jet spray pipe. The slag treatment process can be effectively shortened, heat loss of molten slag in the transfer process is reduced, the waste heat recovery efficiency is improved, efficient recycling of heat energy is achieved, and energy waste is reduced.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, and in particular to a system for granulation and waste heat recovery of molten metallurgical slag. Background Technology

[0002] Currently, the main method for treating metallurgical slag in the market is wet treatment, which not only wastes a lot of water resources and poses explosion safety issues, but also brings problems such as waste gas and wastewater treatment. Furthermore, the molten steel slag has a large amount of latent heat and sensible heat that cannot be recovered and utilized.

[0003] Generally, molten metallurgical slag is poured into an intermediate slag pot, transported by a transfer car to a slag yard truck, and then lifted by a crane onto a slag pot tilter. The slag is then tilted and dumped onto a granulation bed for crushing. This process results in a long metallurgical slag transportation process, significant heat loss, and high costs. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a granulation and waste heat recovery system for molten metallurgical slag.

[0005] This invention provides a system for granulation and waste heat recovery of molten metallurgical slag, the system comprising a granulation device for molten metallurgical slag and a waste heat recovery device; wherein, The molten metallurgical slag granulation device includes a granulator, a granulation bed, and a granulation hood; the granulator includes a granulation roller and a granulator drive device, the granulation bed includes a moving bed and a granulation bed drive device that is connected to the moving bed in a transmission manner, the granulation bed drive device being used to drive the moving bed to reciprocate between a slag receiving position located outside the granulation hood and a granulation position located inside the granulation hood; The waste heat recovery device includes a flue gas jet nozzle, a waste heat boiler, a dust removal device, and a circulating fan; the flue gas jet nozzle is fixed inside the granulation hood, the outlet of the granulation hood is connected to the dust removal device, the dust removal device is connected to the waste heat boiler through a duct, the inlet of the circulating fan is connected to the waste heat boiler, and the outlet of the circulating fan is connected to the flue gas jet nozzle.

[0006] Furthermore, the movable bed is provided with low baffles at both ends along its direction of movement, and high baffles at the other two ends; wherein, When the moving bed moves to the point where the granulator contacts the low baffle, both the granulator and the moving bed begin to run in reverse.

[0007] Furthermore, the bottom of the mobile bed is provided with wheels and tracks to support the wheels; The granulation bed drive device includes a drive motor, a transmission gear, and a transmission rack. The transmission gear is connected to the output shaft of the drive motor and meshes with the transmission rack. The transmission rack is fixedly connected to the wheel.

[0008] Furthermore, the first end of the track is located outside the granulation hood and corresponds to the slag receiving position, and the second end of the track extends into the granulation hood and corresponds to the bottom of the slag outlet of the metallurgical furnace.

[0009] Furthermore, the bearing housing of the granulator is equipped with a lifting hydraulic cylinder; The piston rod of the lifting cylinder is fixedly connected to the granulating roller to drive the granulating roller to rise and fall so that the moving bed moves out of the bottom of the granulating roller.

[0010] Furthermore, the granulation hood is equipped with a switchable door above the track; wherein, When the door is opened and closed, the moving bed can move in and out of the granulation hood along the track; when the door is closed, the granulation hood forms a sealed space.

[0011] Furthermore, the door is raised and lowered by a winch or hydraulic cylinder.

[0012] Furthermore, a hopper is provided below the granulator and the moving bed, and a feeder is installed at the bottom of the hopper to uniformly convey the material to the conveyor below.

[0013] Furthermore, the flue gas jet nozzles are arranged in parallel with the granulating rollers, and the flue gas jet nozzles are one or more rows of nozzles. The bottom of the nozzles is higher than the low baffle of the moving bed, and the upper end of the nozzles is connected to the circulating fan through pipes.

[0014] Furthermore, the moving bed is lined with dry solid metallurgical slag.

[0015] The molten metallurgical slag granulation and waste heat recovery system of this invention directly receives molten metallurgical slag via a moving bed, eliminating the intermediate slag pot, transfer vehicle, and crane lifting steps required in traditional processes. This significantly shortens the slag handling process, reduces heat loss during molten slag transfer, and improves waste heat recovery efficiency. A closed-loop circulation system (jet nozzle → granulation hood → dust removal → waste heat boiler → circulating fan → jet nozzle) converts the heat of high-temperature flue gas into steam via the waste heat boiler, achieving efficient heat energy recovery and utilization, and reducing energy waste. The reuse of circulating flue gas avoids the problem of direct heat emission in traditional wet processing, improving system energy efficiency. Furthermore, the dry processing method of this invention replaces traditional wet processes, completely solving the problems of water waste, wastewater, and exhaust gas pollution in wet slag treatment, while eliminating the explosion risk caused by water cooling, aligning with the development trend of green metallurgy. The sealed design of the granulation hood, combined with the dust removal device, effectively suppresses dust escape and reduces environmental pollution. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a molten metallurgical slag granulation and waste heat recovery system according to an embodiment of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Figure 1 This is a schematic diagram of a molten metallurgical slag granulation and waste heat recovery system according to an embodiment of the present invention. The embodiment of the present invention relates to a molten metallurgical slag granulation and waste heat recovery system, the system comprising a molten metallurgical slag granulation device and a waste heat recovery device.

[0019] Specifically, such as Figure 1 As shown, the molten metallurgical slag granulation device includes a granulator 1, a granulation bed, and a granulation hood 2; the granulator 1 includes a granulation roller and a granulator drive device, the granulation bed includes a moving bed 3 and a granulation bed drive device 4 that is connected to the moving bed 3 in a transmission manner, the granulation bed drive device 4 being used to drive the moving bed 3 to reciprocate between a slag receiving position located outside the granulation hood 2 and a granulation position located inside the granulation hood 2.

[0020] Continue to refer to Figure 1The waste heat recovery device includes a flue gas jet nozzle 5, a waste heat boiler 6, a dust removal device, and a circulating fan 7. The flue gas jet nozzle 5 is fixed inside the granulation hood 2. The outlet of the granulation hood 2 is connected to the dust removal device. The dust removal device is connected to the waste heat boiler 6 through a duct. The inlet of the circulating fan 7 is connected to the waste heat boiler 6, and the outlet of the circulating fan 7 is connected to the flue gas jet nozzle 5.

[0021] Specifically, when performing granulation of molten metallurgical slag and waste heat recovery, refer to Figure 1 The moving bed 3 is positioned outside the granulation hood 2 in the slag receiving area, i.e., at the slag receiving location. Dry, solid metallurgical slag can be laid inside the moving bed 3, and the molten metallurgical slag is poured directly onto it. After receiving the slag, the moving bed 3 enters the granulation hood 2, where the granulator contacts the metallurgical slag. Then, the circulating fan 7 is started, and the circulating flue gas is sprayed directly onto the surface of the metallurgical slag through the flue gas jet nozzle 5, raising the temperature of the flue gas. The granulator starts to crush and granulate the metallurgical slag, and the moving bed 3 moves linearly in the direction of the granulator's stirring. When the moving bed 3 reaches its limit position (e.g., when the granulator is about to contact its lower baffle), the granulator begins to reverse, and the moving bed also begins to reverse, continuing the granulation process to form solid granules from the molten metallurgical slag. The high-temperature flue gas is discharged through the outlet of the granulation hood 2 and enters the waste heat boiler 6, where it undergoes heat exchange to generate steam for external use. After heat exchange, the high-temperature flue gas cools down and is then sent to the flue gas jet nozzle 5 via the circulating fan 7, where it is sprayed onto the metallurgical slag for heat exchange. This cycle repeats, achieving slag cooling and granulation, and waste heat recovery from the metallurgical slag. As the metallurgical slag continues to cool, when the high-temperature flue gas can no longer meet the heat exchange conditions of the waste heat boiler, the circulating fan stops, and slag unloading begins. The moving bed 3 moves in the opposite direction to the mixing direction of the granulator, and the interaction between the granulator and the moving bed 3 pushes the material on the moving bed 3 into the lower hopper. The bottom feeder of the hopper is started, outputting solid low-temperature metallurgical slag, which is then transferred by the conveyor.

[0022] The molten metallurgical slag granulation and waste heat recovery system of this invention directly receives molten metallurgical slag via a moving bed, eliminating the intermediate slag pot, transfer vehicle, and crane lifting steps required in traditional processes. This significantly shortens the slag handling process, reduces heat loss during molten slag transfer, and improves waste heat recovery efficiency. A closed-loop circulation system (jet nozzle → granulation hood → dust removal → waste heat boiler → circulating fan → jet nozzle) converts the heat of high-temperature flue gas into steam via the waste heat boiler, achieving efficient heat energy recovery and utilization, and reducing energy waste. The reuse of circulating flue gas avoids the problem of direct heat emission in traditional wet processing, improving system energy efficiency. Furthermore, the dry processing method of this invention replaces traditional wet processes, completely solving the problems of water waste, wastewater, and exhaust gas pollution in wet slag treatment, while eliminating the explosion risk caused by water cooling, aligning with the development trend of green metallurgy. The sealed design of the granulation hood, combined with the dust removal device, effectively suppresses dust escape and reduces environmental pollution.

[0023] Referring to 1, the moving bed 3 is provided with low baffles at both ends along its moving direction and high baffles at the other two ends; wherein, when the moving bed 3 moves to the point where the granulator contacts the low baffles, both the granulator and the moving bed 3 begin to run in reverse.

[0024] The molten metallurgical slag granulation and waste heat recovery system of this invention utilizes a linkage design between the moving bed and the granulator (reversing direction after contact with the low baffle) to repeatedly crush and agitate the metallurgical slag during reciprocating motion. This avoids localized ungranulation or agglomeration, improving granulation uniformity and efficiency. Furthermore, the low baffle acts as a mechanical limit trigger signal, ensuring synchronous reversal between the granulator and the moving bed. This prevents slag accumulation or equipment overload caused by unidirectional operation, reducing the risk of mechanical jamming and extending equipment life. Reversing direction triggered by the low baffle eliminates the need for additional sensors or manual intervention, achieving automated control of the granulation process, reducing human error, and improving system stability. Moreover, the reciprocating motion extends the residence time of the molten slag within the granulation hood, allowing for sufficient heat exchange between the circulating flue gas from the jet nozzle and the slag, maximizing waste heat recovery and increasing the steam output of the waste heat boiler. Finally, during normal granulation and crushing, the high baffle prevents slag from leaking out from both sides. Leaked slag is difficult to clean. Normally, during material pushing, the material will be higher than the low baffle and thus pushed out of the granulation bed. At this time, it is necessary to prevent slag from leaking out from the high baffle to both sides. The low baffle, combined with the reverse operation mechanism, prevents the moving bed from overtraveling and deviating from the track, ensuring operational safety.

[0025] Continue to refer to Figure 1 The bottom of the moving bed 3 is provided with wheels and a track 8 for supporting the wheels; the granulation bed drive device 4 includes a drive motor, a transmission gear and a transmission rack. The transmission gear is connected to the output shaft of the drive motor and meshes with the transmission rack. The transmission rack is fixedly connected to the wheels.

[0026] The molten metallurgical slag granulation and waste heat recovery system of this invention achieves high-precision linear motion of the moving bed along the track through gear and rack meshing transmission (drive motor → transmission gear → transmission rack → wheel), avoiding slippage and offset problems that may occur with traditional chain or belt drives, and ensuring the positioning accuracy of the moving bed during slag receiving, granulation, and unloading processes. The gear and rack transmission mechanism has high torque output characteristics, can withstand the heavy load of molten metallurgical slag and the moving bed, and adapts to the continuous operation requirements under high-temperature conditions, significantly improving system reliability. The design of the transmission rack being fixedly connected to the wheel ensures that the movement speed of the moving bed is strictly synchronized with the speed of the drive motor, facilitating automated collaborative control with the reverse operation of the granulator and reducing manual intervention. The drive motor and transmission gear are arranged outside the granulation hood to avoid damage to the drive device from high temperature and dust; the integrated fixing of the rack and wheel simplifies the transmission structure and reduces maintenance complexity.

[0027] Continue to refer to Figure 1 The first end of the track 8 is located outside the granulation hood 2 and corresponds to the slag receiving position, and the second end of the track 8 extends into the granulation hood 2 and corresponds to the bottom of the slag outlet of the metallurgical furnace.

[0028] The molten metallurgical slag granulation and waste heat recovery system of this invention features a track extending directly below the slag outlet of the metallurgical furnace. This allows the moving bed to directly receive high-temperature molten metallurgical slag, eliminating the need for intermediate ladles, transfer cars, and crane lifting, significantly shortening the process flow and reducing heat loss during molten slag transfer. Furthermore, the track runs through the inside and outside of the granulation hood, forming a continuous "slag receiving-granulation-discharging" operation path. The moving bed can complete the entire process without turning or changing tracks, saving equipment floor space and improving system operating efficiency. The metallurgical furnace slag outlet and the granulation hood are directly connected by the track, avoiding manual intervention in the transfer of high-temperature molten slag and eliminating the safety risks of slag pot tipping (such as slag splashing and explosions) in traditional processes. It also reduces the high-temperature radiation area within the workshop. Finally, the second end of the track extends into the granulation hood, and with the sealing design of the opening and closing doors, ensures that the molten slag remains in a closed environment from receiving to granulation, effectively suppressing the escape of dust and harmful gases and meeting environmental emission standards.

[0029] Continue to refer to Figure 1 The bearing housing of the granulator is equipped with a lifting cylinder; the piston rod of the lifting cylinder is fixedly connected to the granulating roller 3 to drive the granulating roller to rise and fall so that the moving bed moves out of the bottom of the granulating roller.

[0030] The granulation and waste heat recovery system for molten metallurgical slag in this invention utilizes a lifting cylinder to raise the granulation roller (exceeding the low baffle of the moving bed), providing mechanical clearance for the moving bed to move out of the bottom of the granulation roller and ensuring smooth entry and exit of the moving bed along the track within the granulation hood, avoiding equipment interference. When the granulation roller descends, it directly contacts the molten slag inside the moving bed. The cylinder precisely controls the roller pressure, preventing insufficient granulation or equipment overload due to uneven pressure, thus improving the uniformity of slag crushing. When maintenance or cleaning of the granulation roller is required, it can be quickly raised using the lifting cylinder without disassembling the equipment, significantly reducing maintenance difficulty and time costs. Furthermore, the lifting cylinder can adjust the height of the granulation roller to flexibly handle fluctuations in the amount of molten slag (e.g., raising the roller to prevent jamming when the slag layer is too thick), enhancing the system's adaptability to production conditions. Finally, after descending, the granulation roller cooperates with the moving bed to ensure a sealed space is formed inside the granulation hood, preventing high-temperature flue gas leakage while maintaining the waste heat recovery efficiency of the jet nozzle.

[0031] Continue to refer to Figure 1 The granulation hood 2 is equipped with a switch door 9 above the track 8; wherein, When the opening and closing door 9 is raised, the moving bed 3 can move in and out of the granulation hood 2 along the track; when the opening and closing door 9 is closed, the granulation hood 2 forms a sealed space. The opening and closing door 9 can be raised and lowered by a winch or a hydraulic cylinder.

[0032] The molten metallurgical slag granulation and waste heat recovery system of this invention uses a winch or hydraulic cylinder to drive the opening and closing of the granulation hood. The hood can be quickly opened when the moving bed enters or exits the granulation hood and tightly closed during operation, ensuring a closed space inside the granulation hood to prevent the leakage of high-temperature flue gas and dust, thus meeting environmental protection requirements. After the opening and closing of the hood, the airtightness of the granulation hood maintains a stable circulation path for the high-temperature flue gas inside, preventing heat loss, improving the heat exchange efficiency between the jet nozzle and the waste heat boiler, and maximizing the recovery of the sensible heat of the molten slag. The linkage control of the opening and closing of the hood with the track movement of the moving bed and the lifting of the granulator achieves fully automated connection of the "slag receiving-granulation-unloading" process, reducing manual intervention and improving the continuity of system operation. When the opening and closing of the hood is closed, the high-temperature molten slag processing process is isolated within the sealed hood, preventing operators from coming into contact with high temperatures or splashing molten slag, significantly improving safety.

[0033] Continue to refer to Figure 1 A hopper 10 is provided below the granulator 1 and the moving bed 3. A feeder 11 is installed at the bottom of the hopper 10 to uniformly convey the material to the conveyor 13 below.

[0034] The granulation and waste heat recovery system for molten metallurgical slag in this embodiment of the invention has a silo located directly below the granulator and moving bed. This silo can directly receive the granulated solid metallurgical slag and uniformly convey it to the conveyor via a bottom feeder (such as a vibrating feeder or screw feeder), forming an integrated "granulation-collection-transfer" process. This avoids the inefficiency of manual slag cleaning in traditional processes. The silo, granulation hood, and moving bed form a closed connection to prevent dust from escaping during granulation. Combined with a dust removal device, this further reduces environmental pollution and meets environmental emission standards.

[0035] Continue to refer to Figure 1 The flue gas jet nozzle 5 is arranged in parallel with the granulation roller. The flue gas jet nozzle 5 consists of one or more rows of nozzles. The bottom of the nozzle is higher than the low baffle of the moving bed. The upper end of the nozzle is connected to the circulating fan 7 through pipes.

[0036] The molten metallurgical slag granulation and waste heat recovery system of this invention features a nozzle bottom higher than the moving bed baffle, ensuring that the jet flue gas can uniformly cover the surface of the molten metallurgical slag for direct and efficient heat exchange, maximizing waste heat recovery efficiency. The multi-row nozzle design allows for flexible adjustment of the number of nozzles and airflow intensity based on the amount and temperature distribution of the metallurgical slag, adapting to different operating conditions. The nozzle height setting avoids interference with the moving bed baffle or granulated slag, while reducing the risk of nozzle clogging due to slag splashing. The nozzles are directly connected to the circulating fan via pipelines, forming a closed-loop system, reducing heat loss and improving the steam output stability of the waste heat boiler. This design, through precise fluid control and structural layout, achieves synergistic optimization of metallurgical slag cooling and waste heat recovery, combining high efficiency and reliability.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A molten metallurgical slag granulation and waste heat recovery system, characterized by, The system comprises a molten metallurgical slag granulation device and a waste heat recovery device; wherein, The molten metallurgical slag granulation device comprises a granulator, a granulation bed and a granulation cover; the granulator comprises a granulation roller and a granulator driving device; the granulation bed comprises a moving bed and a granulation bed driving device in transmission connection with the moving bed, and the granulation bed driving device is used to drive the moving bed to reciprocate between a slag receiving position outside the granulation cover and a granulation position inside the granulation cover; The waste heat recovery device comprises a flue gas jet pipe, a waste heat boiler, a dust removal device and a circulating fan; the flue gas jet pipe is fixed inside the granulation cover, the air outlet of the granulation cover is connected with the dust removal device, the dust removal device is connected with the waste heat boiler through an air pipe, the inlet of the circulating fan is connected with the waste heat boiler, and the outlet of the circulating fan is connected with the flue gas jet pipe.

2. The smelting slag granulation and waste heat recovery system of claim 1, wherein, Low baffle plates are arranged at both ends of the moving bed along the moving direction of the moving bed, and high baffle plates are arranged at the other two ends; When the moving bed moves to the position where the granulator contacts the low baffle plates, the granulator and the moving bed both start to operate reversely.

3. The smelting slag granulation and waste heat recovery system of claim 1, wherein, Wheels are arranged at the bottom of the moving bed, and a track is arranged to support the wheels; The granulation bed driving device comprises a driving motor, a transmission gear and a transmission rack; the transmission gear is in transmission connection with the output shaft of the driving motor and is in meshing connection with the transmission rack; and the transmission rack is fixedly connected with the wheels.

4. The smelting slag granulation and waste heat recovery system of claim 3, wherein, The first end of the track is located outside the granulation cover and corresponds to the slag receiving position, and the second end of the track extends into the granulation cover and corresponds to the position below the slag outlet of the metallurgical furnace.

5. The smelting slag granulation and waste heat recovery system of any one of claims 1 to 4, wherein, A lifting oil cylinder is arranged in the bearing seat of the granulator; The piston rod of the lifting oil cylinder is fixedly connected with the granulation roller to drive the granulation roller to lift and descend so that the moving bed moves out of the bottom of the granulation roller.

6. The smelting slag granulation and waste heat recovery system of any one of claims 1 to 4, wherein, A switch door is arranged above the track on the granulation cover; wherein, When the switch door is lifted, the moving bed can enter and exit the granulation cover along the track; and when the switch door is closed, the granulation cover forms a sealed space.

7. The smelting slag granulation and waste heat recovery system of claim 6, wherein, The switch door is lifted and lowered by a winch or a hydraulic oil cylinder.

8. The smelting slag granulation and waste heat recovery system of any one of claims 1 to 4, wherein, A stock bin is arranged below the granulator and the moving bed, and a feeder is arranged at the bottom of the stock bin to uniformly feed the material to the lower conveyor.

9. The smelting slag granulation and waste heat recovery system of any one of claims 1 to 4, wherein, The flue gas jet pipe is arranged in parallel with the granulation roller; the flue gas jet pipe is one row or multiple rows of jet pipes, the bottom of the jet pipe is higher than the low baffle plate of the moving bed, and the upper end of the jet pipe is connected with the circulating fan through a pipe.

10. The smelting slag granulation and waste heat recovery system of any one of claims 1 to 4, wherein, Dry solid metallurgical slag is laid in the moving bed.

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