Preparation method of efficient separation adsorbent for indium and germanium in zinc solution

Abstract

The invention relates to the technical field of adsorbent preparation, and discloses a preparation method of an efficient separation adsorbent for indium and germanium in a zinc solution, which comprises the following steps: in a porous inorganic mineral substrate, dipping a mixed solution containing an organic functional agent, a monomer, a cross-linking agent, a pore-foaming agent and an organic solvent under ultrasonic treatment; the in-situ polymerization reaction and the polymerization-induced phase separation process are carried out concurrently through cooperative regulation and control of multiple chemical and physical processes, physical embedding of the functional agent on the mineral substrate is achieved to solve the loss problem, and meanwhile the in-situ polymerization reaction and the polymerization-induced phase separation process are carried out at the same time. And an internal microporous structure of a polymer network is synchronously constructed, and the chemical activity of the functional agent is guaranteed, so that the adsorbent has high stability and high-speed mass transfer kinetics.

Description

Technical Field

[0001] This invention relates to a method for preparing an indium-germanium high-efficiency separation adsorbent in zinc solution, belonging to the field of adsorbent preparation technology. Background Technology

[0002] In hydrometallurgical industries, recovering trace amounts of valuable metals indium and germanium from high-zinc, strong-acid leachates is one of the core technological challenges in this field. Using inexpensive natural mineral materials such as bentonite or diatomaceous earth as carriers, highly selective organic functional agents, such as organophosphate extractants, are loaded using chemical or physical methods to prepare composite adsorbents. However, these conventional preparation methods face inherent fundamental flaws in continuous industrial operation, namely the physical loss of organic functional agents. The binding between functional agent molecules and the inorganic substrate relies mainly on weak physical adsorption forces. Under continuous scouring of high-acidity, high-ionic-strength solutions, the functional agents inevitably desorb and detach from the substrate, leading to a rapid decline in adsorbent performance and causing secondary pollution to subsequent processes.

[0003] In the industry, some methods involve adding complexing agents and using ion exchange resins with specific functions to adsorb germanium and avoid physical loss. For example, Chinese invention patent CN117089728B discloses a method for efficient adsorption and recovery of germanium, which uses tartaric acid as a complexing agent and macroporous strong basic anion exchange resin to recover germanium-tartaric acid complexes. This method introduces an additional complexing agent (tartaric acid) into the process, which not only increases material costs, but also makes process control, such as the molar ratio of the complexing agent to germanium and pH value, relatively complex. More importantly, this approach relies on high-cost functional polymer resins, rather than the technical route based on inexpensive natural mineral substrates that this invention focuses on.

[0004] Therefore, the technical problem to be solved by this invention is how to provide a preparation method that can stably fix the functional agent on the mineral substrate by in-situ polymerization, and also control the internal microporous structure of the polymer network formed at the process level to ensure mass transfer kinetics. Summary of the Invention

[0005] This invention provides a method for preparing an indium-germanium high-efficiency separation adsorbent in zinc solution. Its main purpose is to solve the problem of how to achieve stable fixation of functional agents on mineral substrates through in-situ polymerization, while synergistically regulating the internal microporous structure of the polymer network and effectively managing the micro-reaction heat of the polymerization process.

[0006] To achieve the above objectives, the present invention provides a method for preparing an indium-germanium high-efficiency separation adsorbent in zinc solution, comprising the following steps:

[0007] Step 101: Provide a porous or layered inorganic mineral substrate;

[0008] Step 102: Immerse the inorganic mineral substrate in a mixed solution, the mixed solution comprising: an organic functional agent having selective complexing ability for indium or germanium, a polymerizable matrix monomer, a polymerizable crosslinking agent, a thermal polymerization initiator, a pore-forming agent, and an organic solvent, wherein the boiling point of the organic solvent matches the polymerization initiation temperature of the thermal polymerization initiator.

[0009] Step 103: During the impregnation process, ultrasonic treatment is applied to the suspension system consisting of the inorganic mineral substrate and the mixed solution.

[0010] Step 104: Under the condition that the organic solvent boils and forms reflux, the impregnated inorganic mineral substrate is heated to trigger the thermal polymerization initiator, so that the matrix monomer and crosslinking agent undergo in-situ polymerization reaction in the pores or interlayer domains of the inorganic mineral substrate, and the polymerization-induced phase separation process is induced by the pore-forming agent; the reflux absorbs the heat of reaction released by the in-situ polymerization reaction.

[0011] Step 105: Wash and dry to obtain the adsorbent; wherein the organic functional agent is formed by in-situ polymerization reaction, and the polymer network with microporous structure is physically embedded in the pores or interlayer domains;

[0012] Furthermore, the inorganic mineral matrix is ​​bentonite or diatomaceous earth; the organic functional agent is di(2-ethylhexyl)phosphoric acid; the matrix monomer is styrene; the crosslinking agent is divinylbenzene; and the pore-forming agent is a poor solvent selected from long-chain fatty alcohols and saturated alkanes.

[0013] Preferably, the pore-forming agent is a poor solvent; in step 104, the polymerization-induced phase separation process includes: as the matrix monomer is converted into a polymer network, the solubility of the polymer network in the poor solvent decreases and phase separation occurs, forming a polymer-rich solid framework and a liquid micro-region rich in poor solvent; the washing in step 105 is also used to remove the poor solvent and the liquid micro-region.

[0014] Preferably, in step 103, the frequency of the ultrasonic treatment is 20kHz to 40kHz, and the power density of the ultrasonic treatment is 10W / L to 100W / L.

[0015] Preferably, the heating in step 104 is carried out in a reactor equipped with a reflux condenser, and an external heating temperature is set that is higher than the boiling point of the organic solvent in order to maintain the boiling and reflux of the organic solvent.

[0016] Preferably, the method further includes a step of acid activation treatment of the inorganic mineral substrate between step 101 and step 102; the acid activation treatment is performed in a 1 mol / L to 2 mol / L sulfuric acid solution at 80°C. Up to 90 The next two hours will be spent.

[0017] Preferably, the method further includes step 601, collecting the acidic washing solution generated by the acid activation treatment, the acidic washing solution containing metal ions dissolved from the inorganic mineral substrate, and the method further includes step 602, prior to step 102, using the acidic washing solution or its treatment product to perform surface modification on the acid-activated inorganic mineral substrate, forming adsorption sites for metal ions on the surface of the pores or interlayer domains of the inorganic mineral substrate.

[0018] Preferably, the method further includes, prior to step 102, pre-fixing the thermal polymerization initiator onto the surface of the pores or interlayer domains of the inorganic mineral substrate by chemical bonding, wherein the mixed solution in step 102 does not contain the thermal polymerization initiator, and the in-situ polymerization reaction in step 104 is triggered by the thermal polymerization initiator fixed on the surface of the inorganic mineral substrate.

[0019] Preferably, the method further includes, prior to step 103, step 901, determining the effective pore volume of the inorganic mineral substrate from step 101. ; and in step 103, the total amount of the mixed solution applied for impregnation It is based on the effective pore volume The total amount applied is dynamically determined. With effective pore volume The following relationship must be satisfied: ,in For control coefficients, control coefficients The value range is from 0.90 to 0.98.

[0020] Preferably, the inorganic mineral substrate is bentonite or diatomaceous earth, and the metal ions dissolved from the inorganic mineral substrate include aluminum ions or iron ions. Step 602, surface modification, includes: adjusting the pH value of the acidic washing solution to the range of 2.5 to 4.0, so that aluminum ions or iron ions are adsorbed on the surface of the inorganic mineral substrate in the form of polynuclear hydroxy complexes.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. By introducing a specific porogen into the mixed solution, the polymerization reaction and phase separation process can proceed concurrently when the in-situ polymerization step takes place within the pores of the inorganic mineral substrate. This synergistic mechanism of chemical and physical methods ensures that while the polymer network is forming and physically encapsulating the organic functional agent, a continuous microporous structure is also being constructed within the network. This avoids the technical bias of polymer densification and blockage of active sites caused by conventional bulk polymerization, enabling the final adsorbent to achieve high kinetic characteristics of ion diffusion while possessing the stability of functional agent fixation.

[0023] 2. The method of the present invention limits the impregnation step to be carried out under ultrasonic treatment. It utilizes the microscopic physical effect generated by ultrasonic cavitation on the surface of inorganic mineral substrate particles to transform passive capillary diffusion into active forced infusion. This physical method enhances mass transfer, avoids viscosity and interfacial energy barriers in the mixture of organic functional agents and monomers, and ensures homogeneous and deep penetration of functional components in the micropores and interlayer domains of the substrate. This provides process assurance for subsequent in-situ polymerization to occur in an ideal micro-region environment and avoids loss of substrate outer surface and internal capacity due to uneven impregnation.

[0024] 3. The method of the present invention synergistically limits the physical properties of the organic solvent used in the chemical process steps, such as its boiling point, and the reaction conditions of the chemical process steps, such as reflux. It utilizes the latent heat of phase change of the solvent as an in-situ heat dissipation mechanism within the micropores of the inorganic mineral substrate. When the polymerization reaction is exothermic, the excess heat is instantly absorbed and discharged by the boiling and vaporization process of the solvent, so that the actual reaction temperature inside the pores is passively and constantly clamped at the boiling point of the solvent, avoiding local thermal runaway caused by poor thermal conductivity of the mineral substrate, and protecting the chemical structural stability and activity of the organic functional agent during the polymerization process. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the process flow and synergistic mechanism of the preparation method of the present invention;

[0026] Figure 2 This is a comparison diagram showing the effect of ultrasonic-enhanced impregnation on the uniformity of functional agent distribution according to the present invention.

[0027] Figure 3 This is a schematic diagram of the preparation system and its material flow according to the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments described herein are only used to explain this invention and are not intended to limit the scope of protection of this invention.

[0029] This invention provides a method for preparing an indium-germanium high-efficiency separation adsorbent in zinc solution, including substrate provision and pretreatment, enhanced impregnation of a functional mixed solution, and a thermally controlled reaction stage involving polymerization and phase separation. Through the synergistic use of multiple physicochemical methods, it solves the technical problems of easy loss of functional agents, poor mass transfer kinetics, and easy degradation of functional agents during the preparation process in traditional supported adsorbents. The initial step of this method is to provide a porous or layered inorganic mineral substrate, which serves as the carrier and reaction space for subsequent in-situ polymerization. In the field of adsorbent material preparation, bentonite or diatomaceous earth are preferred substrate materials due to their pore or interlayer structure, high specific surface area, and cost-effectiveness. To remove pore impurities, activate the surface, and increase the interlayer spacing or pore volume to facilitate the full penetration of subsequent functional components, it is preferable to perform an acid activation treatment on the inorganic mineral substrate before the impregnation step. A specific, non-limiting acid activation treatment procedure is: placing the substrate material in a 1 mol / L to 2 mol / L sulfuric acid solution at 80°C. Up to 90 The mixture was stirred for 2 hours under controlled temperature conditions, then washed until neutral and dried for later use; a mixed solution containing multifunctional components was prepared, which serves as the material basis for constructing the functional core of the adsorbent; the mixed solution contains: a para-indium ion or germanium ions ( The polymer network consists of: an organic functional agent with selective complexing ability, such as di(2-ethylhexyl)phosphoric acid (also known as P204), which selectively captures target metal ions through specific chemical groups; a polymerizable matrix monomer and a polymerizable crosslinking agent, such as styrene and divinylbenzene, which are the structural units forming the polymer network framework; a thermal polymerization initiator, such as azobisisobutyronitrile, used to trigger the polymerization reaction at a specific temperature; a porogen, which induces phase separation during polymerization to construct the internal microporous structure of the polymer network; and an organic solvent, used to dissolve all the above components to form a homogeneous system. The porogen is preferably a poor solvent for the formed polymer network, such as one selected from long-chain fatty alcohols and saturated alkanes. This poor solvent is miscible with the monomer before polymerization. After polymerization begins, as the polymer chain grows, the thermodynamic equilibrium of the system is broken, and the polymer solubility rapidly decreases, thereby inducing a polymerization-induced phase separation process, forming a polymer-rich solid framework and a liquid-phase microregion rich in the poor solvent, laying the foundation for the subsequent formation of interconnected mass transfer channels. This indicates divalent zinc ions. This represents trivalent indium ions. This indicates a tetravalent germanium ion.

[0030] In conventional impregnation processes, high-viscosity mixtures of organic functional agents and monomers inevitably suffer from capillary resistance, hindering uniform penetration into the deep micropores or narrow interlayer regions of inorganic mineral substrates. To address this mass transfer issue, ultrasonic treatment is applied to the suspension system composed of the inorganic mineral substrate and the mixed solution during impregnation. The ultrasonic cavitation effect generates microjets and localized high shear forces near the substrate particle surface, transforming capillary diffusion into forced infusion. This ensures that all components, including the organic functional agents, can homogeneously and deeply fill the pores or interlayer regions of the substrate, guaranteeing subsequent in-situ polymerization in an ideal micro-region environment. This process achieves effective cavitation in the treatment of such mineral substrate materials. To ensure effective infusion and avoid excessive ultrasonic energy input that could lead to localized polymerization, the ultrasonic treatment frequency can be set between 20kHz and 40kHz, and the power density between 10W / L and 100W / L. This parameter range is based on a technical trade-off: ensuring the microjets are sufficient to overcome the viscous resistance and interfacial energy barrier of the mixed solution. Frequency below 20kHz or power density below 10W / L may result in inhomogeneous infusion. It is also necessary to prevent energy concentration that could cause localized overheating of the solvent or premature decomposition of the initiator; this risk exists when the frequency is above 40kHz or the power density is above 100W / L. A crucial step after impregnation is when the organic solvent boils and refluxes. Under these conditions, an inorganic mineral substrate is heated. This process design aims to synergistically address the challenge of thermal runaway in in-situ free radical polymerization, a highly exothermic reaction that easily occurs within the micropores of such poorly conductive mineral substrates. Thermal runaway leads to localized temperature increases, causing thermal decomposition or chemical denaturation of temperature-sensitive organic functional agents, resulting in loss of complexing activity. To achieve this, the boiling point of the organic solvent used in the mixed solution is selected to match the polymerization initiation temperature of the thermal polymerization initiator. The heating step can be carried out in a reactor equipped with a reflux condenser, with an external heating temperature set above the boiling point of the organic solvent. Under these conditions, the system is heated to the boiling point of the organic solvent, causing the solvent to begin boiling and forming a stable reflux. The initiator of thermal polymerization triggers an in-situ polymerization reaction between the matrix monomers and crosslinking agents within the pores or interlayer regions of the substrate. Any excess heat released by the polymerization reaction is instantly absorbed by the solvent within the pores and discharged to the reflux condenser through the solvent's vaporization process, i.e., the latent heat of phase change. This mechanism utilizes the latent heat of phase change of the solvent as an in-situ adaptive heat dissipation mechanism to stably control the actual reaction temperature inside the pores at the boiling point of the solvent, thereby effectively avoiding local thermal runaway and protecting the chemical activity of the organic functional agents. Simultaneously with this in-situ polymerization reaction, a polymerization-induced phase separation process induced by the porogen, i.e., the poor solvent, occurs concurrently, ultimately forming a polymer network with a microporous structure within the pores.

[0031] After the polymerization reaction is complete, the product is washed and dried. This washing step serves a dual function: first, it removes residual unreacted monomers, initiators, and unencapsulated functional agents; second, it thoroughly removes the liquid-phase micro-regions rich in pore-forming agents (poor solvents) formed during the polymerization-induced phase separation process. After these liquid-phase micro-regions are eluted, the space they occupy remains, forming a microporous structure that permeates the interior of the polymer network. The resulting adsorbent has its organic functional agents physically encapsulated within the pores or interlayer domains of the microporous polymer network formed by the in-situ polymerization reaction. This structure addresses the loss of functional agents under high-acid, high-ionic-strength solutions through physical encapsulation, while simultaneously ensuring that target metal ions, such as indium and germanium, can rapidly diffuse and contact the internal active sites through the synchronously constructed internal microporous structure, giving the adsorbent both high stability and high-speed mass transfer kinetics. This process does not depart from the core concept of the invention. Under these circumstances, those skilled in the art can make various improvements to the above method. In a preferred embodiment, to further enhance the bonding strength between the polymer network and the pore walls of the inorganic substrate, and to make the polymerization reaction more controllably initiated from the substrate surface, the thermal polymerization initiator can be pre-fixed on the surface of the pores or interlayer domains of the inorganic mineral substrate through chemical bonding. The mixed solution used for impregnation does not contain free thermal polymerization initiator. The in-situ polymerization reaction in the subsequent heating step is triggered by the thermal polymerization initiator fixed on the substrate surface. This interface-initiated mode helps to form a polymer network that is more firmly anchored to the substrate and has a more uniform structure. To address the reality that the porosity of natural mineral substrates, such as bentonite and diatomaceous earth, may fluctuate between different batches, a process control method based on material characteristic feedforward control is introduced. Specifically, before the impregnation step, it may also include: measuring the effective pore volume of the provided inorganic mineral substrate. The maximum liquid absorption of the substrate can be determined using conventional methods in the art, such as titration with the maximum adsorption capacity of a solvent (e.g., n-heptane) or centrifugal retention; the total amount of the mixed solution applied during the impregnation step... It is no longer a fixed value, but is based on the effective pore volume. Dynamic determination, making and Satisfying the relation: ,in, To control the coefficient, the preferred value range is 0.90 to 0.98. This approach, by slightly under-filling the total volume of the mixed solution, utilizes capillary force to preferentially fill the pores, ensuring that all functional components are absorbed into the internal pores of the substrate while the outer surface of the substrate remains relatively dry. This eliminates the problem of functional agent polymerization on the outer surface of the substrate caused by excessive impregnation, thereby improving the effective encapsulation rate of functional agents and the batch stability of the product. In a preferred embodiment of the acid activation step, to further utilize the components dissolved from the substrate itself to enhance interfacial bonding, the acidic washing solution generated by the acid activation treatment is collected. This acidic washing solution contains metal ions, mainly aluminum ions, dissolved from inorganic mineral substrates such as bentonite or diatomaceous earth. or iron ions Before the impregnation step, an additional step is added: surface modification of the acid-activated inorganic mineral substrate is performed using the collected acidic washing solution or its treatment product; specifically, the modification method involves adjusting the pH of the acidic washing solution to a range of 2.5 to 4.0, under which conditions aluminum ions... or iron ions The metal ion is re-adsorbed and immobilized on the surface of the pores or interlayer domains of the inorganic mineral substrate in the form of polynuclear hydroxyl complexes, forming adsorption sites with Lewis acidity. These in-situ constructed metal ion adsorption sites can then interact with organic functional agents in the mixed solution, such as the P=O groups of P204, or monomers such as styrene, during subsequent impregnation and polymerization steps. - Electron clouds, through acid-base complexation or coordination, act as chemical anchors, enhancing the interfacial bonding strength between the subsequently formed polymer network and the pore walls of the inorganic substrate. This prevents the polymer-functional agent complex from undergoing overall delamination under harsh operating conditions. This indicates trivalent aluminum ions. This indicates ferric ions. , It is a positive integer. and These represent the number of positive charges carried by the polynuclear hydroxyl complexes of aluminum and iron, respectively.

[0032] Example 1: In conventional modification methods for porous mineral substrates such as bentonite or diatomaceous earth, the in-situ polymerization to form a polymer network within the pores to immobilize organic functional agents faces two main technical limitations: First, the polymerization process tends to form a dense polymer solid, which, while encapsulating the functional agent, also forms a mass transfer barrier, resulting in low adsorption kinetics; second, the strong exothermic nature of in-situ free radical polymerization, within the confined space of the poorly conductive micropores of the mineral substrate, easily leads to localized thermal runaway due to the inability to instantly dissipate heat, resulting in the degradation of organic functional agents, such as di(2-ethylhexyl)phosphoric acid. The polymer loses its selective complexing ability due to thermal decomposition. By introducing a specific porogen into the mixed solution, the in-situ polymerization reaction and the polymerization-induced phase separation process occur concurrently during the heating stage in step 104. This mechanism allows the polymer network to simultaneously form and physically encapsulate the organic functional agent while simultaneously constructing a permeable microporous structure within the network. This overcomes the kinetic limitations of polymer densification and blockage of active sites caused by conventional bulk polymerization. Simultaneously, it limits the boiling point of the organic solvent in the mixed solution to match the polymerization initiation temperature of the thermal polymerization initiator, limiting the heating step 104 to the point where the organic solvent boils and forms a pore. The process is carried out under reflux conditions. This step utilizes the latent heat of phase change of the organic solvent as a heat dissipation pathway. When the polymerization reaction is exothermic, the excess heat is instantly absorbed and discharged during the boiling and vaporization process of the solvent, stabilizing the actual reaction temperature inside the pores at the solvent boiling point. This protects the chemical structural stability and activity of the organic functional agent during the polymerization process. The realization of the polymerization-induced phase separation mechanism and the reflux heat control mechanism depends on the ultrasonic treatment applied during the impregnation process in step 103. The physical effect of ultrasonic cavitation on the surface of the substrate particles ensures the presence of organic functional agents, monomers, initiators, pore-forming agents, and organic solvents. All liquid phase components, including those in the substrate, are homogeneous and deeply penetrated within the micropores and interlayer domains of the substrate, avoiding viscosity and interfacial energy barriers. This mass transfer step provides the material basis for the subsequent polymerization-induced phase separation to occur uniformly throughout the entire substrate, ensuring that the organic solvent can exert its temperature control effect of latent heat of phase change in each reaction micro-region. This preparation method, through the synergy of physical mass transfer, phase separation pore-forming, and process heat control, transforms the in-situ polymerization process, which is prone to kinetic failure or activity degradation in conventional methods, into a controllable preparation process. The final adsorbent product achieves stable immobilization of functional agents in its structure.

[0033] Example 2: This example uses a set of control experiments to verify the synergistic effect of key process steps in the preparation method of the present invention, namely ultrasonic treatment, introduction of pore-forming agent, and reflux heat control, on the preparation of adsorbents that combine functional agent stability and high adsorption kinetics; Experimental materials and standard preparation procedures (sample group of the present invention): Inorganic mineral substrate: 100-mesh sodium-based bentonite was selected, treated according to the acid activation method, and in 1.5 mol / L sulfuric acid solution at 85°C. Stir for 2 hours, wash until neutral, and then at 105 Dry for 6 hours before use; Preparation of mixed solution (per 100g dried substrate): Weigh 30g of organic functional agent di(2-ethylhexyl)phosphoric acid, 20g of matrix monomer styrene, 3g of crosslinking agent divinylbenzene (55% purity), 0.5g of thermal polymerization initiator azobisisobutyronitrile, 40g of pore-forming agent dodecanol, and 100mL of organic solvent cyclohexane; Mix and dissolve the above components to form a homogeneous mixed solution; the boiling point of organic solvent cyclohexane is approximately 81°C. The polymerization initiation temperature is matched to that of the initiator azobisisobutyronitrile (AIBN); Step 103 (Impregnation): 100g of dry, acid-activated bentonite substrate is added to the above mixed solution to form a suspension system. The suspension system is placed in an ultrasonic cleaner and treated for 60 minutes at a frequency of 30kHz and a power density of 50W / L to ensure that the mixed solution fully penetrates; Step 104 (Polymerization): The impregnated substrate is transferred to a reactor equipped with a reflux condenser and a nitrogen protection device. The external heating bath is set to a temperature of 85°C. This causes the cyclohexane solvent in the reactor to boil and maintain a stable reflux state (reactor temperature approximately 81°C). Under these conditions, the reaction proceeds for 5 hours; Step 105 (post-processing): After the reaction is complete, the mixture is cooled to room temperature, and the product is washed with anhydrous ethanol in a Soxhlet extractor for 12 hours to remove unreacted monomers, porogens, and residual functional agents on the surface. Finally, the product is processed at 80°C. Vacuum drying for 8 hours yields the sample of this invention.

[0034] Preparation of control groups: To verify the necessity of specific process steps, four control groups were prepared. Except for the following key deviations, the materials and parameters were consistent with the standard preparation procedure of the present invention: Control group A (simulating traditional physical impregnation): Only washing and drying in steps 1 and 105 were performed; the substrate was impregnated in a solution containing only 30g of di(2-ethylhexyl)phosphoric acid and 100mL of cyclohexane (no monomer, initiator, or porogen), stirred for 60 minutes as usual, and then directly washed and dried with ethanol; Control group B (without porogen): The preparation procedure was consistent with the present invention, except that 40g of dodecanol, the porogen, was not added in the mixed solution preparation in step 2; Control group C (without reflux heat control): The preparation procedure was consistent with the present invention, except that a reflux condenser was not used in the polymerization stage of step 4, and the impregnated substrate was placed in a nitrogen-filled forced-air oven at 81°C. Heating at a constant temperature for 5 hours; Control group D (no ultrasonic treatment): The preparation procedure is the same as that of the sample group of this invention. In the impregnation stage of step 3, no ultrasonic treatment is applied, and conventional mechanical stirring (150 rpm) is used for 60 minutes.

[0035] Performance testing procedure: Functional agent loss rate test (stability): Accurately weigh 0.5g of each sample adsorbent and place it in 50mL of pH 1.5 sulfuric acid solution and maintain the temperature at 25°C. Shake at 150 rpm for 24 hours; take the supernatant and analyze the total organic carbon (TOC) content of the supernatant. Calculate the loss of functional agent based on the carbon content of di(2-ethylhexyl)phosphoric acid, with results expressed as mg / g P2O4 / g adsorbent; Adsorption kinetics and capacity test (effectiveness): Prepare a simulated high-zinc acidic leachate with the following composition: Zn²⁺ 120 g / L, In³⁺ 150 mg / L, Ge 4 ⁺ 50 mg / L, pH adjusted to 1.5 with sulfuric acid; accurately weigh 0.5 g of each sample group of adsorbent and place it in 50 mL of the above simulated solution, shake at 25℃ and 150 rpm; take samples at 30 minutes and 240 minutes (equilibrium time) respectively, determine the remaining concentration of In³⁺ in the solution, calculate the indium adsorption rate (%) and equilibrium adsorption capacity (mg / g) at 30 minutes, and test results and analysis: the performance test data of each sample group are summarized in Table 1.

[0036] Table 1: Comparison of Stability and Adsorption Performance of Adsorbents in Each Sample Group

[0037]

[0038] Data analysis is as follows: Data from control group A (traditional impregnation) shows a high P204 loss rate of 18.5 mg / g, indicating instability in industrial applications, despite its high initial adsorption kinetics and capacity. Control group B (without porogen) shows an extremely low P204 loss rate (0.4 mg / g) compared to the sample group of this invention, indicating that in-situ polymerization effectively solves the loss problem; however, its 30-minute adsorption rate (15.3%) and equilibrium capacity (4.8 mg / g) are both extremely low. This data objectively confirms that in the absence of a porogen to induce phase separation, The dense polymer network formed severely hinders ion mass transfer, preventing contact between active sites. Compared with the sample group of this invention, control group C (without reflux heat control) also showed a very low P2O4 loss rate (0.6 mg / g), and its equilibrium adsorption capacity (3.1 mg / g) was even lower than that of control group B. This data objectively confirms that without a reflux heat control mechanism (i.e., utilizing the latent heat of solvent phase change), the strong exothermic polymerization within the micropores of the mineral substrate leads to local overheating, causing the organic functional agent P2O4 to undergo chemical degradation and lose its complexing activity. Control group D (without ultrasonic treatment) and Compared with the sample group of this invention, the loss rate (4.7 mg / g) was much higher than that of the sample group of this invention (0.5 mg / g), and the equilibrium capacity (9.2 mg / g) was also reduced. This data objectively confirms that conventional stirring cannot achieve homogeneous and deep impregnation, resulting in a large amount of functional agents and monomers being enriched only on the outer surface of the substrate. This part is not effectively embedded in the pores after polymerization and is easily lost, resulting in insufficient embedding rate of the internal effective pores. The data of the sample group of this invention shows that its P2O4 loss rate (0.5 mg / g) is at an extremely low level, similar to groups B and C, indicating that the functional... The adsorbent is stable and immobilized; its 30-minute adsorption rate (93.8%) and equilibrium adsorption capacity (12.4 mg / g) are comparable to those of control group A (unpolymerized) and are much higher than those of groups B, C, and D. This data confirms that the preparation method disclosed in this invention, through the synergistic effect of three key process steps—ultrasonic treatment, pore-forming agent-induced phase separation, and reflux heat control—solves the problem of functional agent loss while constructing open microporous mass transfer channels, protecting the chemical activity of functional agents, and enabling the adsorbent to simultaneously achieve high levels of stability, kinetics, and capacity.

[0039] Example 3: This example combines Figures 1 to 3 The preparation method of an indium-germanium high-efficiency separation adsorbent in zinc solution is described, as follows: Figure 1As shown, this method begins with providing a porous inorganic mineral substrate, such as bentonite or diatomaceous earth. An optional pretreatment step is step 101: substrate acid activation treatment, aimed at removing impurities, activating the surface, and increasing pore volume. The substrate then proceeds to step 103: ultrasonic-enhanced impregnation, where a mixed solution containing functional agents, monomers, crosslinking agents, initiators, pore-forming agents, and solvents is used for forced infusion to ensure homogeneous deep penetration. The core step is step 104: in-situ polymerization and phase separation. This step involves heating under reflux conditions with an organic solvent. Two synergistic mechanisms exist in this step: synergistic mechanism A: reflux thermal control, which uses the latent heat of phase change to prevent local overheating and protect the activity of the functional agents; and synergistic mechanism B: polymerization-induced phase separation, which uses the pore-forming agent to induce the simultaneous construction of microporous mass transfer channels. After the reaction is complete, step 105: washing and drying is performed to remove the pore-forming agent and unreacted substances and solidify the microporous structure, ultimately yielding an adsorbent product that combines high stability with high-speed mass transfer kinetics.

[0040] like Figure 2 As shown in the figure, the vertical axis of the graph represents the coefficient of variation (CV) of the functional agent distribution, and the horizontal axis represents the substrate depth (μm). The graph shows that the solid line representing ultrasonic treatment at 30kHz exhibits a rapidly decreasing CV value with increasing substrate depth, remaining at a low level. The dashed line representing conventional stirring and impregnation shows a CV value that remains at a high level throughout the entire substrate depth range. Figure 3 As shown, the system includes a raw material silo for providing an inorganic mineral substrate and functional mixed solution components. The substrate can first enter an optional acid activation treatment unit for pretreatment, producing an activated substrate and a collectable / reusable waste liquid for acid washing. Simultaneously, the mixed solution components are mixed in proportion in a mixed solution preparation tank. The activated substrate and the mixed solution enter an ultrasonic impregnation unit for enhanced mass transfer, producing an impregnated substrate. The impregnated substrate is sent to an in-situ polymerization reactor to perform the core preparation steps. The reactor is equipped with a nitrogen supply for inert atmosphere protection, a heating system for external heating, and condensate circulating water for reflux heat control. The polymerization product produced by the reactor enters a Soxhlet extraction washing unit to remove pore-forming agents and residues, producing a washing product and a collectable / reusable waste liquid for washing solvent. After the washing product is dried by a vacuum drying unit to remove the solvent, the finished adsorbent is obtained.

[0041] Example 4: This example provides another specific implementation of the preparation method of the present invention, the main difference being the selection of the porogen. In this example, the preparation procedure is basically the same as that of the sample group of the present invention in Example 2. In the preparation of the mixed solution in step 2, the original 40g of porogen dodecyl alcohol is replaced with an equal mass of porogen n-heptane, which is a poor solvent of saturated alkanes. All other materials, including the substrate, functional agent, monomer, crosslinking agent, initiator, solvent, dosage, and all process parameters of steps 1, 3, 4, and 5, are consistent with those of the sample group of the present invention in Example 2. The performance test of the obtained adsorbent showed that its P2O4 loss rate, 30-minute indium adsorption rate, and equilibrium adsorption capacity were at the same level as the test data of the sample group of the present invention in Example 2, indicating that using saturated alkanes as porogens can also construct effective microporous mass transfer channels through the polymerization-induced phase separation mechanism, and obtain an adsorbent product with both high stability and high activity.

[0042] Example 5: This example provides a method for determining the effective pore volume of an inorganic mineral matrix. The specific procedures, and based on these, demonstrate the execution of [the procedure]. Dynamically determine the total amount of mixed solution applied The preparation steps were designed to address the issues of mismatched impregnation amounts and loss of functional components due to polymerization on the outer surface of the substrate caused by batch fluctuations in the substrate. The effective pore volume of the substrate was also determined. This procedure employs a solvent adsorption-centrifugation retention method; take 10.0 g and centrifuge at 105 °C. 100-mesh sodium-based bentonite, dried to constant weight and untreated, was used as reference sample 1. It was completely immersed in 100 mL of n-heptane (a non-polar solvent that does not swell bentonite), sealed, and allowed to stand for 24 hours to allow for full penetration. The suspension was transferred to a centrifuge tube and centrifuged at a relative centrifugal force of 3000 G for 30 minutes to remove excess solvent between particles. After discarding the supernatant, the mass of the wet substrate was accurately weighed. The effective pore volume of reference sample 1 was calculated by dividing the mass increase (minus the dry weight of the substrate) by the density of n-heptane (0.684 g / mL). The concentration was 0.31 mL / g; acid activation treatment was performed and the activated solution was standardized. Take 100-mesh sodium-based bentonite from the same batch and process it according to the procedure in Example 2 (1.5 mol / L sulfuric acid, 85... The substrate was acid-activated (2 hours), washed, and dried to constant weight; the solvent adsorption-centrifugation retention procedure described above was repeated to determine the effective pore volume of the acid-activated substrate (reference sample 2). ; measured It is 0.45 mL / g.

[0043] based on Dynamically determine the total amount of mixed solution applied Taking the preparation of 100g of dried acid-activated substrate as an example, the total effective pore volume of the batch is: ; Set control coefficients as described in the specific implementation method ,Should The value is preferably in the range of 0.90 to 0.98 to ensure near-saturated pore filling and avoid excessive liquid wetting of the substrate's outer surface; the required total amount of mixed solution to be applied is calculated accordingly. : in, Apply the total amount to the mixed solution. For control coefficients, This represents the total effective pore volume of the substrate in this batch; substitute the values: ,according to Prepare and impregnate; according to the mass ratio of each component (organic functional agent, matrix monomer, crosslinking agent, thermal polymerization initiator, pore-forming agent, organic solvent) listed in Example 2, recalculate and prepare a homogeneous mixed solution with a total volume of exactly 42.75 mL; place 100 g of the acid-activated substrate, i.e., reference sample 2, in a container, add all of the 42.75 mL mixed solution, and use this pore-filling or initial wet impregnation method to ensure complete absorption of the solution by the substrate; perform the same steps as in Example 2: ultrasonic treatment (103), reflux polymerization (104), and washing and drying (105) to obtain the final adsorbent; this procedure ensures that the mixed solution is confined within... Within the defined pores, subsequent in-situ polymerization reactions are confined to the pores or interlayer domains of the substrate, avoiding subsequent loss caused by the polymerization of functional components on the outer surface of the substrate due to excessive impregnation.

[0044] Example 6: This example further specifies a procedure for surface modification of an inorganic mineral substrate using byproducts of the acid activation step. It addresses the potential problem of insufficient bonding strength and easy overall delamination under operating conditions caused by differences in interfacial properties between the polymer network and the pore walls of the inorganic substrate. When performing step 1 as described in Example 2, acid activation treatment of 100g of sodium-based bentonite is performed, and the filtered acidic washing solution is collected. ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy) analysis of this washing solution reveals that its main metal ion concentration is: Al³⁺. + 1850 mg / L, Fe³ + 420 mg / L; This is rich in Al³ + / Fe³ +The acidic washing solution is used as the raw material for subsequent modification steps. Before performing the impregnation step, 100g of bentonite substrate, after acid activation, washing, and drying, is subjected to surface modification in step 602. The substrate is redispersed in 500mL of deionized water, and the collected acidic washing solution is slowly added dropwise while stirring. The pH value of the suspension is monitored using an online pH meter, and dilute ammonia is added simultaneously to control and maintain the pH value of the system within the range of 3.5±0.2. Under these pH conditions, Al³ + With Fe³ + Ions undergo controlled hydrolysis to form or Polynuclear hydroxyl complexes were collected; this suspension was stirred at pH 3.5 for 2 hours, allowing these positively charged polynuclear hydroxyl complexes to deposit and fix on the surface of the negatively charged bentonite pores and interlayer domains through electrostatic adsorption and surface complexation, thus constructing in-situ adsorption sites for metal ions with Lewis acidity; the substrate modified in step 602 was filtered, washed to neutral, and dried, and then the adsorbent was prepared according to the subsequent steps of Example 2 or Example 4, including the preparation of mixed solution, ultrasonic impregnation, reflux polymerization, washing and drying; in the impregnation step, the organic functional agent (P=O group of P204) in the mixed solution and the monomer (styrene) The electron cloud will undergo acid-base complexation with the Al / Fe hydroxyl complex adsorption sites pre-fixed on the pore wall surface, causing subsequent in-situ polymerization to anchor on the pore surface and enhancing the interfacial bonding strength between the formed polymer network and the inorganic substrate pore wall.

[0045] Example 7: This example further specifies a particular process for pre-fixing a thermal polymerization initiator onto the surface of an inorganic mineral substrate. This addresses the problem that when the initiator is free in the mixed solution, the polymerization reaction may randomly initiate within the pores, potentially leading to weak bonding or uneven structure between the polymer network and the substrate pore walls. The initial steps of this example, namely step 101 and the acid activation treatment, are the same as in Example 2, resulting in a dry, acid-activated bentonite substrate. Before performing the impregnation step, an initiator chemical bonding step is added: 100g of dry, acid-activated bentonite is dispersed in 500mL of toluene, 10mL of 3-aminopropyltriethoxysilane is added, and the mixture is heated to 110°C under nitrogen protection. The reaction was refluxed for 24 hours, allowing 3-aminopropyltriethoxysilane to be grafted onto the hydroxyl groups on the bentonite surface via siloxane bonds, forming an amino-functionalized substrate. This substrate was then filtered, washed, and dried. Next, the amino-functionalized substrate was dispersed in 500 mL of dichloromethane, and 15 g of 4,4'-azobis(4-cyanopentyl chloride), an initiator molecule with acyl chloride groups at both ends, was added. The reaction was stirred at room temperature under nitrogen protection for 24 hours, allowing the acyl chloride groups to react with the amino groups on the substrate surface to form amide bonds, thus chemically bonding the azo initiator. The initiator is pre-fixed onto the surface of the pores or interlayer of an inorganic mineral substrate; the product is thoroughly washed to remove unreacted initiator and dried for later use; in subsequent steps, when preparing the mixed solution, the composition of the mixed solution is the same as in Example 2, except that it no longer contains 0.5 g of free thermal polymerization initiator azobisisobutyronitrile; in step 103 (ultrasonic impregnation), the substrate with the pre-fixed initiator is impregnated in this initiator-free mixed solution; in step 104 (reflux polymerization), the system is heated to the boiling point of cyclohexane (approximately 81°C). When the azo initiator fixed on the substrate surface is heated, it decomposes to generate active free radicals, triggering an in-situ polymerization reaction. Since the chain growth of the polymerization reaction extends from the surface of the substrate pore wall to the center of the pore, the resulting polymer network is anchored to the substrate surface by chemical bonds. At the same time, the polymerization process is more controlled and the network structure is more uniform.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an adsorbent for high-efficiency separation of indium and germanium in a zinc solution, characterized in that, The method comprises the following steps: Step 101, providing a porous or layered inorganic mineral substrate; Step 102, immersing the inorganic mineral substrate in a mixed solution, the mixed solution comprising: an organic functional agent having selective complexing ability for indium or germanium, a polymerizable base monomer, a polymerizable crosslinking agent, a thermal polymerization initiator, a porogen, and an organic solvent, wherein the boiling point of the organic solvent matches the polymerization initiation temperature of the thermal polymerization initiator; Step 103, during the immersion process, applying ultrasonic treatment to the suspension system formed by the inorganic mineral substrate and the mixed solution; Step 104, heating the immersed inorganic mineral substrate under the condition that the organic solvent is boiling and forms a reflux, triggering the thermal polymerization initiator to cause in-situ polymerization of the base monomer and the crosslinking agent in the pore or interlayer domain of the inorganic mineral substrate, and inducing a polymerization-induced phase separation process by the porogen; the reflux absorbs the reaction heat released by the in-situ polymerization; Step 105, washing and drying to obtain an adsorbent; wherein the organic functional agent is formed by in-situ polymerization, and a microporous polymer network is physically embedded in the pore or interlayer domain; And the inorganic mineral substrate is bentonite or diatomite; the organic functional agent is di(2-ethylhexyl)phosphoric acid; the base monomer is styrene; the crosslinking agent is divinylbenzene; and the porogen is a poor solvent selected from one of a long-chain fatty alcohol and a saturated alkane.

2. The method for preparing an adsorbent for efficient separation of indium and germanium in a zinc solution according to claim 1, characterized in that, The porogen is a poor solvent; in step 104, the polymerization-induced phase separation process includes: as the base monomer is converted into a polymer network, the solubility of the polymer network in the poor solvent decreases and phase separation occurs, forming a polymer-rich solid phase skeleton and a liquid phase microzone rich in the poor solvent; the washing in step 105 is also used to remove the poor solvent and the liquid phase microzone.

3. The method for preparing an adsorbent for efficient separation of indium and germanium in a zinc solution according to claim 1, characterized in that, In step 103, the frequency of the ultrasonic treatment is 20 kHz to 40 kHz, and the power density of the ultrasonic treatment is 10 W / L to 100 W / L.

4. The method for preparing an adsorbent for efficient separation of indium and germanium in a zinc solution according to claim 1, characterized in that, The heating in step 104 is performed in a reactor equipped with a reflux condenser, and an external heating temperature higher than the boiling point of the organic solvent is set.

5. The method for preparing an adsorbent for efficient separation of indium and germanium in a zinc solution according to claim 1, characterized in that, The method also comprises, between step 101 and step 102, a step of acid activation treatment of the inorganic mineral substrate; the acid activation treatment is carried out in a solution of sulfuric acid at 1 mol / L to 2 mol / L and at 80 to 90 °C for 2 hours.

6. The method for preparing an adsorbent for efficient separation of indium and germanium in a zinc solution according to claim 5, characterized in that, The method further comprises step 601 of collecting an acid washing liquid generated by the acid activation treatment, the acid washing liquid containing metal ions dissolved from the inorganic mineral substrate, and step 602 of, before step 102, using the acid washing liquid or a treatment product thereof to perform surface modification on the inorganic mineral substrate subjected to the acid activation treatment, to form adsorption sites of the metal ions on the surface of the pore or interlayer domain of the inorganic mineral substrate.

7. The method for preparing an indium-germanium high-efficiency separation adsorbent in zinc solution according to claim 1, characterized in that, The method further comprises, before step 102, pre-fixing the thermal polymerization initiator on the surface of the pore or interlayer domain of the inorganic mineral substrate by chemical bonding, the mixed solution in step 102 not containing the thermal polymerization initiator, and the in-situ polymerization in step 104 being triggered by the thermal polymerization initiator fixed on the surface of the inorganic mineral substrate.

8. The method for preparing an adsorbent for efficient separation of indium and germanium in a zinc solution according to claim 1, characterized in that, The method further comprises, prior to step 103, step 901, determining the effective pore volume of the inorganic mineral substrate of step 101 ; and in step 103, the total amount of application of the mixed solution used for impregnation is dynamically determined based on the effective pore volume The total amount of application satisfies the following relationship with the effective pore volume : wherein, is a control coefficient, and the value of the control coefficient ranges from 0.90 to 0.

98.

9. The method according to claim 6, wherein the method is characterized by, The inorganic mineral substrate is bentonite or diatomite, the metal ions dissolved from the inorganic mineral substrate include aluminum ions or iron ions, and the surface modification in step 602 includes: adjusting the pH value of the acidic washing solution to the range of 2.5 to 4.0, so that the aluminum ions or iron ions are adsorbed on the surface of the inorganic mineral substrate in the form of polynuclear hydroxyl complexes.

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