Circulating chemical cleaning system and method for continuous ion-exchange adsorption equipment

Abstract

The invention discloses a circulating chemical cleaning system and method for continuous ion-exchange adsorption equipment. And conversion from cleaning of the adsorbent to cleaning of the equipment body is realized. A closed circulation loop is constructed, on the basis of pollution diagnosis, a multi-stage standardized cleaning process is adopted, complex inorganic scale, organic matter, biological slime and other composite pollutants in equipment are systematically removed, and the secondary pollution problem of a clean adsorbent is fundamentally avoided. And the liquid distribution system is uniform in distribution, the operation pressure difference of the system is obviously reduced, and the flow stability is improved. The performance of the adsorbent is fully exerted, the lithium yield is remarkably improved, the magnesium-lithium ratio, the sodium-lithium ratio and other key impurity ratios in the product liquid are comprehensively reduced, and the product quality and the process economy are obviously improved. The whole process is operated in a closed cycle standardization mode, equipment does not need to be disassembled, the maintenance period is short, the cleaning end point is controlled through quantitative indexes, chemical waste and the excessive cleaning risk are effectively avoided, and the comprehensive maintenance cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of lithium extraction adsorption equipment cleaning technology, specifically to a circulating chemical cleaning system and method for idle continuous ion exchange adsorption equipment. Background Technology

[0002] Lithium is a key metallic resource supporting the development of strategic industries such as new energy and new materials. Globally, lithium resources are mainly found in salt lake brines and solid ores, with salt lakes accounting for nearly 60% of reserves, making them an important strategic mineral resource for my country. my country's salt lake brines generally exhibit complex system characteristics such as high magnesium-to-lithium ratios, high salinity, and the coexistence of multiple components, posing a severe challenge to the long-term stable operation of lithium extraction processes and equipment.

[0003] Among numerous lithium extraction technologies, continuous ion exchange and adsorption technology has become one of the core processes for lithium extraction from salt lakes due to its advantages such as high efficiency, environmental friendliness, and ease of continuous operation. The economic viability of this technology highly depends on the stable performance of the adsorbent and the smooth operation of the equipment system. However, the complex characteristics of salt lake brine directly lead to severe scaling and contamination risks for lithium extraction equipment, becoming a key bottleneck restricting process efficiency.

[0004] A high magnesium-to-lithium ratio is the root cause of scaling. The concentration of magnesium ions in brine is often tens to thousands of times higher (by mass) than that of lithium ions. During system operation, due to pH fluctuations, temperature changes, or concentration polarization at the membrane / interface, magnesium ions readily combine with carbonate, sulfate, and hydroxide ions to precipitate hard inorganic scale layers such as calcium carbonate, calcium sulfate, and magnesium hydroxide. These scale layers preferentially nucleate, grow, and gradually thicken on the inner surfaces of equipment, pipes, valves, and critical components such as distributors, eventually blocking fluid channels. This leads to a continuous increase in system differential pressure, uneven flow distribution, and severely affects mass transfer efficiency and separation performance.

[0005] The cleanliness of continuous ion-exchange adsorption equipment directly affects the economics of the entire process. On the one hand, contaminants (including inorganic scale and organic residues) adhering to the inner walls of the equipment and the liquid distribution system will rapidly migrate to the surface of the adsorbent after new adsorbent is added, occupying its active sites. This leads to a 20%–40% decrease in the effective adsorption capacity of the adsorbent, slower adsorption kinetics, and poorer selectivity for magnesium-lithium separation. On the other hand, if the liquid distribution system, composed of precision screens, is partially blocked by contaminants, it will cause uneven fluid distribution, forming "dead zones" or localized high-speed flows. This not only reduces separation efficiency but also accelerates adsorbent wear and causes fluctuations in system pressure and flow, leading to inaccurate automated control.

[0006] Given these challenges, ensuring thorough cleaning of the equipment itself is crucial. However, current industrial cleaning technologies, particularly in the specific field of continuous ion-exchange adsorption, suffer from significant research and development biases and technological limitations: (1) Ideological deviation and lack of focus Existing technological research and development largely focuses on the improvement, regeneration, or cleaning of the adsorbent itself. For example, patent CN202310385659.2's core lies in protecting the titanium-based adsorbent itself and reducing its solubility loss through multi-stage, segmented, low-acid desorption processes; patents CN222288122U and CN223404463U are designed for cleaning or regenerating adsorbents or resins. These solutions generally neglect the systematic cleaning of contaminants adhering to the inner surfaces of the equipment (such as the inner walls of the adsorption column, pipes, distributors, and valve bodies) after the adsorbent is emptied. This results in the clean adsorbent being easily recontaminated by residual contaminants after refilling, and the problem cannot be completely eliminated.

[0007] (2) The cleaning method is inefficient. Traditional manual cleaning or static soaking methods lack effective fluid drive and circulation. The cleaning fluid mainly relies on molecular diffusion to contact with contaminants, resulting in low mass transfer efficiency, long cleaning time, and poor effect. For complex liquid distribution screens and internal flow channels, it is difficult to form effective turbulent scouring, which can easily create permanent cleaning dead zones.

[0008] (3) The technical solution is not specific and is costly. Some patented technologies involving cleaning, such as CN110860517B, involve transferring the exhausted resin from the ion exchange column to a dedicated external washing tower for fluidized bed cleaning. This tower has a complex structure, and its cleaning effect depends on the resin's fluidization state within the tower. This method is ineffective for complex piping networks, valve components, and dead zones within the equipment itself. This invention requires additional large equipment such as washing towers and buffer tanks, resulting in high investment costs. Furthermore, the resin transfer and refilling process is time-consuming and carries the risk of resin breakage. Its overall cost is very high, making it largely impractical.

[0009] (4) Lack of standardization and integration in process control Most existing technologies fail to effectively integrate key functional modules such as heating and temperature control, precision filtration, and online monitoring into the cleaning process targeting the equipment itself. This results in significant fluctuations in cleaning process parameters, heavy reliance on manual experience to determine the endpoint, leading to poor consistency in cleaning quality and low process controllability.

[0010] In summary, given the urgent need for high efficiency, stability, and low cost in the lithium extraction industry from salt lakes, developing a highly efficient, standardized, and quantifiable deep chemical cleaning method for the continuous ion-exchange adsorption equipment to fundamentally solve the system performance degradation problem caused by scaling and contamination has become a critical technological bottleneck that the industry urgently needs to overcome. This invention is proposed based on this clear technological gap and practical need. Summary of the Invention

[0011] Based on the unique background and technological bottlenecks of the lithium extraction industry from salt lakes, and the blind spots in existing technologies that emphasize adsorbents while neglecting equipment cleaning, the purpose of this invention is to provide a circulating chemical cleaning method and system for idle continuous ion-exchange adsorption equipment. This method, by constructing a forced circulation closed loop, integrates multi-stage standardized processes such as alkaline washing, oxidation cleaning, and acid washing, achieving a transformation from "cleaning the adsorbent" to "cleaning the equipment." It effectively avoids secondary contamination of the clean adsorbent by residual pollutants on the equipment's inner walls during reloading, systematically solving the problems of scaling and contamination, ensuring unobstructed internal flow channels, uniform liquid distribution, and that the inner surface meets process cleanliness requirements. This provides a reliable guarantee for adsorbent filling and long-term stable system operation, while significantly reducing maintenance costs and safety risks, offering a completely new technological path for the lithium extraction industry from salt lakes.

[0012] This invention protects a circulating chemical cleaning system for a continuous ion exchange adsorption device, comprising a solution tank, a circulating pump, a heater, a precision filter, and an inlet of the main body of the continuous ion exchange device to be cleaned, which are connected in sequence by pipelines. The outlet of the main body of the continuous ion exchange device to be cleaned is connected to the solution tank, forming a circulation loop. The liquid preparation tanks are multiple, and are containers used for storing, preparing and mixing cleaning solutions of various grades and rinsing water; The circulation pump provides the power source for liquid circulation throughout the cleaning circuit, ensuring that the cleaning fluid can be forced to flow in the circuit at the required flow rate and pressure. The heater is used to heat the cleaning solution and maintain it within a specific temperature range required by the process, so as to enhance the chemical reaction rate and cleaning effect. The precision filter is installed in the loop to filter solid particles that are detached from the equipment during the cleaning process, preventing them from redepositing or damaging the circulation pump. It also includes a detection and sampling unit, including online sensors and sampling valves, for real-time monitoring of cleaning process parameters and collection of water samples for offline analysis; It also includes regulating valves installed on pipelines to control the direction of fluid flow, flow rate, loop switching, or discharge of contaminants.

[0013] Furthermore, the line sensors are thermometers, pH meters, conductivity meters, and flow meters; the main body of the continuous ion exchange equipment to be cleaned is the body with the adsorbent emptied, such as an adsorption column or a rotating disc, and is the target object of the cleaning operation.

[0014] This invention also protects a method for cyclic chemical cleaning of a continuous ion exchange adsorption device, based on the above system, specifically including the following steps: Step 1, System Preparation: Isolate the main body of the continuous ion exchange equipment to be cleaned from the production system, completely remove the internal adsorbent, and connect the outlet of the main body of the continuous ion exchange equipment to the solution tank; the solution tank, circulating pump, heater, precision filter, and inlet of the main body of the continuous ion exchange equipment to be cleaned are connected in sequence to form a circulation loop; Step 2, Pollution Source Analysis: Before cleaning, the water is sampled or injected with 60°C hot water for the first circulation, and the effluent is collected for analysis. The turbidity, total organic carbon (TOC), concentrations of specific ions such as calcium, magnesium, and silicon, pH value and conductivity are measured to diagnose the type of pollution source. The pollution source type is inorganic scale, organic matter, biological slime or their complexes, which provides a basis for developing a targeted cleaning plan. Step 3, Multi-stage cyclic chemical cleaning: Based on the pollution source analysis results, execute alkaline cleaning cycle, oxidative cleaning cycle, and / or acidic cleaning cycle in sequence. When the pollutant type is biological slime and organic matter, execute the alkaline cleaning cycle first, followed by the oxidative cleaning cycle; when the pollutant type is inorganic salt scale, execute the acidic cleaning cycle; when the pollutant type is biological slime, organic matter, and inorganic salt scale, execute the alkaline cleaning cycle first, then the oxidative cleaning cycle, and finally the acidic cleaning cycle. The specific cleaning process is as follows: Alkaline cleaning circulation: Pump a solution containing 1.5~2.0wt% sodium polyphosphate dispersant into an empty continuous cross-linking adsorption system, and add a solution containing 2.0~3.5wt% sodium hydroxide to adjust the pH of the cleaning solution to an alkaline range of approximately 10~12; heat the cleaning solution to 55~60℃ and circulate it at a flow rate of 8~12 BV / h for 6~8 hours, with an operating pressure of 0.2~0.4MPa; drain the cleaning solution and thoroughly rinse the system with reverse osmosis (RO) pure water until the pH of the effluent is close to neutral to ensure complete removal of cleaning solution residues. This step is crucial to prevent the formation of precipitates in subsequent acid-base reactions. Among them, the role of alkaline cleaning is mainly to effectively break down the structure of biological slime by utilizing the complexing and dispersing effects of sodium polyphosphate, to promote the hydrolysis and saponification of organic matter such as oils and proteins by creating an alkaline environment, and to ensure that all these chemical processes can be carried out fully and efficiently through heating and circulation. Oxidative cleaning cycle: Pump a 0.1wt% sodium hypochlorite solution into the system, adjust the pH of the cleaning solution to neutral, heat the cleaning solution to 30~40℃, circulate it at a flow rate of 8~12BV / h for 4~6h, drain the cleaning solution, and rinse with RO pure water until the pH of the effluent is close to neutral and the residual chlorine is <0.1mg / L, to ensure that the cleaning solution residue is completely removed; The role of oxidative cleaning is mainly to hydrolyze sodium hypochlorite in water to generate hypochlorous acid (HClO), which has strong oxidizing properties. Hypochlorous acid can effectively oxidize and destroy the cell walls, cell membranes, and internal enzyme systems of microorganisms. At the same time, it can decompose extracellular polymers (EPS) produced by microbial metabolism, which is the main sticky matrix of biofilm. Alkaline cleaning may not be able to completely destroy all microbial cells and their secreted sticky polymers. The oxidative effect of sodium hypochlorite can fill in the gaps and completely decompose these stubborn organic residues into small molecule organic matter or carbon dioxide and water, thereby completely disintegrating the structure of biofilm. Acidic cleaning cycle: Pump a 3.0~6.0wt% hydrochloric acid solution or a 2.0~4.0wt% citric acid solution (containing corrosion inhibitor) into the system and adjust the pH to 3~4; maintain the hydrochloric acid cleaning solution temperature at 40~60℃ and the citric acid cleaning solution temperature at 50~60℃, and circulate at a flow rate of 8~12 BV / h for 6~8 hours; after completion, drain the solution and rinse the system again with RO pure water until the effluent conductivity is <30µS / cm; finally, dismantle the cleaning loop and prepare for adsorbent refilling; The main functions of acid cleaning include: utilizing the chemical dissolution reaction of hydrochloric acid and citric acid to directly react with insoluble inorganic salt scale, such as calcium carbonate, calcium sulfate, and magnesium hydroxide, converting them into soluble salts or complexes, thereby peeling them off from the equipment surface; acids can react with iron oxides to dissolve them; and organic acids such as citric acid also have excellent complexing ability for iron ions, forming soluble iron citrate complexes to prevent them from redepositing. Step 4, Effect Verification: After cleaning, visually inspect the color of the pipeline, the liquid distribution screen, and the inner wall of the equipment; measure the system operating pressure difference and flow stability after refilling the adsorbent; observe for any leakage during material operation, and monitor the magnesium-lithium ratio, sodium-lithium ratio, boron-lithium ratio, and lithium yield process indicators in the product liquid to comprehensively verify the cleaning effect.

[0015] Compared with existing technologies, the present invention has the following beneficial effects: This invention transforms the traditional method of cleaning adsorbents into cleaning the equipment itself, fundamentally solving the long-standing technical blind spot in the industry where clean adsorbents are re-contaminated by residual pollutants on the equipment's inner walls after repackaging. This represents a shift from addressing symptoms to addressing the root cause. Through a standardized multi-stage cleaning process, from contamination diagnosis to cleaning, it systematically removes complex inorganic scale, organic matter, and biological slime from inside the equipment, effectively restoring flow channel unobstructedness and liquid distribution uniformity. Examples show that the system operating pressure differential is significantly reduced and flow stability is improved after cleaning. The restored cleanliness of the equipment creates an optimal working environment for the adsorbent. Data from these examples show that the lithium yield of the adsorption process is significantly improved after cleaning, and key impurity ratios such as the magnesium-lithium ratio and sodium-lithium ratio in the product liquid decrease and remain stable, directly improving product quality and process economics. The standardized closed-loop process eliminates the need to disassemble the equipment or transfer the adsorbent, shortening the maintenance cycle. Controlling the cleaning endpoint using quantitative indicators such as pH and conductivity avoids chemical waste and the risk of over-cleaning, significantly reducing overall maintenance costs in terms of labor, time, and materials. This system is also applicable to fixed-bed and fluidized-bed equipment with similar system compositions.

[0016] In summary, this invention effectively solves the key maintenance problems of lithium extraction adsorption equipment in salt lakes, and has significant industrial application value in ensuring long-term stable operation of the system, improving production efficiency and product quality, and reducing maintenance costs. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of the method of the present invention; Figure 2 These are before-and-after images of the equipment pipeline cleaning process, as shown in the example. Figure 3 This is a system flowchart of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 A continuous ion-exchange adsorption experimental setup used to simulate lithium extraction from salt lakes experienced performance degradation in its piping and liquid distribution system after long-term operation. The method described in this invention is used for cleaning. 1. System Preparation Connect the main body of the continuous ion exchange equipment to be cleaned to the liquid preparation tank. The liquid preparation tank, circulating pump, heater, precision filter, and the inlet of the continuous ion exchange equipment to be cleaned are connected in sequence to form a circulation loop. 2. Pollution source analysis Before cleaning, the water is sampled or injected with 60°C hot water for the first circulation. The water samples are then analyzed to determine the turbidity, total organic carbon (TOC), concentrations of specific ions such as calcium, magnesium, and silicon, pH value, and conductivity, in order to diagnose the type of pollution source. The pollution source is identified as containing biological slime, organic matter, and inorganic salt scale, which provides a basis for developing a cleaning plan.

[0020] 3. Multi-stage circulating chemical cleaning Based on the pollution source analysis results, the cleaning process is as follows: alkaline cleaning, followed by oxidative cleaning, and finally acidic cleaning. First, perform an alkaline cleaning cycle: Pump a solution containing 2.0 wt% sodium polyphosphate dispersant into the pipeline and liquid distribution system of the empty continuous ion exchange adsorption equipment, and add sodium hydroxide solution to adjust the pH of the cleaning solution to an alkaline range of approximately 10-12; heat the cleaning solution to 55°C and circulate it at a flow rate of 10 BV / h for 8 hours at an operating pressure of 0.4 MPa; drain the cleaning solution and thoroughly rinse the system with RO pure water until the pH of the effluent is close to neutral, ensuring that the sodium polyphosphate residue in the cleaning solution is completely removed. This step is crucial to prevent the formation of precipitates in subsequent acid-base reactions. Next, perform an oxidation cleaning cycle: pump a 0.1wt% sodium hypochlorite cleaning solution into the system, adjust the pH of the cleaning solution to neutral, heat the cleaning solution to 40℃, circulate it at a flow rate of 10BV / h for 6 hours, drain the cleaning solution, and rinse with RO pure water until the pH of the effluent is close to neutral and the residual chlorine is <0.1mg / L, to ensure that the cleaning solution residue is completely removed. Finally, perform an acid cleaning cycle: pump a 2.0wt% citric acid solution (containing corrosion inhibitor) into the system and adjust the pH to 3-4; circulate the citric acid cleaning solution at a temperature of 50℃ for 8 hours at a flow rate of 10BV / h; after completion, drain the solution and rinse the system again with RO pure water until the conductivity of the effluent is <30µS / cm.

[0021] 4. Effect Verification After cleaning, a visual inspection revealed a significant improvement in the color of the pipes (see attached document for details). Figure 2 After refilling the adsorbent, it was found that the column pressure of the continuous ion-exchange adsorption equipment system decreased, the flow rate fluctuated less, there was no leakage in the pipeline with material, and after the equipment had been running for a period of time, the various indicators were stable. The magnesium-lithium ratio, sodium-lithium ratio and boron-lithium ratio decreased and remained stable, and the lithium yield increased. As shown in Table 1, the lithium content and quality of the product were guaranteed.

[0022] Table 1 Comparison of key indicators of the product liquid before and after cleaning <![CDATA[Li + ,mg / L]]> <![CDATA[Mg 2+ ,mg / L]]> Na / Li Mg / Li B / Li Lithium yield Qualified production water before cleaning 859 147 0.63 0.17 0.16 81% Qualified production water after cleaning 955 137 0.42 0.14 0.13 92% Example 2 A high operating differential pressure is observed in an industrial-scale continuous rotary table equipment (model 3085), affecting its stability. The cleaning method of this invention is employed: 1. System Preparation The continuous rotary table 3085 to be cleaned is connected to the liquid preparation tank. The liquid preparation tank, circulating pump, heater, precision filter, and inlet of the continuous rotary table 3085 are connected in sequence to form a circulation loop. 2. Pollution source analysis Before cleaning, the water is sampled or injected with 60°C hot water for the first circulation. The water samples are then analyzed to determine the turbidity, total organic carbon (TOC), concentrations of specific ions such as calcium, magnesium, and silicon, pH value, and conductivity, in order to diagnose the type of pollution source. The pollution source is identified as containing biological slime, organic matter, and inorganic salt scale, which provides a basis for developing a cleaning plan.

[0023] 3. Multi-stage circulating chemical cleaning Based on the pollution source analysis results, the cleaning process is as follows: alkaline cleaning, followed by oxidative cleaning, and finally acidic cleaning. First, perform an alkaline cleaning cycle: Pump a solution containing 2.0 wt% sodium polyphosphate dispersant into an empty continuous rotary RO system (3085), and add sodium hydroxide solution to adjust the pH of the cleaning solution to an alkaline range of approximately 10-12; heat the cleaning solution to 55°C and circulate it at a flow rate of 10 BV / h for 8 hours at an operating pressure of 0.4 MPa; drain the cleaning solution and thoroughly rinse the system with RO pure water until the pH of the effluent is close to neutral, ensuring that the sodium polyphosphate residue in the cleaning solution is completely removed. This step is crucial to prevent the formation of precipitates in subsequent acid-base reactions. Next, perform an oxidation cleaning cycle: pump a 0.1wt% sodium hypochlorite cleaning solution into the system, adjust the pH of the cleaning solution to neutral, heat the cleaning solution to 40℃, circulate it at a flow rate of 10BV / h for 6 hours, drain the cleaning solution, and rinse with reverse osmosis (RO) pure water until the pH of the effluent is close to neutral and the residual chlorine is <0.1mg / L, ensuring that the cleaning solution residue is completely removed. Finally, perform an acid cleaning cycle: pump a 2.0wt% citric acid solution (containing corrosion inhibitor) into the system and adjust the pH to 3-4; circulate the citric acid cleaning solution at a temperature of 50℃ for 8 hours at a flow rate of 10BV / h; after completion, drain the solution and rinse the system again with RO pure water until the conductivity of the effluent is <30µS / cm.

[0024] 4. Effect Verification After cleaning, visual inspection showed significant improvement in the continuous discharge rotary table 3085. Upon refilling with the previous adsorbent, a decrease in column pressure was observed. The inlet pressure of the rotary table 3085 dropped from 4.0 bar before cleaning to a stable range of 2.5-3.0 bar. No leaks were observed in the pipeline carrying the material. After a period of operation, all indicators stabilized, as shown in Table 2.

[0025] Table 2 Comparison of inlet pressure before and after cleaning of the 3085 continuous rotary table Turntable inlet pressure Unit (bar) Qualified production water before cleaning 4.0 Qualified production water after cleaning 2.5-3.0 Comparative Example The same equipment was cleaned using a traditional static immersion method. The removed screens were soaked in acidic or alkaline solutions for 24 hours, while the main body of the equipment was only rinsed with low-pressure water. After cleaning and restarting, the initial system pressure differential decreased, but after 48 hours of operation, the pressure differential quickly returned to the pre-cleaning level. The magnesium-lithium ratio of the product liquid did not improve significantly, indicating that contaminants within the internal flow channels and complex structures of the equipment were not effectively removed, leading to a rapid recurrence of the problem.

[0026] As can be seen from the above embodiments and comparative examples, the systematic, multi-stage cyclic chemical cleaning method provided by the present invention can thoroughly remove various complex pollutants inside the adsorption equipment, fundamentally restore the equipment performance, and achieve significant and lasting results. It solves the long-standing technical blind spot and pain point in the industry of only cleaning the adsorbent without cleaning the equipment.

[0027] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A circulating chemical cleaning system for a continuous ion-exchange adsorption device, characterized in that, The system includes a liquid preparation tank, a circulating pump, a heater, a precision filter, and the inlet of the main body of the continuous ion exchange equipment to be cleaned, which are connected in sequence by pipelines. The outlet of the main body of the continuous ion exchange equipment to be cleaned is connected to the liquid preparation tank, forming a circulation loop. The solution preparation tanks are multiple, and are containers used for storing, preparing and mixing rinsing water for various levels of cleaning solutions; The circulation pump provides the power source for liquid circulation throughout the cleaning circuit, ensuring that the cleaning fluid can be forced to flow in the circuit at the required flow rate and pressure. The heater is used to heat the cleaning solution and maintain it within a specific temperature range required by the process, so as to enhance the chemical reaction rate and cleaning effect. The precision filter is installed in the loop to filter solid particles that are detached from the equipment during the cleaning process, preventing them from redepositing or damaging the circulation pump. The system also includes a detection and sampling unit, including online sensors and sampling valves, for real-time monitoring of cleaning process parameters and collection of water samples for offline analysis; The system also includes regulating valves installed on the pipeline for controlling the direction, flow rate, and loop switching of the fluid.

2. The continuous ion-exchange adsorption equipment circulating chemical cleaning system according to claim 1, characterized in that, The line sensors are thermometers, pH meters, conductivity meters, and flow meters; the main body of the continuous ion exchange equipment to be cleaned is the main body with the adsorbent emptied, and is the target object of the cleaning operation.

3. A method for cyclic chemical cleaning of a continuous ion-exchange adsorption device, characterized in that, The method is implemented based on the system described in claim 2, and specifically includes the following steps: Step 1, System Preparation: Isolate the main body of the continuous ion exchange equipment to be cleaned from the production system, completely remove the internal adsorbent, and connect the outlet of the main body of the continuous ion exchange equipment to the solution tank. The solution tank, circulating pump, heater, precision filter, and inlet of the main body of the continuous ion exchange equipment to be cleaned are connected in sequence to form a circulation loop. Step 2, Pollution Source Analysis: Before cleaning, the water is sampled or injected with 60°C hot water for the first circulation and analyzed to diagnose the type of pollution source and provide a basis for developing a targeted cleaning plan. Step 3, Multi-stage cyclic chemical cleaning: Based on the results of pollution source analysis, perform alkaline cleaning cycle, oxidative cleaning cycle and / or acidic cleaning cycle in sequence; Step 4, Effect Verification: After cleaning, the equipment is tested for appearance, hydraulic performance and process performance to verify the cleaning effect.

4. The method according to claim 3, characterized in that, In step 2, hot water at 60°C is injected for the first circulation; the water sample analysis specifically includes measuring turbidity, total organic carbon, calcium ion concentration, magnesium ion concentration, silicon ion concentration, pH value, and conductivity.

5. The method for cyclic chemical cleaning of a continuous ion-exchange adsorption device according to claim 3, characterized in that, In step 2, the diagnosed contaminant type is biological slime, organic matter, and / or inorganic salt scale; when the contaminant type is biological slime and organic matter, an alkaline cleaning cycle is performed first, followed by an oxidative cleaning cycle; when the contaminant type is inorganic salt scale, an acidic cleaning cycle is performed; when the contaminant type is biological slime, organic matter, and inorganic salt scale, an alkaline cleaning cycle is performed first, followed by an oxidative cleaning cycle, and finally an acidic cleaning cycle.

6. The method according to claim 3, characterized in that, In step 3, the specific parameters of the alkaline cleaning cycle are as follows: the cleaning solution contains 1.5~2.0wt% sodium polyphosphate, 2.0~3.5wt% sodium hydroxide to adjust the pH of the cleaning solution to 10~12, the heating temperature of the cleaning solution is 55~60℃, the circulation flow rate of the cleaning solution is 8~12 BV / h, the circulation time is 6~8h, and the operating pressure is 0.2~0.4MPa.

7. The method according to claim 3, characterized in that, In step 3, the specific parameters of the oxidation cleaning cycle are as follows: the cleaning solution is a 0.1wt% sodium hypochlorite solution, the pH is adjusted to neutral, the residual chlorine is <0.1mg / L, the heating temperature of the cleaning solution is 30~40℃, the circulation flow rate of the cleaning solution is 8~12BV / h, and the circulation time is 4~6h.

8. The method according to claim 3, characterized in that, In step 3, the acidic cleaning cycle uses hydrochloric acid or citric acid solution as the cleaning fluid, and the pH is adjusted to 3-4. The specific parameters are as follows: when using hydrochloric acid, the concentration is 3.0-6.0 wt% and the temperature is 40-60℃; when using citric acid, the concentration is 2.0-4.0 wt% and the temperature is 50-60℃. The circulation flow rate is 8-12 BV / h and the circulation time is 6-8h. Corrosion inhibitors are added to the cleaning fluid.

9. The method according to claim 3, characterized in that, In steps 1 and 3, after each cleaning cycle, the system must be rinsed with RO pure water until the effluent indicators meet the standards. After alkaline and oxidative cleaning, the pH of the effluent should be close to neutral, and after acidic cleaning, the conductivity of the effluent should be <30µS / cm.

10. The method for cyclic chemical cleaning of a continuous ion-exchange adsorption device according to claim 3, characterized in that, In step 4, visually inspect the color of the pipeline, the liquid distribution screen, and the inner wall of the equipment; measure the system operating pressure difference and flow stability after refilling the adsorbent; and monitor the changes and stability of the magnesium-lithium ratio, sodium-lithium ratio, boron-lithium ratio, and lithium yield in the product liquid during operation with material.

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