Fly ash slag salt separation, conditioning and purification method and system

Abstract

The invention discloses a fly ash salt separation, conditioning and purification method and system. According to the fly ash slag salt separation, tempering and purification method, after slag / salt separation is achieved in the fly ash melting process (not to promote volatilization of molten salt), the molten slag and the molten salt are subjected to tempering, impurity removal and homogenization through independent equipment. The molten slag and the molten salt which are subjected to tempering, impurity removal and homogenization meet the basic requirement of next-step resource utilization, complete resource utilization of the waste incineration fly ash can be achieved, and the requirement of zero landfill is met. According to the fly ash slag and salt separating, tempering and purifying system, the slag and salt separating furnace, the tempering and homogenizing furnace and the molten salt electrolysis furnace are organically connected, stable and continuous molten slag discharging and molten salt discharging are achieved, the molten slag and the molten salt are tempered, clarified and homogenized in the corresponding devices respectively, target molten slag and target molten salt are obtained, and the quality of the fly ash slag and the quality of the molten salt are improved. And a foundation is laid for later resource utilization.

Description

Technical Field

[0001] This invention relates to the field of waste incineration fly ash treatment technology, and in particular to a method and system for separating, conditioning and purifying fly ash residue salt. Background Technology

[0002] Currently, the technology for melting and treating fly ash from waste incineration faces challenges such as complex processes, high energy consumption, low resource utilization, poor product quality, and immature slag / molten salt separation technology.

[0003] In related technologies, granulation is commonly used, requiring powdered fly ash to be granulated before being fed into melting equipment. This process adds extra steps, resulting in high equipment investment, complex operation, and the potential introduction of impurities during granulation, affecting subsequent resource recovery. Furthermore, some technologies promote chloride volatilization through high-temperature melting, achieving salt capture, but this requires maintaining temperatures above 1300℃ and extending the melting time to ensure complete chloride volatilization, leading to significantly increased energy consumption and low melting efficiency.

[0004] In related technologies, most focus is on the resource utilization of molten slag, while research on the further utilization of molten salt is insufficient. For example, although some technologies propose molten slag resource utilization schemes, they do not involve the separation and purification of molten salt; although flue gas purification and sludge return to the furnace are mentioned, there is process redundancy and the quality of resource-utilized products is unstable. In addition, some technologies use water washing pretreatment, which can reduce the salt content in fly ash, but it consumes a large amount of water resources, and the fly ash needs to be dried after water washing, further increasing costs.

[0005] Among the related technologies, only a few solutions propose slag / molten salt separation, but none of them address the conditioning, homogenization, and resource utilization processes for the separated slag and molten salt. For example, there is the molten vitrification technology, but the separation mechanism between slag and molten salt is not clearly defined, resulting in residual salt in the slag, which affects its performance as a building material raw material; some technologies treat calcium sulfate through carbothermic reduction, but do not solve the problem of efficient separation of chloride salts. Summary of the Invention

[0006] The present invention aims to at least partially solve one of the technical problems in the related art.

[0007] Therefore, embodiments of the present invention propose a method for separating, conditioning, and purifying fly ash residue salt, which simplifies the process flow, reduces energy consumption and costs, improves resource utilization efficiency, and achieves the goal of zero landfill.

[0008] Embodiments of the present invention also propose a fly ash slag salt separation, conditioning and purification system.

[0009] The fly ash residue salt separation, conditioning and purification method of this invention includes: Dehydrated fly ash and auxiliary materials are transported into the slag-salt separation furnace according to a preset ratio; The slag-salt separation furnace is heated by electrodes and uses the density difference between molten slag and molten salt to separate the two high-temperature melts in the furnace into two layers. The upper layer is the molten salt layer, which is discharged through the salt discharge port of the slag-salt separation furnace. The lower layer is the molten slag layer, which flows through the arch in the slag-salt separation furnace to the slag discharge port. The molten slag discharged from the slag-salt separation furnace is fed into the conditioning and homogenizing furnace through the molten slag chute. The cold material is fed into the furnace through the feeding port of the conditioning and homogenizing furnace. The conditioning and homogenizing furnace heats the material through electrodes. After the material is conditioned, clarified and homogenized in the conditioning and homogenizing furnace, a target molten slag with a single composition is obtained. The target molten slag flows from the arch in the conditioning and homogenizing furnace to the slag discharge port and is discharged. The molten salt discharged from the slag-salt separation furnace is fed into the molten salt electrolysis furnace through the molten salt chute. After the molten salt passes through the electrode plates of the molten salt electrolysis furnace to remove impurity elements, the target molten salt is obtained. The target molten salt flows from the arch in the molten salt electrolysis furnace to the salt discharge port and is discharged.

[0010] The fly ash / salt separation, conditioning, and purification method of this invention achieves slag / salt separation during fly ash melting (not by promoting the volatilization of molten salt). The molten slag and molten salt are then conditioned, impurity removed, and homogenized using separate equipment. The conditioned, impurity removed, and homogenized molten slag and molten salt meet the basic requirements for subsequent resource utilization, enabling complete resource utilization of waste incineration fly ash and achieving the "zero landfill" requirement.

[0011] In some embodiments, waste incineration fly ash is dehydrated using steam to reduce the moisture content of the fly ash fed into the slag-salt separator to ≤1%.

[0012] In some embodiments, fly ash is the main material, with a mass fraction of 50-100%. The auxiliary materials include a first-class flux with a mass fraction of 0-50% and a second-class flux with a mass fraction of 0-20%. The first-class flux includes NaCl, CaCl2, NaCl+CaCl2, or solid waste containing chloride salts, such as hazardous waste incineration fly ash or waste salt. The second-class flux includes quartz sand (SiO2) or siliceous solid waste.

[0013] In some embodiments, the temperature in the slag-salt separation furnace is controlled at 8000–1350°C, the temperature in the conditioning and homogenizing furnace is controlled at 1400–1600°C, and the temperature in the molten salt electrolysis furnace is controlled at 700–1000°C.

[0014] In some embodiments, the density of molten slag in the slag-salt separation furnace is 2.6–3.0 t / m³, and the density of molten salt in the slag-salt separation furnace is 1.8–2.0 t / m³.

[0015] The fly ash residue salt separation, conditioning and purification system of this invention includes: A slag-salt separation furnace is provided with a slag discharge port and a salt discharge port, wherein the slag discharge port is located at the lower part of the slag-salt separation furnace and the salt discharge port is located at the upper part of the slag-salt separation furnace; A quenching and homogenizing furnace is provided with a slag inlet and a quenching and homogenizing slag outlet. The slag inlet is connected to the slag outlet through a slag chute. The quenching and homogenizing slag outlet is used to discharge the target slag after quenching, clarifying and homogenizing in the quenching and homogenizing furnace. A molten salt electrolysis furnace is provided with a molten salt inlet and a purified salt outlet. The molten salt inlet is connected to the purified salt outlet through a molten salt chute. The purified salt outlet is used to discharge the target molten salt after electrolytic purification in the molten salt electrolysis furnace.

[0016] In some embodiments, the slag-salt separation furnace, the conditioning and homogenizing furnace, and the molten salt electrolysis furnace are all equipped with partition walls, which divide the chambers inside the furnace into two, and an arched opening is provided below the partition wall to connect the two chambers.

[0017] In some embodiments, the slag chute is equipped with a heat preservation device and a fuel combustion gun is provided inside the slag chute to keep the temperature of the slag inside the slag chute above the solidification temperature.

[0018] In some embodiments, electrodes are provided in both the slag-salt separation furnace and the conditioning and homogenizing furnace, and the electrodes are used to heat the furnace. The molten salt electrolysis furnace is provided with electrode plates, and the electrode plates include one or more sets of anode-cathode pairs.

[0019] In some embodiments, the slag-salt separation furnace, the conditioning and homogenizing furnace, and the molten salt electrolysis furnace are all equipped with flues. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the fly ash residue salt separation, conditioning and purification system according to an embodiment of the present invention.

[0021] Figure label: 1-Slag-salt separation furnace, 101-Slag discharge port, 102-Salt discharge port, 103-First partition wall, 104-First arch, 105-First electrode, 106-First flue, 107-First feed port 2-Quenching and homogenizing furnace, 201-Slag inlet, 202-Quenching and slag outlet, 203-Second partition wall, 204-Second arch, 205-Second electrode, 206-Second flue, 207-Second charging port, 3-Molten salt electrolysis furnace, 301-Molten salt inlet, 302-Purified salt outlet, 303-Third partition wall, 304-Third arch, 305-Electrode plate, 306-Third flue. 4-Slag chute, 5-Molten salt chute. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] The following is in conjunction with the appendix Figure 1 This invention describes a method for separating, conditioning, and purifying fly ash residue salt according to an embodiment of the present invention.

[0024] The fly ash residue salt separation, conditioning and purification method of this invention includes: Dehydrated fly ash and auxiliary materials are fed into the slag-salt separator 1 according to a preset ratio. Compared to the "granulation process" in related technologies, which increases the process flow and complexity, this embodiment of the invention uses powdered fly ash directly fed into the furnace.

[0025] The slag-salt separation furnace 1 is heated by electrodes and utilizes the density difference between molten slag and molten salt to separate the two high-temperature melts into layers. The upper layer in the furnace is the molten salt layer, which is discharged through the salt discharge port 102 of the slag-salt separation furnace 1. The lower layer in the furnace is the molten slag layer, which flows through the arched passage in the slag-salt separation furnace 1 to the slag discharge port 101 and is discharged.

[0026] In contrast to related technologies where "at higher melting temperatures, molten salt is volatilized and captured in the flue gas purification system as dust, requiring extended melting time to ensure complete volatilization, significantly reducing the efficiency of fly ash melting and disposal," this invention achieves preliminary slag-salt separation during fly ash melting (not by promoting molten salt volatilization), also known as primary slag-salt separation. The separated slag and molten salt are then subjected to conditioning, impurity removal, and homogenization using separate equipment.

[0027] The molten slag discharged from the slag-salt separation furnace 1 is fed into the quenching and homogenizing furnace 2 through the molten slag chute 4. The cold material is fed into the furnace through the feeding port of the quenching and homogenizing furnace 2. The quenching and homogenizing furnace 2 heats the material through electrodes. After the material is quenched, clarified and homogenized in the quenching and homogenizing furnace 2, a target molten slag with a single composition is obtained. The target molten slag flows from the arch in the quenching and homogenizing furnace 2 to the slag discharge port 101 and is discharged.

[0028] The molten salt discharged from the slag-salt separation furnace 1 is fed into the molten salt electrolysis furnace 3 through the molten salt chute 5. After the molten salt passes through the electrode plate 305 of the molten salt electrolysis furnace 3 to remove impurity elements, the target molten salt is obtained. The target molten salt flows from the arch in the molten salt electrolysis furnace 3 to the salt discharge port 102 for discharge.

[0029] The separated slag and molten salt are selectively subjected to fine slag-salt separation (also known as secondary slag-salt separation) based on the impurity content. The purpose is to further remove molten salt from the slag system and further remove slag from the molten salt system, so as to meet the requirements of separate resource utilization processes for slag and molten salt, and direct energy utilization of hot slag and hot molten salt.

[0030] The fly ash / salt separation, conditioning, and purification method of this invention achieves slag / salt separation during fly ash melting (not by promoting molten salt volatilization). The molten slag and molten salt are then conditioned, impurity removed, and homogenized using separate equipment. The conditioned, impurity removed, and homogenized molten slag and molten salt meet the basic requirements for subsequent resource utilization, enabling complete resource utilization of waste incineration fly ash and achieving the "zero landfill" requirement. The entire process is short and efficient, which helps reduce fly ash disposal costs.

[0031] Optionally, the fly ash from waste incineration is dehydrated using steam to reduce the moisture content of the fly ash fed into the slag-salt separator 1 to ≤1%.

[0032] Understandably, if the moisture content of the fly ash is too high, the moisture will vaporize instantly within the slag-salt separator 1, causing violent splashing of the molten material. This will lead to a chaotic interface between the molten slag and molten salt, disrupting density stratification. Therefore, controlling the moisture content of the fly ash entering the furnace to ≤1% ensures the safe operation of the fly ash melting process and improves the effectiveness of slag-salt separation.

[0033] Furthermore, the density of the molten slag in the slag-salt separation furnace 1 is 2.6–3.0 t / m³, and the density of the molten salt in the slag-salt separation furnace 1 is 1.8–2.0 t / m³. That is, the critical density difference between the molten slag and the molten salt is ≥0.8 t / m³, achieving a clear stratification interface.

[0034] Optionally, the temperature inside the slag-salt separation furnace 1 is controlled at 800–1350℃. This temperature ensures the balance between density difference and settling velocity, and is preferably 800–1000℃ (minimum volatilization). The temperature inside the conditioning and homogenizing furnace 2 is controlled at 1400–1600℃. The temperature in the conditioning and homogenizing furnace 2 drives mineral phase transformation and impurity separation. The temperature inside the molten salt electrolysis furnace 3 is controlled at 700–1000℃. The temperature in the molten salt electrolysis furnace 3 balances ion migration and selective precipitation, and is preferably 700–800℃ (minimum corrosivity).

[0035] Optionally, fly ash is the main material, with a mass fraction of 50-100%. Auxiliary materials include a Class I flux with a mass fraction of 0-50% and a Class II flux with a mass fraction of 0-20%. The Class I flux includes NaCl, CaCl2, NaCl+CaCl2, or solid waste containing chloride salts, such as hazardous waste incineration fly ash or waste salts; the Class II flux includes quartz sand (SiO2) or siliceous solid waste.

[0036] The following describes in detail the fly ash residue salt separation, conditioning and purification method of the present invention.

[0037] Example 1: Waste incineration fly ash is dehydrated using steam, reducing the moisture content to 0.5%. The dehydrated powdered fly ash is directly fed into the slag-salt separator 1. Quartz sand is conveyed by a screw conveyor and fed into the slag-salt separator 1 in a certain proportion. The SiO2 / CaO ratio in the molten pool is 1.0.

[0038] The slag-salt separation furnace 1 is heated by electrodes, with an average molten pool temperature of 1250℃. It utilizes the density difference between molten slag and molten salt (molten slag ρ≈2.8t / m³). 3 ) and molten salt (ρ≈1.9t / m 3 The two high-temperature melts in the furnace are separated into layers. The upper layer is the molten salt layer, which is discharged through the salt discharge port 102. The lower layer is the molten slag layer, which flows from the arch to the slag discharge port 101 to obtain molten slag, thus realizing the primary slag-salt separation.

[0039] The slag from the slag discharge port 101 enters the quenching and homogenizing furnace 2 through the slag chute 4. Quartz sand and bauxite are fed into the quenching and homogenizing furnace 2 from the feed port. The materials are heated by electrodes, and the average temperature of the molten pool is 1500℃. After the materials are quenched, clarified and homogenized in the quenching and homogenizing furnace 2, a new slag with a single composition is obtained. It then flows through the arch to the quenching and slag discharge port 202 to obtain the target slag with SiO2 / CaO=1.8.

[0040] Molten salt from the salt outlet 102 enters the molten salt electrolysis furnace 3 through the molten salt chute 5. The average temperature of the molten pool is 950℃. The electrode plate 305 consists of two sets of anode-cathode plates 305. The molten salt removes impurity elements under the electrolysis of the electrode plate 305, and then flows through the arch to the purification salt outlet 302 to obtain the target molten salt.

[0041] The fly ash residue salt separation, conditioning and purification method of the first specific embodiment of the present invention has the following advantages: The process flow is simplified by directly feeding powdered fly ash into the furnace (without the need for granulation), reducing process steps and lowering equipment complexity.

[0042] To reduce energy consumption and costs, the slag and salt are separated by density differences, avoiding high-temperature volatilization. The melting temperature is controlled at 1250℃, significantly shortening the melting time.

[0043] To improve resource utilization efficiency, the separated slag and molten salt are fed into the conditioning and homogenizing furnace 2 and the molten salt electrolysis furnace 3, respectively. Through fine processing (such as SiO2 / CaO ratio control and electrolytic impurity removal), high-purity products are obtained to meet the resource utilization needs of building materials, chemical raw materials and other industries.

[0044] To achieve the goal of zero landfill, a systematic design (such as sealed chute connections and centralized flue gas treatment) is used to ensure the complete resource utilization of salt and slag in fly ash and avoid secondary pollution.

[0045] Example 2: Waste incineration fly ash is dehydrated using steam, reducing the moisture content to 0.7%. The dehydrated powdered fly ash is directly fed into slag-salt separator 1. Glyphosate waste salt (NaCl content of 93.4%) is conveyed by a screw conveyor, and quartz sand is conveyed by a screw conveyor. The three materials are fed into slag-salt separator 1 in a mass fraction of 50:30:20. The SiO2 / CaO ratio in the molten pool is 1.0.

[0046] The slag-salt separation furnace 1 is heated by electrodes, with an average molten pool temperature of 850℃. It utilizes the density difference between molten slag and molten salt (molten slag ρ≈2.8t / m³). 3 ) and molten salt (ρ≈1.8t / m 3 The two high-temperature melts in the furnace are separated into layers. The upper layer is the molten salt layer, which is discharged through the salt discharge port 102. The lower layer is the molten slag layer, which flows from the arch to the slag discharge port 101 to obtain molten slag, thus realizing the primary slag-salt separation.

[0047] The slag from the slag discharge port 101 enters the quenching and homogenizing furnace 2 through the slag chute 4. Quartz sand and bauxite are fed into the quenching and homogenizing furnace 2 from the feed port. The materials are heated by electrodes, and the average temperature of the molten pool is 1500℃. After the materials are quenched, clarified and homogenized in the quenching and homogenizing furnace 2, a new slag with a single composition is obtained. It then flows through the arch to the quenching and slag discharge port 202 to obtain the target slag with SiO2 / CaO=1.8.

[0048] Molten salt from the salt outlet 102 enters the molten salt electrolysis furnace 3 through the molten salt chute 5. The average temperature of the molten pool is 750℃. The electrode plate 305 consists of two sets of anode-cathode plates 305. The molten salt removes impurity elements under the electrolysis of the electrode plate 305, and then flows through the arch to the purification salt outlet 302 to obtain the target molten salt.

[0049] The fly ash residue salt separation, conditioning and purification method of the second specific embodiment of the present invention has the following advantages: The process was simplified by using glyphosate waste salt as a flux, which significantly reduced the melting temperature and energy consumption, and lowered the operating costs of the process.

[0050] To improve resource utilization efficiency, the separated slag and molten salt are fed into the conditioning and homogenizing furnace 2 and the molten salt electrolysis furnace 3, respectively. Through fine processing (such as SiO2 / CaO ratio control and electrolytic impurity removal), high-purity products are obtained to meet the resource utilization needs of building materials, chemical raw materials and other industries.

[0051] To achieve the goal of zero landfill, a systematic design (such as sealed chute connections and centralized flue gas treatment) is used to ensure the complete resource utilization of salt and slag in fly ash and avoid secondary pollution.

[0052] In summary, the fly ash residue salt separation, conditioning and purification method of the present invention solves the problems of complex processes, high energy consumption and low resource utilization rate in related technologies through structural design and process optimization, and provides a new technical path for the efficient, clean and resource-based disposal of waste incineration fly ash.

[0053] The fly ash, slag, and salt separation, conditioning, and purification system of the present invention is described below with reference to the accompanying drawings. The fly ash, slag, and salt separation, conditioning, and purification system uses the fly ash, slag, and salt separation, conditioning, and purification method described in the above embodiments to treat the fly ash from waste incineration.

[0054] like Figure 1 As shown, the fly ash slag salt separation, conditioning and purification system of this embodiment includes a slag salt separation furnace 1, a conditioning and homogenization furnace 2 and a molten salt electrolysis furnace 3.

[0055] The slag-salt separator 1 is equipped with a slag discharge port 101, a salt discharge port 102, and a first feed port 107. The slag discharge port 101 is located at the lower part of the slag-salt separator 1, through which the lower layer of molten slag is discharged. The salt discharge port 102 is located at the upper part of the slag-salt separator 1, through which the upper layer of molten salt is discharged. The first feed port 107 is located at the top of the slag-salt separator 1, through which dehydrated powdered fly ash and quartz sand are fed into the slag-salt separator 1.

[0056] The quenching and homogenizing furnace 2 is equipped with a slag inlet 201, a quenching and slag discharge outlet 202, and a second feeding outlet 207. The slag inlet 201 is located at the top of the furnace, and its height is lower than that of the slag discharge outlet 101. The slag inlet 201 is connected to the slag discharge outlet 101 via a slag chute 4, allowing the slag from the slag discharge outlet 101 to enter the furnace 2. The second feeding outlet 207 is located at the top of the furnace 2, through which quartz sand and bauxite are fed. The quenching and slag discharge outlet 202 is located at the bottom of the furnace 2. After the material is quenched, clarified, and homogenized within the furnace 2, a new slag with a single composition is obtained and discharged through the quenching and slag discharge outlet 202, yielding the target slag.

[0057] The molten salt electrolysis furnace 3 is equipped with a molten salt inlet 301 and a purified salt outlet 302. The molten salt inlet 301 is located at the upper part of the molten salt electrolysis furnace 3, and its height is lower than that of the salt outlet 102. The molten salt inlet 301 is connected to the salt outlet 102 through a molten salt chute 5, and the molten salt from the salt outlet 102 enters the molten salt electrolysis cell through the molten salt chute 5. The purified salt outlet 302 is located at the lower part of the molten salt electrolysis furnace 3 and is used to discharge the target molten salt after electrolytic purification in the molten salt electrolysis furnace 3.

[0058] The fly ash slag-salt separation, conditioning, and purification system of this invention organically connects the slag-salt separation furnace 1, the conditioning and homogenization furnace 2, and the molten salt electrolysis furnace 3 to achieve stable and continuous output of molten slag and molten salt. The molten slag and molten salt are respectively conditioned, clarified, and homogenized in their respective equipment to obtain the target molten slag and target molten salt, laying the foundation for subsequent resource utilization.

[0059] Optionally, such as Figure 1 As shown, the slag-salt separation furnace 1, the conditioning and homogenizing furnace 2, and the molten salt electrolysis furnace 3 are all equipped with partition walls. The partition walls divide the chambers inside the furnace into two, and there are arched openings below the partition walls to connect the two chambers.

[0060] For example, the slag-salt separation furnace 1 is provided with a first partition wall 103, which divides the furnace chamber into two. One chamber is connected to the slag discharge port 101, and the other chamber is connected to the salt discharge port 102. Below the first partition wall 103, there is a first arch 104, which connects the two chambers so that the molten slag in the lower layer of the furnace can flow from the first arch 104 to the slag discharge port 101.

[0061] The quenching and homogenizing furnace 2 is equipped with a second partition wall 203, which divides the furnace chamber into two. One chamber is connected to the slag inlet 201, and the other chamber is connected to the quenching and homogenizing slag outlet 202. Below the second partition wall 203, there is a second arch 204, which connects the two chambers so that the new slag with a single composition obtained from quenching, clarification, and homogenization flows from the second arch 204 to the quenching and homogenizing slag outlet 202.

[0062] The molten salt electrolysis furnace 3 is equipped with a third partition wall 303, which divides the furnace chamber into two. One chamber is connected to the molten salt inlet 301, and the other chamber is connected to the purification and discharge outlet 302. Below the third partition wall 303, there is a third arch 304, which connects the two chambers so that the molten salt after electrolytic purification can flow from the third arch 304 to the purification and discharge outlet 302.

[0063] Therefore, the slag-salt separation furnace 1, the conditioning and homogenizing furnace 2, and the molten salt electrolysis furnace 3 are all composed of two chambers, with an arched opening below the partition wall to enable continuous discharge.

[0064] Optionally, the slag chute 4 is equipped with a heat preservation device and a fuel combustion gun is provided inside the slag chute 4 to keep the temperature of the slag inside the slag chute 4 above the solidification temperature, in other words, to prevent the slag from freezing in the chute.

[0065] Optionally, such as Figure 1 As shown, electrodes are installed in both the slag-salt separation furnace 1 and the conditioning and homogenizing furnace 2. The electrodes are used to heat the furnace.

[0066] For example, the slag-salt separation furnace 1 is equipped with a first electrode 105, which controls the temperature inside the slag-salt separation furnace 1 within the range of 800 to 1350°C. The conditioning and homogenizing furnace 2 is equipped with a second electrode 205, which controls the temperature inside the conditioning and homogenizing furnace 2 within the range of 1400 to 1600°C.

[0067] Furthermore, such as Figure 1 As shown, the molten salt electrolysis furnace 3 is equipped with an electrode plate 305, which includes one or more sets of anode-cathode pairs. The molten salt removes impurity elements under the electrolysis of the electrode plate 305.

[0068] Optionally, such as Figure 1 As shown, the top of the slag-salt separation furnace 1 is provided with a first flue 106, the top of the conditioning and homogenizing furnace 2 is provided with a second flue 206, and the top of the molten salt electrolysis furnace 3 is provided with a third flue 306. The slag-salt separation furnace 1, the conditioning and homogenizing furnace 2, and the molten salt electrolysis furnace 3 are all provided with flues so that the process flue gas can be centrally treated and ultimately discharged in compliance with standards.

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0070] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0071] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0072] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0073] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for separating, conditioning, and purifying fly ash residue salt, characterized in that, include: Dehydrated fly ash and auxiliary materials are transported into the slag-salt separation furnace according to a preset ratio; The slag-salt separation furnace is heated by electrodes and uses the density difference between molten slag and molten salt to separate the two high-temperature melts in the furnace into two layers. The upper layer is the molten salt layer, which is discharged through the salt discharge port of the slag-salt separation furnace. The lower layer is the molten slag layer, which flows through the arch in the slag-salt separation furnace to the slag discharge port. The molten slag discharged from the slag-salt separation furnace is fed into the conditioning and homogenizing furnace through the molten slag chute. The cold material is fed into the furnace through the feeding port of the conditioning and homogenizing furnace. The conditioning and homogenizing furnace heats the material through electrodes. After the material is conditioned, clarified and homogenized in the conditioning and homogenizing furnace, a target molten slag with a single composition is obtained. The target molten slag flows from the arch in the conditioning and homogenizing furnace to the slag discharge port and is discharged. The molten salt discharged from the slag-salt separation furnace is fed into the molten salt electrolysis furnace through the molten salt chute. After the molten salt passes through the electrode plates of the molten salt electrolysis furnace to remove impurity elements, the target molten salt is obtained. The target molten salt flows from the arch in the molten salt electrolysis furnace to the salt discharge port and is discharged.

2. The method for separating, conditioning, and purifying fly ash residue salt according to claim 1, characterized in that, The fly ash from waste incineration is dehydrated using steam to reduce the moisture content of the fly ash fed into the slag-salt separator to ≤1%.

3. The method for separating, conditioning, and purifying fly ash residue salt according to claim 1, characterized in that, Fly ash is the main material, with a mass fraction of 50-100%. The auxiliary materials include a Class I flux with a mass fraction of 0-50% and a Class II flux with a mass fraction of 0-20%. The Class I flux includes NaCl, CaCl2, NaCl+CaCl2, or solid waste containing chloride salts, such as fly ash from hazardous waste incineration and waste salt. The Class II flux includes quartz sand (SiO2) or siliceous solid waste.

4. The method for separating, conditioning, and purifying fly ash residue salt according to claim 1, characterized in that, The temperature in the slag-salt separation furnace is controlled at 800–1350℃, the temperature in the conditioning and homogenization furnace is controlled at 1400–1600℃, and the temperature in the molten salt electrolysis furnace is controlled at 700–1000℃.

5. The method for separating, conditioning, and purifying fly ash residue salt according to claim 1, characterized in that, The density of molten slag in the slag-salt separation furnace is 2.6–3.0 t / m³, and the density of molten salt in the slag-salt separation furnace is 1.8–2.0 t / m³.

6. A fly ash slag salt separation, conditioning and purification system, characterized in that, The fly ash slag salt separation, conditioning and purification system uses the fly ash slag salt separation, conditioning and purification method according to any one of claims 1-5 to treat the fly ash from waste incineration, and the fly ash slag salt separation, conditioning and purification system includes: A slag-salt separation furnace is provided with a slag discharge port and a salt discharge port, wherein the slag discharge port is located at the lower part of the slag-salt separation furnace and the salt discharge port is located at the upper part of the slag-salt separation furnace; A quenching and homogenizing furnace is provided with a slag inlet and a quenching and homogenizing slag outlet. The slag inlet is connected to the slag outlet through a slag chute. The quenching and homogenizing slag outlet is used to discharge the target slag after quenching, clarifying and homogenizing in the quenching and homogenizing furnace. A molten salt electrolysis furnace is provided with a molten salt inlet and a purified salt outlet. The molten salt inlet is connected to the purified salt outlet through a molten salt chute. The purified salt outlet is used to discharge the target molten salt after electrolytic purification in the molten salt electrolysis furnace.

7. The fly ash slag salt separation, conditioning and purification system according to claim 6, characterized in that, The slag-salt separation furnace, the conditioning and homogenizing furnace, and the molten salt electrolysis furnace are all equipped with partition walls. The partition walls divide the chambers inside the furnace into two, and an arched opening is provided below the partition walls to connect the two chambers.

8. The fly ash slag salt separation, conditioning and purification system according to claim 6, characterized in that, The slag chute is equipped with a heat preservation device and a fuel combustion gun is installed inside the slag chute to keep the temperature of the slag inside the slag chute above the solidification temperature.

9. The fly ash slag salt separation, conditioning and purification system according to claim 6, characterized in that, Both the slag-salt separation furnace and the conditioning and homogenizing furnace are equipped with electrodes for supplying heat to the furnace. The molten salt electrolysis furnace is equipped with electrode plates, which include one or more sets of anode-cathode pairs.

10. The fly ash slag salt separation, conditioning and purification system according to claim 6, characterized in that, The slag-salt separation furnace, the conditioning and homogenizing furnace, and the molten salt electrolysis furnace are all equipped with flues.

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