Gradient elution and double-mode intelligent end-point determination method for stepwise elution of vanadium and gallium in alkaline system

Abstract

The application discloses a gradient control washing and double-mode intelligent end point discrimination method for step-by-step elution of vanadium and gallium in an alkaline system, realizes selective elution of gallium through a plurality of gradient sulfuric acid solutions, realizes special elution of vanadium through an NH4Cl solution, and adopts atomic absorption spectrometry (AAS) and surface enhanced Raman spectroscopy (SERS) double-mode online monitoring, realizes rapid quantitative monitoring in a high-concentration section and realizes molecular specificity end point discrimination in a low-concentration section, so that precise end point discrimination of two-step elution of gallium and vanadium is completed, and problems, such as difficulty in judging the elution end point in the traditional gallium and vanadium step-by-step elution process, serious matrix interference of strong acid and high salt, easy over-washing or incomplete elution, and low automation level, are solved. The application can significantly improve the separation efficiency of gallium and vanadium and the purity of gallium products, reduce acid consumption and waste liquid discharge, realize full-process automation and intelligent operation, is suitable for gallium extraction processes of various alkaline gallium-containing solutions, and has strong industrial applicability.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgy and gallium extraction technology in alkaline systems, specifically to a gradient controlled elution and dual-mode intelligent endpoint determination method for stepwise elution of gallium and vanadium in an alkaline system. Background Technology

[0002] Gallium (Ga) and vanadium (V) play irreplaceable roles in semiconductors, new energy batteries, and high-temperature alloys. However, they often coexist in alkaline industrial waste liquids (such as the mother liquor from the Bayer process for aluminum extraction), with low concentrations (Ga: 200-400 mg / L, V: 100-150 mg / L), similar ionic forms (both exist as anions or hydroxyl complexes), and high separation difficulty. Traditional solvent extraction methods suffer from problems such as long processes, high reagent consumption, and emulsification risks.

[0003] In recent years, functional resin adsorption has attracted attention due to its high selectivity and ease of operation. In the alkaline system gallium extraction process, gallium is usually adsorbed by ammonia oxime resin in the form of hydroxygamate. Impurities such as vanadium are co-adsorbed with gallium, so the subsequent elution process needs to achieve efficient and precise separation of vanadium and gallium. Industrially, a process of eluting vanadium and gallium with 1-2 mol / L dilute sulfuric acid is often used, but it has many shortcomings in practical applications: traditional elution often uses sulfuric acid of single acidity, which easily leads to weak selective separation of gallium and vanadium, incomplete vanadium elution, or premature gallium loss; the elution endpoint often relies on manual experience, conductivity detection, or single instrument detection, which is prone to signal drift, insufficient sensitivity, and poor stability under strong acid, high salt, and complex matrices; traditional detection methods can only reflect the total element content and are difficult to achieve specific identification at the molecular structure level, which can easily lead to endpoint misjudgment; incomplete vanadium elution will directly affect the purity of gallium products and limit the subsequent preparation of high-purity gallium; the overall process has a low degree of automation, which is difficult to meet the needs of continuous, stable, and efficient industrial production. Currently, there is still a lack of a vanadium and gallium stepwise elution and endpoint determination technology that is versatile, precise in elution, stable in endpoint determination, strong in anti-interference ability, and highly automated. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a gradient-controlled elution and dual-mode intelligent endpoint determination method for the stepwise elution of vanadium and gallium in an alkaline system. Through gradient acid elution, dual-mode online monitoring, and intelligent endpoint determination, it achieves efficient separation of vanadium and gallium, precise controlled elution, stable endpoint determination, and fully automated operation of the entire process.

[0005] This invention provides a gradient-controlled elution and dual-mode intelligent endpoint determination method for stepwise elution of vanadium and gallium in an alkaline system, comprising the following steps: (1) Co-adsorption: The alkali-activated ammonia oxime resin is contacted with an alkaline gallium-containing solution with a pH of 13-14, so that gallium and vanadium are simultaneously adsorbed on the resin to complete the co-adsorption of gallium and vanadium; wherein the gallium concentration is 200-400 mg / L and the vanadium concentration is 100-150 mg / L. (2) Selective elution of gallium: The loaded resin is eluted stepwise with a multi-stage gradient sulfuric acid solution with a concentration of less than 0.7 mol / L, so that gallium is converted into gallium sulfate and vanadium is retained on the resin; (3) Specific vanadium washing: After gallium elution is completed, the NH4Cl solution is automatically switched to specifically elute vanadium to generate ammonium vanadate, so that vanadium enters the solution in the form of ammonium vanadate, thereby achieving efficient separation and separate collection of gallium and vanadium; (4) Dual-mode online monitoring and intelligent shutdown: During gallium and vanadium washing, AAS-SERS (atomic absorption spectroscopy-surface enhanced Raman spectroscopy) dual-mode collaborative detection is implemented to replace the traditional single detection mode. ASS is responsible for "precise measurement of constant concentration", and SERS is responsible for "precise identification of trace residues". When the concentration of the target metal ion is higher than 1 mg / L, atomic absorption spectroscopy (AAS) is used for real-time quantification; when the concentration drops to 1 mg / L, it automatically switches to surface enhanced Raman spectroscopy (SERS) to monitor the characteristic peak of gallium sulfate or the fingerprint peak of ammonium vanadate derivative complex; if the intensity of the characteristic peak is lower than the background noise for multiple consecutive scans and remains stable, it is determined that the corresponding metal has been completely eluted, and the system automatically terminates the elution of this stage and switches to the next process.

[0006] Furthermore, the methine oxime resin is activated with 0.5-1.0 mol / L NaOH solution for 1-2 hours before use.

[0007] Furthermore, the multi-gradient sulfuric acid solution achieves gentle elution and deep removal of gallium without desorbing vanadium from the resin.

[0008] The first step, with a concentration range of 0.5-0.6 mol / L, is used for gentle gallium elution. This concentration slowly disrupts the oxygen atom coordination between gallium and the amylopectin resin (Ga is adsorbed only through the C=NOH oxygen atom of the amylopectin group), causing the gallium ions adsorbed on the resin surface to gradually desorb and convert into gallium sulfate. This avoids damage to the resin structure caused by high-concentration sulfuric acid and does not lead to the desorption of vanadium ions from the resin, ensuring elution selectivity. The second step, with a concentration range of 0.6-0.7 mol / L, is used for deep gallium removal. For the small amount of strongly adsorbed gallium ions remaining on the resin after the first step, the desorption driving force is enhanced by appropriately increasing the sulfuric acid concentration, achieving complete gallium elution. At the same time, the concentration is strictly controlled not to exceed 0.7 mol / L to prevent premature desorption of vanadium ions and ensure the separation effect of gallium and vanadium.

[0009] Furthermore, SERS specifically identifies the molecular characteristic peaks of gallium sulfate and ammonium vanadate, respectively, unaffected by strong acids, high salts, and complex matrices. The characteristic peak of gallium was obtained by adding 8-hydroxyquinoline to the eluent to generate a Ga-8-HQ complex, and its peak at 1580 cm⁻¹ was monitored. -1 The nearby aromatic skeleton vibration peaks and the V=O end group symmetric stretching peak of ammonium vanadate are located at 925-936 cm⁻¹. -1 .

[0010] Furthermore, AAS is used for high-concentration process monitoring, and SERS is used for low-concentration endpoint discrimination. The two work together to achieve stable and accurate endpoint discrimination. The dual-mode switching threshold is that the metal ion concentration measured by AAS is ≤1 mg / L.

[0011] Furthermore, an intelligent control system enables automatic switching of eluent, automatic adjustment of flow rate and acidity, and automatic termination of elution at the endpoint, forming a closed-loop intelligent control system for the entire process. The endpoint is determined when the V=O end-group symmetric stretching peak of ammonium vanadate is in the 925-936 cm⁻¹ range during SERS-dominated monitoring. -1 If the intensity is below the background noise and remains stable for 15 consecutive seconds (5 scans with a 3-second interval between each scan), then gallium elution is considered complete.

[0012] The present invention also provides an intelligent control device for the method, including a resin exchange column, a gradient dilute sulfuric acid supply unit, a concentrated sulfuric acid supply unit, an automatic switching valve, an AAS online monitoring unit, a SERS monitoring unit, and an intelligent controller, to realize the fully automated operation of the gallium and vanadium stepwise elution process.

[0013] The method provided by this invention can be applied to the recovery of gallium and vanadium from Bayer process mother liquor, red mud leachate, or fly ash alkaline extract.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) High selectivity separation: Ga / V effective stepwise desorption was achieved through alkali activation and synergistic gradient acid washing.

[0015] (2) Intelligent control: The AAS-SERS dual-mode online monitoring system takes into account both wide linear range and ultra-high sensitivity, and achieves accurate identification of ppb-level residual metals. The dual-mode monitoring has complementary advantages and can effectively overcome the interference caused by strong acid, high salt and complex matrix. SERS achieves molecular-specific recognition, accurate and stable endpoint interpretation without obvious drift, and precise control of elution endpoint, reducing overwashing and ineffective acid consumption, and reducing acid consumption and waste liquid discharge.

[0016] (3) Strong engineering applicability: The whole process is automated and intelligent, reducing manual intervention, improving production stability and efficiency, with a wide range of applications. It is compatible with a variety of alkaline gallium-containing liquid systems and is easy to modify and implement on existing gallium extraction devices.

[0017] (4) Green and environmentally friendly: No organic solvents are required throughout the process, reducing secondary pollution. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the stepwise elution of vanadium and gallium and the dual-mode intelligent endpoint determination process in the alkaline system described in this invention.

[0019] Figure 2 The graph shows the adsorption rates of Ga and V at different pH values.

[0020] Figure 3 This is a elution distribution diagram of V and Ga during gradient elution.

[0021] Figure 4 This is a schematic diagram of the switching between AAS and SERS signals.

[0022] Figure 5 For comparison of the elution curves of Comparative Example 2 and the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0024] Example 1: Gradient sulfuric acid elution of vanadium and dual-mode endpoint determination The alkaline feed solution had a pH of 13-14, with gallium (Ga) concentrations of 200-400 mg / L and vanadium (V) concentrations of 100-150 mg / L. After activation with 1 mol / L sodium hydroxide at 25±5℃ for 1.5 hours, the ammonia oxime resin was fully adsorbed in the feed solution, achieving a gallium adsorption efficiency of 95%-98% and a vanadium adsorption efficiency of 90%-95%. This simultaneous enrichment of Ga and V provided a basis for subsequent separation, demonstrating the strong affinity of ammonia oximes for high-valence metals, especially Ga. 3+ and VO 2+ / VO3 + It exhibits good adsorption performance and can effectively achieve the initial separation of target metal ions from other impurity ions in the feed solution.

[0025] A high pH environment ensures that gallium exists in a stable [Ga(OH)4] state. - The presence of vanadium in this form facilitates its recognition and adsorption by amine oxime groups; under these conditions, vanadium mainly exists as H2VO4. - or VO4 3- It exists in anionic form and may also partially form polymers; the amine oxime resin can maintain structural stability under strong alkalinity and enhance its coordination ability through alkali activation.

[0026] The surface functional groups of the amylopectin resin after alkali activation treatment increase the deprotonation degree of amylopectin (=NOH), enhancing its affinity for metal ions (especially Ga). 3+ VO 3+ The coordination ability of species can remove impurities or oxidation products that may be adsorbed during storage.

[0027] This embodiment adopts a step-by-step strategy of first extracting gallium and then vanadium. The core reason for this is that Ga... 3+ It only coordinates with the oxygen atom (C=NOH) of the amylide oxime group, resulting in weak binding and easy elution by low-concentration acid; V 5+ It coordinates with the nitrogen atom (C-NH2) + oxygen atom (C=NOH) of the oxime group at two sites, forming a strong bond that is extremely difficult to be eluted by conventional acid.

[0028] The gallium elution stage employs a two-stage gradient sulfuric acid stepwise control: The first step involves using 0.5-0.6 mol / L dilute sulfuric acid, controlling the elution flow rate at 0.8 BV / h, and the elution temperature at 35℃ for gentle rinsing to remove non-specifically adsorbed alkali metal ions (Na+). + Light metal ions or other impurities are removed to maintain the integrity of the resin structure and prevent damage to functional groups caused by sudden acid shock.

[0029] The second step involves selectively eluting gallium with 0.6-0.7 mol / L dilute sulfuric acid, maintaining an elution flow rate of 0.8 BV / h and an elution temperature of 35°C to provide adequate acidity and destroy Ga. 3+ Gallium coordinates with the oxygen atom (C=NOH) of the oxime group, and enters the solution in the form of gallium sulfate. The gallium elution rate is ≥90%, while vanadium is basically not desorbed and the vanadium loss is <2%.

[0030] The elution process employs dual-mode online monitoring: AAS (Atomic Absorption Spectrometry) testing offers strong resistance to strong acid interference and high quantitative accuracy (relative standard deviation ≤2%), accurately capturing the stepwise changes in vanadium ion concentration and the abrupt changes in gallium ion concentration during gradient acid elution, aligning with the concentration characteristics of stepwise elution. However, it lacks sufficient capability for trace detection. SERS (Surface Enhanced Raman Spectrometry), on the other hand, exhibits strong resistance to interference (ignoring interference from sulfate ions and resin debris), high sensitivity for trace detection, and fast response speed, accurately capturing abrupt changes in ion concentration at the endpoint, compensating for AAS's limitation in the trace range. The combined use of both methods achieves stable and accurate endpoint determination. Therefore, in the high-concentration range (target metal ion concentration ≥1 mg / L), AAS is used to monitor gallium concentration changes, as this method offers rapid response, a wide linear range, and is suitable for principal component quantification.

[0031] The characteristic peak of gallium sulfate was monitored by switching SERS in the low-concentration endpoint region (target metal ion concentration < 1 mg / L). This was achieved by adding 8-hydroxyquinoline to the eluent to generate a Ga-8-HQ complex, and its peak at 1580 cm⁻¹ was monitored. -1 Nearby aromatic skeleton vibration peaks are used to determine the residue level.

[0032] Once the characteristic peaks of gallium sulfate disappear and remain stable, gallium elution is considered complete, and the system automatically switches to the NH4Cl elution step. The combination of these two methods achieves a transition from "macro-level concentration monitoring" to "molecular fingerprint recognition," significantly improving the accuracy of endpoint determination.

[0033] Vanadium elution with NH4Cl and two-mode endpoint determination In Example 1, after gallium was eluted from the alkaline vanadium-containing solution, vanadium on the resin was specifically eluted using a 1.5 mol / L NH4Cl solution at a flow rate of 0.7 BV / h and a temperature of 20°C. Vanadium entered the eluent in the form of ammonium vanadate. After elution, the vanadium concentration in the eluent and the amount of vanadium residue on the resin were measured, and the vanadium elution rate was calculated to be ≥95%.

[0034] During elution, in the high-concentration range (vanadium ion concentration > 1 mg / L), the AAS was switched to vanadium ion detection mode (wavelength 318.4 nm) to monitor the vanadium concentration trend in real time. The SERS was in standby mode, and the symmetric stretching of the V=O end group of ammonium vanadate in the 925-936 cm⁻¹ range was monitored simultaneously. -1 Vibrational peaks, and gallium sulfate-related 1580 cm⁻¹ -1 The nearby aromatic framework vibrational peaks showed no response, confirming the absence of secondary gallium leakage. In the low-concentration endpoint region (vanadium ion concentration < 1 mg / L), SERS detected a peak at 925-936 cm⁻¹. -1 The characteristic peak intensity was lower than the background noise for 5 consecutive scans (each scan interval was 3s, i.e., 15s in total) and remained stable. At the same time, the AAS detected a vanadium ion concentration of ≤0.5 mg / L and no gallium ion response for 30 consecutive seconds, indicating that vanadium elution was complete and the elution automatically ended.

[0035] Example 2: Resin Cyclic Stability Test The entire process of Example 1 was repeated 10 times, and the adsorption and elution rates of Ga and V were recorded in each cycle. The results showed that during the 10 cycles, the Ga adsorption rate remained at 94.5%-98.0%, and the elution rate remained at 95.0%-96.8%; the V adsorption rate remained at 89.5%-95.0%, and the elution rate remained at 95.8%-97.0%; and in each cycle, the purity of vanadium and gallium separation was ≥99.0%, with no obvious cross-contamination, no damage or clumping of the resin appearance, and no significant attenuation of adsorption-elution performance (fluctuations in adsorption rate and elution rate were both ≤3%).

[0036] The above test results show that the amylopyroxime resin used in this scheme can be reused for co-adsorption and stepwise elution of gallium and vanadium after regeneration. Combined with the AAS-SERS dual-mode synergistic detection process, it has good long-term operational stability and repeatability, which can reduce the resin replacement cost in industrial production, improve the economic efficiency and practicality of the process, and meet the needs of large-scale continuous production.

[0037] Comparative Example 1: Resin that has not undergone alkali activation was used directly. Except for the lack of activation treatment with 0.5-1.0 mol / L NaOH solution for the ammonia oxime resin, all other experimental parameters were completely consistent with those in Example 1. The experiment was repeated 3 times, and the adsorption and elution rates of gallium and vanadium were recorded, and the separation purity was detected. The experiment found that the saturated adsorption capacity of Ga in the unactivated resin was ≤10 mg / g, which was much lower than the 28.28 mg / g of the activated resin of this invention, indicating a significant decrease in adsorption capacity. The adsorption selectivity for V was improved, with a Ga / V adsorption ratio of ≈1:0.8, while the Ga / V adsorption ratio after activation in this invention was ≈3.16:1. Comparative Example 1 could not achieve selective adsorption of Ga. The total elution rate of Ga was ≤50%, with a large amount of Ga remaining on the resin surface, indicating poor elution effect. After 3 cycles of resin recycling, the adsorption capacity dropped sharply to ≤3 mg / g, which was much lower than the 15.73 mg / g after 10 cycles of this invention, indicating extremely poor cycle stability.

[0038] This indicates that alkaline activation of the amylopyroxime resin is key to improving Ga adsorption capacity, enhancing Ga / V adsorption selectivity, ensuring elution efficiency, and ensuring resin recyclability. Unactivated resin cannot achieve efficient separation and recovery of Ga / V.

[0039] Comparative Example 2: Single-stage elution using a single acidity After the alkali activation of the amine oxime resin with the same parameters as in Example 1, gallium and vanadium co-adsorption was performed (parameters were the same as in Example 1). After co-adsorption was completed, vanadium and gallium were eluted in one step with 1.5 mol / L sulfuric acid solution without gradient switching. All other experimental parameters were the same as in Example 1. The experiment was repeated 3 times.

[0040] Experiments revealed that the single-elution rate of Ga was approximately 65%, far lower than the total Ga elution rate of ≥95% achieved by gradient elution in this invention. This indicates incomplete elution, leaving a large amount of Ga residue on the resin surface. Without a deep removal step, Ga residue at strong adsorption sites on the resin was ≥30%, failing to achieve deep Ga removal. During single-acidity elution, fluctuations in local acid concentration led to an early V desorption rate of approximately 8%, while the gradient elution of this invention resulted in an early V desorption rate of <4%, reducing the Ga / V separation efficiency. The acid impact during single-elution caused local pore shrinkage in the resin, reducing the Ga adsorption capacity to 12 mg / g after 5 cycles. In contrast, the gradient elution of this invention, being a gentler elution, maintained a Ga adsorption capacity of 15.73 mg / g after 10 cycles, demonstrating superior resin structural integrity.

[0041] The results show that using single-acidity sulfuric acid for one-time elution cannot achieve gentle elution and deep removal of Ga, which can easily lead to premature desorption of V, incomplete elution of Ga, and acid shock damage to the resin. In contrast, the multi-stage gradient sulfuric acid elution of the present invention can achieve efficient, selective, and gentle removal of Ga, ensuring the Ga / V separation effect and resin stability.

[0042] Comparative Example 3: Monitoring using only AAS The process parameters of Examples 1-2 were followed exactly. Only the AAS single detection module was used to monitor the elution process; the SERS detection module was not used. The endpoint was determined solely by the ion concentration detected by the AAS (criterion: target ion concentration ≤ 0.5 mg / L for 30 consecutive seconds). The experiment was repeated three times. It was found that the detection limit of AAS for low-concentration ions was ≥ 0.1 mg / L. When the Ga / V concentration in the eluent is <0.1 mg / L, AAS has no effective response and cannot achieve quantitative detection of trace ions. The SERS detection limit of this invention is ≤0.001 mg / L, which can accurately capture trace residues. When the ion concentration is <1 mg / L in the later stage of elution, the relative standard deviation (RSD) of AAS detection is ≥15%, and the quantitative accuracy is extremely poor. After switching to SERS detection, the RSD is ≤3%, and the quantitative accuracy is accurate. It cannot identify trace Ga / V residues (<0.1 mg / L) in the later stage of resin elution, which can easily lead to misjudgment of the elution endpoint, resulting in incomplete elution or excessive eluent. The dual-mode detection of this invention can accurately determine the elution endpoint and achieve precise control of the amount of eluent used. The trace amounts of residual V in the V eluent cannot be effectively monitored, resulting in a purity of ≤98% for the recovered V product. The dual-mode detection of this invention can achieve precise control of trace residues, and the purity of the V product can be ≥99.5%.

[0043] The results show that AAS spectroscopy alone cannot achieve accurate monitoring of high and low concentration ions in the eluent throughout the entire process. It has insufficient detection capability for low concentration / trace ions, which can easily lead to misjudgment of the elution endpoint and a decrease in product purity. However, the AAS-SERS dual-mode detection of the present invention can achieve full-process monitoring of "high concentration AAS quantification + low concentration SERS accurate identification", which greatly improves detection accuracy and product purity.

[0044] Although the above embodiments have described the present invention and its implementation in detail, it should be noted that for those skilled in the art, any changes, modifications, substitutions, combinations, simplifications, etc., made to the corresponding conditions without departing from the technical principles of the present invention should be considered as equivalent substitutions, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A gradient-controlled elution method and dual-mode intelligent endpoint determination method for stepwise elution of vanadium and gallium in an alkaline system, characterized in that, Includes the following steps: (1) Co-adsorption: The alkali-activated ammonia oxime resin is contacted with an alkaline gallium-containing solution with a pH of 13-14, so that gallium and vanadium are simultaneously adsorbed on the resin to complete the co-adsorption of gallium and vanadium; wherein the gallium concentration in the alkaline gallium-containing solution is 200-400 mg / L and the vanadium concentration is 100-150 mg / L. (2) Selective elution of gallium: The loaded resin is eluted stepwise with a multi-stage gradient sulfuric acid solution with a concentration of less than 0.7 mol / L, so that gallium is converted into gallium sulfate and vanadium is retained on the resin; (3) Specific vanadium washing: After gallium elution is completed, switch to NH4Cl solution for elution, so that vanadium enters the solution in the form of ammonium vanadate, thereby achieving efficient separation and separate collection of gallium and vanadium; (4) Dual-mode online monitoring and stop judgment: During gallium and vanadium washing, when the target metal ion concentration is higher than 1 mg / L, atomic absorption spectrometry (AAS) is used for real-time quantification; when the target metal ion concentration drops to no higher than 1 mg / L, surface-enhanced Raman spectroscopy (SERS) is used to monitor the characteristic peak of gallium sulfate or the fingerprint peak of ammonium vanadate derivative complex; if the intensity of the characteristic peak is lower than the background noise and remains stable for multiple consecutive scans, it is determined that the corresponding metal has been completely eluted, and the system automatically terminates the elution of this stage and switches to the next process.

2. The method according to claim 1, characterized in that, The amylopyroxime resin is activated with 0.5-1.0 mol / L NaOH solution for 1-2 hours before use.

3. The method according to claim 1, characterized in that, The multi-stage gradient sulfuric acid solution is used. In the first stage, the sulfuric acid concentration ranges from 0.5 to 0.6 mol / L for gentle gallium elution. In the second stage, the sulfuric acid concentration ranges from 0.6 to 0.7 mol / L for deep gallium removal, achieving gallium removal without desorbing vanadium from the resin.

4. The method according to claim 1, characterized in that, Surface-enhanced Raman spectroscopy (SERS) specifically identifies the molecular characteristic peaks of gallium sulfate and ammonium vanadate, respectively, unaffected by strong acids, high salts, and complex matrices. The characteristic peak of gallium was obtained by adding 8-hydroxyquinoline to the eluent to form a Ga-8-HQ complex, and its peak at 1580 cm⁻¹ was monitored. -1 The nearby aromatic skeleton vibration peaks and the V=O end group symmetric stretching peak of ammonium vanadate are located at 925-936 cm⁻¹. -1 .

5. The method according to claim 1, characterized in that, Atomic absorption spectroscopy (AAS) is used for high-concentration process monitoring, while surface-enhanced Raman spectroscopy (SERS) is used for low-concentration endpoint discrimination. The two work together to achieve stable and accurate endpoint discrimination. The dual-mode switching threshold is that the metal ion concentration measured by atomic absorption spectroscopy (AAS) is ≤1 mg / L.

6. The method according to claim 1, characterized in that, An intelligent control system enables automatic switching of eluent, automatic adjustment of flow rate, acidity and solution, and automatic termination of elution at the endpoint, forming a closed-loop intelligent control throughout the entire process. The endpoint is determined by the symmetric stretching peak of the V=O end group of ammonium vanadate in the 925-936 cm⁻¹ region during surface-enhanced Raman spectroscopy (SERS)-dominated monitoring. -1 If the intensity is below the background noise and remains stable for 15 consecutive seconds (5 scans with a 3-second interval between each scan), then gallium elution is considered complete.

7. An intelligent control device for use in the method of any one of claims 1-6, characterized in that, It includes a resin exchange column, a gradient dilute sulfuric acid supply unit, a concentrated sulfuric acid supply unit, an automatic switching valve, an atomic absorption spectroscopy (AAS) online monitoring unit, a surface-enhanced Raman spectroscopy (SERS) monitoring unit, and an intelligent controller, enabling fully automated operation of the gallium and vanadium stepwise elution process.

8. The method according to any one of claims 1-6, characterized in that, It can be applied to the recovery of gallium and vanadium from Bayer process mother liquor, red mud leachate or fly ash alkaline extract.

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