Experimental apparatus and method for interfacial soil study with real-time monitoring

Abstract

The application discloses an experimental device and method for interface contamination research, and relates to the technical field of chemical liquid-liquid extraction.The method is based on an experimental device with real-time monitoring function for interface contamination research.The device comprises an extraction column, a lower expansion section, a back extraction column and an organic phase washing column.The extraction column is used for separating and extracting metal ions in the feed liquid to realize the extraction process.The lower expansion section is used for real-time observation and sampling analysis of the interface contamination formed in the extraction column.The back extraction column is used for back extracting the metal ions in the organic phase into the aqueous phase feed liquid.The organic phase washing column is used for washing the decomposition products and contamination in the organic phase to realize the purification and reuse of the organic phase.The device and method can realize real-time sampling analysis of the interface contamination structure composition, real-time monitoring of the running stability of the pulse column and the stability of the liquid flow in the column, so that the influence degree of the interface contamination on the running process is determined.

Description

Technical Field

[0001] This invention belongs to the field of chemical liquid-liquid extraction technology, specifically relating to an experimental apparatus and method for studying interface contaminants with real-time monitoring capabilities. Background Technology

[0002] Liquid-liquid extraction is a widely used separation technique in engineering fields such as chemical engineering, pharmaceuticals, and metallurgy. Its basic principle is to utilize the difference in solubility of a substance in two immiscible solvents to transfer the solute from one solvent to the other, thus achieving separation. However, in the liquid-liquid extraction process, especially in the field of nuclear chemical separation, the formation of interfacial contaminants is a common and complex problem.

[0003] Interface contaminants typically form at the interface between two phases, including degradation products of tributyl phosphate (TBP), radiolytic or thermal degradation products of the organic phase, and insoluble substances in the feed solution. These contaminants have a significant impact on the efficiency and quality of liquid-liquid extraction processes. The formation of interface contaminants can lead to reduced performance of extraction equipment, especially pulsed extraction columns, a significant decrease in the purification coefficient, and even deterioration of equipment operation.

[0004] Although the formation of interfacial contaminants and their impact on liquid-liquid extraction processes are widely recognized, current solutions primarily focus on treating existing contaminants, such as using detergents or increasing temperatures. However, these methods are often limited in effectiveness and may introduce additional complexity and cost to the extraction process.

[0005] Therefore, in-depth research into the formation mechanism of interfacial contaminants, and the design and manufacture of liquid-liquid extraction equipment that can effectively prevent their formation, are important research directions in the field of liquid-liquid extraction technology. Methods for studying interfacial contaminants with real-time monitoring and analysis capabilities, as well as methods for studying their formation mechanism, are of great significance for solving the aforementioned problems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an experimental apparatus and method for studying interface contaminants with real-time monitoring capabilities. Using this apparatus and method, the structural composition of interface contaminants can be sampled and analyzed in real time, and the operational stability of the pulse column and the stability of the liquid flow within the column can be monitored in real time, thereby determining the degree of influence of interface contaminants on the operating process.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An experimental method for studying interfacial contaminants is disclosed. This method is based on an experimental apparatus for studying interfacial contaminants with real-time monitoring capabilities. The apparatus includes an extraction column, a lower expansion section, a back-extraction column, and an organic phase washing column. The extraction column is used to separate and extract metal ions from the feed solution, realizing the extraction process. The lower expansion section is used for real-time observation and sampling analysis of interfacial contaminants formed within the extraction column. The back-extraction column is used to back-extract metal ions from the organic phase back into the aqueous feed solution. The organic phase washing column is used to wash away decomposition products and contaminants from the organic phase, realizing the purification and reuse of the organic phase.

[0009] The aqueous phase of the extraction column is the feed liquid to be extracted, and the organic phase is the extractant; the aqueous phase of the back-extraction column is the back-extraction agent, and the organic phase is the organic phase overflow of the extraction column; the aqueous phase of the organic phase washing column is the aqueous phase washing agent, and the organic phase is the organic phase overflow of the back-extraction column; the organic phase overflow of the organic phase washing column is returned to the extractant of the extraction column.

[0010] The lower expansion section is connected to the two-phase interface of the extraction column via a connecting pipe. Interface contaminants in the extraction column are drawn into the lower expansion section by a feed pump, and the interface contaminants accumulate in the lower expansion section.

[0011] A pulse tube is installed at the lower end of the extraction column, back-extraction column and organic phase washing column. The other end of the pulse tube is connected to an air pulse generator to provide pulse vibration.

[0012] The method includes the following steps:

[0013] S1. Prepare the required experimental solution, extractant, back-extraction agent and aqueous washing agent, and adjust the feed flow rate of each solution to the set value;

[0014] S2. The extraction column is filled with extractant, the back-extraction column is filled with back-extraction agent, and the organic phase washing column is filled with aqueous washing agent.

[0015] S3. After the column filling is completed, adjust the pulse amplitude of the extraction column, the back-extraction column and the organic phase washing column, and set the interface value of the extraction column, the back-extraction column and the organic phase washing column to make the extraction column reach stable operating conditions.

[0016] S4. The feed liquid of the extraction column is transported into the extraction column. As the extraction process is running stably, interface contaminants are generated at the interface between the two phases of the extraction column. The growth process of the interface contaminants is observed through the upper clarification section. The interface contaminants in the upper clarification section are sampled for analysis of their composition and structure.

[0017] Furthermore, in the experimental method for studying interfacial contaminants as described above, the extraction column has a two-section structure with a coarser upper section and a thinner lower section. The upper section of the column is provided with an aqueous phase inlet and an organic phase outlet, while the lower section of the column is provided with an organic phase inlet and an aqueous phase outlet near the bottom. The feed liquid to be extracted enters the extraction column through the aqueous phase inlet on the upper section and flows downward, while the extract enters the extraction column through the organic phase inlet on the lower section and flows upward, generating interfacial contaminants at the interface between the two phases. The organic phase overflow liquid of the extraction column is a loaded organic phase and flows out from the organic phase outlet.

[0018] Furthermore, in the experimental method for studying interface contaminants as described above, the top of the lower enlarged section is positioned higher than the top of the extraction column.

[0019] Furthermore, in the experimental method for studying interface contaminants as described above, the upper end of the lower enlarged section has an interface contaminant inlet and an organic phase outlet, and the lower end has a raffinate aqueous phase outlet. The interface contaminant inlet is connected to the interface between the two phases in the extraction column, the organic phase outlet is connected to the organic phase inlet of the extraction column, and the raffinate aqueous phase flows out from the raffinate aqueous phase outlet.

[0020] Furthermore, in the experimental method for studying interface contaminants as described above, the back-extraction column has a three-section structure that is thicker at both ends and thinner in the middle. The upper section has an aqueous phase inlet and an organic phase outlet, and the lower section has an organic phase inlet and an aqueous phase outlet. The back-extraction agent enters the back-extraction column through the aqueous phase inlet and flows downward, exiting from the aqueous phase outlet. The overflow liquid of the loaded organic phase of the extraction column enters the back-extraction column through the organic phase inlet and flows upward, thereby back-extracting the metal ions in the loaded organic phase back into the back-extraction agent. The loaded organic phase after back-extraction becomes an organic-lean phase and flows out from the organic phase outlet.

[0021] Furthermore, in the experimental method for studying interface contaminants as described above, the organic phase washing column has a three-section structure that is thicker at both ends and thinner in the middle. The upper section has an aqueous phase inlet and an organic phase outlet, and the lower section has an organic phase inlet and an aqueous phase outlet. The lean organic phase flowing out of the back-extraction column enters the organic phase washing column through the organic phase inlet and flows upward. The aqueous phase washing liquid enters the organic phase washing column through the aqueous phase inlet and flows downward to wash and purify the lean organic phase. After washing and purification, the lean organic phase flows out from the organic phase outlet and returns to the extract, thereby realizing the recycling of the extract.

[0022] Furthermore, in the experimental method for studying interface contaminants as described above, the organic phase is washed in the organic phase washing column by adding an appropriate amount of detergent and adjusting suitable temperature and pressure conditions.

[0023] Furthermore, in the experimental method for studying interfacial contaminants as described above, the extraction column is equipped with a pulse baffle, and the back-extraction column and the organic phase washing column are equipped with sieve plates to enhance the contact and mixing between the two liquids, thereby improving the extraction efficiency.

[0024] Furthermore, in the experimental method for studying interface contaminants as described above, the extraction column, the lower expansion section, the back-extraction column, and the organic phase washing column are made of high borosilicate glass and have a transparent explosion-proof film reinforcement layer on their surface.

[0025] Furthermore, in the experimental method for studying interfacial contaminants as described above, air blowing pipes and pressure monitoring sensors are installed at different column heights of the extraction column, back-extraction column, and organic phase washing column to monitor the operational stability of the pulse column and the stability of the liquid flow within the column in real time.

[0026] Furthermore, in the experimental method for studying interface contaminants as described above, step S further includes turning on the air compressor and starting the air blowing pressure measurement for online measurement of hydraulic properties.

[0027] Furthermore, in the experimental method for studying interface contaminants as described above, step S involves adjusting the pulse frequency and compressed air source pressure of the extraction column, back-extraction column, and organic phase washing column to achieve a set pulse amplitude.

[0028] Compared with existing technologies, the experimental apparatus and method for studying interface contaminants with real-time monitoring capabilities provided by this invention have the following advantages:

[0029] This invention addresses the problem of interfacial contamination in liquid-liquid extraction equipment by proposing an experimental apparatus consisting of a pulsed baffle extraction column, a pulsed sieve back-extraction column, and a pulsed sieve organic phase washing column. Interfacial contaminants are generated continuously within the extraction column. The formation process of the interfacial contaminants, such as thickness and morphology, can be observed through a lower expansion section, allowing for real-time sampling and analysis of the contaminant structure. Furthermore, the apparatus is equipped with air blowing pipes and pressure monitoring sensors at different column heights to monitor the operational stability of the pulsed column and the stability of the liquid flow within the column in real time, thereby determining the extent to which interfacial contaminants affect the operational process.

[0030] This invention is mainly applicable to spent fuel reprocessing engineering and other engineering fields involving liquid-liquid extraction processes, and is particularly suitable for occasions requiring analysis and treatment of interface contaminants. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of an experimental device with real-time monitoring function for studying interface contaminants, provided in an embodiment of the present invention.

[0032] Figure 2This is a flowchart of an experimental method for studying interface contaminants with real-time monitoring capabilities, provided in an embodiment of the present invention. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0034] Figure 1 This diagram illustrates a schematic of an experimental apparatus for studying interface contaminants with real-time monitoring capabilities, provided in an embodiment of the present invention. The apparatus mainly comprises an extraction column 1, a back-extraction column 2, and an organic phase washing column 3. The primary function of these columns is to provide the necessary interface during the liquid-liquid extraction process, providing space for substance transfer. The extraction column 1 is mainly used to separate and extract metal ions from the aqueous phase, realizing the extraction process; the back-extraction column 2 is mainly used to back-extract metal ions from the organic phase back into the aqueous phase; and the organic phase washing column 3 is used to wash away decomposition products and contaminants from the organic phase, achieving purification and reuse of the organic phase. The structure and function of each part are described in detail below.

[0035] The extraction column 1 has a two-section structure, with a coarser upper section and a thinner lower section. The upper section has an aqueous phase inlet and an organic phase outlet, while the lower section, near the bottom, has an organic phase inlet and an aqueous phase outlet. The feed solution to be extracted enters the extraction column 1 through the aqueous phase inlet on the upper section and flows downwards. The extract in the extract container enters the extraction column 1 through the organic phase inlet on the lower section and flows upwards. The loaded organic phase flows out from the organic phase outlet into the loaded organic phase container. Within the extraction column 1, the two immiscible liquids, the feed solution and the extract, flow up and down within the column, generating interface contaminants at the two-phase interface. A pulse baffle is installed within the extraction column 1 to enhance the contact and mixing between the two liquids, thereby improving the extraction efficiency.

[0036] A lower expansion section 4 (also called an upper clarification section) is provided above the exterior of the extraction column 1, with its top end higher than the top end of the extraction column 1. The upper end of the lower expansion section 4 has an interface contaminant inlet and an organic phase outlet, while the lower end has a raffinate aqueous phase outlet. The interface contaminant inlet is connected to the two-phase interface inside the extraction column 1 via a connecting pipe. Interface contaminants inside the extraction column 1 are drawn into the lower expansion section 4 by a feed pump, where they accumulate. The organic phase outlet of the lower expansion section 4 is connected to the organic phase inlet of the extraction column 1, and the extract flows back into the extraction column 1 from the organic phase outlet of the lower expansion section 4. The raffinate aqueous phase flows out into a raffinate aqueous phase container.

[0037] The extraction column 1 and the lower expansion section 4 are made of high borosilicate glass, with a transparent explosion-proof film reinforcement layer on their surface. The formation process of interface contaminants, including their thickness and morphology, can be directly observed through the transparent lower expansion section 4. A sampling tube is installed on the lower expansion section 4, allowing for the extraction of interface contaminants using external pressure for compositional and structural analysis.

[0038] Extraction column 1 and lower expansion section 4 adopt a separate structure to facilitate the acquisition of interface contaminants for component and structural analysis.

[0039] The back-extraction column 2 has a three-section structure, wider at both ends and narrower in the middle. The upper section has an aqueous phase inlet and an organic phase outlet, while the lower section has both an organic phase inlet and an aqueous phase outlet. The organic phase feed liquid of the back-extraction column 2 is the overflow liquid of the loaded organic phase from the extraction column 1. The back-extractant enters the back-extraction column 2 through the aqueous phase inlet and flows downward, exiting from the aqueous phase outlet into the back-extractant container. The loaded organic phase container is connected to the organic phase inlet of the back-extraction column 2. The overflow liquid of the loaded organic phase from the extraction column 1 enters the back-extraction column 2 through the organic phase inlet and flows upward. The two immiscible liquids, the back-extractant and the loaded organic phase, flow up and down within the back-extraction column 2 to perform back-extraction, thereby back-extracting the metal ions in the loaded organic phase feed liquid back into the back-extractant. The back-extracted loaded organic phase becomes a lean organic phase and flows out from the organic phase outlet into the lean organic phase container.

[0040] A sieve plate is provided inside the back-extraction column 2 to enhance the contact and mixing between the two liquids, thereby improving the back-extraction efficiency.

[0041] In stripping column 2, the stripping process is achieved under low-acid conditions, thereby ensuring the stability of the organic phase.

[0042] The organic phase washing column 3 has a three-section structure, wider at both ends and narrower in the middle. The upper section has an aqueous phase inlet and an organic phase outlet, and the lower section has both an organic phase inlet and an aqueous phase outlet. The organic phase feed liquid of the organic phase washing column 3 is the lean organic phase overflow liquid from the back-extraction column 2. The lean organic phase container is connected to the organic phase inlet of the organic phase washing column 3. The lean organic phase flowing out of the back-extraction column 2 enters the organic phase washing column 3 through the organic phase inlet and flows upward. The aqueous phase washing liquid enters the organic phase washing column 3 through the aqueous phase inlet and flows downward to wash and purify the lean organic phase. The generated aqueous phase waste liquid flows out from the aqueous phase outlet into the aqueous phase waste liquid container. After washing and purification, the lean organic phase becomes a reusable extract liquid, which flows out from the organic phase outlet into the organic phase return container. The organic phase return container is connected to the extract liquid container, thereby realizing the recycling of the extract liquid.

[0043] A sieve plate is installed inside the organic phase washing column 3 to enhance the contact and mixing between the two liquids, thereby improving the washing and purification efficiency.

[0044] In the organic phase washing column 3, the organic phase is washed by adding an appropriate amount of detergent and adjusting the temperature and pressure conditions.

[0045] Pulse tubes are installed at the lower end of the extraction column 1, back-extraction column 2, and organic phase washing column 3. The other end of the pulse tube is connected to an air pulse generator to provide pulse vibration. By adjusting the pulse frequency and compressed air source pressure of the extraction column 1, back-extraction column 2, and organic phase washing column 3, the pulse amplitude reaches the set value.

[0046] The materials of the back-extraction column 2 and the organic phase washing column 3 are also high borosilicate glass, and their surfaces are covered with a transparent explosion-proof film reinforcement layer.

[0047] Air blowing pipes and pressure monitoring sensors are installed at different column heights in extraction column 1, back-extraction column 2, and organic phase washing column 3 to monitor the operational stability of the pulse column and the stability of the liquid flow inside the column in real time.

[0048] Based on the above experimental setup, this embodiment of the invention provides an experimental method for studying interface contaminants with real-time monitoring capabilities. Figure 2 A flowchart of the method is shown, which includes the following steps:

[0049] S1. Prepare the required experimental solution, extractant, back-extraction agent and aqueous washing agent, and adjust the feed flow rate of each solution to the set value;

[0050] S2. The extraction column is filled with extractant, the back-extraction column is filled with back-extraction agent, and the organic phase washing column is filled with aqueous washing agent.

[0051] S3. After the column filling is completed, adjust the pulse amplitude of the extraction column, the back-extraction column and the organic phase washing column, and set the interface value of the extraction column, the back-extraction column and the organic phase washing column to make the extraction column reach stable operating conditions.

[0052] S4. The aqueous feed solution is fed into the extraction column. As the extraction process runs stably, interfacial contaminants are generated at the interface between the two phases of the extraction column. The growth process of the interfacial contaminants is observed through the upper clarification section. Samples of the interfacial contaminants in the upper clarification section are taken to analyze the composition and structure of the interfacial contaminants.

[0053] As the extraction column operates stably under process conditions, interfacial contaminants first form at the interface between the two phases of the extraction column. Their location is determined by the setpoint of the extraction column interface and fluctuates up and down under the influence of pulses. The interfacial contaminants are then pumped into the upper clarification section, where they accumulate. Using the transparent upper clarification section, the thickness change of the interfacial contaminants is measured with a measuring tape, allowing for direct observation of the growth rate of the interfacial contaminants in the clarification section of the extraction column, thereby obtaining the growth morphology and growth curve of the interfacial contaminants. The interfacial contaminants in the upper clarification section are then extracted using external pressure for compositional and structural analysis.

[0054] The research method provided by this invention is a linked operation, which realizes the formation of interfacial contaminants in the extraction unit and monitors and analyzes the degree of influence of interfacial contaminants on the extraction process in real time. The back-extraction process mainly realizes the back-extraction of the extractable components in the organic phase, and the washing column is used to further purify the organic phase so that it can be reused as the extractable phase. This method is because interfacial contaminants require long-term operation to form, but long-term operation requires the use of large amounts of organic phase and radioactive materials, which can easily cause nuclear material loss and burden subsequent recovery process units. By recycling and using organic phase and radioactive liquid, the formation and study of contaminants can be carried out simultaneously, avoiding material loss and waste.

[0055] Example

[0056] By conducting long-term operation experiments of pulse extraction columns for 240-480 hours, this study investigated the formation and accumulation of ash and other contaminants at the interface between the two phases in the 30% TBP / kerosene-HNO3 system, obtained the composition of interface contaminants and understood their formation mechanism, and determined the limit of insoluble matter in the feed solution required for the operation of the extraction column.

[0057] (1) Operating process

[0058] The extraction column section is a baffle plate, the feed solution is 3mol / L nitric acid and nitrate solution, and the feed flow rate is 60-70L / h; the extract is 30% TBP-kerosene, and the feed flow rate is 150-180L / h.

[0059] In the back-extraction column, the loaded organic phase feed liquid is the organic phase overflow liquid of the extraction column (flow rate according to the outlet flow rate), with a feed flow rate of 140-150 L / h; the back-extraction agent is a 0.01-0.05 mol / L nitric acid solution, with a feed flow rate of 160-170 L / h, and a flow ratio of loaded organic phase to back-extraction agent of 1:1.1-1.2.

[0060] In the organic phase washing column, the organic phase feed liquid is the organic phase overflow liquid from the back-extraction column, with a feed flow rate of 140-150 L / h; the aqueous phase washing liquid is a 0.01 mol / L nitric acid solution, with a feed flow rate of 160-170 L / h, and is operated at an organic phase to aqueous phase flow ratio of 1:1.1.

[0061] (2) Equipment operation

[0062] Column packing: The first step in operating a pulse extraction column is column packing. The extraction column uses a continuous organic phase and is packed with 30% TBP-kerosene. Because the clarification tank of the lower clarification section of the extraction column is moved separately to the upper section, no aqueous phase is needed for water sealing in the lower section of the extraction column. The back-extraction and organic phase washing columns use a continuous aqueous phase and are packed with 0.01 mol / L dilute nitric acid. Afterwards, the air compressor is turned on, and the air pressure measurement device is activated for online measurement of hydraulic properties.

[0063] Stable operation: After the column filling is completed, turn on the air pulse generator and adjust the pulse frequency and compressed air source pressure of the extraction column, back-extraction column and organic phase washing column so that the pulse amplitude reaches the size of stable operation of acid test. Set the interface value of the extraction column, back-extraction column and organic phase washing column. The flow rate of the dispersed phase feed of each column is gradually increased from small to large until it reaches the predetermined value. The pulse extraction column enters the stable operation condition.

[0064] Table 1. Setpoints for stable operation parameters of the extraction column acid test

[0065] Column P_tank (gauge pressure) / kPa Pulse frequency / ms Pulse amplitude / cm Adjustment interface Extraction column 145 300 / 700 12 46kPa Back-extraction column 160 300 / 700 15 350mm Organic phase washing column 140 200 / 500 8 400mm

[0066] (3) Growth of interfacial contaminants

[0067] The aqueous feed solution enters the extraction column. As the extraction column operates stably under process conditions, interfacial contaminants first form at the interface between the two phases. Their location is determined by the setpoint of the extraction column interface and fluctuates up and down under pulse action. At this stage, the interfacial contaminants appear as a grayish-black solid-liquid emulsion. They are then pumped into the upper clarification section, where they accumulate. Using the transparent upper clarification section, the thickness change of the interfacial contaminants can be measured with a measuring tape, allowing for direct observation of the growth rate of the interfacial contaminants in the upper clarification section of the extraction column, thus obtaining the growth morphology and growth curve of the interfacial contaminants.

[0068] In this embodiment, the size of the upper clarifying section is The volume is approximately 500L. Observation of the interface contaminants in the upper clarification section revealed that, with the passage of time, the interface contaminants continuously grow and accumulate at the interface between the two phases in the clarification section. Records showed that contaminants began to accumulate in the upper clarification section after about 8 hours of operation; after about 72 hours of operation, the contaminants grew to a thickness of about 1 cm, appearing as black flocculent particles, located between the organic and aqueous phases, and had covered the entire interface. Some flocculent matter was floating in the organic phase layer. After shaking, the extracted contaminants were mostly in granular form; after about 240 hours of operation, the interface contaminants grew to a thickness of about 7-10 cm, and their color and shape were more consistent with before.

[0069] Particle size analysis of interface contaminants samples revealed that within 240 hours of extraction column operation, the particle size (D50) of the generated interface contaminants was primarily between 60 and 70 μm. Infrared analysis of the interface contaminants indicated a complex formation mechanism, suggesting that the main components are likely complex compounds and solid particles formed from degradation products of the tributyl phosphate (TBP) extractant. Operational experiments using this equipment can effectively generate interface contaminants during the extraction process, providing technical support for understanding the formation mechanism of contaminants and for process improvement.

[0070] This invention provides an experimental apparatus and method for studying interfacial contaminants with real-time monitoring capabilities. The formation process of interfacial contaminants is directly observed through a transparent lower expansion section, and the contaminants are extracted via sampling tubes on the lower expansion section for composition and structural analysis. Real-time monitoring of the stability of the pulsed column operation is achieved through real-time image analysis of the liquid flow within the column. The formation of interfacial contaminants over long periods is realized through extraction, back-extraction, and washing cycles, while simultaneously enabling the recycling of organic phases and radioactive materials on an industrial scale, reducing their loss. In summary, the apparatus and method for studying interfacial contaminants provided by this invention enable better understanding and control of interfacial contaminant generation, thereby improving the efficiency and quality of the liquid-liquid extraction process. Furthermore, the method utilizes recyclable feed solutions, effectively reducing the economic cost of the experiment and meeting the requirements of environmental protection and sustainable development.

[0071] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention is also intended to include these modifications and variations.

Claims

1. An experimental method for studying interfacial contaminants, the method being based on an experimental apparatus for studying interfacial contaminants with real-time monitoring capabilities, the apparatus comprising an extraction column (1), a lower expansion section (4), a back-extraction column (2), and an organic phase washing column (3), wherein the extraction column (1) is used to separate and extract metal ions from the feed solution to realize the extraction process; the lower expansion section (4) is used to observe and sample the interfacial contaminants formed in the extraction column (1) in real time; the back-extraction column (2) is used to back-extract metal ions from the organic phase back into the aqueous feed solution; and the organic phase washing column (3) is used to wash down the decomposition products and contaminants in the organic phase to realize the purification and reuse of the organic phase; The aqueous phase of the extraction column (1) is the feed liquid to be extracted, and the organic phase is the extractant; the aqueous phase of the back-extraction column (2) is the back-extraction agent, and the organic phase is the organic phase overflow of the extraction column (1); the aqueous phase of the organic phase washing column (3) is the aqueous phase washing agent, and the organic phase is the organic phase overflow of the back-extraction column (2); the organic phase overflow of the organic phase washing column (3) is returned to the extractant of the extraction column (1); The lower expansion section (4) is connected to the two-phase interface of the extraction column (1) through a connecting pipe. The interface contaminants in the extraction column (1) are drawn into the lower expansion section (4) by a feed pump. The interface contaminants accumulate in the lower expansion section (4). A pulse tube is provided at the lower end of the extraction column (1), the back-extraction column (2) and the organic phase washing column (3), and the other end of the pulse tube is connected to an air pulse generator to provide pulse vibration. The method includes the following steps: S1. Prepare the required experimental solution, extractant, back-extraction agent and aqueous washing agent, and adjust the feed flow rate of each solution to the set value; S2. The extraction column (1) is filled with extractant, the back-extraction column (2) is filled with back-extraction agent, and the organic phase washing column (3) is filled with aqueous washing agent. S3. After the column filling is completed, adjust the pulse amplitude of the extraction column (1), the back-extraction column (2) and the organic phase washing column (3), and set the interface value of the extraction column (1), the back-extraction column (2) and the organic phase washing column (3) so that the extraction column reaches the stable operating conditions. S4. The feed liquid of the extraction column (1) is transported into the extraction column (1). As the extraction process is running stably, interface contaminants are generated at the two-phase interface of the extraction column (1). The growth process of the interface contaminants is observed through the upper clarification section. The interface contaminants in the upper clarification section are sampled for analysis of their composition and structure.

2. The experimental method for studying interface contaminants according to claim 1, characterized in that, The extraction column (1) has a two-section structure with a coarser upper section and a finer lower section. The upper section is provided with an aqueous phase inlet and an organic phase outlet, while the lower section is provided with an organic phase inlet and an aqueous phase outlet near the bottom. The liquid to be extracted enters the extraction column (1) through the aqueous phase inlet on the upper section and flows downward. The extract enters the extraction column (1) through the organic phase inlet on the lower section and flows upward, generating interface contaminants at the two-phase interface. The organic phase overflow liquid of the extraction column (1) is a loaded organic phase and flows out from the organic phase outlet.

3. The experimental method for studying interface contaminants according to claim 2, characterized in that, The top of the lower enlarged section (4) is positioned higher than the top of the extraction column (1).

4. The experimental method for studying interface contaminants according to claim 3, characterized in that, The upper end of the lower enlarged section (4) has an interface contaminant inlet and an organic phase outlet, and the lower end has a raffinate aqueous phase outlet. The interface contaminant inlet is connected to the two-phase interface in the extraction column (1), the organic phase outlet is connected to the organic phase inlet of the extraction column (1), and the raffinate aqueous phase flows out from the raffinate aqueous phase outlet.

5. The experimental method for studying interfacial contaminants according to any one of claims 2-4, characterized in that, The back-extraction column (2) has a three-section structure that is thick at both ends and thin in the middle. The upper section has an aqueous phase inlet and an organic phase outlet, and the lower section has an organic phase inlet and an aqueous phase outlet. The back-extractant enters the back-extraction column (2) through the aqueous phase inlet and flows downward, and flows out from the aqueous phase outlet. The overflow liquid of the loaded organic phase of the extraction column (1) enters the back-extraction column (2) through the organic phase inlet and flows upward, thereby back-extracting the metal ions in the loaded organic phase back into the back-extractant. The loaded organic phase after back-extraction becomes an organic-poor phase and flows out from the organic phase outlet.

6. The experimental method for studying interface contaminants according to claim 5, characterized in that, The organic phase washing column (3) has a three-section structure that is thick at both ends and thin in the middle. The upper section has an aqueous phase inlet and an organic phase outlet, and the lower section has an organic phase inlet and an aqueous phase outlet. The lean organic phase flowing out from the back-extraction column (2) enters the organic phase washing column (3) through the organic phase inlet and flows upward. The aqueous washing liquid enters the organic phase washing column (3) through the aqueous phase inlet and flows downward to wash and purify the lean organic phase. After washing and purification, the lean organic phase flows out from the organic phase outlet and returns to the extract, thus realizing the recycling of the extract.

7. The experimental method for studying interface contaminants according to claim 6, characterized in that, In the organic phase washing column (3), the organic phase is washed by adding an appropriate amount of detergent and adjusting the appropriate temperature and pressure conditions.

8. The experimental method for studying interface contaminants according to claim 1, characterized in that, The extraction column (1) is equipped with a pulse baffle, and the back-extraction column (2) and the organic phase washing column (3) are equipped with sieve plates to enhance the contact and mixing between the two liquids, thereby improving the extraction efficiency.

9. The experimental method for studying interface contaminants according to claim 8, characterized in that, The extraction column (1), the lower expansion section (4), the back-extraction column (2) and the organic phase washing column (3) are made of high borosilicate glass and are covered with a transparent explosion-proof film reinforcement layer.

10. The experimental method for studying interface contaminants according to claim 9, characterized in that, Air blowing pipes and pressure monitoring sensors are installed at different column heights in the extraction column (1), back-extraction column (2), and organic phase washing column (3) to monitor the operational stability of the pulse column and the stability of the liquid flow inside the column in real time.

11. The experimental method for studying interface contaminants according to claim 10, characterized in that, Step S2 also includes turning on the air compressor and starting the air blowing pressure measurement to conduct online measurement of hydraulic performance.

12. The experimental method for studying interfacial contaminants according to any one of claims 7-11, characterized in that, In step S3, the pulse frequency and compressed air source pressure of the extraction column (1), back-extraction column (2), and organic phase washing column (3) are adjusted so that the pulse amplitude reaches the set value.

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