Antimony-manganese slag composite adsorption material and preparation method thereof

Abstract

The invention relates to the field of solid waste recycling, in particular to an antimony-manganese slag composite adsorption material and a preparation method thereof.The antimony-manganese slag composite adsorption material comprises 50-70 parts of pretreated antimony-manganese slag, 15-25 parts of kaolin, 5-15 parts of glass powder, 15-25 parts of a pore forming agent, 2-5 parts of ammonium dihydrogen phosphate, 0.5-2 parts of manganese carbonate, 0.5-1 part of sodium carboxymethyl cellulose and 40-60 parts of water. And the manganese element in the antimony-manganese slag is converted into an active oxidation center, and the dual effects of adsorption and oxidation are achieved. Gradient distribution is formed through phosphate in-situ conversion, electric field induced oriented growth, magnetic field induction and electric field induction, and the adsorbability and stability of the adsorption material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solid waste resource utilization, in particular, it relates to a composite adsorption material of antimony-manganese slag and a preparation method thereof. BACKGROUND

[0002] The antimony-manganese slag produced in the process of antimony smelting and electrolytic manganese production is a typical hazardous waste or general industrial solid waste of class II. The waste slag not only has a large output and high storage cost, but also contains heavy metal elements such as manganese (Mn) and antimony (Sb), as well as a small amount of associated toxic substances such as arsenic (As) and lead (Pb). Under natural conditions, these heavy metal ions are easily leached into water bodies with rainwater, posing a long-term potential threat to the surrounding ecosystem and drinking water safety.

[0003] Converting solid waste into functional materials to achieve "waste control with waste" is an important development direction in the field of resource recycling. In recent years, the technology of using various industrial waste slag to prepare ceramic materials has made great progress. For example, the Chinese patent application with publication number CN121225980A discloses a method for preparing ceramic materials from lithium slag produced by lithium spodumene acid method. The lithium slag is converted into building ceramics through processes such as magnetic separation, particle size adjustment, and mixing ball milling. The Chinese patent application with publication number CN121377719A discloses a method for preparing low-temperature fast-fired ceramic aggregates from electrolytic manganese slag. By adding borax, talc and other low-temperature fluxes, ceramic aggregates are prepared at 800-1000℃, and the solidification of sulfur and heavy metals is initially achieved. The Chinese patent application with publication number CN116063094A discloses a formula and method for preparing ceramic particles from slag and waste incinerator slag. The mechanical properties of the particles are improved by using organic binders and plasticizers.

[0004] However, the above-mentioned existing technologies mainly focus on preparing solid waste into structural materials (such as building ceramics, aggregates), and the core goal is mechanical properties and volume stability, rather than functional applications. Although some patents mention the solidification of heavy metals, it is limited to physically encapsulating harmful elements in the ceramic matrix to prevent leaching, and the adsorption function of the material is not designed specifically. In other words, the existing technology has achieved "harmless solid waste", but has not achieved "functional solid waste".

[0005] Furthermore, Chinese patent applications with publication numbers CN106215869B and CN106268656A disclose a technology for combining porous silica / alumina ceramics with metal-organic framework materials, significantly improving the adsorption performance of the materials. Chinese patent application CN111662553A proposes a method for in-situ growth of various MOFs using porous ceramic microspheres as a carrier. This combines the high adsorption capacity of MOFs with the high strength and easy recyclability of the ceramic carrier. However, the ceramic raw materials are mostly high-purity industrial raw materials (such as alumina and silica), resulting in higher costs, and it does not involve the utilization of complex industrial waste.

[0006] In summary, existing technologies for preparing functional materials from complex solid wastes such as antimony and manganese slag mainly suffer from the following technical problems: High-temperature sintering can dissolve most heavy metals into the ceramic matrix, but for amphoteric elements like antimony (Sb), the risk of leaching remains under long-term acidic or alkaline environments. Current technologies mainly rely on "physical encapsulation" (such as vitrification), but if the material is damaged by external forces or undergoes chemical corrosion during use, the internal heavy metals still risk being released. How to transform harmful antimony into a chemically stable mineral phase and simultaneously build adsorption capabilities in this process remains a technical challenge that current technologies have not yet solved.

[0007] Therefore, developing an adsorption ceramic material and its preparation method that can fully utilize the active components in antimony-manganese slag, achieve in-situ stabilization and functionalization of heavy metals, possess synergistic oxidation-adsorption dual functions, have a simple preparation process and controllable microstructure, is of great practical significance and application value for promoting the resource utilization of solid waste and the in-depth treatment of heavy metal wastewater. Summary of the Invention

[0008] The purpose of this invention is to provide an antimony-manganese slag composite adsorbent material that converts the manganese element in the antimony-manganese slag into active oxidation centers, thus having the dual functions of adsorption and oxidation.

[0009] Another objective of this invention is to provide a method for preparing an antimony-manganese slag composite adsorbent material, which forms a gradient distribution through in-situ phosphate conversion and electric field-induced directional growth, magnetic field induction and electric field induction, thereby improving the adsorption capacity and stability of the adsorbent material.

[0010] The technical problem solved by this invention is achieved by the following technical solution.

[0011] On one hand, embodiments of the present invention provide an antimony-manganese slag composite adsorbent material, which, by weight, comprises the following raw materials: The pretreatment process includes 50-70 parts antimony-manganese slag, 15-25 parts kaolin, 5-15 parts glass powder, 15-25 parts pore-forming agent, 2-5 parts ammonium dihydrogen phosphate, 0.5-2 parts manganese carbonate, 0.5-1 part sodium carboxymethyl cellulose, and 40-60 parts water.

[0012] In some embodiments of the present invention, the raw materials include the following by weight: The pretreated antimony-manganese slag consists of 60 parts, kaolin 20 parts, glass powder 10 parts, pore-forming agent 20 parts, ammonium dihydrogen phosphate 3 parts, manganese carbonate 1 part, sodium carboxymethyl cellulose 0.8 parts, and water 50 parts.

[0013] In some embodiments of the present invention, the pretreatment steps for the antimony-manganese slag include: The antimony slag and manganese slag after impurity removal are crushed to a particle size of <5mm and washed in a multi-stage countercurrent manner. Lime and ammonium dihydrogen phosphate are added in sequence and stirred for 1-2 hours. Then, the mixture is ball-milled in a wet stirred ball mill for 4-8 hours and dried to obtain the pretreated antimony-manganese slag. In some embodiments of the present invention, the amount of lime added is 3%-6% of the dry residue mass; the amount of ammonium dihydrogen phosphate added is 1%-2% of the dry residue mass.

[0014] On the other hand, embodiments of the present invention provide a method for preparing an antimony-manganese slag composite adsorbent material, comprising the following steps: Pretreated antimony-manganese slag, kaolin, glass powder, pore-forming agent, sodium carboxymethyl cellulose and water are added to a mixing tank according to the specified ratio and stirred to obtain a slurry; The slurry is added into the mold and placed in a magnetic field until the slurry initially solidifies; Demolding, freeze-drying, segmented sintering in a microwave sintering furnace, cooling, and obtaining a porous matrix; The porous matrix is ​​immersed in the precursor solution, sonicated for 30-40 minutes, and then dried. The dried porous matrix was placed in an ethanol-water solution, then placed in a DC electric field for 6-8 hours, washed, and dried. The adsorbent material is obtained by plasma treatment for 8-10 minutes. In some embodiments of the present invention, the precursor solution comprises: The solvent consists of 0.1-0.2 mol / L copper nitrate trihydrate, 0.05-0.1 mol / L pyromellitic acid, and an aqueous ethanol solution with a volume fraction of 50%.

[0015] In some embodiments of the present invention, the field strength of the magnetic field is 0.5-0.8T, and the processing time is 30-40min.

[0016] In some embodiments of the present invention, segmented sintering includes: Stage 1: Heat from room temperature to 300℃ at a rate of 5℃ / min, and hold at that temperature in air for 30 min; Stage 2: Increase the temperature from 300℃ to 600℃ at a rate of 2℃ / min, and hold at that temperature for 60 min in a reducing atmosphere; Stage 3: Increase the temperature from 600℃ to 950℃ at a rate of 8℃ / min, and hold at that temperature in air for 120min. Stage 4: Cooling with the furnace at a rate of 2℃ / min until 100℃ is reached, followed by steaming for 30 minutes until room temperature is reached.

[0017] In some embodiments of the present invention, the voltage of the DC electric field is 8-10V, and the temperature of the porous substrate is 80-90℃.

[0018] In some embodiments of the present invention, the parameters for plasma processing are: Working gas: O2; Gas flow rate: 50 sccm; RF power: 200W; Processing time: 10min; Vacuum degree: 20Pa.

[0019] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: The adsorbent material provided by this invention converts manganese in antimony-manganese slag into active oxidation centers, and grows α-MnO2 nanocrystals in situ within the pores through atmosphere-controlled sintering. These whiskers possess strong oxidizing properties and can rapidly oxidize highly toxic trivalent antimony Sb(III) in water to less toxic pentavalent antimony Sb(V), solving the common industry problem of low removal efficiency and difficulty in stable fixation of Sb(III) by traditional adsorbents.

[0020] The adsorbent material provided by this invention, through in-situ phosphate conversion and electric field-induced directional growth, forms a gradient functional structure within the material: an outer layer of MnO2 oxide whiskers, a middle layer of manganese phosphate adsorption, and an inner layer of MOF capture. This structure achieves stepwise purification of pollutants from oxidation, adsorption, and capture, significantly improving the adsorbent's comprehensive removal capacity for heavy metals such as lead, cadmium, and antimony.

[0021] The adsorbent preparation method provided by this invention directionally transforms the antimony element in antimony slag into a stable mineral phase. Specifically, by introducing ammonium dihydrogen phosphate, it reacts with antimony oxides during sintering to generate stable mineral phases such as antimony phosphate, which are extremely difficult to dissolve in water, thus eliminating the risk of secondary pollution of antimony element in antimony slag.

[0022] Through multi-stage countercurrent water washing in the pretreatment stage, more than 90% of the soluble Mn²⁺ in the manganese slag is removed. + Wet ball milling further removes residual Mn²⁺. +First, manganese is removed; second, during the sintering process, manganese is transformed into stable MnO2 whiskers and manganese phosphate minerals. The transformed manganese phosphate and MnO2 whiskers become new adsorption active centers, achieving a unity of stabilization and functionalization.

[0023] Microwave sintering is employed, utilizing the microwave absorption characteristics of metal oxides in antimony-manganese slag to achieve simultaneous and rapid heating both inside and outside the material. This reduces the sintering temperature, shortens the sintering time, and lowers overall energy consumption.

[0024] During the matrix forming process, applying a magnetic field can induce ferromagnetic minerals in antimony-manganese slag to align under the influence of a steady magnetic field, forming an anisotropic structure. After sintering, the material forms more developed pore channels and more densely exposed active sites perpendicular to the magnetic field direction, thus improving adsorption performance.

[0025] Applying a DC electric field during crystallization allows the directional migration of negatively charged organic ligands under the influence of the electric field to guide the preferential growth of MOF crystals along the electric field direction, forming a gradient distribution structure that facilitates the stepwise capture of adsorbates. Low-temperature plasma dry surface modification introduces a large number of oxygen-containing functional groups to the surface, further enhancing the adsorption capacity. Detailed Implementation

[0026] 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0028] On one hand, embodiments of the present invention provide an antimony-manganese slag composite adsorbent material, which, by weight, comprises the following raw materials: 50-70 parts of pretreated antimony-manganese slag, 15-25 parts of kaolin, 5-15 parts of glass powder, 15-25 parts of pore-forming agent, 2-5 parts of ammonium dihydrogen phosphate, 0.5-2 parts of manganese carbonate, 0.5-1 parts of sodium carboxymethyl cellulose, and 40-60 parts of water.

[0029] A preferred embodiment, by weight, comprises the following raw materials: 60 parts pretreated antimony-manganese slag, 20 parts kaolin, 10 parts glass powder, 20 parts pore-forming agent, 3 parts ammonium dihydrogen phosphate, 1 part manganese carbonate, 0.8 parts sodium carboxymethyl cellulose, and 50 parts water. The pore-forming agent is starch or PMMA.

[0030] The functions of each raw material are as follows: Pretreated antimony-manganese slag provides an active manganese source. The manganese oxides it contains, such as MnO2, Mn2O3, and Mn3O4, can be converted in situ into α-MnO2 nanocrystals after atmosphere-controlled and microwave sintering. It also provides a silicon-aluminum framework; SiO2 and Al2O3 in the antimony-manganese slag are the main framework components of the matrix, forming a stable silicate network after high-temperature sintering, imparting mechanical strength to the material. The iron-manganese oxides (such as magnetite) in the antimony-manganese slag have weak magnetism and can be oriented during magnetic field forming, forming an anisotropic structure. The original antimony in the antimony-manganese slag is converted into antimony phosphate under the action of phosphates and is dissolved in the matrix, no longer dissolving.

[0031] Kaolin imparts good plasticity and binding properties to the material during the green body forming stage, facilitating slip casting or pressing. After drying, it provides sufficient green body strength, preventing cracking during handling and before sintering. It provides Al2O3, which, together with SiO2 in antimony-manganese slag, forms reinforcing phases such as mullite, improving the strength of the sintered body. It promotes liquid phase formation and lowers the sintering temperature.

[0032] Glass powder melts into a liquid phase at around 950℃, filling the gaps between particles and promoting densification. Through a liquid-phase sintering mechanism, the sintering temperature is lowered by 100-150℃. The resulting glassy phase, formed upon cooling, firmly binds the particles together. This glassy phase can also physically encapsulate residual heavy metals, further reducing the risk of leaching.

[0033] Sodium carboxymethyl cellulose prevents the sedimentation of solid particles in the slurry, maintaining its uniformity. It adjusts the slurry viscosity to suit slip casting. It improves the drying strength of the green body, preventing cracking. It assists in pore formation, completely decomposing and volatilizing at high temperatures, leaving micropores.

[0034] The pore-forming agent (starch / PMMA microspheres) leaves behind 10-30 μm macropores after high-temperature decomposition, serving as a rapid channel for wastewater to enter the material. This forms a rich porous structure, providing space for MOF loading.

[0035] Ammonium dihydrogen phosphate reacts with antimony oxides at high temperatures to form antimony phosphate rock, transforming easily soluble antimony into a stable mineral phase that is extremely insoluble in water, thus solidifying the antimony element; it also reacts with Mn²⁺ leached from antimony-manganese slag. + The reaction produces manganese phosphate. The P=O and PO groups on the surface of manganese phosphate react with heavy metal ions (Pb²⁺). + Cd² + Sb(V) has strong complexing ability and becomes the main adsorption active center of the intermediate layer. Phosphate can also act as a binder, forming a phosphate glass phase at high temperature, promoting sintering and densification.

[0036] Manganese carbonate induces whisker growth. During the weak reducing-oxidizing atmosphere transition, it induces the preferential growth of MnO2 in a specific direction, forming nanocrystals. Additional active manganese is provided to enhance the thickness and activity of the oxide layer.

[0037] The pretreatment steps for antimony-manganese slag include: crushing the impurity-removed antimony slag and manganese slag to a particle size of <5mm, washing them in a multi-stage countercurrent manner; adding lime and ammonium dihydrogen phosphate in sequence, stirring and reacting for 1-2 hours, then ball milling in a wet stirred ball mill for 4-8 hours, and drying to obtain the pretreated antimony-manganese slag. Manganese slag contains a large amount of soluble Mn²⁺ + NH4 + SO4² - It can be removed through multi-stage countercurrent washing. Ca(OH)2 can further neutralize residual acid and remove residual Mn²⁺. + Antimony is fixed in the form of hydroxides or manganese ferrates; phosphate ions react with antimony oxides on the slag surface to generate antimony phosphate or antimony phosphate precursors with extremely low solubility, thus achieving pre-stabilization of antimony; heavy metals such as arsenic and antimony are pre-cured through chemical methods to prevent their dissolution in subsequent aqueous phase treatment. During wet ball milling, the material particles continuously generate new surfaces, which helps to stabilize residual Mn²⁺. + NH4 + It produces an adsorption and encapsulation effect, further reducing its leaching concentration to below the national standard.

[0038] In some embodiments of the present invention, the amount of lime added is 3%-6% of the dry residue mass; the amount of ammonium dihydrogen phosphate added is 1%-2% of the dry residue mass.

[0039] On the other hand, embodiments of the present invention provide a method for preparing an antimony-manganese slag composite adsorbent material, comprising the following steps: Pretreated antimony-manganese slag, kaolin, glass powder, pore-forming agent, sodium carboxymethyl cellulose and water are added to a mixing tank according to the specified ratio and stirred to obtain a slurry; The slurry is added to a non-metallic mold and placed in a magnetic field until it initially solidifies. Ferromagnetic minerals (such as magnetite and iron-manganese oxides) in the antimony-manganese slag align under the influence of the magnetic field, forming an anisotropic structure. After subsequent sintering, the material develops more developed pore channels and exposes more densely packed active sites in the direction perpendicular to the magnetic field. Demolding, freeze-drying, and segmented sintering in a microwave sintering furnace, followed by cooling, yields a porous matrix. Freeze-drying prevents particle agglomeration and surface hardening, preserving the original loose structure and facilitating subsequent gas venting and pore formation. Microwave sintering utilizes the metal oxides in the antimony-manganese slag, which act as excellent microwave absorbers, preferentially heating to form micro-hot spots and promoting localized reactions. Simultaneous internal and external heating results in low thermal stress, reducing material cracking, and shortening the total sintering time by more than 60% compared to traditional resistance furnaces.

[0040] The porous matrix is ​​immersed in the precursor solution, ultrasonically treated for 30-40 minutes, and then dried. The microjets generated by ultrasonic cavitation forcefully inject the solution into the depth of the micropores to achieve uniform loading and activate the surface of the pore walls. Under the action of an electric field, the negatively charged organic ligands migrate directionally towards the positive electrode, forming a concentration gradient in the pores. The MOF crystals preferentially grow along the direction of the electric field, forming a gradient distribution structure. The dried porous matrix was placed in an ethanol-water solution, then placed in a DC electric field for 6-8 hours, washed, and dried. The adsorbent material is obtained by plasma treatment for 8-10 minutes. Plasma treatment can not only introduce a large number of oxygen-containing functional groups (-OH, -COOH) onto the material surface, enhancing its complexation ability with heavy metals, but also remove trace amounts of residual organic matter within the pores, exposing more adsorption sites.

[0041] The adsorbent material prepared by the above method forms the following gradient structure: The outer layer is α-MnO2 nanocrystals with a thickness of about 1-5 μm. As an oxide layer, it can quickly oxidize the highly toxic Sb(III) to the less toxic Sb(V). The intermediate layer is a manganese phosphate / silicate composite layer with a thickness of approximately 10-30 μm, serving as an adsorption layer. PO groups react with Sb(V) and Pb²⁻. + A stable complex is formed; The inner layer is a MOF crystal with a thickness of approximately 0.5-2 μm, which achieves deep purification of heavy metals through coordination. The antimony-manganese slag skeleton serves as the matrix, providing mechanical strength and dissolving the remaining heavy metals in the antimony-manganese slag.

[0042] When this adsorbent material is used, wastewater containing heavy metals rapidly diffuses into the interior through the material's macropores (>10 μm). Upon contact with the outer MnO2 whiskers, Sb(III) is oxidized to Sb(V). The oxidized Sb(V) is then complexed and adsorbed by the PO groups of the intermediate manganese phosphate layer. A small amount of residual heavy metals continues to diffuse into the inner layer and is firmly captured by the open metal sites of the MOF through coordination.

[0043] In some embodiments of the present invention, the precursor solution comprises: The solvent consists of 0.1-0.2 mol / L copper nitrate trihydrate, 0.05-0.1 mol / L pyromellitic acid, and an aqueous ethanol solution with a volume fraction of 50%.

[0044] In some embodiments of the present invention, the field strength of the magnetic field is 0.5-0.8T, and the processing time is 30-40min.

[0045] In some embodiments of the present invention, segmented sintering includes: Stage 1: Heating from room temperature to 300℃ at a rate of 5℃ / min, and holding at this temperature in air for 30 min; the main purpose of this stage is to remove free water and water of crystallization. Stage 2: The temperature is increased from 300℃ to 600℃ at a rate of 2℃ / min, and held in a reducing atmosphere for 60 min; this induces partial reduction of manganese oxides to generate Mn3O4 crystal nuclei. Stage 3: Heating from 600℃ to 950℃ at a rate of 8℃ / min and holding in air for 120min; rapid sintering and densification, while Mn3O4 on the surface is oxidized to form α-MnO2 whiskers; heavy metal solidification also occurs in this stage; phosphate reacts with Sb to form antimony phosphate; excess phosphate reacts with Mn to form manganese phosphate. Stage 4: Cooling with the furnace at a rate of 2℃ / min until 100℃ is reached, followed by steaming for 30 minutes until room temperature is reached.

[0046] In some embodiments of the present invention, the voltage of the DC electric field is 8-10V, and the temperature of the porous substrate is 80-90℃.

[0047] In some embodiments of the present invention, the parameters for plasma processing are: Working gas: O2; Gas flow rate: 50 sccm; RF power: 200W; Processing time: 10min; Vacuum degree: 20Pa.

[0048] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0049] Example 1 Pretreatment of antimony-manganese slag: Antimony slag originates from the volatile slag produced during the antimony ore smelting process. It is the slag produced by the volatilization roasting of antimony ore in a vertical shaft furnace. It is in the form of lumps and mainly contains Fe2O3, SiO2, CaO, Al2O3, etc.

[0050] Manganese slag is the residue produced during the electrolytic manganese production process, after manganese carbonate ore powder is leached with sulfuric acid and then separated by pressure filtration. Its main chemical components are: SiO2, CaSO4·2H2O (gypsum), Al2O3, Fe2O3, MnO, etc.

[0051] Impurities such as plastic, wood chips, and metal pieces are manually removed. A jaw crusher is used to crush the antimony-manganese slag to a particle size of <5mm, facilitating subsequent washing and ball milling.

[0052] A four-stage countercurrent washing tank was used to wash antimony-manganese slag (the mass ratio of antimony slag to manganese slag was 1:1), with a liquid-to-solid ratio of 2.5:1 (mass ratio), and each stage was stirred for 30 minutes.

[0053] Lime: Add 5% by weight of the dry weight of the washed residue; ammonium dihydrogen phosphate: Add 1.5% by weight of the dry weight of the washed residue. React in a stirred tank for 2 hours, maintaining the pH at 8-9.

[0054] A wet-mixed ball mill was used, with a ball-to-material ratio of 10:1 and a solid-to-liquid ratio of 1:5 (material: deionized water). The rotation speed was 150-200 rpm. Milling was carried out for 6 hours. A small amount of sodium polyacrylate (0.1% of the material mass) was added during the milling process.

[0055] The ball-milled slurry undergoes solid-liquid separation, and the filter cake is spray-dried (inlet air temperature 250-300℃, outlet air temperature 100-110℃) to rapidly dehydrate and obtain powder with good sphericity. The dried powder is then passed through a 400-mesh sieve to ensure that all particles are less than 38μm in size.

[0056] Determine the raw material ratio: The pretreated antimony-manganese slag consists of 60 parts, kaolin 20 parts, glass powder 10 parts, pore-forming agent (starch) 20 parts, ammonium dihydrogen phosphate 3 parts, manganese carbonate 1 part, sodium carboxymethyl cellulose 0.8 parts, and water 50 parts.

[0057] Prepare the adsorbent material according to the following steps: Pretreated antimony-manganese slag, kaolin, glass powder, pore-forming agent, sodium carboxymethyl cellulose and water were added to a mixing tank according to the specified ratio. The mixing speed was 500 rpm and the time was 2 hours to obtain a uniform slurry. Add the slurry into a non-metallic mold, apply a steady magnetic field of 0.8 T around the mold, keep the magnetic field direction perpendicular to the preset adsorption working surface, keep the magnetic field for 30 minutes, and remove the magnetic field after the slurry has initially solidified. The demolded wet blank was placed in a freeze dryer, pre-frozen at -40℃ for 2 hours; vacuum at 10Pa for 12 hours. The porous matrix is ​​obtained by segmented sintering and cooling in a microwave sintering furnace. The segmented sintering process is as follows: Stage 1: Heat from room temperature to 300℃ at a rate of 5℃ / min, and hold at that temperature in air for 30 min; Phase 2: Increase the temperature from 300℃ to 600℃ at a rate of 2℃ / min, and hold at this temperature for 60 min in a weak reducing atmosphere (N2 + 2% CO). Stage 3: Increase the temperature from 600℃ to 950℃ at a rate of 8℃ / min, and hold at that temperature in air for 120min. Stage 4: Cooling with the furnace at a rate of 2℃ / min until 100℃ is reached, followed by steaming for 30 minutes until room temperature is reached.

[0058] Preparation of precursor solution: 0.2 mol / L copper nitrate trihydrate, 0.1 mol / L trimesic acid, and an aqueous ethanol solution as solvent, with a volume fraction of 50%.

[0059] The porous matrix, which has been cooled to room temperature, is immersed in the precursor solution, sonicated for 30 min at a frequency of 40 kHz, and dried in an oven at 60 °C for 2 hours to concentrate the precursor in the pores. The impregnated and dried porous matrix was placed in a reaction vessel, and a small amount of ethanol solution was added (the liquid level should not exceed 1 / 3 of the total height). Parallel electrodes were placed on both sides of the vessel, an 8V DC electric field was applied, and the reaction vessel was heated in an 80℃ water bath for 8 hours. After treatment, the vessel was washed with ethanol and activated in a 120℃ vacuum drying oven for 4 hours. The adsorbent material was obtained by plasma treatment for 10 minutes with the following parameters: working gas: O2; gas flow rate: 50 sccm; radio frequency power: 200W; treatment time: 10 minutes; vacuum degree: 20Pa. Example 2 The difference from Example 1 is that, Raw material ratio: 50 parts pretreated antimony-manganese slag, 15 parts kaolin, 5 parts glass powder, 20 parts pore-forming agent (starch), 2 parts ammonium dihydrogen phosphate, 0.5 parts manganese carbonate, 0.5 parts sodium carboxymethyl cellulose, and 40 parts water.

[0060] The preparation method is the same as in Example 1.

[0061] Example 3 The difference from Example 1 is that, Raw material ratio: 70 parts pretreated antimony-manganese slag, 25 parts kaolin, 15 parts glass powder, 25 parts pore-forming agent (starch), 5 parts ammonium dihydrogen phosphate, 2 parts manganese carbonate, 1 part sodium carboxymethyl cellulose, and 60 parts water.

[0062] The preparation method is the same as in Example 1.

[0063] Example 4 The difference from Example 1 is that, Raw material ratio: 70 parts pretreated antimony-manganese slag, 20 parts kaolin, 15 parts glass powder, 25 parts pore-forming agent (starch), 5 parts ammonium dihydrogen phosphate, 0.5 parts manganese carbonate, 1 part sodium carboxymethyl cellulose, and 60 parts water.

[0064] The preparation method is the same as in Example 1.

[0065] Example 5 The difference from Example 1 is that, The precursor solution contained 0.1 mol / L copper nitrate trihydrate and 0.05 mol / L trimellitic acid. The remaining raw material ratios and preparation methods were the same as in Example 1.

[0066] Example 6 The difference from Example 1 is that, The precursor solution contained 0.2 mol / L copper nitrate trihydrate and 0.05 mol / L trimellitic acid. The remaining raw material ratios and preparation methods were the same as in Example 1.

[0067] Comparative Example 1 The difference from Example 1 is that, In the preparation of the adsorbent material, no magnetic field was applied, and the remaining steps and raw material ratios were the same as in Example 1.

[0068] Comparative Example 2 The difference from Example 1 is that, In the preparation of the adsorbent material, no electric field was applied, and the remaining steps and raw material ratios were the same as in Example 1.

[0069] Comparative Example 3 The difference from Example 1 is that, In the preparation of the adsorbent material, no magnetic field or electric field was applied, and the remaining steps and raw material ratios were the same as in Example 1.

[0070] Comparative Example 4 The difference from Example 1 is that, In the preparation of the adsorbent material, manganese carbonate was not added to the raw materials; instead, an equal amount of pretreated antimony-manganese slag was used. The remaining steps and raw material ratios were the same as in Example 1.

[0071] Comparative Example 5 The difference from Example 1 is that, In preparing the adsorbent material, ammonium dihydrogen phosphate was not added to the raw materials; instead, an equal amount of pretreated antimony-manganese slag was used. The remaining steps and raw material ratios were the same as in Example 1.

[0072] Experimental Example The adsorbent materials used in the examples and comparative examples were tested according to the test methods in Table 1.

[0073] Table 1

[0074] The test results are shown in Table 2-6.

[0075] Table 2

[0076] Table 2 shows that the porosity of Examples 1-6 is between 48% and 55%, the compressive strength is 17-21 MPa, the specific surface area is 35-43 m² / g, and the overall performance is good.

[0077] Comparative Example 1 (without magnetic field) showed a decrease in porosity to 46.2% and a decrease in specific surface area to 31.5 m² / g, indicating that magnetic field-oriented molding helps to form an ordered pore structure and increase the specific surface area.

[0078] Comparative Example 3 (no magnetic field + no electric field) had the worst performance, with a porosity of only 44.5% and a specific surface area of ​​28.6 m² / g. It can be seen that the synergistic effect of the magnetic field and electric field in the examples can optimize the microstructure of the adsorption material and improve the adsorption performance.

[0079] Comparative Example 4 (without manganese carbonate) had a specific surface area of ​​32.8 m² / g, which was lower than that of Example 1, indicating that the MnO2 whiskers induced by manganese carbonate can increase the specific surface area.

[0080] Comparative Example 5 (without ammonium dihydrogen phosphate) had a specific surface area of ​​29.4 m² / g, which was significantly lower than that of Example 1, indicating that the addition of phosphate can increase the porosity of the adsorbent material and increase the pore structure.

[0081] Table 3

[0082] As can be seen from Table 3, Example 1 achieved a Sb(III) removal rate of 98.2%, a saturated adsorption capacity of 63.5 mg / g, and an adsorption rate constant of 0.042.

[0083] Comparative Example 5 (without ammonium dihydrogen phosphate) showed a removal rate of only 42.6%, a saturated adsorption capacity of only 18.2 mg / g, and the slowest adsorption rate. Ammonium dihydrogen phosphate participated in the formation of the manganese phosphate adsorption layer, enabling highly efficient adsorption. In Comparative Example 5, the absence of phosphate meant that the adsorption material essentially lost its effective adsorption capacity for Sb(III).

[0084] The adsorption performance of Examples 5-6 is lower than that of Example 1. Too low MOF concentration or insufficient ligands will affect the inner layer depth capture capability.

[0085] The removal rate of Comparative Example 3 (no magnetic field + no electric field) was 78.5%, which was lower than that of Example 1, indicating that physical field enhancement helps to improve adsorption efficiency.

[0086] Comparative Example 4 (without manganese carbonate) had a removal rate of 86.2%, which was lower than that of Example 1, indicating that the oxidation of Sb(III) by MnO2 whiskers helps to improve the overall removal rate.

[0087] Table 4

[0088] Table 4 shows that Example 1 affects Pb² + The removal rate reached 96.8%, and the saturated adsorption capacity was 68.5 mg / g, indicating that the adsorption material of this invention has a broad-spectrum adsorption capacity for a variety of heavy metals.

[0089] Comparative Example 5 (without ammonium dihydrogen phosphate) vs. Pb² + The adsorption capacity was only 21.6 mg / g, which was only 31.5% of that in Example 1, highlighting the decisive role of the phosphate layer in the adsorption of heavy metals.

[0090] The adsorption capacity of Comparative Example 3 (no magnetic field + no electric field) was 38.5 mg / g, which was significantly lower than that of Example 1, indicating that the adsorption performance of the adsorption material can be improved by strengthening the physical field.

[0091] Table 5

[0092] Table 5 shows that the Mn leaching concentration in Examples 1-6 is all <0.5 mg / L, and the Sb leaching concentration is <0.1 mg / L, which is far superior to the national standard. This indicates that the adsorbent material provided in these embodiments exhibits good stability of heavy metals in antimony-manganese slag.

[0093] Comparative Example 5 (without ammonium dihydrogen phosphate) showed a Sb leaching concentration as high as 1.15 mg / L, which is 2.3 times the national standard, indicating that ammonium dihydrogen phosphate is a key component for solidifying antimony. Without phosphate, antimony cannot be converted into stable antimony phosphate ore.

[0094] Comparative Example 4 (without manganese carbonate) had a Mn leaching concentration of 1.86 mg / L, which is close to the national standard limit, indicating that the MnO2 whiskers induced by manganese carbonate help stabilize manganese.

[0095] In Comparative Example 3 (no magnetic field + no electric field), the leaching concentrations of Mn and Sb were higher than those in Example 1, indicating that the ordered microstructure formed under the influence of magnetic and electric fields facilitates the solid solution of heavy metals.

[0096] Table 6

[0097] Table 6 shows that Example 1 maintained a removal rate of 84.0% after 5 cycles, demonstrating good cycle stability. Comparative Example 5, however, only maintained a 60.6% removal rate, with a low initial removal rate, indicating that the phosphate-free material itself has poor adsorption capacity and poor cycle performance. Comparative Example 3 maintained a 66.6% removal rate, lower than Example 1, suggesting that physical field enhancement helps form a more stable structure. Ammonium dihydrogen phosphate (MDP) can achieve the dual function of chemical stabilization of antimony and the formation of a manganese phosphate adsorption layer. Without MDP, the material's adsorption of Sb(III) decreased by 71%, and the Sb leaching concentration increased by 18 times, resulting in severe performance degradation. The addition of manganese carbonate is crucial for MnO2 whisker growth and manganese stabilization. Without manganese carbonate, the Mn leaching concentration approached the national standard limit, and the adsorption decreased by 30%.

[0098] Magnetic and electric fields have a significant synergistic enhancing effect. Using either physical field alone can improve performance, but the combined effect of both is optimal. Without a magnetic field, porosity decreases by 12.5%; without an electric field, MOF loading is uneven; and when neither is present, the overall performance declines most significantly.

[0099] In summary, the adsorbent material provided in the embodiments has the following advantages: Physical properties: Porosity 50-55%, compressive strength 18-21 MPa, specific surface area 35-43 m² / g; Adsorption performance: Sb(III) removal rate >98%, saturated adsorption capacity >60 mg / g; Pb² + Adsorption capacity >65mg / g; Environmental safety: heavy metal leaching concentration is far below the national standard; Cyclic stability: removal rate retention rate >80% after 5 cycles.

[0100] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A composite adsorbent material for antimony-manganese slag, characterized in that, By weight, it includes the following ingredients: The pretreatment process includes 50-70 parts antimony-manganese slag, 15-25 parts kaolin, 5-15 parts glass powder, 15-25 parts pore-forming agent, 2-5 parts ammonium dihydrogen phosphate, 0.5-2 parts manganese carbonate, 0.5-1 part sodium carboxymethyl cellulose, and 40-60 parts water.

2. The antimony-manganese slag composite adsorbent material according to claim 1, characterized in that, By weight, it includes the following ingredients: The pretreated antimony-manganese slag consists of 60 parts, kaolin 20 parts, glass powder 10 parts, pore-forming agent 20 parts, ammonium dihydrogen phosphate 3 parts, manganese carbonate 1 part, sodium carboxymethyl cellulose 0.8 parts, and water 50 parts.

3. The antimony-manganese slag composite adsorbent material according to claim 1, characterized in that, The pretreatment steps for the antimony-manganese slag include: The antimony slag and manganese slag after impurity removal are crushed to a particle size of <5mm and washed in a multi-stage countercurrent manner. Lime and ammonium dihydrogen phosphate are added in sequence and stirred for 1-2 hours. Then, the mixture is ball-milled in a wet stirred ball mill for 4-8 hours and dried to obtain the pretreated antimony-manganese slag.

4. The antimony-manganese slag composite adsorbent material according to claim 1, characterized in that, The amount of lime added is 3%-6% of the dry residue mass; the amount of ammonium dihydrogen phosphate added is 1%-2% of the dry residue mass.

5. A method for preparing the antimony-manganese slag composite adsorbent material as described in any one of claims 1-4, characterized in that, Includes the following steps: Pretreated antimony-manganese slag, kaolin, glass powder, pore-forming agent, sodium carboxymethyl cellulose and water are added to a mixing tank according to the specified ratio and stirred to obtain a slurry; The slurry is added into the mold and placed in a magnetic field until the slurry initially solidifies; Demolding, freeze-drying, segmented sintering in a microwave sintering furnace, cooling, and obtaining a porous matrix; The porous matrix is ​​immersed in the precursor solution, sonicated for 30-40 minutes, and then dried. The dried porous matrix was placed in an ethanol-water solution, then placed in a DC electric field for 6-8 hours, washed, and dried. The adsorbent material is obtained by plasma treatment for 8-10 minutes.

6. The preparation method of the antimony-manganese slag composite adsorbent material according to claim 5, characterized in that, The precursor solution comprises: The solvent consists of 0.1-0.2 mol / L copper nitrate trihydrate, 0.05-0.1 mol / L pyromellitic acid, and an aqueous ethanol solution with a volume fraction of 50%.

7. The preparation method of the antimony-manganese slag composite adsorbent material according to claim 5, characterized in that, The magnetic field strength is 0.5-0.8T, and the processing time is 30-40 minutes.

8. The preparation method of the antimony-manganese slag composite adsorbent material according to claim 5, characterized in that, Segmented sintering includes: Stage 1: Heat from room temperature to 300℃ at a rate of 5℃ / min, and hold at that temperature in air for 30 min; Phase 2: Increase the temperature from 300℃ to 600℃ at a rate of 2℃ / min, and hold at that temperature for 60 min in a reducing atmosphere; Stage 3: Increase the temperature from 600℃ to 950℃ at a rate of 8℃ / min, and hold at that temperature in air for 120min. Stage 4: Cooling with the furnace at a rate of 2℃ / min until 100℃ is reached, followed by steaming for 30 minutes until room temperature is reached.

9. The preparation method of the antimony-manganese slag composite adsorbent material according to claim 5, characterized in that, The voltage of the DC electric field is 8-10V, and the temperature of the porous substrate is 80-90℃.

10. The preparation method of the antimony-manganese slag composite adsorbent material according to claim 6, characterized in that, The parameters for plasma treatment are: Working gas: O2; Gas flow rate: 50 sccm; RF power: 200W; Processing time: 10min; Vacuum degree: 20Pa.

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