Coal-based multi-element solid waste artificial light aggregate, preparation method and application thereof

Abstract

The application discloses coal-based multi-element solid waste artificial light aggregate and a preparation method and application thereof, and belongs to the technical field of solid waste resource utilization, and the preparation method comprises the following steps: selecting natural broken stone coarse aggregate particles, grading to form a coarse aggregate set; after the coarse aggregate set is cleaned, the natural broken stone coarse aggregate particles are taken out after being immersed in a silica gel mixed solution, and a turnover mold for preparing the aggregate is obtained after the silica gel mixed solution is solidified; fly ash, cement and basalt fibers are added to crushed coal gangue; a mixture of a water reducing agent and water is further added, and the mixture is uniformly mixed and stirred to obtain pretreated material; the pretreated material is poured into the turnover mold, and artificial light aggregate is obtained after demolding; and finally, the coal-based multi-element solid waste artificial light aggregate is obtained. Through the self-made turnover mold, the shape and particle grading of the coarse aggregate can be accurately controlled, and the basalt fiber silk in the interface transition zone attached to the surface of the artificial light aggregate can improve the problems of low replacement rate, high dispersity and brittle failure of the coal gangue as the concrete coarse aggregate.

Description

Technical Field

[0001] This invention belongs to the field of new building materials and solid waste resource utilization technology, specifically relating to a coal-based multi-element solid waste artificial lightweight aggregate, its preparation method and application. Background Technology

[0002] The unprecedented speed and scale of construction projects have led to a year-on-year increase in the demand for sand and gravel aggregates. Quarrying and sand mining have severely damaged the ecological environment. To resolve this prominent contradiction between large-scale construction and environmental protection, there is an urgent need to develop corresponding alternative "artificial aggregates." Coal gangue, as one of the largest solid wastes in terms of emissions, has a comprehensive utilization rate of less than 60%. Large-scale stockpiling not only occupies land resources but also pollutes the environment, damages vegetation, and triggers geological disasters such as landslides, mudslides, and debris flows. Faced with the current situation of high-volume, high-risk coal gangue stockpiling, how to turn waste into treasure, reduce environmental pollution, and shift from "primarily stockpiling" to "primarily utilization" has become one of the social problems that scientists urgently need to solve.

[0003] Currently, coal gangue is mainly used as a building material: (1) Crushing coal gangue and using it directly as coarse aggregate to prepare concrete can effectively solve the problem of coal gangue stockpiling, reduce environmental pollution, and alleviate the shortage of natural sand and gravel resources. However, the strength of coal gangue varies greatly depending on the region, rock strata, and structure. Crushed coal gangue exhibits high fissures, high water absorption, and high dust characteristics. The strength of coal gangue concrete has strong randomness and dispersion, and it is also brittle and prone to cracking, which limits its application in engineering. (2) Using coal gangue instead of 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 drawbacks such as high energy consumption, high cost, and complicated roasting process, which is not conducive to the transformation to a green industry that saves energy and reduces emissions, and is contrary to the development concept of a global low-carbon circular economy. Therefore, there is an urgent need for a method that can eliminate the dispersion of coal gangue and has the characteristics of low carbon and environmental protection in the preparation of concrete and cement-related products.

[0004] Cold-bonded granulation technology for preparing artificial aggregates first involves agglomerating powdered or muddy waste into pellets of the desired size, and then using curing processes (such as sintering, water curing, wet curing, and carbonization) to give the artificial lightweight aggregate pellets a certain strength. Cold-bonded granulation processes are mainly divided into two categories: extrusion molding and mixing granulation. These methods primarily process powdered materials into agglomerated materials that meet specific shapes, compositions, and densities using specific equipment and methods. Most existing cold-bonded granulation technologies produce aggregates that are spherical or near-spherical. Spherical aggregates present several problems regarding concrete strength and durability. For example, spherical aggregates are prone to stress concentration under load, leading to localized cracking and lower compressive strength; they are more easily broken under impact and compression, exhibiting higher abrasion and poorer stability; they have weak frost resistance and fatigue resistance, easily accumulating microcracks under repeated loading conditions, leading to material failure; and the interface transition zone between spherical aggregates and mortar is relatively weak. While the preparation of artificial coarse aggregates based on cold bonding technology is feasible to some extent, the resulting particle shapes are relatively uniform, the gradation is poor, and the bonding ability with the mortar interface is weak. Furthermore, the preparation process is complex, and there are no reports on the use of cold bonding technology to prepare lightweight artificial aggregates from coal-based solid waste. Therefore, further improvements are needed to 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 shortcomings of the prior art, the present invention aims to provide a coal-based multi-element solid waste artificial lightweight aggregate, its preparation method and application. By efficiently utilizing coal gangue, an artificial lightweight aggregate with controllable particle size and shape and basalt fiber filaments bonded to the surface interface transition zone is 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 objectives, the present invention employs the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing coal-based multi-element solid waste artificial lightweight aggregate, comprising the following steps:

[0008] Select natural crushed stone coarse aggregate particles and grade them to form coarse aggregate aggregate;

[0009] After cleaning the coarse aggregate, it is immersed in the silica gel mixture. After the silica gel mixture solidifies, the natural crushed stone coarse aggregate particles are removed to obtain a mold for preparing aggregate.

[0010] Fly ash, cement, and basalt fiber are added to the crushed coal gangue; then a mixture of water-reducing agent and water is added and stirred evenly to obtain a pretreated material; the mass ratio of coal gangue, fly ash, cement, basalt fiber, water-reducing agent, 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).

[0011] The pretreated material is poured into the mold and cured naturally once. After the pretreated material solidifies, it is demolded to obtain artificial lightweight aggregate. After the artificial lightweight aggregate is cured naturally a second time, the finished product of coal-based multi-element solid waste artificial lightweight aggregate is obtained.

[0012] As a further improvement of the present invention, the coarse aggregate is a mixture of natural crushed stone coarse aggregate particles with particle sizes of 10~15mm, 15~20mm and 20~30mm.

[0013] As a further improvement of the present invention, the shape coefficient of the natural crushed stone coarse aggregate particles is 0.65~0.95.

[0014] As a further improvement of the present invention, the curing conditions of the silicone mixture are: natural air drying at 15~25℃ for 3~5 hours.

[0015] As a further improvement of the present invention, the particle size of the coal gangue is less than 0.9 mm.

[0016] As a further improvement to the present invention, it also includes slag and waste glass;

[0017] The mass ratio of coal gangue to slag and waste glass is (3.3~4.2):(4.0~5.7):(0.42~4.2).

[0018] As a further improvement of the present invention, the time for the first natural maintenance is 3 days; the time for the second natural maintenance is 28 days.

[0019] Secondly, the present invention provides a coal-based multi-element solid waste artificial lightweight aggregate, which is prepared by the aforementioned method for preparing coal-based multi-element solid waste artificial lightweight aggregate.

[0020] Preferably, the water absorption rate of the coal-based multi-element solid waste artificial lightweight aggregate is 7.19%~11.56%; the apparent density is 1789.37~2047.23 kg / cm³. 3 The bulk density is 793.11~848.36 kg / cm³. 3 The crushing value ranges from 9.27% ​​to 15.18%.

[0021] Thirdly, the present invention provides the application of the coal-based multi-element solid waste artificial lightweight aggregate prepared by the method described above in the preparation of building materials.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention discloses a method for preparing coal-based multi-element solid waste artificial lightweight aggregate. It utilizes coal gangue particles, fly ash, and other multi-element solid waste to prepare artificial lightweight aggregate with controllable particle size and shape, and adds basalt fibers to create an interfacial transition zone that binds the basalt fiber filaments to the aggregate surface. Specifically: First, the crushed coal gangue particles eliminate many defects such as pores and cracks found in the original coal gangue, effectively realizing the synergistic effect of the multi-element coal-based solid waste, eliminating gaps between different particles, enhancing the compactness of the artificial aggregate, and effectively improving the physical and mechanical properties and molding effect of the aggregate. Second, the prepared silica gel material can effectively intervene in and optimize the particle size and shape of the coarse aggregate, precisely adjusting the gradation distribution of the coarse aggregate, increasing its bulk density, and thus enhancing its compaction value, effectively improving the physical and mechanical properties of concrete. Third: Basalt fiber has a high elastic modulus, good silicate compatibility and a thermal expansion coefficient similar to that of concrete. Adding basalt fiber to artificial aggregates can not only effectively improve the aggregate toughness, but also the basalt fiber filaments attached to its surface can form a network structure in the mortar interface transition zone, which enhances the mechanical properties and durability of concrete.

[0024] This invention presents a novel approach to the resource utilization of coal gangue, offering significant advantages in carbon reduction and utilization. These advantages make it a promising candidate for widespread application in construction and infrastructure projects. This method effectively reduces the extensive use of cement in traditional formulations, thereby lowering raw material costs and avoiding indirect carbon emissions associated with cement use. By using a self-made molding die, the particle size and shape of the multi-element coal-based solid waste artificial lightweight aggregate can be precisely controlled. Furthermore, the required equipment is simple, the preparation process does not require high-temperature calcination, saving energy, and the necessary materials are readily available, achieving the goal of low raw material costs, low operating costs, and low construction costs. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the preparation of coal-based multi-element solid waste artificial lightweight aggregate using the mold flipping method of this invention;

[0026] Figure 2 This is a flowchart of the preparation process of coal-based multi-element solid waste artificial lightweight aggregate disclosed in this invention;

[0027] Figure 3 This is a graph showing the packing density results for all embodiments of the present invention;

[0028] Figure 4The above figures show the apparent density results for all embodiments of the present invention.

[0029] Figure 5 The graph shows the water absorption rate results for all embodiments of the present invention.

[0030] Figure 6 The graph shows the crushing value index results for all embodiments of the present invention.

[0031] Figure 7 The images shown are SEM (Scanning Electron Microscope) test images of the coal-based multi-component solid waste artificial lightweight aggregate disclosed in Embodiment 5 of the present invention; wherein, (a) and (b) are schematic diagrams of hydration products in the coal-based multi-component solid waste artificial lightweight aggregate.

[0032] Figure 8 The image shown is a SEM image of the coal-based multi-element solid waste artificial lightweight aggregate disclosed in Example 6 of this invention; wherein, (a) is a magnified image of 5. (a) Internal view of artificial lightweight aggregate; (b) Enlarged 20 mm Internal view of artificial lightweight aggregate;

[0033] Figure 9 The image shown is a SEM image of the coal-based multi-element solid waste artificial lightweight aggregate disclosed in Example 5 of this invention; wherein, (a) is a magnified image at 20°. (a) Schematic diagram of basalt fibers and hydrated materials inside artificial lightweight aggregate; (b) is a magnified view of 100 mm. Distribution of basalt fibers;

[0034] Figure 10 The XRD (X-ray Diffraction) patterns of the coal-based multi-element solid waste artificial lightweight aggregates disclosed in Examples 5, 6 and 7 of this invention are shown below.

[0035] Figure 11 This is a schematic diagram showing the compressive strength results of a cubic concrete specimen.

[0036] Figure 12 The diagrams are schematic diagrams of compressive failure of cubic concrete specimens in this invention, wherein (a) is a schematic diagram of compressive failure of M0 cubic concrete specimen; and (b) is a schematic diagram of compressive failure of M5 cubic concrete specimen. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0039] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0040] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0041] In this invention, unless otherwise specified, the components involved or their preferred components can be combined to form new technical solutions.

[0042] In this invention, unless otherwise specified, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6~22" indicates that all real numbers between "6~22" have been listed in this document, and "6~22" is simply a shortened representation of these numerical combinations.

[0043] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0044] In this invention, the term "and / or" as used herein refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0045] In this invention, unless otherwise stated, the various reaction or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0046] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0047] To address the problems of high material property dispersion, low strength, high randomness, brittle fracture, and high energy consumption and high cost of traditional utilization methods when coal gangue is used directly as a raw material for concrete and cement products, based on existing cold bonding granulation technology, it is urgent to propose a new coal-based multi-element solid waste artificial lightweight aggregate and its preparation method. This artificial lightweight aggregate should have a high coal-based solid waste replacement rate, controllable particle size and shape, and basalt fiber filaments bonded to the surface interface transition zone, thereby achieving efficient, environmentally friendly, and resource-based utilization of coal gangue.

[0048] The coal-based multi-element solid waste artificial lightweight aggregate prepared by the method of this invention is a multi-faceted artificial coarse aggregate that is similar to natural crushed stone coarse aggregate particles. It has high compressive strength, mainly because its edges and corners can distribute the stress more evenly, reducing the risk of local cracking. In addition, its rough surface can form a stronger bond 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.

[0049] Firstly, the filling shape of the mold and the particle size of the aggregate for the coal-based multi-element solid waste artificial lightweight aggregate are optimized:

[0050] Aggregates are the largest filler in concrete by volume. They have high strength and play a supporting role in the overall structure. Aggregates significantly affect the workability of concrete and the interfacial transition zone between concrete and cementitious materials.

[0051] First, 8000g of natural crushed stone coarse aggregate particles were randomly selected, washed, and dried. Due to the complexity and difficulty in determining the shape of natural crushed stone coarse aggregate particles, this invention evaluates the natural crushed stone coarse aggregate particles through the shape particle shape coefficient parameter, and human intervention is used to select natural crushed stone coarse aggregate particles with a measured shape particle shape coefficient value close to 0.65~0.95.

[0052] Preferred coarse aggregates with particle sizes between 10~15mm, 15~20mm and 20~30mm were selected by sieving and set aside. After washing and drying, they were compounded in different proportions, as shown in Table 1.

[0053] Table 1. Particle size distribution parameters of natural crushed stone coarse aggregate with different particle sizes

[0054]

[0055] The crushing value index of coarse aggregates with different gradations in Table 1 was tested according to the test method standard (JGJ 52~2006), and the results are shown in Table 2.

[0056] Table 2. Crushing Value Indicators for Each Grade

[0057]

[0058] As shown in Table 2, when the mass percentage of coarse aggregate with a particle size of 10-15mm in gradation 3 is 5%, the mass percentage of coarse aggregate with a particle size of 15-20mm is 15%, and the mass percentage of coarse aggregate with a particle size of 20-30mm is 80%, the crushing value is the best, thus improving the overall performance. The natural crushed stone coarse aggregate particles of gradation 3 are used as the filler in the mold.

[0059] See Figure 1 This is a schematic diagram of the mold preparation process used in this invention; from Figure 1 As can be seen from this, the methods for preparing the mold for casting include:

[0060] First, strictly mix silica gel A and silica gel B of model GH~636 at a mass ratio of 1:1, pour them into a container, and stir for about 5 minutes until they are completely mixed and there are no bubbles on the surface, thus obtaining a silica gel mixture.

[0061] Both silicone A and silicone B are liquid silicones, existing technology, and are briefly described as follows: GH~636 silicone A and silicone B are two-component addition-curing liquid silicones, mixed in a 1:1 weight ratio. They feature low shrinkage, high temperature resistance (300~500℃), and rapid curing (operating at room temperature for 30 minutes, fully cured in 2~3 hours). The two-component system consists of component A (containing a platinum-based catalyst) and component B (containing a methylhydrosiloxane crosslinking agent and an alcohol inhibitor), and must be mixed in a 1:1 weight ratio. Crosslinking and curing occur through a hydrosilylation reaction. The inhibitor controls the reaction rate after mixing, ensuring controllable operating time. Curing conditions: Room temperature curing; operating time at 28℃ for 30 minutes, fully cured in 2~3 hours. Accelerated curing by heating: at 60~120℃, curing time is shortened to tens of minutes.

[0062] Arrange the natural crushed stone coarse aggregate of grade 3 in Table 2 neatly in the container in sequence. Pour the silica gel mixture into the container in batches. First, pour in a thin layer enough to cover the bottom, and adjust any misaligned natural crushed stone coarse aggregate particles. Second, slowly pour in the silica gel mixture until the natural crushed stone coarse aggregate particles are covered to about two-thirds of the height, and adjust any misaligned particles again. Finally, pour in enough silica gel mixture to make it about 5mm above the surface of all natural crushed stone coarse aggregate particles, ensuring that all particles are completely coated. Finally, place the container in a room temperature (20℃±5℃) environment to air dry naturally for more than 3 hours, until the silica gel surface is no longer sticky and smooth. Then, remove the silica gel mold from the container and remove the natural crushed stone coarse aggregate particles, completing the final mold making process.

[0063] Secondly, coal-based multi-element solid waste artificial lightweight aggregate is prepared, including the following raw materials by weight: cement 1.0~5.2 kg, fly ash 3.3~4.2 kg, basalt fiber 0.1~0.2 kg, waste glass 0.42~4.2 kg, water 3.6~3.8 kg, coal gangue 3.3~4.2 kg, slag 4.0~5.7 kg, and water-reducing agent 0.01~0.02 kg, which can be adjusted appropriately according to the actual situation.

[0064] Table 3. Technical parameters of main raw materials for preparing coal-based multi-element solid waste artificial lightweight aggregates

[0065]

[0066] See Table 3 for the technical parameters of raw materials for preparing coal-based multi-element solid waste artificial lightweight aggregates; Table 3 provides a basic introduction to the relevant raw materials.

[0067] Table 4. Mass ratio of each material in coal-based multi-element solid waste artificial lightweight aggregate per cubic meter

[0068]

[0069] See Table 4 for the mass ratio of each material in the coal-based multi-element solid waste artificial lightweight aggregate per cubic meter; Table 4 shows the mass ratio of each material in the production of coal-based multi-element solid waste artificial lightweight aggregate.

[0070] The core principle of this invention is:

[0071] By human intervention, natural crushed stone coarse aggregate particles with a shape coefficient of 0.65~0.95 are selected, and the particle size distribution of the selected natural crushed stone coarse aggregate particles is optimized to form coarse aggregate.

[0072] After pretreatment (cleaning and drying) of the graded coarse aggregate, it is immersed in silica gel mixture. After the silica gel mixture solidifies, the natural crushed stone coarse aggregate particles are removed to obtain a mold for preparing aggregate.

[0073] Add slag, fly ash, cement, waste glass, and basalt fiber to the crushed coal gangue; then add a mixture of water-reducing agent and water, mix and stir evenly to obtain pretreated material, i.e., the mold granulation method;

[0074] The pretreated material is poured into a mold and cured naturally once. After the pretreated material solidifies, it is demolded to obtain artificial lightweight aggregate. After the artificial lightweight aggregate is cured naturally a second time, the finished product of coal-based multi-element solid waste artificial lightweight aggregate is obtained.

[0075] This invention utilizes a self-made mold-making method combined with a casting granulation technique to precisely control the shape and particle size distribution of coarse aggregates, improving the problems of low replacement rate, high dispersion, and brittle fracture of coal gangue as a coarse aggregate in concrete. It produces an artificial lightweight aggregate with a high coal-based solid waste replacement rate, controllable particle size and shape, and basalt fiber filaments bonded to the surface interface transition zone, effectively achieving the low-carbon and environmentally friendly goals of coal gangue resource utilization. Adding slag, fly ash, cement, waste glass, and basalt fiber to coal gangue forms a synergistic cementitious system that collectively enhances material properties. Cement provides an alkaline environment and generates a large amount of CSH during hydration, which is the main source of strength; slag reacts rapidly in the early stages, improving initial strength; fly ash participates in later reactions, optimizing the structure; waste glass has high activity and also acts as a filler; basalt fiber enhances crack resistance and toughness, while also strengthening the interface transition zone. The complementary cooperation of multiple materials improves strength, density, and durability, compensating for the low activity of coal gangue.

[0076] Furthermore, basalt fiber is a high-performance inorganic basalt fiber made from melted basalt ore through drawing, possessing 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 of coal gangue and basalt fiber lies in the fact that the pozzolanic reaction of coal gangue generates CSH gel, which, together with the crack-resistant effect of basalt fiber, significantly improves compressive, tensile, and flexural strength. The toughening effect of basalt fiber, synergistically with the cementitious products of coal gangue, enables the material to exhibit better deformation capacity and energy absorption capacity under stress. Coal gangue refines the pore structure, while basalt fiber reduces cracks; together, they reduce permeability channels and improve resistance to chloride ion erosion and carbonation. The micro-aggregate effect of coal gangue, synergistically with the "supporting" effect of basalt fiber, reduces segregation and bleeding, and improves concrete fluidity. The confinement effect of basalt fibers, combined with the expansion compensation effect of coal gangue, reduces drying shrinkage and plastic shrinkage.

[0077] like Figure 1 and Figure 2 As shown, the present invention provides a method for preparing coal-based multi-element solid waste artificial lightweight aggregate, including the following steps;

[0078] According to the mass percentage, select 5% high-performance coarse aggregate with a particle size of 10-15mm, 15% coarse aggregate with a particle size of 15-20mm, and 80% coarse aggregate with a particle size of 20-30mm for compounding. Select plump, multi-faceted natural crushed stone coarse aggregate particles (shape coefficient of 0.65-0.95), wash and dry them, and evenly arrange them in container A for later use. Strictly mix silica gel A and silica gel B (model GH-636) at a 1:1 mass ratio, place them in container B, and stir using a mixer for 5 minutes until homogeneous.

[0079] Next, pour the mixed silica gel solution into container A containing natural crushed stone coarse aggregate particles, ensuring that the particles are completely covered by the silica gel solution. Let it stand for 3 hours until the silica gel solution solidifies, then remove the natural crushed stone coarse aggregate particles to obtain a mold for preparing aggregates; repeat this step to obtain multiple molds for later use.

[0080] Coal gangue was crushed and screened in a crusher to obtain coal gangue particles with a diameter of less than 0.9 mm. Coal gangue, slag, fly ash, cement, waste glass and basalt fiber were weighed according to the proportion. Water-reducing agent and water were weighed and mixed evenly, then poured into the raw materials and stirred evenly with a mixer to obtain pretreated material. The pretreated material was evenly poured into a mold, which should be placed on a vibrating table to ensure that it is fully and evenly filled. It was placed in a flat, dry and ventilated place and cured for 3 days until the pretreated material solidified before demolding. The demolded artificial lightweight aggregate was placed in a water-silica gel mixture container C, with the liquid covering the surface of the artificial lightweight aggregate, and cured for 28 days to obtain the finished product of coal-based multi-element solid waste artificial coarse aggregate.

[0081] Figure 3 This is a flowchart of the preparation process of coal-based multi-element solid waste artificial lightweight aggregate disclosed in this invention. As can be seen from the figure, the preparation process includes: weighing all raw materials, mixing water-reducing agent with water and then pouring it into the raw materials for stirring, filling the slurry into the mold, curing for 3 days until the slurry solidifies, taking out the artificial lightweight aggregate particles and placing them in water for curing for 28 days (d refers to days).

[0082] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0083] Example 1

[0084] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0085] The composition is as follows: 6.190 kg fly ash, 5.158 kg cement, 3.766 kg water, 0.105 kg basalt fiber, 4.127 kg quartz sand, and 0.01 kg water-reducing agent. This is designated as G1.

[0086] This embodiment also includes a method for preparing the coal-based multi-element solid waste artificial lightweight aggregate, the steps of which are as follows:

[0087] Select natural crushed stone coarse aggregate particles of 10~15mm, 15~20mm, and 20~30mm, wash and dry them, and place them in container A for later use. Strictly mix silica gel A and silica gel B of type GH~636 at a mass ratio of 1:1, place them in container B, and stir with a mixer for 5 minutes until homogeneous.

[0088] Next, pour the mixed silica gel solution into container A containing natural crushed stone coarse aggregate particles, ensuring that the particles are completely covered by the silica gel solution. Let it stand for 3 hours until the silica gel solution solidifies, then remove the natural crushed stone coarse aggregate particles to obtain a mold for preparing aggregates; repeat this step to obtain multiple molds.

[0089] Take coal gangue and put it into a crusher to crush and screen it to obtain coal gangue particles with a particle size of less than 0.9 mm; weigh out coal gangue, slag, fly ash, cement, quartz sand, waste glass and basalt fiber according to the proportion;

[0090] Weigh out the water-reducing agent and water, mix them thoroughly, pour them into the raw materials, and mix them with a mixer. After mixing evenly, the pretreated material is obtained.

[0091] Pour the pre-treated material evenly into the mold. This operation should be carried out on a vibrating table to ensure that it is fully and evenly filled. Place the mold containing the pre-treated material in a flat, dry and ventilated place and cure for 3 days. After the pre-treated material has solidified, demold to obtain artificial lightweight aggregate. The 3-day curing process allows for more thorough contact between the various materials.

[0092] The artificial lightweight aggregate is collected, placed in container C, and water is poured in to cover the surface. After 28 days of curing, the finished artificial lightweight aggregate is obtained.

[0093] Example 2

[0094] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0095] The composition is as follows: 6.190 kg fly ash, 5.158 kg cement, 3.300 kg coal gangue, 3.766 kg water, 0.105 kg basalt fiber, 0.830 kg quartz sand, and 0.01 kg water-reducing agent. This is designated as G2.

[0096] This embodiment also includes a method for preparing the coal-based multi-element solid waste artificial lightweight aggregate, the steps of which are as follows:

[0097] Select natural crushed stone coarse aggregate particles of 10~15mm, 15~20mm, and 20~30mm, wash and dry them, and place them in container A for later use. Strictly mix silica gel A and silica gel B of type GH~636 at a mass ratio of 1:1, place them in container B, and stir with a mixer for 5 minutes until homogeneous.

[0098] The mold used is the one prepared in Example 1;

[0099] Take coal gangue and put it into a crusher to crush and screen it to obtain coal gangue particles with a particle size of less than 0.9 mm; weigh out coal gangue, slag, fly ash, cement, quartz sand, waste glass and basalt fiber according to the proportion;

[0100] Weigh out the water-reducing agent and water, mix them thoroughly, pour them into the raw materials, and mix them with a mixer. After mixing evenly, the pretreated material is obtained.

[0101] Pour the pre-treated material evenly into the mold. This operation should be carried out on a vibrating table to ensure that it is fully and evenly filled. Place the mold containing the pre-treated material in a flat, dry and ventilated place and cure for 3 days. Demold to obtain artificial lightweight aggregate. The 3-day curing treatment allows for more thorough contact between the materials and allows the slurry to solidify.

[0102] The artificial lightweight aggregate is collected, placed in container C, and water is poured in to cover the surface. After 28 days of curing, the finished artificial lightweight aggregate is obtained.

[0103] Example 3

[0104] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0105] Fly ash 6.190 kg, cement 5.158 kg, coal gangue 3.300 kg, waste glass 4.127 kg, water 3.766 kg, basalt fiber 0.105 kg, quartz sand 0.830 kg, and water-reducing agent 0.01 kg. This is designated as G3.

[0106] This embodiment also includes a method for preparing the coal-based multi-element solid waste artificial lightweight aggregate, the steps of which are as follows:

[0107] Select natural crushed stone coarse aggregate particles of 10~15mm, 15~20mm, and 20~30mm, wash and dry them, and place them in container A for later use. Strictly mix silica gel A and silica gel B of type GH~636 at a mass ratio of 1:1, place them in container B, and stir with a mixer for 5 minutes until homogeneous.

[0108] The mold used is the one prepared in Example 1;

[0109] Coal gangue is crushed and screened in a crusher to obtain coal gangue particles with a particle size of less than 0.9 mm; coal gangue, slag, fly ash, cement, waste glass and basalt fiber are weighed in proportion;

[0110] Weigh out the water-reducing agent and water, mix them thoroughly, pour them into the raw materials, and mix them with a mixer. After mixing evenly, the pretreated material is obtained.

[0111] Pour the pre-treated material evenly into the mold. This operation should be carried out on a vibrating table to ensure that it is fully and evenly filled. Place the mold containing the pre-treated material in a flat, dry and ventilated place and cure for 3 days. Demold to obtain artificial lightweight aggregate. The 3-day curing treatment allows for more thorough contact between the materials and allows the slurry to solidify.

[0112] The artificial lightweight aggregate is collected, placed in container C, and water is poured in to cover the surface. After 28 days of curing, the finished artificial lightweight aggregate is obtained.

[0113] Example 4

[0114] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0115] 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. This is designated as G4.

[0116] This embodiment also includes a method for preparing the coal-based multi-element solid waste artificial lightweight aggregate, the steps of which are as follows:

[0117] Select natural crushed stone coarse aggregate particles of 10~15mm, 15~20mm, and 20~30mm, wash and dry them, and place them in container A for later use. Strictly mix silica gel A and silica gel B of type GH~636 at a mass ratio of 1:1, place them in container B, and stir with a mixer for 5 minutes until homogeneous.

[0118] The mold used is the one prepared in Example 1;

[0119] Coal gangue is crushed and screened in a crusher to obtain coal gangue particles with a particle size of less than 0.9 mm; coal gangue, slag, fly ash, cement, waste glass and basalt fiber are weighed in proportion;

[0120] Weigh out the water-reducing agent and water, mix them thoroughly, pour them into the raw materials, and mix them with a mixer. After mixing evenly, the pretreated material is obtained.

[0121] Pour the pre-treated material evenly into the mold. This operation should be carried out on a vibrating table to ensure that it is fully and evenly filled. Place the mold containing the pre-treated material in a flat, dry and ventilated place and cure for 3 days. Demold to obtain artificial lightweight aggregate. The 3-day curing treatment allows for more thorough contact between the materials and allows the slurry to solidify.

[0122] The artificial lightweight aggregate is collected, placed in container C, and water is poured in to cover the surface. After 28 days of curing, the finished artificial lightweight aggregate is obtained.

[0123] Example 5

[0124] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0125] The composition is as follows: fly ash 6.190 kg, cement 1.032 kg, coal gangue 3.720 kg, water 3.766 kg, basalt fiber 0.105 kg, waste glass 0.420 kg, slag 4.127 kg, and water-reducing agent 0.02 kg. This is designated as G5.

[0126] The preparation method is the same as in Example 4, and the finished aggregate is obtained.

[0127] Taking into account the physical properties, mechanical characteristics, economic efficiency, and environmental friendliness of the materials, systematic testing and analysis determined that the G5 mix proportion of artificial lightweight aggregate exhibited the best performance. This lightweight aggregate has a water absorption rate of 7.19% and a crushing value of 12.12%, demonstrating excellent structural stability and durability. Based on this, cubic concrete specimens (model M5) prepared using this mix proportion achieved a compressive strength of 36.21 MPa after 28 days of standard curing, fully verifying the excellent mechanical properties and application potential of the G5 mix proportion in practical applications.

[0128] Example 6

[0129] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0130] The composition is as follows: 6.190 kg fly ash, 1.032 kg cement, 3.766 kg water, 0.105 kg basalt fiber, 4.127 kg slag, 4.130 kg coal gangue, and 0.02 kg water-reducing agent. This is designated as G6.

[0131] This embodiment also includes a method for preparing the coal-based multi-element solid waste artificial lightweight aggregate, the steps of which are as follows:

[0132] Select natural crushed stone coarse aggregate particles of 10~15mm, 15~20mm, and 20~30mm, wash and dry them, and place them in container A for later use. Strictly mix silica gel A and silica gel B of type GH~636 at a mass ratio of 1:1, place them in container B, and stir with a mixer for 5 minutes until homogeneous.

[0133] The mold used is the one prepared in Example 1;

[0134] Coal gangue is crushed and screened in a crusher to obtain coal gangue particles with a particle size of less than 0.9 mm; coal gangue, slag, fly ash, cement, waste glass and basalt fiber are weighed in proportion;

[0135] Weigh out the water-reducing agent and water, mix them thoroughly, pour them into the raw materials, and mix them with a mixer. After mixing evenly, the pretreated material is obtained.

[0136] Pour the pre-treated material evenly into the mold. This operation should be carried out on a vibrating table to ensure that it is fully and evenly filled. Place the mold containing the pre-treated material in a flat, dry and ventilated place and cure for 3 days. Demold to obtain artificial lightweight aggregate. The 3-day curing treatment allows for more thorough contact between the materials and allows the slurry to solidify.

[0137] The artificial lightweight aggregate is collected, placed in container C, and water is poured in to cover the surface. After 28 days of curing, the finished artificial lightweight aggregate is obtained.

[0138] Example 7

[0139] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0140] 4.647 kg fly ash, 1.032 kg cement, 4.130 kg coal gangue, 3.766 kg water, 0.105 kg basalt fiber, 5.670 kg slag, and 0.02 kg water-reducing agent. This is designated as G7.

[0141] The preparation method is the same as in Example 4, and the finished aggregate is obtained.

[0142] Example 8

[0143] To further verify the feasibility of artificial lightweight aggregates, the artificial lightweight aggregates prepared in Examples 1 to 7 were used to prepare C30 concrete specimens, which were designated as M1 to M7 respectively; the composition of artificial lightweight aggregates G1 to G7 is shown in Table 5.

[0144] Table 5. Components of G1~G7 artificial lightweight aggregates

[0145]

[0146] Cube concrete specimens of the same grade were prepared using natural crushed stone coarse aggregate particles with the same particle shape coefficient and gradation as the control group M0, and the particle size of the natural crushed stone coarse aggregate was G0; cubic compressive strength tests were conducted on M0~M7 artificial lightweight aggregate concrete respectively.

[0147] When selecting raw materials to prepare concrete specimens, the mix proportions must ensure that all aggregates have the same volume. Therefore, each group includes the following raw materials by mass:

[0148] Table 6. Composition of C30 cubic concrete specimens

[0149]

[0150] First, weigh all the required raw materials as instructed.

[0151] Then, use a mixer to thoroughly mix all the ingredients until they are homogeneous;

[0152] Finally, a 150*150*150mm cubic mold was placed on a vibrating table and concrete slurry was poured in; after natural curing for 28 days, specimens were obtained and their compressive strength was tested. Figure 11 This is a schematic diagram showing the compressive strength results of a cubic concrete specimen. Figure 12In the middle (a) and (b), respectively, schematic diagrams of the compressive failure of M0 and M5 are shown;

[0153] Depend on Figure 11 It can be seen that the compressive strength of the natural crushed stone coarse aggregate 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. Figure 12 It is evident that the mortar phase inside M0 (marked with a red circle) is relatively loose, while the basalt fibers in M5 effectively improve the density of the mortar phase and the performance of the interfacial transition zone, inhibiting the development of microcracks, thereby enhancing the overall structural integrity and crack resistance. Furthermore, neither the natural crushed stone coarse aggregate particles nor the artificial lightweight aggregate G1 (coarse aggregate marked with a blue circle) showed significant breakage during the failure process. It was also observed that the artificial lightweight aggregate and the mortar were more uniformly and tightly bonded, without any obvious protrusion of the natural crushed stone coarse aggregate particles, demonstrating good load-bearing capacity. With the reduction in cement content and the increase in coal gangue particle content, the pore structure of the concrete was effectively improved in M4–M7, with compressive strengths reaching 32.14 MPa, 36.21 MPa, 34.21 MPa, and 35.70 MPa respectively, close to M0 and all meeting the requirements of the C30 strength grade. Figure 12 In Figure (b), it was observed that coal gangue particles played a positive role in filling pores and improving structural density. Simultaneously, basalt fibers encapsulating the aggregate surface significantly enhanced the bonding performance of the interfacial transition zone (ITZ), effectively inhibiting the propagation of microcracks. Furthermore, M4-M7 exhibited superior environmental performance while maintaining mechanical properties, demonstrating promising prospects for widespread application. Figure 12 It can also be seen that the failure mode of artificial lightweight aggregate concrete and natural crushed stone coarse aggregate particle concrete both exhibit typical "inverted cone" failure characteristics; the various properties of G3 artificial lightweight aggregate are weaker, resulting in a decrease in the compressive strength of M3.

[0154] Figures 3-11 The test results for the artificial lightweight aggregates in the example group are shown. With Example G1 as the control group, Examples G2 to G7 optimized the aggregate ratio while keeping the water-cement ratio constant, gradually reducing the amount of cement, increasing the amount of coal gangue particles and the replacement rate of cementitious materials, aiming to achieve low carbon and environmental protection while meeting the specifications.

[0155] Depend on Figure 3 , Figure 4 It can be seen that the bulk density of the G1~G7 artificial lightweight aggregate example groups is all between 800 and 900. The apparent density ranges from 1789.37 to 2047.23. It conforms to the 900 density grade lightweight coarse aggregate in Clause 5.2 of GB / T17431.1~2010 "Lightweight aggregates and their test methods Part 1: Lightweight aggregates";

[0156] Depend on 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, G2's water absorption rate decreased due to the addition of coal gangue particles, which reduced porosity; G3's water absorption rate increased significantly due to the addition of a large amount of waste glass, resulting in irregular particle size and increased porosity. G4–G7 effectively improved the pore structure by reducing the amount of cement and waste glass and increasing the substitution rate of cementitious materials, reducing the water absorption rate to 8.46%, 7.19%, 9.83%, and 9.65%, respectively, which is close to that of G1 and G2, demonstrating better green performance. Except for G3, all other groups meet the requirement of Clause 5.4.1 of GB / T 17431.1~2010, "Lightweight Aggregates and Their Test Methods Part 1: Lightweight Aggregates," that the water absorption rate of 900 density grade lightweight coarse aggregates should not exceed 10%.

[0157] Depend on Figure 6 The crushing values ​​of G1, G2, and G3 were 9.52%, 9.27%, and 15.18%, respectively. Among them, the crushing value of G2 decreased slightly with the addition of coal gangue particles. In group G3, due to the excessive amount of waste glass, the aggregate brittleness significantly increased, the compressive strength decreased, and it was prone to breakage under pressure. Groups G4-G7 achieved a relatively reasonable balance between lightweighting and mechanical properties by optimizing the amount of cement and waste glass and increasing the substitution rate of cementitious materials, although their crushing values ​​increased to 14.05%, 12.12%, 13.65%, and 13.62%, respectively. All experimental groups met the relevant requirements of the "Standard for Quality and Testing Methods of Sand for Ordinary Concrete". It is worth noting that the crushing value of artificial lightweight aggregates is generally positively correlated with their water absorption rate; that is, the lower the water absorption rate, the better the crushing resistance of the aggregate.

[0158] Figure 7 , Figure 8 The SEM micrographs of Examples 2 and 3 show that the hydration reaction inside the aggregate is relatively complete, and no large amount of calcium hydroxide (CH) crystals are observed to accumulate, 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 As shown in Figure (a), the main hydration product under water curing conditions is calcium silicate hydrate (C~S~H), which significantly fills the pores and enhances the stability of the matrix structure. In addition, the dense structure and rough surface of the matrix help to improve the bonding strength and overall compressive strength of the interfacial transition zone.

[0159] Figure 9 In (a), it can be clearly observed that a large number of needle-like AFt (ettringite) are generated on both the matrix and the surface of the basalt fibers. Figure 9(b) shows the staggered embedding distribution of basalt fibers in the matrix, effectively inhibiting the propagation of microcracks and improving the toughness and crack resistance of the composite material. Furthermore, the aggregates in the example group not only have basalt fibers embedded internally, but also have basalt fibers uniformly distributed on their outer surface, achieving comprehensive reinforcement from the aggregate core to the interface region. This distribution optimizes the interfacial transition zone between the concrete mortar and the aggregate, significantly improving the compressive strength of the concrete and exhibiting excellent comprehensive mechanical properties.

[0160] The present invention also provides the following embodiments for preparing coal-based multi-element solid waste artificial lightweight aggregate.

[0161] Example 9

[0162] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0163] The composition includes 6.190 kg fly ash, 1.032 kg cement, 3.766 kg water, 0.105 kg basalt fiber, 0.42 kg waste glass, 4.127 kg slag, 3.720 kg coal gangue, and 0.015 kg water-reducing agent.

[0164] This embodiment also includes a method for preparing the coal-based multi-element solid waste artificial lightweight aggregate, the steps of which are as follows:

[0165] Select natural crushed stone coarse aggregate particles of 10~15mm, 15~20mm, and 20~30mm, wash and dry them, and place them in container A for later use. Strictly mix silica gel A and silica gel B of type GH~636 at a mass ratio of 1:1, place them in container B, and stir with a mixer for 5 minutes until homogeneous.

[0166] Next, pour the mixed silica gel solution into container A containing natural crushed stone coarse aggregate particles, ensuring that the particles are completely covered by the silica gel solution. Let it stand for 3 hours until the silica gel solution solidifies, then remove the natural crushed stone coarse aggregate particles to obtain a mold for preparing aggregates; repeat this step to obtain the mold.

[0167] Coal gangue is crushed and screened in a crusher to obtain coal gangue particles with a particle size of less than 0.9 mm; coal gangue, slag, fly ash, cement, waste glass and basalt fiber are weighed in proportion;

[0168] Weigh out the water-reducing agent and water, mix them thoroughly, pour them into the raw materials, and mix them with a mixer. After mixing evenly, the pretreated material is obtained.

[0169] Pour the pre-treated material evenly into the mold. This operation should be carried out on a vibrating table to ensure that it is fully and evenly filled. Place the mold containing the pre-treated material in a flat, dry and ventilated place and cure for 3 days. Demold to obtain artificial lightweight aggregate. The 3-day curing treatment allows for more thorough contact between the materials and allows the slurry to solidify.

[0170] Collect the aggregate, place it in container C, pour in water to cover the surface, and cure for 28 days to obtain the finished aggregate product.

[0171] Example 10

[0172] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0173] The ingredients are: 6.0 kg fly ash, 1.0 kg cement, 3.6 kg water, 0.1 kg basalt fiber, 0.4 kg waste glass, 4.0 kg slag, 3.3 kg coal gangue, and 0.01 kg water-reducing agent.

[0174] This embodiment also includes a method for preparing the coal-based multi-element solid waste artificial lightweight aggregate, the steps of which are as follows:

[0175] Select natural crushed stone coarse aggregate particles of 10~15mm, 15~20mm, and 20~30mm, wash and dry them, and place them in container A for later use. Strictly mix silica gel A and silica gel B of type GH~636 at a mass ratio of 1:1, place them in container B, and stir with a mixer for 3 minutes until homogeneous.

[0176] Next, pour the mixed silica gel solution into container A containing natural crushed stone coarse aggregate particles, ensuring that the particles are completely covered by the silica gel solution. Let it stand for 3 hours until the silica gel solution solidifies, then remove the natural crushed stone coarse aggregate particles to obtain a mold for preparing aggregates; repeat this step to obtain the mold.

[0177] Coal gangue is crushed and screened in a crusher to obtain coal gangue particles with a particle size of less than 0.9 mm; coal gangue, slag, fly ash, cement, waste glass and basalt fiber are weighed in proportion;

[0178] Weigh out the water-reducing agent and water, mix them thoroughly, pour them into the raw materials, and mix them with a mixer. After mixing evenly, the pretreated material is obtained.

[0179] Pour the pre-treated material evenly into the mold. This operation should be carried out on a vibrating table to ensure that it is fully and evenly filled. Place the mold containing the pre-treated material in a flat, dry and ventilated place and cure for 3 days. Demold to obtain artificial lightweight aggregate. The 3-day curing treatment allows for more thorough contact between the materials and allows the slurry to solidify.

[0180] Collect the aggregate, place it in container C, pour in water to cover the surface, and cure for 28 days to obtain the finished aggregate product.

[0181] Figure 10 The XRD patterns of Examples 5, 6, and 7 show that all three aggregate groups contain quartz, calcite, ettringite, and carbonate minerals, with a reasonable overall mineral composition. The diffraction peaks are relatively densely distributed. Comparison reveals that the intensity of the calcite diffraction peak increases with the increase of coal gangue content, mainly because coal gangue contains crystalline quartz (SiO2), which is less likely to participate in hydration reactions. This type of aggregate with multiple coexisting minerals not only exhibits excellent mechanical properties but also helps improve the stability and durability of concrete, achieving a good balance between lightweighting and structural performance.

[0182] Example 11

[0183] A coal-based multi-element solid waste artificial lightweight aggregate comprises the following raw materials by weight:

[0184] The ingredients are: 4.65 kg fly ash, 5.2 kg cement, 3.8 kg water, 0.2 kg basalt fiber, 0.9 kg waste glass, 4.2 kg slag, 4.2 kg coal gangue, and 0.02 kg water-reducing agent.

[0185] This embodiment also includes a method for preparing the coal-based multi-element solid waste artificial lightweight aggregate, the steps of which are as follows:

[0186] Select natural crushed stone coarse aggregate particles of 10~20mm and 20~30mm, wash and dry them, and place them in container A for later use. Strictly mix silica gel A and silica gel B of type GH~636 at a mass ratio of 1:1, place them in container B, and stir with a mixer for 3 minutes until uniform.

[0187] Next, pour the mixed silica gel solution into container A containing natural crushed stone coarse aggregate particles, ensuring that the particles are completely covered by the silica gel solution. Let it stand for 3 hours until the silica gel solution solidifies, then remove the natural crushed stone coarse aggregate particles to obtain a mold for preparing aggregates; repeat this step to obtain the mold.

[0188] Coal gangue is crushed and screened in a crusher to obtain coal gangue particles with a particle size of less than 0.9 mm; coal gangue, slag, fly ash, cement, waste glass and basalt fiber are weighed in proportion;

[0189] Weigh out the water-reducing agent and water, mix them thoroughly, pour them into the raw materials, and mix them with a mixer. After mixing evenly, the pretreated material is obtained.

[0190] Pour the pre-treated material evenly into the mold. This operation should be carried out on a vibrating table to ensure that it is fully and evenly filled. Place the mold containing the pre-treated material in a flat, dry and ventilated place and cure for 3 days. Demold to obtain artificial lightweight aggregate. The 3-day curing treatment allows for more thorough contact between the materials and allows the slurry to solidify.

[0191] Collect the aggregate, place it in container C, pour in water to cover the surface, and cure for 28 days to obtain the finished aggregate product.

[0192] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing coal-based multi-element solid waste artificial lightweight aggregate, characterized in that, Includes the following steps: Natural crushed stone coarse aggregate particles are selected and graded to form a coarse aggregate aggregate; the shape coefficient of the natural crushed stone coarse aggregate particles is 0.65~0.95; the coarse aggregate aggregate is composed of natural crushed stone coarse aggregate particles with particle sizes of 10~15mm, 15~20mm and 20~30mm. After cleaning the coarse aggregate, it is immersed in the silica gel mixture. After the silica gel mixture solidifies, the natural crushed stone coarse aggregate particles are removed to obtain a mold for preparing aggregate. Fly ash, cement, and basalt fiber are added to crushed coal gangue; then a mixture of water-reducing agent and water is added and stirred evenly to obtain pretreated material; the mass ratio of coal gangue, fly ash, cement, basalt fiber, water-reducing agent, 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); the particle size of the coal gangue is less than 0.9 mm; The pretreated material is poured into the mold and cured naturally once. After the pretreated material solidifies, it is demolded to obtain artificial lightweight aggregate. After the artificial lightweight aggregate is cured naturally a second time, the finished product of coal-based multi-element solid waste artificial lightweight aggregate is obtained. The addition of basalt fiber causes the basalt fiber filaments to adhere to the interface transition zone of the finished coal-based multi-element solid waste artificial lightweight aggregate. The basalt fiber is interwoven and distributed in the matrix, and the basalt fiber filaments attached to the surface form a network structure in the mortar interface transition zone.

2. The method for preparing coal-based multi-element solid waste artificial lightweight aggregate according to claim 1, characterized in that, The curing conditions for the silicone mixture are: natural air drying at 15~25℃ for 3~5 hours.

3. The method for preparing coal-based multi-element solid waste artificial lightweight aggregate according to claim 1, characterized in that, The process involves adding fly ash, cement, basalt fiber, slag, and waste glass to the crushed coal gangue. The mass ratio of coal gangue to slag and waste glass is (3.3~4.2):(4.0~5.7):(0.42~4.2).

4. The method for preparing coal-based multi-element solid waste artificial lightweight aggregate according to claim 1, characterized in that, The first natural curing period lasts for 3 days; the second natural curing period lasts for 28 days.

5. A coal-based multi-element solid waste artificial lightweight aggregate, characterized in that, It is prepared by the method of any one of claims 1 to 4 for the preparation of coal-based multi-element solid waste artificial lightweight aggregate.

6. The coal-based multi-element solid waste artificial lightweight aggregate according to claim 5, characterized in that, The water absorption rate of the coal-based multi-element solid waste artificial lightweight aggregate is 7.19%~11.56%; the apparent density is 1789.37~2047.23 kg / cm³. 3 The bulk density is 793.11~848.36 kg / cm³. 3 The crushing value ranges from 9.27% ​​to 15.18%.

7. The application of the coal-based multi-element solid waste artificial lightweight aggregate as described in claim 6 in the preparation of building materials.

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