Airlift crystallization device and use method thereof

Abstract

The invention discloses an airlift crystallization device, which relates to the technical field of salt crystallization and comprises an evaporation chamber, an airlift pipe, a lower circulating pipe, a lower circulating pipe heater and a crystallization chamber, the evaporation chamber is provided with an exhaust pipe for exhausting non-condensable gas; the airlift pipe generates an airlift effect by injecting compressed air to drive materials to rise from the evaporation chamber to the crystallization chamber; the lower circulating pipe is connected with the evaporation chamber and the crystallization chamber to realize downward circulation of materials; the lower circulating pipe heater is arranged on the lower circulating pipe in a sleeving manner and is provided with an expansion joint and a baffle plate to compensate thermal stress and optimize heat exchange; and the crystallization chamber is provided with a material foot and a discharge pipe for collecting and discharging mature crystals. Through the synergistic effect of a circulation mechanism driven by the airlift tube and the lower circulation tube heater, mechanical damage of a traditional mechanical pump to crystal particles is effectively avoided, uniform growth and particle size increase of salt crystals in the crystallization chamber are promoted, preparation of salt products with full particles and large granularity is achieved, and meanwhile energy consumption and noise are reduced.

Description

Technical Field

[0001] This invention relates to the field of salt crystallization technology, and in particular to an airlift crystallization apparatus and its method of use. Background Technology

[0002] Currently, the production of many salt products mainly involves evaporation followed by crystallization. Due to structural limitations and production rates of the evaporation crystallization equipment, the crystallized salt products generally have small particle sizes and wide particle size distributions, typically less than 1 mm. The main reason for this is that during the crystallization of various salts, the high-speed rotation of the circulating pump blades beats, cuts, and impacts the crystallizing salts, causing the crystals to break and produce disproportionate crystals. This results in crystals failing to grow and an increase in deformed crystals.

[0003] As various industries have raised requirements for the particle size of salt products—for example, the food, environmental protection, and fertilizer industries demand larger-particle salt—they need salt products with larger particle sizes during the crystallization process for ease of use. For instance, the catering industry prefers larger, coarser salt particles for plating grilled and fried foods, the fertilizer industry favors larger salt crystals for better mixing with other elements and less powder stratification, and the road administration industry also prefers larger-particle salt for easier application when using de-icing salt. Therefore, there is an urgent need for an airlift-type circulating crystallization device to avoid damage to the crystals caused by mechanical pumps and to achieve uniform crystal growth and increased particle size. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned deficiencies in existing evaporation crystallization equipment by providing an airlift circulating crystallization device to achieve larger and fuller crystal particles in salt products during the crystallization process, thereby meeting the demand for large-particle salt products in industries such as food, environmental protection, fertilizer, and road administration.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an airlift crystallization device, comprising: an evaporation chamber, an airlift pipe, a lower circulation pipe, a lower circulation pipe heater, and a crystallization chamber, wherein the lower circulation pipe heater is sleeved on the lower circulation pipe; The evaporation chamber includes an evaporation chamber head, an evaporation chamber cylinder, an evaporation chamber lower cone, and an evaporation chamber exhaust pipe. The evaporation chamber exhaust pipe is located at the top of the evaporation chamber head and is used to discharge non-condensable gases generated during evaporation. The air riser includes an air riser outlet, an air riser body, an air riser mixer sleeve, and an air riser inlet. The air riser body, air riser outlet, and air riser inlet are integrally welded structures to ensure the continuity and sealing of gas-liquid mixing. The lower circulation pipe heater includes a heater sealing surface, a heater cylinder, a heater cylinder expansion joint, and a heater cylinder baffle. The heater cylinder is provided with a heater heat medium inlet and a heater heat medium outlet. The crystallization chamber includes a crystallization chamber head, a crystallization chamber cylinder, a crystallization chamber material foot, and a crystallization chamber discharge pipe. The crystallization chamber discharge pipe is located at the bottom of the crystallization chamber material foot and is used to discharge mature crystals.

[0006] As a preferred embodiment of the airlift crystallization device of the present invention, wherein: an airlift pipe inlet and a circulating material outlet are provided at the bottom of the lower cone of the evaporation chamber; an airlift pipe connection outlet, a gas discharge outlet and a lower circulating material return port are provided on the end cap of the crystallization chamber; the airlift pipe outlet is connected to the crystallization chamber through the airlift pipe connection outlet, and the airlift pipe inlet is connected to the evaporation chamber through the airlift pipe inlet, forming an airlift-driven material circulation path.

[0007] As a preferred embodiment of the airlift crystallization device of the present invention, one end of the lower circulation pipe is connected to the evaporation chamber through the circulation material outlet on the lower cone of the evaporation chamber, and the other end is connected to the crystallization chamber through the lower circulation material return port on the crystallization chamber head. The lower circulation pipe is used to realize the downward circulation of materials and promote the heat and mass exchange between the crystallization chamber and the evaporation chamber.

[0008] In a preferred embodiment of the airlift crystallization device of the present invention, an evaporation chamber support is fitted on the evaporation chamber cylinder, and a crystallization chamber support is fitted on the crystallization chamber cylinder, wherein both the evaporation chamber support and the crystallization chamber support are steel support components.

[0009] As a preferred embodiment of the airlift crystallization device of the present invention, wherein: the airlift pipe body is provided with evenly distributed air holes for the injection of compressed air to generate an airlift effect, the airlift pipe mixer sleeve is coaxially fitted in the air hole area of ​​the airlift pipe body, and the two ends of the airlift pipe mixer sleeve are sealed and connected.

[0010] As a preferred embodiment of the airlift crystallization device of the present invention, the heater sealing surface is a steel sealing element, used for the concentric fitting and end face sealing of the lower circulation pipe heater and the lower circulation pipe.

[0011] In a preferred embodiment of the airlift crystallization device of the present invention, the heater cylinder expansion joint is a deformable steel section located in the middle of the heater cylinder; after the heat medium is introduced, the heater cylinder expansion joint of the lower circulation pipe heater compensates for the deformation of the cylinder and releases thermal stress through deformation.

[0012] As a preferred embodiment of the airlift crystallization device of the present invention, the heater cylinder baffle is a semi-open stainless steel baffle, which is spaced apart in the inner cavity of the heater cylinder to guide the heat medium so that it can complete the heat exchange more effectively.

[0013] As a preferred embodiment of the airlift crystallization device of the present invention, the material foot of the crystallization chamber is a stainless steel cone that gradually tapers from top to bottom, and the bottom is connected to the crystallization chamber discharge pipe for collecting salt particles generated during the crystallization process.

[0014] A method of using an airlift crystallizer includes the following steps: S1: Pump the crystallization mother liquor and salt slurry into the evaporation chamber. The mother liquor flows into the crystallization chamber through the lower circulation pipe until the liquid levels in the evaporation chamber and the crystallization chamber reach the set height. S2: Compressed air is introduced into the air riser mixer sleeve. The compressed air enters the air riser through the air holes on the air riser body and mixes with the mother liquor to form a gas-liquid emulsion flow. Under the action of the air rise effect, the mother liquor and the suspended salt particles in it are driven to rise from the evaporation chamber to the crystallization chamber. S3: Start the lower circulation pipe heater. The heat medium enters from the heater heat medium inlet, flows through the heater cylinder and is guided by the baffle plate to heat the mother liquor circulating downward and maintain the temperature required for crystallization. S4: In the crystallization chamber, the salt particles in the mother liquor gradually grow, and the fine crystals re-enter the air riser pipe with the circulating mother liquor. The mature crystals settle in the material foot of the crystallization chamber due to the increase in particle size. S5: When the crystals in the crystallization chamber reach the set particle size, open the crystallization chamber discharge pipe to discharge the mature crystals; S6: Non-condensable gases and secondary steam generated during evaporation are discharged through the exhaust pipe of the evaporation chamber, while the gas outlet at the top of the crystallization chamber remains open to ensure system pressure balance and achieve continuous crystallization operation.

[0015] The beneficial effects of this invention are: 1. This invention can change the flow rate, emulsification ratio, and lifting force in the airlift pipe by changing the pressure, flow rate, and suction port position of the injected compressed air. This allows for the adjustment of different sorting particle sizes to meet the requirements of different crystal particle sizes and products, promote uniform crystal growth, and reduce the generation of deformed crystals. 2. Compared with using a circulating pump to generate material circulation, the airlift method does not cause damage to the salt particles because there are no blades hitting the salt particles and the lifting force is gentle. At the same time, since no high-power circulating pump is working during the airlift process, the noise and energy consumption are lower, improving the operating environment and reducing operating costs. 3. The lower circulation pipe heater is equipped with an expansion joint and baffles, which can compensate for thermal stress and optimize the flow of heat medium, ensuring that the mother liquor is heated evenly in the downward circulation and maintaining the crystallization rate; combined with the integrated welded air riser and stainless steel cone design, it promotes the thermal and mass balance between the evaporation chamber and the crystallization chamber and shortens the crystallization cycle.

[0016] 4. The exhaust pipe of the evaporation chamber and the gas outlet of the crystallization chamber effectively remove non-condensable gases and secondary steam, reducing volatile emissions; the material foot air purging mechanism assists in the discharge of mature crystals, avoids excessive precipitation, and ensures process continuity and product purity.

[0017] 5. The entire device is made of stainless steel, with a simple structure and convenient installation. It can be installed in existing equipment and facilities, making it suitable for new construction, renovation and expansion projects in various factories and applicable to a variety of salt production scenarios. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the structure of an airlift crystallization device according to the present invention.

[0019] Figure 2 This is a diagram showing the configuration of the evaporation chamber in this invention.

[0020] Figure 3 This is a diagram of the air riser structure in this invention.

[0021] Figure 4 This is a diagram illustrating the structure of the lower circulation tube heater in this invention.

[0022] Figure 5 This is a diagram showing the structure of the crystallization chamber in this invention.

[0023] Figure 6 This is a schematic diagram of the principle of an airlift crystallization device according to the present invention.

[0024] Figure 7 This is a schematic diagram illustrating the working principle of the crystallization chamber in this invention.

[0025] Figure Descriptions: 101. Evaporation chamber; 101a. Evaporation chamber end cap; 101b. Evaporation chamber cylinder; 101c. Lower cone of evaporation chamber; 101d. Evaporation chamber exhaust pipe; 101e. Evaporation chamber support; 102. Air riser pipe; 102a. Air riser pipe outlet; 102b. Air riser pipe body; 102c. Air riser pipe mixer sleeve; 102d. Air riser pipe inlet; 103. Lower circulation pipe; 104. Lower circulation pipe reinforcement. Heater; 104a, Heater sealing surface; 104b, Heater heat medium inlet; 104c, Heater shell; 104d, Heater shell expansion joint; 104e, Heater shell baffle; 104f, Heater heat medium outlet; 105, Crystallization chamber; 105a, Crystallization chamber head; 105b, Crystallization chamber shell; 105c, Crystallization chamber support; 105d, Crystallization chamber material foot; 105e, Crystallization chamber discharge pipe. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0030] Reference Figures 1 to 7 This is one embodiment of the present invention, which provides an airlift crystallization device, comprising: an evaporation chamber 101, an airlift pipe 102, a lower circulation pipe 103, a lower circulation pipe heater 104, and a crystallization chamber 105, wherein the lower circulation pipe heater 104 is sleeved on the lower circulation pipe 103.

[0031] like Figure 2As shown, the evaporation chamber 101 includes an evaporation chamber head 101a, an evaporation chamber cylinder 101b, an evaporation chamber lower cone 101c, and an evaporation chamber exhaust pipe 101d. The evaporation chamber head 101a is made of stainless steel and has a certain strength and rigidity. The evaporation chamber cylinder 101b is also made of stainless steel and has a certain strength and rigidity to meet the usage requirements. Together with the evaporation chamber head 101a and the evaporation chamber lower cone 101c, it forms the evaporation chamber. The evaporation chamber lower cone 101c is made of stainless steel and has a certain taper to collect and concentrate solid salt particles in the salt slurry in the evaporation chamber. The evaporation chamber exhaust pipe 101d is located at the top of the evaporation chamber head 101a and is used to discharge non-condensable gases generated during evaporation. The evaporation chamber cylinder 101b is fitted with an evaporation chamber support 101e, which is a steel support component used to support the evaporation chamber 101 on a high platform.

[0032] like Figure 3 As shown, the air riser 102 includes an air riser outlet 102a, an air riser body 102b, an air riser mixer sleeve 102c, and an air riser inlet 102d. The air riser body 102b, air riser outlet 102a, and air riser inlet 102d are integrally welded structures to ensure the continuity and sealing of gas-liquid mixing. The air riser outlet 102a is a flared stainless steel pipe used to flare and slow down the brine slurry lifted from the air riser 102, preventing strong splashing of the brine slurry surface. The air riser body 102b is a seamless stainless steel pipe, through which the circulating brine slurry and other materials are lifted. The internal flow passes through the compressed air injection area, which has evenly distributed air holes for compressed air injection. To achieve better gas mixing, the pipe is generally longer than 10 meters. The air riser mixer sleeve 102c is a stainless steel sleeve that fits into the air holes of the air riser body 102b. The two ends of the air riser mixer sleeve 102c are sealed to ensure that the compressed air inside does not leak. The compressed air can be injected into the air riser 102 through the evenly distributed air holes on the air riser body 102b and mixed with the salt slurry. The air riser inlet 102d is a flared stainless steel pipe used to draw in circulating salt slurry.

[0033] like Figure 4 As shown, the lower circulation pipe heater 104 includes a heater sealing surface 104a, a heater cylinder 104c, a heater cylinder expansion joint 104d, and a heater cylinder baffle 104e. The heater cylinder 104c is provided with a heater heat medium inlet 104b and a heater heat medium outlet 104f. The heater cylinder 104c is a steel pressure-bearing cylinder used for the pressure bearing and flow of the internal heat medium; the heater sealing surface 104a is a steel sealing element used for the concentric fitting and end face sealing of the lower circulation pipe heater 104 and the lower circulation pipe 103 to prevent heat medium leakage; the heater cylinder expansion joint 104d is a steel deformable short section located in the middle of the heater cylinder 104c; after the heat medium is introduced into the lower circulation pipe heater 104, the heater cylinder expansion joint 104d compensates for the cylinder deformation and releases thermal stress through deformation; the heater cylinder baffle 104e is a stainless steel semi-open baffle, spaced at intervals in the inner cavity of the heater cylinder 104c, used to guide the heat medium to achieve more efficient heat exchange; the heater heat medium inlet 104b is a steel flange interface used to introduce heat medium, such as steam or heat transfer oil; the heater heat medium outlet 104f is a steel flange interface used to exit heat medium, such as condensate or heat transfer oil.

[0034] like Figure 5 As shown, the crystallization chamber 105 includes a crystallization chamber head 105a, a crystallization chamber cylinder 105b, a crystallization chamber material foot 105d, and a crystallization chamber discharge pipe 105e. The crystallization chamber discharge pipe 105e is located at the bottom of the crystallization chamber material foot 105d and is used to discharge mature crystals. Among them, the crystallization chamber head 105a is a stainless steel head with certain strength and rigidity, and the interface is opened according to the usage requirements; the crystallization chamber cylinder 105b is a stainless steel cylinder with certain strength and rigidity to meet the usage requirements, and its volume is based on the crystallization amount and crystallization time of different substances; the crystallization chamber material foot 105d is a stainless steel cone that gradually tapers from top to bottom, and the bottom is connected to the crystallization chamber discharge pipe 105e for collecting the salt particles generated during the crystallization process. Among them, a crystallization chamber support 105c is fitted on the crystallization chamber cylinder 105b. The crystallization chamber support 105c is a steel support component used to support the crystallization chamber 105.

[0035] like Figure 1 As shown, the bottom of the lower cone 101c of the evaporation chamber is provided with an air riser inlet and a circulating material outlet, and the crystallization chamber head 105a is provided with an air riser outlet, a gas outlet, and a lower circulating material return port; the air riser outlet 102a of the air riser 102 is connected to the crystallization chamber 105 through the air riser outlet, and the air riser inlet 102d is connected to the evaporation chamber 101 through the air riser inlet, forming an air rise-driven material circulation path; one end of the lower circulation pipe 103 is connected to the evaporation chamber 101 through the circulating material outlet on the lower cone 101c of the evaporation chamber, and the other end is connected to the crystallization chamber 105 through the lower circulating material return port on the crystallization chamber head 105a. The lower circulation pipe 103 is used to realize the downward circulation of materials and promote the heat and mass exchange between the crystallization chamber and the evaporation chamber.

[0036] like Figure 6 , Figure 7As shown, the method of implementing the present invention is as follows: During operation, the crystallization mother liquor and salt slurry are first pumped into the evaporation chamber 101. Since the evaporation chamber 101 is connected to the crystallization chamber 105 through the lower circulation pipe 103, the mother liquor and salt slurry will enter the crystallization chamber 105 through the lower circulation pipe 103. The gas outlet at the top of the crystallization chamber 105 will be opened to prevent the formation of air pockets inside that would hinder the mother liquor and salt slurry from entering the crystallization chamber 105. The loading work is completed after the crystallization chamber 105 and the evaporation chamber 101 are filled to the specified liquid level. Liquid level gauges are installed on both the crystallization chamber 105 and the evaporation chamber 101 through liquid level gauge interfaces, and observation sight glasses are also provided to detect and observe the liquid level. When the device is started, compressed air is introduced into the air riser mixer sleeve 102c. The compressed air will enter the air riser 102 through the air holes on the air riser body 102b. After entering the air riser 102, the compressed air will quickly mix and emulsify with the mother liquor. At the same time, the gas will continuously expand due to its own buoyancy and float up along the pipe. Therefore, a lifting force is generated in the air riser 102 and the mother liquor in the pipe will start to rise and flow. The solid salt particles in the mother liquor will also rise with the mother liquor and enter the evaporation chamber 101 due to the emulsified bubbles attached to the surface. In the evaporation chamber 101, the mother liquor and salt slurry are slowed down due to volume change and collected in the evaporation chamber 101. They are then returned to the crystallization chamber 105 through the lower circulation pipe 103. The lifting gas in the mother liquor is released in the evaporation chamber 101 and discharged through the evaporation chamber exhaust pipe 101d. The secondary steam evaporated from the mother liquor is also discharged through the evaporation chamber exhaust pipe 101d at the same time. Since the evaporation process is an exothermic process, in order to maintain the heat and speed of crystallization, a certain amount of heat needs to be added to the mother liquor. Therefore, the mother liquor and salt slurry are heated by the lower circulation pipe heater 104 during the flow of the mother liquor and salt slurry through the lower circulation pipe 103. The mother liquor in the crystallization chamber 105 will crystallize and precipitate inside it. At the same time, due to the circulation effect generated by the air riser 102 and the lower circulation pipe 103, the mother liquor around the crystallized crystals circulates to assist crystal growth. Small crystals will also be sucked into the circulating mother liquor by the air riser 102 and enter the circulating mother liquor. After they grow to a certain particle size in the circulating mother liquor, they will stay in the crystallization chamber 105. Once the crystallized salt particles in the crystallization chamber 105 reach the required particle size, they are difficult to be sucked in by the air riser 102 and begin to precipitate in the crystallization chamber foot 105d and be discharged through the crystallization chamber discharge pipe 105e. The bottom of the crystallization chamber foot 105d has a compressed air inlet, which can be used to gently blow the precipitated crystallized salt particles with air before discharge (or periodically), so that the small-sized crystals in the precipitated crystallized salt particles float up and are sucked in by the air riser 102 for circulation.

[0037] In summary, this invention, through the circulation mechanism driven by the air riser 102 and the synergistic effect of the lower circulation pipe heater 104, effectively avoids mechanical damage to crystal particles caused by traditional mechanical pumps, promotes the uniform growth and particle size increase of salt crystals in the crystallization chamber, and achieves the preparation of salt products with full and large particle size. At the same time, it significantly reduces energy consumption and noise, and is suitable for the diverse needs of industries such as food, fertilizer and road administration.

[0038] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., the size, dimensions, structure, shape, and proportions of various elements), as well as parameter values ​​(e.g., temperature, pressure, etc.), installation arrangements, the use of materials, colors, orientations, etc.), without substantially departing from the novel teachings and advantages of the subject matter described in this application. For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise changed, and the nature or number or position of discrete elements may be altered or changed. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0039] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0040] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A gas-lift crystallization apparatus, characterized in that, include: Evaporation chamber (101), air riser (102), lower circulation pipe (103), lower circulation pipe heater (104) and crystallization chamber (105), wherein the lower circulation pipe heater (104) is sleeved on the lower circulation pipe (103); The evaporation chamber (101) includes an evaporation chamber head (101a), an evaporation chamber cylinder (101b), an evaporation chamber lower cone (101c), and an evaporation chamber exhaust pipe (101d). The evaporation chamber exhaust pipe (101d) is located at the top of the evaporation chamber head (101a) and is used to discharge non-condensable gases generated by evaporation. The air riser (102) includes an air riser outlet (102a), an air riser body (102b), an air riser mixer sleeve (102c), and an air riser inlet (102d). The air riser body (102b), air riser outlet (102a), and air riser inlet (102d) are integrally welded structures to ensure the continuity and sealing of gas-liquid mixing. The lower circulation pipe heater (104) includes a heater sealing surface (104a), a heater cylinder (104c), a heater cylinder expansion joint (104d), and a heater cylinder baffle (104e). The heater cylinder (104c) is provided with a heater heat medium inlet (104b) and a heater heat medium outlet (104f). The crystallization chamber (105) includes a crystallization chamber head (105a), a crystallization chamber cylinder (105b), a crystallization chamber material foot (105d), and a crystallization chamber discharge pipe (105e). The crystallization chamber discharge pipe (105e) is located at the bottom of the crystallization chamber material foot (105d) and is used to discharge mature crystals.

2. The airlift crystallizer according to claim 1, characterized in that: The bottom of the lower cone (101c) of the evaporation chamber is provided with an air riser inlet and a circulating material outlet. The head (105a) of the crystallization chamber is provided with an air riser outlet, a gas outlet and a lower circulating material return port. The air riser outlet (102a) of the air riser (102) is connected to the crystallization chamber (105) through the air riser outlet, and the air riser inlet (102d) is connected to the evaporation chamber (101) through the air riser inlet, forming an air rise-driven material circulation path.

3. The airlift crystallization apparatus according to claim 2, characterized in that: One end of the lower circulation pipe (103) is connected to the evaporation chamber (101) through the circulating material outlet on the lower cone (101c) of the evaporation chamber, and the other end is connected to the crystallization chamber (105) through the lower circulation material return port on the crystallization chamber head (105a). The lower circulation pipe (103) is used to realize the downward circulation of materials and promote the heat and mass exchange between the crystallization chamber and the evaporation chamber.

4. The airlift crystallization apparatus according to claim 1, characterized in that: An evaporation chamber support (101e) is fitted onto the evaporation chamber cylinder (101b), and a crystallization chamber support (105c) is fitted onto the crystallization chamber cylinder (105b). Both the evaporation chamber support (101e) and the crystallization chamber support (105c) are steel support components.

5. The airlift crystallizer according to claim 1, characterized in that: The air riser tube body (102b) has evenly distributed air holes for injecting compressed air to generate an air rise effect. The air riser mixer sleeve (102c) is coaxially fitted in the air hole area of ​​the air riser tube body (102b), and the two ends of the air riser mixer sleeve (102c) are sealed together.

6. The airlift crystallization apparatus according to claim 1, characterized in that: The heater sealing surface (104a) is a steel sealing element used for the concentric fitting and end face sealing of the lower circulation pipe heater (104) and the lower circulation pipe (103).

7. The airlift crystallization apparatus according to claim 1, characterized in that: The heater cylinder expansion joint (104d) is a deformable steel short section, which is located in the middle of the heater cylinder (104c). After the heat medium is introduced, the heater cylinder expansion joint (104d) compensates for the deformation of the cylinder and releases thermal stress by deforming.

8. The airlift crystallizer according to claim 1, characterized in that: The heater cylinder baffle (104e) is a semi-open stainless steel baffle, which is spaced apart in the inner cavity of the heater cylinder (104c) to guide the heat medium so that it can complete the heat exchange more effectively.

9. The airlift crystallization apparatus according to claim 1, characterized in that: The crystallization chamber feed foot (105d) is a stainless steel cone that tapers gradually from top to bottom, and its bottom is connected to the crystallization chamber discharge pipe (105e) for collecting salt particles generated during the crystallization process.

10. A method of using an airlift crystallizer, based on the airlift crystallizer according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1: Pump the crystallization mother liquor and salt slurry into the evaporation chamber (101), and the mother liquor flows into the crystallization chamber (105) through the lower circulation pipe (103) until the liquid levels in the evaporation chamber and the crystallization chamber reach the set height; S2: Compressed air is introduced into the air riser mixer sleeve (102c). The compressed air enters the air riser (102) through the air holes on the air riser body (102b) and mixes with the mother liquor to form a gas-liquid emulsion flow. Under the action of the air rise effect, the mother liquor and the suspended salt particles therein are driven to rise from the evaporation chamber to the crystallization chamber (105). S3: Start the lower circulation pipe heater (104). The heat medium enters from the heater heat medium inlet (104b), flows through the heater cylinder (104c) and is guided by the baffle plate (104e) to heat the mother liquor circulating downward and maintain the temperature required for crystallization. S4: In the crystallization chamber (105), the salt particles in the mother liquor gradually grow, and the fine crystals re-enter the air riser (102) with the circulating mother liquor. The mature crystals settle in the crystallization chamber foot (105d) due to the increase in particle size. S5: When the crystals in the crystallization chamber foot (105d) reach the set particle size, open the crystallization chamber outlet pipe (105e) to discharge the mature crystals; S6: Non-condensable gases and secondary steam generated during evaporation are discharged through the evaporation chamber exhaust pipe (101d). The gas outlet at the top of the crystallization chamber (105) remains open to ensure system pressure balance and achieve continuous crystallization operation.

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