A method and system for comprehensive treatment of harmless aluminum ash and resource utilization

Abstract

The present invention relates to the field of environmental protection treatment technology, and specifically discloses a method and system for the harmless resource utilization comprehensive treatment of aluminum ash, the method comprising: S1: setting screening parameters according to the physical characteristics of the aluminum ash to be treated and a correlation model, controlling the screening equipment to remove large-particle impurities and metal aluminum blocks, and obtaining pretreated aluminum ash. S2: determining water washing parameters according to the water-soluble salt content in the pretreated aluminum ash and a correlation model, controlling the water washing equipment for water washing, and obtaining salt-containing wastewater and aluminum ash. S3: evaporating and crystallizing the wastewater, dynamically adjusting the parameters until no salts are crystallized, and recovering the salts. S4: mixing the pretreated aluminum ash, water, and additives in a reactor according to a preset proportion for hydrolysis, constructing a digital twin model, and collecting ammonia with a water absorption device to obtain recovered ammonia and hydrolysis products. S5: acid leaching the hydrolysis product to obtain a valuable metal salt solution and residue, and harmlessly treating the residue; thereby realizing a complete process from resource recovery and utilization to harmless treatment of aluminum ash.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection treatment, and in particular to a method and system for the harmless and resource-based comprehensive treatment of aluminum ash. Background Art

[0002] Amidst the booming aluminum industry, aluminum ash, a solid waste generated during aluminum smelting and processing, is experiencing increasing production. Proper handling of aluminum ash is crucial to the sustainable development of the industry, not only for environmental protection but also for efficient resource utilization. Aluminum ash contains valuable components such as metallic aluminum and aluminum oxide, as well as hazardous substances such as fluorides and cyanides. Improper disposal not only wastes resources but can also cause serious pollution to the soil, water, and air ecosystems, endangering human health. Therefore, developing a comprehensive, harmless, and resource-based treatment method and system for aluminum ash reduction, harmlessness, and resource utilization has become a research priority. Currently, conventional technologies for treating aluminum ash include physical separation and chemical treatment. Physical separation techniques, such as screening and magnetic separation, aim to separate valuable components such as metallic aluminum from the ash, while chemical treatment methods, such as acid leaching and alkaline leaching, are used to extract valuable metals from the ash. However, these conventional technologies often operate independently and lack a systematic and comprehensive approach. With increasingly stringent environmental protection requirements and the growing popularity of resource recycling, the development of a comprehensive treatment method and system that can comprehensively and efficiently render aluminum ash harmless and fully recover its valuable components holds great promise. This approach not only effectively addresses the environmental issues associated with aluminum ash but also creates significant economic benefits for the aluminum industry, driving its development towards a green and sustainable path.

[0003] However, conventional treatments do not fully integrate the physical characteristics and properties of aluminum ash with the relationship between the treatment process parameters, and cannot accurately set the parameters of the screening equipment. It is difficult to effectively remove large-particle impurities and metal aluminum blocks, which affects the subsequent treatment effect. For the treatment of water-soluble salts in aluminum ash, the control parameters of the washing equipment are not determined based on their content and related correlation models. The washing effect is poor, which may lead to incomplete removal of water-soluble salts or excessive washing, resulting in waste of resources. When recovering salt substances by evaporation and crystallization of wastewater, there is a lack of a mechanism for dynamically adjusting the evaporation and crystallization parameters, which cannot ensure that the salt substances are fully crystallized and recovered, reducing the efficiency of resource recovery. When conducting the aluminum ash hydrolysis reaction, a digital twin model is not constructed to monitor and optimize the reaction in real time, making it difficult to accurately grasp the reaction process, which is not conducive to the efficient recovery of ammonia and hydrolysis products. The existing treatment methods fail to organically combine the various links of aluminum ash treatment to achieve a comprehensive balance between harmlessness and resource utilization. The harmless treatment of the final residue may also be imperfect, posing a risk of environmental pollution.

[0004] Therefore, the present invention proposes a method and system for the comprehensive treatment of harmless and resourceful aluminum ash. Summary of the Invention

[0005] The present invention provides a method and system for the harmless resource utilization of aluminum ash. This method sets screening parameters based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing parameters, removes large-particle impurities and metal aluminum blocks, and accurately pre-treats to improve the efficiency of subsequent treatment and product purity. The control parameters of the water washing equipment are determined by the water-soluble salt content of the aluminum ash after pre-treatment and the correlation model, and the water-soluble salts are separated by water washing. The wastewater is evaporated and crystallized and the parameters are dynamically adjusted to recover the salt substances to the greatest extent and reduce the salt residue in the wastewater. The pre-treated aluminum ash, water and additives are mixed according to a preset ratio to carry out a hydrolysis reaction, and a digital twin model is constructed to monitor the optimization process in real time. Ammonia is recovered by a water absorption device to improve resource utilization. The hydrolysis product is acid-leached to obtain a valuable metal salt solution, and the residue is finally harmlessly treated to obtain a harmless residue, thereby realizing the complete process of aluminum ash from resource recovery and harmless treatment, which is in line with the concept of green environmental protection and sustainable development.

[0006] The present invention provides a method for the harmless and resource-based comprehensive treatment of aluminum ash, comprising:

[0007] S1: Setting screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing parameters, and controlling the screening equipment based on the screening parameters to remove large particles of impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash;

[0008] S2: Determine control parameters of a water washing device based on the content of water-soluble salts in the screened aluminum ash and a correlation model between aluminum ash characteristics and treatment process parameters, and control the water washing device to wash the screened aluminum ash based on the corresponding control parameters to obtain wastewater containing water-soluble salts and pretreated aluminum ash;

[0009] S3: Evaporating and crystallizing the wastewater containing water-soluble salts, while dynamically adjusting the evaporation and crystallization parameters until the wastewater no longer crystallizes salts, thereby recovering the salts;

[0010] S4: The pretreated aluminum ash, water, and additives are mixed in a reactor according to a preset ratio to produce a hydrolysis reaction, and a digital twin model of the aluminum ash hydrolysis reaction is constructed. At the same time, ammonia generated by the hydrolysis reaction is collected using a water absorption device until the hydrolysis reaction no longer progresses, and the recovered ammonia and hydrolysis products are obtained;

[0011] S5: acid leaching the hydrolyzed product to obtain a recovered valuable metal salt solution and a final residue, and performing harmless treatment on the final residue to obtain a harmless residue.

[0012] Optionally, S1: setting screening parameters of a screening device based on the physical characteristics of the aluminum ash to be processed and a correlation model between the aluminum ash characteristics and the processing parameters, and controlling the screening device based on the screening parameters to remove large particles of impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash, including:

[0013] Obtaining the physical characteristics of the aluminum ash to be processed;

[0014] Establish a correlation model between aluminum ash characteristics and treatment process parameters;

[0015] The aperture and vibration frequency of the screening equipment are set as screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing parameters;

[0016] Based on the screening parameters, the screening equipment is controlled to remove large particle impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash.

[0017] Optionally, S2: determining control parameters of a water washing device based on the content of water-soluble salts in the screened aluminum ash and a correlation model between aluminum ash characteristics and treatment process parameters, and controlling the water washing device to wash the screened aluminum ash based on the corresponding control parameters to obtain wastewater containing water-soluble salts and pretreated aluminum ash, including:

[0018] Obtaining the chemical composition of the sieved aluminum ash;

[0019] Determining the content of water-soluble salts in the screened aluminum ash based on the chemical composition of the screened aluminum ash, and determining control parameters of the water washing equipment based on the content of water-soluble salts in the screened aluminum ash and a correlation model;

[0020] Based on the corresponding control parameters, the water washing equipment is controlled to wash the screened aluminum ash with water to obtain wastewater containing water-soluble salts and pretreated aluminum ash.

[0021] Optionally, S3: evaporating and crystallizing the wastewater containing water-soluble salts, and dynamically adjusting the evaporation and crystallization parameters until the wastewater no longer crystallizes salt substances, thereby recovering the salt substances, including:

[0022] Evaporation and crystallization of wastewater containing water-soluble salts, while monitoring the real-time crystallization rate of salt substances and the real-time distribution morphology of all crystal particles;

[0023] The evaporation crystallization parameters are dynamically adjusted based on the real-time crystallization speed of the salt substance and the real-time distribution morphology of all crystal particles until the wastewater no longer crystallizes salt substances, and the recovered salt substances are obtained.

[0024] Optionally, monitor the real-time crystallization rate of salt substances and the real-time distribution morphology of all crystal particles, including:

[0025] Obtain real-time evaporation and crystallization monitoring video of wastewater, and analyze the real-time number, real-time particle size, and real-time distribution of all crystal particles in the wastewater based on an image segmentation algorithm, and analyze the first real-time crystallization speed of the salt substance based on the real-time number and real-time particle size of all crystal particles;

[0026] Analyze the second real-time crystallization rate of salt substances based on laser scattering method;

[0027] Analyze the third real-time crystallization rate of salt substances based on density monitoring method;

[0028] Analyze the fourth real-time crystallization rate of salt substances based on the conductivity monitoring method;

[0029] determining a crystallization stage of the salt substance based on a first real-time crystallization rate, a second real-time crystallization rate, a third real-time crystallization rate, a fourth real-time crystallization rate, and a real-time distribution morphology of the salt substance;

[0030] The current contribution of each monitoring means is determined based on the crystallization stage of the salt substance, and the real-time crystallization rate of the salt substance is determined based on the first real-time crystallization rate, the second real-time crystallization rate, the third real-time crystallization rate, the fourth crystallization rate and the current contribution of each monitoring means.

[0031] Optionally, the evaporation crystallization parameters are dynamically adjusted based on the real-time crystallization rate of the salt substance and the real-time distribution morphology of all crystal particles until the wastewater no longer crystallizes the salt substance, thereby recovering the salt substance, including:

[0032] Generate the latest spatiotemporal characteristic matrix of all crystal particles based on the real-time crystallization speed of salt substances and the real-time distribution morphology of all crystal particles;

[0033] Simulate the aggregation behavior of all crystal particles in solution based on their real-time distribution morphology and predict the critical supersaturation;

[0034] Based on the latest spatiotemporal characteristic matrix of all crystal particles, critical supersaturation and dynamic optimization model of evaporation crystallization parameters, the evaporation crystallization parameters are dynamically adjusted until the wastewater no longer crystallizes salt substances, and the recovered salt substances are obtained.

[0035] Optionally, based on the real-time crystallization rate of the salt substance and the real-time distribution morphology of all crystal particles, the latest spatiotemporal feature matrix of all crystal particles is generated, including:

[0036] Extract the crystallization rate characteristics of each time step based on the real-time crystallization rate of salt substances;

[0037] Determine all particle groups based on the real-time distribution morphology of all crystal particles, determine the real-time centroid position and real-time distribution range of all particle groups as the real-time position features of all crystal particles, and extract the real-time shape features of all crystal particles;

[0038] Based on the principal component analysis method and the real-time distribution morphology of all crystal particles, the principal axis directions of all crystal particles are determined as the real-time orientation characteristics of all crystal particles;

[0039] The latest spatiotemporal feature matrix of all crystal particles is generated based on the crystallization velocity characteristics of all time steps currently acquired, the real-time position characteristics, real-time shape characteristics, and real-time orientation characteristics of all crystal particles.

[0040] Optionally, S4: mixing the pretreated aluminum ash, water, and additives in a reactor according to a preset ratio to produce a hydrolysis reaction, and constructing a digital twin model of the aluminum ash hydrolysis reaction. At the same time, collecting ammonia generated by the hydrolysis reaction based on a water absorption device until the hydrolysis reaction no longer progresses, thereby obtaining recovered ammonia and hydrolysis products, including:

[0041] The pretreated aluminum ash, water and additives are mixed in a reactor according to a preset ratio to produce a hydrolysis reaction;

[0042] At the same time, the ammonia produced by the hydrolysis reaction is collected based on the water absorption device;

[0043] At the same time, a digital twin model of the aluminum ash hydrolysis reaction is constructed based on the basic reaction parameters and reaction process parameters in the reactor, and the basic reaction parameters in the reactor are optimized and adjusted based on the digital twin model of the aluminum ash hydrolysis reaction until the hydrolysis reaction no longer produces progress, and the recovered ammonia and hydrolysis products are obtained.

[0044] Optionally, S5: acid leaching the hydrolyzed product to obtain a recovered valuable metal salt solution and a final residue, and performing harmless treatment on the final residue to obtain a harmless residue, comprising:

[0045] Conduct composition analysis and structural characterization on the hydrolysis products to determine the occurrence state of valuable metals;

[0046] Determining acid leaching process parameters based on the occurrence state of the valuable metals, and acid leaching the hydrolyzed product based on the acid leaching process parameters to obtain a recovered valuable metal salt solution and a final residue;

[0047] The solidification process of the final residue is adjusted based on an adaptive control algorithm until the residue reaches the harmlessness standard to obtain harmless residue.

[0048] The present invention provides a system for a harmless and resource-based comprehensive treatment method of aluminum ash, comprising:

[0049] The aluminum ash screening end is used to set the screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing process parameters, and control the screening equipment based on the screening parameters to remove large particles of impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash;

[0050] The aluminum ash washing end is used to determine the control parameters of the water washing equipment based on the content of water-soluble salts in the screened aluminum ash and the correlation model between the aluminum ash characteristics and the treatment process parameters, and control the water washing equipment to wash the screened aluminum ash based on the corresponding control parameters to obtain wastewater containing water-soluble salts and pre-treated aluminum ash;

[0051] The salt evaporation and crystallization end is used to evaporate and crystallize wastewater containing water-soluble salts. At the same time, the evaporation and crystallization parameters are dynamically adjusted until the wastewater no longer crystallizes salt substances, and the salt substances are recovered;

[0052] The hydrolysis reaction execution monitoring terminal is used to mix the pretreated aluminum ash, water, and additives in a reactor according to a preset ratio to produce a hydrolysis reaction, and to build a digital twin model of the aluminum ash hydrolysis reaction. At the same time, a water absorption device is used to collect ammonia produced by the hydrolysis reaction until the hydrolysis reaction stops, and then the ammonia and hydrolysis products are recovered;

[0053] The acid leaching, impurity removal and harmless treatment end is used to acid-leach and remove impurities from the hydrolyzate to obtain recovered valuable metal salts and final residue, and to perform harmless treatment on the final residue to obtain harmless residue.

[0054] The beneficial effects of the present invention compared to the prior art are as follows: This method for the harmless resource utilization of aluminum ash sets screening parameters based on the physical characteristics of the aluminum ash to be treated and the correlation model between the aluminum ash characteristics and the treatment process parameters, removes large-particle impurities and metal aluminum blocks, and accurately pre-treats to improve the efficiency of subsequent treatment and product purity. The control parameters of the water washing equipment are determined by the water-soluble salt content of the aluminum ash after pre-treatment and the correlation model, and the water-soluble salts are separated by water washing. The wastewater is evaporated and crystallized and the parameters are dynamically adjusted to recover salt substances to the greatest extent and reduce salt residue in the wastewater. The pre-treated aluminum ash, water and additives are mixed in a preset proportion to carry out a hydrolysis reaction, a digital twin model is constructed to monitor the optimization process in real time, and a water absorption device is used to recover ammonia to improve resource utilization. The hydrolysis product is acid-leached to obtain a valuable metal salt solution, and the residue is finally harmlessly treated to obtain a harmless residue, realizing the complete process of aluminum ash from resource recovery and harmless treatment, which is in line with the concept of green environmental protection and sustainable development.

[0055] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in this application document.

[0056] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0058] Figure 1 Flowchart of the method for comprehensive harmless resource recovery of aluminum ash in an embodiment of the present invention;

[0059] Figure 2 This is a system diagram of the method for comprehensive harmless resource recovery of aluminum ash in an embodiment of the present invention. DETAILED DESCRIPTION

[0060] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0061] Example 1

[0062] The present invention provides a method for the harmless and resource-based comprehensive treatment of aluminum ash. Figure 1 ,include:

[0063] S1: Setting screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing parameters, and controlling the screening equipment based on the screening parameters to remove large particles of impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash;

[0064] S2: Determine control parameters of a water washing device based on the content of water-soluble salts in the screened aluminum ash and a correlation model between aluminum ash characteristics and treatment process parameters, and control the water washing device to wash the screened aluminum ash based on the corresponding control parameters to obtain wastewater containing water-soluble salts and pretreated aluminum ash;

[0065] S3: Evaporating and crystallizing the wastewater containing water-soluble salts, while dynamically adjusting the evaporation and crystallization parameters until the wastewater no longer crystallizes salts, thereby recovering the salts;

[0066] S4: The pretreated aluminum ash, water, and additives are mixed in a reactor according to a preset ratio to produce a hydrolysis reaction, and a digital twin model of the aluminum ash hydrolysis reaction is constructed. At the same time, ammonia generated by the hydrolysis reaction is collected using a water absorption device until the hydrolysis reaction no longer progresses, and the recovered ammonia and hydrolysis products are obtained;

[0067] S5: acid leaching the hydrolyzed product to obtain a recovered valuable metal salt solution and a final residue, and performing harmless treatment on the final residue to obtain a harmless residue.

[0068] In this embodiment, the physical characteristics of the aluminum ash to be processed refer to its physical characteristics, including but not limited to particle size, shape, density, color, and looseness. These characteristics influence subsequent processing. For example, particle size and shape determine the parameters of screening equipment, which helps remove large impurities and aluminum lumps.

[0069] In this example, the aluminum ash characteristics and treatment process parameter correlation model is constructed through big data analysis and machine learning algorithms. It reveals the inherent connection between the physical properties (such as particle size and density) and chemical properties (such as composition and content) of aluminum ash and various process parameters (such as screening parameters, water washing parameters, and evaporation and crystallization parameters) during the treatment process. Utilizing this model, treatment process parameters can be accurately determined based on the characteristics of aluminum ash, improving treatment effectiveness and efficiency.

[0070] In this embodiment, the screening equipment is used to screen aluminum ash, separating large impurities and aluminum lumps from the ash to be processed. A common type of screening equipment is a vibrating screen, which uses vibration to force aluminum ash particles through meshes of varying apertures, achieving separation and providing a relatively pure aluminum ash raw material for subsequent processing.

[0071] In this embodiment, the screening equipment's screening parameters are set based on the physical characteristics of the aluminum ash to be processed and a model correlating the aluminum ash's characteristics with the processing parameters. These parameters are used to control the operation of the screening equipment, primarily including the screening equipment's aperture and vibration frequency. Appropriate screening parameters can effectively remove large impurities and aluminum lumps. For example, for larger aluminum ash particles, a larger aperture and appropriate vibration frequency are required to ensure effective screening.

[0072] In this embodiment, large impurities in the aluminum ash to be processed refer to larger impurities in the aluminum ash that are not the main components of the aluminum ash. These may include stones, soil, and other metal pieces that were introduced during the production process. These impurities will affect the subsequent aluminum ash processing and product quality and must be removed through screening equipment.

[0073] In this example, the water-soluble salt content in the pretreated aluminum ash refers to the amount of water-soluble salts in the aluminum ash after screening and pretreatment. Determining this content is crucial for the subsequent water washing process, as it is used in conjunction with a correlation model to determine the control parameters of the water washing equipment to effectively remove the water-soluble salts.

[0074] In this embodiment, the control parameters of the water washing equipment are determined based on the content of water-soluble salts in the pretreated aluminum ash and a model correlating aluminum ash characteristics with treatment process parameters. These parameters, used to control the operation of the water washing equipment, include washing time, washing water volume, washing temperature, and stirring speed. Appropriate control parameters ensure effective separation of water-soluble salts while avoiding waste of resources caused by excessive washing.

[0075] In this embodiment, wastewater containing water-soluble salts is obtained by washing the pretreated aluminum ash with water, dissolving the water-soluble salts in the aluminum ash. This wastewater requires further treatment to recover the salts through evaporation and crystallization, thereby achieving resource recycling and reducing environmental pollution.

[0076] In this embodiment, the screened aluminum ash is the aluminum ash after the screening equipment removes large impurities and aluminum metal blocks. The aluminum ash at this point is relatively pure, providing a better raw material base for subsequent treatment steps such as water washing and hydrolysis, which is beneficial to improving the overall treatment effect and product purity.

[0077] In this embodiment, evaporation crystallization parameters: During the evaporation crystallization process of wastewater containing water-soluble salts, parameters controlling the crystallization process, such as evaporation temperature, evaporation rate, stirring speed, and crystallization time, can be adjusted. By dynamically adjusting these parameters, sufficient crystallization recovery of the salt can be achieved based on the real-time crystallization rate and crystal particle distribution of the salt.

[0078] In this embodiment, salts are recovered from wastewater containing water-soluble salts by evaporating and crystallizing the salts and dynamically adjusting parameters to allow the salts to crystallize and precipitate, and the resulting product is collected. These recovered salts can be further utilized, achieving resource recycling and reducing waste discharge.

[0079] In this embodiment, the preset ratio refers to the ratio of the pretreated aluminum ash, water, and additives during the mixing reaction in the reactor, determined based on the chemical principles of the aluminum ash hydrolysis reaction and actual processing experience. A suitable preset ratio facilitates the hydrolysis reaction to proceed effectively, improving the efficiency and quality of ammonia and hydrolysis product production.

[0080] In this embodiment, additives are auxiliary substances added to the aluminum ash hydrolysis reaction. Their functions may be to promote the reaction, regulate the reaction rate, change the reaction path, or improve product purity. The specific type and amount of additives should be determined based on the characteristics of the aluminum ash and the purpose of the reaction. For example, certain additives can accelerate the hydrolysis reaction rate, making the reaction more efficient.

[0081] In this embodiment, the hydrolysis reaction is a chemical reaction that occurs when pretreated aluminum ash, water, and additives are mixed in a reactor at predetermined ratios. In this reaction, certain components in the aluminum ash react with water in the presence of the additives, producing hydrolysis products and releasing ammonia. This reaction is a crucial step in the aluminum ash treatment process, facilitating subsequent separation and recovery of components within the ash.

[0082] In this example, the digital twin model of the hydrolysis reaction is a virtual model constructed based on the basic reaction parameters (such as temperature, pressure, and reactant concentration) and reaction process parameters (such as reaction time and product yield) in the reactor. This model corresponds to the actual hydrolysis reaction, simulating and reflecting the actual reaction process. By analyzing this model, the basic reaction parameters in the reactor can be optimized and adjusted, achieving precise control and optimization of the hydrolysis reaction.

[0083] In this embodiment, the water absorption device is used to collect ammonia generated by the hydrolysis reaction. It is designed to take advantage of ammonia's solubility in water. Its structure and operating mode ensure that the ammonia and water come into full contact, allowing the ammonia to dissolve in the water. This achieves the purpose of collecting ammonia, prevents ammonia from being discharged into the environment and causing pollution, and simultaneously achieves resource recovery.

[0084] In this embodiment, ammonia gas generated by the hydrolysis reaction is collected using a water absorption device. During the aluminum ash hydrolysis reaction, the water absorption device operates synchronously, allowing the generated ammonia gas to fully contact the water within the device, dissolving the ammonia gas in the water and then being collected. For example, by passing the ammonia gas through an absorption tower filled with water and using spraying or other methods to increase the contact area and duration between the ammonia gas and the water, the ammonia gas collection efficiency is improved.

[0085] In this embodiment, the hydrolysis reaction no longer produces progress: it means that as the hydrolysis reaction proceeds, when factors such as the decrease in reactant concentration and changes in reaction conditions cause the reaction rate to be extremely slow, almost no new product is generated, or the amount of product generated reaches the expected amount and no longer increases significantly, it is considered that the hydrolysis reaction no longer produces progress, the reaction can be stopped and subsequent processing can be carried out.

[0086] In this embodiment, the hydrolysis product is the substance produced after the aluminum ash hydrolysis reaction is completed. Its composition and properties depend on factors such as the original composition of the aluminum ash, reaction conditions, and additives. The hydrolysis product is further treated by acid leaching to extract the valuable metals and to render the residue harmless.

[0087] In this embodiment, the valuable metal salt solution is recovered: After the hydrolyzate is acid-leached, the valuable metals react with the acid and dissolve in the solution to form a solution. This solution contains recyclable valuable metal salts. Through subsequent separation and purification processes, valuable metals can be obtained, achieving resource recovery.

[0088] In this embodiment, the final residue is the substance remaining after acid leaching the hydrolyzed product that does not react with the acid. These residues may still contain some harmful substances and need to be treated to ensure that they do not pollute the environment.

[0089] In this embodiment, the final residue is subjected to harmless treatment to obtain harmless residue: a specific treatment process is adopted, such as adjusting the curing process based on an adaptive control algorithm, adding a curing agent to the residue and controlling relevant parameters (such as temperature, time, etc.), so that the harmful substances in the residue are fixed or converted into a harmless form, meeting the harmlessness standard, and obtaining a harmless residue that does not pollute the environment.

[0090] Example 2

[0091] Based on Example 1, S1: setting screening parameters of a screening device based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing parameters, and controlling the screening device based on the screening parameters to remove large particles of impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash, including:

[0092] Obtaining the physical characteristics of the aluminum ash to be processed;

[0093] Establish a correlation model between aluminum ash characteristics and treatment process parameters;

[0094] The aperture and vibration frequency of the screening equipment are set as screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing parameters;

[0095] Based on the screening parameters, the screening equipment is controlled to remove large particle impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash.

[0096] In this embodiment, obtaining the physical properties of the aluminum ash to be processed is an important starting point, providing a basis for subsequent processes, as follows:

[0097] Particle characteristics: Size: Use a particle size analyzer to determine the size and distribution of aluminum ash particles through laser scattering or screening principles. This is critical for setting the screening aperture, such as determining the sieve aperture size based on the particle size range to separate large particle impurities.

[0098] Shape: Use a microscope or image analysis to determine the shape of aluminum ash particles. Irregular shapes may affect screening, and the vibration frequency needs to be adjusted to ensure the effect.

[0099] Density characteristics: Using a density meter to measure the density of aluminum ash based on the Archimedes principle can help determine the composition and is also used in gravity separation processes.

[0100] Flowability: Observe the flow of aluminum ash in a specific device, such as measuring the outflow time or flow rate through a funnel to evaluate the fluidity. Poor fluidity may require pretreatment to facilitate subsequent processing.

[0101] Looseness characteristics: The looseness is determined by measuring the porosity or bulk density under natural stacking. The looseness affects the contact and reaction efficiency of aluminum ash with other substances.

[0102] In this example, a correlation model between aluminum ash characteristics and processing parameters is established: Establishing this correlation model is a key step in optimizing the overall aluminum ash processing process. First, a large amount of aluminum ash sample data from different sources and batches must be collected. This data covers various physical properties (such as particle size distribution, density, and shape) and chemical properties (such as chemical composition and content, such as the proportion of aluminum oxide, metallic aluminum, and water-soluble salts).

[0103] Next, big data analytics techniques are used to deeply mine this vast amount of data, identifying underlying patterns and relationships between aluminum ash characteristics and different processing parameters. For example, analysis revealed that aluminum ash within a certain particle size range, at a specific sieve aperture and vibration frequency, is more effective in separating large impurities and aluminum metal lumps; or that aluminum ash with a certain chemical composition is most effective in removing water-soluble salts under specific washing conditions of time, temperature, and water volume.

[0104] Then, these data and the discovered patterns are learned and modeled with the help of machine learning algorithms. Common algorithms such as linear regression, decision trees, neural networks, etc., can accurately reflect the quantitative or qualitative relationship between aluminum ash characteristics and treatment process parameters by continuously training and optimizing the model. The association model finally constructed can predict the most suitable treatment process parameters based on the input aluminum ash characteristic data, providing strong support for the precise control of subsequent aluminum ash treatment processes. In this embodiment, the aperture and vibration frequency of the screening equipment are key parameters for controlling the screening effect. The aperture determines the maximum size of the particles that can pass through the screen, and the vibration frequency affects the movement state of the aluminum ash particles on the screen and the screening efficiency.

[0105] The choice of pore size is based on the physical characteristics of the aluminum ash to be processed and the established correlation model between aluminum ash characteristics and processing parameters. If the large impurities and aluminum lumps to be removed from the aluminum ash are large, the correlation model will indicate the selection of a sieve with a larger pore size to ensure that these large particles can be intercepted and separated. Conversely, if the impurity particles are relatively small, a sieve with a smaller pore size is selected to achieve finer screening and ensure that the aluminum ash particle size after pretreatment meets the requirements of subsequent processing.

[0106] Vibration frequency is equally important. A suitable vibration frequency can evenly distribute the aluminum ash particles on the screen and cause them to bounce continuously, promoting the passage of small particles through the sieve holes and preventing particles from clogging the screen. If the vibration frequency is too low, the aluminum ash particles will not move sufficiently, which may lead to low screening efficiency and prevent some small particles from passing through the screen in time. If the vibration frequency is too high, the aluminum ash particles may bounce too violently, which is also detrimental to the screening effect and may even damage the screening equipment. For example, for aluminum ash with larger particles and better fluidity, the vibration frequency can be appropriately increased to speed up the screening speed. For aluminum ash with higher viscosity or smaller particles that are prone to agglomeration, a relatively low and stable vibration frequency should be selected to ensure smooth screening. In short, precisely adjusting the aperture and vibration frequency of the screening equipment according to the characteristics of the aluminum ash can effectively remove large impurities and metal aluminum blocks, improve the quality of the aluminum ash after pretreatment, and lay a good foundation for subsequent processing links.

[0107] Example 3

[0108] Based on Example 1, S2: determining control parameters of a water washing device based on the content of water-soluble salts in the screened aluminum ash and a correlation model between aluminum ash characteristics and treatment process parameters, and controlling the water washing device to wash the screened aluminum ash based on the corresponding control parameters to obtain wastewater containing water-soluble salts and pretreated aluminum ash, including:

[0109] Obtaining the chemical composition of the sieved aluminum ash;

[0110] Determining the content of water-soluble salts in the screened aluminum ash based on the chemical composition of the screened aluminum ash, and determining control parameters of the water washing equipment based on the content of water-soluble salts in the screened aluminum ash and a correlation model;

[0111] Based on the corresponding control parameters, the water washing equipment is controlled to wash the screened aluminum ash with water to obtain wastewater containing water-soluble salts and pretreated aluminum ash.

[0112] In this embodiment, determining the chemical composition of the sieved aluminum ash is a key step in subsequent processing. Various chemical analysis methods are employed, such as X-ray fluorescence spectroscopy (XRF), a spectral analysis technique, to quickly determine the types and approximate contents of elements in the aluminum ash, understanding the ratios of major elements such as aluminum, iron, and calcium. Chemical titration is used to precisely and quantitatively analyze specific components, such as alumina content. Chromatographic analysis may also be used to detect organic components. These methods provide a comprehensive and accurate understanding of the chemical composition of the sieved aluminum ash, providing a basis for determining the content of water-soluble salts and selecting treatment processes.

[0113] After clarifying the chemical composition of the sieved aluminum ash, the content of water-soluble salts can be determined. First, based on the chemical composition, identify components that may exist as water-soluble salts, such as sodium chloride and potassium chloride. Then, employ appropriate experimental methods for determination. For example, for chloride salts, dissolve the aluminum ash sample in deionized water and stir to completely dissolve the water-soluble salts. Then, titrate using precipitation titration with a standard silver nitrate solution, and calculate the chloride content based on the volume of standard solution consumed. For other water-soluble salts, select specific analytical methods for quantitative determination to accurately determine their content, providing an important basis for determining washing process parameters.

[0114] After knowing the water-soluble salt content in the screened aluminum ash, the control parameters of the water washing equipment are determined by combining the pre-established correlation model between the aluminum ash characteristics and the treatment process parameters. This correlation model is constructed by big data analysis and machine learning algorithms, and reflects the relationship between the aluminum ash characteristics (water-soluble salt content) and the water washing process parameters. For example, if the correlation model shows that when the water-soluble salt content is high, a longer water washing time, a larger water washing volume, and an appropriate increase in the water washing temperature and stirring speed are required to effectively remove it, then based on the current water-soluble salt content, the corresponding water washing time, water washing volume, water washing temperature, stirring speed and other control parameters are obtained from the correlation model to ensure that water washing can fully remove water-soluble salts while avoiding waste of resources or excessive water washing that affects subsequent processing.

[0115] Based on the control parameters of the water washing equipment determined from the correlation model, the water washing equipment is started and operated to wash the screened aluminum ash. The water washing equipment operates for the set washing time, maintaining a suitable amount of wash water in contact with the aluminum ash, controlling the washing temperature, and thoroughly mixing the aluminum ash and water at a specified stirring speed. During this process, the water-soluble salts in the aluminum ash gradually dissolve in the water. After washing, the wastewater containing the water-soluble salts is separated through solid-liquid separation methods such as filtration or precipitation. The aluminum ash, after washing to remove the water-soluble salts, becomes pretreated aluminum ash, providing a suitable raw material for further processing such as hydrolysis reactions.

[0116] Example 4

[0117] Based on Example 1, S3: evaporating and crystallizing the wastewater containing water-soluble salts, and dynamically adjusting the evaporation and crystallization parameters until the wastewater no longer crystallizes salt substances, thereby obtaining recovered salt substances, including:

[0118] Evaporation and crystallization of wastewater containing water-soluble salts, while monitoring the real-time crystallization rate of salt substances and the real-time distribution morphology of all crystal particles;

[0119] The evaporation crystallization parameters are dynamically adjusted based on the real-time crystallization speed of the salt substance and the real-time distribution morphology of all crystal particles until the wastewater no longer crystallizes salt substances, and the recovered salt substances are obtained.

[0120] In this example, evaporation and crystallization of wastewater containing water-soluble salts is a crucial step in the recovery and utilization of these salts. Heating and other methods gradually evaporate the water in the wastewater. As the solvent decreases, the concentration of the salts increases, reaching a supersaturated state and crystallizing. This process requires precise control to ensure efficient and pure salt recovery through crystallization.

[0121] The real-time crystallization rate of a salt substance refers to the rate at which a salt substance crystallizes over time during the evaporation and crystallization process. It is a key indicator for evaluating the progress of the crystallization process and optimizing the process. The real-time crystallization rate is not constant and is affected by various factors, such as evaporation temperature, solution concentration, and stirring speed. By monitoring the crystallization rate in real time, process parameters can be adjusted to maintain the optimal crystallization process. For example, if the crystallization rate is too slow, the evaporation temperature or stirring speed can be appropriately increased to accelerate crystallization.

[0122] The real-time distribution of all crystal particles describes the spatial distribution of all crystallizing salt crystals in the solution at a given moment during the evaporation and crystallization process. This includes information such as the degree of crystal aggregation, uniformity of dispersion, and position in the solution. The real-time distribution of crystal particles can affect the quality and efficiency of crystallization. For example, an uneven distribution of crystal particles can lead to large variations in local supersaturation, affecting the consistency of crystal growth and, in turn, the quality of the recovered salt. By monitoring the real-time distribution, evaporation and crystallization parameters can be dynamically adjusted to achieve more ideal crystallization results.

[0123] Example 5

[0124] Based on Example 4, the real-time crystallization rate of the salt substance and the real-time distribution morphology of all crystal particles are monitored, including:

[0125] Obtain real-time evaporation and crystallization monitoring video of wastewater, and analyze the real-time number, real-time particle size, and real-time distribution of all crystal particles in the wastewater based on an image segmentation algorithm, and analyze the first real-time crystallization speed of the salt substance based on the real-time number and real-time particle size of all crystal particles;

[0126] Analyze the second real-time crystallization rate of salt substances based on laser scattering method;

[0127] Analyze the third real-time crystallization rate of salt substances based on density monitoring method;

[0128] Analyze the fourth real-time crystallization rate of salt substances based on the conductivity monitoring method;

[0129] determining a crystallization stage of the salt substance based on a first real-time crystallization rate, a second real-time crystallization rate, a third real-time crystallization rate, a fourth real-time crystallization rate, and a real-time distribution morphology of the salt substance;

[0130] The current contribution of each monitoring means is determined based on the crystallization stage of the salt substance, and the real-time crystallization rate of the salt substance is determined based on the first real-time crystallization rate, the second real-time crystallization rate, the third real-time crystallization rate, the fourth crystallization rate and the current contribution of each monitoring means.

[0131] In this embodiment, real-time wastewater evaporation and crystallization monitoring video refers to the use of appropriately positioned cameras to continuously record the evaporation and crystallization of wastewater containing water-soluble salts. This video provides intuitive visual data for subsequent analysis, helping to understand the changes in crystal particles during the crystallization process in real time.

[0132] Analyzing the real-time number, size, and distribution of all crystal particles in wastewater using an image segmentation algorithm involves processing each frame of real-time evaporation and crystallization monitoring video using a specialized image segmentation algorithm. This algorithm can separate crystal particles from the background. By measuring and analyzing the segmented image, the total number of crystal particles in the wastewater at that moment, the size of each crystal particle, and their distribution within the solution—for example, whether they are evenly dispersed or locally aggregated—can be determined.

[0133] The first real-time crystallization rate of a salt substance is analyzed based on the real-time number and size of all crystal particles. This is calculated by analyzing the change in the number and size of crystal particles over time. As the crystallization process progresses, the number of crystal particles increases and the particle size also increases. By acquiring the real-time number and size data of crystal particles at different time points and calculating the increase in the number of crystal particles and the change in particle size per unit time, the first real-time crystallization rate of the salt substance within that time period is determined. This reflects the crystallization rate determined by image analysis.

[0134] The laser scattering method analyzes the second real-time crystallization rate of salt substances. This measurement is based on the principle of laser scattering. When laser light is irradiated into wastewater containing crystallizing salts, the salt crystal particles scatter the laser light. Specific laser scattering detection equipment collects and analyzes the intensity, angle, and other characteristics of the scattered light. Based on relevant physical models and algorithms, these scattering characteristics are converted into the crystallization rate of the salt substance, resulting in the second real-time crystallization rate of the salt substance, providing information on the crystallization rate from another perspective.

[0135] The third real-time crystallization rate of salts, analyzed based on density monitoring, infers the crystallization rate by using changes in wastewater density during the salt crystallization process. As salts continue to crystallize, the salt content in the wastewater gradually decreases, and the solution density changes accordingly. By installing a high-precision density sensor in the evaporation crystallization equipment to monitor changes in wastewater density in real time, and using a pre-established model for the relationship between density and crystallization rate, this density change data is converted into the salt crystallization rate, thus providing another dimension of data support for understanding the crystallization process.

[0136] The fourth real-time crystallization rate of salts, analyzed based on conductivity monitoring, is determined because the dissolution and crystallization of salts in water significantly affects the solution's conductivity. During the evaporation and crystallization process, a conductivity sensor measures changes in the wastewater's conductivity in real time. Because conductivity is closely related to the ion concentration of salts in solution, which in turn is closely linked to the salt crystallization process, relevant theories and algorithms are used to convert conductivity changes into the crystallization rate of salts, thereby determining the fourth real-time crystallization rate and providing a more comprehensive understanding of crystallization rates.

[0137] Determining the crystallization stage of a salt substance based on its first, second, third, and fourth real-time crystallization rates and real-time distribution morphology is a comprehensive assessment of the crystallization stage based on multiple data points. Different crystallization stages (such as the nucleation stage, crystal growth stage, and stabilization stage) have different characteristics, and each monitoring method has different abilities to reflect the crystallization rate at different stages. For example, in the nucleation stage, the first real-time crystallization rate obtained based on the image segmentation algorithm may better reflect the rapid increase in the number of crystals; while in the crystal growth stage, the second real-time crystallization rate obtained by the laser scattering method may better reflect the growth of the crystal particle size. By comprehensively analyzing the four crystallization rate data and the real-time distribution morphology of the crystal particles (such as the relatively sparse distribution and rapid increase in the number of crystal particles in the nucleation stage, and the gradually dense distribution and increased particle size in the growth stage), and applying relevant crystallization theories and data analysis methods, the current crystallization stage of the salt substance can be determined more accurately.

[0138] The current contribution of each monitoring method is determined based on the crystallization stage of the salt substance because the data provided by each monitoring method is of different importance to the accurate description of the crystallization rate at different crystallization stages. For example, in the nucleation stage at the beginning of crystallization, the image segmentation algorithm may be the most critical for determining the crystallization rate, because the change in the number of crystal particles at this time is an important basis for judging the crystallization rate. Therefore, the contribution of the first real-time crystallization rate obtained by the image segmentation algorithm at this stage may be relatively high; while in the crystal growth stage, the laser scattering method can more accurately reflect the growth of crystal particle size, so its contribution may be relatively higher. By analyzing the correlation and importance of the data of each monitoring method at different crystallization stages and the actual crystallization process, the contribution ratio of each monitoring method to the determination of the crystallization rate at the current crystallization stage, that is, the current contribution, is determined.

[0139] Determining the real-time crystallization rate of a salt substance based on the first real-time crystallization rate, the second real-time crystallization rate, the third real-time crystallization rate, the fourth crystallization rate, and the current contribution of each monitoring method is a method that comprehensively considers data from multiple monitoring methods. According to the contribution of each monitoring method in the current crystallization stage, the four real-time crystallization rate data are weighted. For example, if the first real-time crystallization rate contribution is w1, the second real-time crystallization rate contribution is w2, the third real-time crystallization rate contribution is w3, and the fourth real-time crystallization rate contribution is w4, and w1+w2+w3+w4=1, then the real-time crystallization rate of the salt substance V=w1×V1+w2×V2+w3×V3+w4×V4, where V1, V2, V3, and V4 are the first, second, third, and fourth real-time crystallization rates, respectively. The real-time crystallization rate obtained in this way can more comprehensively and accurately reflect the actual crystallization rate of the salt substance at the current moment, providing a more reliable basis for dynamically adjusting the evaporation crystallization parameters.

[0140] Example 6

[0141] On the basis of Example 4, the evaporation crystallization parameters are dynamically adjusted based on the real-time crystallization rate of the salt substance and the real-time distribution morphology of all crystal particles until the wastewater no longer crystallizes the salt substance, thereby recovering the salt substance, including:

[0142] Generate the latest spatiotemporal characteristic matrix of all crystal particles based on the real-time crystallization speed of salt substances and the real-time distribution morphology of all crystal particles;

[0143] Simulate the aggregation behavior of all crystal particles in solution based on their real-time distribution morphology and predict the critical supersaturation;

[0144] Based on the latest spatiotemporal characteristic matrix of all crystal particles, critical supersaturation and dynamic optimization model of evaporation crystallization parameters, the evaporation crystallization parameters are dynamically adjusted until the wastewater no longer crystallizes salt substances, and the recovered salt substances are obtained.

[0145] In this embodiment, the latest spatiotemporal feature matrix of all crystal particles is a comprehensive data set that integrates various characteristic information of crystal particles from the time and space dimensions. The time dimension includes the crystallization velocity characteristics of each time step extracted based on the real-time crystallization velocity of the salt substance, reflecting the change in crystallization velocity; the spatial dimension covers the real-time position characteristics determined by the real-time distribution morphology of the crystal particles (such as the center of mass position of all particle groups and distribution range), real-time shape characteristics, and real-time orientation characteristics obtained by determining the main axis direction through principal component analysis. These characteristics are arranged in sequence to form a matrix, which comprehensively records the dynamic information of the crystal particles during the evaporation and crystallization process, providing a data foundation for subsequent simulation, prediction, and optimization.

[0146] By using the real-time distribution morphology data of crystal particles monitored in real time, and with the help of physical models and computer simulation technology, the aggregation behavior of crystal particles in solution is simulated to understand their mutual approach, binding and movement trajectory, and the state of the solution reaching critical supersaturation is predicted based on the simulation results and crystallization physical and chemical theory.

[0147] Critical supersaturation is a key parameter for crystallization. When the solution reaches this state, crystals begin to form in large quantities. Accurate prediction helps to grasp the crystallization node, adjust the evaporation crystallization parameters, achieve precise control, and improve the efficiency and quality of salt recovery. The aggregation behavior of all crystal particles in the solution refers to the dynamic process in which the crystal particles in the solution are affected by intermolecular forces, surface tension, etc., interact, approach, and combine to form larger aggregates. This process has an important impact on crystallization and the final crystal morphology, size, purity, etc. For example, the arrangement of crystal particles during aggregation affects the growth direction and speed, which in turn affects the quality of recovered salts. Studying it helps to understand the crystallization mechanism and optimize the evaporation crystallization process. Critical supersaturation is an important concept in the solution crystallization process. When the solution is saturated, the solute has a tendency to crystallize, but usually it needs to exceed a certain saturation, that is, the critical supersaturation, before crystals spontaneously form in large quantities. It is the turning point from the stable state to the rapid growth state of crystals, which is affected by multiple factors such as solute type, temperature, and impurity content. In this embodiment, accurately predicting the critical supersaturation is very important for controlling the evaporation crystallization process. When approaching this state, timely adjusting the parameters can promote crystallization under suitable conditions and avoid affecting the quality of salt recovery.

[0148] The dynamic optimization model of evaporation and crystallization parameters is a model built based on multiple data and algorithms. It takes the latest spatiotemporal characteristic matrix of all crystal particles, critical supersaturation and other data as input. Through preset algorithms and rules, it analyzes the difference between the current crystallization state and the ideal state. For example, based on the growth rate and distribution uniformity of the crystal particles and their relationship with the critical supersaturation, it calculates the evaporation and crystallization parameters that need to be adjusted (evaporation temperature, rate, stirring speed, crystallization time, etc.). The model iteratively optimizes based on the latest real-time data and continuously adjusts the parameters to ensure the optimal evaporation and crystallization process, efficiently recover salt substances, and improve product quality.

[0149] The crystal particle state information and predicted critical supersaturation data contained in the latest spatiotemporal characteristic matrix of all crystal particles are input into the dynamic optimization model of evaporation crystallization parameters. The model calculates the current appropriate evaporation crystallization parameter adjustment plan based on this. If the analysis shows that the crystal particles grow slowly and are unevenly distributed, and there is a gap from the critical supersaturation, it may be recommended to increase the evaporation temperature and speed up the stirring speed. The evaporation crystallization equipment parameters are dynamically adjusted according to the model plan. The crystal particle state and salt crystallization situation are continuously monitored during the process, and the new data is fed back to the model for a new round of adjustments. This cycle continues until no salt crystals are precipitated in the wastewater and the recovered salt substances are obtained, thus achieving precise control of the evaporation crystallization process and efficient salt recovery.

[0150] Example 7

[0151] On the basis of Example 6, the latest spatiotemporal feature matrix of all crystal particles is generated based on the real-time crystallization rate of the salt substance and the real-time distribution morphology of all crystal particles, including:

[0152] Extract the crystallization rate characteristics of each time step based on the real-time crystallization rate of salt substances;

[0153] Determine all particle groups based on the real-time distribution morphology of all crystal particles, determine the real-time centroid position and real-time distribution range of all particle groups as the real-time position features of all crystal particles, and extract the real-time shape features of all crystal particles;

[0154] Based on the principal component analysis method and the real-time distribution morphology of all crystal particles, the principal axis directions of all crystal particles are determined as the real-time orientation characteristics of all crystal particles;

[0155] The latest spatiotemporal feature matrix of all crystal particles is generated based on the crystallization velocity characteristics of all time steps currently acquired, the real-time position characteristics, real-time shape characteristics, and real-time orientation characteristics of all crystal particles.

[0156] In this embodiment, extracting the crystallization rate characteristics for each time step based on the real-time crystallization rate of the salt substance means taking a fixed time interval as a time step when observing the evaporation and crystallization process of the salt substance. For each time step, information that reflects the characteristics of the crystallization rate changes during that period is extracted from the real-time crystallization rate data, such as the average crystallization rate, which reflects the average rate of salt crystallization during this time step; or the rate of change of the crystallization rate, which is used to show the change in the crystallization rate in this time step compared to the previous time step. This extracted information constitutes the crystallization rate characteristics for each time step, which helps to analyze the dynamic changes in the crystallization rate over time.

[0157] Determining all particle groups based on the real-time distribution of all crystal particles analyzes the distribution of crystallizing salt crystal particles in a solution. Because the distribution of crystal particles in a solution is not completely uniform, there are relatively concentrated areas, and the crystal particles in these areas can be considered a single particle group. By observing and analyzing the real-time distribution morphology, the crystal particles in the entire solution are divided into different particle groups based on factors such as the spatial position relationship between the crystal particles and the similarity of their motion states, allowing for further study of the behavioral characteristics of the crystal particles in different local areas.

[0158] Determine the real-time center of mass position and real-time distribution range of all particle groups, and calculate the center of mass position for each divided particle group. The center of mass is the average position of the particle group in space, which is obtained by calculating the weighted average of the positions of all crystal particles in the particle group. It can reflect the approximate position of the particle group in the solution. At the same time, determine the distribution range of the particle group in the solution. For example, with the center of mass as the center, measure the distance of the crystal particle farthest from the center of mass in the particle group to define the extension range of the particle group in all directions. The two parameters of real-time center of mass position and real-time distribution range can help understand the real-time spatial state of each particle group in the solution, and provide important information for analyzing behaviors such as aggregation and diffusion of crystal particles.

[0159] Extracting the real-time shape features of all crystal particles involves observing and analyzing the external form of each crystal particle to obtain information describing its shape characteristics. Common shape features include circularity, which measures the degree of closeness of the crystal particle's shape to a circle; aspect ratio, which reflects the ratio of the crystal particle's dimensions in two principal directions; and other shape parameters, such as surface roughness, which describe the crystal particle's shape from different perspectives. By extracting these real-time shape features, we can understand the changes in the growth morphology of crystal particles during the crystallization process and the characteristics of crystal growth under different conditions. This is of great significance for understanding the crystallization mechanism and optimizing the evaporation crystallization process.

[0160] The main axis direction of all crystal particles is determined based on the real-time distribution form of principal component analysis and all crystal particles. Principal component analysis is a data dimension reduction method, which can extract the most important information from complex data. In this embodiment, in conjunction with the real-time distribution form data of all crystal particles, the direction that can explain the data variance to the greatest extent is found by principal component analysis, and this direction is the main axis direction of all crystal particles. The main axis direction of crystal particles reflects their arrangement trend on the whole, which is important for understanding the aggregation and growth mode of crystal particles in solution. For example, the main axis direction may be associated with some physical fields (such as electric field, flow field etc.) in the solution, affecting the growth direction and final form of the crystal.

[0161] Based on the crystallization velocity characteristics of all time steps currently acquired, the real-time position characteristics, real-time shape characteristics, and real-time orientation characteristics of all crystal particles, the latest spatiotemporal feature matrix of all crystal particles is generated. The crystallization velocity characteristics collected at different time steps during the evaporation crystallization process, as well as the real-time position characteristics (center of mass position and distribution range), real-time shape characteristics (circularity, aspect ratio, etc.), and real-time orientation characteristics (main axis direction) of all crystal particles at the corresponding moment are integrated. A matrix is constructed with time steps as rows and different types of features as columns. This matrix comprehensively records the spatiotemporal variation information of crystal particles during the evaporation crystallization process, displays the dynamic changes of crystallization velocity from the time dimension, and presents the position, shape, and orientation characteristics of crystal particles from the spatial dimension. It provides a rich data foundation for further analyzing the behavior of crystal particles, predicting the crystallization process, and optimizing evaporation crystallization parameters.

[0162] Example 8

[0163] Based on Example 1, S4: mixing the pretreated aluminum ash, water, and additives in a reactor according to a preset ratio to produce a hydrolysis reaction, and constructing a digital twin model of the aluminum ash hydrolysis reaction. At the same time, ammonia generated by the hydrolysis reaction is collected based on a water absorption device until the hydrolysis reaction no longer progresses, thereby obtaining recovered ammonia and hydrolysis products, including:

[0164] The pretreated aluminum ash, water and additives are mixed in a reactor according to a preset ratio to produce a hydrolysis reaction;

[0165] At the same time, the ammonia produced by the hydrolysis reaction is collected based on the water absorption device;

[0166] At the same time, a digital twin model of the aluminum ash hydrolysis reaction is constructed based on the basic reaction parameters and reaction process parameters in the reactor, and the basic reaction parameters in the reactor are optimized and adjusted based on the digital twin model of the aluminum ash hydrolysis reaction until the hydrolysis reaction no longer produces progress, and the recovered ammonia and hydrolysis products are obtained.

[0167] In this embodiment, the pretreated aluminum ash, water, and additive are mixed in a reactor according to a preset ratio to produce a hydrolysis reaction, which means that the ratio of the three substances mixed with each other is determined in advance based on the chemical principle of aluminum ash hydrolysis and the actual processing requirements. Afterwards, the pretreated aluminum ash, an appropriate amount of water, and a specific additive are put into the reactor according to a predetermined ratio. Under the suitable environment (such as specific temperature and pressure conditions) provided by the reactor, a hydrolysis reaction will occur between them, prompting certain components in the aluminum ash to react chemically with water under the action of the additive, generating hydrolyzate and releasing ammonia. This is a key step in the aluminum ash treatment process, which lays the foundation for subsequent recovery of ammonia and further processing of the hydrolyzate.

[0168] The basic reaction parameters in a reactor include temperature, pressure, and reactant concentration. Temperature affects the reaction rate and direction. Different aluminum ash hydrolysis reactions may require a specific temperature range to ensure efficient reaction. Pressure also affects the reaction; appropriate pressure helps maintain reaction stability. Reactant concentration determines the amount of reactants involved, directly affecting the reaction progress and product yield.

[0169] Reaction process parameters include reaction time, product yield, and other data. Reaction time records the duration of the reaction from its inception to its various stages, while product yield provides a visual representation of the success of each stage. Together, these parameters reflect the real-time status of the aluminum ash hydrolysis reaction in the reactor.

[0170] Building a digital twin model of the aluminum ash hydrolysis reaction based on the basic reaction parameters and reaction process parameters in the reactor utilizes collected data such as temperature, pressure, reactant concentration, reaction time, and product yields, using computer simulation and related algorithms to create a virtual model corresponding to the actual aluminum ash hydrolysis reaction. This model can simulate the dynamic changes in various parameters during the actual reaction process and the interactions between them. For example, based on the input of the initial basic reaction parameters, the model can simulate how the product yield changes over reaction time, and how changes in temperature and pressure affect this process, providing a powerful tool for in-depth understanding and optimization of the reaction.

[0171] Optimizing and adjusting the basic reaction parameters in the reactor based on the digital twin model of the aluminum ash hydrolysis reaction means using the digital twin model's simulation and analysis capabilities for the reaction process to identify problems or areas for optimization under the current basic reaction parameter settings. For example, if the model simulation shows that the product generation rate is slow or the generation amount does not meet expectations under the current temperature and reactant concentration, then the basic reaction parameters such as temperature, pressure, or reactant concentration in the reactor can be adjusted in a targeted manner based on the model analysis results. By continuously re-entering the adjusted parameters into the model for simulation verification and repeated optimization, the basic reaction parameters in the reactor are optimized, thereby improving the efficiency of the aluminum ash hydrolysis reaction and the quality of the products, and achieving precise control and optimization of the aluminum ash hydrolysis reaction process.

[0172] Example 9

[0173] Based on Example 1, S5: acid leaching the hydrolyzate to obtain a recovered valuable metal salt solution and a final residue, and performing harmless treatment on the final residue to obtain a harmless residue, comprising:

[0174] Conduct composition analysis and structural characterization on the hydrolysis products to determine the occurrence state of valuable metals;

[0175] Determining acid leaching process parameters based on the occurrence state of the valuable metals, and acid leaching the hydrolyzed product based on the acid leaching process parameters to obtain a recovered valuable metal salt solution and a final residue;

[0176] The solidification process of the final residue is adjusted based on an adaptive control algorithm until the residue reaches the harmlessness standard to obtain harmless residue.

[0177] In this embodiment, the compositional analysis and structural characterization of the hydrolyzate to determine the occurrence state of the valuable metals utilizes a variety of analytical techniques, such as X-ray diffraction (XRD) to determine the crystal structure and phases of the hydrolyzate, thereby understanding the types of compounds in which the valuable metals are present; scanning electron microscopy (SEM) to observe the microscopic morphology and clarify the distribution of the valuable metals in the hydrolyzate; and chemical analysis to determine the content of each element and accurately determine the proportion of the valuable metals. Through these analyses, the occurrence state of the valuable metals, such as the compound form in which the valuable metals exist and their location in the microstructure of the hydrolyzate, is fully determined, providing key information for subsequent extraction of the valuable metals.

[0178] The acid leaching process parameters are determined based on the occurrence state of the valuable metals because different occurrence states require different acid leaching conditions to effectively extract the valuable metals. If the valuable metals exist in the form of less soluble compounds, it may be necessary to select a more acidic and higher concentration acid as the leaching agent, while appropriately increasing the acid leaching temperature and extending the acid leaching time. If the occurrence form is relatively easy to react with acid, milder acid leaching conditions can be used. In addition, parameters such as stirring speed must also be considered to ensure sufficient contact and reaction between the acid and the hydrolysis product, ensuring efficient extraction of the valuable metals while avoiding the increased costs and adverse effects of excessive reaction on subsequent processing.

[0179] Acid leaching of the hydrolyzate based on the acid leaching process parameters produces a recovered valuable metal salt solution and a final residue. This involves placing the hydrolyzate in an acid leaching environment with pre-defined parameters for reaction. Based on the selected acid leaching agent type and concentration, and under defined conditions such as temperature, time, and stirring speed, the acid reacts chemically with the valuable metals in the hydrolyzate, dissolving them into solution and forming a recovered valuable metal salt solution. The portion of the hydrolyzate that does not react with the acid remains as the final residue, achieving a preliminary separation of the valuable metals from other impurities and paving the way for subsequent purification of the valuable metals and residue treatment.

[0180] The curing process of the final residue is adjusted based on an adaptive control algorithm until the residue reaches the harmless standard and a harmless residue is obtained. The adaptive control algorithm is used to automatically adjust the relevant parameters of the curing process according to the current characteristics of the final residue (such as composition, stability, etc.). The algorithm monitors the status of the residue in real time and compares it with the harmless standard. If it is found that the content of certain harmful substances in the residue exceeds the standard or the stability does not meet the requirements, the type and amount of the curing agent, as well as the curing temperature, time and other parameters will be automatically changed. By continuously adjusting these parameters, the final residue is cured so that the harmful substances in the residue are fixed or converted into a harmless form. Continuous optimization is carried out until the residue meets the harmless standard, thereby obtaining a harmless residue that does not pollute the environment.

[0181] In this embodiment, the harmlessness standard refers to a series of specifications and requirements set for the final residue, used to determine whether the residue poses no risk to the environment or human health. These standards cover a variety of aspects, such as restrictions on the heavy metal content in the residue, stipulating that the leaching concentration of heavy metals such as lead, mercury, and cadmium must be below a specific value to prevent them from entering the soil, water, and other environmental pollutants; requirements for residue stability to ensure that the residue does not easily decompose or release harmful substances under natural environmental conditions; and restrictions on other physical and chemical properties of the residue, such as pH, to ensure that it meets environmental safety indicators. Only residues that meet these standards are considered harmless and can be safely disposed of or reused.

[0182] Example 10

[0183] Based on Examples 1 to 9, a system for a harmless and resource-based comprehensive treatment method for aluminum ash is provided. Figure 2 ,include:

[0184] The aluminum ash screening end is used to set the screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing process parameters, and control the screening equipment based on the screening parameters to remove large particles of impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash;

[0185] The aluminum ash washing end is used to determine the control parameters of the water washing equipment based on the content of water-soluble salts in the screened aluminum ash and the correlation model between the aluminum ash characteristics and the treatment process parameters, and control the water washing equipment to wash the screened aluminum ash based on the corresponding control parameters to obtain wastewater containing water-soluble salts and pre-treated aluminum ash;

[0186] The salt evaporation and crystallization end is used to evaporate and crystallize wastewater containing water-soluble salts. At the same time, the evaporation and crystallization parameters are dynamically adjusted until the wastewater no longer crystallizes salt substances, and the salt substances are recovered;

[0187] The hydrolysis reaction execution monitoring terminal is used to mix the pretreated aluminum ash, water, and additives in a reactor according to a preset ratio to produce a hydrolysis reaction, and to build a digital twin model of the aluminum ash hydrolysis reaction. At the same time, a water absorption device is used to collect ammonia produced by the hydrolysis reaction until the hydrolysis reaction stops, and then the ammonia and hydrolysis products are recovered;

[0188] The acid leaching, impurity removal and harmless treatment end is used to acid-leach and remove impurities from the hydrolyzate to obtain recovered valuable metal salts and final residue, and to perform harmless treatment on the final residue to obtain harmless residue.

[0189] This comprehensive treatment method for harmless resource utilization of aluminum ash sets screening parameters based on the physical characteristics of the aluminum ash to be treated and the correlation model between the aluminum ash characteristics and the treatment process parameters, removes large-particle impurities and metal aluminum blocks, and accurately pre-treats to improve the efficiency of subsequent treatment and product purity. The control parameters of the water washing equipment are determined by the water-soluble salt content of the aluminum ash after pre-treatment and the correlation model. The water-soluble salts are separated by water washing. The wastewater is evaporated and crystallized, and the parameters are dynamically adjusted to maximize the recovery of salt substances and reduce salt residue in the wastewater. The pre-treated aluminum ash, water, and additives are mixed in a preset ratio for hydrolysis reaction. A digital twin model is constructed to monitor the optimization process in real time. Ammonia is recovered by water absorption device to improve resource utilization. The hydrolysis product is acid leached to obtain a valuable metal salt solution. The residue is finally harmlessly treated to obtain a harmless residue, completing the complete process from resource recovery and harmless treatment of aluminum ash, in line with the concepts of green environmental protection and sustainable development.

[0190] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the present invention and its equivalents, the present invention is intended to include these modifications and variations.

Claims

1. A method for comprehensive treatment of harmless aluminum ash resources, characterized in that: include: S1: Setting screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing parameters, and controlling the screening equipment based on the screening parameters to remove large particles of impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash; S2: Determine control parameters of a water washing device based on the content of water-soluble salts in the screened aluminum ash and a correlation model between aluminum ash characteristics and treatment process parameters, and control the water washing device to wash the screened aluminum ash based on the corresponding control parameters to obtain wastewater containing water-soluble salts and pretreated aluminum ash; S3: Evaporating and crystallizing the wastewater containing water-soluble salts, while dynamically adjusting the evaporation and crystallization parameters until the wastewater no longer crystallizes salts, thereby recovering the salts; S4: The pretreated aluminum ash, water, and additives are mixed in a reactor according to a preset ratio to produce a hydrolysis reaction, and a digital twin model of the aluminum ash hydrolysis reaction is constructed. At the same time, ammonia generated by the hydrolysis reaction is collected using a water absorption device until the hydrolysis reaction no longer progresses, and the recovered ammonia and hydrolysis products are obtained; S5: acid leaching the hydrolyzed product to obtain a recovered valuable metal salt solution and a final residue, and performing harmless treatment on the final residue to obtain a harmless residue.

2. The method for harmless and resource-based comprehensive treatment of aluminum ash according to claim 1, characterized in that: S1: Setting the screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing parameters, and controlling the screening equipment based on the screening parameters to remove large particles of impurities and metal aluminum blocks in the aluminum ash to be processed to obtain the screened aluminum ash, including: Obtaining the physical characteristics of the aluminum ash to be processed; Establish a correlation model between aluminum ash characteristics and treatment process parameters; The aperture and vibration frequency of the screening equipment are set as screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing parameters; Based on the screening parameters, the screening equipment is controlled to remove large particle impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash.

3. The method for harmless and resource-based comprehensive treatment of aluminum ash according to claim 1, characterized in that: S2: Determine the control parameters of the water washing equipment based on the content of water-soluble salts in the screened aluminum ash and the correlation model between the aluminum ash characteristics and the treatment process parameters, and control the water washing equipment to wash the screened aluminum ash based on the corresponding control parameters to obtain wastewater containing water-soluble salts and pretreated aluminum ash, including: Obtaining the chemical composition of the sieved aluminum ash; Determining the content of water-soluble salts in the screened aluminum ash based on the chemical composition of the screened aluminum ash, and determining control parameters of the water washing equipment based on the content of water-soluble salts in the screened aluminum ash and a correlation model; Based on the corresponding control parameters, the water washing equipment is controlled to wash the screened aluminum ash with water to obtain wastewater containing water-soluble salts and pretreated aluminum ash.

4. The method for harmless and resource-based comprehensive treatment of aluminum ash according to claim 1, characterized in that: S3: Evaporating and crystallizing the wastewater containing water-soluble salts, and dynamically adjusting the evaporation and crystallization parameters until the wastewater no longer crystallizes salt substances, thereby recovering the salt substances, including: Evaporation and crystallization of wastewater containing water-soluble salts, while monitoring the real-time crystallization rate of salt substances and the real-time distribution morphology of all crystal particles; The evaporation crystallization parameters are dynamically adjusted based on the real-time crystallization speed of the salt substance and the real-time distribution morphology of all crystal particles until the wastewater no longer crystallizes salt substances, and the recovered salt substances are obtained.

5. The method for harmless and resource-based comprehensive treatment of aluminum ash according to claim 4 is characterized in that: Monitor the real-time crystallization rate of salt substances and the real-time distribution morphology of all crystal particles, including: Obtain real-time evaporation and crystallization monitoring video of wastewater, and analyze the real-time number, real-time particle size, and real-time distribution of all crystal particles in the wastewater based on an image segmentation algorithm, and analyze the first real-time crystallization speed of the salt substance based on the real-time number and real-time particle size of all crystal particles; Analyze the second real-time crystallization rate of salt substances based on laser scattering method; Analyze the third real-time crystallization rate of salt substances based on density monitoring method; Analyze the fourth real-time crystallization rate of salt substances based on the conductivity monitoring method; determining a crystallization stage of the salt substance based on a first real-time crystallization rate, a second real-time crystallization rate, a third real-time crystallization rate, a fourth real-time crystallization rate, and a real-time distribution morphology of the salt substance; The current contribution of each monitoring means is determined based on the crystallization stage of the salt substance, and the real-time crystallization rate of the salt substance is determined based on the first real-time crystallization rate, the second real-time crystallization rate, the third real-time crystallization rate, the fourth crystallization rate and the current contribution of each monitoring means.

6. The method for harmless and resourceful comprehensive treatment of aluminum ash according to claim 4 is characterized in that: Based on the real-time crystallization rate of the salt substances and the real-time distribution morphology of all crystal particles, the evaporation crystallization parameters are dynamically adjusted until the wastewater no longer crystallizes salt substances, and the recovered salt substances are obtained, including: Generate the latest spatiotemporal characteristic matrix of all crystal particles based on the real-time crystallization speed of salt substances and the real-time distribution morphology of all crystal particles; Simulate the aggregation behavior of all crystal particles in solution based on their real-time distribution morphology and predict the critical supersaturation; Based on the latest spatiotemporal characteristic matrix of all crystal particles, critical supersaturation and dynamic optimization model of evaporation crystallization parameters, the evaporation crystallization parameters are dynamically adjusted until the wastewater no longer crystallizes salt substances, and the recovered salt substances are obtained.

7. The method for harmless and resourceful comprehensive treatment of aluminum ash according to claim 6, characterized in that: Based on the real-time crystallization rate of salt substances and the real-time distribution morphology of all crystal particles, the latest spatiotemporal feature matrix of all crystal particles is generated, including: Extract the crystallization rate characteristics of each time step based on the real-time crystallization rate of salt substances; Determine all particle groups based on the real-time distribution morphology of all crystal particles, determine the real-time centroid position and real-time distribution range of all particle groups as the real-time position features of all crystal particles, and extract the real-time shape features of all crystal particles; Based on the principal component analysis method and the real-time distribution morphology of all crystal particles, the principal axis directions of all crystal particles are determined as the real-time orientation characteristics of all crystal particles; The latest spatiotemporal feature matrix of all crystal particles is generated based on the crystallization velocity characteristics of all time steps currently acquired, the real-time position characteristics, real-time shape characteristics, and real-time orientation characteristics of all crystal particles.

8. The method for harmless and resourceful comprehensive treatment of aluminum ash according to claim 1, characterized in that: S4: Mixing the pretreated aluminum ash, water, and additives in a reactor according to a preset ratio to produce a hydrolysis reaction, and constructing a digital twin model of the aluminum ash hydrolysis reaction. At the same time, ammonia generated by the hydrolysis reaction is collected using a water absorption device until the hydrolysis reaction no longer progresses, thereby obtaining recovered ammonia and hydrolysis products, including: The pretreated aluminum ash, water and additives are mixed in a reactor according to a preset ratio to produce a hydrolysis reaction; At the same time, the ammonia produced by the hydrolysis reaction is collected based on the water absorption device; At the same time, a digital twin model of the aluminum ash hydrolysis reaction is constructed based on the basic reaction parameters and reaction process parameters in the reactor, and the basic reaction parameters in the reactor are optimized and adjusted based on the digital twin model of the aluminum ash hydrolysis reaction until the hydrolysis reaction no longer produces progress, and the recovered ammonia and hydrolysis products are obtained.

9. The method for harmless and resourceful comprehensive treatment of aluminum ash according to claim 1, characterized in that: S5: acid leaching the hydrolyzed product to obtain a recovered valuable metal salt solution and a final residue, and performing harmless treatment on the final residue to obtain a harmless residue, including: Conduct composition analysis and structural characterization on the hydrolysis products to determine the occurrence state of valuable metals; Determining acid leaching process parameters based on the occurrence state of the valuable metals, and acid leaching the hydrolyzed product based on the acid leaching process parameters to obtain a recovered valuable metal salt solution and a final residue; The solidification process of the final residue is adjusted based on an adaptive control algorithm until the residue reaches the harmlessness standard to obtain harmless residue.

10. The system of the method for comprehensive harmless resource recovery of aluminum ash according to any one of claims 1 to 9, characterized in that: include: The aluminum ash screening end is used to set the screening parameters of the screening equipment based on the physical characteristics of the aluminum ash to be processed and the correlation model between the aluminum ash characteristics and the processing process parameters, and control the screening equipment based on the screening parameters to remove large particles of impurities and metal aluminum blocks in the aluminum ash to be processed to obtain screened aluminum ash; The aluminum ash washing end is used to determine the control parameters of the water washing equipment based on the content of water-soluble salts in the screened aluminum ash and the correlation model between the aluminum ash characteristics and the treatment process parameters, and control the water washing equipment to wash the screened aluminum ash based on the corresponding control parameters to obtain wastewater containing water-soluble salts and pre-treated aluminum ash; The salt evaporation and crystallization end is used to evaporate and crystallize wastewater containing water-soluble salts. At the same time, the evaporation and crystallization parameters are dynamically adjusted until the wastewater no longer crystallizes salt substances, and the salt substances are recovered; The hydrolysis reaction execution monitoring terminal is used to mix the pretreated aluminum ash, water, and additives in a reactor according to a preset ratio to produce a hydrolysis reaction, and to build a digital twin model of the aluminum ash hydrolysis reaction. At the same time, a water absorption device is used to collect ammonia produced by the hydrolysis reaction until the hydrolysis reaction stops, and then the ammonia and hydrolysis products are recovered; The acid leaching, impurity removal and harmless treatment end is used to acid-leach and remove impurities from the hydrolyzate to obtain recovered valuable metal salts and final residue, and to perform harmless treatment on the final residue to obtain harmless residue.

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