Spiral progressive salt pan controllable salifying structure and salt pan controllable salifying method

Abstract

The invention discloses a spiral progressive type salt pan controllable salt forming structure and a salt pan controllable salt forming method. The salt forming structure comprises brine flow channels arranged in a spiral pattern and a temperature control device, the peripheral area is a first salt production area for separating out first salt, and the central area is a second salt production area for separating out second salt; the economic value of the first salt is lower than that of the second salt; the temperature control device is arranged in the central area. Through the design of a salt pan space structure, two different salt production areas are distinguished by utilizing a spiral structure from outside to inside, and important salt precipitation nodes are concentrated in a very small central area space, so that the brine temperature, convection and other salt precipitation conditions in the area can be manually controlled at low cost; the large-scale controllable salt formation according to the phase chemical salt formation theory has possibility; the brine forms salt in the flowing process, different salt components can be prevented from being different in spatial distribution of the brine flow channel according to the salt separation sequence, and accurate salt product obtaining is easier.

Description

Technical Field

[0001] This invention belongs to the field of salt field harvesting technology, specifically relating to a spiral progressive controllable salt formation structure and a controllable salt formation method for salt fields. Background Technology

[0002] Traditional salt-forming processes in salt fields are often limited by the structure of the salt fields, making it impossible to carry out refined designs. Among them, square-shaped salt fields are the most mainstream.

[0003] It can be said that the design of this salt pan structure has remained unchanged since ancient times. With the continuous development of the modern salt lake industry, the scale of production has expanded dramatically, from the traditional few square kilometers to hundreds of square kilometers. Within such a large area, the climate varies greatly in different regions of the salt pan, and the composition of the brine differs significantly with spatial distribution.

[0004] Therefore, the phase chemical salt-forming theory based on precise condition control is difficult to apply practically to the salt-forming process of salt fields. It can only be used to explain certain local salt-forming phenomena and cannot be used to solve practical problems. Meanwhile, traditional salt field production processes do indeed face many technical challenges due to the uncontrollable environmental and brine conditions. In the salt field mineralization process, especially in the industrial-scale development and utilization of salt lakes, a series of specific salt-forming difficulties often exist. These difficulties not only affect resource development efficiency but also relate to the sustainable utilization of brine resources.

[0005] The mineralization of salt lake brine mainly relies on natural evaporation and concentration. During evaporation, the reduction of water and the increase in solution ion concentration lead to the formation of a series of salt precipitates. The salt formation sequence and mineral co-occurrence pattern are strictly controlled by the phase equilibrium and solubility laws under temperature-composition conditions. However, in traditional salt fields, brine temperature fluctuates with changes in air temperature, making the salt precipitation pattern complex and unpredictable. The salt precipitation stages in traditional salt fields are not finely segmented, resulting in the coexistence of solid phases precipitated in the early stages and later stages, leading to solid phase re-dissolution and inter-phase transformation, further complicating the complexity of the precipitated species and making the separation and purification of target salts more difficult. Salt field evaporation depends on high temperature and low humidity, but some salt lakes are located in high-altitude areas with large diurnal temperature variations and highly intermittent evaporation processes, resulting in uneven crystal quality. With the support of energy storage and temperature control infrastructure, the salt precipitation process can become more continuous and simpler.

[0006] The ancient structure of traditional salt fields is unsuitable for the development of modern salt lake industries and is not conducive to the integration of new scientific and technological innovations. Therefore, it is urgent to design a modern salt field production process. Summary of the Invention

[0007] The main objective of this invention is to provide a spiral progressive controlled salt formation structure and a controlled salt formation method for salt fields, so as to overcome the shortcomings of the prior art.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a spiral progressive salt field controllable salt formation structure, which includes brine channels arranged in a spiral pattern and a temperature control device. The outer peripheral area of ​​the spiral pattern is a first salt production area for the precipitation of a first salt, and the central area of ​​the spiral pattern is a second salt production area for the precipitation of a second salt. The economic value of the first salt is lower than that of the second salt.

[0010] The temperature control device is located in the central area and is used to precisely regulate the temperature of the brine in the central area.

[0011] Secondly, the present invention also provides a method for controllable salt formation in salt fields, comprising:

[0012] The brine is allowed to flow into the spiral-progressive salt field controllable salt formation structure and flow along the direction of the brine flow channel. During the flow, the water in the brine evaporates, the first salt is precipitated in the outer periphery of the spiral pattern, and the second salt is precipitated in the central area of ​​the spiral pattern.

[0013] In this case, the temperature of the brine in the central region is controlled by artificial intervention.

[0014] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0015] This invention utilizes a spatial structure design for salt fields, employing a spiral structure from the outside in to distinguish two different salt-producing areas. It concentrates important salt-forming nodes within a very small central area, which facilitates low-cost artificial control of brine temperature and convection conditions in this area. This makes large-scale, controllable salt formation based on phase chemical salt formation theory possible. Simultaneously, the brine forms salt during its flow, preventing different salt components from exhibiting variations in spatial distribution along the brine flow channel according to their salt formation sequence, thus making it easier to accurately obtain salt products.

[0016] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a salt field structure provided in a typical embodiment of this application;

[0019] Figure 2 This is a schematic diagram of a dissolution phase diagram provided in a typical embodiment of this application;

[0020] Figure 3 This is a schematic diagram of a staged salt precipitation path provided in a typical embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the dissolution phase diagram provided in Embodiment 1 of this application;

[0022] Figure 5 This is a schematic diagram of the staged salt precipitation path provided in Embodiment 1 of this application;

[0023] Figure 6 This is a schematic diagram of the dissolution phase diagram provided in Embodiment 2 of this application;

[0024] Figure 7 This is a schematic diagram of the staged salt precipitation path provided in Embodiment 2 of this application;

[0025] Figure 8 This is a schematic diagram of the dissolution phase diagram provided in Embodiment 3 of this application;

[0026] Figure 9 This is a schematic diagram of the staged salt precipitation path provided in Embodiment 3 of this application;

[0027] Figure 10 This is a schematic diagram of the dissolution phase diagram provided in Embodiment 4 of this application;

[0028] Figure 11 This is a schematic diagram of the staged salt precipitation path provided in Embodiment 4 of this application;

[0029] Figure 12 This is a schematic diagram of the dissolution phase diagram provided in Embodiment 5 of this application;

[0030] Figure 13 This is a schematic diagram of the staged salt precipitation path provided in Embodiment 5 of this application;

[0031] Figure 14This is a schematic diagram of the dissolution phase diagram provided in Embodiment 6 of this application;

[0032] Figure 15 This is a schematic diagram of the staged salt precipitation path provided in Embodiment 6 of this application. Detailed Implementation

[0033] As mentioned above, traditional salt pans are widely distributed, with highly uneven brine concentrations, and external conditions such as climate also exhibit significant spatial variations. In essence, traditional salt pans function as a massive reactor with highly uneven field influences and internal material distribution. Solution-phase chemical salt formation theory is very effective for controlled salt formation, but it relies on the premise of uniform solution material distribution and controllable field effects. This undoubtedly requires sophisticated, artificially controlled methods for convection and temperature regulation, which are extremely difficult to implement in the vast areas of traditional salt pans.

[0034] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0035] 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 therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0036] The present invention discloses a spiral progressive salt-forming structure for salt fields, which includes brine channels arranged in a spiral pattern and a temperature control device. The outer periphery of the spiral pattern is a first salt-producing area for the precipitation of a first salt, and the central area of ​​the spiral pattern is a second salt-producing area for the precipitation of a second salt. The economic value of the first salt is lower than that of the second salt.

[0037] The temperature control device is located in the central area to precisely regulate the temperature of the brine in the central area, while the brine in the outer area can rely on natural conditions to evaporate and precipitate salt without the need for artificial external heating sources or other intervention measures.

[0038] In some implementations, the brine is concentrated through evaporation:

[0039] Scenario 1: When the first salt precipitates in the brine earlier than the second salt, the outermost ring of the spiral pattern is provided with a brine inlet, which is connected to the brine flow channel; a brine pump is provided at the center of the spiral pattern to extract the remaining brine after concentration and salt precipitation.

[0040] Scenario 2: When the first salt precipitates out of the brine later than the second salt, a brine pump is provided on the outermost ring of the spiral pattern; a brine inlet is provided at the center of the spiral pattern.

[0041] Please see details. Figure 1 As shown, the salt pan structure of this invention employs a spiral progressive design. Taking the above scenario one as an example, brine is supplied from an external brine channel to the outer ring of the salt pan. The brine gradually flows slowly towards the inner ring via a fixed spiral path, evaporating simultaneously during this process, continuously increasing in concentration and crystallizing.

[0042] Crystallized products remain along the flow path, forming a segmented spatial distribution. Compared to traditional salt fields, it is easier to distinguish and obtain products at different stages through spatial segmentation control. This is beneficial for improving product purity in salt lake production and for more precise control of salt precipitation nodes at each stage. For example, in sulfate-type salt lakes, different salt products can be accurately obtained. Sulfate-type salt lakes exhibit behaviors such as double salting, precipitation, and transformation during the evaporation and precipitation stage, which not only slows down the precipitation process to some extent but also causes the target component to precipitate in the form of double salts, resulting in a lower yield. By precisely controlling the salt precipitation nodes at each stage and adjusting the process, timely separation of salt minerals can be achieved, reducing the loss of target components to some extent. Similarly, in chloride-type salt lakes, the precise node for entering the potassium salt stage can be obtained, avoiding the accumulation of large amounts of potassium salt. In the typical salt formation process of salt lake brine, the lower-value sodium salt precipitates in the initial stage. The spiral-progressive salt field design distributes the precipitation of these low-value-added salts in the outer ring. As the brine flows into the inner ring, various high-value-added potassium and lithium salts also begin to precipitate. Precise control is required to obtain the target product.

[0043] In the theory of phase chemical salt formation, the control of factors such as temperature and concentration is a prerequisite for accurately obtaining the corresponding salts. In the spiral-progressive salt field involved in this invention, spatial design concentrates the precipitation of these high-value potassium salts in a smaller inner area. This makes it possible to artificially control conditions such as temperature and convection, allowing the brine to reach the set temperature and achieve a very good uniform concentration distribution, which is highly beneficial for the precise collection of high-value salts. In traditional salt fields, due to limitations in process cost and technical feasibility, such artificial control is unimaginable in salt fields that cover tens or hundreds of square kilometers. Therefore, the phase chemical salt formation theory, which is traditionally considered impractical for salt field production, truly finds its application in the spiral-progressive salt field design provided by this invention.

[0044] In summary, the spiral-progressive salt pan design provided by this invention spatially concentrates the salt precipitation stage of high-value-added potassium and lithium salts into a very small area, only one-tenth to one-hundredth the size of a traditional salt pan. This makes modern artificial temperature and convection control methods feasible in salt pans. Simultaneously, the brine in the spiral-progressive salt pan undergoes salt precipitation during its flow, giving the salt precipitation distribution not only temporal attributes but also spatial attributes. The precipitated salts are distributed in segments along the spiral salt pan structure, enabling precise acquisition of the target product through spatially segmented salt harvesting.

[0045] It should be noted that the above-described specific embodiments are merely representative embodiments among the many feasible embodiments of the present invention, and not all embodiments. Figure 1 In this paper, a circular spiral structure is used as an example, but this does not mean that the salt field structure provided by this invention is limited to this shape. Usually, it can be planned according to the geographical environment of the site. For example, there may be triangular spiral patterns, hexagonal spiral patterns, or square spiral patterns (such square patterns are more suitable for multiple independent salt fields to be spliced ​​together to form an industrial cluster). Even irregular spiral patterns may appear due to terrain limitations. As long as the basic principles and functions disclosed above are met, they can all be used as implementation methods of this invention.

[0046] Furthermore, although the present invention uses a typical flow direction from the outside to the inside as a representative example, it is based on the fundamental idea provided by the present invention and the feasible methods are not limited to this. For some possible brine components, the high-value salts that require precise temperature control may be the first (or earlier) to precipitate. Therefore, in this case, the method of central water intake and peripheral water pumping can be adjusted to perform spiral salt precipitation. This method also utilizes the basic idea disclosed in the present invention and is also within the feasible scope of the present invention.

[0047] Regarding the specific structure, in some implementation schemes, the brine channel is formed by dams set on both sides, and the dams are mixed with phase change energy storage materials.

[0048] In some implementations, the phase change energy storage material comprises a single inorganic salt system or a hydrated salt eutectic system;

[0049] The single inorganic salt system includes a phase change inorganic salt and an additive. The phase change inorganic salt includes sodium sulfate decahydrate or calcium chloride hexahydrate. The additive includes any one or a combination of two or more of xanthan gum, expanded graphite, and sodium hexametaphosphate.

[0050] The hydrated salt eutectic system includes any one of the following: sodium sulfate-sodium chloride-ammonium chloride eutectic system and magnesium chloride-sodium nitrate-sodium nitrite-water eutectic system.

[0051] In the above embodiments, the dam design containing hydrated salt phase change energy storage materials can effectively buffer temperature changes caused by diurnal temperature variations. The bottom insulation material can also reduce heat loss, lowering the overall energy demand during temperature control. Subsequently, the brine can be heated via bottom heating pipes, allowing it to be maintained at a constant temperature in stages according to the needs of phased salt precipitation. Of course, the specific heating methods are not limited to pipe heating; methods such as embedding electric heating tape in the pool are also possible.

[0052] In some embodiments, the salt field structure further includes an extraction device comprising a walking module and a digging module. The walking module travels in the opposite direction of the brine channel using the dam. The digging module is fixedly connected to the walking module and has a digging robotic arm capable of extending into the brine channel to transfer salt precipitated in the brine channel to the outside of the brine channel.

[0053] In some embodiments, the temperature control device includes insulation material laid at the bottom of the central area and heating pipes disposed above the insulation material, the heating pipes being capable of carrying a heat medium.

[0054] As an application of the aforementioned salt field structure, this embodiment of the invention also provides a method for controlled salt formation in salt fields, which includes the following steps:

[0055] The brine is allowed to flow into the spiral-progressive salt field controllable salt formation structure and flow along the direction of the brine flow channel. During the flow, the water in the brine evaporates, the first salt is precipitated in the outer periphery of the spiral pattern, and the second salt is precipitated in the central area of ​​the spiral pattern.

[0056] In this case, the temperature of the brine in the central region is controlled by artificial intervention.

[0057] In some implementation schemes, the controlled salt formation method in the salt field specifically includes the following steps:

[0058] Based on the composition information of the brine, the evaporation route is calculated and planned using the solubility phase diagram;

[0059] Based on the evaporation route, a staged salt precipitation path is obtained;

[0060] Based on the described phased salt precipitation path, the target temperature of the central region is adjusted.

[0061] In some implementations, the brine is derived from salt lake brine.

[0062] In some embodiments, the flow rate of the brine in the brine channel is 0.5 m-100 m / day.

[0063] As a typical application example of the above technical solution, an exemplary process for salt precipitation using the salt field structure provided by the present invention includes:

[0064] Step 1: The salt field of this invention has a spiral progressive structure. Salt lake brine flows into the outer ring of the structure and salt is separated during the slow flow. The brine flow rate is controlled by the inlet gate of the outer ring and the liquid extraction speed of the water pump in the inner ring for taking old brine, and is between 0.5 m / day and 100 m / day.

[0065] Step 2: In the construction of the dam of the spiral-progressive salt field, hydrated salt phase change energy storage materials will be incorporated to absorb heat during the day and release heat at night, so as to alleviate the huge diurnal temperature difference in the salt lake area and make the temperature of the salt field more controllable. The components of the phase change energy storage material can be a single inorganic salt or a hydrated salt eutectic system. The single inorganic salt system includes sodium sulfate decahydrate and calcium chloride hexahydrate, with the main salt component accounting for 30% to 80%, and one or more of xanthan gum, expanded graphite and sodium hexametaphosphate can be added. The hydrated salt eutectic system includes: (1) sodium sulfate-sodium chloride-ammonium chloride eutectic system, in which the mass percentage of sulfuric acid is between 50% and 80%, the mass percentage of sodium chloride is between 15% and 5%, and the remaining component is ammonium chloride. (2) Magnesium chloride-sodium nitrate-sodium nitrite-water eutectic system, with the following component contents: magnesium chloride mass percentage between 20% and 60%, sodium nitrate mass percentage between 40% and 35%, water mass percentage between 0.5% and 3%, and the remaining component being sodium nitrite.

[0066] Step 3: The inner ring of the spiral-type salt field, designed for precise salt formation, is equipped with a temperature control device. First, insulation material is laid at the bottom of the salt pan. This material can be plastic foam, rock wool board, or aluminum magnesium silicate material to prevent heat loss. Above the insulation material, a connected heating pipe is installed. The heating pipe is made of high-temperature resistant and aging-resistant plastic, and carries hot water or steam internally. Its surface has an anti-salt-forming effect. Based on the solution phase diagram and the needs of staged salt precipitation, the brine temperature is controlled between 0℃ and 50℃.

[0067] Step 4: Taking sulfate subtype salt lakes as an example, their main component is Na. + K + Mg 2+ Cl – SO4 2– The temperature is between 0℃ and 50℃, following Figure 2 The evaporation path shown in the phase diagram precipitates products in stages, as follows: Figure 3 As shown.

[0068] Step 5: Based on production needs, a specially designed forklift is used. This forklift's wheels can travel on the embankment, and its bucket can reach the bottom of the pool to remove the salt products, dry them, and then send them to the workshop for further processing. The old brine, which does not require further refining in the inner ring of the spiral-progressive salt field, is transported downstream to the workshop for processing via pipelines and pumps.

[0069] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0070] Example 1

[0071] The salt field used in this embodiment has a spiral-progressive structure. Salt lake brine flows into the outer ring of this structure, undergoing salt precipitation during its slow flow. The brine flow rate is controlled at 0.5 m / day by the inlet gate in the outer ring and the pump speed for collecting old brine in the inner ring. Hydrated salt phase change energy storage materials are incorporated during dam construction. This is a single inorganic salt system, including sodium sulfate decahydrate, with the main salt component accounting for 30% by mass. Xanthan gum, expanded graphite, and sodium hexametaphosphate are also added, accounting for 70% by mass. Insulation material is laid at the bottom of the salt field, which can be plastic foam, rock wool board, or aluminum magnesium silicate material. A connected heating pipe is installed above the insulation material. The heating pipe is made of high-temperature resistant and aging-resistant plastic, carries hot water internally, and has an anti-salt-forming surface. The raw material processed by this salt field is sodium sulfate subtype salt lake brine, the main component of which is Li. + Na + K + Cl – and SO4 2– Segmented control is implemented, with temperature maintained at 0℃ throughout the entire process. The evaporation phase diagram is as follows: Figure 4 As shown, the products at each stage of brine evaporation are as follows: Figure 5 As shown.

[0072] Based on production needs, specially designed forklifts are used. These forklifts have wheels that can travel on the embankment, and their buckets can reach the bottom of the pools to remove salt products, dry them, and then send them to the workshop for further processing. The old brine, which does not require further refining in the inner ring of the spiral-progressive salt pan, is transported downstream to the processing workshop via pipelines and pumps. The brine evaporation process is controlled at 0℃ throughout, resulting in lithium-rich brine containing Li... + The content reached 6.57%, while Li + The yield was significantly better than that of room temperature evaporation (16.64%), reaching 72.5%.

[0073] Example 2

[0074] The salt field used in this embodiment has a spiral-progressive structure. Salt lake brine flows into the outer ring of this structure, undergoing salt precipitation during its slow flow. The brine flow rate is controlled by the outer ring inlet gate and the pump speed for extracting old brine in the inner ring, at 1 m / day. Hydrated salt phase change energy storage materials are incorporated during dam construction. This is a single inorganic salt system, including calcium chloride hexahydrate, with the main salt component accounting for 80% by mass. Expanded graphite and sodium hexametaphosphate are also added, accounting for the remaining 20% ​​by mass. Insulation material, specifically plastic foam board, is laid at the bottom of the salt field. A connected heating pipe is installed above the insulation material. The heating pipe is made of high-temperature resistant and aging-resistant plastic, carries hot water internally, and has an anti-salt-forming surface. The raw material processed by this salt field is sodium sulfate subtype salt lake brine, the main component of which is Li. + Na + K + Cl – and SO4 2– Segmented control is implemented, with temperature maintained at 50℃ throughout the entire process. The evaporation phase diagram is as follows. Figure 6 As shown, the products at each stage of brine evaporation are as follows: Figure 7 As shown.

[0075] Based on production needs, specially designed forklifts are used. These forklifts have wheels that can travel on the embankment, and their buckets can reach the bottom of the pools to remove salt products, dry them, and then send them to the workshop for further processing. The old brine, which does not require further refining in the inner ring of the spiral-progressive salt pan, is transported downstream to the processing workshop via pipelines and pumps. The temperature is controlled at 50℃ throughout the entire process. The lithium-rich brine obtained during the brine evaporation and crystallization process contains Li... + The content was higher than 0℃ throughout the entire temperature control process, reaching 7.56%, Li + Although the yield (44.83%) is not as high as that of evaporation at 0℃ throughout the entire process (72.5%), it is still much higher than that of evaporation at room temperature (16.64%), and the evaporation rate is fast, which greatly shortens the production cycle.

[0076] Example 3

[0077] The salt field used in this embodiment has a spiral progressive structure. Salt lake brine flows into the outer ring of this structure, undergoing salt precipitation during its slow flow. The brine flow rate is controlled at 5 m / day by the inlet gate in the outer ring and the pump speed for collecting old brine in the inner ring. Hydrated salt phase change energy storage materials are incorporated into the dam construction; these are sodium sulfate-sodium chloride-ammonium chloride eutectic systems, with sulfuric acid comprising 50% by mass, sodium chloride 15% by mass, and the remainder being ammonium chloride. Insulation material, specifically plastic foam board, is laid at the bottom of the salt field. A connected heating pipe is installed above the insulation material. The heating pipe is made of high-temperature resistant and aging-resistant plastic, carries hot water internally, and has an anti-salt-forming surface. The raw material processed by this salt field is sodium sulfate subtype salt lake brine, the main component of which is Li. + Na+ K + Cl – and SO4 2– The process involves segmented control, first evaporating the brine at a controlled temperature of 15°C until the sodium sulfate and sodium chloride are saturated with Li. + The brine nearing saturation was frozen at -15°C, then the frozen brine was poured out and evaporated at a controlled temperature of 15°C. The evaporation phase diagram is shown below. Figure 8 As shown, the products at each stage of brine evaporation are as follows: Figure 9 As shown.

[0078] Based on production needs, specially designed forklifts are used. These forklifts have wheels that can travel on the embankment, and their buckets can reach the bottom of the pool to remove salt products, dry them, and then send them to the workshop for further processing. The old brine in the inner ring of the spiral-progressive salt pan, which does not require further refining in the salt pan, is transported downstream to the workshop for processing via pipelines and pumps. To prevent premature crystallization and loss of lithium as double salts during evaporation, and to ensure its continuous enrichment in the liquid phase, thereby increasing lithium concentration and yield, the brine is frozen in winter to remove sulfate ions.

[0079] In winter, the temperature of brine in the salt lake area fluctuates around -15℃. Therefore, theoretically, -15℃ is the optimal freezing temperature for the brine, and this discussion will focus on this topic. During the brine evaporation season, the air temperature is around 15℃, making temperature control at 15℃ the easiest to achieve.

[0080] To prevent the brine from freezing in winter, it was concentrated at 15℃ to Li + Freezing is then performed again when the solution approaches saturation. The resulting lithium-rich brine contains Li... + The content is 7.02%, and the yield is as high as 87.29%.

[0081] Example 4

[0082] The salt field used in this embodiment has a spiral-progressive structure. Salt lake brine flows into the outer ring of this structure, undergoing salt precipitation during its slow flow. The brine flow rate is controlled at 25 m / day by the inlet gate in the outer ring and the pump speed for collecting old brine in the inner ring. Hydrated salt phase change energy storage materials are incorporated into the dam construction; these are sodium sulfate-sodium chloride-ammonium chloride eutectic systems, with 80% sulfuric acid, 5% sodium chloride, and the remainder being ammonium chloride. Insulation material, specifically rock wool board, is laid at the bottom of the salt field. A connected heating pipe is installed above the insulation material. The heating pipe is made of high-temperature resistant and aging-resistant plastic, carries hot water internally, and has an anti-salt-forming surface. The raw material processed by this salt field is sodium sulfate subtype salt lake brine, the main component of which is Li. + Na + K + Cl – and SO4 2–Segmented control is implemented, with temperature maintained at 50℃ throughout the entire process. The evaporation phase diagram is as follows. Figure 10 As shown, the products at each stage of brine evaporation are as follows: Figure 11 As shown.

[0083] Based on production needs, specially designed forklifts are used. These forklifts have wheels that can travel on the embankment, and their buckets can reach the bottom of the pools to remove salt products, dry them, and then send them to the workshop for further processing. The old brine, which does not require further refining in the inner ring of the spiral-progressive salt pan, is transported downstream to the processing workshop via pipelines and pumps. The brine evaporation process is controlled at 0℃ throughout, resulting in lithium-rich brine containing Li... + The content reached 7.42%, while Li + The yield was significantly better than that of room temperature evaporation (16.64%), reaching 81.9%.

[0084] Example 5

[0085] The salt field used in this embodiment has a spiral progressive structure. Salt lake brine flows into the outer ring of this structure, undergoing salt precipitation during its slow flow. The brine flow rate is controlled at 50 m / day by the inlet gate in the outer ring and the pump speed for collecting old brine in the inner ring. Hydrated salt phase change energy storage material is incorporated into the dam construction; this is a magnesium chloride-sodium nitrate-sodium nitrite-water eutectic system with the following composition: 20% magnesium chloride, 40% sodium nitrate, 0.5% water, and the remainder sodium nitrite. Insulation material, specifically rock wool board, is laid at the bottom of the salt field. A connected heating pipe is installed above the insulation material. The heating pipe is made of high-temperature resistant and aging-resistant plastic, carries steam internally, and has an anti-salt-forming surface. The raw material processed by this salt field is sodium sulfate subtype salt lake brine, the main component of which is Li. + Na + K + Cl – and SO4 2– Segmented control is implemented, with temperature maintained at 50℃ throughout the entire process. The evaporation phase diagram is as follows. Figure 12 As shown, the products at each stage of brine evaporation are as follows: Figure 13 As shown.

[0086] Based on production needs, specially designed forklifts are used. These forklifts have wheels that can travel on the embankment, and their buckets can reach the bottom of the pools to remove salt products, dry them, and then send them to the workshop for further processing. The old brine, which does not require further refining in the inner ring of the spiral-progressive salt pan, is transported downstream to the processing workshop via pipelines and pumps. The temperature is controlled at 50℃ throughout the entire process. The lithium-rich brine obtained during the brine evaporation and crystallization process contains Li... + The content was higher than 0℃ throughout the entire temperature control process, reaching 7.56%, Li +The yield was 45.72%, which is much higher than that of room temperature evaporation (16.64%), and the evaporation rate was fast, which greatly shortened the production cycle.

[0087] Example 6

[0088] The salt field used in this embodiment has a spiral progressive structure. Salt lake brine flows into the outer ring of this structure, undergoing salt precipitation during its slow flow. The brine flow rate is controlled at 100 m / day by the inlet gate in the outer ring and the pump speed for collecting old brine in the inner ring. Hydrated salt phase change energy storage material is incorporated into the dam construction; this is a magnesium chloride-sodium nitrate-sodium nitrite-water eutectic system with the following composition: 60% magnesium chloride, 35% sodium nitrate, 3% water, and the remainder sodium nitrite. Insulation material, specifically aluminum magnesium silicate, is laid at the bottom of the salt field. A connected heating pipe, made of high-temperature resistant and aging-resistant plastic, is installed above the insulation material. The pipe carries steam and has an anti-salt-forming surface. The raw material processed by this salt field is sodium sulfate subtype salt lake brine, the main component of which is Li. + Na + K + Cl – and SO4 2– The process involves segmented control, first evaporating the brine at a controlled temperature of 15°C until the sodium sulfate and sodium chloride are saturated with Li. + The brine nearing saturation was frozen at -15°C, then the frozen brine was poured out and evaporated at a controlled temperature of 15°C. The evaporation phase diagram is shown below. Figure 14 As shown, the products at each stage of brine evaporation are as follows: Figure 15 As shown.

[0089] Based on production needs, specially designed forklifts are used. These forklifts have wheels that can travel on the embankment, and their buckets can reach the bottom of the pools to remove salt products, dry them, and then send them to the workshop for further processing. The old brine, which does not require further processing in the inner ring of the spiral-progressive salt pan, is transported downstream to the workshop for treatment via pipelines and pumps. The winter brine temperature in the salt lake area fluctuates around -15℃, so theoretically, a brine freezing temperature of -15℃ can be selected for discussion. During the brine evaporation season, the air temperature is around 15℃, making temperature control at 15℃ the easiest to achieve.

[0090] To prevent the brine from freezing in winter, it was concentrated at 15℃ to Li + Freezing is then performed again when the solution approaches saturation. The resulting lithium-rich brine contains Li... + The content is 7.13%, and the yield is as high as 88.49%.

[0091] Based on the above embodiments, it is clear that the embodiments of the present invention, through the spatial structure design of salt fields, use a spiral structure from the outside to the inside to distinguish two different salt-producing areas, concentrating important salt precipitation nodes in a very small central area. This facilitates low-cost artificial control of brine temperature and convection conditions in this area, making it possible to controllably form salt on a large scale based on phase chemical salt formation theory. At the same time, the brine forms salt during its flow, preventing different salt components from having different spatial distributions in the brine channel according to the salt precipitation sequence, making it easier to accurately obtain salt products.

[0092] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A spiral-progressive controllable salt-forming structure for salt fields, characterized in that, It includes a brine flow channel arranged in a spiral pattern and a temperature control device. The outer periphery of the spiral pattern is a first salt-producing zone for the precipitation of a first salt, and the central region of the spiral pattern is a second salt-producing zone for the precipitation of a second salt. The economic value of the first salt is lower than that of the second salt. The temperature control device is located in the central area and is used to precisely regulate the temperature of the brine in the central area.

2. The spiral progressive salt-forming structure of a salt field according to claim 1, characterized in that, As the brine evaporates and concentrates: When the first salt precipitates out of the brine before the second salt, the outermost ring of the spiral pattern is provided with a brine inlet, which is connected to the brine flow channel; a brine pump is provided at the center of the spiral pattern to extract the remaining brine after concentration and salt precipitation. Alternatively, when the first salt precipitates out of the brine later than the second salt, a brine pump is provided on the outermost ring of the spiral pattern; a brine inlet is provided at the center of the spiral pattern.

3. The spiral progressive salt-forming structure of a salt field according to claim 1, characterized in that, The brine channel is formed by two dams on both sides, and the dams contain phase change energy storage materials.

4. The spiral progressive salt field controllable salt-forming structure according to claim 3, characterized in that, The phase change energy storage material includes a single inorganic salt system or a hydrated salt eutectic system; The single inorganic salt system includes a phase change inorganic salt and an additive. The phase change inorganic salt includes sodium sulfate decahydrate or calcium chloride hexahydrate. The additive includes any one or a combination of two or more of xanthan gum, expanded graphite, and sodium hexametaphosphate. The hydrated salt eutectic system includes any one of the following: sodium sulfate-sodium chloride-ammonium chloride eutectic system and magnesium chloride-sodium nitrate-sodium nitrite-water eutectic system.

5. The spiral progressive salt field controllable salt-forming structure according to claim 3, characterized in that, It also includes an extraction device, which comprises a walking module and a digging module. The walking module travels in the opposite direction of the brine channel using the dam. The digging module is fixedly connected to the walking module and has a digging mechanical arm that can extend into the brine channel to transfer the salt precipitated in the brine channel to the outside of the brine channel.

6. The spiral progressive salt field controllable salt-forming structure according to claim 1, characterized in that, The temperature control device includes insulation material laid at the bottom of the central area and heating pipes disposed above the insulation material, wherein a heat medium can be passed through the heating pipes.

7. A method for controlled salt formation in salt fields, characterized in that, include: The brine is allowed to flow into the spiral progressive salt field controllable salt formation structure as described in any one of claims 1-6 and flow along the direction of the brine flow channel. During the flow, the water in the brine evaporates, the first salt is precipitated in the outer peripheral area of ​​the spiral pattern, and the second salt is precipitated in the central area of ​​the spiral pattern. In this case, the temperature of the brine in the central region is controlled by artificial intervention.

8. The method for controlled salt formation in salt fields according to claim 7, characterized in that, Specifically, it includes: Based on the composition information of the brine, the evaporation route is calculated and planned using the solubility phase diagram; Based on the evaporation route, a staged salt precipitation path is obtained; Based on the described phased salt precipitation path, the target temperature of the central region is adjusted.

9. The method for controlled salt formation in salt fields according to claim 7, characterized in that, The brine is sourced from salt lake brine.

10. The method for controlled salt formation in salt fields according to claim 7, characterized in that, In the brine channel, the flow rate of the brine is 0.5 m-100 m / day.

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