Energy-saving circulating treatment system for lithium extraction tail liquid and waste gas

Abstract

The utility model provides a kind of lithium extraction tail liquid and waste energy-saving cyclic treatment system, the lithium extraction tail liquid and waste energy-saving cyclic treatment system includes extraction unit and with the extraction unit being connected waste gas treatment unit and tail liquid treatment unit;The waste gas treatment unit includes the gas storage component and absorption assembly connected in turn;The absorption assembly includes n level absorption component connected in series, n is 3 at least;The tail liquid treatment unit includes liquid storage component and separation component;The liquid storage component is connected with each absorption component top parallelly;The separation component is connected with each absorption component bottom parallelly;By coupling tail liquid treatment unit with waste gas treatment unit, the synchronous processing of lithium extraction tail liquid and waste is realized, without additional alkali solution, reduce processing cost, while recycling and recycling extraction agent in lithium extraction tail liquid to continue lithium extraction, reduce lithium extraction cost;Realize the energy-saving cycle and green low-cost lithium extraction of lithium precipitation mother liquor, realize waste treatment with waste.

Description

Technical Field

[0001] This utility model belongs to the field of lithium extraction tail liquid and waste gas treatment technology in salt lakes, specifically relating to an energy-saving recycling system for lithium extraction tail liquid and waste gas, and more particularly to an energy-saving recycling system for lithium extraction tail liquid and waste gas after lithium extraction by lithium precipitation mother liquor extraction method. Background Technology

[0002] The mother liquor for lithium precipitation mainly comes from the liquid remaining after lithium sulfate solution reacts with sodium carbonate (or sodium hydroxide) to precipitate lithium carbonate (or lithium hydroxide). Its typical characteristics include: (1) complex composition: containing incompletely precipitated residual lithium salts (Li... + Excessive precipitant (such as Na2CO3 or Na2SO4), byproducts of the reaction, and impurity ions introduced by the raw materials (such as Na+) + K + Mg 2+ Ca 2+ or SO4 2- (2) High salt content: The total dissolved solids (TDS) are high, and improper treatment can easily cause environmental pollution. That is, although the lithium content in the lithium precipitation mother liquor is lower than that in the original liquid, the total amount cannot be ignored, and direct discharge will cause waste of resources. Therefore, efficient recovery of lithium and reduction of impurity content in the solution to achieve recycling or discharge in compliance with standards are the current treatment goals of lithium precipitation mother liquor in this field.

[0003] Commonly used methods for treating lithium extraction mother liquor include lithium phosphate precipitation, recycling, solar pond evaporation, and solvent extraction. Among these, solvent extraction has many advantages, such as high lithium extraction efficiency, simple operation, strong continuity, and low fixed investment. However, as the main process, solvent extraction is less environmentally friendly in practical applications. Some organic matter is easily left in the tail liquor, requiring additional processes for oil removal. The tail gas composition is complex, requiring additional alkaline absorption, resulting in low treatment efficiency and high cost. Moreover, existing treatment devices for lithium extraction tail liquor and exhaust gas from salt lakes have not yet achieved simultaneous treatment of tail liquor and exhaust gas. They are still treated separately, resulting in complex equipment, low treatment efficiency, high cost, and resource waste.

[0004] CN117383730A discloses a treatment system for lithium extraction wastewater from salt lakes using an extraction method. This system includes an air flotation unit, an adsorption unit, a filtration unit, a hydrogen production unit, and a post-treatment unit. The post-treatment unit includes a lithium adsorption device, a membrane concentration device, and an evaporation crystallization device. However, in this system, the salt color in the evaporation crystallization section exceeds the standard, the sodium sulfate byproduct fails to meet the first-grade industrial product standard, and the lithium concentration in the electrolyzed water is typically <0.3 g / L. The low-concentration lithium enrichment and recovery process is energy-intensive and costly, and it does not achieve simultaneous treatment of lithium extraction wastewater and waste gas.

[0005] CN222715200U discloses an apparatus for recovering lithium carbonate from a lithium extraction solution in a salt lake. Although the apparatus mentions that the waste gas treatment equipment is connected to the vent pipe at the top of the extraction phase separation tank, which is equivalent to an independent waste gas treatment unit and makes reasonable use of the tail liquid, it does not achieve the coupled treatment of tail liquid and waste gas, resulting in resource waste and increased treatment costs.

[0006] In view of the above situation, this utility model provides an energy-saving recycling system for lithium extraction tail liquid and waste gas, especially for the synergistic treatment of lithium extraction tail liquid and waste gas after lithium extraction by lithium precipitation mother liquor extraction method. While the extractant in the lithium extraction tail liquid is recovered, the waste gas meets the emission standards, improves the treatment efficiency, reduces the treatment cost, and realizes waste treatment. Utility Model Content

[0007] To address the problems existing in the prior art, the purpose of this utility model is to provide an energy-saving recycling system for lithium extraction tail liquid and waste gas, particularly an energy-saving recycling system for lithium extraction tail liquid and waste gas after lithium extraction by lithium precipitation mother liquor extraction method. This system achieves synergistic treatment of lithium extraction tail liquid and waste gas, enabling both to meet emission standards and reducing environmental pollution. At the same time, the organic matter in the lithium extraction tail liquid, i.e., the residual extractant, is fully reused, reducing the cost of subsequent lithium extraction and realizing green, clean, and efficient lithium extraction from lithium precipitation mother liquor.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] This utility model provides an energy-saving recycling system for lithium extraction tail liquid and waste gas, the energy-saving recycling system for lithium extraction tail liquid and waste gas includes an extraction unit and a waste gas treatment unit and a tail liquid treatment unit connected to the extraction unit.

[0010] The waste gas treatment unit includes a gas storage component and an absorption component connected in sequence; the absorption component includes n-stage absorption components connected in series, where n≥3, for example, 3, 4, 5, 6, 7, 8, 9 or 10, etc.

[0011] The tail liquid treatment unit includes a liquid storage component and a separation component; the liquid storage component is connected in parallel to the top of each of the absorption components; the separation component is connected in parallel to the bottom of each of the absorption components.

[0012] The lithium extraction tail liquid and waste gas energy-saving recycling system of this utility model couples the tail liquid treatment unit with the waste gas treatment unit and uses an n-stage absorption component (n≥3) to fully utilize the alkaline components in the lithium extraction tail liquid to neutralize the acidic components in the lithium extraction waste gas, achieving compliant emissions. At the same time, a separation component is used to reuse the extractant obtained from the oil-water separation of the lithium extraction tail liquid in the extraction unit, reducing subsequent lithium extraction costs and enabling safe discharge, thereby achieving green, efficient and low-cost lithium extraction from the lithium precipitation mother liquor.

[0013] The lithium extraction tail liquid mentioned in this utility model refers to the raffinate after lithium extraction by lithium precipitation mother liquor extraction method, and its pH is in the range of 8 to 13, for example, it can be 8, 9, 10, 11, 12 or 13, etc.

[0014] The waste gas described in this invention mainly includes HCl and the extractant that volatilizes during the extraction process.

[0015] The following are preferred technical solutions of this utility model, but are not intended to limit the technical solutions provided by this utility model. Through the following preferred technical solutions, the purpose and beneficial effects of this utility model can be better achieved.

[0016] Preferably, the extraction unit includes an extraction component.

[0017] Preferably, the top of the extraction component is connected to the gas storage component.

[0018] Preferably, the bottom side of the extraction component is connected to the liquid storage component.

[0019] Preferably, a filter element is provided between the extraction element and the liquid storage element.

[0020] In a further preferred embodiment, a filter component is provided between the extraction component and the liquid storage component to remove residual solid impurities in the lithium extraction tail liquid, so as to avoid clogging of the subsequent spray components, resulting in poor spraying effect, which in turn prevents the exhaust gas from fully contacting the spray liquid and reduces the exhaust gas treatment efficiency.

[0021] Preferably, the absorption assembly includes 3 to 8 stages of absorption components connected in series, such as 3, 4, 5, 6, 7 or 8 stages.

[0022] Preferably, each of the absorption components is provided with a spray element inside.

[0023] The spraying component described in this invention is mainly used to spray the lithium extraction tail liquid of the liquid storage component for waste gas treatment, and can also spray water.

[0024] Preferably, the waste gas treatment unit further includes a first flow control component.

[0025] The present invention further preferably includes a first flow control component in the exhaust gas treatment unit. The first flow control component is used to control the inflow rate of the exhaust gas to avoid the inflow rate being too large and passing through the absorption component too quickly, which would lead to a poor exhaust gas treatment effect, failure to meet emission standards, or the need to consume a larger amount of lithium extraction tail liquid, or even the need to add other alkaline solutions, thus increasing the treatment cost. At the same time, it avoids the flow rate being too small, which would lead to a poor treatment efficiency and an increase in time and energy costs.

[0026] Preferably, the first flow control component is disposed between the gas storage component and the absorption component near one end of the gas storage component.

[0027] The absorption component near the gas storage component is the first absorption component in the absorption assembly that is closest to the gas storage component.

[0028] Preferably, the waste gas treatment unit further includes an adsorption component.

[0029] The present invention further preferably includes an adsorption component in the waste gas treatment unit, which is mainly used to adsorb organic matter in the waste gas, making the external emission more environmentally friendly.

[0030] Preferably, the adsorption component is connected to the absorption component at the end furthest from the gas storage component.

[0031] The absorption component that is furthest from the gas storage component is the absorption component that is furthest from the gas storage component in the absorption assembly, i.e., the last stage absorption component.

[0032] Preferably, the tail liquid treatment unit further includes a second flow control component.

[0033] Preferably, the second flow control component is disposed between the liquid storage component and each of the absorption components.

[0034] The present invention further preferably includes a second flow control component in the tail liquid treatment unit, and more preferably the second flow control component is disposed between the liquid storage component and each of the absorption components, for real-time regulation of the flow rate of lithium extraction tail liquid into the absorption component, so as to avoid the problems of excessive or insufficient flow rate leading to resource waste and low processing efficiency.

[0035] Preferably, the tail liquid treatment unit further includes a recovery component.

[0036] Preferably, the recycling component is connected to the bottom of the separation component.

[0037] Preferably, a washing component is provided between the extraction component and the recovery component.

[0038] Preferably, the tail liquid treatment unit further includes a waste liquid post-treatment component.

[0039] Preferably, the waste liquid post-treatment component is connected to the separation component.

[0040] The specific operation method of the lithium extraction tail liquid and waste gas energy-saving recycling system of this utility model is as follows:

[0041] The lithium mother liquor is extracted by the extraction unit, and the resulting lithium extraction tail liquid is pumped to the storage unit. The waste gas is introduced into the gas storage unit and passes through each absorption unit of the absorption assembly in sequence. At the same time, the lithium extraction tail liquid in the storage unit is sprayed by each spray element in each of the absorption assemblies to come into contact with the waste gas. After neutralization, the acidic components in the waste gas are removed. The waste gas then passes through the adsorption unit to remove the organic components and finally meets the discharge standards. The lithium extraction tail liquid after passing through the absorption assembly enters the separation unit for oil-water separation. The separated oil, which is the extractant, is recovered to the recovery unit, washed by the washing unit, and then reused in the extraction unit for further lithium extraction. The obtained water enters the waste liquid post-treatment unit for further treatment and is discharged after meeting the standards.

[0042] The flow rate of the exhaust gas is controlled by a first flow control component; the flow rate of the lithium extraction tail liquid is controlled by a second flow control component, and the flow rate of the lithium extraction tail liquid in each absorption component is controlled independently.

[0043] The numerical range described in this utility model includes not only the point values ​​listed above, but also any point values ​​within the numerical range that are not listed. Due to space limitations and for the sake of brevity, this utility model will not exhaustively list all the specific point values ​​included in the range.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] This utility model provides an energy-saving recycling system for lithium extraction tail liquid and waste gas. By coupling the tail liquid treatment unit with the waste gas treatment unit, the alkaline lithium extraction tail liquid is used to neutralize the acidic waste gas without the need to add other alkaline solutions. With the adsorption component, the lithium extraction waste gas can be discharged in compliance with standards. At the same time, combined with the separation component, the extractant in the lithium extraction tail liquid can be recycled and reused. This not only allows the lithium extraction tail liquid to be discharged safely, but also reduces the subsequent lithium extraction cost. It achieves clean and efficient lithium extraction from the lithium precipitation mother liquor, realizing waste treatment and reducing treatment costs. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure and connection relationship of the lithium extraction tail liquid and waste gas energy-saving recycling treatment system provided in Embodiment 1 of this utility model;

[0047] Explanation of reference numerals in the attached drawings: 1. Extraction component; 2. Gas storage component; 3. Liquid storage component; 4. First absorption component; 5. Second absorption component; 6. Third absorption component; 7. Separation component; 8. Recovery component; 9. First flow control component; 10. Adsorption component; 11. First spray component; 12. Second spray component; 13. Third spray component; 14. Second A flow control component; 15. Second B flow control component; 16. Second C flow control component; 17. Washing component; 18. Filtration component; 19. Waste liquid post-treatment component. Detailed Implementation

[0048] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of this utility model and should not be considered as specific limitations thereof.

[0049] It should be understood that in the description of this utility model, the terms "parallel," "series," "away from," "near," "inner," "top," "bottom," and "bottom side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for 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. The terms "first," "second," "third," "second A," "second B," and "second C," etc., do not indicate the importance of the components and therefore should not be construed as limitations on this utility model. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this utility model.

[0050] In the following embodiments or comparative examples, the air supply component provides compressed air, the first dosing component adds a solid acidic agent, and the second dosing component adds a solid alkaline agent.

[0051] I. Implementation Examples

[0052] Example 1

[0053] This embodiment provides an energy-saving recycling system for lithium extraction tail liquid and waste gas, such as... Figure 1 As shown, the lithium extraction tail liquid and waste gas energy-saving recycling system includes an extraction unit and a waste gas treatment unit and a tail liquid treatment unit connected to the extraction unit.

[0054] The extraction unit includes an extraction component 1; the waste gas treatment unit includes a gas storage component 2, a first flow control component 9, an absorption component, and an adsorption component 10 connected in sequence; the absorption component includes three stages of absorption components connected in series, namely a first absorption component 4, a second absorption component 5, and a third absorption component 6; each absorption component is equipped with a spray element, namely a first spray element 11, a second spray element 12, and a third spray element 13; the top of the extraction component 1 is connected to the gas storage component 2; the bottom side of the extraction component 1 is connected to the liquid storage component 3; a filter component 18 is provided between the extraction component 1 and the liquid storage component 3; the first flow control component 9 is located between the gas storage component 2 and the first absorption component 4; the adsorption component 10 is connected to the third absorption component 6;

[0055] The tail liquid treatment unit includes a liquid storage component 3, a second flow control component, a separation component 7, a recovery component 8, and a waste liquid post-treatment component 19; the liquid storage component 3 is connected in parallel to the top of each of the absorption components; the liquid storage component 3 and each of the absorption components are provided with a second flow control component, namely, a second A flow control component 14, a second B flow control component 15, and a second C flow control component 16 in sequence; the separation component 7 is connected in parallel to the bottom of each of the absorption components; the recovery component 8 is connected to the bottom of the separation component 7; a washing component 17 is provided between the extraction component 1 and the recovery component 8; the waste liquid post-treatment component 19 is connected to the separation component 7.

[0056] After adopting the lithium extraction tail liquid and waste gas energy-saving recycling system described in this embodiment, the lithium extraction tail liquid and waste gas can be treated simultaneously without the need for additional alkali solution consumption, and the waste gas can be discharged in compliance with standards. Moreover, the residual extractant in the lithium extraction tail liquid can be recycled to the extraction unit, reducing the subsequent lithium extraction cost, achieving clean production, reducing production costs, and realizing waste treatment.

[0057] Example 2

[0058] This embodiment provides an energy-saving recycling system for lithium extraction tail liquid and waste gas, which includes an extraction unit and a waste gas treatment unit and a tail liquid treatment unit connected to the extraction unit.

[0059] The extraction unit includes an extraction component; the waste gas treatment unit includes a gas storage component, a first flow control component, an absorption component, and an adsorption component connected in sequence; the absorption component includes five absorption components connected in series, namely a first absorption component, a second absorption component, a third absorption component, a fourth absorption component, and a fifth absorption component; each absorption component is equipped with a spray element, namely a first spray element, a second spray element, a third spray element, a fourth spray element, and a fifth spray element; the top of the extraction component is connected to the gas storage component; the bottom side of the extraction component is connected to the liquid storage component; a filter component is provided between the extraction component and the liquid storage component; the first flow control component is located between the gas storage component and the first absorption component; the adsorption component is connected to the fifth absorption component;

[0060] The tail liquid treatment unit includes a liquid storage component, a second flow control component, a separation component, a recovery component, and a waste liquid post-treatment component; the liquid storage component is connected in parallel to the top of each of the absorption components; the liquid storage component and each of the absorption components are provided with a second flow control component, namely, a second flow control component A, a second flow control component B, a second flow control component C, a second flow control component D, and a second flow control component E in sequence; the separation component is connected in parallel to the bottom of each of the absorption components; the recovery component is connected to the bottom of the separation component; a washing component is provided between the extraction component and the recovery component; the waste liquid post-treatment component is connected to the separation component.

[0061] The lithium extraction tail liquid and waste gas energy-saving recycling system described in this example has a treatment efficiency comparable to that of Example 1, and also achieves efficient recovery of the extractant in the lithium extraction tail liquid, reducing subsequent lithium extraction costs.

[0062] Example 3

[0063] This embodiment provides an energy-saving recycling system for lithium extraction tail liquid and waste gas. Except for the absence of a first flow control component, the energy-saving recycling system for lithium extraction tail liquid and waste gas is the same as that in Embodiment 1.

[0064] In this embodiment, the lithium extraction tail liquid and waste gas energy-saving recycling system does not have a first flow control component, so it cannot adjust the inflow of waste gas in real time. When the waste gas flow is too large, it passes through the series absorption component quickly, and the contact time between the lithium extraction tail liquid and the waste gas is too short, so it still cannot meet the emission standards. When the waste gas flow is too small, the treatment efficiency is reduced, increasing time and energy costs.

[0065] Example 4

[0066] This embodiment provides an energy-saving recycling system for lithium extraction tail liquid and waste gas. Except for the absence of a second flow control component, the system is identical to that in Embodiment 1.

[0067] In this embodiment, the lithium extraction tail liquid and waste gas energy-saving recycling system does not have a second flow control component, so it is impossible to adjust the inflow rate of the lithium extraction tail liquid in real time. As a result, when the waste gas treated by the first absorption component enters the second absorption component, it is not necessary to use a large amount of tail liquid for neutralization and absorption treatment, which leads to the waste of lithium extraction tail liquid.

[0068] II. Comparative Example

[0069] Comparative Example 1

[0070] This comparative example provides an exhaust gas treatment device, which is the same as that in Example 1 except that it does not include a tail liquid treatment unit.

[0071] The waste gas treatment device described in this comparative example requires additional spraying of other alkaline solutions into the absorption component during operation, making it impossible to simultaneously treat lithium extraction tail liquid and waste gas, resulting in resource waste. Furthermore, the lithium extraction tail liquid cannot meet emission standards, the extractant cannot be recycled, and the treatment cost increases.

[0072] Comparative Example 2

[0073] This comparative example provides a lithium extraction tail liquid and waste gas treatment system. In this system, the liquid storage component is not connected to each of the absorption components, but is directly connected to the separation component. Otherwise, it is the same as in Example 1.

[0074] The lithium extraction tail liquid and waste gas treatment system described in this comparative example requires additional spraying of other alkaline solutions into the absorption component during operation. Although the tail liquid treatment unit and the waste gas treatment unit are still coupled, the lithium extraction tail liquid is not fully utilized, energy-saving recycling cannot be achieved, and resources are wasted.

[0075] In summary, the lithium extraction tail liquid and waste gas energy-saving recycling system provided by this utility model, especially the lithium extraction tail liquid and energy-saving recycling system after lithium extraction by lithium precipitation mother liquor extraction method, achieves simultaneous treatment of lithium extraction tail liquid and waste gas through the synergistic effect between various components. It eliminates the need to add other alkaline solutions, reduces waste gas treatment costs, and improves the utilization rate of lithium extraction tail liquid. At the same time, it recovers the extractant in the lithium extraction tail liquid and reuses it in the extraction unit for further lithium extraction, reducing lithium extraction costs and achieving green and efficient lithium extraction from lithium precipitation mother liquor.

[0076] The applicant declares that the detailed structural features of this utility model are illustrated through the above embodiments, but this utility model is not limited to the above detailed structural features, that is, it does not mean that this utility model must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to this utility model, equivalent substitutions of selected components, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this utility model.

Claims

1. A lithium extraction tail liquid and waste gas energy-saving recycling system, characterized in that, The lithium extraction tail liquid and waste gas energy-saving recycling system includes an extraction unit and a waste gas treatment unit and a tail liquid treatment unit connected to the extraction unit. The waste gas treatment unit includes a gas storage component and an absorption component connected in sequence; the absorption component includes n-stage absorption components connected in series, where n≥3; The tail liquid treatment unit includes a liquid storage component and a separation component; the liquid storage component is connected in parallel to the top of each of the absorption components; the separation component is connected in parallel to the bottom of each of the absorption components.

2. The lithium extraction tail liquid and waste gas energy-saving recycling system according to claim 1, characterized in that, The extraction unit includes an extraction component; The top of the extraction component is connected to the gas storage component; The bottom side of the extraction component is connected to the liquid storage component.

3. The lithium extraction tail liquid and waste gas energy-saving recycling system according to claim 2, characterized in that, A filter element is provided between the extraction element and the liquid storage element.

4. The lithium extraction tail liquid and waste gas energy-saving recycling system according to claim 3, characterized in that, The absorption assembly includes 3 to 8 stages of absorption components connected in series; Each of the aforementioned absorption components is equipped with a spray element inside.

5. The energy-saving recycling system for lithium extraction tail liquid and waste gas according to claim 4, characterized in that, The waste gas treatment unit also includes a first flow control component; The first flow control component is disposed between the gas storage component and the absorption component near one end of the gas storage component.

6. The lithium extraction tail liquid and waste gas energy-saving recycling system according to claim 5, characterized in that, The waste gas treatment unit also includes an adsorption component; The adsorption component is connected to the absorption component at the end furthest from the gas storage component.

7. The lithium extraction tail liquid and waste gas energy-saving recycling system according to claim 6, characterized in that, The tail liquid treatment unit also includes a second flow control component; The second flow control component is disposed between the liquid storage component and each of the absorption components.

8. The energy-saving recycling system for lithium extraction tail liquid and waste gas according to claim 7, characterized in that, The tail liquid treatment unit also includes a recovery component; The recovery component is connected to the bottom of the separation component.

9. The lithium extraction tail liquid and waste gas energy-saving recycling system according to claim 8, characterized in that, A washing component is provided between the extraction component and the recovery component.

10. The lithium extraction tail liquid and waste gas energy-saving recycling system according to claim 9, characterized in that, The tail liquid treatment unit also includes a waste liquid post-treatment component; The waste liquid post-treatment component is connected to the separation component.

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