Method for comprehensively utilizing secondary aluminum ash solid waste

Abstract

A comprehensive utilization method of secondary aluminum ash solid waste comprises the following steps: preparing secondary aluminum ash and sodium hydroxide according to a proper ratio, adding a proper amount of water, and carrying out heating and stirring reaction to generate a gas product and solid slurry; carrying out a deamination reaction on the gas product through a deamination solution, and collecting gas obtained after the gas product is subjected to the deamination reaction; filtering the deamination solution after the deamination reaction to obtain a crude ammonium salt solution and a first crude aluminum hydroxide product, evaporating and crystallizing the crude ammonium salt solution to obtain crude ammonium salt, and collecting the first crude aluminum hydroxide product; carrying out secondary heating and stirring reaction on the solid slurry and sodium hydroxide in a proper proportion; filtering the reacted solid slurry to obtain filtrate and ash, and carrying out neutralization reaction on the filtrate and a neutralization solution in a certain proportion to obtain neutralized slurry; filtering and neutralizing the slurry to obtain a sodium fortune salt solution and a second crude aluminum hydroxide product, performing evaporative crystallization on the sodium fortune salt solution to obtain sodium fortune salt, and collecting the second crude aluminum hydroxide product; stirring and mixing sodium formate and ash according to a certain ratio; according to the technology, waste residues, waste water and waste gas can be recycled, the problem of'three wastes' pollution is solved, and meanwhile efficient utilization of secondary aluminum ash is achieved.

Description

Technical Field

[0001] This invention relates to the field of aluminum ash treatment technology, specifically a method for the comprehensive utilization of secondary aluminum ash solid waste. Background Technology

[0002] Domestic primary aluminum ash is valued and treated by enterprises as a resource due to its high aluminum content and economic value.

[0003] The potential value of aluminum ash mainly lies in the metallic aluminum, alumina, and thermal energy it contains. However, secondary aluminum ash, as a residue after aluminum extraction from primary aluminum ash, was abandoned or buried before the implementation of the environmental protection tax due to the lack of technologically mature, economically efficient, and cost-effective disposal projects in China. This not only wasted resources but also polluted the environment, which is extremely inconsistent with the current concept of green development.

[0004] From the perspectives of the properties, composition, and potential value of secondary aluminum ash, the key to the resource utilization of aluminum ash lies in secondary aluminum ash. Therefore, the times call for the rapid development and promotion of mature, economically efficient, and cost-effective disposal technologies. Based on my country's national conditions, examining the current problems in aluminum ash disposal and exploring how to utilize aluminum ash in a resource-based manner has become a problem that my country's aluminum industry is currently facing and addressing.

[0005] The characteristics of aluminum ash are mainly reflected in three aspects: (1) It is toxic and reactive, and is classified as hazardous waste; (2) It is produced in large quantities, with millions of tons discharged annually in my country; (3) It contains metallic aluminum, aluminum compounds and thermal energy, and has high potential value. Summary of the Invention

[0006] The present invention aims to solve the problems existing in the background technology and provides a method for comprehensive utilization of secondary aluminum ash solid waste, which at least solves some of the technical problems in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for comprehensive utilization of secondary aluminum ash solid waste includes the following steps:

[0009] Includes the following steps:

[0010] Prepare appropriate proportions of secondary aluminum ash and sodium hydroxide, add appropriate amount of water, heat and stir to react, and generate gaseous products and solid slurry;

[0011] The gaseous product is passed through a deammoniation solution to undergo a deammoniation reaction, and the gaseous product after the deammoniation reaction is collected. The deammoniation solution after the deammoniation reaction is filtered to obtain a crude ammonium salt solution and a first crude aluminum hydroxide. The crude ammonium salt solution is evaporated and crystallized to obtain crude ammonium salt, and the first crude aluminum hydroxide is collected.

[0012] The solid slurry is reacted with an appropriate amount of sodium hydroxide by secondary heating and stirring.

[0013] The reacted solid slurry is filtered to obtain filtrate and ash residue. The filtrate is then neutralized with a neutralizing liquid of a certain proportion to obtain neutralized slurry.

[0014] The slurry was filtered and neutralized to obtain sodium fluorocarbonate solution and second crude aluminum hydroxide. The sodium fluorocarbonate solution was evaporated and crystallized to obtain sodium fluorocarbonate, and the second crude aluminum hydroxide was collected.

[0015] Sodium thiocyanate and ash are mixed in a certain ratio.

[0016] In a further embodiment, the mass ratio of the secondary aluminum ash to sodium hydroxide is 1:(1-5), wherein the mass ratio of sodium hydroxide is 5-40%, the stirring temperature is 10-95℃, the stirring time is 10-720 min, and nitrogen or inert gas is purged online during the heating and stirring process.

[0017] In a further embodiment, the deammoniation solution is one of dilute sulfuric acid, dilute hydrochloric acid, dilute nitric acid, or aluminum sulfate.

[0018] In a further embodiment, the gas after the ammonia removal reaction is mixed with air in a certain proportion and then transported to a combustion power generation unit.

[0019] In a further embodiment, the mass ratio of the solid slurry to sodium hydroxide is 1:(1-5), wherein the mass ratio of sodium hydroxide is 5-40%, the stirring temperature is 10-95℃, the stirring time is 10-720 min, and nitrogen or inert gas is purged online during the heating and stirring process.

[0020] In a further embodiment, the crude ammonium salt solution, the first crude aluminum hydroxide, the solid slurry, the sodium thiosulfate, and the second crude aluminum hydroxide are all separated by filtration using a filtration device, wherein the filtration device is one of the following physical filtration equipment: a filter screen, a filter cloth, a filter paper, and a filter filter.

[0021] In a further embodiment, the neutralizing solution is one of dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, carbonic acid, and acetic acid, wherein the mass fraction of the acid in the neutralizing solution is 2-85%.

[0022] In a further embodiment, the mass ratio of the ash residue to the sodium-rich salt is 20:(1-3).

[0023] In a further embodiment, during the crystallization evaporation process in the first and second evaporators, water vapor is introduced into a steam circulation and heat circulation system, wherein the water liquefied after the steam passes through the circulation system can be used in the circulation system.

[0024] The present invention has the following beneficial effects:

[0025] 1. The process of this invention can produce crude aluminum hydroxide, crude ammonium salt, sodium-rich salt, antifreeze concrete and roadbed material additives;

[0026] 2. The process of this invention can realize the recycling and reuse of waste residue, wastewater and waste gas, which not only solves the problem of pollution of "three wastes", but also realizes the efficient utilization of secondary aluminum ash. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the process flow according to an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] The following disclosure provides many different embodiments or examples for implementing different structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; this repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0030] A method for comprehensive utilization of secondary aluminum ash solid waste includes the following steps:

[0031] Includes the following steps:

[0032] Prepare appropriate proportions of secondary aluminum ash and sodium hydroxide, add appropriate amount of water, heat and stir to react, and generate gaseous products and solid slurry;

[0033] The gaseous product is passed through a deammoniation solution to undergo a deammoniation reaction, and the gaseous product after the deammoniation reaction is collected. The deammoniation solution after the deammoniation reaction is filtered to obtain a crude ammonium salt solution and a first crude aluminum hydroxide. The crude ammonium salt solution is evaporated and crystallized to obtain crude ammonium salt, and the first crude aluminum hydroxide is collected.

[0034] The solid slurry is reacted with an appropriate amount of sodium hydroxide by secondary heating and stirring.

[0035] The reacted solid slurry is filtered to obtain filtrate and ash residue. The filtrate is then neutralized with a neutralizing liquid of a certain proportion to obtain neutralized slurry.

[0036] The slurry was filtered and neutralized to obtain sodium fluorocarbonate solution and second crude aluminum hydroxide. The sodium fluorocarbonate solution was evaporated and crystallized to obtain sodium fluorocarbonate, and the second crude aluminum hydroxide was collected.

[0037] Sodium thiocyanate and ash are mixed in a certain ratio.

[0038] In a further embodiment of this example, the mass ratio of the secondary aluminum ash to sodium hydroxide is 1:(1-5), wherein the mass ratio of sodium hydroxide is 5-40%, the stirring temperature is 10-95℃, the stirring time is 10-720min, and nitrogen or inert gas is purged online during the heating and stirring process.

[0039] It should be noted that: during the reaction process, inert gas or nitrogen is purged online, which can immediately purge the gaseous products generated by the reaction into the deammoniation solution for deammoniation treatment, thus avoiding the accumulation of a large amount of hydrogen during the reaction process and thus avoiding danger.

[0040] Furthermore, online purging can result in a lower concentration of ammonia gas in the deammoniation solution at the same time, reducing the deammoniation pressure of the deammoniation solution and making it easier to carry out the deammoniation reaction in the gaseous material, thereby ensuring system safety and the full absorption of ammonia.

[0041] In a further embodiment of this example, the deammoniation solution is one of dilute sulfuric acid, dilute hydrochloric acid, dilute nitric acid, and aluminum sulfate.

[0042] In a further embodiment of this invention, the gas after the ammonia removal reaction is mixed with air a second time in a certain proportion and then transported to the combustion power generation device.

[0043] It should be noted that the main components of the deammoniation-treated mixed gas are hydrogen and nitrogen. It is mixed with air in a certain proportion and then transported to the combustion power generation unit. The electricity and heat generated are mainly used for the mechanical transmission and heat exchange system of the entire system.

[0044] In a further embodiment of this example, the mass ratio of the solid slurry to sodium hydroxide is 1:(1-5), wherein the mass ratio of sodium hydroxide is 5-40%, the stirring temperature is 10-95℃, the stirring time is 10-720min, and nitrogen or inert gas is purged online during the heating and stirring process.

[0045] In a further embodiment of this example, the crude ammonium salt solution, the first crude aluminum hydroxide, the solid slurry, the sodium thiosulfate, and the second crude aluminum hydroxide are all separated by filtration using a filtration device. The filtration device is one of the following physical filtration equipment: a filter screen, a filter cloth, a filter paper, and a filter filter.

[0046] In a further embodiment of this invention, the neutralizing solution is one of dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, carbonic acid, and acetic acid, wherein the mass fraction of acid in the neutralizing solution is 2-85%.

[0047] In a further embodiment of this example, the mass ratio of the ash residue to the sodium-rich salt is 20:(1-3).

[0048] In a further embodiment of this invention, water vapor during the crystallization evaporation process in the first and second evaporators is introduced into a steam circulation and heat circulation system, wherein the water liquefied after the steam passes through the circulation system can be used in the circulation system.

[0049] It should be noted that the equipment required in this process includes: four reaction vessels, two evaporators and a mixer. The secondary aluminum ash and a certain proportion of sodium hydroxide are heated and stirred to react, and inert gas or nitrogen is purged online. The gaseous products are reacted with the deammoniation solution to undergo a deammoniation reaction. The solid slurry is reacted with a certain proportion of sodium hydroxide to undergo a secondary heating and stirring reaction. The filtrate is reacted with a certain proportion of neutralization solution to undergo a neutralization reaction. These reactions are carried out in the corresponding reaction vessels.

[0050] In the following embodiments, the stirred heating reactor, ammonia removal tank, sodium hydroxide treatment tank, and neutralization tank are all reaction vessels, and are described separately for easy distinction and understanding.

[0051] The secondary aluminum ash and a certain proportion of sodium hydroxide are heated and stirred to react, and inert gas or nitrogen is purged online in the heated and stirred reactor.

[0052] The gaseous products undergo a deammoniation reaction with the deammoniation solution in a deammoniation tank.

[0053] The solid slurry is subjected to a secondary heating and stirring reaction with a certain proportion of sodium hydroxide in a sodium hydroxide treatment tank;

[0054] The neutralization reaction between the filtrate and a neutralizing solution of a certain proportion is carried out in a neutralization tank.

[0055] Example 1

[0056] Step (1) A certain aluminum rod factory weighed 1000g of aluminum ash and 3000g of sodium hydroxide (30wt%) and placed them in a reactor to mix, stir and heat. The heating temperature was 20℃ and the heating time was 120min.

[0057] Step (2) The mixed gas in the stirring and heating reactor is fed into the ammonia removal tank to remove ammonia from the mixed gas. The solution in the ammonia removal tank is aluminum sulfate. At the same time, nitrogen is purged online in the waste gas recovery system to ensure system safety and that ammonia is fully absorbed.

[0058] In step (3), the main components of the deammoniation-treated mixed gas are hydrogen and nitrogen. It is then mixed with air in a certain proportion and transported to the combustion power generation unit. The electricity and heat generated are mainly used for the mechanical transmission and heat exchange system of the entire system.

[0059] Step (4) involves transferring the solid slurry generated in the stirred and heated reactor back into the sodium hydroxide treatment tank for secondary stirring and reaction. 3000g of sodium hydroxide (40wt%) is placed in the reactor, mixed, stirred, and heated at 20℃ for 120min.

[0060] Step (5) involves filtering the solid slurry product from step (4) to obtain ash and filtrate, using a physical filter screen.

[0061] Step (6) involves transferring the filtrate from step (5) to a neutralization tank for reaction to obtain a solid slurry. The neutralization tank contains a sufficient amount of 10wt% dilute hydrochloric acid.

[0062] The solid slurry product in step (4) is filtered to obtain crude aluminum hydroxide and filtrate, wherein a physical filter screen is used for filtration.

[0063] In step (7), the solid slurry from step (6) is separated to obtain crude aluminum hydroxide and sodium-rich salt filtrate.

[0064] In step (8), the sodium-rich salt filtrate from step (7) is sent to the evaporator to separate the crude sodium salt and the system circulating water.

[0065] Among them, ash and sodium-rich salt in a mass ratio of 10:1 are used to prepare antifreeze concrete and roadbed material additives.

[0066] The yield of crude aluminum hydroxide produced from secondary aluminum ash was 99.23%.

[0067] Asphalt concrete, ash, and sodium-rich salt were mixed in a mass ratio of 100:10:1 to prepare subgrade material A1, and asphalt concrete was used to prepare subgrade material A2. After five freeze-thaw cycles, their freeze-thaw resistance coefficients were 85% and 78%, respectively.

[0068] Example 2

[0069] Step (1) A certain aluminum rod factory weighed 1000g of aluminum ash and 2000g of sodium hydroxide (40wt%) and placed them in a reactor to mix, stir and heat. The heating temperature was 55℃ and the heating time was 60min.

[0070] Step (2) The mixed gas in the stirring and heating reactor is fed into the ammonia removal tank to remove ammonia from the mixed gas. The solution in the ammonia removal tank is aluminum sulfate. At the same time, nitrogen is purged online in the waste gas recovery system to ensure system safety and that ammonia is fully absorbed.

[0071] In step (3), the main components of the deammoniation-treated mixed gas are hydrogen and nitrogen. It is then mixed with air in a certain proportion and transported to the combustion power generation unit. The electricity and heat generated are mainly used for the mechanical transmission and heat exchange system of the entire system.

[0072] Step (4) involves transferring the solid slurry generated in the stirred and heated reactor back into the sodium hydroxide treatment tank for secondary stirring and reaction. 2000g of sodium hydroxide (40wt%) is placed in the reactor, mixed, stirred, and heated at 55℃ for 60min.

[0073] Step (5) involves filtering the solid slurry product from step (4) to obtain ash and filtrate, using a physical filter screen.

[0074] Step (6) involves transferring the filtrate from step (5) to a neutralization tank for reaction to obtain a solid slurry. The neutralization tank contains a sufficient amount of 10wt% dilute hydrochloric acid.

[0075] The solid slurry product in step (4) is filtered to obtain crude aluminum hydroxide and filtrate, wherein a physical filter screen is used for filtration.

[0076] In step (7), the solid slurry from step (6) is separated to obtain crude aluminum hydroxide and sodium-rich salt filtrate.

[0077] In step (8), the sodium-rich salt filtrate from step (7) is sent to the evaporator to separate the crude sodium salt and the system circulating water.

[0078] Among them, ash and sodium-rich salt in a mass ratio of 4:1 are used to prepare antifreeze concrete and roadbed material additives.

[0079] The yield of crude aluminum hydroxide produced from secondary aluminum ash was 99.50%.

[0080] Asphalt concrete, ash residue and sodium-rich salt were mixed in a mass ratio of 100:4:1 to prepare subgrade material B1, and asphalt concrete was used to prepare subgrade material B2. After five freeze-thaw cycles, their freeze-thaw resistance coefficients were 90% and 85%, respectively.

[0081] Example 3

[0082] Step (1) Weigh 1000g of aluminum ash and 5000g of sodium hydroxide (5wt%) into a reactor, mix and heat them at 90℃ for 120min.

[0083] Step (2) The mixed gas in the stirring and heating reactor is fed into the ammonia removal tank to remove ammonia from the mixed gas. The solution in the ammonia removal tank is aluminum sulfate. At the same time, nitrogen is purged online in the waste gas recovery system to ensure system safety and that ammonia is fully absorbed.

[0084] In step (3), the main components of the deammoniation-treated mixed gas are hydrogen and nitrogen. It is then mixed with air in a certain proportion and transported to the combustion power generation unit. The electricity and heat generated are mainly used for the mechanical transmission and heat exchange system of the entire system.

[0085] Step (4) involves transferring the solid slurry generated in the stirred and heated reactor back into the sodium hydroxide treatment tank for secondary stirring and reaction. 5000g of sodium hydroxide (5wt%) is placed in the reactor, mixed, stirred, and heated at 90℃ for 120min.

[0086] Step (5) involves filtering the solid slurry product from step (4) to obtain ash and filtrate, using a physical filter screen.

[0087] Step (6) involves transferring the filtrate from step (5) to a neutralization tank for reaction to obtain a solid slurry. The neutralization tank contains a sufficient amount of 10wt% dilute hydrochloric acid.

[0088] The solid slurry product in step (4) is filtered to obtain crude aluminum hydroxide and filtrate, wherein a physical filter screen is used for filtration.

[0089] In step (7), the solid slurry from step (6) is separated to obtain crude aluminum hydroxide and sodium-rich salt filtrate.

[0090] In step (8), the sodium-rich salt filtrate from step (7) is sent to the evaporator to separate the crude sodium salt and the system circulating water.

[0091] Among them, ash and sodium-rich salt in a mass ratio of 5:1 are used to prepare antifreeze concrete and roadbed material additives.

[0092] The yield of crude aluminum hydroxide produced from secondary aluminum ash was 99.10%.

[0093] Roadbed material C1 was prepared by mixing cement concrete, ash, and sodium-rich salt in a mass ratio of 100:4:1, and roadbed material C2 was prepared by mixing cement concrete. After five freeze-thaw cycles, their frost resistance coefficients were 89% and 82%, respectively.

[0094] Example 4

[0095] Step (1) Weigh 1000g of aluminum ash and 5000g of sodium hydroxide (5wt%) in a certain aluminum alloy plant, place them in a reactor, mix and stir, and heat them. The heating temperature is 90℃ and the heating time is 120min.

[0096] Step (2) The mixed gas in the stirring and heating reactor is fed into the ammonia removal tank to remove ammonia from the mixed gas. The solution in the ammonia removal tank is aluminum sulfate. At the same time, nitrogen is purged online in the waste gas recovery system to ensure system safety and that ammonia is fully absorbed.

[0097] In step (3), the main components of the deammoniation-treated mixed gas are hydrogen and nitrogen. It is then mixed with air in a certain proportion and transported to the combustion power generation unit. The electricity and heat generated are mainly used for the mechanical transmission and heat exchange system of the entire system.

[0098] Step (4) involves transferring the solid slurry generated in the stirred and heated reactor back into the sodium hydroxide treatment tank for secondary stirring and reaction. 5000g of sodium hydroxide (5wt%) is placed in the reactor, mixed, stirred, and heated at 90℃ for 120min.

[0099] Step (5) involves filtering the solid slurry product from step (4) to obtain ash and filtrate, using a physical filter screen.

[0100] Step (6) involves transferring the filtrate from step (5) to a neutralization tank for reaction to obtain a solid slurry. The neutralization tank contains a sufficient amount of 10wt% dilute hydrochloric acid.

[0101] The solid slurry product in step (4) is filtered to obtain crude aluminum hydroxide and filtrate, wherein a physical filter screen is used for filtration.

[0102] In step (7), the solid slurry from step (6) is separated to obtain crude aluminum hydroxide and sodium-rich salt filtrate.

[0103] In step (8), the sodium-rich salt filtrate from step (7) is sent to the evaporator to separate the crude sodium salt and the system circulating water.

[0104] Among them, ash and sodium-rich salt in a mass ratio of 5:1 are used to prepare antifreeze concrete and roadbed material additives.

[0105] The yield of crude aluminum hydroxide produced from secondary aluminum ash was 99.12%.

[0106] Roadbed material D1 was prepared by mixing cement concrete, ash, and sodium-rich salt in a mass ratio of 100:20:1, and roadbed material D2 was prepared by mixing cement concrete. After five freeze-thaw cycles, their freeze-thaw resistance coefficients were 82% and 75%, respectively.

[0107] Example 5

[0108] Step (1) A certain aluminum rod factory weighed 1000g of aluminum ash and 2500g of sodium hydroxide (35wt%) and placed them in a reactor to mix, stir and heat. The heating temperature was 90℃ and the heating time was 120min.

[0109] Step (2) The mixed gas in the stirring and heating reactor is fed into the ammonia removal tank to remove ammonia from the mixed gas. The solution in the ammonia removal tank is aluminum sulfate. At the same time, nitrogen is purged online in the waste gas recovery system to ensure system safety and that ammonia is fully absorbed.

[0110] In step (3), the main components of the deammoniation-treated mixed gas are hydrogen and nitrogen. It is then mixed with air in a certain proportion and transported to the combustion power generation unit. The electricity and heat generated are mainly used for the mechanical transmission and heat exchange system of the entire system.

[0111] Step (4) involves transferring the solid slurry generated in the stirred and heated reactor back into the sodium hydroxide treatment tank for secondary stirring and reaction. 2500g of sodium hydroxide (35wt%) is placed in the reactor, mixed, stirred, and heated at 90℃ for 120min.

[0112] Step (5) involves filtering the solid slurry product from step (4) to obtain ash and filtrate, using a physical filter screen.

[0113] Step (6) involves transferring the filtrate from step (5) to a neutralization tank for reaction to obtain a solid slurry. The neutralization tank contains a sufficient amount of 10wt% dilute hydrochloric acid.

[0114] The solid slurry product in step (4) is filtered to obtain crude aluminum hydroxide and filtrate, wherein a physical filter screen is used for filtration.

[0115] In step (7), the solid slurry from step (6) is separated to obtain crude aluminum hydroxide and sodium-rich salt filtrate.

[0116] In step (8), the sodium-rich salt filtrate from step (7) is sent to the evaporator to separate the crude sodium salt and the system circulating water.

[0117] Among them, ash and sodium-rich salt in a mass ratio of 5:1 are used to prepare antifreeze concrete and roadbed material additives.

[0118] The yield of crude aluminum hydroxide produced from secondary aluminum ash was 99.36%.

[0119] Roadbed material E1 was prepared by mixing lime soil, ash residue, and sodium-rich salt in a mass ratio of 100:20:3, and roadbed material E2 was prepared by mixing lime soil. After five freeze-thaw cycles, their freeze-thaw resistance coefficients were 87% and 81%, respectively.

[0120] Table 1 below is a data and materials table for Examples 1-5.

[0121] Table 1

[0122]

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for comprehensive utilization of secondary aluminum ash solid waste, characterized in that, Includes the following steps: Prepare appropriate proportions of secondary aluminum ash and sodium hydroxide, add appropriate amount of water, heat and stir to react, and generate gaseous products and solid slurry; The gaseous product is passed through a deammoniation solution to undergo a deammoniation reaction, and the gaseous product after the deammoniation reaction is collected. The deammoniation solution after the deammoniation reaction is filtered to obtain a crude ammonium salt solution and a first crude aluminum hydroxide. The crude ammonium salt solution is evaporated and crystallized to obtain crude ammonium salt, and the first crude aluminum hydroxide is collected. The solid slurry is reacted with an appropriate amount of sodium hydroxide by secondary heating and stirring. The reacted solid slurry is filtered to obtain filtrate and ash residue. The filtrate is then neutralized with a neutralizing liquid of a certain proportion to obtain neutralized slurry. The slurry was filtered and neutralized to obtain sodium fluorocarbonate solution and second crude aluminum hydroxide. The sodium fluorocarbonate solution was evaporated and crystallized to obtain sodium fluorocarbonate, and the second crude aluminum hydroxide was collected. Sodium thiocyanate and ash are mixed in a certain ratio.

2. The method for comprehensive utilization of secondary aluminum ash solid waste according to claim 1, characterized in that, The mass ratio of the secondary aluminum ash to sodium hydroxide is 1:(1-5), wherein the mass ratio of sodium hydroxide is 5-40%, the stirring temperature is 10-95℃, the stirring time is 10-720min, and nitrogen or inert gas is purged online during the heating and stirring process.

3. The method for comprehensive utilization of secondary aluminum ash solid waste according to claim 1, characterized in that, The deammoniation solution is one of dilute sulfuric acid, dilute hydrochloric acid, dilute nitric acid, or aluminum sulfate.

4. The method for comprehensive utilization of secondary aluminum ash solid waste according to claim 1, characterized in that, The gas, after undergoing the deammoniation reaction, is mixed with air in a certain proportion and then transported to the combustion power generation unit.

5. The method for comprehensive utilization of secondary aluminum ash solid waste according to claim 1, characterized in that, The mass ratio of the solid slurry to sodium hydroxide is 1:(1-5), wherein the mass ratio of sodium hydroxide is 5-40%, the stirring temperature is 10-95℃, the stirring time is 10-720min, and nitrogen or inert gas is purged online during the heating and stirring process.

6. The method for comprehensive utilization of secondary aluminum ash solid waste according to claim 1, characterized in that, The crude ammonium salt solution, the first crude aluminum hydroxide, the solid slurry, the sodium thiosulfate, and the second crude aluminum hydroxide are all separated by filtration using a filtration device, wherein the filtration device is one of the following physical filtration equipment: filter screen, filter cloth, filter paper, and filter.

7. The method for comprehensive utilization of secondary aluminum ash solid waste according to claim 1, characterized in that, The neutralizing solution is one of dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, carbonic acid, and acetic acid, wherein the mass fraction of acid in the neutralizing solution is 2-85%.

8. The method for comprehensive utilization of secondary aluminum ash solid waste according to claim 1, characterized in that, The mass ratio of the ash residue to the sodium-rich salt is 20:(1-3).

9. The method for comprehensive utilization of secondary aluminum ash solid waste according to claim 1, characterized in that, During the crystallization evaporation process in the first and second evaporators, water vapor is introduced into the steam circulation and heat circulation system, where the water liquefied after the steam passes through the circulation system can be used in the circulation system.

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