A conditioning agent, its preparation method, and its application in the preparation of porous aluminosilicate ceramics.
By using a conditioning agent composed of aluminum smelting slag flue ash and high molecular polymers, the complex preparation process of aluminosilicate porous ceramics has been solved, achieving process simplification, energy consumption reduction, and hazardous waste resource utilization, while improving the control effect of pore structure and mechanical properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGXI HUAGAN ENVIRONMENTAL TECH R & D CO LTD
- Filing Date
- 2026-04-09
- Publication Date
- 2026-06-30
AI Technical Summary
Existing aluminosilicate porous ceramics preparation processes are complex, require optimization of various additive ratios, have long research and development cycles and high costs, and are difficult to achieve specific pore size distributions and chemical stability.
A conditioning agent composed of aluminum smelting slag flue ash and high molecular polymer is used as a single agent to replace traditional multi-component additives. Through a thermo-chemical-structural synergistic transformation mechanism, mullite, calcium feldspar and potassium sodium feldspar low eutectic products are generated at high temperature to achieve pore-forming, reinforcing and bonding functions.
The process was simplified, energy consumption was reduced, precise control of pore structure and mechanical properties was achieved, the research and development cycle was shortened, and hazardous waste was recycled and chemically stabilized.
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Figure CN122301567A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solid waste utilization, and more particularly to a conditioning agent, its preparation method, and its application in the preparation of aluminosilicate porous ceramics. Background Technology
[0002] Aluminosilicate porous ceramics, as a functional material with a three-dimensional interconnected pore structure, have broad application prospects in construction, environmental protection, and chemical industries due to their excellent thermal insulation, sound absorption, filtration, and catalytic carrier properties. In existing technologies, the preparation of this type of aluminosilicate porous ceramic typically uses bulk solid waste containing aluminosilicate minerals as the main raw material, including fly ash, smelting slag, and tailings slag; a multi-component composite blending system is added, consisting of pore-forming agents (such as organic matter like starch), binders (such as glass powder, mainly composed of SiO2), reinforcing agents (such as alumina), and mineralizers, and sintered at 1000~1300℃ to prepare porous ceramics for different application scenarios. The process has the following technical drawbacks: ① Existing technologies require simultaneous optimization of the ratio of various additives such as pore-forming agents, binders, reinforcing agents, and mineralizers. There are complex physicochemical interactions between the components, and the optimal process parameters often need to be determined through a large number of orthogonal experiments, resulting in long development cycles and high experimental costs; ② For functional porous ceramics with specific pore size distribution, strength requirements, or chemical stability, the existing compound system needs to introduce more functional additives, which further increases the complexity of the formulation and the difficulty of process control. Summary of the Invention
[0003] This invention provides a conditioning agent, its preparation method, and its application in the preparation of aluminosilicate porous ceramics. The conditioning agent uses aluminum smelting slag flue ash as the core component and is combined with specific types and proportions of high molecular polymers. It can replace the traditional complex multi-component additive system as a single agent and achieve multiple functions such as pore formation, reinforcement, and bonding in the preparation of aluminosilicate porous ceramics.
[0004] This invention provides a conditioning agent comprising the following raw materials in parts by weight: The aluminum smelting slag flue dust consists of 94-97.5 parts, non-ionic water-soluble polymer 2-6 parts, and polyacrylate 0.5-2.5 parts. The aluminum smelting slag flue ash contains Al2O3, SiO2, F salt and Cl salt.
[0005] In some specific embodiments, the mass content of Al2O3 in the aluminum smelting slag flue ash is 25%~55%, the mass content of SiO2 is 5%~15%, and the total mass content of fluorine and chlorine in F salt and Cl salt is 6%~20%.
[0006] In some specific embodiments, the nonionic water-soluble polymer includes at least one of polyvinyl alcohol, polyethylene glycol, and carboxymethyl cellulose.
[0007] In some specific embodiments, the polyacrylate includes at least one of ammonium polyacrylate, sodium polyacrylate, and ammonium polymethacrylate.
[0008] A second aspect of the present invention also provides a method for preparing the above-mentioned conditioning agent, comprising the following steps: The aluminum smelting slag flue ash was ball-milled and mixed with water to obtain the main slurry; The main slurry, nonionic water-soluble polymer, and polyacrylate are mixed to obtain a conditioning slurry; The conditioning agent slurry was spray-dried to obtain dried granules; The dried particles are sieved and dried to obtain a conditioning agent.
[0009] In some specific embodiments, the particle size of the ball-milled powder is <75μm.
[0010] In some specific embodiments, the temperature at which the aluminum smelting slag flue ash is mixed with water after ball milling is 0~5℃.
[0011] In some specific embodiments, the spray drying conditions are: inlet temperature 150~200℃ and outlet temperature 80~120℃.
[0012] In some specific embodiments, after drying, the process further includes: particle size classification to obtain conditioning agents with particle sizes of <74μm, 74~150μm, 150~250μm, 250~425μm, 425~850μm, and >850μm.
[0013] A third aspect of the present invention also provides the application of the above-mentioned conditioning agent in the preparation of aluminosilicate porous ceramics.
[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention creatively proposes an integrated technical route of "single agent, multi-functional - endogenous energization of hazardous waste": it breaks through by using aluminum smelting flue ash as a conditioning agent for aluminosilicate porous ceramics. Through a "thermal-chemical-structural" synergistic transformation mechanism, it achieves the internal fuel utilization of residual carbon and the directional activation of the fluorine-chloride salt pore-forming agent function, while innovatively retaining and regulating the Al2O3-SiO2-F-Cl-K-Na-Ca multi-component system. Through high-temperature aluminosilicate reconstruction reaction and gas-solid-liquid multiphase interface engineering optimization, the above components are reacted in situ in the range of 1000-1300℃ to generate mullite, calcium feldspar and potassium sodium feldspar low eutectic material, which are transformed into ceramic reinforcing phase, high-temperature bonding phase and in-situ pore-forming source, realizing the reconstruction of the formulation system of "one agent replacing multiple agents". Attached Figure Description
[0015] The above and other objects, features, and advantages of the invention will be apparent from the following description of preferred embodiments illustrating the gist of the invention and its use, and the accompanying drawings, in which: Figure 1 This is a macroscopic morphology diagram of the aluminosilicate porous ceramic in Example 1.
[0016] Figure 2 This is a scanning electron microscope (SEM) image of the aluminosilicate porous ceramic in Example 1.
[0017] Figure 3 This is a macroscopic morphology diagram of the aluminosilicate porous ceramic in Example 2.
[0018] Figure 4 This is a scanning electron microscope (SEM) image of the aluminosilicate porous ceramic in Example 2.
[0019] Figure 5 This is a scanning electron microscope (SEM) image of the aluminosilicate porous ceramic in Example 3.
[0020] Figure 6 This is a macroscopic morphology diagram of the aluminosilicate porous ceramic in Comparative Example 1.
[0021] Figure 7 This is a scanning electron microscope (SEM) image of the aluminosilicate porous ceramic in Comparative Example 1. Detailed Implementation
[0022] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments described below are for illustrative purposes only and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following embodiments, conditions and methods known in the art can be used for processing.
[0023] This invention provides a conditioning agent comprising the following raw materials in parts by weight: The flue dust from aluminum smelting slag consists of 94-97.5 parts, non-ionic water-soluble polymer 2-6 parts, and polyacrylate 0.5-2.5 parts. The aluminum smelting slag flue ash contains Al2O3, SiO2, F salt and Cl salt.
[0024] The conditioning agent of this invention uses aluminum smelting flue ash as the main raw material, with a small amount of additives, to prepare a conditioning agent for aluminosilicate porous ceramics. This conditioning agent has the following advantages: ① Aluminum smelting flue ash has a certain calorific value, and using it as a conditioning agent for aluminosilicate porous ceramics can effectively reduce the energy consumption required for ceramic sintering during the calcination process; ② Aluminum smelting flue ash is a solid hazardous waste. This invention uses it as a conditioning agent for aluminosilicate-based porous ceramics, and through a high-temperature aluminosilicate reconstruction reaction, it solidifies potential pollutants (fluorides, heavy metals, etc.) in the flue ash into the ceramic lattice or glass phase, achieving chemical stabilization and harmlessness of hazardous components; at the same time, it utilizes its chemical calorific value to replace traditional additives, achieving the circular economy goal of "treating waste with waste and resource utilization of hazardous waste," thus addressing the solid waste issues of the aluminum smelting industry. The reduction provides a new path; ③ The Al2O3, SiO2 and F and Cl salts contained in the conditioning agent of the present invention can effectively replace the multi-component system of reinforcing agent-pore-forming agent-mineralizing agent in the traditional formula, realize the synergistic effect of the three functions, and significantly improve the raw material compatibility of the conditioning agent; ④ In the downstream production process of porous ceramics, the chemical composition and functional effect of the single conditioning agent of the present invention have a deterministic mapping relationship. Only the three key parameters of the mixing ratio (usually 5%~40%), the particle size of the conditioning agent, and the sintering temperature need to be adjusted to achieve precise control of pore structure and mechanical properties. This single variable dominant feature greatly simplifies the process development process and shortens the research and development cycle.
[0025] In some embodiments, aluminum smelting slag flue ash can be selected from aluminum smelting slag flue ash with hazardous waste code HW48 (321-034-48).
[0026] In some embodiments, the mass content of Al2O3 in the aluminum smelting slag flue ash is 25%~55%, the mass content of SiO2 is 5%~15%, and the total mass content of fluorine and chlorine in F salt and Cl salt is 6%~20%.
[0027] In some embodiments, the aluminum smelting slag flue ash contains 4% to 5% CaO, 7% to 10% Na2O, 0.5% to 1.5% Fe2O3, 3% to 6% K2O, and 2% to 4.5% SO3 by mass.
[0028] In some embodiments, the nonionic water-soluble polymer includes at least one of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and carboxymethyl cellulose (CMC).
[0029] In some embodiments, the polyacrylate includes at least one of ammonium polyacrylate (APPA), sodium polyacrylate (PAA), and ammonium polymethacrylate.
[0030] A second aspect of the present invention also provides a method for preparing the above-mentioned conditioning agent, comprising the following steps: The aluminum smelting slag flue ash was ball-milled and mixed with water to obtain the main slurry; The main slurry, nonionic water-soluble polymer, and polyacrylate are mixed to obtain a conditioning slurry; The conditioning agent slurry was spray-dried to obtain dried granules; The dried particles are sieved and dried to obtain a conditioning agent.
[0031] In some embodiments, the particle size of the ball-milled powder is <75 μm.
[0032] In some embodiments, the temperature at which the aluminum smelting slag flue ash is mixed with water after ball milling is 0~5°C. In this invention, adding water to the ball-milled aluminum smelting slag flue ash at a low temperature of 0~5°C for slurry preparation can prevent the AlN in the aluminum smelting slag flue ash from reacting with water and releasing ammonia gas.
[0033] In some embodiments, the spray drying conditions are: inlet temperature 150~200℃ and outlet temperature 80~120℃. As an example, the inlet temperature can be 150℃, 160℃, 170℃, 180℃, 190℃, and 200℃, etc., and the outlet temperature can be 80℃, 90℃, 100℃, 110℃, and 120℃, etc.
[0034] In this invention, the spray drying can be carried out using conventional methods in the art. In some embodiments, the spray drying can be centrifugal spray drying or atomization drying, with a rotation speed of 8000~18000 rpm.
[0035] In some embodiments, after drying, the process further includes: particle size classification to obtain conditioning agents with particle sizes of <74μm, 74~150μm, 150~250μm, 250~425μm, 425~850μm, and >850μm, respectively. The conditioning agents with different particle sizes can affect the porosity and pore size of the target ceramic.
[0036] A third aspect of the present invention also provides the application of the above-mentioned conditioning agent in the preparation of aluminosilicate porous ceramics.
[0037] In some embodiments, the application includes: Fly ash and conditioning agent are mixed to obtain a mixture; The mixture is granulated, dried and calcined in sequence to obtain aluminosilicate porous ceramics.
[0038] In some embodiments, the mass ratio of the fly ash to the conditioning agent is (60~95):(5~40).
[0039] The calcination conditions are as follows: heating rate of 5-10℃ / min, final temperature of 1100-1300℃, holding time of 1-4h, cooling rate of 5-10℃ / min, and final temperature of 400-500℃. For example, the heating rate can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, and 10℃ / min, etc. The final temperature can be 1100℃, 1150℃, 1200℃, 1250℃, and 1300℃, etc. The holding time can be 1h, 2h, 3h, and 4h, etc. The cooling rate can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, and 10℃ / min, etc. The final temperature can be 400℃, 420℃, 450℃, 480℃, and 500℃, etc.
[0040] In some embodiments, calcination can be carried out in an electric furnace.
[0041] In some embodiments, after calcination is completed, the power supply to the electric furnace is turned off, and then the furnace is cooled to below 200°C.
[0042] In this invention, during the calcination process, the aluminosilicate minerals undergo phase reconstruction under the combined action of high temperature and low-melting-point substances and nitrides in the modifier. This reconstruction mainly consists of three stages: ① Room temperature to 650℃: physical dehydration and chemical activation, evaporation of adsorbed water on the particle surface and between layers, and a small amount of condensate in the pores; decomposition of F and Cl salts; initial erosion of the fly ash glass mesh; the appearance of a broad and gentle endothermic peak; and relatively slow weight loss. ② 650-1300℃: the main weight loss zone; multiple endothermic events occur in the DSC (Diverterless Superconducting Carbon) phase; residual carbon oxidation and AlN thermal decomposition create pores; accompanied by the emergence of low-melting-point liquid phases such as feldspar and molten iron phases to form pores; the quartz phase and alumina generate the mullite phase, further crystallizing and vitrifying, thus densifying the pore wall structure. During the calcination process, a reduced heating rate, extended holding time, increased holding temperature, and a reduced cooling rate can promote a more complete reaction, reduce internal thermal stress, make the structure more compact, and improve the strength properties of the porous ceramic.
[0043] In this invention, by controlling the proportion of conditioning agent (5-40%) and the calcination process (1100-1300℃): a high content of Al2O3 (corundum, spinel phase) forms an interpenetrating structure with the fly ash glass network, enhancing the skeletal strength of the porous ceramic; in-situ pores are generated by residual carbon oxidation and AlN thermal decomposition (AlN→Al2O3+N2↑), replacing traditional organic pore-forming agents such as starch; and F... - Cl - By disrupting the silicon-oxygen network and lowering the liquid phase formation temperature, the low-temperature crystallization of mullite, anorthite, and potassium-sodium feldspar phases is promoted; ultimately, a product with a porosity of 30%-70%, compressive strength of 5-20 MPa, and bulk density of 0.5-1.5 g / cm³ is prepared. 3 Aluminosilicate porous ceramics.
[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0045] Example 1 The preparation of the conditioning agent includes the following steps: Aluminum smelting slag flue ash was ball-milled to obtain powder with a particle size <75μm. Then, it was mixed with water at 0℃ to form a main slurry with a concentration of 25wt%. According to the mass ratio of aluminum smelting slag flue ash to non-ionic water-soluble polymer and polyacrylate of 95:4.5:0.5, polyvinyl alcohol and ammonium polyacrylate were added and mixed to obtain a conditioning agent slurry. After spray drying (inlet temperature of 180℃ and outlet temperature of 100℃), dried particles were obtained. After sieving, particles with a particle size of 250-425μm were taken as conditioning agents. The aluminum smelting slag flue ash contains the following raw materials by mass percentage:
[0046] The preparation of porous aluminosilicate ceramics includes the following steps: Fly ash and the conditioning agent with a particle size of 250~425μm prepared above are mixed at a mass ratio of 70:30. Water is added in a disc granulator to form raw material pellets, which are then dried. The dried pellets are placed in an electric furnace and calcined. The temperature is increased to 1250℃ at a rate of 10℃ / min and held for 2 hours. After the holding period, the temperature is decreased to 500℃ at a rate of 5℃ / min. Then the power is turned off and the pellets are cooled to below 200℃ in the furnace before being removed to obtain aluminosilicate porous ceramics.
[0047] The bulk density of the aluminosilicate porous ceramic in Example 1 is 0.67 g / cm³. 3 It has a strength > 5.71 MPa and a porosity of 58.5%, and its macroscopic morphology is as follows. Figure 1 As shown, the SEM image is as follows Figure 2 As shown. By Figure 1 and Figure 2 It can be seen that the surface of this aluminosilicate porous ceramic has many obvious millimeter-sized pores and a glazed gloss, and the interior has micron-sized three-dimensional through-pores.
[0048] Example 2 The preparation of the conditioning agent includes the following steps: Aluminum smelting slag flue ash was ball-milled to obtain powder with a particle size <75μm. Then, it was mixed with water at 0℃ to form a main slurry with a concentration of 25wt%. According to the mass ratio of aluminum smelting slag flue ash to non-ionic water-soluble polymer and polyacrylate of 97:2.5:0.5, polyethylene glycol and sodium polyacrylate were added to obtain a conditioning agent slurry. After spray drying (inlet temperature of 180℃ and outlet temperature of 100℃), dried particles were obtained. After sieving, particles with a particle size of 74-150μm were taken as conditioning agents. The aluminum smelting slag flue ash contains the following raw materials by mass percentage:
[0049] The preparation of porous aluminosilicate ceramics includes the following steps: Fly ash and the conditioning agent with a particle size of 74-150μm prepared above are mixed at a mass ratio of 90:10. Water is added in a disc granulator to form raw material pellets, which are then dried. The dried pellets are placed in an electric furnace and calcined. The temperature is increased to 1250℃ at a rate of 10℃ / min and held for 3 hours. After the holding period, the temperature is decreased to 500℃ at a rate of 5℃ / min. Then the power is turned off and the pellets are cooled to below 200℃ in the furnace before being removed to obtain aluminosilicate porous ceramics.
[0050] The bulk density of the aluminosilicate porous ceramic in Example 2 is 1.28 g / cm³. 3 It has a strength > 9.13 MPa and a porosity of 31.8%, and its macroscopic morphology is as follows. Figure 3 As shown, the SEM image is as follows Figure 4 As shown. By Figure 3 and Figure 4 It can be seen that the surface of the aluminosilicate porous ceramic in Example 2 is semi-matte, indicating that the liquid phase content is relatively low, and the color is darker than that in Example 1. This is because the fly ash content is increased, the content of the color-enhancing element Fe is increased, the color is more reddish-brown, the pore size is smaller than that in Example 1, and the three-dimensional through-pores inside the ceramic are more numerous.
[0051] Example 3 The preparation of the conditioning agent includes the following steps: Aluminum smelting slag flue ash was ball-milled to obtain powder with a particle size <75μm. Then, it was mixed with water at 0℃ to form a main slurry with a concentration of 25wt%. Carboxymethyl cellulose and polymethyl methacrylate were added according to the mass ratio of aluminum smelting slag flue ash to non-ionic water-soluble polymer and polyacrylate of 97:2.5:0.5 to obtain a conditioning agent slurry. After spray drying (inlet temperature 180℃, outlet temperature 100℃), dried particles were obtained. After sieving, particles with a particle size of 250-425μm were taken as conditioning agents. The aluminum smelting slag flue ash contains the following raw materials by mass percentage:
[0052] The preparation of porous aluminosilicate ceramics includes the following steps: Fly ash and the conditioning agent with a particle size of 250-425μm prepared above are mixed at a mass ratio of 70:30. Water is added in a disc granulator to form raw material pellets, which are then dried. The dried pellets are placed in an electric furnace for calcination, heated to 1300℃ at a rate of 10℃ / min, and held at that temperature for 2 hours. After the holding time is completed, the temperature is reduced to 500℃ at a rate of 5℃ / min. Then the power is turned off, and the pellets are cooled to below 200℃ in the furnace before being removed to obtain aluminosilicate porous ceramics.
[0053] The bulk density of the aluminosilicate porous ceramic in Example 3 is 0.58 g / cm³. 3 Its strength is >3.74 MPa, and its porosity is 62.5%. Its SEM image is shown below. Figure 5 As shown, by Figure 5 It can be seen that, in Example 3, the aluminosilicate porous ceramic, due to the increased calcination temperature and more intense reaction in the molten state, exhibited a larger three-dimensional through-pore diameter and a higher proportion compared to Example 1 under the interaction of the pore-forming agent and the liquid phase.
[0054] Comparative Example 1 Fly ash was mixed with Al2O3 powder, carboxymethyl cellulose (CMC) and ammonium polyacrylate (APPA) in a ratio of 80:19:0.8:0.2. Water was added in a disc granulator to form raw material pellets, which were then dried. The dried pellets were placed in an electric furnace and calcined. The temperature was increased to 1200℃ at a rate of 10℃ / min and held for 2 hours. After the holding period, the temperature was decreased to 500℃ at a rate of 5℃ / min. The power was then turned off, and the pellets were cooled to below 200℃ in the furnace before being removed to obtain aluminosilicate porous ceramics.
[0055] The bulk density of the aluminosilicate porous ceramic in Comparative Example 1 was 1.82 g / cm³. 3 It has a strength > 15.3 MPa and a porosity of 18.5%, and its macroscopic morphology is as follows. Figure 6 As shown, the SEM image is as follows Figure 7 As shown. By Figure 6 and Figure 7 It can be seen that the surface of the aluminosilicate porous ceramic in Comparative Example 1 is matte, indicating that no molten liquid phase was present during the sintering process and there are no obvious pores on the surface.
[0056] Although preferred embodiments of the invention have been shown and described, it is conceivable that those skilled in the art can devise various modifications to the invention within the spirit and scope of the appended claims.
Claims
1. A conditioning agent, characterized in that, The raw materials include the following parts by weight: The aluminum smelting slag flue dust consists of 94-97.5 parts, non-ionic water-soluble polymer 2-6 parts, and polyacrylate 0.5-2.5 parts. The aluminum smelting slag flue ash contains Al2O3, SiO2, F salt and Cl salt.
2. The conditioning agent according to claim 1, characterized in that, The aluminum smelting slag flue ash contains 25% to 55% Al2O3 by mass, 5% to 15% SiO2 by mass, and 6% to 20% total fluorine and chlorine by mass in F salt and Cl salt.
3. The conditioning agent according to claim 1, characterized in that, The nonionic water-soluble polymer includes at least one of polyvinyl alcohol, polyethylene glycol, and carboxymethyl cellulose.
4. The conditioning agent according to claim 1, characterized in that, The polyacrylate includes at least one of ammonium polyacrylate, sodium polyacrylate, and ammonium polymethacrylate.
5. A method for preparing the conditioning agent according to any one of claims 1 to 4, characterized in that, Includes the following steps: The aluminum smelting slag flue ash was ball-milled and mixed with water to obtain the main slurry; The main slurry, nonionic water-soluble polymer, and polyacrylate are mixed to obtain a conditioning slurry; The conditioning agent slurry was spray-dried to obtain dried granules; The dried particles are sieved and dried to obtain a conditioning agent.
6. The method for preparing the conditioning agent according to claim 5, characterized in that, The particle size of the ball-milled powder is <75μm.
7. The method for preparing the conditioning agent according to claim 5, characterized in that, The temperature at which the aluminum smelting slag flue ash is mixed with water after ball milling is 0~5℃.
8. The method for preparing the conditioning agent according to claim 5, characterized in that, The spray drying conditions are: inlet temperature 150~200℃, outlet temperature 80~120℃.
9. The method for preparing the conditioning agent according to claim 5, characterized in that, After drying, the process further includes particle size classification to obtain conditioning agents with particle sizes of <74μm, 74~150μm, 150~250μm, 250~425μm, 425~850μm, and >850μm.
10. The use of the conditioning agent according to any one of claims 1 to 4 in the preparation of aluminosilicate porous ceramics.