Method and system for nitrogen removal of secondary aluminum ash by utilizing steel slag heat braising sensible heat synergistic treatment

Abstract

The invention provides a method and a system for co-processing secondary aluminum ash for denitrification by using steel slag heat stewing sensible heat, and relates to the field of metallurgical solid waste resource utilization. The method comprises the following steps: pouring high-temperature steel slag into a hot braising pool, and covering with cooling water for hot braising; the hot stewing tank is communicated with a steam air draft pipeline and an ammonia air draft pipeline; pouring the secondary aluminum ash into a hot braising pool, and carrying out high-temperature hydrolysis denitrification on the secondary aluminum ash by utilizing water absorbing the waste heat of the steel slag; continuously injecting water into the hot braising pool for hot braising and denitrification reaction, and opening a hot braising cover until the steel slag is cooled to room temperature; separating steel slag and secondary aluminum ash slurry, carrying out hydraulic filtration on the secondary aluminum ash slurry, drying the secondary aluminum ash slurry by adopting steam generated by hot braising, mixing the dried secondary aluminum ash slurry with active lime, and briquetting to prepare a steelmaking auxiliary material slagging agent; the filtrate is used as a raw material for preparing denitration slurry. According to the method, the hot water absorbing the waste heat of the steel slag is used for secondary aluminum ash denitrification, and products of secondary aluminum ash denitrification can be recycled, so that resource utilization of metallurgical solid waste is fully realized.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of metallurgical solid wastes, and particularly relates to a method and a system for synergistically treating denitrification of secondary aluminum ash by using the sensible heat of hot stewing of steel slag. Background Art

[0002] Secondary aluminum ash is a solid waste obtained by extracting aluminum from aluminum melting slag. Since secondary aluminum ash contains substances such as aluminum oxide, aluminum nitride, and metallic aluminum, it has a high recycling value; however, aluminum nitride in secondary aluminum ash is extremely easy to react with water to generate toxic and malodorous gases such as ammonia gas, and it belongs to hazardous waste.

[0003] Steel slag is a by-product generated during the steelmaking process, and the production amount is about 10% of crude steel. At present, the recycling of steel slag mainly recovers valuable elements therein through crushing, screening, and magnetic separation. The steel slag magnetic separation powder obtained by magnetic separation is used in the sintering or steelmaking process, and the tail slag after magnetic separation is used as a cement admixture or roadbed material; before the recycling of steel slag, it needs to be pretreated by a hot stewing process to cool the hot steel slag from more than one thousand degrees to room temperature, and at the same time, the steel slag is crushed. However, the heat during the hot stewing and cooling of steel slag cannot be recycled and utilized at present.

[0004] In the prior art, such as the patent application CN118321322A discloses a method for removing aluminum nitride in secondary aluminum ash, in which secondary aluminum ash, a catalyst, and a retarder are mixed and added with water to form a reaction slurry, and aluminum nitride in the secondary aluminum ash is hydrolyzed by stirring to achieve efficient removal of aluminum nitride in the secondary aluminum ash; in addition, the paper "Research on the Removal of Aluminum Nitride in Secondary Aluminum Ash by Hydrolysis and Its Mechanism" published in the journal "Hydrometallurgy" proposes adding secondary aluminum ash to a calcium oxide - glucose hydrolysis system to remove aluminum nitride. Although the above methods for treating secondary aluminum ash can remove aluminum nitride therein, they all need to add a catalyst, and the cost is relatively high, which is not suitable for popularization and use. Therefore, seeking a low-cost and highly applicable method to treat secondary aluminum ash is of great significance for the resource utilization of metallurgical solid wastes. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and a system for synergistically treating denitrification of secondary aluminum ash by using the sensible heat of hot stewing of steel slag, fully utilizing the waste heat of steel slag to heat cooling water to treat secondary aluminum ash denitrification, making the generated ammonia gas into ammonia water and then using it as a raw material for preparing denitrification slurry, and returning the denitrified secondary aluminum ash as a high-aluminum raw material to the steelmaking process as a slag melting agent, thus putting forward a new idea for the combined utilization of the waste heat of steel slag and secondary aluminum ash.

[0006] To achieve the above purpose, the present invention proposes the following technical solutions:

[0007] In the first aspect, a method for synergistically treating denitrification of secondary aluminum ash by using the sensible heat of hot stewing of steel slag is proposed, including the following steps:

[0008] 1) Pour the high-temperature steel slag evenly into the hot stewing pool, cover it with cooling water for hot stewing, open the steam exhaust pipe and close the ammonia exhaust pipe; wherein, the steam exhaust pipe and the ammonia exhaust pipe are arranged on the hot stewing tank and communicated to the hot stewing pool;

[0009] 2) Pour the secondary aluminum ash evenly into the hot stewing pool, open the ammonia exhaust pipe and close the steam exhaust pipe, and use the hot water after the heat exchange between the hot stewing pool and the steel slag to carry out high-temperature hydrolysis denitrification on the secondary aluminum ash, so that AlN in the secondary aluminum ash is hydrolyzed to form Al(OH)3 and NH3;

[0010] 3) Continuously inject water into the hot stewing pool for hot stewing and denitrification reaction until the hot stewing and denitrification are completed and the temperature of the steel slag cools to room temperature, then open the hot stewing cover;

[0011] 4) After hot stewing, separate the steel slag and the secondary aluminum ash slurry. The steel slag is cleaned and transported to the steel slag treatment workshop. The secondary aluminum ash slurry is filtered and dried with the steam generated during the hot stewing process and then mixed and pressed with active lime to make a slag melting agent for steelmaking auxiliary materials; the filtrate of the secondary aluminum ash slurry is used as the raw material for preparing the denitrification slurry.

[0012] Further, in step 1), the temperature of the steel slag is higher than 800 °C, and the mass of the cooling water added to the hot stewing pool for hot stewing is 30-50% of the mass of the steel slag.

[0013] Further, in step 2), the secondary aluminum ash is added when the temperature of the steel slag in the hot stewing pool is lower than 200 °C, and the added mass of the secondary aluminum ash is 10-20% of the mass of the steel slag.

[0014] Further, it also includes:

[0015] The NH3 extracted by the ammonia exhaust pipe is introduced into the water pool to form an ammonia aqueous solution and is transported to the denitrification process to prepare the denitrification slurry; wherein, the mass of the water contained in the water pool is 1-1.3 times the mass of the secondary aluminum ash.

[0016] Further, in step 3), the water injection volume for continuously injecting water into the hot stewing pool for hot stewing and denitrification reaction is 5-10% of the sum of the masses of the steel slag and the secondary aluminum ash.

[0017] Further, the content of AlN in the secondary aluminum ash is higher than 10%.

[0018] Further, the time for hot stewing with cooling water covering in step 1) is 15-30 min.

[0019] Further, the time for injecting water into the hot stewing pool for hot stewing and denitrification reaction in step 3) is 10-20 min.

[0020] Further, in step 4), the secondary aluminum ash slurry is subjected to hydraulic filtration and then dried with the steam generated during the heat insulation process to obtain aluminum-containing dry material, and the water content of the aluminum-containing dry material does not exceed 1%; the aluminum-containing dry material and active lime are mixed and briquetted according to a mass ratio of 1:0.8 - 1.6 to obtain a slag melting agent.

[0021] In a second aspect, a system for synergistically treating secondary aluminum ash denitrification by utilizing the sensible heat of hot steel slag is proposed, including:

[0022] A heat insulation pool for accommodating hot steel slag with a temperature not lower than 800°C and hot water insulation, and further accommodating secondary aluminum ash for denitrification reaction after the temperature of the steel slag drops to 200°C, until the heat insulation and denitrification are completed and the temperature of the steel slag cools to room temperature and then it is removed from the heat insulation pool;

[0023] A first transportation unit for transporting high-temperature steel slag to the heat insulation pool;

[0024] A second transportation unit for transporting secondary aluminum ash to the heat insulation pool;

[0025] A water supply unit for supplying water to the heat insulation pool and the ammonia water pool;

[0026] A separation unit for separating the steel slag and secondary aluminum ash slurry cooled to room temperature;

[0027] A cleaning and transportation unit for cleaning the steel slag cooled to room temperature and transporting it to the steel slag treatment workshop;

[0028] A pressure filtration separation unit for pressure filtering the secondary aluminum ash slurry to separate the filter cake and the filtrate;

[0029] A drying unit, the drying unit uses steam for drying, the input end of the drying unit is connected to the heat insulation pool to collect the steam generated by the high-temperature heat insulation of the steel slag, and is used for drying the filter cake separated by the pressure filtration separation unit to obtain aluminum-containing dry material;

[0030] A third transportation unit for collecting the filtrate and transporting it to the denitrification process as a raw material for preparing the denitrification slurry;

[0031] An ammonia production unit, including an ammonia water pool and an ammonia gas extraction pipeline, the input end of the ammonia gas extraction pipeline is connected to the heat insulation pool to collect the NH3 generated by the high-temperature hydrolysis denitrification of secondary aluminum ash, and the output end of the ammonia gas extraction pipeline is connected to the ammonia water pool, and is used for introducing NH3 into the water in the ammonia water pool to form an ammonia water solution and then transporting it to the denitrification process to prepare the denitrification slurry.

[0032] From the above technical solutions, it can be seen that the technical solutions of the present invention have obtained the following beneficial effects:

[0033] The invention discloses a method and system for utilizing sensible heat of hot stewing of steel slag to collaboratively treat secondary aluminum ash for denitrification. The method comprises: evenly pouring high-temperature steel slag into a hot stewing pool, and hot stewing with a cover using cooling water; wherein a steam exhaust duct and an ammonia exhaust duct connected to the hot stewing pool are provided on the hot stewing tank; evenly pouring secondary aluminum ash into the hot stewing pool, and performing high-temperature hydrolysis and denitrification on the secondary aluminum ash using hot water obtained after heat exchange between the hot stewing pool and the steel slag; continuously injecting water into the hot stewing pool for hot stewing and denitrification reaction, and opening the hot stewing cover after the temperature of the steel slag is cooled to room temperature; separating steel slag and secondary aluminum ash slurry, and transporting the steel slag to a steel slag treatment workshop after cleaning, and hydraulically filtering the secondary aluminum ash slurry and drying it with steam generated during the hot stewing process, and then mixing it with active lime and pressing it into blocks to prepare a slag-removing agent for steelmaking auxiliary materials; and using the filtrate as cooling water for hot stewing of high-temperature steel slag. On the one hand, the present invention uses hot water generated by hot stewing of steel slag to treat secondary aluminum ash, fully utilizing the waste heat of high-temperature steel slag and recovering the heat of steel slag; on the other hand, the solid phase in the secondary aluminum ash slurry after denitrification is dried by high-temperature steam generated by hot stewing of high-temperature steel slag and can continue to be used as a high-aluminum raw material and mixed with active lime to prepare steelmaking auxiliary materials. At the same time, the ammonia gas generated by the denitrification reaction is made into ammonia water and the filtrate separated from the secondary aluminum ash slurry is used to prepare sintering denitrification slurry.

[0034] Based on the basic characteristics of AlN in secondary aluminum ash and the characteristic that the sensible heat of hot stewing of steel slag cannot be recovered, the present invention utilizes the characteristic that hot water can improve the denitrification of secondary aluminum ash, hydrolyzes it and proposes a method for coordinating the denitrification of secondary aluminum ash by utilizing the sensible heat of hot stewing of steel slag; the denitrified secondary aluminum ash can be used as a steelmaking auxiliary material, and the valuable elements such as Al and Ca therein can be fully utilized; the generated ammonia can be captured to prepare denitrification slurry, and finally the recycling of various solid wastes can be realized, and the resource utilization of metallurgical solid waste and the recovery of valuable elements can be efficiently achieved.

[0035] It should be appreciated that all combinations of the foregoing concepts, as well as additional concepts described in greater detail below, may be considered to be part of the inventive subject matter of the present disclosure, provided such concepts are not mutually inconsistent.

[0036] The foregoing and other aspects, embodiments and features of the present invention can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as the features and / or beneficial effects of the exemplary embodiments, will be apparent from the following description or learned from the practice of the specific embodiments according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are not drawn to scale according to actual reference objects. In the accompanying drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For the sake of clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the present invention will be described by way of example and with reference to the accompanying drawings, in which:

[0038] Figure 1 This is the flow chart of the method for synergistically treating denitrification of secondary aluminum ash by utilizing the sensible heat of hot stewing of steel slag in the present invention;

[0039] Figure 2 This is the block diagram of the method for synergistically treating denitrification of secondary aluminum ash by utilizing the sensible heat of hot stewing of steel slag in the present invention;

[0040] Figure 3 This is the block diagram of the system for synergistically treating denitrification of secondary aluminum ash by utilizing the sensible heat of hot stewing of steel slag in the present invention. Specific embodiments

[0041] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains.

[0042] The "first", "second" and similar terms used in the specification and claims of this patent application of the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "a", "an" or "the" and similar terms do not denote a quantity limitation, but mean that there is at least one. The terms such as "comprising" or "including" are intended to indicate that the elements or objects appearing before "comprising" or "including" cover the features, wholes, steps, operations, elements and / or components listed after "comprising" or "including", and do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0043] Both steel slag and secondary aluminum ash are solid wastes generated in the current steelmaking process. Among them, steel slag is currently mainly recycled valuable elements through crushing or magnetic separation, and secondary aluminum ash mainly removes aluminum nitride components through catalysts, etc. The former does not recover the heat of steel slag, and the latter has a high cost, both of which result in waste of resources. Therefore, the present invention aims to propose a method and system for synergistically treating denitrification of secondary aluminum ash by utilizing the sensible heat of hot stewing of steel slag, to solve the problems of difficult recovery and utilization of the waste heat of steel slag and secondary aluminum ash, and directly apply the waste heat of steel slag to treat aluminum nitride in secondary aluminum ash, with low cost and suitable for popularization and use.

[0044] Specifically, in combination with Figure 1 and Figure 2As shown, the method disclosed in the present invention for co-processing secondary aluminum ash denitrification by using sensible heat from hot stewing of steel slag comprises the following steps:

[0045] Step S1, pour the high-temperature steel slag evenly into the hot stewing pool, cover the hot stewing with cooling water, open the steam exhaust pipe, and close the ammonia exhaust pipe; wherein, the steam exhaust pipe and the ammonia exhaust pipe are arranged on the hot stewing tank and connected to the hot stewing pool; in this step, the temperature of the steel slag is higher than 800°C, the mass of cooling water added to the hot stewing pool for hot stewing is 30-50% of the mass of the steel slag, and the time of hot stewing with cooling water covering is 15-30 minutes; the high-temperature steel slag undergoes heat exchange with the cooling water, which not only heats the cooling water, but also generates a large amount of steam, so at this stage, the steam exhaust pipe is opened to extract the hot steam and can be incorporated into the enterprise steam pipeline network;

[0046] Step S2, pouring the secondary aluminum ash evenly into the hot stewing pool, using the hot water after the hot stewing pool and the steel slag heat exchange to perform high-temperature hydrolysis and denitrification on the secondary aluminum ash, so that AlN in the secondary aluminum ash is hydrolyzed to form Al(OH)3 and NH3; wherein, the content of AlN in the secondary aluminum ash is higher than 10%, the timing of adding the secondary aluminum ash into the hot stewing pool is when the temperature of the steel slag is lower than 200°C, and the added mass of the secondary aluminum ash is 10-20% of the mass of the steel slag; after the secondary aluminum ash is added, the hot water reacts with it to generate NH3, so in this stage, the steam exhaust duct is closed and the ammonia exhaust duct is opened;

[0047] Step S3, continuously injecting water into the hot stewing pool for hot stewing and denitrification reaction until the hot stewing and denitrification are completed and the temperature of the steel slag is cooled to room temperature, and then opening the hot stewing cover; wherein the amount of water continuously injected into the hot stewing pool for hot stewing and denitrification reaction is 5-10% of the sum of the mass of the steel slag and the secondary aluminum ash, and the conventional time for injecting water into the hot stewing pool for hot stewing and denitrification reaction is 10-20 minutes;

[0048] Step S4, after hot stewing, the steel slag and the secondary aluminum ash slurry are separated, the steel slag is cleaned and transported to a steel slag processing workshop, the secondary aluminum ash slurry is hydraulically filtered and dried with the steam generated in the hot stewing process, and then mixed with active lime and pressed into blocks to prepare a slag-removing agent, an auxiliary material for steelmaking; the filtrate of the secondary aluminum ash slurry is used as a raw material for preparing denitrification slurry; wherein, the secondary aluminum ash slurry is hydraulically filtered and dried with the steam generated in the hot stewing process to obtain an aluminum-containing dry material, and the water content of the aluminum-containing dry material does not exceed 1%; the aluminum-containing dry material and active lime are mixed and pressed into blocks in a mass ratio of 1:0.8-1.6 to obtain a slag-removing agent.

[0049] The NH3 extracted from the ammonia exhaust pipe is introduced into a water pool to form an ammonia solution and transported to the denitration process to prepare a denitration slurry together with the filtrate; wherein the mass of water contained in the water pool is 1 to 1.3 times the mass of the secondary aluminum ash.

[0050] The method for co-treatment of secondary aluminum ash denitrification by utilizing sensible heat from hot stewing of steel slag disclosed in the present invention will be further specifically introduced below in conjunction with specific embodiments.

[0051] Example 1

[0052] The method of using slag hot stewing sensible heat to coordinately treat secondary aluminum ash denitrification has the following process flow:

[0053] Step 1: Send 10t of high-temperature slag above 800℃ to the slag treatment workshop and pour it evenly into the hot stewing pool. Add 4t of cooling water and stew for 25min. The generated steam is then merged into the steam network through the steam exhaust pipe.

[0054] Step 2: When the temperature of the steel slag is lower than 200°C, 1 t of secondary aluminum ash is added, and the generated NH3 is introduced into a 110 kg closed water tank through an ammonia exhaust pipe to prepare an ammonia solution;

[0055] Step 3: Slowly inject water into the hot stewing pool for 8 minutes, with a water injection volume of 1.1t, cover the hot stewing cover, and carry out hot stewing and denitrification hydrolysis for 15 minutes. When the slag temperature reaches room temperature and the reaction is completed, open the hot stewing cover;

[0056] Step 4: After hot stewing, separate the steel slag and secondary aluminum ash slurry, clean the steel slag after hot stewing until there is no obvious secondary aluminum ash slurry residue on the surface of the steel slag; at the same time, filter the secondary aluminum ash slurry, and dry it with the steam generated during the hot stewing process. The moisture content of the aluminum dry material is 0.8%. The aluminum dry material is mixed with active lime in a mass ratio of 1:1 to prepare briquettes to obtain a slag-removing agent; the filtrate separated from the secondary aluminum ash slurry is sent to the denitrification process as a raw material for preparing sintering denitrification slurry.

[0057] Another embodiment of the present invention provides a system for co-processing secondary aluminum ash denitrification by using sensible heat from hot stewing of steel slag. The system is used to implement the specific process of the method for co-processing secondary aluminum ash denitrification by using sensible heat from hot stewing of steel slag, and specifically includes the following structure;

[0058] The hot stewing pool is used to accommodate molten steel slag with a temperature not lower than 800°C and water for hot stewing, and after the temperature of the molten steel slag drops to 200°C, it further accommodates secondary aluminum ash for denitrification reaction until hot stewing and denitrification are completed, and the molten steel slag temperature cools to room temperature and then is removed from the hot stewing pool; the first transportation unit is used to transport high-temperature molten steel slag to the hot stewing pool; the second transportation unit is used to transport secondary aluminum ash to the hot stewing pool; the water supply unit is used to supply water to the hot stewing pool and the ammonia water tank; the separation unit is used to separate the molten steel slag and secondary aluminum ash slurry cooled to room temperature; the cleaning and transfer unit is used to clean the molten steel slag cooled to room temperature and transfer it to the molten steel slag treatment workshop; the pressure filtration and separation unit is used to perform pressure filtration on the secondary aluminum ash slurry to separate the filter cake and the filtrate; the drying unit, the drying unit uses steam drying, the input end of the drying unit is connected to the hot stewing pool to collect the steam generated by the hot stewing of high-temperature molten steel slag, and is used to dry the filter cake separated by the pressure filtration and separation unit to obtain aluminum-containing dry material; the third transportation unit is used to collect the filtrate and transport it to the denitrification process as a raw material for preparing denitrification slurry; the ammonia production unit includes an ammonia water tank and an ammonia gas extraction pipeline, the input end of the ammonia gas extraction pipeline is connected to the hot stewing pool to collect NH3 generated by the high-temperature hydrolysis and denitrification of secondary aluminum ash, and the output end of the ammonia gas extraction pipeline is connected to the ammonia water tank, and is used to introduce NH3 into the water in the ammonia water tank to form an ammonia water solution and then transport it to the denitrification process to prepare denitrification slurry with the filtrate.

[0059] In the prior art, secondary aluminum ash is directly used to prepare the slag melting agent calcium aluminate. However, using this calcium aluminate in steelmaking will increase the nitrogen content in the molten steel. For example, adding calcium aluminate directly made from 5% secondary aluminum ash in steelmaking as a slag melting agent will increase the nitrogen content in the molten steel by 10 ppm. While the slag melting agent prepared by this solution will not increase the nitrogen content when applied in steelmaking. The present invention makes full use of the un-recovered hot water generated during the hot stewing of molten steel slag, and utilizes the characteristic that hot water can improve the denitrification rate of secondary aluminum ash to perform hydrolysis and denitrification on secondary aluminum ash. The ammonia gas generated by denitrification is absorbed by water to form an ammonia water solution, which can be used to prepare denitrification slurry with the ash slurry filtrate after the hydrolysis of secondary aluminum ash. The treated secondary aluminum ash can be used as a high-aluminum raw material and mixed with active lime to prepare the slag melting agent used in steelmaking, ultimately achieving the goal of resource utilization and recovery of valuable elements.

[0060] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by what is defined in the claims.

Claims

1. A method for synergistically treating denitrification of secondary aluminum ash by utilizing the sensible heat of hot stewing of steel slag, characterized in that, It includes the following steps: 1) Pour the high-temperature steel slag evenly into the heat-insulating pool, cover it with cooling water for heat insulation, open the steam extraction pipeline, and close the ammonia extraction pipeline; wherein, the steam extraction pipeline and the ammonia extraction pipeline are arranged on the heat-insulating tank and communicated to the heat-insulating pool; 2) Pour the secondary aluminum ash evenly into the heat-insulating pool, open the ammonia extraction pipeline, close the steam extraction pipeline, and use the hot water after the heat exchange between the heat-insulating pool and the steel slag to carry out high-temperature hydrolysis denitrification on the secondary aluminum ash, so that AlN in the secondary aluminum ash is hydrolyzed to form Al(OH)3 and NH3; 3) Continuously inject water into the heat-insulating pool for heat insulation and denitrification reaction until the heat insulation and denitrification are completed and the temperature of the steel slag is cooled to room temperature, then open the heat-insulating cover; 4) After heat insulation, separate the steel slag and the secondary aluminum ash slurry. The steel slag is washed and transported to the steel slag treatment workshop. The secondary aluminum ash slurry is filter-pressed and dried with the steam generated during the heat-insulating process, and then mixed and briquetted with active lime to produce a slag melting agent for steelmaking; the filtrate of the secondary aluminum ash slurry is used as the raw material for preparing the denitrification slurry.

2. The method for synergistically treating secondary aluminum ash denitrification by utilizing the sensible heat of steel slag hot smothering according to claim 1, characterized in that In step 1), the temperature of the steel slag is higher than 800°C, and the mass of the cooling water added to the heat-insulating pool for heat insulation is 30-50% of the mass of the steel slag.

3. The method for synergistically treating denitrification of secondary aluminum ash by utilizing the sensible heat of hot stewing of steel slag according to claim 1, characterized in that In step 2), the secondary aluminum ash is added when the temperature of the steel slag in the heat-insulating pool is lower than 200°C, and the added mass of the secondary aluminum ash is 10-20% of the mass of the steel slag.

4. The method for synergistically treating secondary aluminum ash denitrification by utilizing the sensible heat of steel slag hot smothering according to claim 1, characterized in that, It also includes: The NH3 extracted by the ammonia extraction pipeline is introduced into the water pool to form an ammonia aqueous solution and is transported to the denitrification process to prepare the denitrification slurry; wherein, the mass of the water contained in the water pool is 1-1.3 times the mass of the secondary aluminum ash.

5. The method for denitrification of secondary aluminum ash by utilizing sensible heat from hot stewing of steel slag according to claim 1, characterized in that: In step 3), the water injection volume for continuously injecting water into the heat-insulating pool for heat insulation and denitrification reaction is 5-10% of the sum of the masses of the steel slag and the secondary aluminum ash.

6. The method for synergistically treating denitrification of secondary aluminum ash by utilizing the sensible heat of hot stewing of steel slag according to claim 1, characterized in that, The content of AlN in the secondary aluminum ash is higher than 10%.

7. The method for synergistically treating secondary aluminum ash denitrification by using the sensible heat of hot stewing of steel slag according to claim 1, characterized in that, In step 1), the time for heat insulation with cooling water covering is 15-30 min.

8. The method for synergistically treating secondary aluminum ash denitrification by utilizing the sensible heat of hot stewing of steel slag according to claim 1, characterized in that, In step 3), the time for injecting water into the heat-insulating pool for heat insulation and denitrification reaction is 10-20 min.

9. The method for synergistically treating secondary aluminum ash denitrification by utilizing the sensible heat of hot stewing of steel slag according to claim 1, characterized in that, In step 4), the secondary aluminum ash slurry is filter-pressed and dried with the steam generated during the heat-insulating process to obtain aluminum-containing dry material, and the water content of the aluminum-containing dry material does not exceed 1%; the aluminum-containing dry material and active lime are mixed and briquetted according to a mass ratio of 1:0.8-1.6 to produce a slag melting agent.

10. A system for synergistically treating denitrification of secondary aluminum ash by utilizing the sensible heat of hot stewing of steel slag, characterized in that, It includes: A heat-insulating pool for accommodating the heat insulation of the steel slag with a temperature not lower than 800°C and water, and further accommodating the secondary aluminum ash for denitrification reaction after the temperature of the steel slag is reduced to 200°C, and removing it from the heat-insulating pool until the heat insulation and denitrification are completed and the temperature of the steel slag is cooled to room temperature; The first transportation unit for transporting the high-temperature steel slag to the heat-insulating pool; The second transportation unit for transporting the secondary aluminum ash to the heat-insulating pool; The water supply unit for supplying water to the heat-insulating pool and the ammonia water pool; The separation unit for separating the steel slag and the secondary aluminum ash slurry cooled to room temperature; The cleaning and transportation unit for cleaning the steel slag cooled to room temperature and transporting it to the steel slag treatment workshop; The filter-pressing and separation unit for filter-pressing the secondary aluminum ash slurry to separate the filter cake and the filtrate; Drying unit, the drying unit uses steam drying, the input end of the drying unit is connected to the hot stewing pool to collect the steam generated by the hot stewing of high-temperature steel slag, which is used to dry the filter cake to obtain aluminum-containing dry material; The third transportation unit is used to collect the filtrate and transport it to the denitrification process as a raw material for preparing denitrification slurry; Ammonia production unit, including an ammonia water tank and an ammonia gas extraction pipeline. The input end of the ammonia gas extraction pipeline is connected to the hot stewing pool to collect NH3 generated by the high-temperature hydrolysis and denitrification of secondary aluminum ash. The output end of the ammonia gas extraction pipeline is connected to the ammonia water tank, which is used to introduce NH3 into the water in the ammonia water tank to form an ammonia water solution and then transport it to the denitrification process to prepare denitrification slurry with the filtrate.

Images