A resource utilization system for acid-alkali co-production from salt lake tailings

Abstract

This invention provides a resource utilization system for the combined acid and alkali production of salt lake tailings. In the material conveying direction, the system includes a tailings dissolving device, a purification device, a chelating resin device, a first pH adjusting device, a boron removal resin device, and a bipolar membrane device connected in sequence. The feed end of the tailings dissolving device is connected to a tailings input pipeline and an acid input pipeline. The purification device is suitable for removing mud and sand impurities and reducing the concentration of sulfate and magnesium ions. The discharge end of the bipolar membrane device is connected to a hydrochloric acid collection tank and a sodium hydroxide collection tank, respectively. This resource utilization system for the combined acid and alkali production of salt lake tailings has a simple structure, not only realizing the comprehensive utilization of salt lake resources but also reducing the cost of acids and alkalis in lithium extraction from salt lakes.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, and in particular to a resource utilization system for the co-production of acid and alkali from salt lake tailings. Background Technology

[0002] With the deepening development of salt lake resources in my country, the problem of large amounts of tailings generated during the production of potassium magnesium fertilizer has become increasingly prominent. Traditional processes, using potassium chloride and potassium magnesium sulfate as core products, extract target elements through processes such as evaporation, crystallization, and flotation. However, the residual brine still contains large amounts of unused impurities such as sodium chloride, magnesium sulfate, and sodium borate. Statistics show that producing 1 ton of potassium magnesium fertilizer generates 3-5 cubic meters of tailings. 3 High-salinity tailings brine typically has a TDS concentration exceeding 300 g / L. Long-term storage poses environmental risks such as soil salinization and groundwater pollution. While existing membrane separation processes can achieve partial element enrichment, they suffer from a surge in operating costs due to membrane fouling (more than 25% higher than traditional processes). CN222099565U discloses a resource recovery system for carbonate brine. This system includes a nanofiltration unit, an adsorption and desorption unit, and a concentration and separation unit connected in sequence, as well as reverse osmosis and electrodialysis concentration components. This system primarily employs a membrane separation process, resulting in high operating costs.

[0003] More notably, sodium chloride accounts for over 95% of the sodium precipitate from the desodium-treated salt fields, with smaller amounts of magnesium chloride and magnesium sulfate. Current technologies primarily treat these as waste, failing to achieve resource utilization of sodium salts and resulting in the ineffective loss of over one million tons of industrial salt annually. Simultaneously, the large pH fluctuation range of the tailings brine (4.5-8.5) leads to frequent scaling on pipe walls (annual scale thickness > 5 mm) and material corrosion in existing crystallization equipment, severely impacting equipment lifespan. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a resource utilization system for the co-production of acid and alkali from salt lake tailings. This system is used to prepare acid and alkali from sodium chloride in the tailings, so as to solve the problem of low resource utilization of potassium magnesium fertilizer tailings from salt lakes in the prior art.

[0005] To achieve the above and other related objectives, this utility model provides a resource utilization system for the co-production of acid and alkali from salt lake tailings. In the material conveying direction, the system includes a tailings dissolving device, a purification device, a chelating resin device, a first pH adjusting device, a boron removal resin device, and a bipolar membrane device connected in sequence. The feed end of the tailings dissolving device is connected to the tailings input pipeline and the acid input pipeline. The purification device is suitable for removing mud and sand impurities and reducing the concentration of sulfate ions and magnesium ions. The discharge end of the bipolar membrane device is connected to a hydrochloric acid collection tank and a sodium hydroxide collection tank, respectively.

[0006] In this invention, the hydrochloric acid collection tank is connected to the acid input pipeline.

[0007] In this invention, the impurity removal device includes a filter press, an ultrafiltration, and a nanofiltration mechanism connected sequentially along the material conveying direction. The feed end of the filter press is connected to the discharge end of the tailings dissolving device, and the discharge end of the nanofiltration mechanism is connected to the feed end of the chelating resin device.

[0008] Preferably, the nanofiltration mechanism employs a tubular nanofiltration membrane.

[0009] Preferably, the first filter press filtration mechanism is a plate and frame filter press.

[0010] In this invention, the impurity removal device includes a second pH adjustment mechanism, a filter press filtration mechanism, a third pH adjustment mechanism, and an ultrafiltration mechanism connected sequentially along the material conveying direction. The feed end of the second pH adjustment mechanism is connected to the discharge end of the tailings dissolving device, and the discharge end of the ultrafiltration mechanism is connected to the feed end of the chelating resin device.

[0011] Preferably, the second filter press filtration mechanism is a plate and frame filter press.

[0012] Preferably, the second pH adjustment mechanism is connected to the NaOH solution inlet pipe, and the third pH adjustment mechanism is connected to the acid inlet pipe. More preferably, the NaOH solution inlet pipe is connected to the sodium hydroxide collection tank, and the acid inlet pipe is connected to the hydrochloric acid collection tank.

[0013] In this invention, the first pH adjusting device is connected to the NaOH solution inlet pipe. Preferably, the NaOH solution inlet pipe is connected to the sodium hydroxide collection tank.

[0014] In this invention, the boron removal resin device is equipped with boron removal resin filler.

[0015] As described above, the resource utilization system for acid-alkali co-production from salt lake tailings of this utility model has the following beneficial effects:

[0016] This utility model's resource utilization system for the combined acid-alkali production of salt lake tailings first dissolves the tailings using a tailings dissolving device, then removes impurities such as mud and sand, as well as some sulfate and magnesium ions, using a purification device. Next, it further reduces the magnesium ion concentration using a chelating resin device, then adjusts the pH to further remove boron in a boron removal resin device. Finally, the product water is used for bipolar membrane treatment to obtain hydrochloric acid and sodium hydroxide. These products can be recycled within the salt lake tailings combined acid-alkali production system of this utility model, or further used in the production of lithium from salt lakes. This utility model's resource utilization system for the combined acid-alkali production of salt lake tailings has a simple structure, not only achieving comprehensive utilization of salt lake resources but also having low manufacturing costs, while simultaneously reducing the cost of acids and alkalis in the salt lake lithium extraction process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram (I) of the resource utilization system for the combined acid and alkali production of salt lake tailings according to this utility model.

[0018] Figure 2 This is a schematic diagram (II) of the resource utilization system for the combined acid and alkali production of salt lake tailings according to this utility model.

[0019] Explanation of icon numbers

[0020] 1. Tailings dissolution unit

[0021] 2. Impurity removal device

[0022] 3. Chelating Resin Device

[0023] 4 First pH Adjustment Device

[0024] 5. Boron Resin Removal Device

[0025] 6. Bipolar Membrane Device

[0026] 7. Hydrochloric acid collection tank

[0027] 8 Sodium hydroxide collection tank

[0028] 20 Second pH Adjustment Mechanism

[0029] 21 First Filter Press Filtration Mechanism

[0030] 22 First Ultrafiltration Unit

[0031] 23 Nanofiltration Mechanism

[0032] 24 Second Filter Press Filtration Mechanism

[0033] 25 Third pH adjustment mechanism

[0034] 26 Second Ultrafiltration Unit Detailed Implementation

[0035] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0036] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0037] In this invention, 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. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0038] Please refer to the accompanying drawings. It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show the components related to this utility model and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0039] This utility model embodiment provides a resource utilization system for the combined acid and alkali production of salt lake tailings. In the material conveying direction, the system includes a tailings dissolving device 1, a purification device 2, a chelating resin device 3, a first pH adjusting device 4, a boron removal resin device 5, and a bipolar membrane device 6 connected in sequence. The feed end of the tailings dissolving device 1 is connected to the tailings input pipeline and the acid input pipeline. The purification device 2 is suitable for removing mud and sand impurities and reducing the concentration of sulfate ions and magnesium ions. The discharge end of the bipolar membrane device 6 is connected to the hydrochloric acid collection tank 7 and the sodium hydroxide collection tank 8, respectively.

[0040] In this invention, a tailings dissolving device is used to dissolve the tailings into a salt solution with a salt concentration of 5% to 20%. Then, a purification device 2 removes impurities such as mud and sand, as well as large amounts of sulfate and magnesium ions. A chelating resin device 3 further reduces the magnesium ion concentration in the tailings solution to below 1 ppm. The pH of the solution is then adjusted to 9-11 by a first pH adjustment device 4, and a boron removal resin device 5 reduces the boron concentration to below 5 ppm. The permeate from the preceding process is treated by a bipolar membrane device 6 to obtain hydrochloric acid and sodium hydroxide. This invention's resource utilization system for acid-alkali co-production from salt lake tailings allows for the selection of different purification devices 2 for further processing based on the magnesium ion content in the solution after dissolution in the tailings dissolving device 1.

[0041] In a preferred embodiment, such as Figure 1 As shown in the embodiment of this utility model, in the resource utilization system for acid-alkali co-production of salt lake tailings, the impurity removal device 2 includes a first filter press filtration mechanism 21, a first ultrafiltration mechanism 22, and a nanofiltration mechanism 23 connected sequentially along the material conveying direction. The feed end of the first filter press filtration mechanism 21 is connected to the discharge end of the tailings dissolving device 1, and the discharge end of the nanofiltration mechanism 23 is connected to the feed end of the chelating resin device 3.

[0042] The first filter press filtration mechanism 21 is a plate and frame filter press. The first filter press filtration mechanism 21 is suitable for filtering the salt solution formed by dissolving tailings to remove impurities such as mud and sand.

[0043] The first ultrafiltration unit 22 is adapted to further remove impurity particles from the solution.

[0044] The nanofiltration unit 23 employs a tubular nanofiltration membrane. This nanofiltration unit 23 can remove more than 95% of sulfate ions and magnesium ions from the salt solution.

[0045] In a preferred embodiment, such as Figure 2 As shown in the embodiment of this utility model, in the resource utilization system for acid-alkali co-production of salt lake tailings, the impurity removal device 2 includes a second pH adjustment mechanism 20, a second filter press filtration mechanism 21, a third pH adjustment mechanism 24, and a second ultrafiltration mechanism 22 connected sequentially along the material conveying direction. The feed end of the second pH adjustment mechanism 20 is connected to the discharge end of the tailings dissolving device 1, and the discharge end of the second ultrafiltration mechanism 22 is connected to the feed end of the chelating resin device 3.

[0046] The second pH adjustment mechanism 20 is connected to the NaOH solution inlet pipeline, and the third pH adjustment mechanism 25 is connected to the acid inlet pipeline. The NaOH solution inlet pipeline is connected to the sodium hydroxide collection tank 8, and the acid inlet pipeline is connected to the hydrochloric acid collection tank 7. The second pH adjustment mechanism 20 can adjust the pH value of the salt solution formed by dissolving tailings to 11-13, so that a large amount of magnesium ions precipitate out as magnesium hydroxide. The third pH adjustment mechanism 25 restores the pH of the solution after removing magnesium hydroxide precipitate and silt impurities to 8-9, providing a weakly alkaline environment for subsequent ultrafiltration and chelation.

[0047] The second filter press filtration mechanism 24 is a plate and frame filter press. In this process, the second filter press filtration mechanism 24 is suitable for removing precipitated magnesium hydroxide and silt impurities.

[0048] The second ultrafiltration unit 22 is adapted to further remove impurity particles from the solution.

[0049] In a preferred embodiment, the hydrochloric acid collection tank 7 is connected to the acid inlet pipeline. The hydrochloric acid produced by the resource utilization system for acid-alkali co-production from salt lake tailings of this invention can be reused in this system.

[0050] In a preferred embodiment, the first pH adjustment device 4 is connected to the NaOH solution inlet pipeline. The first pH adjustment device 4 adjusts the pH of the permeate after chelation resin treatment to 9-11, providing conditions for subsequent membrane separation.

[0051] The NaOH solution input pipeline is connected to the sodium hydroxide collection tank 8. The NaOH solution prepared by this resource utilization system for acid-alkali co-production from salt lake tailings can be reused in this system.

[0052] In a preferred embodiment, the boron removal resin device 5 is equipped with boron removal resin filler. The boron removal resin device 5 can reduce the boron concentration in the above solution to below 5 ppm.

[0053] Example 1

[0054] This embodiment provides a resource utilization system for the co-production of acid and alkali from salt lake tailings, such as... Figure 1 As shown:

[0055] In the material conveying direction, the system includes a tailings dissolving device 1, a purification device 2, a chelating resin device 3, a first pH adjusting device 4, a boron removal resin device 5, and a bipolar membrane device 6 connected in sequence.

[0056] The feed end of the tailings dissolving device 1 is connected to the tailings input pipeline and the acid input pipeline, and the tailings are dissolved into a salt solution with a salt concentration of 5% to 20% by the acid solution.

[0057] The impurity removal device 2 includes a first filter press filtration mechanism 21, a first ultrafiltration mechanism 22, and a nanofiltration mechanism 23 connected sequentially along the material conveying direction. The feed end of the first filter press filtration mechanism 21 is connected to the discharge end of the tailings dissolving device 1, and the discharge end of the nanofiltration mechanism 23 is connected to the feed end of the chelating resin device 3. The first filter press filtration mechanism 21 is a plate and frame filter press, and the nanofiltration mechanism 23 is a tubular nanofiltration membrane. The dissolved tailings are filtered through the first filter press filtration mechanism 21 to remove impurities such as mud and sand. Then, the first ultrafiltration mechanism 22 further removes impurity particles from the solution. The nanofiltration mechanism 23 removes 95% of the sulfate and magnesium ions from the salt solution. Finally, the chelating resin device 3 reduces the magnesium in the nanofiltration permeate to below 1 ppm.

[0058] The first pH adjustment device 4 is connected to the NaOH solution input pipeline. The pH of the chelation resin permeate is adjusted to 9-11. After pH adjustment, the boron concentration is reduced to below 5 ppm by the boron removal resin device 5.

[0059] The discharge end of the bipolar membrane device 6 is connected to a hydrochloric acid collection tank 7 and a sodium hydroxide collection tank 8, respectively. The hydrochloric acid collection tank 7 is connected to the acid inlet pipeline, so that the produced acid can be reused for the dissolution of tailings. The sodium hydroxide collection tank 8 is connected to the NaOH solution inlet pipeline, so that the produced alkali can be reused for pH adjustment of the chelating resin permeate. At the same time, the prepared hydrochloric acid and sodium hydroxide solutions can also be used for lithium extraction from salt lakes.

[0060] Example 2

[0061] This embodiment provides a resource utilization system for the co-production of acid and alkali from salt lake tailings, such as... Figure 2 As shown:

[0062] In the material conveying direction, the system includes a tailings dissolving device 1, a purification device 2, a chelating resin device 3, a first pH adjusting device 4, a boron removal resin device 5, and a bipolar membrane device 6 connected in sequence.

[0063] The feed end of the tailings dissolving device 1 is connected to the tailings input pipeline and the acid input pipeline, and the tailings are dissolved in a salt solution with a salt concentration of 5% to 20% by the acid solution.

[0064] The impurity removal device 2 includes a second pH adjustment mechanism 20, a second filter press filtration mechanism 24, a third pH adjustment mechanism 25, and a second ultrafiltration mechanism 26 connected sequentially along the material conveying direction. The feed end of the second pH adjustment mechanism 20 is connected to the discharge end of the tailings dissolving device 1, and the discharge end of the second ultrafiltration mechanism 26 is connected to the feed end of the chelating resin device 3. The second filter press filtration mechanism 24 is a plate and frame filter press. The second pH adjustment mechanism 20 is connected to the NaOH solution input pipeline, and the third pH adjustment mechanism 25 is connected to the acid input pipeline. The pipeline; the pH value of the salt solution is adjusted to 11-13 by the second pH adjustment mechanism 20, causing a large amount of magnesium ions to precipitate as magnesium hydroxide. The precipitated salt solution is then filtered by the second filter press filtration mechanism 24 to remove the precipitated magnesium hydroxide and silt impurities. The pH value is then adjusted back to 8-9 by the third pH adjustment mechanism 25 to provide a weakly alkaline environment for subsequent ultrafiltration and chelation. Next, the second ultrafiltration mechanism 26 further removes impurity particles from the solution. Finally, the chelation resin device 3 reduces the magnesium content in the nanofiltration permeate to below 1 ppm.

[0065] The first pH adjustment device 4 is connected to the NaOH solution input pipeline. The pH of the chelation resin permeate is adjusted to 9-11. After pH adjustment, the boron concentration is reduced to below 5 ppm by the boron removal resin device 5.

[0066] The discharge end of the bipolar membrane device 6 is connected to the hydrochloric acid collection tank 7 and the sodium hydroxide collection tank 8, respectively. The hydrochloric acid collection tank 7 is connected to the acid input pipeline, so that the produced acid can be reused in the tailings dissolving device 1 for tailings dissolution and the third pH adjustment mechanism 25 for pH adjustment. The sodium hydroxide collection tank 8 is connected to the NaOH solution input pipeline, so that the produced alkali can be reused for pH adjustment of the chelating resin permeate. At the same time, the prepared hydrochloric acid and sodium hydroxide solutions can also be used for lithium extraction from salt lakes.

[0067] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A resource utilization system for acid-alkali co-production from salt lake tailings, characterized in that, In the material conveying direction, the system includes a tailings dissolving device (1), a purification device (2), a chelating resin device (3), a first pH adjusting device (4), a boron removal resin device (5), and a bipolar membrane device (6) connected in sequence. The feed end of the tailings dissolving device (1) is connected to the tailings input pipeline and the acid input pipeline. The purification device (2) is suitable for removing mud and sand impurities and reducing the concentration of sulfate ions and magnesium ions. The discharge end of the bipolar membrane device (6) is connected to the hydrochloric acid collection tank (7) and the sodium hydroxide collection tank (8), respectively.

2. The resource utilization system for acid-base co-production from salt lake tailings according to claim 1, characterized in that, The impurity removal device (2) includes a first filter press filtration mechanism (21), a first ultrafiltration mechanism (22) and a nanofiltration mechanism (23) connected in sequence along the material conveying direction. The feed end of the first filter press filtration mechanism (21) is connected to the discharge end of the tailings dissolving device (1), and the discharge end of the nanofiltration mechanism (23) is connected to the feed end of the chelating resin device (3).

3. The resource utilization system for acid-base co-production from salt lake tailings according to claim 1, characterized in that, The impurity removal device (2) includes a second pH adjustment mechanism (20), a second filter press filtration mechanism (24), a third pH adjustment mechanism (25), and a second ultrafiltration mechanism (26) connected sequentially along the material conveying direction. The feed end of the second pH adjustment mechanism (20) is connected to the discharge end of the tailings dissolving device (1), and the discharge end of the second ultrafiltration mechanism (26) is connected to the feed end of the chelating resin device (3).

4. The resource utilization system for acid-base co-production from salt lake tailings according to claim 1, characterized in that, The hydrochloric acid collection tank (7) is connected to the acid input pipeline.

5. The resource utilization system for acid-base co-production from salt lake tailings according to claim 2, characterized in that, The nanofiltration mechanism (23) uses a tubular nanofiltration membrane.

6. The resource utilization system for acid-base co-production from salt lake tailings according to claim 2, characterized in that, The first filter press filtration mechanism (21) is a plate and frame filter press.

7. The resource utilization system for acid-base co-production from salt lake tailings according to claim 3, characterized in that, The second filter press filtration mechanism (24) adopts a plate and frame filter press.

8. The resource utilization system for acid-base co-production from salt lake tailings according to claim 3, characterized in that, The second pH adjustment mechanism (20) is connected to the NaOH solution input pipeline, and the third pH adjustment mechanism (25) is connected to the acid input pipeline.

9. The resource utilization system for acid-alkali co-production from salt lake tailings according to claim 8, characterized in that, The NaOH solution input pipeline is connected to the sodium hydroxide collection tank (8), and the acid input pipeline is connected to the hydrochloric acid collection tank (7).

10. The resource utilization system for acid-base cogeneration from salt lake tailings according to any one of claims 1 to 3, characterized in that, The first pH adjustment device (4) is connected to the NaOH solution input pipeline.

11. The resource utilization system for acid-base co-production from salt lake tailings according to claim 10, characterized in that, The NaOH solution input pipeline is connected to the sodium hydroxide collection tank (8).

12. The resource utilization system for acid-base cogeneration from salt lake tailings according to any one of claims 1-3, characterized in that, The boron removal resin device (5) is equipped with boron removal resin filler.

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