Industrial solid waste high-performance filling material and preparation method thereof

Abstract

The invention discloses an industrial solid waste high-performance filling material and a preparation method thereof, and relates to the technical field of solid waste resource utilization and building materials. The material is composed of 60-80 wt% of industrial solid waste, 0.1-0.5 wt% of nano graphene oxide, 5-15 wt% of biomass charcoal / phase change microcapsules and a gelling component, a solid waste surface passivation layer is broken and removed through an acid leaching purification-hydrothermal activation synergistic process, and a Si-Al hydrothermal gel shell layer is generated in situ to achieve microscopic chemical bonding; and a spray drying integrated process is adopted to synchronously complete multifunctional modification and pore regulation and control. The material has the following advantages: 1, the mechanical property is obviously improved, the 28-day compressive strength is greater than or equal to 45MPa, and the interface fracture energy is improved by more than 25%; 2, the thermal conductivity is regulated and controlled to be 0.25-0.35 W / (m.K), the sound absorption coefficient is 0.5-0.7, and the CO2 adsorption function is realized; and 3, the process is simplified, the energy consumption is reduced by 30% compared with the traditional method, and the solid waste utilization rate reaches 95% or above. The method is suitable for the engineering fields of building heat preservation, road bases and the like, and solid waste recycling and collaborative preparation of high-performance building materials are achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of solid waste resource utilization and building materials, and particularly relates to a high-performance filling material prepared from coal gangue and fly ash as main raw materials through surface activation, structure regulation and composite modification, and a preparation method thereof. BACKGROUND

[0002] With the acceleration of industrialization, the annual output of solid waste such as coal gangue and fly ash generated by coal mining and thermal power generation is huge. Traditionally, these solid wastes are mostly stored or simply backfilled, which not only occupies a large amount of land resources, but also has environmental risks such as dust and leachate pollution. On the other hand, the demand for filling materials in the fields of building, road, and mine backfilling is huge, and the market mainly relies on natural sand, cement and other resources, which are high in cost and increasingly scarce. Therefore, developing and utilizing industrial solid waste to prepare new high-performance filling materials not only realizes the reduction and resource utilization of solid waste, but also has significant economic and environmental benefits, and has become a research hotspot in the field of solid waste comprehensive utilization and new building materials.

[0003] In the prior art, coal gangue and fly ash are often used as alternative fillers in cement concrete or mine backfilling materials. Typical methods include:

[0004] (1) Direct mechanical grinding: coal gangue / fly ash is ground and mixed with ordinary Portland cement at a certain ratio for backfilling or light brick manufacturing, but the interface bonding performance of the obtained material is insufficient, and the compressive strength and durability are poor;

[0005] (2) Alkali-activated cementitious: using the pozzolanic activity of fly ash and cooperating with alkali activators (such as water glass, sodium hydroxide) to prepare alkali-activated materials, which can partially replace cement, but generally requires high alkalinity, room temperature or high temperature for a long time curing, which is high in production energy consumption and complex in process;

[0006] (3) Chemical modification: surface modification of coal gangue by acid washing or heat treatment to improve its activity, and then mixed with fly ash, cement matrix to prepare composite materials; this method can slightly increase the interface adhesion, but often does not fully consider the micro / nano structure regulation, and the modification steps are more and the cost is higher.

[0007] The above technologies have achieved the resource utilization of coal gangue and fly ash to some extent, but still have the following shortcomings:

[0008] (1) Weak interface bonding: the chemical bonding or physical interlocking of the solid waste filler and the cement matrix is insufficient, which limits the improvement of compressive strength and crack resistance;

[0009] (2) Single function: the existing products mainly meet the filling or basic load bearing requirements, and do not consider the multi-functional requirements such as heat insulation, sound absorption, and carbon capture;

[0010] (3) Process is complex and cost is high: multi-step chemical treatment or high-temperature long-time curing process, which is not conducive to industrialization and large-scale promotion.

[0011] Therefore, there is an urgent need for a simple and efficient process route to deeply activate and structurally optimize modify coal gangue and fly ash to prepare composite filling materials with high strength, high durability and multiple functions to meet the dual needs of modern engineering construction and environmental protection resource utilization. SUMMARY

[0012] The purpose of the present application is to provide an industrial solid waste high-performance filling material and a preparation method to solve the existing problems.

[0013] To solve the above technical problems, the present application is realized by the following technical scheme:

[0014] The present application is a preparation method of an industrial solid waste high-performance filling material, comprising the following steps:

[0015] S1, raw material pretreatment:

[0016] S11, crushing the industrial solid waste powder to a particle size of ≤2mm, and grading by a vibrating screen, collecting the powder of ≤200μm for ball milling;

[0017] S12, adding grinding media to the ball mill to a loading rate of 50-60%, wet milling at a speed of 50-80r / min for 2-3h to obtain a powder with a particle size distribution concentrated in 50-200μm;

[0018] S13, chemically purifying the ball-milled powder to remove free alkali and soluble impurities, and drying to obtain pretreated powder.

[0019] S2, surface activation:

[0020] S21, mixing the pretreated powder with a water glass solution, treating with an ultrasonic disperser, and then performing a hydrothermal reaction to generate a Si-Al hydrothermal gel shell;

[0021] S22, separating, washing and drying the hydrothermal reaction product to obtain surface-activated microspheres.

[0022] S3, composite modification:

[0023] S31, dispersing and adsorbing nano-graphene oxide (GO) on the surface of the surface-activated microspheres;

[0024] S32, synergistically grafting biomass charcoal or phase change microcapsules with GO-microspheres to form a composite slurry;

[0025] S33, drying and shaping the composite slurry to obtain multifunctional composite powder.

[0026] S4, molding and curing:

[0027] S41, mixing and stirring the composite powder with ordinary Portland cement, carbonaceous material, nano-SiO2 and water reducing agent to form a homogeneous slurry;

[0028] S42, pouring the homogeneous slurry into a mold, and performing vibration defoaming, film coating and moisture retention and initial curing;

[0029] S43, standard curing of the preliminary cured test piece to obtain the final product.

[0030] In one embodiment, in step S1, the ball milled powder is impregnated with acid and impurities are removed by continuous filtration, and the filtrate pH is adjusted to neutral, and the precipitate is dewatered by pressure filtration and recycled as secondary resources or safely landfilled.

[0031] In one embodiment, in step S2, the hydrothermal reaction is carried out at 100-120℃ for 2.5-3.5h, and the activated product is separated by centrifugation, washed and dried in a fluidized bed to obtain surface activated microspheres.

[0032] In one embodiment, in step S3, GO is adsorbed on the surface of the microspheres after ultrasonic dispersion and pH adjustment, and biomass charcoal or phase change microcapsules are pretreated and grafted with GO-microspheres, and multifunctional composite powder is obtained by spray drying or hot air circulation drying.

[0033] In one embodiment, in step S4, a staged batching method is used in the batching process, high viscosity active slurry is first prepared, carbonaceous material and nano-SiO2 are then added for low speed stirring, and the balance of water is finally added to adjust the water cement ratio, and air bubbles are eliminated by a vibration table; after molding, the test piece is cured in a constant temperature and humidity box for 24h, and is cured in a standard curing room until the 28th day for testing.

[0034] The industrial solid waste high performance filling material prepared by the above preparation method.

[0035] The present application has the following beneficial effects:

[0036] 1. Significantly improve the mechanical properties and interfacial bonding force:

[0037] The Si-Al hydrothermal gel shell generated in situ by hydrothermal reaction effectively breaks the passivation layer on the surface of the industrial solid waste, introduces a large number of Si-O-Al chemical bonding sites, realizes micro occlusion, and significantly improves the compressive strength and crack resistance of the filling material.

[0038] The 28-day compressive strength is increased by ≥15% compared with the control group, and the interfacial peeling energy (mode II interfacial fracture energy) is increased by >25%.

[0039] 2. Multifunctional performance:

[0040] The thermal conductivity regulation and crack resistance of nano-graphene oxide (GO) are combined with the hierarchical pore structure of biomass char or phase change microcapsules to achieve synergistic effects of thermal management, acoustic energy dissipation, and gas adsorption.

[0041] The overall thermal conductivity of the composite material is reduced by 20-30%, the sound absorption coefficient can reach 0.5-0.7, and the CO2 adsorption capacity reaches 0.5-1.2 mmol / g.

[0042] 3. Process simplification and cost control:

[0043] The combination of acid leaching purification and hydrothermal activation further completes surface activation, reducing the multiple chemical treatments or high-temperature long-time curing steps in traditional processes.

[0044] The combination of multifunctional modification and drying spray process further simplifies the production process, eliminates additional modification steps and separation procedures, and reduces the unit material cost by about 10-20%.

[0045] 4. Improved durability and long-term stability:

[0046] The dense protective layer constructed by Si-Al gel and GO double coating effectively reduces the erosion of alkali calcium silicate phase and freeze-thaw damage, and improves the carbonation resistance and compressive strength retention rate of the material.

[0047] After standard freeze-thaw cycles (–20℃-20℃, 25 times), the compressive strength retention rate is >90%, and the carbonation resistance depth is reduced by about 30% compared to the control.

[0048] 5. Controllable micro / multilayer structure:

[0049] By adjusting the amount of biomass char or phase change capsules and spray drying parameters, the porosity of the material is precisely adjusted, and the pore size distribution shows a three-level structure of micropores <2 nm, mesopores 2-50 nm, and macropores >50 nm, meeting different mechanical and functional requirements.

[0050] In summary, the present application not only realizes efficient resource utilization of industrial solid waste and prepares high-performance, multifunctional filler materials, but also reduces production costs through process simplification, improves material durability and long-term stability, and has significant economic and environmental benefits.

[0051] Of course, any product implementing the present application does not necessarily need to achieve all the advantages described above. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description only show some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0053] Figure 1 Flow chart of the preparation method of the high-performance filling material of industrial solid waste. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0055] In the description of the present application, it should be understood that the terms "upper", "middle", "outer", "inner" and the like indicate the orientation or positional relationship, which are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the indicated components or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0056] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "provided with", "connection" and the like should be understood in a broad sense, for example, "connection" can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be direct connection, can also be indirect connection through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0057] Embodiment one

[0058] Please refer to Figure 1 As shown in the drawings, the present application is a preparation method of a high-performance filling material of industrial solid waste, comprising the following steps:

[0059] S1. Raw material pretreatment

[0060] S11. Crushing and grading: the industrial solid waste powder is first crushed to a particle size of ≤2mm by a jaw crusher; the undersize (≤200μm) is collected for further grinding by using a vibrating screen.

[0061] S12. Ball milling subdivision: the classified powder is placed in a ball mill (or planetary ball mill), grinding medium is added to a loading rate of 50-60%, and wet milling is carried out at a speed of 50-80 r / min for 2-3 h to make the particle size distribution of the powder concentrate in 50-200 μm; after discharging, one-stage classification is performed using a cyclone classifier to remove particles <10 μm and >200 μm, and the uniformity of the product is ensured.

[0062] S13. Chemical purification: 100 parts of the ball-milled powder are added to 3 parts of a 0.5 mol / L dilute acid (such as H2SO4 or H3PO4) solution, and immersed in a stirring tank for 1-1.5 h to remove free alkali and soluble iron, calcium and other impurities in the powder; after the reaction is completed, the solid-liquid is separated by a continuous filter device, and the filter cake is repeatedly washed with circulating water until the pH of the filtrate is about 7; the obtained acid liquor and the washing waste liquor are collected to a waste liquor treatment system, and lime milk or sodium carbonate solution is added to adjust the pH to neutral, while promoting the formation of precipitates of heavy metal ions and suspended impurities; the precipitates (filter residues) are dewatered by pressure filtration and can be recycled as secondary resources or safely landfilled, and the supernatant after treatment can be partially reused as washing water to reduce emissions; the washed powder is dried in a belt dryer at 80-90°C for 3-4 h to obtain pretreated powder with a clean surface and low impurity content.

[0063] S2. Surface activation

[0064] S21. Alkali metal silicate coating: the pretreated powder is mixed with a 15% water glass (Na2SiO3) solution with a modulus of 2.5-3.3 in a certain proportion, and treated with an ultrasonic disperser for 30 min to improve the dispersion uniformity and break the passivation layer on the surface of the powder; then the mixed slurry is transferred to a high-pressure reaction kettle, and a hydrothermal reaction is carried out at 100-120°C (preferably 105-115°C) for 2.5-3.5 h to make the surface of the powder react with silicate and aluminate, and in-situ generate a dense and uniform Si-Al hydrothermal gel shell layer, thereby improving the interfacial activity and subsequent functionalization ability.

[0065] S22. Separation of activated product: after the hydrothermal reaction is naturally cooled to 25°C, the slurry is dewatered in a centrifuge (1500 rpm, 5 min) or a plate-and-frame filter press; the wet material is washed twice with deionized water at a ratio of 3 times the slurry, until the pH of the washing liquid is 6.8-7.2; after the moisture content of the wet material is reduced to <30%, it is sent to a fluidized bed dryer (80°C, 3 h) to obtain surface-activated microspheres; after drying, the material is subjected to mild screening or air classification according to the particle size requirements to ensure the uniformity of the product particle size and the efficiency of the subsequent modification reaction.

[0066] S3. Composite modification

[0067] S31. Introduction of nano additives

[0068] a. GO pre-dispersion: The nano-graphene oxide (GO) powder was first mixed with equal volume of deionized water at 0.8-1.5 wt% of the total microsphere mass, and then ultrasonically dispersed (power 200 W, frequency 20 kHz) for 10 min to break the agglomeration of GO sheets.

[0069] b. pH adjustment and interfacial activation: The pH of the GO dispersion was adjusted to 9-10 (with 0.1 mol / L NaOH) to load more carboxyl groups on the GO surface, enhancing the electrostatic adsorption to the surface of the hydrothermally activated microspheres.

[0070] c. Mixed adsorption: The GO dispersion was slowly dropped into a magnetic stirring tank containing the surface-activated microspheres at room temperature (25 ± 2 °C) (stirring rate 300 rpm), and stirring was continued for 1 h; samples were taken at regular intervals (every 15 min) during stirring, and the concentration of GO in the solution was determined by UV-visible absorbance or TOC to ensure uniform adsorption of GO to the microsphere surface; after stirring was complete, low-speed centrifugation (3000 rpm, 5 min) was used for separation, and the supernatant was discarded and the GO-microsphere complex was retained; a light wash (weak alkaline water at pH ≈ 9) was performed once to remove unadsorbed free GO while maintaining the integrity of the adsorption layer.

[0071] S32. Multifunctional carrier grafting

[0072] a. Biomass charcoal / phase change capsule pretreatment: Biomass charcoal powder was mixed with 3 wt% (based on the mass of GO-microsphere) and 0.5 wt% acryloxy silane coupling agent (AEAPTMS) solution, stirred at room temperature for 30 min, and dried to improve its surface hydrophilicity; or the phase change microcapsules were preheated in a 70 °C oven for 30 min to slightly soften the surface shell, facilitating subsequent grafting.

[0073] b. Synergistic grafting: The treated biomass charcoal powder or phase change microcapsules were added to the above GO-microsphere at once, and the stirring rate was increased to 400 rpm, and stirring was continued for 30 min.

[0074] S33. Drying and shaping: The uniformly stirred composite slurry was transported to a spray drying tower, and the inlet temperature was set to 150 ± 5 °C, the outlet temperature to 75 ± 5 °C, and the atomization pressure to 0.3-0.5 MPa to prepare a multifunctional composite powder with uniform particles; or the slurry was continuously dried in a hot air circulating drying oven (inlet temperature 120 °C, air speed 2 m / s), and the drying time was controlled to be 4-6 h, and the final product had a water content of <1%.

[0075] S4. Shaping and solidification

[0076] S41. Ingredient preparation and stirring

[0077] a. Carbonaceous material pretreatment: The biomass char was pre-coated with 0.5wt% silane coupling agent solution at 1-3wt% of the total composite powder, and dried after 30min of room temperature standing, to form a silane-Si-O-C bonding layer on the carbon surface, enhancing its chemical bonding with the cement matrix.

[0078] b. Stepwise batching: Stage A: Ordinary Portland cement (80 parts) was first mixed with 0.5wt% polycarboxylate superplasticizer, and water was added to a water-binder ratio of 0.30, and stirred for 2min to prepare a high-viscosity active slurry; Stage B: The silane-coupled carbonaceous material (20 parts) and 0.3wt% nano-SiO2 were stirred at low speed (300rpm) for 2min to ensure the carbonaceous material was well dispersed and formed a good wetting interface with the nano-SiO2 and superplasticizer in the slurry; the remaining amount of water was added to the Stage B product to a water-binder ratio of 0.35-0.50, and the total stirring time was controlled to be 3-5min; no vacuum degassing was required throughout the process, and only a vibration table (50Hz, 1min) was used to eliminate large air bubbles; if rapid forming was required, 2-5wt% of calcium sulfoaluminate (CSA) or silica fume could be additionally incorporated into the batching to promote early hydration heat release and setting, making up for the retardation effect caused by the carbonaceous material.

[0079] S42. Mold forming: The prepared homogeneous slurry was quickly poured into a standard test specimen mold (40mmx40mmx160mm) that had been degreased and sprayed with an anti-sticking agent (such as silicone oil); a vibration table (frequency 50-60Hz, amplitude 0.5-1.0mm) was used to vibrate for 1-2min, while a vacuum degassing device (vacuum-0.08MPa) was turned on for 30s to ensure that the slurry was dense and free of visible air bubbles; a polyethylene film or wet canvas was laid on the surface of the test specimen to prevent the surface moisture from evaporating too quickly; the mold was placed in a constant temperature and humidity box (20±2℃, relative humidity >90%) for curing for 24h, until the test specimen surface lost its tackiness and had sufficient strength to be demolded.

[0080] S43. Standard curing: After curing for 24h, the test specimen was removed using a demolding device by gently pushing or knocking the bottom of the test specimen; the demolded test specimen was placed on a curing plate and placed in a standard curing room (20±1℃, relative humidity 95±2%); the appearance of the test specimen was inspected and recorded for cracks, discoloration, etc. at 7d and 14d of curing;

[0081] By the 28th day of curing, the test specimen was removed for the following tests:

[0082] Mechanical properties: compressive strength, flexural strength;

[0083] Durability: compressive strength retention rate after freeze-thaw cycles (–20℃-20℃, 10 times);

[0084] Functionality: thermal conductivity test, sound absorption coefficient determination, and CO2 adsorption capacity analysis.

[0085] Embodiment Two

[0086] The embodiment is a process equipment and connection relationship for a preparation method of an industrial solid waste high-performance filling material.

[0087] Crushing and screening system: jaw crusher → vibrating screen, physical connection;

[0088] Ball milling and classification system: ball mill → air separator;

[0089] Chemical treatment device: acid leaching tank (equipped with stirrer, pH online monitoring) → solid-liquid separation filter;

[0090] Hydrothermal activation device: ultrasonic disperser → high-pressure reaction kettle (with temperature control and safety valve) → vacuum filter;

[0091] Composite drying system: magnetic stirring tank → spray drying tower (or hot air drying oven);

[0092] Molding and curing system: manifold stirrer → jolting table → curing chamber;

[0093] Each unit equipment is connected with pipes, pumps, valves and control systems to realize automatic or semi-automatic production of raw materials, intermediates and finished products.

[0094] Through the above technical scheme, the industrial solid waste is deeply activated and multifunctionally modified while ensuring the simplicity and scalability of the preparation process, and the prepared filling material is significantly improved in mechanical properties, durability, heat insulation, sound absorption and carbon capture, thereby meeting the dual needs of modern engineering construction and environmental protection.

[0095] It should be further explained that the present application solves the defects of poor interface bonding, single function and complex process of the existing solid waste filling material through surface activation gel coating, nano-multifunctional synergistic modification and optimized molding and curing, and achieves the following main beneficial effects (arranged from high to low in importance):

[0096] 1. Significantly improving mechanical properties and interface bonding strength

[0097] Effect performance: the 28d compressive strength of the test piece is increased by ≥15% compared with the control group, and the crack ductility is significantly improved; the interface peeling energy (mode II interface fracture energy) is increased by >25%.

[0098] Technical source: in step S21, the Na2SiO3-hydrothermal reaction generates a 0.5-2 μm thick Si-Al gel coating layer in situ, breaks the surface passivation layer and introduces a large number of Si-O-Al chemical bonding sites, and at the same time realizes micro occlusion.

[0099] 2. Multifunctional performance

[0100] Effect performance:

[0101] Thermal insulation: overall thermal conductivity reduced by 20–30%;

[0102] Sound absorption: composite sound absorption coefficient up to 0.5–0.7;

[0103] Carbon capture: CO2 adsorption capacity reaches 0.5–1.2 mmol / g.

[0104] Technical source: In step S32, GO improves thermal conductivity regulation and crack resistance, and biomass charcoal / phase change capsule forms hierarchical pores, realizing the synergistic effect of heat management, sound energy dissipation and gas adsorption.

[0105] 3. Process simplification, cost control

[0106] Effect performance: Compared with traditional alkali activation or high-temperature calcination process, ≥2 steps are reduced; without high alkali concentration and long curing, after optimization of raw material and chemical agent dosage, the unit material cost is reduced by about 10–20%.

[0107] Technical source: The combination of acid leaching purification and hydrothermal activation completes the surface activation in one step; the combination of multifunctional modification and drying spray process saves an additional modification step and separation process.

[0108] 4. Improve durability and long-term stability

[0109] Effect performance: After standard freeze-thaw cycle (–20℃-20℃, 25 times), the compressive strength retention rate is >90%; the carbonation depth is reduced by about 30% compared with the control.

[0110] Technical source: The dense protective layer constructed by Si-Al gel and GO double coating reduces the erosion of alkali calcium silicate phase and freeze-thaw damage; the pore structure of biomass charcoal buffers the change of internal stress.

[0111] 5. Controllable micro / multilayer structure

[0112] Effect performance: The porosity of the material can be precisely adjusted to 15–25%, and the pore size distribution presents a three-level structure of micropores (<2 nm), mesopores (2–50 nm) and macropores (>50 nm), meeting different mechanical and functional requirements.

[0113] Technical source: By adjusting the amount of biomass charcoal or phase change capsule and the spray drying parameters (inlet temperature, outlet temperature, atomization pressure), the controllable design of multi-level pore structure is realized.

[0114] Example Three

[0115] This example is an alternative in the preparation method of industrial solid waste high-performance filling material:

[0116] S1. Raw material pretreatment alternatives

[0117] S11. Crushing and classification

[0118] Primary crushing can be replaced by hammer crusher or impact crusher instead of jaw crusher;

[0119] Classification can be replaced by cyclone classifier instead of vibrating screen, and the particle size range of undersize can be adjusted to ≤150 μm or ≤250 μm to meet different application requirements.

[0120] S12. Ball milling subdivision

[0121] Ball mill can be replaced by rod mill or planetary ball mill, and the grinding time can be changed to 1-3 h;

[0122] Air classification can be replaced by air separation or hydraulic separation to remove ultra-fine particles (<5 μm) and coarse particles (>220 μm).

[0123] S13. Chemical purification

[0124] Acid leaching purification can be replaced by 0.3-1.0 mol / L citric acid or acetic acid instead of dilute H2SO4 / H3PO4;

[0125] 0.1-0.5 mol / L NaOH solution can also be used for alkaline cleaning to remove free metal ions and alkaline impurities;

[0126] The drying conditions can be natural drying at 80-120 ℃ or vacuum low-temperature drying.

[0127] S2. Surface activation alternatives

[0128] S21. Alkali metal silicate coating

[0129] Water glass solution can be replaced by 10-20 wt% K2SiO3 solution;

[0130] Ultrasonic assistance can be omitted and replaced by mechanical high-speed shear dispersion for 30-60 min;

[0131] The hydrothermal reaction temperature can be adjusted in the range of 80-140 ℃, and the reaction time can be shortened to 1-3 h.

[0132] S22. Separation of activated products

[0133] Vacuum filtration can be replaced by centrifugal separation (3000-5000 rpm, 5-10 min);

[0134] Washing can use online circulating washing method to save water consumption;

[0135] Drying can be replaced by freeze-drying or microwave drying to improve the retention of pore structure.

[0136] S3. Composite modification alternatives

[0137] S31. Nano-additive introduction

[0138] Nano-graphene oxide (GO) can be replaced by nano-silica (SiO2-NP), nano-alumina (Al2O3-NP), or carbon nanotubes (CNT) with an addition amount ranging from 0.2 to 3 wt%;

[0139] The dispersion method can be replaced by high-speed homogenization or microemulsification.

[0140] S32. Multi-functional carrier grafting

[0141] Biomass charcoal can be replaced by foam glass, vermiculite, or mullite microspheres;

[0142] Phase change microcapsules can be replaced by paraffin phase change materials, polyvinyl alcohol phase change capsules, or chitosan-based phase change capsules;

[0143] S33. Drying methods can be vacuum spray drying or fluidized bed drying.

[0144] S4. Forming and curing alternatives

[0145] S41. Ingredient mixing and stirring

[0146] The composite powder to cement ratio can be adjusted to 10:90 to 30:70 to accommodate different strength requirements;

[0147] The water-binder ratio can be extended to 0.30-0.55, or a polycarboxylic acid water reducer can be introduced to reduce the water-binder ratio;

[0148] Stirring can be done using high-shear stirring or vacuum degassing stirring.

[0149] S42. Mold forming

[0150] Standard test specimen molds can be replaced by plate, pipe, or special-shaped molds, or extrusion molding processes can be used;

[0151] The initial curing can be done in a 60-80℃ oven with steam curing for 1-2 days to accelerate hydration;

[0152] S43. Standard curing

[0153] Standard curing conditions can be changed to 65℃ saturated steam curing or salt water mist curing;

[0154] Long-term outdoor curing (6-12 months) under natural conditions can also be used to test long-term durability.

[0155] In the description of the specification, reference to "one embodiment", "an example", "a specific example" or the like means that a particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. The appearances of the phrases "in one embodiment", "an example", "a specific example" or the like in various places in the specification are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0156] The preferred embodiments of the application disclosed above are only to help explain the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the contents of the specification. The specification selects and specifically describes these embodiments in order to better explain the principles and practical application of the application, so that those skilled in the art can well understand and utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an industrial solid waste high-performance filler material, characterized in that, The method comprises the following steps: S1, raw material pretreatment: S11, crushing the industrial solid waste powder to a particle size of ≤2 mm, and grading through a vibrating screen, collecting the powder ≤200 μm for ball milling; S12, adding grinding media to the ball mill to a loading rate of 50-60%, wet milling at a speed of 50-80 r / min for 2-3 h to obtain a powder with a particle size distribution concentrated in 50-200 μm; S13, chemically purifying the powder after ball milling to remove free alkali and soluble impurities, and drying to obtain a pretreated powder. S2, surface activation: S21, mixing the pretreated powder with a water glass solution, treating with an ultrasonic disperser, and then performing a hydrothermal reaction to generate a Si-Al hydrothermal gel shell; S22, separating, washing and drying the hydrothermal reaction product to obtain surface-activated microspheres. S3, composite modification: S31, dispersing and adsorbing nano-graphene oxide (GO) on the surface of the surface-activated microspheres; S32, synergistically grafting biomass charcoal or phase change microcapsules with GO-microspheres to form a composite slurry; S33, drying and forming the composite slurry to obtain a multifunctional composite powder. S4, molding and curing: S41, mixing and stirring the composite powder with ordinary Portland cement, carbonaceous material, nano-SiO2 and water reducing agent to form a homogeneous slurry; S42, pouring the homogeneous slurry into a mold, and performing vibration defoaming, film coating and moisture retention and initial curing; S43, standard curing the preliminarily cured test piece to obtain a final product.

2. The method for preparing an industrial solid waste high-performance filling material according to claim 1, characterized in that, In the step S1, the powder after ball milling is removed of impurities by acid immersion and continuous filtration, and the filtrate pH is adjusted to neutral, and the precipitate is dewatered by pressure filtration and recycled as a secondary resource or safely landfilled.

3. The method for preparing a high-performance filling material for industrial solid waste according to claim 1, characterized in that, In the step S2, the hydrothermal reaction is performed at 100-120℃ for 2.5-3.5 h, and the activated product is centrifuged, washed and fluidized bed dried to obtain surface-activated microspheres.

4. The method for preparing a high-performance filling material for industrial solid waste according to claim 1, characterized in that, In the step S3, GO is adsorbed on the surface of the microspheres after ultrasonic dispersion and pH adjustment, and biomass charcoal or phase change microcapsules are synergistically grafted with GO-microspheres after pretreatment, and multifunctional composite powder is obtained by spray drying or hot air circulation drying.

5. The method for preparing a high-performance filling material for industrial solid waste according to claim 1, characterized in that, In the step S4, a staged batching method is used in the batching process, a high-viscosity active slurry is first prepared, carbonaceous material and nano-SiO2 are then added for low-speed stirring, and the balance of water is finally added to adjust the water-binder ratio, and air bubbles are eliminated by a vibration table; after molding, the test piece is cured in a constant temperature and humidity box for 24 h, and tested in a standard curing room until the 28th day.

6. An industrial solid waste high-performance filling material prepared by the preparation method of any one of claims 1 to 5.

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