Steel slag modification and particle size treatment f-cao digestion device and method

Abstract

The application belongs to the technical field of steel slag digestion, and specifically discloses a f-CaO digestion device and method for steel slag modification and particle size treatment, which comprises a modifier pretreatment module, a steel slag modification module, a steel slag cooling and crushing module and a steel slag fluidized bed screening and digestion module. The modifier pretreatment module is used for pretreating and conveying the modifier. The steel slag modification module is used for modifying molten steel slag by using the pretreated modifier. The steel slag cooling and crushing module is used for crushing the modified steel slag and recovering waste heat. The steel slag fluidized bed screening and digestion module is used for screening the steel slag and adopting different digestion modes for the steel slag with different particle sizes. The steel slag particle size is screened by the steel slag fluidized bed screening and digestion module, and the crushed steel slag is digested according to the particle size. The steel slag digestion process in the method can be continuously operated, so that the f-CaO digestion in the steel slag is more targeted and efficient.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steel slag digestion, and particularly relates to a f-CaO digestion device and method for steel slag modification and particle size treatment. BACKGROUND

[0002] The steel industry has a large amount of energy consumption and solid waste emissions. Converter steel slag is a byproduct in the steel production process, and its tapping temperature is 1450-1650 DEG C. The production of the converter steel slag is about 10wt%-15wt% of the crude steel production. The molten steel slag not only has huge heat but also has high utilization value. Using the steel slag as building materials is a feasible path to realize large-scale resource utilization of solid waste and protect the environment. However, due to the characteristics of the steelmaking process, the steel slag contains too high f-CaO, which can react with H2O in the air to generate Ca(OH)2, and the volume expansion is 98%, which causes poor volume stability of the steel slag, resulting in safety problems such as burst, cracking and the like of the steel slag cement and the steel slag concrete, increases the safety hazard of the building using the steel slag as building materials, and seriously restricts the large-scale utilization of the steel slag.

[0003] At present, most steel plants mainly use open hot splashing water cooling to cool or naturally cool the steel slag. After the temperature of the steel slag is reduced to 80-100 DEG C, the steel slag is transported to the steel slag yard for open-air storage. Some steel plants use shallow plate hot splashing method, tank method, granulation wheel water quenching method, roller method and air quenching method to treat the steel slag. At present, the more advanced one is the roller crushing-remaining heat pressure hot smelting process, which can realize the recovery of the remaining heat of the steel slag and the digestion treatment of f-CaO in the steel slag.

[0004] The existing process method for f-CaO digestion treatment of the steel slag has high required heat, and the intermittent digestion process has long digestion cycle, low efficiency and poor effect. The more advanced roller crushing-remaining heat pressure hot smelting process is also an intermittent treatment, and the digestion effect is not ideal. SUMMARY

[0005] The purpose of the present application is to provide a f-CaO digestion device and method for steel slag modification and particle size treatment, so as to solve the technical problems of long digestion cycle, low digestion efficiency and inability to continuously digest of the existing steel slag digestion technology.

[0006] In order to achieve the above purpose, the technical scheme is adopted as follows:

[0007] In a first aspect, the f-CaO digestion device for steel slag modification and particle size separation treatment comprises a modifier pretreatment module, a steel slag modification module, a steel slag cooling and crushing module, and a steel slag fluidized bed screening and digestion module.

[0008] Further improvement of the present application is that the modifier pretreatment module comprises a modifier storage bin, a modifier crushing device, and a modifier preheating device.

[0009] The steel slag modification module comprises a slag channel, a slag ladle, and a modification reactor.

[0010] The steel slag cooling and crushing module comprises a molten slag gas quenching and waste heat recovery device and a roller crushing and waste heat recovery device.

[0011] The steel slag fluidized bed screening and digestion module comprises a fluidized bed screening and digestion reactor, a second cyclone separator, a fluidized bed carbonation digestion reactor, and a carbonation pressure suppression device.

[0012] The discharge port of the modifier storage bin is connected to the feed port of the modifier crushing device, the discharge port of the modifier crushing device is connected to the feed port of the modifier preheating device, and the discharge pipeline of the modifier preheating device is arranged above the feed port of the modification reactor.

[0013] The slag channel is arranged obliquely above the slag ladle, the slag channel is used to introduce molten steel slag into the slag ladle for storage, the discharge port of the slag ladle is arranged above the feed port of the modification reactor, and the discharge port of the modification reactor is connected to the feed port of the molten slag gas quenching and waste heat recovery device.

[0014] The molten slag gas quenching and waste heat recovery device is provided with an air inlet for introducing low-temperature air, the discharge port of the molten slag gas quenching and waste heat recovery device is connected to the feed port of the roller crushing and waste heat recovery device, the roller crushing and waste heat recovery device is provided with a water inlet for introducing normal-temperature water, the first gas outlet of the roller crushing and waste heat recovery device is connected to the first air inlet of the fluidized bed carbonation digestion reactor, the second gas outlet of the roller crushing and waste heat recovery device is connected to the second air inlet of the fluidized bed screening and digestion reactor, and the discharge port of the roller crushing and waste heat recovery device is connected to the feed port of the fluidized bed screening and digestion reactor.

[0015] The bottom of the fluidized bed screening digestion reactor is provided with a first gas inlet for introducing steel plant flue gas or enriched carbon dioxide, the top of the fluidized bed screening digestion reactor is provided with a first discharge port, the first discharge port of the fluidized bed screening digestion reactor is connected with the feed inlet of a second cyclone separator, the second discharge port of the fluidized bed screening digestion reactor is connected with the feed inlet of a carbonation pressure relief device, the discharge port of the carbonation pressure relief device discharges aggregate digestion products, the discharge port of the second cyclone separator is connected with the second feed inlet of a fluidized bed carbonation digestion reactor, the gas outlet of the second cyclone separator is connected with the second gas inlet of the fluidized bed carbonation digestion reactor, and the discharge port of the fluidized bed carbonation digestion reactor discharges micro-slag digestion products.

[0016] Further improvement of the present application is that the steel slag cooling and crushing module further comprises a first cyclone separator, the gas inlet of the first cyclone separator is connected with the gas outlet of the molten slag gas quenching and waste heat recovery device, the first gas outlet of the first cyclone separator is connected with the gas inlet of the modifier preheating device, the second gas outlet of the first cyclone separator is connected with the discharge pipeline of the modifier preheating device, and the discharge port of the first cyclone separator is connected with the first feed inlet of the fluidized bed carbonation digestion reactor.

[0017] Further improvement of the present application is that the steel slag modification module further comprises a temperature control device, a compressed air valve and an air compressor.

[0018] The discharge pipeline of the modifier preheating device is provided with a modifier conveying valve.

[0019] The first gas outlet of the first cyclone separator and the gas inlet of the modifier preheating device are sequentially provided with a compressed air valve and an air compressor.

[0020] The temperature measuring end of the temperature control device is arranged in the modification reactor, the temperature control device is electrically connected with the modifier conveying valve, the modifier conveying valve is further electrically connected with the compressed air valve, and the temperature control device is used for monitoring the temperature in the modification reactor and controlling the flow of the modifier conveying valve and the compressed air valve.

[0021] Further improvement of the present application is that the steel slag cooling and crushing module further comprises a waste heat boiler, the first gas inlet of the waste heat boiler is connected with the gas outlet of the modifier preheating device, the second gas inlet of the waste heat boiler is connected with the third gas outlet of the first cyclone separator, and the waste heat boiler is further provided with a water inlet and an outlet.

[0022] Further improvement of the present application is that a plurality of first oscillators are uniformly arranged on the outer wall of the modifier preheating device, and a plurality of second oscillators are uniformly arranged on the outer wall of the roller crushing and waste heat recovery device.

[0023] The further improvement of the present application is that the second discharge port of the fluidized bed screening digestion reactor is connected with the feed ports of the carbonation pressure devices.

[0024] The further improvement of the present application is that the third cyclone separator is further included in the steel slag fluidized bed screening digestion module, the gas inlet of the third cyclone separator is connected with the gas outlet of the fluidized bed carbonation digestion reactor, the first gas outlet of the third cyclone separator is connected with the third gas inlet of the fluidized bed carbonation digestion reactor, and the second gas outlet of the third cyclone separator is connected with the first gas inlet of the carbonation pressure device.

[0025] The further improvement of the present application is that the top cover is arranged above the modification reactor, and a plurality of air spray guns are uniformly arranged above the modification reactor.

[0026] In the second aspect, a f-CaO digestion method for steel slag modification and particle size treatment includes the following steps:

[0027] The modifier is pretreated;

[0028] The pretreated modifier is subjected to a modification reaction with molten steel slag;

[0029] The molten steel slag after the modification reaction is crushed to obtain crushed steel slag;

[0030] The crushed steel slag is screened according to particle size into large-particle-size steel slag and micro slag, and the large-particle-size steel slag and the micro slag are subjected to different ways of digestion respectively.

[0031] Compared with the prior art, the present application at least has the following beneficial effects:

[0032] 1. The steel slag is screened according to particle size by the steel slag fluidized bed screening digestion module, the crushed steel slag is subjected to digestion according to particle size, the large-particle-size steel slag and the micro slag are subjected to different ways of treatment respectively, the steel slag digestion process in the method can be continuously operated, and the steel slag digestion is more targeted and efficient;

[0033] 2. The first cyclone separator utilizes the steel slag waste heat to provide energy for the preheating of the added modifier and the reaction with the liquid steel slag, so that the steel slag waste heat recovery is realized, the steel slag composition is adjusted, the steel slag performance is improved, and the f-CaO content in the steel slag is reduced from the source;

[0034] 3. The liquid steel slag is transported and stored by the slag channel and the slag ladle, so that the online modification of the steel slag is realized, and the high-temperature waste heat of the steel slag is fully utilized;

[0035] 4. The fluidized bed strengthens the mass transfer process in the steel slag digestion process, the bed layer has good heat transfer performance, and the continuous treatment of the steel slag is realized, and the efficiency is higher.

[0036] 5、The present application connects the fluidized bed screening digestion reactor with multiple carbonation pressure devices, when one carbonation pressure device works, the remaining carbonation pressure devices can be used for digestion, without waiting, continuous operation;

[0037] 6、The top cover 208 arranged above the modification reactor is closed after the modifier is sprayed into the flowing steel slag through the air lance, which has heat preservation effect, prevents a large amount of modifier from accumulating in the space above the modification reactor, improves the utilization rate of the modifier, and strengthens the mixing of the modifier and the steel slag.

[0038] 7、The f-CaO in the steel slag is digested by using water vapor and steel plant flue gas or enriched CO2 as reactants, which realizes permanent in-situ storage of the CO2 discharged by the steel plant. BRIEF DESCRIPTION OF DRAWINGS

[0039] The drawings accompanying the specification of the present application serve to provide further understanding of the present application, and the illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute improper limitations on the present application.

[0040] In the drawings:

[0041] Figure 1 It is a module structure schematic diagram of the f-CaO digestion device for steel slag modification and particle size treatment according to the present application;

[0042] Figure 2 It is a whole structure schematic diagram of the f-CaO digestion device for steel slag modification and particle size treatment according to the present application;

[0043] Figure 3 It is a physical diagram of the f-CaO digestion device for steel slag modification and particle size treatment according to the present application.

[0044] In the drawings: modifier pretreatment module 1, steel slag modification module 2, steel slag cooling and crushing module 3, steel slag fluidized bed screening digestion module 4, modifier storage bin 101, modifier crushing device 102, modifier preheating device 103, modifier conveying valve 104, first oscillator 105, slag channel 201, slag ladle 202, modification reactor 203, temperature control device 204, compressed air valve 205, air compressor 206, air lance 207, top cover 208, molten slag gas quenching and waste heat recovery device 301, first cyclone separator 302, waste heat boiler 303, roller crushing and waste heat recovery device 304, second oscillator 305, fluidized bed screening digestion reactor 401, second cyclone separator 402, fluidized bed carbonation digestion reactor 403, third cyclone separator 404, carbonation pressure device 405. DETAILED DESCRIPTION

[0045] The present application will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0046] The following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise defined, all technical terms used in the present application have the same meanings as generally understood by those skilled in the art. The terms used in the present application are only for the purpose of describing the specific embodiments and are not intended to limit the exemplary embodiments according to the present application.

[0047] Embodiment 1

[0048] A steel slag modification and particle size treatment f-CaO digestion device, as shown in Figure 1 , includes a modifier pretreatment module 1, a steel slag modification module 2, a steel slag cooling and crushing module 3, and a steel slag fluidized bed screening and digestion module 4. The modifier pretreatment module 1 is used for pretreatment of the modifier, and the pretreated modifier is sent to the steel slag modification module 2. The steel slag modification module 2 is used for modification of molten steel slag by pretreated modifier. The steel slag cooling and crushing module 3 is used for crushing and waste heat recovery of modified steel slag. The steel slag fluidized bed screening and digestion module 4 is used for steel slag screening, and different digestion methods are taken for steel slag of different particle sizes.

[0049] As shown in Figures 2-3 , the modifier pretreatment module 1 includes a modifier storage bin 101, a modifier crushing device 102, a modifier preheating device 103, a modifier conveying valve 104, and a first oscillator 105.

[0050] The steel slag modification module 2 includes a slag channel 201, a slag ladle 202, a modification reactor 203, a temperature control device 204, a compressed air valve 205, an air compressor 206, an air lance 207, and a top cover 208.

[0051] The steel slag cooling and crushing module 3 includes a molten slag gas quenching and waste heat recovery device 301, a first cyclone separator 302, a waste heat boiler 303, a roll crushing and waste heat recovery device 304, and a second oscillator 305.

[0052] The steel slag fluidized bed screening and digestion module 4 includes a fluidized bed screening and digestion reactor 401, a second cyclone separator 402, a fluidized bed carbonation digestion reactor 403, a third cyclone separator 404, and a carbonation pressure relief device 405.

[0053] Specifically, the modifier storage bin 101 is arranged above the modifier crushing device 102, the discharge port of the modifier storage bin 101 is connected with the feeding port of the modifier crushing device 102, the modifier is sent into the modifier crushing device 102 by gravity for crushing, the modifier preheating device 103 is arranged below the modifier crushing device 102, the discharge port of the modifier crushing device 102 is connected with the feeding port of the modifier preheating device 103, a plurality of first oscillators 105 are uniformly arranged on the side wall of the modifier preheating device 103, the discharge pipeline of the modifier preheating device 103 is arranged above the modification reactor 203, the modifier conveying valve 104 is arranged on the discharge pipeline of the modifier preheating device 103, the discharge pipeline of the modifier preheating device 103 is also connected with the second gas outlet of the first cyclone separator 302 through a pipeline, the compressed air valve 205 and the air compressor 206 are sequentially arranged between the second gas outlet of the first cyclone separator 302 and the discharge pipeline of the modifier preheating device 103, the gas outlet of the modifier preheating device 103 is connected with the first gas inlet of the waste heat boiler 303 through a pipeline, and the gas inlet of the modifier preheating device 103 is connected with the first gas outlet of the first cyclone separator 302 through a pipeline;

[0054] The slag groove 201 is a high-temperature-resistant groove, the slag groove 201 is arranged obliquely on the top of the slag ladle 202, the top of the slag groove 201 is connected with the molten steel slag outlet, the bottom of the slag groove 201 is fixedly connected with the slag ladle 202, the molten steel slag flows into the slag ladle 202 through the slag groove 201, the discharge port of the slag ladle 202 is arranged above the modification reactor 203, the top cover 208 is arranged above the modification reactor 203, the top cover 208 is an automatic concave cover, the middle part of the top cover 208 can be controlled to open and close, the discharge pipeline of the slag ladle 202 and the discharge pipeline of the modifier preheating device 103 are both arranged above the middle part of the top cover 208, a plurality of air lances 207 are uniformly arranged above the modification reactor 203, the temperature measuring end of the temperature control device 204 is arranged in the modification reactor 203, the temperature control device 204 is electrically connected with the modifier conveying valve 104, the modifier conveying valve 104 is also electrically connected with the compressed air valve 205, and the temperature control device 204 is used for monitoring the temperature in the modification reactor 203 and controlling the flow of the modifier conveying valve 104 and the compressed air valve 205;

[0055] The slag gas quenching and waste heat recovery device 301 is provided with a gas inlet for passing in low-temperature air. The feed inlet of the slag gas quenching and waste heat recovery device 301 is connected with the discharge outlet of the modification reactor 203, so that the modified slag is sent into the slag gas quenching and waste heat recovery device 301 for gas quenching. The gas outlet of the slag gas quenching and waste heat recovery device 301 is connected with the gas inlet of the first cyclone separator 302. The third gas outlet of the first cyclone separator 302 is connected with the second gas inlet of the waste heat boiler 303. The discharge outlet of the first cyclone separator 302 is connected with the first feed inlet of the fluidized bed carbonation digestion reactor 403, so that the mixed gas of high-temperature air and micro slag in the slag gas quenching and waste heat recovery device 301 enters the first cyclone separator for separation. The separated micro slag enters the fluidized bed carbonation digestion reactor 403, and the separated high-temperature air enters the waste heat boiler 303. The waste heat boiler 303 is provided with a water inlet and two outlets. The discharge outlet of the slag gas quenching and waste heat recovery device 301 is connected with the feed inlet of the roller crushing and waste heat recovery device 304, so that the gas-quenched slag enters the roller crushing and waste heat recovery device 304. The outer wall of the roller crushing and waste heat recovery device 304 is uniformly provided with a plurality of second oscillators 305. The top of the roller crushing and waste heat recovery device 304 is provided with a water inlet. The water vapor outlet of the roller crushing and waste heat recovery device 304 is connected with the first gas inlet of the fluidized bed carbonation digestion reactor 403. The second gas outlet of the roller crushing and waste heat recovery device 304 is connected with the second gas inlet of the fluidized bed screening digestion reactor 401. The water vapor in the roller crushing and waste heat recovery device 304 enters the fluidized bed carbonation digestion reactor 403 through the water vapor outlet of the roller crushing and waste heat recovery device 304 and the first gas inlet of the fluidized bed carbonation digestion reactor 403. The water vapor in the roller crushing and waste heat recovery device 304 enters the fluidized bed screening digestion reactor 401 through the second gas outlet of the roller crushing and waste heat recovery device 304 and the second gas inlet of the fluidized bed screening digestion reactor 401. The discharge outlet of the roller crushing and waste heat recovery device 304 is connected with the feed inlet of the fluidized bed screening digestion reactor 401.

[0056] The bottom of the fluidized bed screening digestion reactor 401 is provided with a first gas inlet, the first gas inlet of the fluidized bed screening digestion reactor 401 is used for introducing the steel plant flue gas / enriched CO2, the top of the fluidized bed screening digestion reactor 401 is provided with a first discharge port, the bottom of the fluidized bed screening digestion reactor 401 is provided with a second discharge port, the first discharge port of the fluidized bed screening digestion reactor 401 is connected with the feed inlet of the second cyclone separator 402, the discharge port of the second cyclone separator 402 is connected with the second feed inlet of the fluidized bed carbonation digestion reactor 403, the gas outlet of the second cyclone separator 402 is connected with the second gas inlet of the fluidized bed carbonation digestion reactor 403, the discharge port of the fluidized bed carbonation digestion reactor 403 discharges the micro-slag digestion product to complete the digestion, the gas outlet of the fluidized bed carbonation digestion reactor 403 is connected with the gas inlet of the third cyclone separator 404, and the discharge port of the third cyclone separator 404 also discharges the micro-slag digestion product;

[0057] The first gas outlet of the third cyclone separator 404 is connected with the third gas inlet of the fluidized bed carbonation digestion reactor 403, and the flue gas, carbon dioxide and / or water vapor in the third cyclone separator 404 are introduced into the fluidized bed carbonation digestion reactor 403 for reuse;

[0058] The second gas outlet of the third cyclone separator 404 is connected with the first gas inlet of the carbonation pressure suppression device 405, and the flue gas, carbon dioxide and / or water vapor in the third cyclone separator 404 are introduced into the carbonation pressure suppression device 405 for reaction;

[0059] The carbonation pressure suppression device 405 is provided with a water inlet for introducing normal temperature water;

[0060] The second discharge port of the fluidized bed screening digestion reactor 401 is connected with the feed inlet of the carbonation pressure suppression device 405, and the discharge port of the carbonation pressure suppression device 405 discharges the aggregate digestion product.

[0061] Specifically, the modifier is a silicon-rich industrial waste solid, which is used to treat waste with waste and saves cost;

[0062] Specifically, crushing the modifier can increase the contact area of the modifier and the steel slag and fully react;

[0063] Specifically, the slag groove 201 is a high-temperature-resistant heat preservation groove, and the slag ladle 202 is a high-temperature-resistant heat preservation box body, so that the normal flow of the liquid steel slag is maintained;

[0064] Specifically, the height of the slag ladle 202 is higher than the height of the modification reactor 203, and the gravity is used to make the molten steel slag drop into the modification reactor 203 through the discharge pipeline;

[0065] Specifically, the high-temperature air discharged through the first air outlet of the first cyclone separator 302 is used to preheat the modifier in the modifier preheating device 103, thereby improving the subsequent reaction efficiency. The high-temperature air in the second air outlet of the first cyclone separator 302 flows into the discharge pipeline of the modifier preheating device 103 through the compressed air valve 205 and the air compressor 206, so that the modifier is more quickly transported into the modification reactor 203.

[0066] Specifically, the waste heat boiler 303 recovers the high-temperature air in the modifier preheating device 103 and the slag gas quenching device 301 through the first air inlet and the second air inlet, and the normal-temperature water is introduced through the water inlet. The high-temperature air heats the normal-temperature water, and the hot water / water vapor and low-temperature air are discharged from the two discharge ports, thereby realizing waste heat recovery and improving energy utilization.

[0067] Specifically, the low-temperature air is normal-temperature-50°C, and the temperature of the low-temperature air can be adjusted according to the actual situation.

[0068] Specifically, the first air inlet and the second air inlet are arranged at the bottom of the fluidized bed screening digestion reactor 401, and the gas introduced is used to blow up the micro-slag in the fluidized bed screening digestion reactor 401. The micro-slag is blown up from the first discharge port at the top of the fluidized bed screening digestion reactor 401, enters the fluidized bed carbonation digestion reactor 403 through the second cyclone separator 402, and reacts in the fluidized bed carbonation digestion reactor 403.

[0069] The large-diameter steel slag is not blown up, and the second discharge port arranged at the bottom of the fluidized bed screening digestion reactor 401 enters the carbonation pressure suppression device 405 to realize screening treatment of the steel slag. The flow of the first air inlet and the second air inlet of the fluidized bed screening digestion reactor 401 can be controlled to control the screening of the particle size of the steel slag.

[0070] Specifically, the micro-slag and the enriched CO2 are introduced into the fluidized bed carbonation digestion reactor 403 from different positions through the second cyclone separator 402 to realize countercurrent contact, thereby enhancing the heat transfer and mass transfer effects.

[0071] Specifically, the particle size of the micro-slag is ≤2 mm, and the particle size of the large-diameter steel slag is >2 mm.

[0072] Specifically, the switch of the modifier crushing device 102 is controlled according to the particle size of the modifier. When the particle size of the modifier raw material is ≤0.075 mm, the modifier crushing device 102 is not started. If the particle size of the modifier raw material is >0.075 mm, the modifier crushing device 102 is started, and the particle size of the modifier is crushed to ≤0.075 mm, and then the air is transported to the modifier preheating device 103.

[0073] Specifically, when the system in the embodiment is used for the first time, the preheated modifier is introduced for reaction, and the normal-temperature modifier can be introduced through internal heat circulation for subsequent reactions.

[0074] Specifically, the second discharge port of the fluidized bed screening digestion reactor 401 can be connected to the feed ports of the plurality of carbonation pressure devices 405. When one carbonation pressure device 405 is working, the remaining carbonation pressure devices 405 can be used for digestion without waiting, and continuous operation can be achieved.

[0075] Example 2

[0076] A steel slag modification and particle size treatment f-CaO digestion method based on the steel slag modification and particle size treatment f-CaO digestion device in Example 1, including the following steps:

[0077] The modifier pretreatment module 1 is used for pretreatment and delivery of the modifier, and the pretreatment includes modifier crushing and modifier preheating;

[0078] The steel slag modification module 2 is used for heat preservation and storage of molten steel slag, and makes the molten steel slag react with the modifier;

[0079] The steel slag cooling and crushing module 3 is used for crushing and waste heat recovery of the modified molten steel slag;

[0080] The steel slag fluidized bed screening digestion module 4 is used for particle size screening of the crushed steel slag, and the steel slag is divided into large particle size steel slag and micro slag, and the large particle size steel slag and the micro slag are respectively subjected to digestion;

[0081] Specifically, the modifier in the modifier storage bin 101 is crushed by the modifier crushing device 102 according to the demand, the high-temperature air of about 800 DEG C generated in the slag gas quenching and waste heat recovery device is introduced into the modifier preheating device 103 through the first cyclone separator 302 to heat the modifier to about 300 DEG C, the high-temperature air in the modifier preheating device 103 is reduced to about 400 DEG C and then introduced into the waste heat boiler 303 for waste heat recovery, and the oscillator 105 arranged on the outer wall of the modifier preheating device 103 is used to prevent the internal modifier from being blocked and thus unable to move; at the same time, the high-temperature liquid slag of about 1650 DEG C is introduced into the slag ladle 202 through the slag channel 201 for storage, the slag channel 201 and the slag ladle 202 both have heat preservation measures to maintain the normal flow of the liquid slag, the high-temperature air of about 800 DEG C generated in the slag gas quenching and waste heat recovery device is introduced into the modifier preheating device 103 through the first cyclone separator 302, the flow is controlled by the compressed air valve 205, and the air is compressed by the air compressor 206, after the top cover 208 is completely opened, the compressed high-temperature air is used to transport the modifier into the modification reactor 203, the slag ladle 202 introduces the molten slag into the modification reactor 203, the molten slag and the modifier enter the modification reactor 203 at the same time, the modifier is sprayed into the flowing liquid slag by the air lance, the two are uniformly mixed, and then the reaction is carried out to obtain liquid slag of about 1400 DEG C; then low-temperature air is introduced into the slag gas quenching and waste heat recovery device 301 to crush the liquid slag of about 1400 DEG C, the low-temperature air is heated into high-temperature air of about 800 DEG C, the high-temperature air is separated from the slag dust by the first cyclone separator 302, the slag dust enters the fluidized bed carbonation digestion reactor 403 for digestion, the high-temperature air of about 800 DEG C is partially introduced into the modifier preheating device 103 to preheat the modifier, part of the high-temperature air is used to transport the modifier and control the temperature of the modification reactor 203, the temperature control device 204 detects the mixed temperature of the slag and the modifier in the modification reactor 203, changes the opening of the modifier conveying valve 104 and the compressed air valve 205 to control the temperature of the high-temperature modification reaction, and the remaining high-temperature air is directly introduced into the waste heat boiler 303 for waste heat recovery, the slag of about 900 DEG C discharged from the slag gas quenching device 301 enters the roller crushing and waste heat recovery device 304, and normal temperature water is introduced into the roller crushing and waste heat recovery device 304 to recover the heat of the slag, produce water vapor of about 600 DEG C, enter the fluidized bed screening digestion reactor 401 and the fluidized bed carbonation digestion reactor 403, and the oscillator 305 is arranged on the side wall of the roller crushing and waste heat recovery device 304 to prevent the slag from being blocked and thus unable to move during crushing and falling.The steel slag at about 700℃ discharged from the roller crushing and waste heat recovery device 304 enters the fluidized bed screening digestion reactor 401, and the steel slag is screened and the f-CaO in the steel slag is digested at the same time by using the steel plant flue gas / enriched CO2 and the water vapor at about 600℃ generated by the roller crushing and waste heat recovery device 304 as the blowing reaction gas. The fluidized bed screening digestion reactor 401 blows out the steel slag with a particle size of ≤2mm from the top by screening and digestion gas, and the steel slag with a particle size of >2mm is discharged from the bottom. The gas and dust mixture at about 500℃ is separated by the second cyclone separator 402. The steel slag with a particle size of ≤2mm and the steel slag powder from the first cyclone separator 302 all enter the fluidized bed carbonation digestion reactor 403. The gas separated by the second cyclone separator 402 is introduced from the bottom of the fluidized bed carbonation digestion reactor 403, and the water vapor at about 600℃ generated by the roller crushing and waste heat recovery device 304 is introduced as digestion gas. After a certain period of time, the micro-slag digestion product at about 100℃ is discharged from the bottom of the fluidized bed carbonation digestion reactor 403, and the gas-solid mixture at the top is separated by the third cyclone separator 404 to form a gas mixture and a micro-slag digestion product. The gas mixture is divided into two parts and introduced into the fluidized bed carbonation digestion reactor 403 and the carbonation pressure suppression device 405 as digestion gas for recycling. The steel slag with a particle size of >2mm at about 400℃ discharged from the fluidized bed screening digestion reactor 401 enters the carbonation pressure suppression device 405, and the normal temperature water is sprayed at the top of the carbonation pressure suppression device to heat the normal temperature water to generate water vapor, and a high pressure of 0.1-6MPa is formed in the carbonation pressure suppression device 405 to digest the large particle size steel slag with a particle size of >2mm. Multiple carbonation pressure suppression devices 405 are arranged to match the continuous operation of the fluidized bed screening digestion reactor 401 to realize the continuous digestion of the steel slag with a particle size of >2mm. After a period of time, the digested steel slag at about 50℃ is discharged as an aggregate digestion product.

[0082] Specifically, the temperature control device 204 detects the mixing temperature of the steel slag and the modifier in the modification reactor 203, and changes the opening degree of the modifier delivery valve 104 and the compressed air valve 205 to realize temperature control of the high-temperature modification reaction of the steel slag. After the appropriate amount of modifier is added, if the temperature in the modification reactor 203 is lower than 1600℃, the modifier delivery valve 104 is closed, and the opening degree of the compressed air valve 205 is appropriately increased to introduce more high-temperature air. Heat is released by the oxidation reaction of oxygen in the high-temperature air and low-valence iron in the steel slag to maintain the temperature in the modification reactor 203 at about 1600℃.

[0083] Specifically, the top cover 208 is arranged above the modification reactor 203, after the modifier is sprayed into the flowing steel slag through the air lance 207, the top cover 208 is closed, which has the heat preservation effect, at the same time, prevents the sprayed modifier from accumulating in the space above the modification reactor 203 in a large amount, improves the utilization rate of the modifier, and strengthens the mixing of the modifier and the steel slag.

[0084] Specifically, in the fluidized bed screening digestion reactor 401, the fluidized bed carbonation digestion reactor 403 and the carbonation pressure suppression device 405, water vapor and CO2-containing gas are used as reaction media to react with f-CaO in the steel slag to generate Ca(OH)2 and CaCO3 respectively, and Ca(OH)2 can also react with CO2 to generate CaCO3, so as to realize the digestion of f-CaO in the steel slag. Since the content of f-CaO in the steel slag decreases with the increase of the particle size of the steel slag, different process routes are adopted to treat steel slag of different particle sizes. After the steel slag is screened and preliminarily digested to 2mm in the fluidized bed screening digestion reactor 401, the steel slag with a particle size of ≤2mm is digested again by using water vapor and CO2-containing gas as reactants in the fluidized bed carbonation digestion reactor 403 due to the good heat transfer and mass transfer effect of the fluidized bed; and for the steel slag with a particle size of >2mm, since the content of f-CaO is low, the carbonation pressure suppression device 405 is used for digestion treatment.

[0085] Specifically, high-temperature air in different temperature ranges is introduced into different positions in the waste heat boiler 303 to generate water vapor or high-temperature water for users.

[0086] It is to be understood by those skilled in the art that the present application can be implemented by other embodiments without departing from the spirit or essential characteristics thereof. Therefore, the above disclosed embodiments are merely illustrative in all aspects and are not the only ones. All changes within the scope of the present application or within the scope equivalent to the present application are included in the present application.

[0087] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, any modification or equivalent replacement without departing from the spirit and scope of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A steel slag modification and size classification treatment f-CaO digestion device, characterized in that, The application relates to a steel slag modification device, which comprises a modifier pretreatment module (1), a steel slag modification module (2), a steel slag cooling and crushing module (3) and a steel slag fluidized bed screening and digestion module (4). The modifier pretreatment module (1) comprises a modifier storage bin (101), a modifier crushing device (102) and a modifier preheating device (103). The steel slag modification module (2) comprises a slag channel (201), a slag ladle (202) and a modification reactor (203). The steel slag cooling and crushing module (3) comprises a molten slag gas quenching and waste heat recovery device (301) and a roller pressing and crushing and waste heat recovery device (304). The steel slag fluidized bed screening and digestion module (4) comprises a fluidized bed screening and digestion reactor (401), a second cyclone separator (402), a fluidized bed carbonation digestion reactor (403) and a carbonation pressure suppression device (405). The discharge port of the modifier storage bin (101) is connected with the feeding port of the modifier crushing device (102), the discharge port of the modifier crushing device (102) is connected with the feeding port of the modifier preheating device (103), and the discharge pipeline of the modifier preheating device (103) is arranged above the feeding port of the modification reactor (203). The slag channel (201) is arranged above the slag ladle (202) in an inclined mode, the slag channel (201) is used for guiding molten steel slag into the slag ladle (202) for storage, the discharge port of the slag ladle (202) is arranged above the feeding port of the modification reactor (203), and the discharge port of the modification reactor (203) is connected with the feeding port of the molten slag gas quenching and waste heat recovery device (301). The molten slag gas quenching and waste heat recovery device (301) is provided with an air inlet for introducing low-temperature air, the discharge port of the molten slag gas quenching and waste heat recovery device (301) is connected with the feeding port of the roller pressing and crushing and waste heat recovery device (304), the roller pressing and crushing and waste heat recovery device (304) is provided with a water inlet for introducing normal-temperature water, the water vapor outlet of the roller pressing and crushing and waste heat recovery device (304) is connected with the first air inlet of the fluidized bed carbonation digestion reactor (403), the second air outlet of the roller pressing and crushing and waste heat recovery device (304) is connected with the second air inlet of the fluidized bed screening and digestion reactor (401), and the discharge port of the roller pressing and crushing and waste heat recovery device (304) is connected with the feeding port of the fluidized bed screening and digestion reactor (401). The bottom of the fluidized bed screening digestion reactor (401) is provided with a first gas inlet for introducing steel plant flue gas or enriched carbon dioxide, the top of the fluidized bed screening digestion reactor (401) is provided with a first discharge port, the first discharge port of the fluidized bed screening digestion reactor (401) is connected with the feed inlet of the second cyclone separator (402), the second discharge port of the fluidized bed screening digestion reactor (401) is connected with the feed inlet of the carbonation pressure plugging device (405), the discharge port of the carbonation pressure plugging device (405) discharges aggregate digestion products, the discharge port of the second cyclone separator (402) is connected with the second feed inlet of the fluidized bed carbonation digestion reactor (403), the gas outlet of the second cyclone separator (402) is connected with the second gas inlet of the fluidized bed carbonation digestion reactor (403), and the discharge port of the fluidized bed carbonation digestion reactor (403) discharges micro-slag digestion products. The steel slag cooling and crushing module (3) further comprises a first cyclone separator (302), the gas inlet of the first cyclone separator (302) is connected with the gas outlet of the molten slag gas quenching and waste heat recovery device (301), the first gas outlet of the first cyclone separator (302) is connected with the gas inlet of the modifier preheating device (103), the second gas outlet of the first cyclone separator (302) is connected with the discharge pipeline of the modifier preheating device (103), and the discharge port of the first cyclone separator (302) is connected with the first feed inlet of the fluidized bed carbonation digestion reactor (403); the steel slag cooling and crushing module (3) further comprises a waste heat boiler (303), the first gas inlet of the waste heat boiler (303) is connected with the gas outlet of the modifier preheating device (103), the second gas inlet of the waste heat boiler (303) is connected with the third gas outlet of the first cyclone separator (302), and the waste heat boiler (303) is further provided with a water inlet and an outlet.

2. The steel slag modification and size classification treatment f-CaO digestion device according to claim 1, characterized in that, The steel slag modification module (2) further comprises a temperature control device (204), a compressed air valve (205) and an air compressor (206); The discharge pipeline of the modifier preheating device (103) is provided with a modifier conveying valve (104); The first gas outlet of the first cyclone separator (302) and the gas inlet of the modifier preheating device (103) are sequentially provided with the compressed air valve (205) and the air compressor (206); The temperature measuring end of the temperature control device (204) is arranged in the modification reactor (203), the temperature control device (204) is electrically connected with the modifier conveying valve (104), the modifier conveying valve (104) is further electrically connected with the compressed air valve (205), and the temperature control device (204) is used for monitoring the temperature in the modification reactor (203) and controlling the flow of the modifier conveying valve (104) and the compressed air valve (205).

3. The steel slag modification and size classification treatment f-CaO digestion device according to claim 1, characterized in that, A plurality of first oscillators (105) are uniformly arranged on the outer wall of the modifier preheating device (103), and a plurality of second oscillators (305) are uniformly arranged on the outer wall of the roller crushing and waste heat recovery device (304).

4. The steel slag modification and size classification treatment f-CaO digestion device according to claim 1, characterized in that, The second discharge port of the fluidized bed screening digestion reactor (401) is connected with the feed ports of the carbonation pressure devices (405).

5. The steel slag modification and size classification treatment f-CaO digestion device according to claim 1, characterized in that, The steel slag fluidized bed screening digestion module (4) further comprises a third cyclone separator (404), the gas inlet of the third cyclone separator (404) is connected with the gas outlet of the fluidized bed carbonation digestion reactor (403), the first gas outlet of the third cyclone separator (404) is connected with the third gas inlet of the fluidized bed carbonation digestion reactor (403), and the second gas outlet of the third cyclone separator (404) is connected with the first gas inlet of the carbonation pressure device (405).

6. The steel slag modification and size classification treatment f-CaO digestion device according to claim 1, characterized in that, The modified reactor (203) is provided with a top cover (208) above, and a plurality of air lances (207) are uniformly arranged above the modified reactor (203).

7. A f-CaO digestion method for modifying and processing steel slag by particle size using the f-CaO digestion device of claim 1, characterized by, The method comprises the following steps: pretreating the modifier; carrying out a modification reaction on the pretreated modifier and the molten steel slag; crushing the molten steel slag after the modification reaction to obtain crushed steel slag; screening the crushed steel slag according to particle size into large-particle-size steel slag and micro slag, and taking different ways to digest the large-particle-size steel slag and the micro slag respectively.

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