CN117867193A - System and method for cooling and granulating molten metallurgical slag - Google Patents

System and method for cooling and granulating molten metallurgical slag Download PDF

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Publication number
CN117867193A
CN117867193A CN202311661508.1A CN202311661508A CN117867193A CN 117867193 A CN117867193 A CN 117867193A CN 202311661508 A CN202311661508 A CN 202311661508A CN 117867193 A CN117867193 A CN 117867193A
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China
Prior art keywords
granulating
particle
slag
cooling
chamber
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CN202311661508.1A
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Chinese (zh)
Inventor
田京雷
孟立宁
李毅仁
孙宇佳
王博
李国涛
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HBIS Co Ltd
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HBIS Co Ltd
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Priority to CN202311661508.1A priority Critical patent/CN117867193A/en
Publication of CN117867193A publication Critical patent/CN117867193A/en
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B3/00—General features in the manufacture of pig-iron
    • C21B3/04—Recovery of by-products, e.g. slag
    • C21B3/06—Treatment of liquid slag
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B3/00—General features in the manufacture of pig-iron
    • C21B3/04—Recovery of by-products, e.g. slag
    • C21B3/06—Treatment of liquid slag
    • C21B3/08—Cooling slag
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/004—Systems for reclaiming waste heat
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2400/00—Treatment of slags originating from iron or steel processes
    • C21B2400/02—Physical or chemical treatment of slags
    • C21B2400/022—Methods of cooling or quenching molten slag
    • C21B2400/026—Methods of cooling or quenching molten slag using air, inert gases or removable conductive bodies
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2400/00—Treatment of slags originating from iron or steel processes
    • C21B2400/04—Specific shape of slag after cooling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2400/00—Treatment of slags originating from iron or steel processes
    • C21B2400/05—Apparatus features
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2400/00—Treatment of slags originating from iron or steel processes
    • C21B2400/08—Treatment of slags originating from iron or steel processes with energy recovery
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacture Of Iron (AREA)
  • Furnace Details (AREA)

Abstract

The invention discloses a cooling granulating system and a method for molten metallurgical slag, wherein the cooling granulating system comprises a sedimentation granulating chamber, a granulator nozzle, a liquid slag buffer tank, a particle bin, a particle mixer, a particle reinforced conveying fan, a primary granulating fan, a baffling pre-dedusting device, a secondary pre-dedusting device, a fixed bed heat exchanger and the like; the outlet of the granulator nozzle stretches into the inner cavity of the sedimentation granulating chamber; the molten metallurgical slag in the liquid slag buffer tank flows into the sedimentation granulating chamber and forms liquid slag waterfall flow, and the injection direction of the nozzle outlet of the granulator is opposite to the liquid slag waterfall flow; the particle mixer is communicated with an outlet at the lower part of the particle bin, and the particle reinforced conveying fan is communicated with the particle mixer and then is communicated with an inlet of a nozzle of the granulator; the primary granulating fan is communicated with the inlet of the granulator nozzle; the air outlet of the sedimentation granulating chamber is communicated with the dust removing device, and the powder outlet of the dust removing device is communicated with the feeding port of the granule bin. The system and the method achieve the effects of rapid cooling and uniform quenching.

Description

System and method for cooling and granulating molten metallurgical slag
Technical Field
The invention relates to a metallurgical waste recycling method, in particular to a molten metallurgical slag cooling granulating system and a method.
Background
In the beginning of the 80 s of the 20 th century in China, a blast furnace slag wind quenching method is researched, a saddle mountain steel mill inputs wind quenching treatment equipment in 2007, and obtained slag particles finally fall into a water tank to be cooled, so that the method is actually combined with a water quenching method. It is reported that crystallization behavior occurs during air quenching, fibers are easily generated and then the equipment is blocked, and the gas-slag heat exchange is reduced. Researches show that when the grain diameter is smaller and the grain diameter distribution is more uniform, the heat exchange effect is better, the waste heat recovery efficiency is higher, the cooling speed is faster, and the glass phase content is higher. Therefore, the granulating performance directly determines the subsequent utilization of slag particles and waste heat recovery, but the research on the granulating performance of blast furnace slag is not reported at present. Meanwhile, the recovery efficiency of the blast furnace slag waste heat recovery exergy is very low, and the recovery efficiency of exergy is only about 40% although the heat recovery efficiency of industrial experiments is above 60% and even more than 80%, which indicates that the quality of the recovered waste heat is lower.
The domestic scientific workers also explore a roller granulating method, a rotary cup or a rotary disc centrifugal granulating method; the roller method is characterized in that slag flows onto a continuously rotating roller to drive the slag to form a sheet shape to adhere to the slag, cooling fluid introduced into the slag is rapidly cooled to obtain solid slag with high glass rate, and heat energy recovered by scraping of a scraper is used for generating electricity. The method can ensure that the slag is quickly cooled to obtain the glass body, but has low processing capacity, low operation efficiency, large damage to the outer surface of the roller, large and flaky metallurgical slag particles, high crushing energy consumption and adverse effect on subsequent processing.
The centrifugal granulating method of the rotating cup or the rotating disc is that molten liquid slag flows into the rotating cup or the rotating disc, the slag is thrown out of the edge of the rotating cup or the rotating disc for granulating under the action of centrifugal force, and is cooled and falls down in the flying process, and hot air is obtained. The turntable of the method runs at high speed in a high-temperature environment, equipment is easy to break down, and the maintenance difficulty is very high, so that long-term stable operation is difficult to realize.
Realizing the granulating effect of metallurgical slag and the industrialized and economic operation of waste heat recovery, the technological process in the granulating process must be regulated and controlled, the granulating cooling rate and waste heat recovery process are optimized, and the granulating performance of the slag is improved; the problem that the recovery efficiency of blast furnace slag waste heat exergy is improved and high added value granule particles are produced simultaneously is the key solution at present.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a molten metallurgical slag cooling and granulating system for producing slag particles with uniform and high crystal rate; the invention also provides a cooling granulating method of the melting metallurgical slag.
In order to solve the technical problems, the technical scheme adopted by the system is as follows: the device comprises a sedimentation granulating chamber, a granulator nozzle, a liquid slag buffer tank, a particle bin, a particle mixer, a particle reinforced conveying fan, a primary granulating fan, a baffling pre-dust removing device and a secondary pre-dust remover; the outlet of the granulator nozzle stretches into the inner cavity of the sedimentation granulating chamber; the molten metallurgical slag in the liquid slag buffer tank flows into the sedimentation granulating chamber and forms liquid slag waterfall flow, and the injection direction of the nozzle outlet of the granulator is opposite to the liquid slag waterfall flow; the particle mixer is communicated with an outlet at the lower part of the particle bin, and the particle reinforced conveying fan is communicated with the particle mixer and then is communicated with an inlet of a nozzle of the granulator; the primary granulating fan is communicated with the inlet of the granulator nozzle; the air outlet of the sedimentation granulating chamber is communicated with the dust removing device, and the powder outlet of the dust removing device is communicated with the feeding port of the granule bin.
Further, the inner cavity of the sedimentation and granulation chamber comprises a primary sedimentation chamber and a secondary sedimentation chamber; the granulator nozzle is communicated with the front part of the primary granulating and settling chamber, and molten metallurgical slag in the liquid slag buffer tank forms liquid slag waterfall flow in the primary granulating and settling chamber; the secondary granulating and settling chamber is positioned at the rear part of the primary granulating and settling chamber, and the rear part of the secondary granulating and settling chamber is provided with an inclined plate cold wall which is inclined towards the front lower part.
Further, the lower part of the secondary granulating and settling chamber is provided with a cooling buried pipe.
Further, the lower outlet of the secondary granulating and settling chamber is communicated with a small-particle fluidized bed heat exchanger through a small-particle slag discharging screw.
Furthermore, the outlet of the lower part of the primary granulating and settling chamber is communicated with a large-particle fixed bed heat exchanger through a large-particle slag extractor.
The method adopts the system, and comprises the following steps: 1) The molten metallurgical slag flows into a sedimentation granulating chamber and forms a liquid slag waterfall flow; simultaneously, the primary granulating fan sends granulating airflow to the granulator nozzle, and the airflow of the granule strengthening conveying fan carries cold metallurgical slag granules to form mixed powder airflow after passing through the granule mixer and enters the granulator nozzle;
2) The granulating air flow and the mixed powder air flow are mixed in a nozzle of the granulator and then sprayed to the liquid slag waterfall flow, and the molten metallurgical slag is granulated under the high-speed impact of the air flow; when the cold metallurgical slag particles impact the molten metallurgical slag, the molten metallurgical slag wraps the cold metallurgical slag particles, and the cold metallurgical slag particles are granulated into hot metallurgical slag particles and sprayed into a sedimentation granulating chamber;
3) The thermal state metallurgical slag particles are settled in a settling granulating chamber;
4) And the hot flue gas in the sedimentation granulating chamber is dedusted by a dedusting device, and the generated powder enters a particle bin to be used as cold metallurgical slag particles.
Further, in the step 3), large particles in the hot metallurgical slag particles are settled in a primary granulating and settling chamber, and small particles are settled in a secondary granulating and settling chamber.
Furthermore, large particles in the thermal state metallurgical slag particles are settled and then enter a large particle fixed bed heat exchanger for heat exchange and cooling, and small particles are settled and then enter a small particle fluidized bed heat exchanger for heat exchange and cooling.
The beneficial effects of adopting above-mentioned technical scheme to produce lie in: in the wind quenching and granulating process of the molten metallurgical slag, cold metallurgical slag particles recovered by the molten metallurgical slag are mixed in wind power to form reinforced wind quenching, so that the rapid cooling and uniform cooling quenching effects are achieved. The invention ensures that the molten slag is cooled extremely fast to form uniform particles of the glass body, and effectively realizes the recycling of blast furnace slag.
According to the invention, waste heat recovery is carried out on the flue gas and the metallurgical slag particles after wind quenching, so that the heat energy recovery is carried out in steps in different modes of gas-gas heat exchange, gas-solid heat exchange, gas-water heat exchange and the like, the utilization rate and the waste heat recovery efficiency of slag particles with high quality, low cost and no secondary pollution are realized, the manufacturing cost and the operation cost of equipment are reduced, and an effective method is provided for energy conservation, consumption reduction and carbon reduction in the metallurgical industry.
The invention uses low-temperature circulating smoke or other low-temperature smoke ratio to directly cool air by a fan, thereby reducing the kinetic energy of the fan and reducing the energy consumption; the inert oxygen content of the flue gas is lower than 8%, so that the oxidation of components in slag is reduced, and the glass body rate and the product quality of slag particles are improved.
Drawings
The invention will be described in further detail with reference to the drawings and the detailed description.
FIG. 1 is a schematic diagram of the structure of the present invention;
fig. 2 is a schematic diagram of the positional relationship between the granulator nozzle and the waterfall flow of liquid slag according to the present invention.
In the figure: 1. a primary granulating fan; 2. a granulator nozzle; 3. a liquid slag buffer tank; 4. a primary granulating and settling chamber; 5. a cooling cap; 6. a secondary granulating and settling chamber; 7. a sloping plate cold wall; 8. cooling the buried pipe; 9. small particle slag discharging spiral; 10. a large particle slag extractor; 11. a secondary pre-deduster; 12. a circulating water pump; 13. a water-cooled heat exchanger; 14. a small particle fluidized bed heat exchanger; 15. a secondary cooling fan; 16. a large particle fixed bed heat exchanger; 17. a particle reinforced conveying fan; 18. a particle bin; 19. a particle mixer; 20. high temperature flue gas; 21. a finished product of the hot metallurgical slag small particles; 22. a finished product of the hot metallurgical slag large particles; 23. a baffling pre-dust removal device; 24. a sedimentation granulating chamber; 25. a semi-partition baffle; 26. a particle spiral discharger; 27. sizing and speed-fixing device; 28. a liquid slag waterfall flow; 29. and a diversion trench.
Detailed Description
As shown in FIG. 1, the cooling and granulating system for the molten metallurgical slag comprises a sedimentation and granulating chamber 24, a granulator nozzle 2, a liquid slag buffer tank 3, a particle bin 18, a particle mixer 19, a particle reinforced conveying fan 17, a primary granulating fan 1, a baffling pre-dust removing device 23, a secondary pre-dust remover 11, a small particle fluidized bed heat exchanger 14 and a large particle fixed bed heat exchanger 16. As shown in fig. 2, a diversion trench 29 is arranged at the bottom of the liquid slag buffer tank 3, a sizing and speed-fixing device 27 is arranged at the lower part of the diversion trench 29, and the sizing and speed-fixing device 27 is positioned at the front part of the sedimentation granulating chamber 24 and is communicated with the interior of the sedimentation granulating chamber; thus, the molten metallurgical slag in the liquid slag buffer tank 3 can flow into the sizing and speed-fixing device 27 through the diversion trench 29, and flow into the granulating chamber through the sizing and speed-fixing device 27 to form a liquid slag waterfall flow 28 like a waterfall. The granulator nozzle 2 is arranged at the front end of the sedimentation granulation chamber, the outlet of the granulator nozzle extends into the front end of the inner cavity of the sedimentation granulation chamber, and the spraying direction is opposite to the liquid slag waterfall flow 28. The granulator nozzle 2 is provided with two channels, namely a central channel and an annular channel; the primary granulation fan 1 is communicated with the inlet of the annular channel of the granulator nozzle 2 and is used for providing high-pressure injection power. The particle mixer 19 is communicated with the lower outlet of the particle bin 18, and the particle reinforced conveying fan 17 is communicated with the particle mixer 19 and then is communicated with the inlet of the central channel of the granulator nozzle 2. In this way, cold metallurgical slag particles in the particle bin 18 enter the particle mixer 19 to meet and mix with the air flow generated by the particle reinforced conveying fan 17 to form mixed powder air flow carrying the cold metallurgical slag particles; the primary granulating fan 1 generates granulating air flow, the mixed powder air flow and the granulating air flow enter the granulator nozzle 2 to be mixed and then are sprayed out of the inner cavity of the sedimentation granulating chamber 24, the sprayed mixed air flow impacts the liquid slag waterfall flow 28, and the molten metallurgical slag is granulated under the high-speed impact of the air flow; and when the cold metallurgical slag particles impact the molten metallurgical slag, the molten metallurgical slag wraps the cold metallurgical slag particles, is granulated into hot metallurgical slag particles and is sprayed into a sedimentation granulating chamber. The granulator nozzle 2 is designed with an adjustable angle, so that the spraying angle can be adjusted according to the flow speed of the liquid slag waterfall 28, the spraying length and the spraying height, and finally the residence time of the spraying on the upper part of the sedimentation granulation chamber 24 is adjusted, and the cooling effect is adjusted.
As shown in fig. 1, in the cooling and granulating system for molten metallurgical slag, a semi-blocking baffle 25 is arranged in the inner cavity of the sedimentation and granulating chamber 24, and the semi-blocking baffle 25 blocks the lower half part and the upper half part of the inner cavity of the sedimentation and granulating chamber 24. The semi-partition baffle 25 is positioned at the front part or the middle front part of the inner cavity of the sedimentation granulation chamber 24 and is used for semi-partitioning the inner cavity of the sedimentation granulation chamber 24 into a primary granulation sedimentation chamber 4 and a secondary granulation sedimentation chamber 6. The primary sedimentation granulating chamber 4 is used for recycling and secondary cooling some large particles in the hot metallurgical slag particles sprayed out of the granulator nozzle 2, and can also be used for recycling and cooling liquid slag which is not completely air-quenched when emergency power is off or equipment fails; a hopper is arranged at the bottom of the primary granulating and settling chamber 4, a cooling cap 5 is arranged above the hopper, and a lower outlet is arranged at the bottom; the cooling cap 5 is of a conical structure, adopts a hollow structure, and can be communicated with cooling water and cold water wind so as to realize a better cooling effect; the large-particle hot metallurgical slag particles slide off the outer surface of the cooling cap 5 during the falling process and are cooled by the cooling cap 5 during the sliding process. The lower outlet of the primary granulating and settling chamber 4 is provided with a large-particle slag extractor 10, and the large-particle slag extractor 10 is communicated with a large-particle fixed bed heat exchanger 16; thus, the large-particle hot metallurgical slag particles which are settled by the primary granulating and settling chamber 4 and secondarily cooled by the cooling cap 5 are sent into the large-particle fixed bed heat exchanger 16 by the large-particle slag extractor 10, and the hot metallurgical slag large-particle finished product 22 is obtained after heat exchange and cooling.
As shown in fig. 1, in the secondary granulating and settling chamber 6 of the settling and granulating chamber 24 of the molten metallurgical slag cooling and granulating system, an inclined plate cold wall 7 is arranged at the rear end of the secondary granulating and settling chamber 6, and the inclined plate cold wall 7 is inclined towards the front lower side; the inclined plate cooling wall 7 can be cooled by water cooling or air cooling; as shown in fig. 1, water cooling is adopted, namely a cooling water passage is arranged in the inclined plate cooling wall 7, the upper outlet of the cooling water passage is communicated with a water cooling heat exchanger 13 and a circulating water pump 12, and the outlet of the circulating water pump 12 is communicated with the lower inlet of the cooling water passage, so that cooling water circulation is formed; after the inclined plate cooling wall 7 is adopted, small particles blown off from the hot metallurgical slag particles sprayed out by the granulator nozzle 2 fall onto the inclined plate cooling wall 7, slide downwards along with the inclined plate cooling wall 7 and are cooled secondarily. A hopper is arranged at the bottom of the secondary granulating and settling chamber 6, and a plurality of cooling buried pipes 8 are arranged above the hopper; thus, the thermal state metallurgical slag particles after secondary cooling by the inclined plate cold wall 7 are cooled by the cooling buried pipe 8 for three times and enter the hopper, and the temperature of the thermal state metallurgical slag particles is ensured to be reduced to below 300 ℃. A lower outlet of the secondary granulating and settling chamber 6 is arranged below the hopper; a small particle slag discharging spiral 9 is arranged at the lower outlet and is communicated with a small particle fluidized bed heat exchanger 14 through the small particle slag discharging spiral 9; thus, the small-sized hot metallurgical slag particles which are subjected to sedimentation in the secondary granulating and settling chamber 6, secondary cooling in the inclined plate cooling wall 7 and tertiary cooling in the cooling buried pipe 8 are sent into the small-sized fluidized bed heat exchanger 14 through the small-sized slag discharging spiral 9, and the small-sized hot metallurgical slag finished product 21 is obtained after heat exchange and cooling.
As shown in fig. 1, in the cooling and granulating system for molten metallurgical slag, the small-particle fluidized bed heat exchanger 14 and the large-particle fixed bed heat exchanger 16 adopt air cooling structures, air cooling channels are arranged in the pipe walls of the small-particle fluidized bed heat exchanger 14 and the large-particle fixed bed heat exchanger 16, and the two air cooling channels are provided with a lower air inlet and an upper air outlet; the secondary cooling fan 15 is arranged, and an air outlet of the secondary cooling fan 15 is respectively communicated with a lower air inlet of an air cooling channel of the small-particle fluidized bed heat exchanger 14 and a lower air inlet of an air cooling channel of the large-particle fixed bed heat exchanger 16; the upper air outlet of the air cooling channel of the small-particle fluidized bed heat exchanger 14 and the upper air outlet of the air cooling channel of the large-particle fixed bed heat exchanger 16 are respectively communicated with the cooling buried pipe 8 in the hopper of the primary granulating and settling chamber 4 and the cooling buried pipe 8 in the secondary granulating and settling chamber 6 after being converged; in this way, the cooling air is respectively sent into the small-particle fluidized bed heat exchanger 14 and the large-particle fixed bed heat exchanger 16 by the secondary cooling fan 15 for heat exchange and then is divided into two paths, one path of cooling air enters the hopper of the primary granulating and settling chamber 4 for upward blowing, and the upward cooling air can also be used for primarily cooling liquid slag while cooling the cooling cap; the other path of the cooling water enters the cooling buried pipes 8, the cooling buried pipes 8 are arranged into a multi-row and multi-layer structure, a plurality of or a plurality of rows of cooling ports are arranged at the bottom of each cooling buried pipe, the cooling water is sprayed downwards, and the cooling water enters the granulating and settling chamber to cool the granulated particles again.
As shown in fig. 1, the rear top of the sedimentation granulating chamber 24 of the molten metallurgical slag cooling granulating system is provided with an air outlet which is provided with a communicating dust removing device; the dust removing device comprises a baffling pre-dust removing device 23 and a secondary pre-dust remover 11; the baffling pre-dedusting device 23 is communicated with the upper part of the air outlet of the sedimentation granulating chamber 24, is of a tubular structure, and is internally provided with an inclined inward downward baffling baffle; thus, when the hot flue gas in the sedimentation granulation chamber flows upwards through the baffling pre-dedusting device 23, the baffling baffle collides with particles contained in the hot flue gas, and the particles fall down through gravity to be settled and return to the secondary granulation sedimentation chamber 6, so that the guiding-out of the high-temperature flue gas and the recycling of the particles in the flue gas are ensured, and cleaner hot flue gas is ensured to be discharged. The air outlet of the baffling pre-dust-removing device 23 is communicated with the secondary pre-dust remover 11, and a cyclone dust remover is adopted most; in this way, the cleaner hot flue gas is discharged and enters the secondary pre-dust collector 11 to carry out secondary pre-dust removal, and the formed high-temperature flue gas 20 meets the requirements of a waste heat boiler or a hot blast stove or is integrated into a high-temperature power generation system pipe network. The powder outlet of the secondary pre-deduster 11 is communicated with the feed inlet of the particle bin 18 through a particle spiral discharger 26; the metallurgical slag particles collected in the flue gas particle settling chamber of the secondary pre-dust collector 11 are conveyed to the particle bin 18 through the particle screw discharger 26 as cold metallurgical slag particles.
The cooling and granulating method of the melting metallurgical slag adopts a coupling technical route of 'wind quenching cooling, cold nuclear hot skin particle strengthening, fluidized bed and flue gas circulation' and a cascade heat energy recovery process; the process flow is as follows:
the molten metallurgical slag flows into the sedimentation granulating chamber 24 from the bottom of the liquid slag buffer tank 3 through the sizing and speed-fixing device 27, and forms a liquid slag waterfall flow 28 above the primary granulating and sedimentation chamber; simultaneously, the wind power output by the primary granulating fan 1 inputs granulating air flow to the granulator nozzle 2, the mixed powder air flow is input to the granulator nozzle 2 through the particle mixer 19 in cooperation with the wind power of the particle strengthening conveying fan 17, and the granulating air flow and the mixed powder air flow are mixed and sprayed out of the granulator nozzle 2 to form the strengthened high-speed mixed air flow containing particles in two phases of gas and solid; the sprayed mixed air flow is sprayed onto the liquid slag waterfall flow 28 to impact the molten metallurgical slag; the molten metallurgical slag is granulated into metallurgical slag particles under the high-speed impact of the mixed air flow containing particles, when the cold metallurgical slag particles in the high-speed mixed air flow impact the molten metallurgical slag, the hot molten metallurgical slag wraps the cold metallurgical slag particles, the contact area between the hot molten metallurgical slag particles and the cold metallurgical slag particles is increased, the process of rapid cooling and heat exchange between the cold metallurgical slag particles and the hot molten metallurgical slag wrapped outside is realized, and therefore the molten metallurgical slag particles enter the primary granulating and settling chamber 4 and the secondary granulating and settling chamber 6 to perform cascade cooling and heat exchange, and meanwhile, heat energy is recovered in a cascade mode. The cooling method is called cold core hot skin, and the principle is as follows: the process of remolding the hot slag into cold nuclear hot skin wrapping cold particles after the liquid slag is quickly dispersed by high-pressure airflow; the surface area of contact under the state of the cold core and the hot shell is increased, so that the particle cooling and heating heat exchange efficiency can be accelerated to cool down the particle uniformly and rapidly, the uniform glass crystal particle is produced by rapid cooling of slag granulation, and conditions are created for subsequent high-value recovery of solid particles to produce cement.
The molten metallurgical slag is blown off by a quenching method of cold nuclear hot skin and then is subjected to secondary cooling in a primary sedimentation granulating chamber 4 and a secondary sedimentation granulating chamber 6: the primary sedimentation granulating chamber 4 recovers and cools liquid slag which is not completely air-quenched when large particles or emergency power failure or equipment failure occurs; a water cooling wall or an air cooling device is arranged in the primary sedimentation granulating chamber 4 to forcedly cool large particles or liquid slag which is not completely air quenched; the secondary sedimentation granulation chamber 6 is a process of carrying out secondary cooling heat exchange on blown-off particles, the blown-off particles fall on a water cooling wall 7 or an air cooling wall inclined plane 7 of the secondary sedimentation granulation chamber 6 for cooling heat exchange, and simultaneously the particles after secondary cooling naturally fall to a hopper at the bottom of the secondary sedimentation granulation chamber 6 along with the cooling wall inclined plane 7 for collection; the bottom hopper is simultaneously provided with a bottom three-time cooling air buried pipe 8 or a water cooling wall pipe for three-time cooling of the flowing particles, so that the slag discharging temperature is ensured to be reduced below 300 ℃.
And the waste heat recovery process of the high-temperature flue gas generated in the air quenching and secondary and tertiary cooling processes comprises the following steps: the air quenching cooling air and the secondary tertiary cooling air are mixed in the primary sedimentation granulating chamber 4 and the secondary sedimentation granulating chamber 6 and then discharged, a pre-dedusting device which is formed by at least a hot flue gas outlet, a hot flue gas particle baffle plate 23, a hot flue gas particle sedimentation recycling chamber and the like is arranged at the top of the secondary sedimentation granulating chamber 6, particles contained in hot flue gas collide with the baffle plate and fall down to the flue gas particle sedimentation chamber through gravity, so that the guiding of high-temperature flue gas and the recycling of particles in the flue gas are ensured, and cleaner hot flue gas discharge is ensured; the cleaner hot flue gas is discharged and enters the secondary pre-deduster 11 to carry out secondary pre-dedusting, and the high-temperature flue gas 20 reaches a waste heat boiler or a hot blast stove or is integrated into a high-temperature power generation system pipe network. The metallurgical slag particles collected by the flue gas particle settling chamber of the secondary pre-dust collector are conveyed to a particle bin 18 through a particle spiral discharger 26, and are circulated to a cold core hot skin cooling process through a particle reinforced conveying fan 17 through a particle mixer 19.
Collecting and waste heat recovery process of large-particle slag from the primary sedimentation granulation chamber 4 and small-particle slag from the secondary sedimentation physicochemical chamber 7: the large-particle slag in the primary sedimentation granulation chamber 4 is conveyed to a sealed large-particle fixed bed heat exchanger 16 through a high Wen Dou extraction or large-particle slag extractor 10 to exchange heat with cooling air or low-temperature circulating waste gas; the small-particle slag in the secondary granulating and settling chamber 6 is conveyed to a small-particle fluidized bed heat exchanger 14 through a high Wen Dou extraction or small-particle slag discharging spiral 9 to exchange heat with cooling air or low-temperature circulating waste gas; the small particle fluidized bed heat exchanger 14 is provided with a plurality of layers of inclined baffle plates with holes or transversely arranged calandria with cooling water introduced into the inside; the small slag particles collide with the inclined multi-layer baffle plates or the cooling water discharge pipes to turn back and flow in the falling process, exchange heat with the cooling air reversely arranged at the bottom, discharge high-temperature air or high-temperature hot water or steam and recycle the high-temperature air or the high-temperature hot water or steam.
Meanwhile, the low-temperature circulating smoke or other low-temperature smoke after gas-solid heat exchange is used as hot inert gas for cyclic utilization, so that compared with the direct use of cold air of a fan, the kinetic energy of the fan is reduced, and the energy consumption is reduced; the inert oxygen content of the flue gas is lower than 8%, so that the oxidation of components in slag is reduced, and the glass body rate and the product quality of slag particles are improved.

Claims (8)

1. A molten metallurgical slag cooling and granulating system, characterized in that: the device comprises a sedimentation granulating chamber (24), a granulator nozzle (2), a liquid slag buffer tank (3), a particle bin (18), a particle mixer (19), a particle reinforced conveying fan (17), a primary granulating fan (1), a baffling pre-dedusting device (23) and a secondary pre-deduster (11); the outlet of the granulator nozzle (2) stretches into the inner cavity of the sedimentation granulating chamber; the molten metallurgical slag in the liquid slag buffer tank (3) flows into the sedimentation granulating chamber (24) and forms a liquid slag waterfall flow (28), and the blowing direction of the outlet of the granulator nozzle (2) is opposite to the liquid slag waterfall flow (28); the particle mixer (19) is communicated with the lower outlet of the particle bin (18), and the particle reinforced conveying fan (17) is communicated with the particle mixer (19) and then is communicated with the inlet of the granulator nozzle (2); the primary granulating fan (1) is communicated with the inlet of the granulator nozzle (2); the air outlet of the sedimentation granulating chamber (24) is communicated with a dust removing device, and the powder outlet of the dust removing device is communicated with the feed inlet of the granule bin (18).
2. A molten metallurgical slag cooling and granulating system as claimed in claim 1, wherein: the inner cavity of the sedimentation and granulation chamber (24) comprises a primary granulation sedimentation chamber (4) and a secondary granulation sedimentation chamber (6); the granulator nozzle (2) is communicated with the front part of the primary granulating and settling chamber (4), and molten metallurgical slag in the liquid slag buffer tank (3) forms a liquid slag waterfall flow (28) in the primary granulating and settling chamber (4); the secondary granulating and settling chamber (6) is positioned at the rear part of the primary granulating and settling chamber (4), the rear part of the secondary granulating and settling chamber (6) is provided with an inclined plate cold wall (7), and the inclined plate cold wall (7) is inclined towards the front lower part.
3. A molten metallurgical slag cooling and granulating system as claimed in claim 1, wherein: the lower part of the secondary granulating and settling chamber (6) is provided with a cooling buried pipe (8).
4. A molten metallurgical slag cooling and granulating system as claimed in claim 1, wherein: the lower outlet of the secondary granulating and settling chamber (6) is communicated with a small-particle fluidized bed heat exchanger (14) through a small-particle slag discharging spiral (9).
5. A molten metallurgical slag cooling granulating system as claimed in any one of claims 1-4, wherein: the lower outlet of the primary granulating and settling chamber (4) is communicated with a large-particle fixed bed heat exchanger (16) through a large-particle slag extractor (10).
6. A method for cooling and granulating molten metallurgical slag using the system according to any one of claims 1 to 5, characterized by the steps of: 1) The molten metallurgical slag flows into a settling granulation chamber (24) and forms a liquid slag waterfall stream (28); simultaneously, the primary granulating fan (1) sends granulating airflow to the granulator nozzle (2), and the airflow of the granule strengthening conveying fan (17) carries cold metallurgical slag granules to form mixed powder airflow after passing through the granule mixer (19) and enters the granulator nozzle (2);
2) The granulating air flow and the mixed powder air flow are mixed in a granulator nozzle (2) and then sprayed to a liquid slag waterfall flow (28), and the molten metallurgical slag is granulated under the high-speed impact of the air flow; when the cold metallurgical slag particles impact the molten metallurgical slag, the molten metallurgical slag wraps the cold metallurgical slag particles, and the cold metallurgical slag particles are granulated into hot metallurgical slag particles and sprayed into a sedimentation granulating chamber;
3) The thermal state metallurgical slag particles are settled in a settling granulation chamber (24);
4) And the hot flue gas in the sedimentation granulating chamber (24) is dedusted by a dedusting device, and the generated powder enters a particle bin (18) to be used as cold metallurgical slag particles.
7. The method for cooling and granulating molten metallurgical slag according to claim 6, wherein: in the step 3), large particles in the hot metallurgical slag particles are settled in a primary granulating and settling chamber (4), and small particles are settled in a secondary granulating and settling chamber (6).
8. The method for cooling and granulating molten metallurgical slag as claimed in claim 7, wherein: and large particles in the thermal state metallurgical slag particles are settled and then enter a large particle fixed bed heat exchanger (16) for heat exchange and cooling, and small particles are settled and then enter a small particle fluidized bed heat exchanger (14) for heat exchange and cooling.
CN202311661508.1A 2023-12-06 2023-12-06 System and method for cooling and granulating molten metallurgical slag Pending CN117867193A (en)

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CN202311661508.1A CN117867193A (en) 2023-12-06 2023-12-06 System and method for cooling and granulating molten metallurgical slag

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CN202311661508.1A CN117867193A (en) 2023-12-06 2023-12-06 System and method for cooling and granulating molten metallurgical slag

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CN117867193A true CN117867193A (en) 2024-04-12

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