Solar refined salt preparation device and method

Abstract

The invention discloses a solar refined salt preparation device and method, the device comprises a concentration / salt extraction part, stirring parts, leakage tanks and a water tank, the concentration / salt extraction part is located in the middle of the liquid level of the water tank, the stirring parts are located on the two sides of the liquid level of the water tank, and the leakage tanks are arranged below the stirring parts; the concentration / salt extraction part comprises a salt extraction plate, a heat insulation bearing part, a concentration evaporator and a salt extraction evaporator; the two ends of the heat insulation bearing part are installed on the water tank, the multiple concentration evaporators are arranged in the middle of the heat insulation bearing part, the multiple salt extraction evaporators are arranged on the two sides of the concentration evaporators and located on the heat insulation bearing part, the salt extraction plate is arranged below the salt extraction evaporators, and the leakage groove is located below the salt extraction plate. The problems of high energy consumption, complex equipment, long evaporation period and the like in the existing refined salt preparation process are solved, concentrated seawater and sea salt solids are synchronously obtained by utilizing solar interface evaporation, calcium and magnesium impurities are removed based on the self-concentration and solubility difference among all components of the sea salt, and efficient and simple preparation of the refined salt is realized.

Description

Technical Field

[0001] This invention belongs to the field of solar-powered refined salt production, specifically relating to a solar-powered refined salt production apparatus and method. Background Technology

[0002] Salt production is an ancient yet popular technology, with common existing methods including the salt pan method, electrodialysis, and reverse osmosis. The salt pan method is the most basic method for producing edible salt. It utilizes sunlight and wind power to evaporate and concentrate seawater for crystallization. After being brought to a tidal state, the seawater is introduced into multi-stage evaporation ponds for concentration. Raw salt precipitates in the crystallization ponds, and then undergoes washing, desalination, chemical impurity removal, vacuum crystallization, drying, and sieving to produce edible salt. The salt pan method requires a large area, has a long production cycle, and generates chemical waste such as calcium carbonate. The electrodialysis method utilizes an ion exchange membrane in a direct current electric field to selectively migrate ions, achieving brine concentration. Seawater pretreatment is followed by passage through an electrodialysis unit, and the concentrate is directly purified into edible salt through vacuum crystallization. However, electrodialysis equipment has high technical requirements and high maintenance costs; the ion exchange membrane needs regular cleaning and replacement, and the electrically driven equipment consumes a lot of energy. The reverse osmosis method pressurizes seawater through a semi-permeable membrane, trapping salt to form concentrated brine. After seawater pretreatment, it passes through a reverse osmosis system, producing concentrated brine as a byproduct. This concentrated brine is then processed through vacuum salt production and evaporation crystallization to obtain refined edible salt. Reverse osmosis membranes are susceptible to fouling, seawater requires strict pretreatment, initial equipment investment is high, and large-scale production depends on supporting seawater desalination projects. It is evident that existing refined salt production methods have limitations such as high energy consumption, complex equipment structure, long evaporation and salt extraction cycles, large land area requirements, and high operation and maintenance costs. To reduce costs and increase efficiency, alleviate land use pressure, and achieve sustainable development, refined salt production methods must inevitably develop towards high efficiency, economy, and low energy consumption.

[0003] Currently, solar thermal interface evaporation technology has shown great potential in the field of solar thermal utilization, and is expected to develop new solutions for the green production of refined salt. As a technology that directly converts solar energy into heat energy to drive water evaporation at the interface, sunlight irradiates the evaporation interface layer to achieve localized heating and high temperatures, confining the heat energy to the surface area rather than the entire water body. This reduces heat loss while enhancing water evaporation, offering advantages such as high efficiency, cleanliness, and ease of deployment. Currently, solar interface evaporation technology is mainly applied in seawater desalination and crude salt separation. Existing research has demonstrated that through optimized evaporator structure design, solar interface evaporation technology can completely separate water and salt; however, for refined salt production applications, a method for selectively separating sodium chloride from the complex components of sea salt is still lacking. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention aims to provide a solar-powered refined salt production device and method. This method utilizes solar energy to perform interfacial evaporation of seawater, simultaneously obtaining concentrated seawater and sea salt solids. Based on the differences in concentration and solubility among the components of sea salt, concentrated seawater with near-saturation of sodium chloride is used to physically wash the extracted sea salt solids, removing most potassium, magnesium, and calcium components. This achieves efficient and simple refined salt production with low energy consumption, solving the problems of high energy consumption, complex equipment structure, and long evaporation cycles in existing refined salt production methods. This invention is achieved through the following technical solution: A solar-powered refined salt production device includes a salt concentration / extraction component, a stirring component, a trough, and a water tank. The salt concentration / extraction component is located in the middle of the liquid surface in the water tank, the stirring component is located on both sides of the liquid surface in the water tank, and a trough is provided below each stirring component. The concentration / salt extraction component includes a salt extraction plate, a heat insulation support, a concentration evaporator, and a salt extraction evaporator. The two ends of the heat insulation support are installed on the water tank. Multiple concentration evaporators are arranged in the middle of the heat insulation support. Multiple salt extraction evaporators are arranged on both sides of the concentration evaporator and on the heat insulation support. The salt extraction plate is arranged below the salt extraction evaporator. The trough is located below the salt extraction plate.

[0005] Furthermore, the concentrator includes a trapezoidal light-absorbing layer, a trapezoidal upper photothermal layer, and a trapezoidal lower photothermal layer arranged sequentially from top to bottom. The bottom two ends of the trapezoidal lower photothermal layer are respectively connected to a narrow water conveying layer that bends downwards into the water and an inner wide water conveying layer. The long bottom edge of the trapezoidal upper photothermal layer is connected to an outer wide water conveying layer that bends downwards into the water. The narrow water conveying layer, the inner wide water conveying layer, and the outer wide water conveying layer are used to draw seawater from the lower tank to the trapezoidal light-absorbing layer for evaporation. After evaporation, salt ions flow back from the inner wide water conveying layer and the outer wide water conveying layer to the narrow water conveying layer into the tank, thereby achieving continuous concentration of seawater. The trapezoidal light-absorbing layer, the trapezoidal upper photothermal layer, and the trapezoidal lower photothermal layer are all trapezoids with a short bottom edge: long bottom edge: height ratio of 1:3:2~3. The multiple concentrators are staggered and spliced ​​together, with the short bottom edge connected to the long bottom edge in an alternating arrangement.

[0006] Furthermore, the salt extraction evaporator includes a salt extraction light-absorbing layer, an upper salt extraction photothermal layer, and a lower salt extraction photothermal layer arranged sequentially from top to bottom. The upper salt extraction photothermal layer is connected to an outer water conveying layer that bends downwards into the water at one end near the concentrator. The lower salt extraction photothermal layer is connected to an inner water conveying layer that bends downwards into the water at one end near the concentrator, and a salt guiding layer at the other end away from the concentrator, for extracting solid sea salt. The sides of the salt extraction light-absorbing layer, the upper salt extraction photothermal layer, and the lower salt extraction photothermal layer that are near the evaporator are adjacent to and parallel to the bottom sides of the trapezoidal light-absorbing layer, the upper trapezoidal photothermal layer, and the lower trapezoidal photothermal layer. The length of the trapezoidal light-absorbing layer, the upper trapezoidal photothermal layer, and the lower trapezoidal photothermal layer is the length of the long bottom side or the sum of the long bottom side and the short bottom side. The lower salt extraction photothermal layer is connected to the long bottom side of the trapezoidal salt guiding layer. The salt guiding layer is a trapezoid with a short bottom side: long bottom side: height ratio of 1:3:2~3.

[0007] Furthermore, the salt extraction light-absorbing layer, the upper salt extraction photothermal layer, and the lower salt extraction photothermal layer have the same shape, all of which are rectangles with a length-to-width ratio of 3~4:2~3 or right-angled trapezoids with a short base: long base: height ratio of 3:4:2~3; the long side of the rectangle or the long base of the right-angled trapezoid is closer to the side of the evaporator.

[0008] Furthermore, the salt-lifting plate is bent at 100~170° to form a fixed end and a salt-carrying end. The fixed end is fixed below the photothermal layer under the salt-lifting plate, and the salt-carrying end is located below the salt-guiding layer and its width is greater than the height of the trapezoidal salt-guiding layer.

[0009] Furthermore, the stirring component includes a power source, a motor mounting bracket, a rotating rod, a motor, a stirring rod, and stirring blades; the power source is fixedly installed above the motor mounting bracket, and the power source is electrically connected to the motor; the output shaft of the motor is connected to the stirring rod perpendicular to the liquid surface, and the other end of the stirring rod is equipped with stirring blades for stirring the concentrated seawater in the tank; the rotating rod is installed through the motor mounting bracket below, and the rotating rod is connected to the pre-drilled hole in the tank body by a socket joint, and is arranged through the tank body to realize the quick installation and removal of the motor mounting bracket.

[0010] Furthermore, the trough includes an upper frame, a mesh, a bottom frame, and a limiting rod. The limiting rod passes through the corresponding holes reserved in the upper frame, mesh, and bottom frame from top to bottom, forming an integrated assembly through the connection and positioning. The stirring blade is located inside the trough.

[0011] Furthermore, the length of the stirring rod is shorter than the distance from the lower surface of the motor fixing component to the surface of the mesh; the blade shape of the stirring blade is circular or rectangular, the distance from the edge of the blade to the stirring rod is controlled to be less than 5 mm, and the aperture of the mesh is ≤0.15 mm.

[0012] Furthermore, the ratio of the number of concentration evaporators to the number of salt extraction evaporators is 1:1.

[0013] The solar-powered refined salt production method based on the aforementioned device includes the following steps: S1: Add seawater to be treated into the water tank so that the narrow water delivery layer, the inner wide water delivery layer, and the outer wide water delivery layer of the evaporator, as well as the outer water delivery layer and the inner water delivery layer of the salt extraction evaporator, are immersed in seawater. S2: Allow the device to be naturally exposed to sunlight or simulated light sources. The trapezoidal light-absorbing layer of the evaporator absorbs solar energy and converts it into heat energy, heating the upper and lower photothermal layers of the trapezoid. Seawater is continuously adsorbed to the interface of the evaporator. The heat energy is confined to the evaporation interface to achieve local heating, and the seawater evaporates rapidly. Under the action of capillary force, salt ions are transported from bottom to top to the surface of the evaporator through the inner and outer wide water transport layers. The unidirectional flow drives the salt ions to flow back to the water tank along the direction from the lower photothermal layer to the narrow water transport layer, so that the seawater in the water tank is gradually concentrated to 10~24wt%. S3: The seawater that is continuously concentrated in the tank is adsorbed to the evaporation interface by the outer and inner water supply layers of the salt extraction evaporator. The salt extraction light-absorbing layer of the salt extraction evaporator absorbs solar energy and converts it into heat energy, which heats the upper and lower light-thermal layers of the salt extraction. The seawater evaporates rapidly, and salt ions flow in the direction of the salt guide layer and precipitate at the bottom of the salt guide layer. They naturally adhere to the salt extraction plate, and the precipitated sea salt solids slide off the salt-carrying end and fall into the trough. S4: When the seawater in the tank is concentrated and evaporated to 3 / 100-1 / 20 of its original volume, turn on the power supply to power the motor. The motor drives the stirring rod to rotate the stirring blades and stirs the concentrated seawater and sea salt in the trough. Using the principle of physical washing, the concentrated seawater and sea salt are fully contacted through stirring. Based on the differences in solubility and concentration between sea salt components, impurities such as calcium, potassium and magnesium ions in the sea salt are directly physically removed. S5: The refined salt obtained after physical washing in step S4 is trapped by the sieve of the trough. After stirring, the trough is removed and dried to obtain solid refined salt.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention offers higher solar evaporation rates and efficiency. It utilizes photothermal interface evaporation to concentrate seawater and extract solid sea salt, heating only the surface water molecules for rapid evaporation. Compared to bottom heating and overall heating, this results in less heat loss, rapidly increasing local temperature and accelerating surface water evaporation. The amount of water evaporated and salt produced per unit time is higher than traditional evaporation methods, demonstrating high efficiency. Simultaneously, through photothermal evaporation in both the concentration evaporator and the salt extraction evaporator, seawater and salt lake water can be efficiently and directly concentrated and solid sea salt extracted simultaneously. The auxiliary stirring component ensures sufficient physical contact between the concentrated brine and the sea salt, accelerating the dissolution and removal of impurity ions in the sea salt, further improving the salt production rate and purity.

[0015] The solar-powered refined salt production device of this invention is simple in structure, easy to operate, and low in cost. The entire device requires no complex design; concentrated seawater and sea salt solids containing a high concentration of sodium chloride can be obtained through a simple photothermal interface evaporation structure, and the extracted sea salt is then directly subjected to physical washing. Based on the differences in concentration and solubility among the various components of the sea salt, washing with concentrated seawater that is nearly saturated with sodium chloride can retain most of the sodium chloride in the sea salt, while effectively removing potassium, magnesium, and calcium impurities. This eliminates the need for chemical reaction precipitation steps, significantly simplifying the operation process and substantially reducing equipment investment and operation and maintenance costs.

[0016] This invention is energy-efficient and environmentally friendly. The entire process utilizes renewable solar energy, eliminating the need for additional fossil fuels and reducing energy consumption in traditional salt-making processes at the source. Simultaneously, it employs a physical washing method to refine crude salt, eliminating the need for additional chemical agents and preventing secondary pollution. This ensures the safety of the refined salt product while aligning with green and sustainable development principles, demonstrating significant environmental value.

[0017] The refined salt produced by this invention has high purity. Compared to sea salt, the refined salt produced by this device shows significantly better removal of potassium, magnesium, and calcium. The sodium-potassium ratio, sodium-magnesium ratio, and sodium-calcium ratio of the refined salt are all greater than the corresponding ion ratios calculated from the Codex Alimentarius Standard for Edible Salt (CODEX STAN 150-1985), the National Food Safety Standard for Edible Salt (GB721-2015), and the Standard for the Use of Food Additives (GB2760-2024). The calcium and magnesium content is far below the maximum mass fraction specified in Industrial Salt (GB / T5462-2015), and the sodium-lithium ratio is within the range of ion ratio values ​​collected from commercially available edible salt, achieving ideal refining results. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the concentration / salt extraction component of the present invention; Figure 3 This is a schematic diagram of the structure of the evaporator component of the present invention; Figure 4 This is a schematic diagram of the structure of the salt extraction evaporator component of the present invention; Figure 5 This is a schematic diagram of the structure of the salt-lifting plate component of the present invention; Figure 6 This is a schematic diagram of the structure of the stirring component of the present invention; Figure 7 This is a schematic diagram of the structure of the leakage channel of the present invention; Figure 8 This is an outdoor operation effect diagram of the solar-powered refined salt production device of the present invention. Figures 9(a) to 9(f) show the experimental results of various combinations of the concentration evaporator and salt extraction evaporator of the present invention; Figure 10 This is an ion analysis curve of refined salt produced by the solar-powered refined salt production device of the present invention and commercially available edible salt.

[0019] In the diagram: Concentration / Salt Extraction Component 1, Salt Extraction Plate 1-1, Salt Extraction Plate Fixing End 110, Salt Extraction Plate Salt-Carrying End 111, Heat Insulation Support Component 1-2, Concentration Evaporator 1-3, Trapezoidal Light Absorbing Layer 130, Trapezoidal Upper Photothermal Layer 131, Trapezoidal Lower Photothermal Layer 132, Narrow Water Transport Layer 133, Outer Wide Water Transport Layer 134, Inner Wide Water Transport Layer 135, Salt Extraction Evaporator 1-4, Salt Extraction Light Absorbing Layer 140, Salt Extraction Upper Photothermal Layer 141, Salt Extraction Lower Photothermal Layer 142, Salt Conducting Layer 143, Outer Water Transport Layer 144, Inner Water Transport Layer 145, Stirring Component 2, Power Supply 2-1, Motor Fixing Component 2-2, Rotating Rod 2-3, Motor 2-4, Stirring Rod 2-5, Stirring Blade 2-6, Slot 3, Slot Upper Frame 3-1, Slotted Mesh 3-2, Slot Bottom Frame 3-3, Limiting Rod 3-4, Water Tank 4. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are illustrative rather than limiting. In the description of the present invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not 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 the present invention. 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 indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise stated, "multiple" means two or more.

[0021] Inspired by the emerging photothermal interface evaporation technology, this invention proposes its application in refined salt production. Photothermal interface evaporation technology effectively absorbs solar energy and converts it into heat energy, confining this heat energy to the water-air interface to locally heat the water, resulting in highly efficient water evaporation. This low-carbon and environmentally friendly method requires no additional energy input, significantly reducing energy consumption. The physical washing method, based on the differences in concentration and solubility of various components in sea salt, uses concentrated seawater to physically agitate and wash the sea salt, effectively removing impurities such as potassium, magnesium, and calcium ions without the potential environmental pollution caused by complex chemical purification processes. Organically coupling these two technologies not only significantly reduces energy consumption but also greatly simplifies the refined salt production process, accelerating the production efficiency of thermal zero-carbon refined salt through efficient photothermal conversion. This novel refined salt production solution provides a highly efficient, economical, technically simple, and low-energy-consumption approach for the refined salt production field, and is expected to be widely applied and promoted in future refined salt production, driving the entire refined salt production industry towards a green and sustainable development.

[0022] like Figure 1 As shown, a solar-powered refined salt production device includes a salt concentration / extraction component 1, a stirring component 2, a trough 3, and a water tank 4. The salt concentration / extraction component 1 is located in the middle of the liquid surface of the water tank 4, the stirring component 2 is located on both sides of the liquid surface of the water tank 4, and a trough 3 is provided below each stirring component 2.

[0023] like Figure 2As shown, the concentration / salt extraction component 1 includes a salt extraction plate 1-1, a heat insulation support 1-2, a concentration evaporator 1-3, and a salt extraction evaporator 1-4. The two ends of the heat insulation support 1-2 are installed on the water tank 4. Multiple concentration evaporators 1-3 are arranged in the middle of the heat insulation support 1-2. Multiple salt extraction evaporators 1-4 are arranged on both sides of the concentration evaporators 1-3 and on the heat insulation support 1-2. The ratio of the number of concentration evaporators 1-3 to the number of salt extraction evaporators 1-4 is 1:1. The salt extraction plate 1-1 is arranged below the salt extraction evaporators 1-4. The trough 3 is located below the salt extraction plate 1-1.

[0024] like Figure 3 As shown, the concentrator 1-3 includes a trapezoidal light-absorbing layer 130, a trapezoidal upper photothermal layer 131, and a trapezoidal lower photothermal layer 132 arranged sequentially from top to bottom. The bottom two ends of the trapezoidal lower photothermal layer 132 are respectively connected to a narrow water conveying layer 133 that bends downwards to allow water to enter and an inner wide water conveying layer 135. The long bottom edge of the trapezoidal upper photothermal layer 131 is connected to an outer wide water conveying layer 134 that bends downwards to allow water to enter. The narrow water conveying layer 133, the inner wide water conveying layer 135, and the outer wide water conveying layer 134 are used to draw seawater from the lower water tank 4 to the trapezoidal light-absorbing layer 130 for evaporation. After evaporation, salt ions are transported from the inner wide water conveying layer. Layer 135 and the outer wide water conveyance layer 134 flow back to the water tank 4 towards the narrow water conveyance layer 133, thereby achieving continuous concentration of seawater. The trapezoidal light-absorbing layer 130, the trapezoidal upper photothermal layer 131, and the trapezoidal lower photothermal layer 132 are trapezoids with a short base: long base: height ratio of 1:3:2~3. The thickness of the trapezoid depends on the material itself. The width ratio of the wide water conveyance layer 134 to the narrow water conveyance layer 133 is 3:1. The multiple concentrators 1-3 are staggered trapezoids, with the short base and long base of adjacent trapezoids arranged alternately in the middle row, which can concentrate seawater to 10~24wt% concentrated seawater.

[0025] like Figure 4As shown, the salt extraction evaporator 1-4 includes a salt extraction light-absorbing layer 140, an upper salt extraction photothermal layer 141, and a lower salt extraction photothermal layer 142 arranged sequentially from top to bottom. The upper salt extraction photothermal layer 141, near the concentrator 1-3, is connected to an outer water conveying layer 144 that bends downwards to allow water to enter. The lower salt extraction photothermal layer 142, near the concentrator 1-3, is connected to an inner water conveying layer 145 that bends downwards to allow water to enter. The long side of the lower salt extraction photothermal layer 142, away from the concentrator 1-3, is connected to a salt-conducting layer 143 for extracting solid sea salt. The widths of the outer water conveying layer 144 and the inner water conveying layer 145 are the same as those of the salt extraction light-absorbing layer 140, the upper salt extraction photothermal layer 141, and the lower salt extraction photothermal layer 142. The widths of the long sides of the evaporators 1-3 are equal. The sides of the salt-extracting light-absorbing layer 140, the upper photothermal layer 141, and the lower photothermal layer 142 near the evaporator 1-3 are adjacent to and parallel to the bottom sides of the trapezoidal light-absorbing layer 130, the upper photothermal layer 131, and the lower photothermal layer 132. Their lengths are equal to or equal to the lengths of the long bottom sides of the trapezoidal light-absorbing layer 130, the upper photothermal layer 131, and the lower photothermal layer 132. The salt-conducting layer 143 is a trapezoid with a ratio of bottom side: long bottom side: height of 1:3:2~3. The long bottom side of the salt-conducting layer 143 is connected to the side of the lower photothermal layer 142 away from the concentrating evaporator 1-3 and has the same width. The salt-extracting evaporator 1-4 is located on each side of the concentrating evaporator 1-3, and can extract solid sea salt.

[0026] The salt extraction light-absorbing layer 140, the upper salt extraction photothermal layer 141, and the lower salt extraction photothermal layer 142 have the same shape. They are all rectangles with a length-to-width ratio of 3~4:2~3 or right-angled trapezoids with a short base: long base: height ratio of 3:4:2~3. The long side of the rectangle or the long base of the right-angled trapezoid is closer to the side of the evaporator 1-3.

[0027] The concentrator 1-3 and the salt extraction evaporator 1-4 are adjacent to each other along their long sides and are closely arranged. The special structural design allows seawater to be concentrated in the concentrator 1-4 in the middle of the device, and salt to be extracted in the salt extraction evaporators 1-4 at both ends, thereby achieving the effect of water-salt separation.

[0028] Furthermore, the trapezoidal light-absorbing layer 130 and the rectangular light-absorbing layer 140 are made of materials with broad-spectrum solar energy absorption capabilities for efficient photothermal conversion; in this embodiment, black modal fabric is selected. The upper trapezoidal photothermal layer 131, the lower trapezoidal photothermal layer 132, the narrow water-carrying layer 133, the inner wide water-carrying layer 135, and the outer wide water-carrying layer 134 are made of materials with strong hydrophilicity and flexibility; in this embodiment, coconut shell fabric is selected to provide efficient water supply for evaporation. The upper salt-extraction photothermal layer 141, the lower salt-extraction photothermal layer 142, the outer water-carrying layer 144, and the inner water-carrying layer 145 are made of materials with strong hydrophilicity and flexibility; in this embodiment, coconut shell fabric is selected. Using a fabric with strong hydrophilicity as the water-carrying material ensures efficient water supply during evaporation; furthermore, the microporous structure formed by the interlaced fibers of the fabric has the potential to reduce the enthalpy of water evaporation, further improving the efficiency of photothermal conversion.

[0029] like Figure 5 As shown, the salt-lifting plate 1-1 is bent at a certain angle to form a salt-lifting plate fixed end 110 and a salt-carrying end 111. The salt-lifting plate fixed end 110 is fixed below the lower photothermal layer 142 of the salt-lifting plate, and the salt-carrying end 111 is set below the salt-guiding layer 143 and its width is greater than the height of the trapezoidal salt-guiding layer 143.

[0030] like Figure 6 As shown, the stirring component 2 includes a power supply 2-1, a motor mounting component 2-2, a rotating rod 2-3, a motor 2-4, a stirring rod 2-5, and a stirring blade 2-6. The power supply 2-1 is fixedly mounted above the motor mounting component 2-2 and is electrically connected to the motor 2-4. The motor 2-4 is a single-output shaft motor, with its output shaft connected to the stirring rod 2-5 perpendicular to the liquid surface. The other end of the stirring rod 2-5 is equipped with a stirring blade 2-6 for stirring the concentrated seawater in the water tank 4. The rotating rod 2-3 passes through the lower part of the motor mounting component 2-2. The rotating rod 2-3 is connected to the pre-drilled hole in the water tank 4 body via a socket joint, allowing for quick installation and removal of the motor mounting component. Specifically, by inserting and removing the rotating rod 2-3, the motor mounting component 2-2 can be flexibly removed as needed. Furthermore, through mechanical design, the motor mounting component 2-2 can rotate upwards, i.e., flip outwards.

[0031] like Figure 7 As shown, the trough 3 includes an upper frame 3-1, a mesh 3-2, a bottom frame 3-3, and a limiting rod 3-4. The limiting rod 3-4 passes through the corresponding holes reserved in the upper frame 3-1, the mesh 3-2, and the bottom frame 3-3 from top to bottom, forming an integrated assembly through the connection and positioning. The stirring blade 2-6 is located inside the trough 3.

[0032] Furthermore, the length of the stirring rod 2-5 is slightly shorter than the distance from the lower surface of the motor fixing part 2-2 to the surface of the mesh 3-2; the blade shape of the stirring blade 2-6 is circular or rectangular, and the distance from the edge of the blade to the stirring rod 2-5 is controlled to be less than 5mm; the aperture of the mesh 3-2 is ≤0.15mm.

[0033] The solar-powered refined salt production method based on the aforementioned device includes the following steps: S1: Add seawater to be treated into the water tank 4, so that the narrow water conveying layer 133, the inner wide water conveying layer 135, the outer wide water conveying layer 134 of the evaporator 1-3, and the outer water conveying layer 144 and the inner water conveying layer 145 of the salt extraction evaporator 1-4 are immersed in seawater. S2: The device is naturally exposed to sunlight or simulated light source. The trapezoidal light-absorbing layer 130 of the concentrator 1-3 absorbs solar energy and converts it into heat energy, heating the upper trapezoidal photothermal layer 131 and the lower trapezoidal photothermal layer 132. Seawater is continuously adsorbed to the interface of the concentrator 1-3. The heat energy is confined to the evaporation interface to achieve local heating, and the seawater evaporates rapidly. Most of the salt ions are transported from bottom to top to the surface of the concentrator 1-3 under the action of capillary force through the inner wide water transport layer 135 and the outer wide water transport layer 134. The unidirectional flow drives the salt ions to flow back to the water tank 4 along the direction from the lower trapezoidal photothermal layer 132 to the narrow water transport layer 133, so that the seawater in the water tank 4 is gradually concentrated to 10~24wt%; S3: The seawater that is continuously concentrated in the water tank 4 is adsorbed to the evaporation interface by the outer water conveying layer 144 and the inner water conveying layer 145 of the salt extraction evaporator 1-4. The salt extraction light-absorbing layer 140 of the salt extraction evaporator 1-4 absorbs solar energy and converts it into heat energy, which heats the upper photothermal layer 141 and the lower photothermal layer 142 of the salt extraction. The seawater evaporates rapidly, and the salt ions flow in the direction of the salt guiding layer 143 and precipitate at the bottom of the salt guiding layer 143. They naturally adhere to the salt extraction plate 1-1, and the precipitated sea salt solids slide off the salt-carrying end 111 and fall into the trough 3. S4: When the seawater in tank 4 is concentrated and evaporated to 3 / 100-1 / 20 of its original volume, turn on the power supply 2-1 to supply power to motor 2-4. The motor drives the stirring rod 2-5 to rotate the stirring blade 2-6, stirring the concentrated seawater and sea salt in the trough 3. Utilizing the principle of physical washing, the concentrated seawater and sea salt are fully contacted through stirring. Based on the differences in solubility and concentration between sea salt components, impurities such as calcium, potassium, and magnesium ions in the sea salt are directly and physically removed. Moreover, under the current ratio of the concentration evaporator 1-3 and the salt extraction evaporator 1-4, when the device evaporates to meet the washing conditions, the remaining amount of concentrated brine matches the amount of crude salt extracted, reducing washing losses and ensuring the production rate of refined salt. S5: The refined salt obtained by physical washing is trapped by the mesh 3-2 of the trough 3. After stirring, the trough 3 is removed manually or by machine, and then dried to obtain solid refined salt that is easy to preserve.

[0034] like Figure 8 The image shown is an outdoor operation diagram of the solar-powered refined salt production device of the present invention.

[0035] As shown in Figure 9(a), the trapezoidal light-absorbing layer 130, the trapezoidal upper photothermal layer 131, and the trapezoidal lower photothermal layer 132 of combination 1 are trapezoids with a short base: long base: height ratio of 1:3:2. The salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142 have the same shape, all of which are rectangles with a length-to-width ratio of 3:2. The salt-conducting layer 143 is an isosceles trapezoid with a short base: long base: height ratio of 1:3:2. The long base of the trapezoidal light-absorbing layer 130, the trapezoidal upper photothermal layer 131, and the trapezoidal lower photothermal layer 132 is equal to and fits the long rectangular side of the salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142. The width of each water-conducting layer matches the dimensions of the connection points of the above structures. As shown in Figure 9(b), combination 2 consists of a trapezoidal light-absorbing layer 130, a trapezoidal upper photothermal layer 131, and a trapezoidal lower photothermal layer 132, which are trapezoids with a short base: long base: height ratio of 1:3:2. The salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142 have the same shape, all of which are rectangles with a length-to-width ratio of 4:2. The salt-conducting layer 143 is an isosceles trapezoid with a short base: long base: height ratio of 1:3:2. The sum of the long base and the short base of the trapezoidal light-absorbing layer 130, the trapezoidal upper photothermal layer 131, and the trapezoidal lower photothermal layer 132 is equal to the long side of the rectangle of the salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142 and they are placed in a matching manner. The width of each water-conducting layer matches the dimensions of the connection points of the above structures. As shown in Figure 9(c), combination 3 consists of a trapezoidal light-absorbing layer 130, a trapezoidal upper photothermal layer 131, and a trapezoidal lower photothermal layer 132, which are trapezoids with a short base: long base: height ratio of 1:3:2. The salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142 have the same shape, all being right-angled trapezoids with a short base: long base: height ratio of 3:4:2. The salt-conducting layer 143 is a right-angled trapezoid with a short base: long base: height ratio of 1:3:2. The sum of the long base and short base of the trapezoidal light-absorbing layer 130, the trapezoidal upper photothermal layer 131, and the trapezoidal lower photothermal layer 132 is equal to the long base of the salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142 and is placed in a matching manner. The width of each water-conducting layer matches the dimensions of the connection points of the above structures. As shown in Figure 9(d), combination 4 consists of a trapezoidal light-absorbing layer 130, a trapezoidal upper photothermal layer 131, and a trapezoidal lower photothermal layer 132, which are trapezoids with a short base: long base: height ratio of 1:3:2. The salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142 have the same shape, all being right-angled trapezoids with a short base: long base: height ratio of 3:4:2. The salt-conducting layer 143 is an isosceles trapezoid with a short base: long base: height ratio of 1:3:2. The sum of the long base and the short base of the trapezoidal light-absorbing layer 130, the trapezoidal upper photothermal layer 131, and the trapezoidal lower photothermal layer 132 is equal to the long base of the salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142 and is placed in a matching manner. The width of each water-conducting layer matches the connection of the above-mentioned structural dimensions. As shown in Figure 9(e), combination 5 consists of a trapezoidal light-absorbing layer 130, a trapezoidal upper photothermal layer 131, and a trapezoidal lower photothermal layer 132, which are trapezoids with a short base: long base: height ratio of 1:3:3. The salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142 have the same shape, all of which are rectangles with a length-to-width ratio of 3:2. The salt-conducting layer 143 is an isosceles trapezoid with a short base: long base: height ratio of 1:3:3. The long base of the trapezoidal light-absorbing layer 130, the trapezoidal upper photothermal layer 131, and the trapezoidal lower photothermal layer 132 is equal to and fits the long rectangular side of the salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142. The width of each water-conducting layer matches the dimensions of the connection points of the above structures. As shown in Figure 9(f), combination 6 consists of a trapezoidal light-absorbing layer 130, a trapezoidal upper photothermal layer 131, and a trapezoidal lower photothermal layer 132, which are trapezoids with a short base: long base: height ratio of 1:3:3. The salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142 have the same shape, all being right-angled trapezoids with a short base: long base: height ratio of 3:4:3. The salt-conducting layer 143 is an isosceles trapezoid with a short base: long base: height ratio of 1:3:3. The sum of the long base and short base of the trapezoidal light-absorbing layer 130, the trapezoidal upper photothermal layer 131, and the trapezoidal lower photothermal layer 132 is equal to and fits the long base of the salt-lifting light-absorbing layer 140, the salt-lifting upper photothermal layer 141, and the salt-lifting lower photothermal layer 142. The width of each water-conducting layer matches the dimensions of the connection points of the above structures.

[0036] Example 1 In this embodiment, a large water tank 4 is used as the base, and the other components are placed inside and on the water tank 4.

[0037] The trapezoidal light-absorbing layer 130, trapezoidal upper photothermal layer 131, and trapezoidal lower photothermal layer 132 of the evaporator 1-3 are viewed from above as isosceles trapezoids with the following dimensions: short base 1 cm, long base 3 cm, and height 2 cm. The trapezoidal upper photothermal layer 131 is placed on top of the trapezoidal lower photothermal layer 132, and the trapezoidal light-absorbing layer 130 is placed on top of the trapezoidal upper photothermal layer 131. The three parts are closely stacked.

[0038] The salt-conducting layer 143 is an isosceles trapezoid with the following dimensions: short base 1cm, long base 3cm, and height 2cm. The salt-lifting light-absorbing layer 140, the upper salt-lifting photothermal layer 141, and the lower salt-lifting photothermal layer 142 are rectangular, with a length of 3cm and a width of 2cm. The inner and outer wide water-conducting layers are both rectangular, with a length of 8cm and a width of 3cm. The upper salt-lifting photothermal layer is placed on top of the lower salt-lifting photothermal layer, and the salt-lifting light-absorbing layer is placed on top of the upper salt-lifting photothermal layer. The three components are closely stacked.

[0039] The thermal insulation support 1-2 used in this embodiment is 15 cm long, 10 cm wide, and 2 cm thick. Along the length of the water tank 4, the thermal insulation support 1-2 has the following structure: a 1 cm wide left slope, a 2 cm wide left long plate, a 1 cm wide left rectangular hole, a 2 cm wide middle long plate, a 1 cm wide right rectangular hole, a 2 cm wide right long plate, and a 1 cm wide right slope. The slope is designed to facilitate the installation of the salt-lifting plate 1-1.

[0040] The salt-lifting plate 1-1 is made of aluminum sheet and can be bent into two parts: a fixed end 110 and a salt-carrying end 111. The fixed end of the salt-lifting plate is 10 cm long and 2 cm wide, and the salt-lifting end is 10 cm long and 4 cm wide. The fixed end and the salt-lifting end of the salt-lifting plate form a 150° angle.

[0041] The evaporators 1-3 are horizontally mounted on a 2 cm wide central plate. Four evaporation components are mounted along the long side. When arranged, the sides of the evaporators 1-3 are closely connected and arranged in parallel and staggered manner, that is, the short bottom edge of the adjacent evaporators is connected to the long bottom edge.

[0042] The wide water delivery layer of the salt extraction evaporator 1-4 and the wide water delivery layer of the concentration unit are placed opposite each other and are tightly mounted on the left and right long plates of 2cm, with 2 on each of the left and right long plates.

[0043] The power supply 2-1 is fitted into the corresponding power supply slot of the motor mounting bracket 2-2, and a switch is installed. The motor 2-4 is tightly fitted into the hole on the motor mounting bracket 2-2, keeping the stirring rod 2-5 perpendicular to the motor mounting bracket 2-2, and one side of the stirring blade 2-6 is positioned above the trough 3 inside the water tank. When the power supply 2-1 is connected, the motor 2-4 of the stirrer begins to drive the stirring blade 2-6 to rotate at high speed.

[0044] In this embodiment, two troughs 3 are placed below the salt-lifting ends of the salt-lifting plates 1-1 on both sides. They are used to load coarse salt for physical washing and to filter and collect refined salt after washing. The limiting rod 3-4 passes through the bottom frame 3-3, the mesh 3-2, and the upper frame 3-1 of the trough from bottom to top, allowing for flexible assembly and disassembly of the troughs 3.

[0045] In this embodiment, the water tank initially contains 1 L of 3.5 wt% sea salt solution, and the concentration / salt extraction unit 1 is placed in the center of the water tank 4. During operation, the water level remains constant throughout the water tank 4. The coconut shell cloth has strong hydrophilicity, and the brine in the water tank 4 will wet the concentration evaporators 1-3 and the salt extraction evaporators 1-4.

[0046] Simulated illumination of 200 mW cm -2 Below, the light-absorbing layer absorbs solar heat, accelerating the evaporation rate at the interface of the photothermal layer. The brine supply to the concentrator 1-3 is unidirectional, with the macroscopic brine flow direction being: migrating from the wide water delivery layer through the trapezoidal region to the narrow water delivery layer. As the brine slowly moves across the horizontal surface of the concentrator 1-3, i.e., the photothermal layer, water evaporates and is lost. Thus, the brine concentration increases during unidirectional movement, returning to the water tank through the narrow water delivery layer, and this cycle repeats, continuously increasing the concentration of the salt solution in the water tank 4.

[0047] The brine migration in the salt extraction evaporator 1-4 is also unidirectional. The macroscopic brine flow direction is from the water supply layer to the trapezoidal salt guiding layer. As the brine moves across the surface of the salt extraction evaporator, it continuously concentrates during its migration towards the trapezoidal salt guiding layer due to evaporation. At the edge of the trapezoidal salt guiding layer, the brine is nearly saturated and brine aggregates. The high-concentration brine at the edge of the trapezoidal salt guiding layer loses water under natural evaporation conditions, precipitating coarse salt, which accumulates on the salt extraction plate 1-1. Under the action of gravity and thrust, the coarse salt accumulates and grows along the salt extraction end of the salt extraction plate 1-1 towards the periphery.

[0048] Towards the end of evaporation, the coarse salt falls into the trough 3 due to gravity or manual scraping. The trough 3 is connected to the brine in the water tank 4. When 30 mL of brine remains in the device, evaporation is stopped, and washing of the coarse salt begins. During washing, the stirrer 3 is turned on to ensure rapid and complete dissolution of the coarse salt. Because the sodium chloride concentration in the remaining brine in the water tank 4 is high and close to saturation, its ability to dissolve more sodium chloride in the coarse salt is limited. However, the brine still has a strong ability to dissolve calcium and magnesium salts. Therefore, washing can selectively dissolve impurities such as calcium, potassium, and magnesium ions in the coarse salt in the brine in the water tank 4. After stirring for 5 minutes, the motor is turned off, completing the washing process. The refined salt is collected by simple filtration using the filter tank 4, and then the filter tank 4 is placed in a drying oven to dry the refined salt.

[0049] In this embodiment, as shown in Table 1, the combined device 1 can achieve 2.30 kg. m -2 h -1 The evaporation rate allows for the final concentration of 3.5 wt% brine to 11.9 wt%, resulting in a refined salt production rate of 0.02 kg / kg. m -2 h -1Meanwhile, comparative elemental analysis of the refined salt produced by the device with raw sea salt solid and commercially available edible salt can scientifically verify the device's effectiveness in removing potassium, magnesium, and calcium, providing a scientific basis for applying this technology to edible salt production. 1 g each of refined salt, raw sea salt, and various types of commercially available edible salt were prepared into 10 ppm detection solutions with pure water. Elemental analysis of the salt solutions was performed using an inductively coupled plasma atomic absorption spectrometer. The analysis results are shown in Tables 2 and 3. Figure 10 As shown. The sodium-potassium ratio, sodium-magnesium ratio, sodium-calcium ratio, and sodium-lithium ratio of the refined salt produced by apparatus 1 are 59.90, 429.59, 366.36, and 8880.37, respectively, which are 1.37, 1.99, 5.15, and 26.39 times higher than those of sea salt. The sodium refining and potassium, magnesium, and calcium removal effects are obvious. Moreover, compared with commercially available edible salt, the sodium-potassium ratio, sodium-magnesium ratio, sodium-calcium ratio, and sodium-lithium ratio of the refined salt are all within the range of ion ratio values ​​of the collected commercially available edible salt. According to the Codex Alimentarius Standard for Edible Salt (CODEX STAN 150-1985) and the National Food Safety Standard for Edible Salt (GB721-2015), the sodium chloride content should be 97 g / 100 g (dry basis). Assuming the remaining component is a single element, such as pure potassium chloride, calcium chloride, or magnesium chloride, it can be reasonably estimated that the sodium-potassium ratio, sodium-magnesium ratio, and sodium-calcium ratio in edible salt should be above 24.290, 35.279, and 50.313, respectively. The corresponding ion ratios of the refined salt produced by combination 1 are all greater than the standard requirements. The National Food Safety Standard for the Use of Food Additives (GB2760-2024) stipulates that the amount of potassium chloride added should not exceed 350 g / kg, i.e., the mass fraction should not exceed 35%. The potassium chloride mass fraction of the refined salt produced by combination 1 in this device is 0.92%, which is far below the range specified in the standard. The standard GB / T5462-2015 for industrial salt stipulates that the total calcium and magnesium content per 100.00 g of industrial salt should be between 0.25 g and 0.70 g (on a wet basis). After simple conversion, the standard specifies a calcium and magnesium ratio of 0.25% to 0.70%. The total calcium and magnesium content in the refined salt produced by combination 1 is 0.15%, which is lower than the minimum limit of the standard. Furthermore, the elemental analysis of the refined salt produced by other combinations is shown in Tables 2 and 3. Figure 10 This is reflected in the data, and the ion ratios are all within the range of the ion ratio values ​​of the commercially available edible salt collected. The total calcium and magnesium content in the refined salt per unit mass is less than 0.70%.

[0050] Table 1. Experimental performance of different combinations of the present invention under the same test conditions. Table 2. Relative proportions of major metal salt ions in the refined salt prepared by this invention and commercially available refined salt samples under the same testing conditions. Table 3. Sodium ion content of refined salt prepared by this invention and commercially available refined salt samples under the same testing conditions. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and all of these should be considered within the scope of protection of the present invention.

Claims

1. A solar-powered refined salt production device, characterized in that, It includes a concentration / salt extraction component (1), a stirring component (2), a trough (3), and a water tank (4). The concentration / salt extraction component (1) is located in the middle of the liquid surface of the water tank (4), the stirring component (2) is located on both sides of the liquid surface of the water tank (4), and a trough (3) is provided below the stirring component (2). The concentration / salt extraction component (1) includes a salt extraction plate (1-1), a heat insulation support (1-2), a concentration evaporator (1-3), and a salt extraction evaporator (1-4). The two ends of the heat insulation support (1-2) are installed on the water tank (4). Multiple concentration evaporators (1-3) are arranged in the middle of the heat insulation support (1-2). Multiple salt extraction evaporators (1-4) are arranged on both sides of the concentration evaporators (1-3) and on the heat insulation support (1-2). The salt extraction plate (1-1) is arranged below the salt extraction evaporator (1-4). The trough (3) is located below the salt extraction plate (1-1).

2. The solar-powered refined salt production device according to claim 1, characterized in that, The evaporator (1-3) comprises, from top to bottom, a trapezoidal light-absorbing layer (130), a trapezoidal upper photothermal layer (131), and a trapezoidal lower photothermal layer (132). The bottom edges of the lower trapezoidal photothermal layer (132) are respectively connected to a narrow water delivery layer (133) that bends downwards to allow water to enter, and an inner wide water delivery layer (135). The long bottom edge of the upper trapezoidal photothermal layer (131) is connected to an outer wide water delivery layer (134) that bends downwards to allow water to enter. The narrow water delivery layer (133), the inner wide water delivery layer (135), and the outer wide water delivery layer (134) are connected by… Seawater in the lower tank (4) is drawn into the trapezoidal light-absorbing layer (130) for evaporation. After evaporation, salt ions flow back into the tank (4) from the inner wide water transport layer (135) and the outer wide water transport layer (134) towards the narrow water transport layer (133), thereby achieving continuous concentration of seawater. The trapezoidal light-absorbing layer (130), the upper trapezoidal photothermal layer (131), and the lower trapezoidal photothermal layer (132) are all trapezoids with a short base: long base: height ratio of 1:3:2~3. The multiple concentration evaporators (1-3) are staggered and spliced ​​in trapezoidal shape, with the short base connected to the long base in an alternating arrangement.

3. The solar-powered refined salt production device according to claim 2, characterized in that, The salt extraction evaporator (1-4) includes, from top to bottom, a salt extraction light-absorbing layer (140), an upper salt extraction photothermal layer (141), and a lower salt extraction photothermal layer (142). The upper salt extraction photothermal layer (141) is connected to an outer water conveying layer (144) that bends downwards into the water at one end near the concentrator (1-3). The lower salt extraction photothermal layer (142) is connected to an inner water conveying layer (145) that bends downwards into the water at one end near the concentrator (1-3), and a salt-conducting layer (143) at the end away from the concentrator (1-3), for extracting solid sea salt. The salt extraction light-absorbing layer (140)... The sides of the upper and lower photothermal layers (141 and 142) near the evaporator (1-3) are arranged parallel to the bottom sides of the trapezoidal light-absorbing layer (130), the upper and lower photothermal layers (131 and 132), and the length is the length of the long bottom side of the trapezoidal light-absorbing layer (130), the upper and lower photothermal layers (131 and 132) or the sum of the long and short bottom sides. The lower photothermal layer (142) is connected to the long bottom side of the salt-conducting layer (143), and the salt-conducting layer (143) is a trapezoid with a short bottom side: long bottom side: height ratio of 1:3:2~3.

4. The solar-powered refined salt production apparatus according to claim 3, characterized in that, The salt extraction light-absorbing layer (140), the upper salt extraction photothermal layer (141), and the lower salt extraction photothermal layer (142) have the same shape, and are all rectangles or right trapezoids with a length-to-width ratio of 3~4:2~3 or a short base: long base: height ratio of 3:4:2~3; the long side of the rectangle or the long base of the right trapezoid is close to the side of the evaporator (1-3).

5. The solar-powered refined salt production apparatus according to claim 3, characterized in that, The salt-lifting plate (1-1) is bent at 100~170° to form a fixed end (110) and a salt-carrying end (111). The fixed end (110) is fixed below the lower photothermal layer (142) of the salt-lifting plate, and the salt-carrying end (111) is located below the salt-guiding layer (143) and its width is greater than the height of the trapezoidal salt-guiding layer (143).

6. The solar-powered refined salt production apparatus according to claim 1, characterized in that, The stirring component (2) includes a power source (2-1), a motor fixing component (2-2), a rotating rod (2-3), a motor (2-4), a stirring rod (2-5), and a stirring blade (2-6). The power source (2-1) is fixedly installed above the motor fixing component (2-2), and the power source (2-1) is electrically connected to the motor (2-4). The output shaft of the motor (2-4) is connected to the stirring rod (2-5) perpendicular to the liquid surface. The other end of the stirring rod (2-5) is equipped with a stirring blade (2-6) for stirring the concentrated seawater in the water tank (4). The rotating rod (2-3) is installed through the motor fixing component (2-2) below. The rotating rod (2-3) is connected to the reserved hole of the water tank (4) body by a socket connection and is arranged through the water tank (4) body to realize the quick installation and disassembly of the motor fixing component.

7. The solar-powered refined salt production apparatus according to claim 6, characterized in that, The trough (3) includes an upper frame (3-1), a mesh (3-2), a bottom frame (3-3), and a limiting rod (3-4). The limiting rod (3-4) passes through the corresponding holes reserved in the upper frame (3-1), mesh (3-2), and bottom frame (3-3) of the trough from top to bottom, and is connected and positioned to form an integrated assembly. The stirring blade (2-6) is located inside the trough (3).

8. The solar-powered refined salt production apparatus according to claim 7, characterized in that, The length of the stirring rod (2-5) is shorter than the distance from the lower surface of the motor fixing part (2-2) to the surface of the screen (3-2); the blade shape of the stirring blade (2-6) is circular or rectangular, and the distance from the edge of the blade to the stirring rod (2-5) is controlled to be less than 5 mm; the aperture of the screen (3-2) is ≤0.15 mm.

9. The solar-powered refined salt production apparatus according to claim 1, characterized in that, The ratio of the number of concentration evaporators (1-3) to the number of salt extraction evaporators (1-4) is 1:

1.

10. A method for producing solar-powered refined salt based on the apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Add the seawater to be treated into the water tank (4) so ​​that the narrow water conveying layer (133), the inner wide water conveying layer (135), the outer wide water conveying layer (134) of the concentrator (1-3), and the outer water conveying layer (144) and the inner water conveying layer (145) of the salt extraction evaporator (1-4) are immersed in the seawater; S2: Allow the device to be naturally exposed to sunlight or simulated light source. The trapezoidal light-absorbing layer (130) of the concentrator (1-3) absorbs solar energy and converts it into heat energy, heating the upper trapezoidal photothermal layer (131) and the lower trapezoidal photothermal layer (132). Seawater is continuously adsorbed to the interface of the concentrator (1-3). The heat energy is limited to the evaporation interface to achieve local heating. The seawater evaporates rapidly. Under the action of capillary force, salt ions are transported from bottom to top to the surface of the concentrator (1-3) through the inner wide water transport layer (135) and the outer wide water transport layer (134). The unidirectional flow drives the salt ions to flow back to the water tank (4) along the direction from the lower trapezoidal photothermal layer (132) to the narrow water transport layer (133), so that the seawater in the water tank (4) is gradually concentrated to 10~24wt%; S3: The seawater that is continuously concentrated in the water tank (4) is adsorbed to the evaporation interface by the outer water conveying layer (144) and the inner water conveying layer (145) of the salt extraction evaporator (1-4). The salt extraction light-absorbing layer (140) of the salt extraction evaporator (1-4) absorbs solar energy and converts it into heat energy, which heats the upper light-thermal layer (141) and the lower light-thermal layer (142) of the salt extraction. The seawater evaporates rapidly, and the salt ions flow in the direction of the salt guide layer (143) and precipitate at the bottom of the salt guide layer (143). They naturally adhere to the salt extraction plate (1-1), and the precipitated sea salt solids slide down on the salt-carrying end (111) and fall into the trough (3). S4: When the seawater in the tank (4) is concentrated and evaporated to 3 / 100-1 / 20 of its original volume, turn on the power supply (2-1) to supply power to the motor (2-4). The motor drives the stirring rod (2-5) to rotate the stirring blade (2-6) and stir the concentrated seawater and sea salt solid in the trough (3). Using the principle of physical washing, the concentrated seawater and sea salt solid are fully contacted by stirring. Based on the difference in concentration and solubility of each component of sea salt, most of the impurities such as potassium, magnesium, and calcium ions in sea salt are directly removed by physical means. S5: The refined salt obtained after physical washing in step S4 is trapped by the sieve (3-2) of the sieve (3). After stirring, the sieve (3) is removed and dried to obtain solid refined salt.

Images