Method for preparing light high-strength ceramic by using compound coal-based solid waste

Abstract

The present application provides a kind of method for preparing light high-strength ceramic by compounding coal-based solid waste, the present application takes coal gangue, fly ash as main material, yellow clay as auxiliary material, according to weight percentage: coal gangue 50%~60%, fly ash 20%, yellow clay 20%~30%. The method adds yellow clay on the basis of traditional coal gangue fly ash ceramic, and improves the performance of the compounding coal-based solid waste ceramic by increasing viscosity. The present application has simple production process, high cost rate, absorbs a large amount of coal-based solid waste, and improves the utilization rate of coal-based solid waste. The ceramic has low bulk density, high cylinder pressure strength, strong water absorption, solves the problem of waste resource waste, reduces environmental pollution at the same time, helps to protect the ecological environment of coal production area.

Description

Technical Field

[0001] This invention relates to the field of ceramsite preparation, and more specifically to a method for preparing ceramsite based on coal gangue, fly ash, and yellow mud. Background Technology

[0002] Coal gangue is carbonaceous rock discharged during coal mine construction, mining, and washing processes. It is a byproduct of coal mine production, accounting for approximately 15% to 20% of total coal output. Its main mineral components include kaolin, quartz, montmorillonite, feldspar, illite, calcite, and pyrite. Kaolin is present in high amounts and can be used to prepare ceramics and refractory materials, making it an important component for the resource utilization of coal gangue. The hazards of coal gangue include: firstly, its accumulation occupies large amounts of land, forming gangue mountains. Statistics show that my country's annual coal gangue discharge is approximately 300 to 350 million tons, resulting in numerous gangue mountains. These mountains not only occupy valuable land for agriculture or other construction purposes but also potentially lead to vegetation destruction and ecosystem imbalance. On the other hand, coal gangue causes environmental pollution: During the stockpiling process, coal gangue generates dust containing large amounts of particulate matter such as SiO2 and Al2O3. These particles are dispersed by the wind, polluting the atmosphere and affecting air quality and human health. In addition, spontaneous combustion of coal gangue piles is also common. This is because the coal in the gangue undergoes an oxidation reaction under certain conditions, releasing large amounts of harmful gases that threaten the atmospheric environment and the health of nearby residents. As a solid waste generated during coal mining and washing, the large-scale accumulation of coal gangue not only occupies land resources but also negatively impacts the surrounding ecological environment. How to effectively utilize coal gangue has become a crucial issue that the industry urgently needs to address.

[0003] Fly ash is a solid waste emitted by coal-fired power plants. It consists of fine ash particles collected by dust removal systems after combustion in coal-fired boilers at high temperatures of 1300-1500℃. Its chemical composition is mainly SiO2 (40%-60%) and Al2O3 (20%-30%), while also containing Fe2O3, CaO, and other components, exhibiting pozzolanic activity. As an important industrial solid waste resource, fly ash is most widely used in the building materials industry: it can replace 30%-50% of cement in concrete preparation, reducing heat of hydration and improving durability; it can reduce the weight of aerated concrete blocks by 30%; and it can reduce carbon emissions by 70% compared to traditional cement in the preparation of geopolymer cementitious materials. In the environmental protection field, surface modification can produce adsorbent materials to treat heavy metal wastewater; in agriculture, applying 2-4 tons / hectare of magnetized fly ash can increase soil porosity by 15% and increase crop yield by 8%-12%. Global annual production exceeds 1 billion tons, with my country accounting for over 65%. Large-scale utilization not only conserves natural resources but also avoids the land occupation and heavy metal pollution risks associated with landfilling, aligning with the concept of "zero-waste cities." Current key research areas include ultrafine powder modification, rare element extraction, and the development of high-dosage application technologies, driving its upgrading towards high-value-added fields.

[0004] Yellow clay is a common natural clay found in the surface layer of the earth. Rich in minerals such as iron oxide, it appears yellow or yellowish-brown and is widely distributed in hilly areas, riverbanks, and plains. Its fine texture, combined with its stickiness, plasticity, and breathability, makes it a core material in traditional architecture. For example, in southern China, rammed earth walls and adobe houses utilize yellow clay mixed with straw or sand, compacted to form sturdy walls with excellent thermal insulation properties. In northern cave dwellings, yellow clay is directly used for roofing to regulate indoor humidity. Furthermore, yellow clay is often used to make coarse pottery, earthenware pots, and other everyday utensils, retaining their rustic texture after low-temperature firing. In agricultural production, yellow clay can improve sandy soil and enhance its water and fertilizer retention capacity; however, its heavy, sticky nature necessitates mixing it with sand to prevent compaction that could hinder crop root growth.

[0005] Expanded clay aggregate (ECA) is a type of lightweight, man-made aggregate made from specific raw materials through a granulation process to form spherical or near-spherical particles of a certain size. These particles are then sintered at high temperatures or cured using other methods, resulting in an aggregate with a dense, porous internal structure. It is typically round or elliptical in shape. Due to its lightweight, high strength, excellent thermal insulation, sound absorption, good chemical stability, and strong fire resistance, EC is widely used in concrete production, thermal insulation, sound absorption and noise reduction, flower cultivation, hydroponics, wastewater treatment, and underground backfilling. Traditionally, EC uses natural resources such as clay, shale, and zeolite as raw materials, which has caused some damage to the local ecological environment. Therefore, exploring new avenues to find alternative resources to replace clay and shale has become a current research focus. Summary of the Invention

[0006] The purpose of this invention is to provide a lightweight, high-strength ceramsite made from boron mud and its preparation method, so as to solve the problems existing in the above-mentioned background art.

[0007] The technical solution of this invention is implemented as follows: A method for preparing lightweight, high-strength ceramsite using compounded coal-based solid waste, the specific process steps of which are as follows: Step 1: Use a crusher to crush the coal gangue into coarse aggregate; Step 2: Raw material grinding. The crushed mixture is fed into a grinding mill for grinding. Step 3: Weigh a certain amount of coal gangue, fly ash, and fine yellow mud from Step 2, and water accounting for 15% to 18% of the total mass; Step 4: Granulation. First, put the dry material into the granulator, mix it thoroughly and evenly, then add water in small amounts several times to form the material into spheres. Step 5: Sift to remove raw pottery with a diameter of 5-10mm; Step 6: The raw material balls are conveyed directly to the rotary kiln via a belt conveyor for roasting. The roasting time in the roasting section is 10-15 minutes and the temperature is 1050-1150℃. After roasting, the balls are placed in a cooling kiln for heat preservation and cooling.

[0008] Compared with existing technologies, the beneficial effects of this invention are as follows: The coal gangue and fly ash in the raw materials for ceramsite production are solid wastes. Compared with ceramsite made solely from coal gangue, this effectively solves the problems of surface pollution and land waste caused by fly ash accumulation, and can effectively realize the resource utilization of waste. Ceramsite raw materials do not use shale and yellow clay resources, which can effectively protect the ecological environment. The method for preparing ceramsite is simple in formulation, has low raw material costs, and produces ceramsite with good performance. Attached Figure Description

[0009] Figure 1 This is a flowchart of the process flow of the present invention. Detailed Implementation

[0010] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0011] Example 1 A method for preparing lightweight, high-strength ceramsite using compounded coal-based solid waste, the specific process steps of which are as follows: Step 1: Use a crusher to crush the coal gangue into coarse aggregate; Step 2: Raw material grinding. The crushed mixture is fed into a grinding mill for grinding. Step 3: Weigh out a certain amount of the coal gangue (70%), fly ash (20%), yellow mud (10%), and water (15% to 18% of the total mass) from Step 2; Step 4: Granulation. First, put the dry material into the granulator, mix it thoroughly and evenly, then add water in small amounts several times to form the material into spheres. Step 5: Sift to remove raw pottery with a diameter of 5-10mm; Step 6: The raw material balls are conveyed directly to the rotary kiln via a belt conveyor for roasting. The roasting time in the roasting section is 15 minutes and the temperature is 1050℃. After roasting, the balls are placed in a cooling kiln for heat preservation and cooling.

[0012] The prepared ceramsite has a density grade of 900, a bulk density of 858 kg / m3, a cylinder compressive strength of 32 MPa, and a water absorption rate of 15.8% after 2 hours.

[0013] Example 2 A method for preparing lightweight, high-strength ceramsite using compounded coal-based solid waste, the specific process steps of which are as follows: Step 1: Use a crusher to crush the coal gangue into coarse aggregate; Step 2: Raw material grinding. The crushed mixture is fed into a grinding mill for grinding. Step 3: Weigh out a certain amount of the coal gangue (60%), fly ash (20%), yellow mud (20%), and water (15% to 18% of the total mass) from Step 2; Step 4: Granulation. First, put the dry material into the granulator, mix it thoroughly and evenly, then add water in small amounts several times to form the material into spheres. Step 5: Sift to remove raw pottery with a diameter of 5-10mm; Step 6: The raw material balls are conveyed directly to the rotary kiln via a belt conveyor for roasting. The roasting time in the roasting section is 15 minutes and the temperature is 1050℃. After roasting, the balls are placed in a cooling kiln for heat preservation and cooling.

[0014] The prepared ceramsite has a density grade of 900, a bulk density of 860 kg / m3, a cylinder compressive strength of 40 MPa, and a water absorption rate of 15.4% after 2 hours.

[0015] Example 3 A method for preparing lightweight, high-strength ceramsite using compounded coal-based solid waste, the specific process steps of which are as follows: Step 1: Use a crusher to crush the coal gangue into coarse aggregate; Step 2: Raw material grinding. The crushed mixture is fed into a grinding mill for grinding. Step 3: Weigh out a certain amount of the coal gangue (50%), fly ash (20%), yellow mud (30%), and water (15% to 18% of the total mass) from Step 2; Step 4: Granulation. First, put the dry material into the granulator, mix it thoroughly and evenly, then add water in small amounts several times to form the material into spheres. Step 5: Sift to remove raw pottery with a diameter of 5-10mm; Step 6: The raw material balls are conveyed directly to the rotary kiln via a belt conveyor for roasting. The roasting time in the roasting section is 10-15 minutes and the temperature is 1050℃. After roasting, the balls are placed in a cooling kiln for heat preservation and cooling.

[0016] The prepared ceramsite has a density grade of 900 and a bulk density of 699 kg / m³. 3 The cylinder compressive strength is 22 MPa, and the water absorption rate after 2 hours is 17.4%.

Claims

1. A method for preparing lightweight, high-strength ceramsite using compounded coal-based solid waste, characterized in that: The raw materials for the compound ceramsite are as follows by weight percentage: 50%–70% coal gangue, 20% fly ash, and 10%–30% yellow clay.

2. The lightweight, high-strength ceramsite prepared from compounded coal-based solid waste according to claim 1, characterized in that, The coal gangue has a SiO2 content of 50% to 55% and an Al2O3 content of 15% to 20%.

3. The lightweight, high-strength ceramsite prepared from compound coal-based solid waste according to claim 1, characterized in that, The fly ash has a SiO2 content of 55% to 60% and an Al2O3 content of 35% to 40%.

4. The method for preparing lightweight, high-strength ceramsite using compounded coal-based solid waste according to claim 1, characterized in that: The sintering temperature of the ceramsite is 1050℃~1150℃, and the sintering time is 10 min~15 min.

5. A method for preparing coal gangue ceramsite, characterized in that: The specific preparation steps are as follows: Step 1: Use a crusher to crush the coal gangue into coarse aggregate; Step 2: Raw material grinding. The crushed mixture is fed into a grinding mill for grinding. Step 3: Weigh a certain amount of coal gangue, fly ash, and fine yellow mud from Step 2, and water accounting for 15% to 18% of the total mass; Step 4: Granulation. First, put the dry material into the granulator, mix it thoroughly and evenly, then add water in small amounts several times to form the material into spheres. Step 5: Sift to remove raw pottery with a diameter of 5-10mm; Step 6: The raw material pellets are conveyed directly to the rotary kiln via a belt conveyor for roasting. The roasting time in the roasting section is 10-15 minutes and the temperature is 1050-1150℃. After roasting, the pellets are placed in a cooling kiln for heat preservation and cooling, and finally stored in the warehouse.

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