Efficient terbium recovery method based on pore throat microchannel

Abstract

The invention discloses an efficient terbium recovery method based on a pore throat microchannel, which specifically comprises the following steps: mixing an extraction agent P507, kerosene and Cyanex 272 to obtain an organic phase, taking a mixed solution of terbium, lanthanum and cerium ions as a water phase, and performing extraction separation of terbium ions under the condition of high water-oil ratio by using a serial pore throat structure microchannel. By regulating and controlling key parameters such as the volume ratio, the flow rate, the initial acidity of a water phase, the temperature, the phase ratio and the initial concentration of ions of the extraction agent, efficient selective separation of terbium, lanthanum and cerium in a mixed system is realized. Experimental results show that the separation coefficients of terbium lanthanum and terbium cerium in the mixed system respectively reach 103.28 and 21.33, the terbium ion extraction efficiency is 90.75%, and the mass transfer strengthening effect brought by the pore throat structure is shown. A complete technical path is provided for diversified separation of terbium resources in a high-phase-ratio system, and the method has the advantages of being easy and convenient to operate, remarkable in mass transfer strengthening effect, large in industrialization potential and the like.

Description

Technical Field

[0001] This invention belongs to the field of chemical process separation and purification technology, specifically relating to a method for efficient terbium recovery based on pore throat microchannels. Background Technology

[0002] Currently, traditional processes for terbium recovery generally suffer from high production costs, complex processes, and stringent equipment requirements, making it difficult to achieve efficient separation and purification of terbium. Even hydrometallurgy, the preferred technology, and its solvent extraction methods have significant shortcomings. Traditional solvent extraction often requires multiple stages of series operation to achieve full terbium recovery, resulting in high extractant consumption, cumbersome processes, and significantly higher operational difficulty and processing load compared to conventional scenarios.

[0003] Currently, research on the efficient recovery of pure terbium compounds in existing technologies remains relatively limited. Therefore, developing an environmentally friendly, efficient, and feasible new process for the recovery of pure terbium compounds, and overcoming the bottlenecks of existing technologies, is of significant research value and practical application importance for alleviating the pressure of terbium resource shortages and reducing application costs. Summary of the Invention

[0004] The purpose of this invention is to provide a highly efficient terbium recovery method based on pore throat microchannels. By using tandem pore throat microchannels to extract and separate terbium in a high-ratio system (R greater than 10:1), this method solves the problem of poor selectivity in the separation of terbium from lanthanum and cerium in mixed element systems, and provides an efficient technical path for the separation and recovery of rare and precious metals.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for efficient terbium recovery based on pore-throat microchannels includes the following steps: (1) Dissolve terbium chloride hexahydrate, lanthanum chloride heptahydrate and cerium chloride heptahydrate in deionized water, adjust the pH to acidic, and obtain a terbium-lanthanum-cerium ion mixed solution with a final concentration of 50~200 mg / L as the aqueous phase; (2) The organic phase was obtained by mixing extractant P507, kerosene and Cyanex 272; (3) The aqueous phase obtained in step (1) and the organic phase obtained in step (2) are extracted at room temperature through a series of pore throat microchannels at a certain volume flow rate. The outlet of the pore throat microchannel is connected to a polytetrafluoroethylene tube to introduce the fluid into a separatory funnel. After the separation is complete, the ion concentration in the raffinate is detected.

[0006] Furthermore, the pH range mentioned in step (1) is 0.7 to 3.5.

[0007] Furthermore, in step (2), the amount of extractant P507 is 30-80% of the oil phase volume, the amount of Cyanex 272 is 5-10% of the oil phase volume, and the remainder is kerosene.

[0008] Furthermore, in step (3), the water-oil ratio of the aqueous phase to the organic phase is 10:1 to 50:1.

[0009] Furthermore, the certain volumetric flow rates mentioned in step (3) are 1000~3000 μl / min and 60~300 μl / min, respectively.

[0010] Furthermore, the extraction time in step (3) is 9.0~112.9 s.

[0011] Furthermore, the structure of the series-connected pore-throat microchannel in step (3) includes a front part, a middle part and a rear part; the front part is a T-shaped microchannel, with two ports being the inlets of the aqueous phase and the organic phase, respectively, and the other port being connected to one port of the middle part through a throat, and the other port of the middle part being connected to one port of the rear part through a throat, and the other port of the rear part being the outlet of the extract phase and the raffinate phase.

[0012] The beneficial effects of this invention are as follows: This invention achieves efficient extraction and separation of terbium ions under high water-oil ratio conditions through a series-connected pore-throat microchannel structure. By controlling key parameters such as extractant volume ratio, flow rate, initial acidity of the aqueous phase, temperature, phase ratio, and initial ion concentration, highly efficient selective separation of terbium from lanthanum and cerium in a terbium-lanthanum-cerium mixed system is achieved. Experimental results show that the separation coefficients of terbium and lanthanum and terbium and cerium in the mixed system reach 103.28 and 21.33, respectively, and the terbium ion extraction efficiency is 90.75%, indicating the mass transfer enhancement effect brought about by the pore-throat structure. This invention provides a complete technical route for the diversified separation of terbium resources in high phase ratio systems, with advantages such as simple operation, significant mass transfer enhancement effect, and great industrialization potential. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the experimental apparatus for extraction and separation at high phase ratio using a series of pore-throat microchannels according to the present invention.

[0014] Figure 2 This is a three-dimensional structural schematic diagram and a top view of the series-connected pore throat microchannel used in this invention. Detailed Implementation

[0015] The following detailed description and explanation of a research method for enhancing terbium recovery technology using pore throat microchannels provided by the present invention, with specific examples, will make the content of the present invention easier to understand, but the scope of protection of the present invention is not limited thereto.

[0016] Figure 1This is a schematic diagram of the experimental apparatus for extraction and separation at high phase using a series-connected pore-throat microchannel according to the present invention. The structure of the series-connected pore-throat microchannel includes a front part, a middle part, and a rear part. The front part is a T-shaped microchannel with two ports for the inlet of the aqueous phase and the inlet of the organic phase, respectively. The other port is connected to one port of the middle part through a throat. The other port of the middle part is connected to one port of the rear part through a throat. The other port of the rear part is the outlet of the extract phase and the raffinate phase.

[0017] In this study, the microextraction experimental system was constructed with a PTFE tube connecting the syringe pump, microchannel chip, and sample collection device. A precision syringe pump was used to pump a solution containing both aqueous and organic phases into the microchannel. The PTFE tube was used to guide the liquid flowing out of the microchannel into a separatory funnel. After the two phases were completely separated, samples were taken and analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES) to accurately determine data such as the extraction rate.

[0018] Figure 2 This is a schematic diagram of the series-connected pore throat microchannel used in this method. Table 1 shows the detailed dimensions of each component of the microchannel.

[0019] Table 1 Microchannel Dimensions

[0020] Example 1 1. Optimization of the volume of extractant P507 (1) Weigh out a certain amount of terbium chloride hexahydrate, lanthanum chloride heptahydrate and cerium chloride heptahydrate respectively, dissolve them in deionized water, and add hydrochloric acid to adjust the pH of the aqueous phase to 0.7, so as to obtain a mixed solution of terbium, lanthanum and cerium ions with a concentration of 100 mg / L. (2) According to the volume ratio, measure the corresponding extractant P507 (30%~80%, respectively 30%, 40%, 50%, 60%, 70% and 80%) and diluent kerosene (the amount of kerosene is adjusted according to the extractant P507, and the sum of the two is 100%), and mix them evenly to obtain organic phase solutions with different extractant compositions. (3) At a water-to-oil ratio of 10:1, the 100 mg / L terbium, lanthanum and cerium ion mixed solution obtained in step (1) was used as the aqueous phase and the organic phase obtained in step (2) were extracted at room temperature (9.0~26.9 s) in a series pore throat microchannel at volume flow rates (1000~3000 μl / min and 100~300 μl / min, respectively). The outlet of the pore throat microchannel was connected to a polytetrafluoroethylene tube to introduce the fluid into a separatory funnel. After the separation was complete, the ion concentration in the raffinate was detected. The results are shown in Table 1.

[0021] Table 1. PI values ​​corresponding to different volumes of P507

[0022] Note: PI=E Tb ×β Tb / La ×β Tb / Ce E Tb Represents the extraction rate of terbium ions; β Tb / La The separation coefficient of terbium to lanthanum after extraction is represented by β. Tb / Ce The PI value represents the separation coefficient of terbium and cerium after extraction; the PI value is the average value at each flow rate.

[0023] The results showed that the optimal amount of extractant P507 was 60%, at which point the extraction performance index PI for terbium was 348.30. Subsequent experiments fixed the amount of extractant P507 at 60%.

[0024] 2. Optimization of Cyanex 272 size At room temperature, a mixed solution of terbium, lanthanum, and cerium ions with a concentration of 100 mg / L was prepared as the aqueous phase (pH=0.7) at a water-oil ratio of 10:1, using the same preparation method as step (1) in Example 1. The organic phase was prepared by mixing 60% P507, Cyanex 272 (0%, 5%, and 10%) and kerosene (determined based on the amount of Cyanex 272 added, with the total of the three being 100%). Extraction was performed in a series of pore-throat microchannels at volumetric flow rates of 1000–3000 μl / min and 100–300 μl / min, respectively (9.0–26.9 s). The outlet of the pore-throat microchannel was connected to a polytetrafluoroethylene tube to introduce the fluid into a separatory funnel. After complete separation, the ion concentration in the raffinate was measured. The results are shown in Table 2.

[0025] Table 2. PI values ​​corresponding to different Cyanex 272 volumes

[0026] Experimental results show that adding the co-extractant Cyanex 272 improves the extraction and separation performance, with the optimal dosage being 5%. The extraction performance index of the system for terbium is improved, with PI=778.25.

[0027] 3. Optimization of aqueous phase pH (1) Weigh out a certain amount of terbium chloride hexahydrate, lanthanum chloride heptahydrate and cerium chloride heptahydrate respectively, dissolve them in deionized water, and add hydrochloric acid to adjust the pH of the aqueous phase to 0.7~3.5 (increasing in increments of 0.7), and finally obtain a mixed solution of terbium, lanthanum and cerium ions with a concentration of 100 mg / L for all three. (2) An organic phase was prepared by mixing P507, Cyanex 272 and kerosene in an optimized volume ratio (60:5:35); (3) At a water-to-oil ratio of 10:1, the aqueous phase (100 mg / L) with different initial pH obtained in step (1) and the organic phase obtained in step (2) were extracted at room temperature (9.0 s) in a series pore throat microchannel at volume flow rates of 3000 μl / min and 300 μl / min, respectively. The outlet of the pore throat microchannel was connected to a polytetrafluoroethylene tube to introduce the fluid into a separatory funnel. After the separation was complete, the ion concentration in the raffinate was detected. The results are shown in Table 3.

[0028] Table 3. PI values ​​corresponding to pH values ​​of different terbium, lanthanum, and cerium ion mixed solutions

[0029] The results showed that the system exhibited the best extraction performance index for terbium at an initial aqueous phase pH of 0.7, with a PI of 1881.46.

[0030] 4. Optimization of dwell time A mixed solution of terbium, lanthanum, and cerium ions, each with a concentration of 100 mg / L, was used as the aqueous phase (pH=0.7) at a water-to-oil ratio of 10:1. P507, Cyanex 272, and kerosene were prepared as the organic phase at an optimized volume ratio (60:5:35). Extraction was performed at room temperature in a series of pore-throat microchannels at flow rates of 1000–3000 μl / min and 100–300 μl / min, respectively, with residence times ranging from 9.0 to 169.4 s. The outlet of the pore-throat microchannel was connected to a polytetrafluoroethylene tube to guide the fluid into a separatory funnel. After complete separation, the ion concentration in the raffinate was measured. The results are shown in Table 4.

[0031] Table 4. PI values ​​corresponding to different dwell times

[0032] The results showed that the extraction and separation efficiency was optimal when the residence time was 9.0 s.

[0033] 5. Optimization of the water-oil ratio A mixed solution of terbium, lanthanum, and cerium ions, all at a concentration of 100 mg / L, was used as the aqueous phase (pH=0.7). P507, Cyanex 272, and kerosene were prepared as the organic phase using an optimized volume ratio (60:5:35). Extraction was performed at room temperature in a series of pore-throat microchannels at water-to-oil ratios of 10:1 to 50:1 (10:1, 20:1, and 50:1), with flow rates of 3000 μl / min and 60–300 μl / min respectively (residence time 56.5 s). The outlet of the pore-throat microchannel was connected to a polytetrafluoroethylene tube to guide the fluid into a separatory funnel. After complete separation, the ion concentration in the raffinate was measured. The results are shown in Table 5.

[0034] Table 5. PI values ​​for different water-oil ratios

[0035] 6. Optimization of aqueous phases with different ion concentrations (1) Weigh terbium chloride hexahydrate, lanthanum chloride heptahydrate and cerium chloride heptahydrate respectively, dissolve them in deionized water, and add hydrochloric acid to adjust the pH of the aqueous phase to 0.7, so as to obtain a mixed solution of terbium, lanthanum and cerium ions with concentrations of 50~200mg / L (50, 100, 150, 200mg / L); (2) An organic phase was prepared by mixing P507, Cyanex 272 and kerosene in an optimized volume ratio (60:5:35); (3) At a water-to-oil ratio of 10:1, the aqueous phases with different ion concentrations (50~200 mg / L, pH=0.7) obtained in step (1) and the organic phases obtained in step (2) were extracted at room temperature in a series of pore throat microchannels at volumetric flow rates (3000 μl / min and 300 μl / min, respectively) (residence time 29.1s).

[0036] Table 6. PI values ​​corresponding to different ion concentrations in water.

[0037] At various ion concentrations, the extraction efficiency of terbium ions reached 89.64%–96.45% within a residence time of 29.1 s. Tb / La Up to 31.20, β Tb / Ce With a maximum value of 14.35, it can effectively separate terbium / lanthanum and terbium / cerium.

[0038] In summary, under the optimal conditions described above, namely, P507, Cyanex 272, and kerosene were prepared as the organic phase in an optimized volume ratio of 60:5:35, with a water-to-oil ratio of 10:1, a terbium-lanthanum-cerium ion mixed solution concentration of 100 mg / L, and a residence time of 9 s, the separation coefficients of terbium-lanthanum and terbium-cerium in the mixed system reached 103.28 and 21.33, respectively, and the terbium ion extraction efficiency was 90.75%.

[0039] Comparative Example 1 The experimental setup for this comparative example is similar to that of Example 1, except that a pore throat microchannel is not used; only a conventional extraction method (separating funnel) is employed.

[0040] The results showed that in conventional extraction experiments, under the same initial pH conditions for both organic and aqueous phases optimized using microextraction experiments, a residence time of 120 s was required to achieve a terbium ion extraction rate of 87.76%, corresponding to a separation coefficient β. Tb / La β Tb / CeThe values ​​were 25.27 and 11.00, respectively; under high ratio conditions (R=10:1~50:1), the terbium ion extraction efficiency of conventional extraction was at a relatively low level of 39.60%~58.79%, and the extraction performance index was relatively poor at R=50 (PI=E). Tb ×β Tb / La ×β Tb / Ce =0.396×39.82×9.31=146.81); at various ion concentrations (50~200 mg / L), the extraction rate of terbium ions was 27.30%~87.68%, β Tb / La Highest 9.07, β Tb / Ce The highest value was 4.31, indicating poor separation performance.

[0041] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for efficient terbium recovery based on pore-throat microchannels, characterized in that: Includes the following steps: (1) Dissolve terbium chloride hexahydrate, lanthanum chloride heptahydrate and cerium chloride heptahydrate in deionized water, adjust the pH to acidic, and obtain a terbium-lanthanum-cerium ion mixed solution with a final concentration of 50-200 mg / L as the aqueous phase; (2) The organic phase was obtained by mixing extractant P507, kerosene and Cyanex 272; (3) The aqueous phase obtained in step (1) and the organic phase obtained in step (2) are extracted at room temperature through a series of pore throat microchannels at a certain volume flow rate. The outlet of the pore throat microchannel is connected to a polytetrafluoroethylene tube to introduce the fluid into a separatory funnel. After the separation is complete, the ion concentration in the raffinate is detected.

2. The recycling method according to claim 1, characterized in that: The pH range mentioned in step (1) is 0.7 to 3.

5.

3. The recycling method according to claim 1, characterized in that: In step (2), the amount of extractant P507 is 30-80% of the oil phase volume, the amount of Cyanex 272 is 5-10% of the oil phase volume, and the remainder is kerosene.

4. The recycling method according to claim 1, characterized in that: In step (3), the ratio of water to oil in the aqueous phase to the organic phase is 10:1 to 50:

1.

5. The recycling method according to claim 1, characterized in that: The specific volumetric flow rates mentioned in step (3) are 1000~3000 μl / min and 60~300 μl / min, respectively.

6. The recycling method according to claim 1, characterized in that: The extraction time in step (3) is 9.0~112.9 s.

7. The recycling method according to claim 1, characterized in that: The structure of the series-connected pore-throat microchannel in step (3) includes a front part, a middle part and a rear part; the front part is a T-shaped microchannel with two ports being the inlets of the aqueous phase and the organic phase, respectively, and the other port is connected to one port of the middle part through a throat. The other port of the middle part is connected to one port of the rear part through a throat, and the other port of the rear part is the outlet of the extract phase and the raffinate phase.

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