Coal-based multi-element solid waste artificial lightweight aggregate as well as preparation method and application thereof

Abstract

The invention discloses a coal-based multi-component solid waste artificial lightweight aggregate and a preparation method and application thereof, and belongs to the technical field of solid waste resource utilization, the preparation method comprises the following steps: selecting natural gravel coarse aggregate particles, and grading to form a coarse aggregate set; cleaning the coarse aggregate set, immersing the coarse aggregate set in a silica gel mixed solution, and after the silica gel mixed solution is cured, taking out natural gravel coarse aggregate particles to obtain a turnover mold for preparing the aggregate; adding fly ash, cement and basalt fiber into the crushed coal gangue; adding a mixture of a water reducing agent and water, and uniformly mixing and stirring to obtain a pretreated material; pouring the pretreated material into a rollover mold, and demolding to obtain the artificial lightweight aggregate; finally, the coal-based multi-element solid waste artificial lightweight aggregate is obtained. The shape and grain composition of the coarse aggregate are accurately controlled through a self-made rollover mold, and the basalt fibers are bonded to the surface of the artificial lightweight aggregate in an adhesion interface transition area, so that the problems of low substitution rate, high discreteness, brittle failure and the like of the coal gangue as the concrete coarse aggregate can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of new building materials and solid waste resource utilization, and particularly relates to a coal-based multi-solid waste artificial lightweight aggregate, a preparation method thereof, and an application thereof. Background Art

[0002] The speed and scale of the renewal and construction of construction projects are unprecedented, and the demand for sand and gravel aggregates increases year by year. Quarrying and sand digging have seriously damaged the ecological environment. To solve this prominent contradiction between large-scale construction and environmental protection, it is urgent to develop corresponding alternative "artificial aggregates". As one of the solid wastes with the largest emissions, the comprehensive utilization rate of coal gangue is less than 60%. A large amount of stockpiling not only occupies land resources, but also pollutes the environment, damages vegetation, and triggers geological disasters such as collapses, landslides, and debris flows. Facing the current situation of high-output and high-risk coal gangue stockpiling, how to turn waste into treasure, reduce environmental pollution, and realize the transformation from "mainly stockpiling" to "mainly utilization" has become one of the social problems that scientific workers urgently need to solve.

[0003] At present, coal gangue is mainly used as a building material: (1) Crushing coal gangue directly as coarse aggregate for preparing concrete can effectively solve the problem of coal gangue stacking, reduce environmental pollution, and alleviate the shortage of natural sand and gravel resources. However, the strength of coal gangue in different regions, different rock layers, and different structures has large discreteness. After crushing, the coal gangue shows characteristics of high cracks, high water absorption, and high dust. The strength of coal gangue concrete has strong randomness and discreteness, and is relatively brittle, prone to cracking, which limits its application in engineering. (2) Using coal gangue to replace clay to prepare sintered ceramsite by high-temperature roasting can consume a large amount of stockpiled coal gangue and reduce the cost of building materials. However, the production process has disadvantages such as high energy consumption, high cost, and complicated roasting process, which is not conducive to the transformation to an energy-saving and emission-reducing green industry, and is even more contrary to the development concept of the global low-carbon circular economy. Therefore, there is an urgent need for a method to eliminate the discreteness of coal gangue and prepare concrete and cement-related products with characteristics such as low-carbon environmental protection.

[0004] The preparation of artificial aggregates by cold bonding granulation technology first involves agglomerating powdery or muddy waste into pellets of the required size, and then through curing processes (such as sintering, water curing, wet curing, and carbonation), the artificial lightweight aggregate pellets generate a certain strength. The cold bonding granulation process is mainly divided into two categories: the extrusion molding process and the stirring granulation process. It mainly processes powdery materials into lump materials that meet specific shapes, compositions, densities, etc. through specific equipment and methods. Most of the existing cold bonding granulation technology aggregates are circular or nearly spherical in shape, and there are several problems with spherical aggregates in terms of concrete strength and durability. For example: spherical aggregates are prone to stress concentration when stressed, resulting in local cracking and relatively low compressive strength; spherical aggregates are more likely to break when subjected to impact and extrusion, have higher abrasion, and poorer stability; spherical aggregates have weak frost resistance and fatigue resistance, and are prone to microcrack accumulation under repeated loading conditions, leading to material failure; the interfacial transition zone between spherical aggregates and mortar is relatively weak. Based on the cold bonding technology, the preparation of artificial coarse aggregates has a certain feasibility, but its particle shape is relatively single, the gradation is poor, the interfacial bonding ability with mortar is weak, the preparation process is relatively complex, and there is no report on the preparation of coal-based solid waste artificial aggregates using cold bonding technology. Therefore, it is necessary to improve the cold bonding granulation technology for the preparation of lightweight artificial aggregates from coal-based solid waste. Summary of the Invention

[0005] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a coal-based multi-solid waste artificial lightweight aggregate, its preparation method and application. By efficiently utilizing coal gangue, artificial lightweight aggregates with controllable particle size and shape and basalt fiber filaments attached to the surface at the interfacial transition zone are prepared, thereby reducing raw material costs, saving energy, and reducing carbon emissions, and comprehensively improving the resource utilization efficiency of coal gangue.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: In the first aspect, the present invention provides a preparation method for coal-based multi-solid waste artificial lightweight aggregates, including the following steps: Select natural crushed stone coarse aggregate particles and perform gradation to form a coarse aggregate set; After cleaning the coarse aggregate set, immerse it in a silica gel mixture. After the silica gel mixture cures, take out the natural crushed stone coarse aggregate particles to obtain a mold for preparing aggregates; Add fly ash, cement, and basalt fiber to the crushed coal gangue; then add a mixture of water reducer and water, and mix and stir evenly to obtain a pretreated material; the mass ratio of the coal gangue, fly ash, cement, basalt fiber, water reducer, and water is (3.3~4.2):(4.6~6.2):(1.0~5.2):(0.1~0.2):(0.01~0.02):(3.6~3.8); Pour the pre-treated material into the mold, and after natural curing for the first time, demold it after the pre-treated material solidifies to obtain artificial lightweight aggregate; after the artificial lightweight aggregate is naturally cured for the second time, the finished product of coal-based multi-solid waste artificial lightweight aggregate is obtained.

[0007] As a further improvement of the present invention, the coarse aggregate is composed of natural crushed stone coarse aggregate particles with particle sizes of 10-15 mm, 15-20 mm, and 20-30 mm mixed together.

[0008] As a further improvement of the present invention, the shape coefficient of the natural crushed stone coarse aggregate particles is 0.65-0.95.

[0009] As a further improvement of the present invention, the conditions for curing the silica gel mixture are natural drying at 15-25 °C for 3-5 h.

[0010] As a further improvement of the present invention, the particle size of the coal gangue is below 0.9 mm.

[0011] As a further improvement of the present invention, it further includes slag and waste glass; The mass ratio of the coal gangue to the slag and waste glass is (3.3-4.2):(4.0-5.7):(0.42-4.2).

[0012] As a further improvement of the present invention, the time for the first natural curing is 3 days; the time for the second natural curing is 28 days.

[0013] In the second aspect, the present invention provides a coal-based multi-solid waste artificial lightweight aggregate prepared by using the preparation method of the coal-based multi-solid waste artificial lightweight aggregate described above.

[0014] Preferably, the water absorption rate of the coal-based multi-solid waste artificial lightweight aggregate is 7.19%-11.56%; the apparent density is 1789.37-2047.23 kg / cm 3 ; the bulk density is 793.11-848.36 kg / cm 3 ; the crushing value index is 9.27%-15.18%.

[0015] In the third aspect, the present invention provides an application of the coal-based multi-solid waste artificial lightweight aggregate prepared by using the preparation method of the coal-based multi-solid waste artificial lightweight aggregate described above in the preparation of building materials.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a preparation method of coal-based multi-solid waste artificial lightweight aggregate. Coal gangue particles, fly ash and other multi-solid wastes are used to prepare artificial lightweight aggregate with controllable particle size and shape, and basalt fibers are added to make basalt fiber filaments attached to the surface of the aggregate to form an interfacial transition zone. Specifically: First, the coal gangue particles after crushing eliminate defects such as most of the pores and fissures in the original coal gangue, effectively realizing the synergistic effect of multi-coal-based solid wastes, eliminating the gaps between different particles, enhancing the compactness of the artificial aggregate, and effectively improving the physical and mechanical property indexes and forming effect of the aggregate. Second, the prepared silica gel material can effectively intervene and optimize the particle size and shape of the coarse aggregate, accurately adjust the grading distribution of the coarse aggregate, improve the bulk density of the coarse aggregate, and then enhance the compaction value index of the coarse aggregate, effectively improving the physical and mechanical properties of the concrete. Third, basalt fibers have a high elastic modulus, good compatibility with silicate and a thermal expansion coefficient similar to that of concrete. Adding basalt fibers to the artificial aggregate can not only effectively improve the toughness of the aggregate itself, but also the basalt fiber filaments attached to its surface can form a network structure in the mortar interfacial transition zone, enhancing the mechanical properties and durability of the concrete.

[0017] The present invention is a new way of resource utilization of coal gangue, having an absolute advantage in carbon reduction and carbon utilization. These advantages make it have a wide application prospect in construction and infrastructure construction. This method effectively reduces the large amount of cement used in the traditional formula, thus reducing the raw material cost and avoiding the indirect carbon emissions caused by the use of cement. Through a self-made mold, the particle size and shape of the coal-based multi-solid waste artificial lightweight aggregate can be accurately controlled. In addition, the required equipment is simple, the preparation process does not require high-temperature calcination, saving energy, and the required materials are easy to obtain, achieving the goal of low raw material cost, low operation cost and low construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of preparing coal-based multi-solid waste artificial lightweight aggregate by the mold used in the present invention; Figure 2 It is a flow chart of preparing coal-based multi-solid waste artificial lightweight aggregate disclosed by the present invention; Figure 3 It is a graph of the bulk density results of all examples of the present invention; Figure 4 It is a graph of the apparent density results of all examples of the present invention; Figure 5 It is a graph of the water absorption results of all examples of the present invention; Figure 6 It is a graph of the crushing value index results of all examples of the present invention; Figure 7SEM (Scanning Electron Microscope) test diagram of the coal-based multi-solid waste artificial lightweight aggregate disclosed in Embodiment 5 of the present invention; among them, (a) and (b) are schematic diagrams of hydration products in the coal-based multi-solid waste artificial lightweight aggregate. Figure 8 SEM test diagram of the coal-based multi-solid waste artificial lightweight aggregate disclosed in Embodiment 6 of the present invention; among them, (a) is an internal view of the artificial lightweight aggregate magnified by 5 ; (b) is an internal view of the artificial lightweight aggregate magnified by 20 . Figure 9 SEM test diagram of the coal-based multi-solid waste artificial lightweight aggregate disclosed in Embodiment 5 of the present invention; among them, (a) is a schematic diagram of basalt fibers and the nearby hydrated substances inside the artificial lightweight aggregate magnified by 20 ; (b) is the distribution of basalt fibers magnified by 100 . Figure 10 XRD (X-Ray Diffraction) diagrams of the coal-based multi-solid waste artificial lightweight aggregate disclosed in Embodiments 5, 6, and 7 of the present invention. Figure 11 Schematic diagram of the compressive strength results of cubic concrete specimens. Figure 12 Schematic diagram of the compressive failure of cubic concrete specimens in the present invention, where (a) is the schematic diagram of the compressive failure of M0 cubic concrete specimens; (b) is the schematic diagram of the compressive failure of M5 cubic concrete specimens. Detailed implementation manners

[0019] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] In the present invention, if there is no special explanation, all the implementation manners and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0021] In the present invention, if there is no special explanation, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0022] In the present invention, if there is no special explanation, the percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0023] In the present invention, unless otherwise specified, the various components involved or their preferred components can be combined with each other to form a new technical solution.

[0024] In the present invention, unless otherwise stated, the numerical range "a~b" represents an abbreviated representation of any real number combination between a and b, where both a and b are real numbers. For example, the numerical range "6~22" means that all real numbers between "6~22" have been fully listed herein, and "6~22" is only an abbreviated representation of these numerical combinations.

[0025] The "range" disclosed in the present invention can be in the form of one or more lower limits and one or more upper limits, respectively.

[0026] In the present invention, the term "and / or" used herein refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0027] In the present invention, unless otherwise specified, each reaction or operation step can be carried out sequentially or in order. Preferably, the reaction method herein is carried out sequentially.

[0028] Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to persons skilled in the art. In addition, any method or material similar or equivalent to the described content can also be applied to the present invention.

[0029] Aiming at the problems of high discreteness of material properties, low strength, large randomness, brittle failure, high energy consumption and high cost of traditional utilization methods when coal gangue is directly used as raw materials for concrete and cement products, based on the existing cold bonding granulation technology, it is urgent to propose a new coal-based multi-solid waste artificial lightweight aggregate and its preparation method, preparing an artificial lightweight aggregate with a high substitution rate of coal-based solid waste, controllable particle size and shape, and basalt fiber filaments attached to the surface at the interface transition zone, so as to realize the efficient, environmental protection and resource utilization of coal gangue.

[0030] The coal-based multi-solid waste artificial lightweight aggregate prepared by the method of the present invention is a multi-angular artificial coarse aggregate similar to natural crushed stone coarse aggregate particles, with high compressive strength, mainly because its edges and corners can disperse the stress more evenly, reducing the risk of local fracture, and the surface is rough, which can form a stronger bonding force with cement-based materials. Through its structural advantages, it not only improves the strength and durability of concrete, but also enhances its adaptability, making it an ideal choice for engineering projects with high strength and durability requirements.

[0031] In the first aspect, optimize the filling shape of the turning mold and the aggregate particle size of the coal-based multi-solid waste artificial lightweight aggregate: Aggregates are the fillers with the largest volume proportion in concrete. They have relatively high strength and play a role of skeleton support in the overall structure. Aggregates significantly affect the workability of concrete and the interfacial transition zone between the aggregates and the cementitious materials.

[0032] First, randomly select 8000 g of natural crushed stone coarse aggregate particles, wash and dry them. Due to the complexity and difficulty of measuring the shape of natural crushed stone coarse aggregate particles, in this invention, the natural crushed stone coarse aggregate particles are evaluated through the shape coefficient parameter, and the natural crushed stone coarse aggregate particles with the measured shape coefficient value close to 0.65 - 0.95 are preferably selected through artificial intervention.

[0033] Select the preferred coarse aggregates with particle sizes between 10 - 15 mm, 15 - 20 mm, and 20 - 30 mm by sieving method for standby. After washing and drying, they are re - mixed in different proportions as shown in Table 1.

[0034] Table 1. Particle size distribution parameters of natural crushed stone coarse aggregates with different particle sizes

[0035] According to the test method standard (JGJ 52 - 2006), the crushing value index tests are carried out on the coarse aggregates with different gradations in Table 1, and the results are shown in Table 2.

[0036] Table 2. Crushing value index of each gradation

[0037] It can be seen from Table 2 that when the mass percentage of the coarse aggregates with particle sizes of 10 - 15 mm in gradation 3 is 5%, the mass percentage of the coarse aggregates with particle sizes of 15 - 20 mm is 15%, and the mass percentage of the coarse aggregates with particle sizes of 20 - 30 mm is 80%, the crushing value index is the best, which improves the overall performance. The natural crushed stone coarse aggregate particles of gradation 3 are used as the filler of the mold - turning mold.

[0038] See Figure 1 for the schematic diagram of the preparation of the mold - turning mold adopted in this invention; it can be seen from Figure 1 that the preparation method of the mold - turning mold includes: First, silicone A of model GH - 636 and silicone B are strictly mixed at a mass ratio of 1:1, poured into a container, and stirred for about 5 min until completely mixed evenly and there are no bubbles on the surface, obtaining a silicone mixed solution; Among them, both silicone A and silicone B are liquid silicones, which belong to the prior art and are briefly described as follows: GH~636 silicone A and silicone B are two-component addition-curing liquid silicones, which are used by mixing in a weight ratio of 1:1. They have characteristics such as low shrinkage rate, high temperature resistance (300~500 °C), and rapid curing (30 minutes of operation at room temperature and 2~3 hours of complete curing); two-component system: composed of component A (containing platinum-based catalyst) and component B (containing methylhydrogensiloxane crosslinking agent and alcohol inhibitor), and need to be used by mixing in a weight ratio of 1:1. Crosslinking and curing are carried out through hydrosilylation reaction. After mixing, the inhibitor controls the reaction rate to ensure that the operation time is controllable. Curing conditions: The operation time is 30 minutes at 28 °C for room temperature curing, and it is completely cured in 2~3 hours. Heating acceleration: The curing time is shortened to dozens of minutes at 60~120 °C.

[0039] Arrange the natural crushed stone coarse aggregate of grading 3 in Table 2 neatly in the container in sequence. Inject the silicone mixture into the container in batches. Pour a thin layer sufficient to cover the bottom for the first time, and adjust the natural crushed stone coarse aggregate particles with deviated positions. Slowly inject the silicone mixture for the second time until the natural crushed stone coarse aggregate particles are covered to about two-thirds of the position, and adjust the natural crushed stone coarse aggregate particles with deviated positions again; finally pour enough silicone mixture to make it about 5 mm higher than the surface of all natural crushed stone coarse aggregate particles to ensure that all natural crushed stone coarse aggregate particles are completely wrapped. Finally, place the container in a natural drying environment at room temperature (20 °C ± 5 °C) for more than 3 hours until the surface of the silicone is no longer sticky and smooth, and then the mold of the silicone material can be taken out of the container and the natural crushed stone coarse aggregate particles can be taken out to complete the production of the final mold.

[0040] In the second aspect, preparing coal-based multi-solid waste artificial lightweight aggregate includes raw materials with the following masses: 1.0~5.2 kg of cement, 3.3~4.2 kg of fly ash, 0.1~0.2 kg of basalt fiber, 0.42~4.2 kg of waste glass, 3.6~3.8 kg of water, 3.3~4.2 kg of coal gangue, 4.0~5.7 kg of slag, 0.01~0.02 kg of water reducing agent, and adjust appropriately according to the actual situation.

[0041] Table 3. Technical parameters of main raw materials for preparing coal-based multi-solid waste artificial lightweight aggregate

[0042] See Table 3 for the technical parameters of raw materials for preparing coal-based multi-solid waste artificial lightweight aggregate; it can be seen from Table 3 the basic introduction of relevant raw materials.

[0043] Table 4. Mass ratio of each material per cubic meter of coal-based multi-solid waste artificial lightweight aggregate

[0044] See Table 4 for the mass ratio of each material in per cubic meter of coal-based multi-solid waste artificial lightweight aggregate; it can be seen from Table 4 the mass ratio of each material for making coal-based multi-solid waste artificial lightweight aggregate.

[0045] The core principle of the present invention is as follows: Through artificial intervention, natural crushed stone coarse aggregate particles with a shape particle shape coefficient of 0.65 - 0.95 are preferably selected, and the particle gradation of the preferably selected natural crushed stone coarse aggregate particles is optimized to form a coarse aggregate set; After the coarse aggregate set with optimized gradation is pretreated (washed and dried), it is immersed in a silica gel mixture. After the silica gel mixture is cured, the natural crushed stone coarse aggregate particles are taken out to obtain a mold for preparing aggregates; To the crushed coal gangue, slag, fly ash, cement, waste glass, and basalt fiber are added; then a mixture of water reducing agent and water is added, and they are mixed and stirred evenly to obtain a pretreatment material, namely the inverted mold granulation method; The pretreatment material is poured into the mold, and after one natural curing, the artificial lightweight aggregate is demolded after the pretreatment material solidifies; after the artificial lightweight aggregate is subjected to secondary natural curing, the finished product of coal-based multi-solid waste artificial lightweight aggregate is obtained.

[0046] The present invention, through a self-made mold and combined with the inverted mold granulation method, precisely controls the shape and particle gradation of the coarse aggregate, and improves problems such as low substitution rate, high discreteness, and brittle failure of coal gangue as a concrete coarse aggregate. It prepares artificial lightweight aggregate with a high substitution rate of coal-based solid waste, controllable particle size and shape, and basalt fiber filaments attached to the surface at the interfacial transition zone, effectively achieving the low-carbon and environmental protection goals of the resource utilization of coal gangue. Adding slag, fly ash, cement, waste glass, and basalt fiber to coal gangue can form a cementitious system with a synergistic effect to jointly improve the material properties. Cement provides an alkaline environment and hydrates to generate a large amount of C-S-H by itself, which is the main source of strength; slag reacts quickly in the early stage to increase the initial strength; fly ash participates in the later reaction to optimize the structure; waste glass has high activity and also has a filling effect; basalt fiber enhances crack resistance and toughness, and at the same time enhances the interfacial transition zone. Multiple materials complement and cooperate with each other to improve strength, density, and durability, making up for the deficiency of low activity of coal gangue.

[0047] In addition, basalt fiber is a high-performance inorganic basalt fiber made by melting and drawing basalt ore, with characteristics such as high strength, high modulus, and corrosion resistance. In the cementitious system, basalt fibers are randomly distributed in the matrix, effectively restraining crack propagation and improving tensile strength and toughness. The synergistic effect between coal gangue and basalt fiber lies in that the pozzolanic reaction of coal gangue generates C-S-H gel, which, combined with the crack resistance effect of basalt fiber, significantly improves the compressive, tensile, and flexural strengths. The toughening effect of basalt fiber synergizes with the cementitious products of coal gangue, enabling the material to exhibit better deformation ability and energy absorption ability under stress. Coal gangue refines the pore structure, and basalt fiber reduces cracks. Together, they reduce the permeation channels and improve the resistance to chloride ion erosion and carbonation. The micro-aggregate effect of coal gangue synergizes with the "supporting" effect of basalt fiber to reduce segregation and bleeding and improve the fluidity of concrete. The restraint effect of basalt fiber combined with the expansion compensation effect of coal gangue reduces drying shrinkage and plastic shrinkage.

[0048] As Figure 1 and Figure 2 shown, the present invention provides a method for preparing coal-based multi-solid waste artificial lightweight aggregate, comprising the following steps; According to mass percentages, select 5% of coarse aggregate with a particle size of 10 - 15 mm, 15% of coarse aggregate with a particle size of 15 - 20 mm, and 80% of coarse aggregate with a particle size of 20 - 30 mm that have excellent performance, and perform compound admixture. Then, select plump natural crushed stone coarse aggregate particles with a polyhedral shape (the shape coefficient is 0.65 - 0.95), wash, dry, and evenly arrange them in container A for standby. Mix silica gel A of model GH - 636 and silica gel B strictly according to a mass ratio of 1:1, place them in container B, and use a stirrer to stir for 5 minutes until uniform.

[0049] Subsequently, pour the mixed silica gel mixture into container A containing natural crushed stone coarse aggregate particles to ensure that the natural crushed stone coarse aggregate particles are completely covered by the silica gel mixture. Let it stand for 3 h. After the silica gel mixture solidifies, take out the natural crushed stone coarse aggregate particles to obtain a mold for preparing the aggregate; repeat this step to obtain multiple molds for standby; Put coal gangue into a crusher for crushing and screening to obtain coal gangue particles with a particle size of less than 0.9 mm; weigh coal gangue, slag, fly ash, cement, waste glass, and basalt fiber according to the ratio; weigh a water reducer and water, stir the two evenly, pour them into the raw materials, and use a stirrer to stir. After uniform stirring, obtain a pretreated material; evenly pour the pretreated material into the mold. This operation should be placed on a vibrating table to ensure that it is filled plumply and smoothly, and placed in a flat, dry, and ventilated area. Cure for 3 d, and then demold after the pretreated material solidifies; put the demolded artificial lightweight aggregate into container C of the water-silica gel mixture, with the liquid covering the surface of the artificial lightweight aggregate, and cure for 28 d to obtain the finished product of coal-based multi-solid waste artificial coarse aggregate.

[0050] Figure 3 This is the preparation flow chart of the coal-based multi-solid waste artificial lightweight aggregate disclosed by the present invention; it can be seen from the figure that the preparation process includes: after weighing all raw materials, the water reducing agent and water are stirred and then poured into the raw materials for stirring, the slurry is filled into the mold, and after curing for 3 days and waiting for the slurry to solidify, the artificial lightweight aggregate particles are taken out and cured in water for 28 days (d refers to days).

[0051] 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 with reference to the accompanying drawings in the embodiments of the present invention.

[0052] Example 1 A coal-based multi-solid waste artificial lightweight aggregate, comprising raw materials with the following masses: 6.190 kg of fly ash, 5.158 kg of cement, 3.766 kg of water, 0.105 kg of basalt fiber, 4.127 kg of quartz sand and 0.01 kg of water reducing agent. Denote it as G1.

[0053] This embodiment also includes the preparation method of the coal-based multi-solid waste artificial lightweight aggregate, and the steps are as follows: Select natural crushed stone coarse aggregate particles with sizes of 10 - 15 mm, 15 - 20 mm and 20 - 30 mm, wash and dry them, and put them into container A for standby. Silicone A and silicone B of model GH - 636 are strictly mixed according to a mass ratio of 1:1, placed in container B, and stirred by a mixer for 5 minutes until uniform.

[0054] Subsequently, the mixed silicone liquid is poured into container A containing natural crushed stone coarse aggregate particles to ensure that the natural crushed stone coarse aggregate particles are completely covered by the silicone liquid. Let it stand for 3 hours, and after the silicone liquid cures, take out the natural crushed stone coarse aggregate particles to obtain the mold for preparing the aggregate; repeat this step to obtain multiple molds; Put coal gangue into a crusher for crushing and screening to obtain coal gangue particles with a particle size below 0.9 mm; weigh coal gangue, slag, fly ash, cement, quartz sand, waste glass and basalt fiber according to the ratio; Weigh the water reducing agent and water, stir the two evenly, pour them into the raw materials, and stir with a mixer. After uniform stirring, a pretreated material is obtained; Pour the pretreated material evenly into the mold. This operation should be placed on a vibrating table to ensure that it is filled evenly and smoothly. The mold filled with the pretreated material is placed in a flat, dry and ventilated place for curing for 3 days (days). After the pretreated material solidifies, demold to obtain the artificial lightweight aggregate; standing for 3 days can make the substances contact more fully; Collect the artificial lightweight aggregate, put it into container C, pour in water to cover the surface, and cure for 28 days to obtain the finished artificial lightweight aggregate.

[0055] Example 2 A coal-based multi-solid waste artificial lightweight aggregate, comprising raw materials with the following masses: 6.190 kg of fly ash, 5.158 kg of cement, 3.300 kg of coal gangue, 3.766 kg of water, 0.105 kg of basalt fiber, 0.830 kg of quartz sand, and 0.01 kg of water reducing agent. Denote it as G2.

[0056] This example also includes the preparation method of the coal-based multi-solid waste artificial lightweight aggregate, and the steps are as follows: Select natural crushed stone coarse aggregate particles of 10 - 15 mm, 15 - 20 mm, and 20 - 30 mm, wash and dry them, and put them into container A for standby. Mix silica gel A of model GH - 636 and silica gel B strictly according to a mass ratio of 1:1, place them in container B, and stir with a mixer for 5 minutes until uniform.

[0057] Use the mold obtained in Example 1; Put coal gangue into a crusher for crushing and screening to obtain coal gangue particles with a particle size of less than 0.9 mm; weigh coal gangue, slag, fly ash, cement, quartz sand, waste glass, and basalt fiber according to the ratio; Weigh the water reducing agent and water, stir the two evenly, pour them into the raw materials, and stir with a mixer. After uniform stirring, obtain the pretreated material; Pour the pretreated material evenly into the mold. This operation should be placed on a vibrating table to ensure that it is filled evenly and smoothly. Place the mold filled with the pretreated material on a flat, dry, and ventilated site for curing for 3 days, and demold to obtain the artificial lightweight aggregate; standing for 3 days can make the substances contact more fully, and the slurry can solidify; Collect the artificial lightweight aggregate, put it into container C, pour in water to cover the surface, and cure for 28 days to obtain the finished artificial lightweight aggregate.

[0058] Example 3 A coal-based multi-solid waste artificial lightweight aggregate, comprising raw materials with the following masses: 6.190 kg of fly ash, 5.158 kg of cement, 3.300 kg of coal gangue, 4.127 kg of waste glass, 3.766 kg of water, 0.105 kg of basalt fiber, 0.830 kg of quartz sand, and 0.01 kg of water reducing agent. Denote it as G3.

[0059] This example also includes the preparation method of the coal-based multi-solid waste artificial lightweight aggregate, and the steps are as follows: Select natural crushed coarse aggregate particles with sizes of 10 - 15 mm, 15 - 20 mm, and 20 - 30 mm, wash and dry them, and place them in container A for standby. Mix silica gel A of model GH~636 and silica gel B strictly according to a mass ratio of 1:1, place them in container B, and use a mixer to stir for 5 minutes until uniform.

[0060] Use the turning mold prepared in Example 1; Put coal gangue into a crusher for crushing and screening to obtain coal gangue particles with a particle size below 0.9 mm; weigh coal gangue, slag, fly ash, cement, waste glass, and basalt fiber in proportion; Weigh the water reducing agent and water, stir the two evenly, pour them into the raw materials, and use a mixer to stir. After uniform stirring, obtain the pretreated material; Pour the pretreated material evenly into the turning mold. This operation should be placed on a vibrating table to ensure full and flat filling. Place the turning mold filled with the pretreated material in a flat, dry, and ventilated area for curing for 3 days, and then demold to obtain artificial lightweight aggregate; standing for 3 days can make the substances contact more fully, and the slurry can solidify; Collect the artificial lightweight aggregate, put it into container C, pour water over the surface, and cure for 28 days to obtain the finished product of artificial lightweight aggregate.

[0061] Example 4 A coal-based multi-solid waste artificial lightweight aggregate, including raw materials with the following masses: Fly ash 6.190 kg, cement 1.032 kg, water 3.766 kg, basalt fiber 0.105 kg, waste glass 0.830 kg, slag 4.127 kg, coal gangue 3.300 kg, and water reducing agent 0.02 kg. Denote it as G4.

[0062] This example also includes the preparation method of this coal-based multi-solid waste artificial lightweight aggregate, and the steps are as follows: Select natural crushed coarse aggregate particles with sizes of 10 - 15 mm, 15 - 20 mm, and 20 - 30 mm, wash and dry them, and place them in container A for standby. Mix silica gel A of model GH~636 and silica gel B strictly according to a mass ratio of 1:1, place them in container B, and use a mixer to stir for 5 minutes until uniform.

[0063] Use the turning mold prepared in Example 1; Put coal gangue into a crusher for crushing and screening to obtain coal gangue particles with a particle size below 0.9 mm; weigh coal gangue, slag, fly ash, cement, waste glass, and basalt fiber in proportion; Weigh the water reducing agent and water, stir the two evenly, pour them into the raw materials, and use a mixer to stir. After uniform stirring, obtain the pretreated material; Pour the pretreated material evenly into the mold, and this operation should be carried out on a vibrating table to ensure full and flat filling. Place the mold with the pretreated material in a flat, dry and ventilated area for curing for 3 days, and then demold to obtain artificial lightweight aggregate. Standing for 3 days can make the substances contact more fully, and the slurry can solidify. Collect the artificial lightweight aggregate, put it into container C, pour water to submerge the surface, and cure for 28 days to obtain the finished product of artificial lightweight aggregate.

[0064] Example 5 A coal-based multi-solid waste artificial lightweight aggregate, including raw materials with the following masses: 6.190 kg of fly ash, 1.032 kg of cement, 3.720 kg of coal gangue, 3.766 kg of water, 0.105 kg of basalt fiber, 0.420 kg of waste glass, 4.127 kg of slag and 0.02 kg of water reducing agent. Recorded as G5.

[0065] The preparation method is the same as that in Example 4 to obtain the finished aggregate product.

[0066] Considering various factors such as the physical properties, mechanical characteristics, economy and environmental protection of the materials, through systematic tests and analyses, it is determined that the mixing ratio scheme of artificial lightweight aggregate G5 performs the best. The water absorption rate of this lightweight aggregate is 7.19%, and the crushing value index reaches 12.12%, showing good structural stability and durability. After 28 days of standard curing, the compressive strength of the cubic concrete specimens (model M5) prepared on this basis reaches 36.21 MPa, fully verifying that the G5 mixing ratio has excellent mechanical properties and application potential in practical applications.

[0067] Example 6 A coal-based multi-solid waste artificial lightweight aggregate, including raw materials with the following masses: 6.190 kg of fly ash, 1.032 kg of cement, 3.766 kg of water, 0.105 kg of basalt fiber, 4.127 kg of slag, 4.130 kg of coal gangue and 0.02 kg of water reducing agent. Recorded as G6.

[0068] This example also includes the preparation method of this coal-based multi-solid waste artificial lightweight aggregate, and the steps are as follows: Select natural crushed stone coarse aggregate particles of 10 - 15 mm, 15 - 20 mm and 20 - 30 mm, wash and dry them, and put them into container A for standby. Mix silica gel A of model GH - 636 and silica gel B strictly according to a mass ratio of 1:1, place them in container B, and stir with a mixer for 5 minutes until uniform.

[0069] Use the mold prepared in Example 1; Take coal gangue and put it into a crusher for crushing and screening to obtain coal gangue particles with a particle size below 0.9 mm; Weigh coal gangue, slag, fly ash, cement, waste glass, and basalt fiber in proportion; Weigh water reducer and water, stir the two evenly, pour them into the raw materials, and use a mixer to stir. After uniform stirring, a pretreated material is obtained; Pour the pretreated material evenly into a turnover mold. This operation should be placed on a vibrating table to ensure that it is filled evenly and smoothly. Place the turnover mold filled with the pretreated material in a flat, dry, and ventilated area for curing for 3 days (days), and demold to obtain artificial lightweight aggregate; Standing for 3 days can make the substances contact more fully, and the slurry can solidify; Collect the artificial lightweight aggregate, put it into container C, pour water over the surface, and cure for 28 days to obtain the finished product of artificial lightweight aggregate.

[0070] Example 7 A coal-based multi-solid waste artificial lightweight aggregate, including raw materials with the following masses: 4.647 kg of fly ash, 1.032 kg of cement, 4.130 kg of coal gangue, 3.766 kg of water, 0.105 kg of basalt fiber, 5.670 kg of slag, and 0.02 kg of water reducer. Recorded as G7.

[0071] The preparation method is the same as that of Example 4 to obtain the finished aggregate.

[0072] Example 8 To further verify the feasibility of the artificial lightweight aggregate, the artificial lightweight aggregates prepared in Examples 1 to 7 of the present invention are used to prepare C30 concrete specimens, which are respectively recorded as M1 to M7; Among them, the components of the G1 to G7 artificial lightweight aggregates are shown in Table 5.

[0073] Table 5. Components of G1 to G7 artificial lightweight aggregates

[0074] Select natural crushed stone coarse aggregate particles with the same particle shape coefficient and gradation to prepare the same grade cubic concrete specimens as the control group M0, and the natural crushed stone coarse aggregate particle gradation is G0; Conduct cubic compressive strength tests on the M0 to M7 artificial lightweight aggregate concretes respectively.

[0075] Select raw materials to make concrete specimens, and the mix ratio should ensure that the volume of all aggregates is the same. Then each group includes raw materials with the following masses: Table 6. Components of C30 cubic concrete specimens

[0076] First, weigh all the required raw materials according to the requirements; Subsequently, use a stirrer to fully stir all the raw materials until they are uniform; Finally, place a mold for turning over with a cube structure of 150*150*150 mm on a vibrating table, and pour in the concrete slurry; after natural curing for 28 days, specimens are obtained, and their compressive strength is tested; Figure 11 It is a schematic diagram of the compressive strength results of cube concrete specimens; Figure 12 In (a) and (b), they are the compressive failure schematic diagrams of M0 and M5 respectively; From Figure 11 it can be seen that the compressive strength of the natural crushed stone coarse aggregate particle concrete specimen M0 is 37.13 MPa. The compressive strengths of the artificial lightweight aggregate concrete specimens M1, M2, and M3 are 36.17 MPa, 34.28 MPa, and 30.04 MPa respectively. Among them, the strength of M1 is slightly higher than that of M0. Combining Figure 12 it can be seen that the mortar phase (marked by the red circle) inside M0 is relatively loose. In M5, the basalt fiber effectively improves the compactness of the mortar phase and the performance of the interfacial transition zone, inhibits the development of microcracks, and thus enhances the structural integrity and crack resistance. In addition, neither the natural crushed stone coarse aggregate particles nor the artificial lightweight aggregate G1 (the coarse aggregate is marked by the blue circle) showed obvious breakage during the failure process, and it can be observed that the combination of the artificial lightweight aggregate and the slurry is more uniform and tight, without obvious protrusions of the natural crushed stone coarse aggregate particles, showing good bearing capacity. With the decrease of the cement dosage and the increase of the coal gangue particle content in M4–M7, the pore structure of the concrete is effectively improved, and the compressive strengths reach 32.14 MPa, 36.21 MPa, 34.21 MPa, and 35.70 MPa respectively, which are close to M0 and all meet the requirements of the C30 strength grade. From Figure 12 as observed in (b), the coal gangue particles play a positive role in filling pores and improving the structural compactness. At the same time, the basalt fiber wraps around the surface of the aggregate, significantly enhancing the bonding performance of the interfacial transition zone (ITZ) and effectively inhibiting the expansion of microcracks. At the same time, M4~M7 show better environmental protection performance while maintaining mechanical properties, and have good promotion prospects. Figure 12 It can also be seen that the failure mode of the artificial lightweight aggregate concrete and the natural crushed stone coarse aggregate particle concrete both show typical "inverted cone" failure characteristics; the performance of the G3 artificial lightweight aggregate is relatively weak, resulting in a decrease in the compressive strength of M3.

[0077] Figures 3 to 11 They are the test results of the artificial lightweight aggregates in the example group. Taking Example G1 as the control group, in Examples G2~G7, the aggregate ratio is optimized on the premise of keeping the water-binder ratio unchanged, the cement dosage is gradually reduced, the coal gangue particle dosage and the cementitious material substitution rate are increased, aiming to achieve low-carbon environmental protection while meeting the specification requirements.

[0078] From Figure 3 ,Figure 4 It can be seen that the bulk densities of the artificial lightweight aggregate examples G1 to G7 are all between 800 and 900 and the apparent densities are between 1789.37 and 2047.23 , meeting the requirements for lightweight coarse aggregates of density grade 900 in Article 5.2 of "Lightweight Aggregates and Their Test Methods - Part 1: Lightweight Aggregates" GB / T 17431.1~2010; From Figure 5 it can be seen that the water absorption rates of G1, G2, and G3 are 9.88%, 9.32%, and 11.56% respectively; among them, the water absorption rate of G2 decreases due to the incorporation of coal gangue particles, which reduces the porosity; the water absorption rate of G3 increases significantly because a large amount of waste glass is incorporated, resulting in an increase in porosity due to the irregular particles. G4–G7 effectively improve the pore structure by reducing the cement and waste glass usage and increasing the cementitious material replacement rate, and the water absorption rates are reduced to 8.46%, 7.19%, 9.83%, and 9.65%, approaching G1 and G2, showing better green performance. Except for G3, the other groups all meet the requirement that the water absorption rate of lightweight coarse aggregates of density grade 900 in Article 5.4.1 of "Lightweight Aggregates and Their Test Methods - Part 1: Lightweight Aggregates" GB / T 17431.1~2010 should not be greater than 10%.

[0079] From Figure 6 it can be seen that the crushing value indexes of G1, G2, and G3 are 9.52%, 9.27%, and 15.18% respectively; among them, the crushing index of G2 decreases slightly with the incorporation of coal gangue particles; in the G3 group, due to the excessive content of waste glass, the brittleness of the aggregate is significantly enhanced, the compressive performance decreases, and it is prone to breakage under pressure. The G4~G7 groups achieve a more reasonable balance between lightweight and mechanical properties by optimizing the cement and waste glass usage and increasing the cementitious material replacement rate. Although their crushing values increase, they are 14.05%, 12.12%, 13.65%, and 13.62% respectively. All experimental groups meet the relevant requirements of "Standard for Quality and Inspection Methods of Sand and Aggregates for Ordinary Concrete". It should be noted that there is generally a positive correlation between the crushing value of artificial lightweight aggregate and its water absorption rate, that is, the lower the water absorption rate, the better the crushing resistance performance of the aggregate.

[0080] Figure 7 , Figure 8 Figures (a) in are the SEM micrographs of Examples 2 and 3. It can be seen that the hydration reaction inside the aggregate is relatively sufficient, and there is no large accumulation of calcium hydroxide (CH) crystals, indicating that there is less free Ca(OH)2 in the system, which is beneficial to improving the long-term durability of the material. Figure 8 In (a), it shows that the main hydration product under water curing conditions is calcium silicate hydrate (C~S~H), which significantly fills the pores and enhances the structural stability of the matrix. In addition, the surface layer structure of the matrix is compact and the surface is rough, which helps to improve the bonding strength of the interfacial transition zone and the overall compressive performance; Figure 9 As can be clearly observed in Figure (a), a large number of needle-shaped AFt (ettringite) have been formed on both the matrix and the surface of basalt fibers. Figure 9 Figure (b) shows the staggered and embedded distribution of basalt fibers in the matrix, effectively inhibiting the expansion of microcracks and improving the toughness and crack resistance of the composite material. In addition, not only are basalt fibers embedded inside the aggregates in the example group, but basalt fibers are also evenly distributed on their outer surfaces, achieving all-round reinforcement from the aggregate core to the interface area. This distribution form optimizes the interfacial transition zone between the concrete mortar and the aggregates, significantly improving the compressive strength of the concrete and demonstrating excellent comprehensive mechanical properties.

[0081] The present invention also provides the following examples for preparing coal-based multi-solid waste artificial lightweight aggregates.

[0082] Example 9 A coal-based multi-solid waste artificial lightweight aggregate, comprising raw materials with the following masses: Fly ash 6.190 kg, cement 1.032 kg, water 3.766 kg, basalt fiber 0.105 kg, waste glass 0.42 kg, slag 4.127 kg, coal gangue 3.720 kg, and water reducing agent 0.015 kg.

[0083] This example also includes a preparation method for the coal-based multi-solid waste artificial lightweight aggregate, and the steps are as follows: Select natural crushed stone coarse aggregate particles with sizes of 10 - 15 mm, 15 - 20 mm, and 20 - 30 mm, wash and dry them, and place them in container A for standby. Silicone A and silicone B with the model GH - 636 are strictly mixed according to a mass ratio of 1:1, placed in container B, and stirred with a mixer for 5 minutes until uniform.

[0084] Subsequently, pour the mixed silicone liquid into container A containing natural crushed stone coarse aggregate particles, ensuring that the natural crushed stone coarse aggregate particles are completely covered by the silicone liquid. Let it stand for 3 hours. After the silicone liquid cures, take out the natural crushed stone coarse aggregate particles to obtain a mold for preparing aggregates; repeat this step to obtain the mold. Put coal gangue into a crusher for crushing and screening to obtain coal gangue particles with a particle size of less than 0.9 mm; weigh coal gangue, slag, fly ash, cement, waste glass, and basalt fiber according to the ratio. Weigh the water reducing agent and water, stir the two evenly, pour them into the raw materials, and stir with a mixer. After uniform stirring, a pretreated material is obtained. Pour the pretreated material evenly into the mold - turning mold. This operation should be carried out on a vibrating table to ensure full and flat filling. Place the mold - turning mold filled with the pretreated material in a flat, dry and well - ventilated area for curing for 3 days, and then demold to obtain artificial lightweight aggregates. The 3 - day static treatment can enable substances to contact more fully, and the slurry can solidify. Collect the aggregates and put them into container C. Pour water to submerge the surface and cure for 28 days to obtain the finished aggregates.

[0085] Example 10 A coal - based multi - solid - waste artificial lightweight aggregate, comprising raw materials with the following masses: 6.0 kg of fly ash, 1.0 kg of cement, 3.6 kg of water, 0.1 kg of basalt fiber, 0.4 kg of waste glass, 4.0 kg of slag, 3.3 kg of coal gangue, and 0.01 kg of water - reducing agent.

[0086] This example also includes the preparation method of the coal - based multi - solid - waste artificial lightweight aggregate, and the steps are as follows: Select natural crushed stone coarse aggregate particles with sizes of 10 - 15 mm, 15 - 20 mm, and 20 - 30 mm, wash and dry them, and put them into container A for standby. Mix silica gel A of model GH - 636 and silica gel B strictly according to a mass ratio of 1:1, place them in container B, and stir with a mixer for 3 minutes until uniform.

[0087] Subsequently, pour the mixed silica gel liquid into container A containing natural crushed stone coarse aggregate particles to ensure that the natural crushed stone coarse aggregate particles are completely covered by the silica gel liquid. Let it stand for 3 hours. After the silica gel liquid solidifies, take out the natural crushed stone coarse aggregate particles to obtain the mold - turning mold for preparing aggregates; repeat this step to obtain the mold - turning mold. Put coal gangue into a crusher for crushing and screening to obtain coal gangue particles with a particle size below 0.9 mm; weigh coal gangue, slag, fly ash, cement, waste glass, and basalt fiber according to the ratio. Weigh the water - reducing agent and water, stir them evenly, pour them into the raw materials, and stir with a mixer. After uniform stirring, obtain the pretreated material. Pour the pretreated material evenly into the mold - turning mold. This operation should be carried out on a vibrating table to ensure full and flat filling. Place the mold - turning mold filled with the pretreated material in a flat, dry and well - ventilated area for curing for 3 days, and then demold to obtain artificial lightweight aggregates. The 3 - day static treatment can enable substances to contact more fully, and the slurry can solidify. Collect the aggregates and put them into container C. Pour water to submerge the surface and cure for 28 days to obtain the finished aggregates.

[0088] Figure 10The XRD patterns of Example Groups 5, 6, and 7 show that all three aggregate groups contain quartz, calcite, ettringite, and carbonate minerals, demonstrating a reasonable overall mineral composition. The diffraction peaks are densely distributed. A comparison shows that the intensity of the calcite diffraction peak increases with increasing gangue content, primarily because the presence of crystalline quartz (SiO2) in gangue makes it less susceptible to hydration. This multi-mineral aggregate not only exhibits excellent mechanical properties but also contributes to improved concrete stability and durability, achieving a good balance between lightweighting and structural performance.

[0089] Embodiment 11 A coal-based multi-solid waste artificial lightweight aggregate, comprising the following raw materials: 4.65 kg of fly ash, 5.2 kg of cement, 3.8 kg of water, 0.2 kg of basalt fiber, 0.9 kg of waste glass, 4.2 kg of slag, 4.2 kg of coal gangue and 0.02 kg of water reducer.

[0090] This embodiment also includes a method for preparing the coal-based multi-solid waste artificial lightweight aggregate, which comprises the following steps: Select 10-20mm and 20-30mm natural crushed stone coarse aggregate particles, wash and dry them, and place them in container A for later use. Strictly mix GH-636 silica gel A and silica gel B in a 1:1 mass ratio, place them in container B, and stir them in a blender for 3 minutes until uniform.

[0091] Then, pour the mixed silica gel mixture into container A containing natural crushed stone coarse aggregate particles, ensuring that the natural crushed stone coarse aggregate particles are completely covered by the silica gel mixture. Let it stand for 3 hours. After the silica gel mixture solidifies, remove the natural crushed stone coarse aggregate particles, thus obtaining a remolding mold for preparing aggregate. Repeat this step to obtain a remolding mold. Put the coal gangue into a crusher for crushing and screening to obtain coal gangue particles with a particle size of less than 0.9 mm; weigh the coal gangue, slag, fly ash, cement, waste glass and basalt fiber according to proportion; Weigh the water reducer and water, mix them evenly, pour them into the raw materials, and stir them with a mixer until they are evenly stirred to obtain the pretreated material; Pour the pre-treated material evenly into the mold. This operation should be carried out on a vibrating table to ensure that it is filled fully and evenly. Place the mold filled with the pre-treated material in a flat, dry and ventilated place and cure for 3 days. De-mould and obtain artificial lightweight aggregate. The 3-day static treatment allows for more complete contact between the various materials and allows the slurry to solidify. The aggregate is collected and placed in container C. Water is poured in to cover the surface and the aggregate is cured for 28 days to obtain the finished aggregate product.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A preparation method of a coal-based multi-solid waste artificial lightweight aggregate, characterized in that, It includes the following steps: Select natural crushed coarse aggregate particles and perform grading to form a coarse aggregate set; After washing the coarse aggregate set, immerse it in a silica gel mixture. After the silica gel mixture solidifies, take out the natural crushed coarse aggregate particles to obtain a mold for preparing aggregates; Add fly ash, cement, and basalt fiber to the crushed coal gangue; then add a mixture of water reducer and water, and mix and stir evenly to obtain a pretreated material; the mass ratio of the coal gangue, fly ash, cement, basalt fiber, water reducer, and water is (3.3~4.2):(4.6~6.2):(1.0~5.2):(0.1~0.2):(0.01~0.02):(3.6~3.8); Pour the pretreated material into the mold, and after one natural curing, demold after the pretreated material solidifies to obtain artificial lightweight aggregates; after the artificial lightweight aggregates are subjected to secondary natural curing, a finished product of coal-based multi-solid waste artificial lightweight aggregates is obtained.

2. The preparation method of the coal-based multi-solid waste artificial lightweight aggregate according to claim 1, characterized in that, The coarse aggregate set is composed of natural crushed coarse aggregate particles with particle sizes of 10~15mm, 15~20mm, and 20~30mm mixed together.

3. The preparation method of the coal-based multi-solid waste artificial lightweight aggregate according to claim 1, characterized in that, The shape coefficient of the natural crushed coarse aggregate particles is 0.65~0.

95.

4. The preparation method of the coal-based multi-solid waste artificial lightweight aggregate according to claim 1, characterized in that, The condition for the silica gel mixture to solidify is to air dry naturally at 15~25°C for 3~5h.

5. The preparation method of the coal-based multi-solid waste artificial lightweight aggregate according to claim 1, characterized in that, The particle size of the coal gangue is below 0.9mm.

6. The preparation method of the coal-based multi-solid waste artificial lightweight aggregate according to claim 1, characterized in that, It also includes slag and waste glass; The mass ratio of the coal gangue to the slag and waste glass is (3.3~4.2):(4.0~5.7):(0.42~4.2).

7. The preparation method of the coal-based multi-solid waste artificial lightweight aggregate according to claim 1, characterized in that, The time for the first natural curing is 3 days; the time for the second natural curing is 28 days.

8. A coal-based multi-solid waste artificial lightweight aggregate, characterized in that, It is prepared by using the preparation method of the coal-based multi-solid waste artificial lightweight aggregates described in any one of claims 1~7.

9. The coal-based multi-solid waste artificial lightweight aggregate according to claim 8, wherein The water absorption rate of the coal-based multi-solid waste artificial lightweight aggregate is 7.19% - 11.56%; the apparent density is 1789.37 - 2047.23 kg / cm 3 ; the bulk density is 793.11 - 848.36 kg / cm 3 ; the crushing value index is 9.27% - 15.18%.

10. An application of the coal-based multi-solid waste artificial lightweight aggregates described in claim 8 in the preparation of building materials.

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