Method and system for efficiently enriching and deeply purifying gallium from gallium-containing vanadium precipitate

Abstract

The invention discloses a method and a system for efficiently enriching and deeply purifying gallium from gallium-containing vanadium precipitates, and relates to the technical field of hydrometallurgy and comprehensive utilization of secondary resources. The method comprises the following steps: carrying out graded synergistic activation pretreatment on the gallium-containing vanadium precipitate, adding a temperature-sensitive leaching agent, selectively leaching gallium under a specific double-frequency pulse ultrasonic field, and carrying out heating sedimentation to realize primary separation and enrichment of gallium; then, dissolving the gallium-rich precipitate by adopting a reducing acid solution, pre-reducing impurity vanadium and adjusting the pH value of the solution while obtaining a crude gallium solution, and creating favorable conditions for deep purification; the crude gallium solution enters integrated multi-frequency ultrasound, impurities such as vanadium are deeply removed under optimized parameters, and a high-purity gallium solution is obtained; and finally, the impurity-containing enriched phase generated by purification is subjected to resourceful treatment, so that valuable metal recovery and material closed loop are realized. Through process coupling and system integration, high-selectivity extraction, deep purification and resource circulation of gallium are achieved, and the method has the advantages of being short in process and high in selectivity.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgy and comprehensive utilization of secondary resources. Specifically, it relates to a method and system for efficiently enriching and deeply purifying gallium from gallium-vanadium precipitates. Background Technology

[0002] Gallium is an important rare and dispersed metal widely used in semiconductors, optoelectronics, aerospace, and other fields. In nature, gallium rarely forms independent deposits; it is mainly found as a byproduct in resources such as bauxite, lead-zinc ore, and coal, and is recovered as a byproduct during smelting. During vanadium smelting, due to the similar chemical properties of gallium and vanadium, some gallium will accompany vanadium into precipitates or adsorbents, forming gallium-vanadium precipitates (such as iron vanadate precipitates, calcium vanadate precipitates, and vanadium adsorbate saturates).

[0003] Existing technologies for recovering gallium from gallium-vanadium precipitates are mainly based on hydrometallurgical processes, typically employing acid or alkali leaching. However, conventional methods have several inherent bottlenecks. First, the physical encapsulation structure is difficult to break; gallium is often tightly encapsulated or dissolved within the lattice of dense vanadium precipitate crystals. Traditional stirring leaching methods struggle to effectively break this encapsulation, resulting in insufficient gallium exposure and generally low leaching rates. Second, chemically selective separation is difficult; gallium and vanadium exhibit similar dissolution behaviors in acidic and alkaline solutions, making it difficult to avoid significant co-dissolution of vanadium with conventional leaching agents. This not only increases the difficulty and cost of subsequent solution purification but also reduces the gallium grade in the enrichment solution. Furthermore, the reaction kinetics are slow; the leaching process is controlled by solid-film diffusion, requiring long reaction times, high reagent concentrations, and high temperatures, leading to high energy and material consumption and low efficiency.

[0004] To overcome these difficulties, ultrasonic strengthening technology has been introduced into the field of hydrometallurgy. The localized high temperature, high pressure, and intense microjets generated by its cavitation effect help break down particles and enhance mass transfer. However, for the special system of gallium-vanadium precipitates, while ultrasonic strengthening alone can increase the overall dissolution rate of the metal, it often exacerbates the simultaneous dissolution of gallium and vanadium, resulting in limited selectivity improvement. Furthermore, high-intensity, long-duration single-frequency ultrasound can lead to excessive energy consumption and equipment wear. On the other hand, in the field of leaching chemistry, researchers have developed various selective complexing agents. However, traditional complexing agents typically require complex subsequent processes such as solvent extraction or ion exchange after leaching to achieve metal separation and reagent regeneration, resulting in lengthy process flows.

[0005] Furthermore, for the deep purification of gallium-enriched solutions, the main purification methods currently include solvent extraction, ion exchange, chemical precipitation, and electrolytic refining. Existing research has shown that ultrasound-assisted enhanced electrolytic extraction of metallic gallium can improve the reaction rate and current efficiency. The strong stirring effect of ultrasonic cavitation microjets on the solution reduces the thickness of the diffusion layer on the electrode surface and accelerates the detachment of hydrogen bubbles from the electrode surface. Another patent discloses a method for purifying metallic gallium, which uses ultrasonic vibration to separate metallic gallium from sponge gallium impurities during acid washing.

[0006] However, existing technologies still have the following shortcomings. First, most existing ultrasonic treatment devices are single-function devices, lacking system integration with reagent dosing, online monitoring, and intelligent control, making it difficult to achieve optimized control throughout the entire process. Second, most devices adopt a fixed frequency and fixed power design, which cannot optimize ultrasonic parameters in real time according to fluctuations in influent water quality, resulting in energy waste or unstable treatment effects. Third, gallium solutions have characteristics such as high density, high viscosity, and easy supercooling, making it difficult for conventional ultrasonic equipment to adapt to their special physical properties, leading to low treatment efficiency and high gallium loss rate. Fourth, existing technologies mostly rely on manual experience to adjust parameters, making it difficult to achieve precise control and stable operation. Summary of the Invention

[0007] One of the objectives of this invention is to provide a method for efficient enrichment of gallium-vanadium-containing precipitates, so as to achieve efficient, highly selective, and short-process recovery of gallium from complex gallium-vanadium-containing precipitates.

[0008] The second objective of this invention is to provide a method and system for deep purification of gallium, so as to achieve the purpose of deep purification of a highly enriched gallium solution obtained based on one of the objectives of this invention.

[0009] To achieve one of the objectives of this invention, the following technical means are employed: A method for efficient enrichment from gallium-vanadium precipitates includes the following steps: Gallium-vanadium precipitate was mixed with water to prepare a slurry, which was then subjected to chemical preactivation, filler implantation and coupling activation in sequence to obtain an activated precursor slurry. The temperature of the activated precursor slurry is controlled at 20~30℃, a temperature-sensitive leaching agent is added, and the mixture is mixed evenly to obtain a leaching slurry; the temperature-sensitive leaching agent is a copolymer with poly(N-isopropylacrylamide) as the temperature-sensitive segment and 8-hydroxyquinoline-5-sulfonic acid as the gallium chelating ligand connected by amide bonds. The ultrasonic reaction is initiated on the leachate slurry, and the ultrasonic field is controlled in a dual-frequency combination mode with a main frequency of 20~40kHz and an auxiliary frequency of 80~120kHz. The power ratio of the main frequency to the auxiliary frequency is 60~80%: 20~40%, the total power density is 300-500 W / L, the overall reaction temperature is maintained at 20~30℃, and the reaction time is 20~60 minutes. After the reaction is complete, the entire reaction system is heated to 35-45°C, and after standing, solid-liquid separation is performed to obtain gallium-rich precipitate and leaching tail liquid.

[0010] Thus, the key steps are clearly defined as pretreatment, temperature-sensitive leaching, specific ultrasonic field action, and temperature-increased separation. Specifically, ultrasonic reaction is performed below the critical dissolution temperature of the leaching agent, utilizing the expanded state of its temperature-sensitive segments to selectively complex gallium based on gallium chelate ligands. Under the synergistic effect of a specific dual-frequency ultrasonic field, instantaneous high temperatures are generated locally, controlling the expansion and retraction of the temperature-sensitive segments in the leaching agent. This allows the gallium chelate ligands to be exposed and chelate gallium in the expanded state, and to be isolated from the outside in the retracted state, enhancing leaching and mass transfer. Finally, a simple temperature increase triggers the extensive retraction and precipitation of the temperature-sensitive segments in the leaching agent, achieving highly selective in-situ separation of gallium.

[0011] Preferably, the chemical preactivation includes: Control the liquid-to-solid ratio of the slurry to 5-8 L / kg, adjust the pH to 3.5-5.5 with dilute sulfuric acid, add citric acid with a concentration of 0.2-0.8 mol / L, and react for 1.5-3 hours under stirring conditions of 40-60℃ and 50-100 rpm.

[0012] Citric acid selectively complexes and dissolves metal ions at the grain boundaries of vanadium precipitates under weakly acidic and mildly heated conditions, creating initial microcracks and diffusion channels on the precipitate surface, laying the structural foundation for subsequent steps to break the physical encapsulation of gallium.

[0013] Furthermore, the filler implantation includes: In the chemically pre-activated slurry, add carboxylated nano-silica with a particle size of 20-100 nm at 0.1%-0.5% by dry basis material mass, and disperse at 30-600 rpm for 10-15 minutes; Nitrogen microbubbles encapsulated in PLGA, comprising 0.5% to 2% of the total volume of the slurry, are bubbled into the slurry. The microbubbles have a particle size of 10 to 100 μm.

[0014] In this way, carboxylated nano-silica is used as a stress concentrater anchored at the crack formed after chemical pre-activation; nitrogen microbubbles encapsulated in PLGA are adsorbed at the interface as pre-set cavitation nuclei. The two work together to precisely guide the subsequent ultrasonic energy to the target location, achieving efficient energy utilization and ensuring that the subsequent ultrasonic action can accurately act on the surface of the gallium physically encapsulated precipitate.

[0015] Furthermore, the coupling activation includes: The slurry after the filler is implanted is maintained at 70~80℃ and 50~100 rpm for 20~30 minutes, and then cooled to the temperature required for adding the temperature-sensitive leaching agent to obtain the activated precursor slurry.

[0016] In this way, gentle heating promotes the formation of strong chemical bonds (such as MO-Si bonds) between nano-silica and the activated interface, and induces subcritical propagation of microcracks and stable adsorption of microbubbles. Ultimately, the effects of the first two steps are solidified into a structurally stable and functionally integrated activated precursor, ensuring the reproducibility of the pretreatment effect and compatibility with subsequent steps.

[0017] Furthermore, the temperature-sensitive leaching agent is prepared by the following steps: dissolving carboxyl-terminated poly(N-isopropylacrylamide) in anhydrous dimethyl sulfoxide, activating its terminal carboxyl group in the presence of carbodiimide and N-hydroxysuccinimide, and then subjecting it to an amidation coupling reaction with an amino derivative of 8-hydroxyquinoline-5-sulfonic acid. The reaction product is obtained after precipitation, washing, and drying.

[0018] This preparation method ensures that the poly(N-isopropylacrylamide) thermosensitive segment and the 8-hydroxyquinoline gallium chelate ligand are covalently linked by a stable amide bond, thereby endowing the leaching agent with reliable temperature-sensing switching characteristics and specific complexing ability for gallium ions.

[0019] Furthermore, the amount of the temperature-sensitive leaching agent added, based on the molar amount of the 8-hydroxyquinoline-5-sulfonic acid group in its structure, is 1.5 to 3.0 times the theoretical molar amount of gallium in the slurry.

[0020] By controlling the amount added, it is possible to ensure that there are sufficient effective chelating sites to fully react with gallium ions, while avoiding excessive waste of reagents.

[0021] Furthermore, the ultrasonic field adopts a pulse working mode, with a pulse working cycle of 2 to 5 seconds and an interval of 1 to 3 seconds.

[0022] Among them, the pulsed ultrasonic mode generates cavitation effect during the working period to promote the reaction, facilitates the diffusion of reactants and products during the intermittent period, and can effectively control the overall temperature rise of the reaction system, preventing the local temperature from exceeding the LCST of the leaching agent due to continuous ultrasonication and premature winding and closing.

[0023] Furthermore, during the ultrasonic process, sodium sulfite is added to the slurry at a concentration of 1-5 g / L.

[0024] Sodium sulfite, as a reducing agent, can reduce pentavalent vanadium in the slurry to tetravalent vanadium, thereby further inhibiting the co-dissolution of vanadium at the chemical level, and working synergistically with the selective leaching at the physical level.

[0025] Furthermore, during the heating process after the ultrasonic reaction, the reaction system is heated to 35-45°C within 2-5 minutes, and then allowed to stand at this temperature for 5-15 minutes before solid-liquid separation.

[0026] By rapidly heating the leaching agent to above its LCST, hydrophobic collapse and aggregation of its molecular chains can be triggered, promoting the rapid and complete precipitation of the gallium / leaching agent complex from the solution. Appropriate settling time is beneficial for the growth and aggregation of the precipitates, thereby improving the efficiency of subsequent solid-liquid separation.

[0027] Furthermore, the gallium-vanadium precipitate is one or more of iron vanadate, calcium vanadate, and vanadium adsorption saturated resin.

[0028] The present invention has the following beneficial effects when applied: First, a highly efficient and selective leaching and preliminary separation of gallium was integrated. Through chemical pre-activation, filler implantation, and coupled activation to disrupt the encapsulation structure and create a guiding path for ultrasound, a temperature-sensitive leaching agent was used to selectively complex gallium at low temperatures. This was further enhanced by dual-frequency combined ultrasound to strengthen the interfacial reaction and mass transfer. Finally, the target product could be separated in situ as a precipitate simply by raising the temperature. This synergistic mechanism enabled a high leaching rate for gallium, while suppressing the co-dissolution rate of vanadium, significantly improving leaching selectivity, and eliminating multiple intermediate steps such as traditional liquid-solid separation / solution purification.

[0029] Secondly, the traditional lengthy process of leaching, solid-liquid separation, solution enrichment, and purification is simplified into a shorter process of pretreatment, coupled leaching, and heated sedimentation. The temperature-sensitive leaching agent combines leaching and primary enrichment functions, and the initial enrichment of gallium can be achieved through temperature control, reducing equipment investment and operating units, and improving production efficiency.

[0030] Based on the aforementioned gallium-rich precipitates, due to the high gallium leaching rate, conventional purification methods are insufficient for deep purification.

[0031] Therefore, in order to achieve the second objective of this invention, the following technical means are adopted: A system for deep purification of gallium, comprising: An ultrasonic reaction unit includes a reaction cavity and a multi-frequency combined ultrasonic transducer array and a turbulence enhancement structure disposed within the reaction cavity. A precise drug dosing unit is connected to the ultrasonic reaction unit and is used to add pH adjuster and purifier to the ultrasonic reaction unit; An online monitoring unit is used to monitor the parameters of the gallium solution at the inlet and / or outlet of the ultrasonic reaction unit in real time; The intelligent control unit is electrically connected to the ultrasonic reaction unit, the precise drug dosing unit, and the online monitoring unit. It is used to optimize and control the ultrasonic parameters of the ultrasonic reaction unit and the drug dosing amount of the precise drug dosing unit based on the monitoring data of the online monitoring unit and the preset purification model.

[0032] Preferably, the multi-frequency combined ultrasonic transducer array includes at least one set of main frequency transducers and at least one set of auxiliary frequency transducers. The frequency range of the main frequency transducers is 20~40 kHz, and the frequency range of the auxiliary frequency transducers is 60~100 kHz. The power ratio of the main frequency to the auxiliary frequency is 60~80% for the main frequency and 20~40% for the auxiliary frequency.

[0033] In this way, the main low frequency generates a strong macroscopic cavitation effect, while the auxiliary high frequency generates a delicate microscopic cavitation effect. The combination of the two forms a broadband cavitation field, which is the key to achieving enhanced mass transfer and improved reaction efficiency.

[0034] Furthermore, the turbulence-enhancing structure is a spiral guide plate or a wave-shaped reflector plate disposed on the inner wall of the reaction chamber.

[0035] The flow and acoustic fields inside the reactor are optimized by using spiral guide plates or corrugated reflectors. Their function is to extend the solution residence time, eliminate dead zones, and enhance cavitation uniformity, thereby solving the problems of conventional equipment's inability to adapt to the physical properties of gallium solutions and its low processing efficiency.

[0036] Furthermore, the ultrasonic reaction unit is a continuous tubular reactor or a multi-stage series tank reactor; when it is a continuous tubular reactor, its length-to-diameter ratio is not less than 10:1.

[0037] Among them, tubular reactors with a specific aspect ratio are suitable for continuous processing, while trough reactors are suitable for staged processing. This ensures that solutions with different viscosity characteristics can obtain sufficient reaction intensity and residence time.

[0038] Furthermore, the precise drug dosing unit includes a pH adjuster storage tank, a purifier storage tank, a high-precision metering pump, and an online mixer, wherein the online mixer is located between the drug dosing point and the ultrasonic reaction unit.

[0039] In this way, the high-precision metering pump ensures the accuracy of the dosage, and the online mixer avoids local overconcentration of the reagent. The combination of the two is a prerequisite for reducing reagent consumption, reducing gallium loss, and achieving a stable reaction.

[0040] Furthermore, the online monitoring unit includes an online analyzer, an online pH meter, and a temperature sensor for monitoring the concentration of impurities in the gallium solution.

[0041] Among these, the impurity concentration, which directly reflects the purification effect, and the pH and temperature, which affect the reaction process, are the sensing guarantees for achieving adaptive optimization and closed-loop control.

[0042] Furthermore, the intelligent control unit includes: The data acquisition module is used to receive and store the monitoring data from the online monitoring unit; The purification model module includes a built-in ultrasound-pharmaceutical synergistic purification model based on mass transfer kinetics and energy consumption optimization. The parameter optimization module is used to calculate the optimal ultrasonic parameters and reagent dosage based on monitoring data, target water quality, and the purification model. The execution control module is used to send control commands to the ultrasonic reaction unit and the precise drug dosing unit.

[0043] Furthermore, a complete intelligent decision-making chain is formed, from data collection, model analysis, optimization calculation to instruction execution.

[0044] Furthermore, the purifying agent is one or more of a sulfiding agent, a complexing agent, and an adsorbent.

[0045] The system clarifies the range of chemical treatment agents it can be adapted to. Whether it is sulfide precipitation, complexation or adsorption, the system can be enhanced by ultrasound and combined with intelligent control to select the optimal solution for different impurities.

[0046] A method for deep purification of gallium, employing the aforementioned system for deep purification of gallium, and for purifying gallium-rich precipitates obtained in one of the objectives of this invention, includes the following steps: S0: Release the gallium-rich precipitate obtained above. The releasing agent is dilute sulfurous acid or a mixed solvent of dilute hydrochloric acid and sodium sulfite. Under the conditions of 40~60℃ and solid-liquid ratio of (3~8):1 L / kg, stir the reaction for 30~90 min. After filtration, the filtrate is a gallium-rich gallium solution to be treated.

[0047] S1: The gallium solution to be treated is transported to the ultrasonic reaction unit, and the influent water quality parameters are monitored in real time using the online monitoring unit; S2: The intelligent control unit automatically calculates the optimal ultrasonic parameters, reaction temperature, pH adjustment range, and purification agent dosage based on the influent water quality parameters and the preset purification model. S3: The precise dosing unit adds pH adjuster and purifier based on calculation results to adjust the pH of the solution; S4: Start the multi-frequency combined ultrasonic transducer array and carry out ultrasonic enhanced purification reaction under optimized ultrasonic parameters and reaction temperature; S5: After the reaction is complete, the solution is subjected to solid-liquid separation to obtain a purified gallium solution.

[0048] In step S0, the acidic environment effectively disrupts the complex structure between gallium and the temperature-sensitive leaching agent in the gallium-rich precipitate, allowing gallium ions to be released into the solution while the temperature-sensitive leaching agent is in an expanded state, forming a crude gallium solution. The selected sulfurous acid or introduced sulfite ions have reducing properties. During the dissolution process, it can pre-reduce vanadium impurities existing in the crude gallium solution in a high-valence state to a low-valence state, thus making the vanadium impurities easier to remove selectively in subsequent steps.

[0049] In step S4, the ultrasonic power density is controlled at 200-500 W / L, the reaction temperature at 30-60℃, and the reaction time at 20-60 min.

[0050] By employing a complete process flow from water inlet, monitoring, intelligent decision-making, reagent dosing, ultrasonic reaction to water effluent, and combining typical parameter windows for achieving deep purification goals, such as power density, temperature, and time, highly efficient gallium purification has been achieved.

[0051] Furthermore, the purified gallium solution obtained in step S5 has a vanadium impurity concentration of less than 1 ppm and a gallium loss rate of ≤0.5%.

[0052] The present invention has the following beneficial effects when applied: First, the broadband cavitation effect generated by multi-frequency combined ultrasound, in synergy with precisely added purifying agents, can efficiently destroy the existing forms of impurity ions and enhance their precipitation or adsorption reactions. Combined with pH control optimized for gallium solution characteristics, it can deeply remove key impurities such as vanadium while greatly suppressing gallium co-precipitation, keeping the gallium loss rate at an extremely low level, meeting the preparation requirements of 4N and above high-purity gallium.

[0053] Secondly, the localized high temperature and pressure and strong micro-jet generated by multi-frequency ultrasonic cavitation greatly enhance the mass transfer process and reduce the reaction activation energy. The turbulence-enhancing structure further optimizes the flow field and acoustic field within the reactor, eliminating dead zones. The synergy of these two factors significantly accelerates reaction kinetics, greatly reducing the processing time required by traditional purification processes.

[0054] Furthermore, the closed-loop control system, comprised of the online monitoring unit and the intelligent control unit, enables fully automated operation from influent monitoring, parameter optimization, process control to effluent feedback. This system can adjust parameters such as ultrasonic power, frequency, and reagent dosage in real time based on fluctuations in influent water quality, ensuring long-term stable compliance of effluent water quality, reducing reliance on manual experience, and improving the reliability and consistency of the process.

[0055] Furthermore, the four functional modules of ultrasonic enhancement, reagent dosing, online monitoring, and intelligent control are organically integrated into a collaborative system, overcoming the shortcomings of existing technologies such as single-function equipment and poor linkage. This design takes into account both continuous and batch / cascade processing requirements. It can flexibly select purifying agents and process parameters by calling or optimizing the purification model according to gallium solutions with different sources and impurities, demonstrating good versatility and adaptability.

[0056] Meanwhile, a specialized design was developed to address the industry-specific challenges of high density, high viscosity, and difficulty in impurity separation in gallium solutions. A combination of multi-frequency ultrasound and a turbulence-inducing structure ensured efficient energy transfer in high-viscosity media; and targeted selection of purifying agents and intelligent control effectively overcame the vanadium-gallium separation problem. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0058] In the first step of enriching gallium in gallium-vanadium precipitates, the gallium-vanadium precipitates are first subjected to a graded synergistic activation pretreatment.

[0059] Specifically, the process begins with chemical pre-activation, selectively reacting the interface of the gallium-encapsulated material to alter its chemical state without dissolving the material as a whole. Next, filler implantation is performed to implant sites capable of efficiently absorbing and converting ultrasonic energy into the surface cracks of the pre-etched material. Finally, coupled activation and structural restructuring are conducted to fix the material modification effects resulting from the chemical pre-activation and filler implantation, forming an activated precursor.

[0060] Furthermore, regarding chemical pre-activation, the following steps are performed: First, the gallium-vanadium precipitate, in this embodiment, can be preliminarily crushed or ground using ferric vanadate, calcium vanadate, or a saturated adsorbent, with the particle size controlled at 100-200 mesh to ensure sufficient contact with the reagent. Then, the raw material and water are mixed in a pretreatment reaction tank at a liquid-to-solid ratio of 5:1 to 8:1 (volume / mass ratio) to form a homogeneous slurry. This liquid-to-solid ratio ensures both good flowability and sufficiently effective reagent concentration.

[0061] Next, the reaction tank is slowly stirred at 50-100 rpm. The pH of the slurry is adjusted to a weakly acidic range of 3.5-5.5 using dilute acid (dilute sulfuric acid in this example) or dilute alkali (sodium hydroxide in this example). The pH window is then adjusted to create an environment that promotes the complexation reaction without causing large-scale dissolution of vanadium precipitates.

[0062] Finally, slowly add pre-prepared citric acid (0.2–0.8 mol / L) to the pH-adjusted slurry. Maintain slow, continuous stirring at a gentle temperature of 40–60°C to carry out the pre-activation reaction for 1.5–3 hours. Do not apply high-energy ultrasound or strong mechanical stirring during this stage to avoid damaging the fine structure formed during pre-activation.

[0063] Citric acid, in particular, has a strong complexing ability for iron and vanadium ions due to its carboxyl group. It can preferentially dissolve metal ions at the grain boundaries of precipitates such as iron vanadate, achieving grain boundary corrosion and exposing the encapsulated gallium. Its reducing properties can also reduce some V5+ to V4+, reducing the solubility of vanadium in subsequent acid leaching.

[0064] Regarding the aforementioned chemical pre-activation, at the microscopic level, it selectively dissolves grain boundaries, creating a micron / nanoscale crack network and pores within the originally dense vanadium precipitate particles. These channels become the preferred paths for subsequent ultrasonic cavitation microjets and shock wave propagation. Moreover, chemical pre-activation is a necessary means for subsequent ultrasonic-enhanced leaching. Without chemical pre-activation, the original vanadium precipitate (with intact crystals, dense structure, and high acoustic impedance) will have most of the energy generated by ultrasonic cavitation reflected or dissipated as heat on the particle surface, making it difficult to penetrate deep into the particle to destroy the lattice encapsulating gallium. Even if ultrasound accidentally causes damage to the particle surface, the newly exposed fracture surface has uniform chemical properties, and conventional leaching agents will indiscriminately attack the entire fracture surface, resulting in the simultaneous and massive dissolution of vanadium and gallium, making selective leaching impossible. Furthermore, without the diffusion channels created by pre-activation, the leaching agent and reaction products need to undergo extremely slow bulk diffusion through the dense solid, resulting in a very slow reaction rate.

[0065] Furthermore, regarding the implantation of filler material, the following steps are performed: First, receive the slurry that has undergone the aforementioned chemical pre-activation. At this stage, the slurry consists of solid particles and a solution that have undergone preliminary interfacial reactions. Fine-tune the slurry temperature to a level that is conducive to subsequent dispersion and adhesion, but not too high to avoid excessive microbubble rupture, such as 30-50°C, and maintain the pH in the range of 3.5-5.5. Maintain slow stirring at 80 rpm.

[0066] Next, a carboxylated nano-silica dispersion with a particle size of 20-100 nm, at a dry basis weight of 0.1% to 0.5%, is slowly added to the reaction tank. The stirring speed is immediately increased to 300-600 rpm and maintained for 10-15 minutes to ensure uniform dispersion of the nanoparticles in the slurry. Mechanical force and chemical action are then used to adhere the carboxylated nano-silica to the surface of the solid particles and into cracks.

[0067] Furthermore, nitrogen or air is bubbled into the bottom of the slurry in the form of bubbles with a target particle size of 10-100 micrometers, accounting for 0.5%-2% of the total slurry volume, using a microbubble generator. At the same time, 5-20 ppm of polylactic-co-glycolic acid copolymer (PLGA) is added to encapsulate the microbubbles, enhancing their stability in the slurry and preventing rapid coalescence and breakage.

[0068] The introduction of nano-silica allows stress concentration points to be pre-embedded on the surface of the vanadium precipitate. Steady-state microbubbles serve as pre-designed cavitation nuclei. When the main ultrasonic field is activated, the ultrasonic energy is preferentially absorbed by these pre-designed cavitation nuclei and converted into a violent cavitation effect. The resulting shock waves and microjets are then focused and amplified by the stress concentration points, thus achieving the most effective directional destruction of the encapsulated structure with minimal input energy.

[0069] Furthermore, regarding coupling activation and structural reorganization, the following steps are employed: Return the stirring speed of the aforementioned reaction slurry to 50-100 rpm and continue stirring at 70-80°C for 20-30 minutes. This promotes the strong adhesion of nanoparticles to the solid surface. It also ensures that stable microbubbles are uniformly distributed in the slurry, and that their hydrophobic shells bond with the surfaces of similarly hydrophobic material particles or cracks through hydrophobic interactions. This allows the system to reach a metastable state, forming a composite structure of solid particles / attached nanoparticles / adsorbed microbubbles. Finally, cool the slurry to the temperature required for adding the temperature-sensitive leaching agent, i.e., 20-30°C, to obtain the aforementioned activated precursor slurry.

[0070] Under gentle heating at 70-80℃ and continuous stirring, the molecular thermal motion of the system intensifies. The carboxyl groups on the surface of nano-silica and the hydroxyl groups on the material surface more readily undergo dehydration condensation to form more stable chemical bonds, or to form a stronger coordination / hydrogen bond network. This transforms the nanoparticles from physical adhesion to chemical anchoring, firmly fixing them to the pre-designed fragile interfaces and crack tips, becoming permanent stress concentration points that cannot be detached under subsequent ultrasonic treatment.

[0071] Moreover, the mild conditions of 70-80°C provide additional energy to the system. This facilitates atomic rearrangement of the unstable, high-surface-energy crack inner walls caused by chemical etching, resulting in a slightly relaxed structure and release of some stress at the crack tip. This, in turn, makes the crack more susceptible to propagation under subsequent mechanical forces rather than healing. Driven by thermal energy, the atomic diffusion capacity within the material is enhanced. Chemical pre-activation alters the chemical composition and bonding forces in the crack tip region, and thermal energy promotes slow, non-catastrophic crack propagation in these weakened areas, making the micron-scale crack network wider and more interconnected. This pre-loosens the cracks before ultrasonic treatment. Simultaneously, for the PLGA polymer shell, this temperature is close to its glass transition temperature, slightly softening the shell and allowing it to better conform to the solid surface contour, increasing adhesion strength. This ensures that microbubbles, acting as pre-set cavitation nuclei, remain stably present at the target location until ultrasonic treatment is initiated.

[0072] Therefore, after coupling activation, during subsequent ultrasonic treatment, the ultrasound waves first act on the pre-defined microbubbles, generating a violent and controllable cavitation effect at their adsorption sites. The energy of the cavitation shock wave and microjets is focused and amplified at the stress concentration point at the crack tip, driving the crack to propagate efficiently along a pre-weakened path. The expanded fresh surface immediately reacts with the leaching agent, rapidly dissolving.

[0073] When enriching gallium in gallium-vanadium precipitates, after completing the graded synergistic activation pretreatment of gallium-vanadium precipitates, the pretreated gallium is selectively leached using a temperature-sensitive leaching agent under ultrasonic conditions.

[0074] Specifically, the temperature of the activated precursor slurry is controlled at 20~30℃, a temperature-sensitive leaching agent is added, and the mixture is stirred evenly to obtain the leaching slurry.

[0075] The thermosensitive leaching agent is a copolymer with poly(N-isopropylacrylamide) as the thermosensitive segment and 8-hydroxyquinoline-5-sulfonic acid as a gallium chelating ligand linked by amide bonds. It is prepared using the following method: Purchase poly(N-isopropylacrylamide) with a carboxyl end group and a molecular weight of approximately 5000-10000 Da, as well as an amino-modified gallium-specific chelating ligand. In this example, 8-hydroxyquinoline-5-sulfonic acid is selected.

[0076] Poly(N-isopropylacrylamide) was dissolved in anhydrous dimethyl sulfoxide, and excess carbodiimide and N-hydroxysuccinimide were added. The mixture was stirred for 2-4 hours at room temperature under nitrogen protection to activate the terminal carboxyl groups and form an active ester, which was then used as the activation solution.

[0077] An anhydrous dimethyl sulfoxide solution of 8-hydroxyquinoline-5-sulfonic acid was slowly added dropwise to the above activation solution, with a small amount of triethylamine added as a catalyst. The amidation coupling reaction was carried out at 25°C, in the dark, under nitrogen protection for 12-24 hours.

[0078] After the reaction is complete, the mixture is added dropwise to a large amount of cold diethyl ether or n-hexane to precipitate. The precipitate is collected by centrifugation and washed several times with diethyl ether to remove unreacted small molecules. Finally, the product is dried under vacuum to obtain a temperature-sensitive leaching agent.

[0079] For the prepared temperature-sensitive leaching agent, at temperatures below the LCST, its poly(N-isopropylacrylamide) chains hydrophilically extend, resulting in good overall molecular solubility. The chelating ligand groups are fully exposed, allowing free diffusion and complexation with gallium ions in the solution to form a soluble complex. At temperatures above the LCST, its chains hydrophobically collapse and intermolecular aggregation occurs, leading to a sharp drop in the solubility of the entire molecular / metal complex, causing it to precipitate from the solution.

[0080] Specifically, this refers to the selective leaching of gallium from a leaching slurry under ultrasonic conditions.

[0081] The instantaneous collapse of an ultrasonic cavitation bubble generates a localized high temperature exceeding 5000K within a very small space. Although the overall solution temperature is controllable, the instantaneous high temperature generated by cavitation on the surface of solid particles, especially near microcracks generated after pretreatment and near stress concentration points, is sufficient to subject temperature-sensitive leaching agent molecules to an environment exceeding LCST locally, triggering conformational changes.

[0082] Specifically, during the leaching process, firstly, the pretreated activated precursor slurry is mixed with a temperature-sensitive leaching agent at an overall temperature below the LCST. At this time, the leaching agent is in an extended state, and its chelating ligand groups diffuse with the solution, selectively binding with exposed gallium ions through channels and cracks created by the pretreatment. Secondly, low-frequency high-intensity ultrasound is activated; in this embodiment, 20kHz~40kHz is selected. Cavitation generates further tearing cracks, exposing new gallium sites and creating instantaneous high-temperature hot spots at the particle / solution interface, causing the nearby temperature-sensitive leaching agent / gallium ion complex to rapidly contract and aggregate. This is equivalent to locking gallium in the hydrophobic polymer clusters formed on the surface of the solid particles the instant it is leached, immediately separating it from the bulk solution, thereby breaking the liquid-phase mass transfer equilibrium, driving the leaching reaction to continue to the right, and greatly inhibiting the co-dissolution of vanadium.

[0083] In the ultrasonic process, low-frequency ultrasonic cavitation bubbles (20-40 kHz) are large, have high collapse energy, and generate strong macroscopic jets and shock waves. For pretreated materials, their main function is to promote macroscopic crack propagation. Along the microcracks generated during pretreatment, they utilize implanted nano-silica as stress concentration points to tear and expand the cracks, achieving physical opening of inclusions. However, if used alone or at excessively high intensity, it may lead to over-pulverization of the material, creating fresh, non-selective interfaces, which is detrimental to selectivity. High-frequency ultrasonic cavitation bubbles (80-120 kHz) are small and dense, with gentler collapse, but generate stronger micro-turbulence and chemical free radicals. For pretreated materials, their main function is to selectively chemically attack and clean the interfaces within the opened microcracks and on the modified interfaces. High-frequency ultrasound can promote the diffusion of temperature-sensitive leaching agents within the pores, accelerating their complexation reaction with exposed gallium, while continuously flushing the reaction interface with micro-jet streams to prevent passivation. High-frequency ultrasound causes minimal damage to the overall structure, avoiding ineffective vanadium dissolution.

[0084] Therefore, the pretreated material structure is weakened, and extremely high power densities are not required. Excessive power, such as >500 W / L, will cause the activated precursor to be violently crushed, disrupting the preset chemical gradient and leading to a decrease in selectivity.

[0085] Therefore, in this embodiment, a combination of a 20-40 kHz low-frequency main frequency and an 80-120 kHz high-frequency auxiliary frequency is used. The low frequency is responsible for periodic, short-pulse crack propagation, while the high frequency is responsible for continuous or long-pulse interfacial reactions and mass transfer. Intermittent pulsed ultrasound is employed. During the active phase, the temperature-sensitive leaching agent chelates the target gallium ions; during the intermittent phase, the reactants diffuse to the interface. This prevents localized overheating from causing overall deactivation of the temperature-sensitive leaching agent or undesirable side reactions.

[0086] Finally, after the reaction is complete, sonication is stopped, and the overall temperature is raised to above LCST, i.e., 35-45°C. All the temperature-sensitive leaching agent / gallium ion complex is precipitated. Simple filtration and solid-liquid separation yield a gallium-rich precipitate and a leaching tail solution almost devoid of gallium. Redispersing the precipitate with cold water allows the complex to dissociate, releasing a high-concentration gallium solution. The temperature-sensitive leaching agent returns to its extended state and can be recycled.

[0087] The following detailed description uses actual embodiments. Example

[0088] The method described in the foregoing embodiments shall be adopted.

[0089] The slurry was adjusted to pH 4.0 with dilute sulfuric acid, and 0.5 mol / L citric acid was added. The mixture was reacted at 50°C for 2 hours. 0.3% carboxylated nano-silica was added and dispersed for 15 minutes, followed by the introduction of nitrogen microbubbles coated with 1% PLGA. The mixture was then maintained at 75°C with slow stirring for 25 minutes, and cooled to 25°C to obtain the activated precursor.

[0090] Add 1.8 times the molar amount of gallium-sensitive leaching agent, namely poly(N-isopropylacrylamide) / 8-hydroxyquinoline-5-sulfonic acid.

[0091] The dual-frequency combination pulse ultrasound of 28kHz and 100kHz was turned on, working for 3 seconds with a 2-second interval, with a total power density of 400 W / L. The reaction was carried out at 25℃ for 40 minutes, during which 2 g / L sodium sulfite was added as an auxiliary agent.

[0092] After the reaction is complete, rapidly heat to 40°C, let stand for 10 minutes, and then filter.

[0093] In this embodiment, the gallium leaching rate is >98%, and the vanadium co-dissolution rate is <2%. Example

[0094] Based on Example 1, the ultrasound conditions were changed. In this example, the ultrasound was performed at a single frequency of 28kHz, continuously, with a total power density of 400 W / L. The rest was the same as in Example 1. Example

[0095] Based on Example 1, the ultrasonic conditions were changed. In this example, the ultrasound was performed at a single frequency of 100kHz, continuously, with a total power density of 400 W / L. The rest was the same as in Example 1. Example

[0096] Based on Example 1, the ultrasound conditions are changed. In this example, the ultrasound uses a dual-frequency combination of 28kHz and 100kHz and operates continuously. The rest is the same as in Example 1.

[0097] Comparing Examples 1 to 4, Example 2 showed poor selective leaching of gallium, with a large amount of vanadium co-leaching; Example 3 showed good selectivity but a low leaching rate; Example 4 was better than Examples 2 and 3, but had higher energy consumption and temperature rise, and ultimately the enrichment effect of gallium was worse than that of Example 1. Therefore, the dual-frequency pulse mode of Example 1 achieved the best results in terms of efficiency and selectivity.

[0098] Comparative Example 1 In this comparative example, conventional ultrasonic leaching without pretreatment was used.

[0099] Specifically, the raw materials were directly pulped, the pH was adjusted to 2 with sulfuric acid, and an equivalent amount of sulfuric acid as in Example 1 was added as a leaching agent. The mixture was reacted at 60°C for 120 minutes under the same total power density of 400 W / L and single-frequency continuous ultrasound at 28 kHz. The mixture was then filtered.

[0100] In this comparative example, the gallium leaching rate was low, less than 45%, while the vanadium co-dissolution rate was high, greater than 20%, resulting in poor selectivity. Without pretreatment to break up the encapsulation and the use of ultrasonic energy guidance from the filler, conventional methods using conventional leaching agents are inefficient.

[0101] Comparative Example 2 In this comparative example, the same pretreatment as in Example 1 was used, but conventional leaching agents and single-frequency ultrasound were used for treatment.

[0102] Specifically, the pretreatment was performed exactly the same as in Example 1 to obtain the activated precursor. However, the leaching agent was changed to 1.5 mol / L sulfuric acid, and the ultrasonic conditions were the same as in Comparative Example 1, i.e., 28 kHz single frequency, 400 W / L, 60°C, and reaction in a reactor for 120 min. Filtering followed.

[0103] Compared to Comparative Example 1, the gallium leaching rate has improved to 70%, but the vanadium co-dissolution rate is still relatively high, greater than 15%, and requires high temperature and long time.

[0104] Therefore, pretreatment alone cannot solve the problem of chemical selectivity; sensitive leachants and optimized ultrasound are indispensable for achieving high selectivity.

[0105] Comparative Example 3 In this comparative example, a scheme with pretreatment and temperature-sensitive leaching agent was used, but without ultrasound or only mechanical stirring.

[0106] Specifically, the same pretreatment as in Example 1 was performed, with the same sensitive leaching agent added, but without turning on the ultrasound. Instead, mechanical stirring was carried out at 300 rpm at 25°C for 40 or 120 minutes, followed by heating to 40°C for sedimentation and filtration.

[0107] In this comparative example, the gallium leaching rate was extremely low, less than 30%, and the reaction was extremely slow. Therefore, the cavitation and microjets generated by ultrasound are the key driving forces for disrupting the microstructure after pretreatment and realizing efficient mass transfer and reaction of the smart leaching agent in the microchannel.

[0108] Comparative Example 4 In this comparative example, a scheme with pretreatment and optimized ultrasound was adopted, but a conventional non-thermosensitive leachate was used.

[0109] Specifically, the same pretreatment and ultrasonic conditions as in Example 1 were performed. However, the leaching agent was replaced with an equimolar amount of the conventional high-efficiency gallium complexing agent ethylenediaminetetraacetic acid (EDTA). After the reaction, the mixture was directly filtered at 25°C.

[0110] In this comparative example, the gallium leaching rate was relatively high, reaching 85%, but the vanadium co-dissolution rate was significantly increased, exceeding 15%, and the resulting solution after filtration was a mixed solution containing gallium, vanadium, and EDTA, making separation and purification complex. Therefore, the temperature-sensitive leaching agent not only provides selectivity, but its temperature-induced precipitation characteristics also enable in-situ primary separation of the products, simplifying the process.

[0111] In summary, Comparative Example 1 showed poor results. Furthermore, Comparative Examples 2, 3, and 4, which simply combined pretreatment, a temperature-sensitive leachate, and multi-frequency ultrasound, or Examples 2, 3, and 4 with suboptimal parameters, all failed to achieve the optimal synergistic effect of high efficiency, high selectivity, and short process demonstrated in Example 1 of this application.

[0112] Pretreatment creates an interface and channel for subsequent steps; the temperature-sensitive leachate utilizes this interface to achieve chemically selective recognition and product separation; multi-frequency pulsed ultrasound serves as the physical environment, driving the former two to complete the reaction efficiently.

[0113] After obtaining the gallium-rich precipitate obtained in Example 1 above, it is subjected to deep purification. Specifically, a system for deep purification of gallium includes the following main units: The ultrasonic reaction unit is a closed or open corrosion-resistant reaction chamber (material can be 316L stainless steel lined with PTFE or titanium), which contains a multi-frequency combined ultrasonic transducer array and a turbulence enhancement structure. The transducer array includes at least one set of main frequency transducers and at least one set of auxiliary frequency transducers. The frequency range of the main frequency transducers is 20~40Hz, and the frequency range of the auxiliary frequency transducers is 60~100kHz. The frequency ratio of the main frequency to the auxiliary frequency is 1.5:1 to 4:1, and the power ratio of the main frequency to the auxiliary frequency is 60-80% for the main frequency and 20-40% for the auxiliary frequency.

[0114] The ultrasonic reaction unit can be a continuous tubular reactor or a multi-stage series tank reactor. When it is a continuous tubular reactor, its length-to-diameter ratio is ≥10:1, and it is equipped with multiple sets of ultrasonic transducers arranged alternately along the axial direction to ensure that the solution is subjected to uniform ultrasonic action during flow. When it is a multi-stage series tank reactor, different ultrasonic parameters can be set for each stage of the reactor to achieve graded gradient treatment.

[0115] The turbulence-enhancing structure consists of a spiral guide plate or a wave-shaped reflector plate installed on the inner wall of the reaction unit. This guide plate helps the solution form a spiral flow path, extending the effective residence time, while simultaneously reflecting and scattering ultrasonic waves to enhance the uniformity of the cavitation field. A broadband cavitation effect is achieved through multi-frequency combination.

[0116] The precise dosing unit, connected to the ultrasonic reaction unit, includes a pH adjuster storage tank, a purifying agent storage tank, and a high-precision metering pump (metering accuracy ≤ ±1%) for quantitative dosing of the pH adjuster and purifying agent. It also includes an online mixer, located between the dosing point and the ultrasonic reaction unit, to premix the agent with the gallium solution and prevent excessively high local concentrations. The pH adjuster can be dilute sulfuric acid, hydrochloric acid, or sodium hydroxide solution; the purifying agent can be one or more of the following: a sulfiding agent (such as sodium sulfide or ammonium sulfide), a complexing agent (such as 8-hydroxyquinoline or ethylenediaminetetraacetic acid), or an adsorbent (such as a titanium-based adsorbent or modified bentonite), selected according to the type and properties of the target impurity.

[0117] An online monitoring unit, located at the inlet and / or outlet of the ultrasonic response unit, includes: Online vanadium / impurity analyzer: It can use inductively coupled plasma optical emission spectroscopy (ICP-OES) or electrochemical sensors to monitor the concentration of vanadium and other key impurities in the solution in real time; Online pH meter: Real-time monitoring of solution pH value, with an accuracy of ±0.1; Temperature sensor: Real-time monitoring of reaction temperature, with an accuracy of ±0.5℃; An optional turbidimeter or particle counter can be used to monitor the formation of precipitates during the reaction process in real time, indirectly reflecting the reaction progress.

[0118] The intelligent control unit, serving as the control center in this embodiment, is electrically connected to the ultrasonic reaction unit, the precise drug dosing unit, and the online monitoring unit. It receives online monitoring data and automatically optimizes ultrasonic parameters and drug dosage based on a preset purification model. Specifically, it includes: The data acquisition module is used to receive and store real-time data from the online monitoring unit, including influent water quality, effluent water quality, pH, temperature, etc. The purification model module has a built-in ultrasonic / chemical synergistic purification model based on mass transfer kinetics and energy consumption optimization. This model comprehensively considers the effects of ultrasonic parameters (power, frequency, time), chemical dosage, pH, temperature and other factors on impurity removal rate and gallium loss rate. The parameter optimization module automatically calculates the optimal ultrasonic parameters and reagent dosage based on the real-time influent water quality and the target effluent water quality, such as vanadium ≤1 ppm, using the purification model. The execution control module sends control commands such as frequency, power, and time to the ultrasonic reaction unit, and sends metering pump flow control commands to the precise drug dosing unit; The human-machine interface, using a touch screen or industrial computer, is used to display operating status, historical data, alarm information, and allows manual setting or modification of operating parameters; The data communication module supports data communication with the central control room or cloud platform, enabling remote monitoring and data analysis.

[0119] Auxiliary units, including feed pumps, discharge pumps, temperature control modules, such as jacketed heat exchangers, level gauges, flow meters, pressure gauges and other conventional auxiliary equipment, ensure stable system operation.

[0120] Furthermore, the system provided in this embodiment includes the following steps for deep purification of gallium-rich precipitates: S0: Release the gallium-rich precipitate obtained above. The releasing agent is dilute sulfurous acid or a mixed solvent of dilute hydrochloric acid and sodium sulfite. Under the conditions of 40~60℃ and solid-liquid ratio of (3~8):1 L / kg, stir the reaction for 30~90 min. After filtration, the filtrate is a gallium-rich gallium solution to be treated.

[0121] S1: The gallium solution to be treated is transported to the ultrasonic reaction unit, and the influent water quality parameters are monitored in real time using the online monitoring unit; S2: The intelligent control unit automatically calculates the optimal ultrasonic parameters, reaction temperature, pH adjustment range, and purification agent dosage based on the influent water quality parameters and the preset purification model. S3: The precise dosing unit adds pH adjuster and purifier based on calculation results to adjust the pH of the solution; S4: Start the multi-frequency combined ultrasonic transducer array and carry out ultrasonic enhanced purification reaction under optimized ultrasonic parameters and reaction temperature; S5: After the reaction is complete, the solution is subjected to solid-liquid separation to obtain a purified gallium solution.

[0122] Specifically, in the feeding and online monitoring process, the gallium solution to be purified (the gallium solution to be treated obtained through SO) is fed into the ultrasonic reaction unit via a feed pump. The online monitoring unit monitors the concentration of impurities (especially vanadium concentration), pH, and temperature in the influent in real time and sends the data to the intelligent control unit.

[0123] Intelligent parameter optimization: The intelligent control unit automatically calculates the optimal pH adjustment range, purifier dosage, ultrasonic parameters (power density, main frequency, auxiliary frequency, reaction time), and reaction temperature based on a preset purification model and real-time influent water quality. The target effluent water quality is set at a concentration of key impurities such as vanadium below 1 ppm and a gallium loss rate ≤0.5%.

[0124] Precise reagent dosing and pH adjustment are achieved through a smart control unit sending control commands to the precise reagent dosing unit. A high-precision metering pump then adds pH adjuster to the solution according to calculated values, adjusting the pH to (e.g., 2.0~4.0 is suitable for sulfide precipitation, 7.0~9.0 is suitable for adsorption purification). Simultaneously, a purifying agent is added, automatically adjusting based on impurity concentration. The reagent, pre-mixed with the gallium solution in an online mixer, then enters the ultrasonic reaction unit.

[0125] The ultrasonic-enhanced reaction involves an intelligent control unit sending control commands to the ultrasonic reaction unit to activate the multi-frequency combined ultrasonic transducer array. The ultrasonic power density is controlled at 200–500 W / L, the main frequency at 20–40 kHz, and the auxiliary frequency at 60–100 kHz. The reaction temperature is adjusted to 30–60 °C via a jacketed heat exchanger, and the reaction time (or residence time) is 20–60 min. In the broadband cavitation effect generated by the multi-frequency combined ultrasound, the main frequency (lower frequency) ultrasound produces strong but widely distributed cavitation bubbles, dominating macroscopic mass transfer and particle dispersion; the auxiliary frequency (higher frequency) ultrasound produces more but smaller cavitation bubbles, which can penetrate micropores and interfaces, dominating microscopic interface activation and surface cleaning. The synergistic effect of both greatly enhances the reaction rate and precipitation / adsorption efficiency between the purifying agent and impurity ions.

[0126] After solid-liquid separation, the reacted slurry is discharged through the discharge unit and sent to a solid-liquid separation device (such as a plate and frame filter press, centrifuge, or membrane separation unit) for separation. A deeply purified gallium solution is obtained, with the concentration of key impurities such as vanadium below 1 ppm. The separated impurity-enriched phase (the precipitate or adsorbent loaded with impurities) can be further processed to recover valuable metals, or partially reused after regeneration.

[0127] The feedback regulation involves an online monitoring unit that monitors the effluent water quality in real time. When the concentration of impurities in the effluent approaches a set threshold, the intelligent control unit automatically adjusts the ultrasonic parameters or the dosage of reagents to maintain stable compliance. For example, when the vanadium concentration in the effluent rises to 0.8 ppm, the system automatically increases the ultrasonic power density by 10% or extends the reaction time by 5% to ensure that the effluent concentration remains below 1 ppm.

[0128] In this embodiment, when purifying gallium using the aforementioned system, the combination of the main frequency and auxiliary frequency forms a broadband cavitation field in the solution, covering mass transfer interfaces of different sizes and precipitated particles of different diameters, significantly improving the utilization efficiency of cavitation energy. The local high temperature generated by the cavitation effect can reach 5000 K, the high pressure can reach 1000 atm, and the strong micro-jets greatly enhance the mass transfer process between the purifying agent and impurity ions, and reduce the reaction activation energy.

[0129] Moreover, the turbulence-enhancing structure guides the solution to form a complex flow path, continuously delivering the solution to the high-energy ultrasonic region, while reflecting and scattering ultrasonic waves, eliminating processing dead zones, and ensuring that every part of the solution is subjected to uniform ultrasonic action.

[0130] Considering the high density and viscosity of gallium solutions, this embodiment employs multi-stage series reactors or tubular reactors with optimized aspect ratios to ensure sufficient residence time and processing intensity. Simultaneously, precise control of pH and the type of purifying agent minimizes gallium co-precipitation losses.

[0131] The following detailed implementation method will provide a further explanation. Example

[0132] The gallium-rich precipitate obtained in Example 1 was used, and the gallium solution obtained in step S0 was adjusted to pH 2.5.

[0133] System Configuration: The system employs the deep gallium purification system described in the preceding embodiments. The ultrasonic reaction unit is a continuous tubular reactor with an effective volume of 100 L and an aspect ratio of 12:1. It internally incorporates a multi-frequency ultrasonic transducer array: the main frequency transducer group has a frequency of 28 kHz and a power of 6 kW; the auxiliary frequency transducer group has a frequency of 80 kHz and a power of 2 kW. An internal spiral guide plate serves as a turbulence-enhancing structure. The reagent precision dosing unit is equipped with sodium sulfide and dilute sulfuric acid storage tanks, and the metering pump accuracy is ±0.5%. The online monitoring unit is equipped with an online ICP-OES and an online pH meter. The intelligent control unit uses a PLC control system with a built-in purification model.

[0134] Operating parameters: Feed flow rate: 200 L / h, residence time: 30 min; The intelligent control unit calculates and optimizes the parameters: target effluent V ≤ 0.8 ppm; pH adjustment: Add dilute sulfuric acid to adjust the pH to 3; Purifying agent: Sodium sulfide, dosage 0.6 g / L; Ultrasonic parameters: power density 400W / L (total power 8 kW / 100 L), main frequency 28kHz (power percentage 75%), auxiliary frequency 80kHz (power percentage 25%), reaction temperature 45℃.

[0135] In this embodiment, after 72 hours of continuous operation, the effluent was analyzed by ICP-MS, and the average concentrations of V, Fe, Cu, and Zn were 0.62 ppm, 0.4 ppm, 0.3 ppm, and 0.2 ppm, all below 1 ppm. The gallium loss rate, calculated by material balance, was 0.4%. The unit energy consumption was 1.2 kWh / m³.

[0136] Comparative Example 5 The same feed and reagents as in Example 5 were used, but the ultrasonic reaction unit was replaced with a conventional single-frequency ultrasonic device (fixed frequency 28 kHz, no turbulence structure, no intelligent control), and the other parameters were the same (power density 400 W / L, residence time 30 min).

[0137] In this comparative example, after 30 minutes of ultrasonic reaction, the effluent V concentration was 8.5 ppm, which did not reach the target of 1 ppm. Extending the residence time to 60 minutes reduced the effluent V concentration to 3.2 ppm, but it was still above 1 ppm. The gallium loss rate was 1.1%. Example

[0138] Using the system configuration of Example 1, the actual production solution of a gallium smelter was processed. The concentration of V in the influent fluctuated in the range of 10-40 ppm and ran continuously for 7 days.

[0139] Operating mode: The adaptive optimization function of the intelligent control unit is enabled. The preset target effluent V concentration is ≤0.8 ppm, and the gallium loss rate is ≤0.5%. The intelligent control unit automatically optimizes the pH, purifier dosage, and ultrasonic parameters based on the online monitoring of the influent water quality.

[0140] Execution result:

[0141] In this embodiment, the effluent V concentration remained consistently below 0.8 ppm throughout all time periods, and the gallium loss rate was ≤0.5%. The average unit energy consumption was 0.95 kWh / m3, which is approximately 35% lower than that of operation with fixed parameters (always using high power mode to cope with high concentrations). Example

[0142] Using the system configuration of Example 5, the same gallium solution was treated, and the purification effects of different purifying agents were compared.

[0143]

[0144] In this embodiment, the combination of sodium sulfide and 8-hydroxyquinoline as the combined purifying agents has a synergistic removal effect on multiple impurities, resulting in the optimal overall effluent quality. Example

[0145] The treatment effect with and without the spiral guide plate was compared, and other parameters were the same as in Example 5.

[0146] Among them, without a spiral guide plate, the effluent V concentration is 1.2ppm, and the acoustic field test inside the reactor shows that there are obvious dead zones.

[0147] With the spiral guide plate, the effluent concentration V is 0.62 ppm, and the uniformity of the sound field is significantly improved.

[0148] Therefore, the turbulence-enhancing structure improves the uniformity of the cavitation field and significantly enhances the treatment effect.

[0149] In summary, the ultrasonic enhanced reaction system for deep purification of gallium solution provided by this invention integrates a multi-frequency combined ultrasonic reaction unit, a reagent precision dosing unit, an online monitoring unit, and an intelligent control unit, achieving efficient deep removal of key impurities such as vanadium from gallium solution. The effluent impurity concentration is consistently below 1 ppm, with low gallium loss rate, low operating energy consumption, and a high degree of automation.

[0150] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for efficient enrichment from gallium-vanadium precipitates, characterized in that, Includes the following steps: Gallium-vanadium precipitate was mixed with water to prepare a slurry, which was then subjected to chemical preactivation, filler implantation and coupling activation in sequence to obtain an activated precursor slurry. The temperature of the activated precursor slurry is controlled at 20~30℃, a temperature-sensitive leaching agent is added, and the mixture is mixed evenly to obtain a leaching slurry; the temperature-sensitive leaching agent is a copolymer with poly(N-isopropylacrylamide) as the temperature-sensitive segment and 8-hydroxyquinoline-5-sulfonic acid as the gallium chelating ligand connected by amide bonds. The ultrasonic reaction is initiated on the leachate slurry, and the ultrasonic field is controlled in a dual-frequency combination mode with a main frequency of 20~40kHz and an auxiliary frequency of 80~120kHz. The power ratio of the main frequency to the auxiliary frequency is 60~80%: 20~40%, the total power density is 300~500 W / L, the overall reaction temperature is maintained at 20~30℃, and the reaction time is 20~60 minutes. After the reaction is complete, the entire reaction system is heated to 35-45°C, and after standing, solid-liquid separation is performed to obtain gallium-rich precipitate and leaching tail liquid. The gallium-rich precipitate is mixed with a releasing agent to obtain a released gallium-rich crude solution.

2. The method for efficient enrichment from gallium-vanadium precipitates according to claim 1, characterized in that, The chemical preactivation includes: Control the liquid-to-solid ratio of the slurry to 5-8 L / kg, adjust the pH to 3.5-5.5 with dilute sulfuric acid, add citric acid with a concentration of 0.2-0.8 mol / L, and react for 1.5-3 hours under stirring conditions of 40-60℃ and 50-100 rpm. The filler implantation includes: In the chemically pre-activated slurry, add carboxylated nano-silica with a particle size of 20-100 nm at 0.1%-0.5% by dry basis material mass, and disperse at 30-600 rpm for 10-15 minutes; Nitrogen microbubbles encapsulated in PLGA, comprising 0.5% to 2% of the total volume of the slurry, are bubbled into the slurry. The microbubbles have a particle size of 10 to 100 μm. The coupling activation includes: The slurry after the filler is implanted is maintained at 70~80℃ and 50~100 rpm for 20~30 minutes, and then cooled to the temperature required for adding the temperature-sensitive leaching agent to obtain the activated precursor slurry.

3. The method for efficient enrichment from gallium-vanadium precipitates according to claim 1, characterized in that, The temperature-sensitive leaching agent is prepared by the following steps: dissolving carboxyl-terminated poly(N-isopropylacrylamide) in anhydrous dimethyl sulfoxide, activating its terminal carboxyl group in the presence of carbodiimide and N-hydroxysuccinimide, and then performing an amidation coupling reaction with an amino derivative of 8-hydroxyquinoline-5-sulfonic acid. The reaction product is obtained after precipitation, washing, and drying. The amount of the temperature-sensitive leaching agent added, based on the molar amount of the 8-hydroxyquinoline-5-sulfonic acid group in its structure, is 1.5 to 3.0 times the theoretical molar amount of gallium in the slurry.

4. The method for efficient enrichment from gallium-vanadium precipitates according to claim 1, characterized in that, The ultrasonic field adopts a pulse working mode with a pulse working cycle of 2-5 seconds and an interval of 1-3 seconds. During the ultrasonic action, sodium sulfite is added to the slurry at a dosage of 1-5 g / L.

5. The method for efficient enrichment from gallium-vanadium precipitates according to claim 1, characterized in that, During the heating process after the ultrasonic reaction, the reaction system is heated to 35-45°C within 2-5 minutes, and then allowed to stand at this temperature for 5-15 minutes before solid-liquid separation.

6. A system for deep purification of gallium, characterized in that, For purifying gallium-rich precipitates obtained from the method for efficient enrichment from gallium-vanadium precipitates according to any one of claims 1 to 5, comprising: An ultrasonic reaction unit includes a reaction cavity and a multi-frequency combined ultrasonic transducer array and a turbulence enhancement structure disposed within the reaction cavity. A precise drug dosing unit is connected to the ultrasonic reaction unit and is used to add pH adjuster and purifier to the ultrasonic reaction unit; An online monitoring unit is used to monitor the parameters of the gallium solution at the inlet and / or outlet of the ultrasonic reaction unit in real time; The intelligent control unit is electrically connected to the ultrasonic reaction unit, the precise drug dosing unit, and the online monitoring unit. It is used to optimize and control the ultrasonic parameters of the ultrasonic reaction unit and the drug dosing amount of the precise drug dosing unit based on the monitoring data of the online monitoring unit and the preset purification model.

7. A system for deep purification of gallium according to claim 6, characterized in that, The multi-frequency combined ultrasonic transducer array includes at least one set of main frequency transducers and at least one set of auxiliary frequency transducers. The frequency range of the main frequency transducers is 20~40 kHz, and the frequency range of the auxiliary frequency transducers is 60~100 kHz. The power ratio of the main frequency to the auxiliary frequency is 60~80% for the main frequency and 20~40% for the auxiliary frequency. The turbulence enhancement structure is a spiral guide plate or a wave-shaped reflector plate disposed on the inner wall of the reaction chamber. The ultrasonic reaction unit is a continuous tubular reactor or a multi-stage series tank reactor; when it is a continuous tubular reactor, its length-to-diameter ratio is not less than 10:

1.

8. The system for deep purification of gallium according to claim 1, characterized in that, The precise dosing unit for the reagent includes a pH adjuster storage tank, a purifier storage tank, a high-precision metering pump, and an online mixer. The online mixer is located between the reagent dosing point and the ultrasonic reaction unit. The online monitoring unit includes an online analyzer, an online pH meter, and a temperature sensor for monitoring the concentration of impurities in the gallium solution; The purifying agent is one or more of the following: sulfiding agent, complexing agent, and adsorbent.

9. The system for deep purification of gallium according to claim 1, characterized in that, The intelligent control unit includes: The data acquisition module is used to receive and store the monitoring data from the online monitoring unit; The purification model module includes a built-in ultrasonic / pharmaceutical synergistic purification model based on mass transfer kinetics and energy consumption optimization. The parameter optimization module is used to calculate the optimal ultrasonic parameters and reagent dosage based on monitoring data, target water quality, and the purification model. The execution control module is used to send control commands to the ultrasonic reaction unit and the precise drug dosing unit.

10. A method for deep purification of gallium, characterized in that, For the gallium-rich precipitate obtained from the method for efficient enrichment from gallium-vanadium precipitates according to any one of claims 1 to 5, purification is performed using the system for deep gallium purification according to any one of claims 6 to 9, comprising the following steps: S0: Release the gallium-rich precipitate obtained by any one of claims 1 to 5, wherein the releasing agent is dilute sulfurous acid or a mixed solvent of dilute hydrochloric acid and sodium sulfite, and the reaction is carried out at 40 to 60°C with a solid-liquid ratio of (3 to 8): 1 L / kg for 30 to 90 min by stirring. The filtrate after filtration is a gallium-rich gallium solution to be treated. 11.S1. The gallium solution to be treated is transported to the ultrasonic reaction unit, and the influent water quality parameters are monitored in real time using the online monitoring unit; S2. The intelligent control unit automatically calculates the optimal ultrasonic parameters, reaction temperature, pH adjustment range, and purification agent dosage based on the influent water quality parameters and the preset purification model. S3. The precise dosing unit adds pH adjuster and purifier based on calculation results to adjust the pH of the solution; S4. Start the multi-frequency combined ultrasonic transducer array and carry out ultrasonic enhanced purification reaction under optimized ultrasonic parameters and reaction temperature; S5. After the reaction is complete, the solution is subjected to solid-liquid separation to obtain a purified gallium solution; in, In step S4, the ultrasonic power density is controlled at 200~500 W / L, the reaction temperature is 30-60℃, and the reaction time is 20~60 min.

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