Method for preparing low-carbon cementing material from industrial solid waste

Abstract

The invention provides a method for preparing a low-carbon cementing material from industrial solid waste, and relates to the technical field of low-carbon cementing materials, the method comprises the following steps: S1, thermal activation: mixing steel slag, mineral slag, desulfurized gypsum and red mud, and carrying out thermal treatment at 400-800 DEG C for 50-70 min to obtain a first mixture; s2, mechanical activation: grinding the first mixture until the particle size is 0.1-10 [mu] m to obtain a second mixture; and S3, chemical excitation: adding a chemical exciting agent into the second mixture. The method can improve the utilization efficiency of solid waste, remarkably reduces carbon emission, and conforms to the concept of green sustainable development.

Description

Technical Field

[0001] The invention relates to the technical field of low-carbon gelling materials, in particular to a method for preparing low-carbon gelling materials by utilizing industrial solid waste. Background Art

[0002] With the advancement of industrialization, a large amount of solid waste, such as steel slag, slag, desulfurized gypsum and red mud, has been generated in industrial fields such as steel, smelting and thermal power. The disorderly accumulation of these industrial solid wastes occupies a large amount of land resources, including potential hazards to soil, groundwater and atmosphere. Therefore, how to effectively treat and efficiently utilize these solid waste resources has become a key issue of concern in modern society.

[0003] In recent years, more and more researchers have begun to explore the use of industrial solid waste in the production of building materials, especially to replace traditional cementitious materials. The traditional cement production process produces a large amount of carbon dioxide, and the use of industrial solid waste to produce cementitious materials can not only reduce carbon emissions, but also effectively digest solid waste resources, with significant environmental benefits. However, due to the large differences in the physical and chemical properties of different industrial solid wastes, how to improve their activity through reasonable processes and ensure the stability of material properties remains a technical challenge. Summary of the invention

[0004] In view of the above-mentioned prior art, the present invention proposes a method for preparing low-carbon cementitious materials by utilizing industrial solid waste.

[0005] The present invention provides a method for preparing a low-carbon cementitious material using industrial solid waste, comprising the following steps: S1. Thermal activation: mixing steel slag, slag, desulfurized gypsum and red mud, and heat treating at 400-800° C. for 50-70 min to obtain a first mixture; Among them, the glassy structure in steel slag and slag will gradually disintegrate at higher temperatures, releasing reactive silicate and aluminate components. Desulfurized gypsum will undergo a dehydration reaction at 400-800°C, gradually transforming from dihydrate gypsum to hemihydrate gypsum and anhydrous gypsum, thereby enhancing its chemical reactivity. The iron oxides and aluminum oxides in red mud do not undergo significant structural changes at high temperatures, but their moisture and some organic impurities can be removed, improving their stability as auxiliary materials. Therefore, within the range of 400-800°C, the active components in the solid waste are gradually stimulated, and the high temperature causes the glassy structure to break, while reducing the impurity content in the material. Higher temperatures not only help to increase the reactivity of solid waste, but also reduce the inherent defects of the material, allowing it to exhibit higher hydration potential in subsequent reactions.

[0006] S2, mechanical activation: grinding the first mixture to a particle size of 0.1-10 μm to obtain a second mixture; Among them, through the ball milling process, the specific surface area of ​​the material particles is significantly increased, which helps to enhance the reaction efficiency in the subsequent chemical excitation stage. The grinding process can also introduce surface defects of the particles, such as dislocations and vacancies, which can serve as active sites for chemical reactions, further improving the reactivity of the material. Therefore, mechanical activation increases the specific surface area by refining the particle size, increases the contact surface between the solid waste and other reaction components, and the introduced crystal defects also help accelerate the hydration reaction. Micron to submicron particle sizes can provide an ideal physical basis for subsequent chemical excitation.

[0007] S3, chemical excitation: adding a chemical excitation agent to the second mixture; Among them, chemical activators can effectively increase the activity of aluminates and silicates in slag and steel slag, and promote hydration reactions to generate CSH gel. Alkaline environments can also further promote the reactivity of desulfurized gypsum and red mud, increasing the early strength and long-term durability of the material.

[0008] Preferably, in S2, in the grinding process, the ball-to-material ratio is 10:1, and the grinding time is 2-4 hours.

[0009] Preferably, in S3, the chemical activator is an alkaline solution or a silicate compound. The alkaline activator provides a high pH environment, effectively enhancing the reactivity of aluminates and silicates in steel slag and slag, so that the reaction generates a hydration product with good gelling properties. The introduction of compounds such as sodium silicate can enhance the long-term stability of the material.

[0010] Preferably, in S3, the concentration of the chemical stimulant is 3-5%.

[0011] Preferably, in S3, the amount of the chemical stimulant added is 5-10% by weight of the second mixture.

[0012] Preferably, the equipment used includes a continuous heat treatment furnace, the inlet of the continuous heat treatment furnace is connected to the outlet of the solid waste raw material tank, the inlet of the solid waste raw material tank is connected to the feed pipe, the outlet of the continuous heat treatment furnace is connected to the inlet of a high-energy ball mill, the outlet of the high-energy ball mill is connected to the inlet of a metering mixer, and the outlet of the metering mixer is connected to the inlet of a finished material storage tank.

[0013] The continuous heat treatment furnace can perform constant temperature heat treatment on solid waste within the range of 400-800°C and has an automatic temperature control function. The furnace is equipped with a material conveying device to ensure that the material is evenly heated throughout the process to prevent local overheating or temperature fluctuations. The continuous heat treatment furnace can achieve continuous production, effectively improve production efficiency and reduce energy consumption. In addition, the precise temperature control function ensures that different types of solid waste are treated within the optimal temperature range.

[0014] The high-energy ball mill is used in the mechanical activation stage, with high grinding efficiency and good stability. The high-energy ball mill is equipped with a long-term operation and temperature control device to ensure that the material does not overheat or over-grind during the grinding process. High-energy ball milling technology can refine material particles to micron or even submicron level while reducing mechanical energy consumption. Through reasonable ball milling parameter setting, the particle size and surface activity of the particles can be accurately controlled.

[0015] The metering mixer can accurately measure the amount of various raw materials and chemical stimulants added, with the metering accuracy controlled within ±0.1%, and ensure the full mixing of materials and stimulants through the stirring system. The metering mixer adopts high-speed stirring method, which can evenly distribute the active ingredients and ensure the adequacy of the reaction. The metering mixer can not only ensure the accurate ratio of each raw material, but also improve the uniformity and quality stability of the material by optimizing the stirring process.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention proposes a method for preparing low-carbon cementitious materials from industrial solid wastes. The method uses a three-stage activity enhancement mechanism of thermal activation, mechanical activation and chemical excitation to synergistically utilize industrial solid wastes such as steel slag, slag, desulfurized gypsum and red mud to prepare low-carbon cementitious materials with excellent performance. The present invention not only improves the utilization efficiency of solid wastes, but also significantly reduces carbon emissions, which is in line with the concept of green and sustainable development.

[0017] 2. The present invention has the following advantages: 1) Excellent mechanical properties: The material of the present invention has high compressive strength and flexural strength, which can meet the mechanical performance requirements in construction projects. 2) Good durability: The present invention exhibits excellent resistance to chemical corrosion and freeze-thaw resistance, and is suitable for use in harsh environments. 3) Low carbon and environmental protection: The production process of the present invention utilizes a large amount of industrial solid waste, reduces dependence on natural resources, and reduces carbon emissions, which is in line with the current development trend of green building materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the results of the equipment used in the method for preparing low-carbon cementitious materials using industrial solid waste in an embodiment of the present invention.

[0019] Among them, 1. Solid waste raw material tank; 2. Feed pipe; 3. Continuous heat treatment furnace; 4. High-energy ball mill; 5. Metering mixer; 6. Finished material storage tank. DETAILED DESCRIPTION

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0021] Example 1: A method for preparing low-carbon cementitious materials using industrial solid waste, such as Figure 1 As shown, the equipment used includes a continuous heat treatment furnace 3, the inlet of the continuous heat treatment furnace 3 is connected to the outlet of the solid waste raw material tank 1, the inlet of the solid waste raw material tank 1 is connected to the feed pipe 2, the outlet of the continuous heat treatment furnace 3 is connected to the inlet of the high-energy ball mill 4, the outlet of the high-energy ball mill 4 is connected to the inlet of the metering mixer 5, and the outlet of the metering mixer 5 is connected to the inlet of the finished material storage tank 6.

[0022] The method comprises the following steps: S1, thermal activation: 40% of steel slag, 30% of slag, 20% of desulfurized gypsum and 10% of red mud are mixed in a solid waste raw material tank 1 according to weight percentage, and then sent into a continuous heat treatment furnace 3, and heat treated at 600° C. for 60 minutes to obtain a first mixture; S2, mechanical activation: the first mixture is sent to a high-energy ball mill 4 for grinding, with a ball-to-material ratio of 10:1 and a grinding time of 3 hours, and the mixture is ground to a particle size of 5 μm to obtain a second mixture; S3, chemical excitation: feeding the second mixture into a metering mixer 5, adding a chemical excitation agent, wherein the chemical excitation agent is a sodium hydroxide solution, the concentration of the chemical excitation agent is 4%, and the amount of the chemical excitation agent added is 7% of the weight of the second mixture, to obtain a slurry; S4, molding and curing: injecting the slurry into a mold and curing it naturally at room temperature for 48 hours to obtain a high-performance low-carbon cementitious material product.

[0023] Example 2: A method for preparing low-carbon cementitious materials using industrial solid waste, such as Figure 1 As shown, the equipment used includes a continuous heat treatment furnace 3, the inlet of the continuous heat treatment furnace 3 is connected to the outlet of the solid waste raw material tank 1, the inlet of the solid waste raw material tank 1 is connected to the feed pipe 2, the outlet of the continuous heat treatment furnace 3 is connected to the inlet of the high-energy ball mill 4, the outlet of the high-energy ball mill 4 is connected to the inlet of the metering mixer 5, and the outlet of the metering mixer 5 is connected to the inlet of the finished material storage tank 6.

[0024] The method comprises the following steps: S1, thermal activation: 40% of steel slag, 30% of slag, 20% of desulfurized gypsum and 10% of red mud are mixed in a solid waste raw material tank 1 according to weight percentage, and then sent into a continuous heat treatment furnace 3, and heat treated at 400° C. for 70 minutes to obtain a first mixture; S2, mechanical activation: the first mixture is sent to a high-energy ball mill 4 for grinding, with a ball-to-material ratio of 10:1 and a grinding time of 2 hours, and the mixture is ground to a particle size of 10 μm to obtain a second mixture; S3, chemical excitation: feeding the second mixture into a metering mixer 5, adding a chemical excitation agent, wherein the chemical excitation agent is a calcium hydroxide solution, the concentration of the chemical excitation agent is 3%, and the amount of the chemical excitation agent added is 10% of the weight of the second mixture, to obtain a slurry; S4, molding and curing: injecting the slurry into a mold and curing it naturally at room temperature for 48 hours to obtain a high-performance low-carbon cementitious material product.

[0025] Example 3: A method for preparing low-carbon cementitious materials using industrial solid waste, such as Figure 1 As shown, the equipment used includes a continuous heat treatment furnace 3, the inlet of the continuous heat treatment furnace 3 is connected to the outlet of the solid waste raw material tank 1, the inlet of the solid waste raw material tank 1 is connected to the feed pipe 2, the outlet of the continuous heat treatment furnace 3 is connected to the inlet of the high-energy ball mill 4, the outlet of the high-energy ball mill 4 is connected to the inlet of the metering mixer 5, and the outlet of the metering mixer 5 is connected to the inlet of the finished material storage tank 6.

[0026] The method comprises the following steps: S1, thermal activation: 40% of steel slag, 30% of slag, 20% of desulfurized gypsum and 10% of red mud are mixed in a solid waste raw material tank 1 according to weight percentage, and then sent into a continuous heat treatment furnace 3, and heat treated at 800° C. for 50 minutes to obtain a first mixture; S2, mechanical activation: the first mixture is sent to a high-energy ball mill 4 for grinding, with a ball-to-material ratio of 10:1 and a grinding time of 4 hours, and the mixture is ground to a particle size of 0.1 μm to obtain a second mixture; S3, chemical excitation: feeding the second mixture into the metering mixer 5, adding a chemical excitation agent, wherein the chemical excitation agent is a sodium silicate solution, the concentration of the chemical excitation agent is 5%, and the amount of the chemical excitation agent added is 5% of the weight of the second mixture, to obtain a slurry; S4, molding and curing: injecting the slurry into a mold and curing it naturally at room temperature for 48 hours to obtain a high-performance low-carbon cementitious material product.

[0027] The above are only implementation modes of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent schemes made using the contents of the present invention specification, directly or indirectly applied in other related technical fields, are also within the patent protection scope of the present invention.

Claims

1. A method for preparing low-carbon cementitious materials using industrial solid waste, characterized in that: The steps include: S1. Thermal activation: mixing steel slag, slag, desulfurized gypsum and red mud, and heat treating at 400-800° C. for 50-70 min to obtain a first mixture; S2, mechanical activation: grinding the first mixture to a particle size of 0.1-10 μm to obtain a second mixture; S3, chemical excitation: adding a chemical excitation agent to the second mixture.

2. The method for preparing low-carbon cementitious materials using industrial solid waste according to claim 1, characterized in that: In S2, in the grinding process, the ball-to-material ratio is 10:1, and the grinding time is 2-4 hours.

3. The method for preparing low-carbon cementitious materials using industrial solid waste according to claim 1 or 2, characterized in that: In S3, the chemical activator is an alkaline solution or a silicate compound.

4. The method for preparing low-carbon cementitious materials using industrial solid waste according to claim 1 or 2, characterized in that: In S3, the concentration of the chemical stimulant is 3-5%.

5. The method for preparing low-carbon cementitious materials using industrial solid waste according to claim 1 or 2, characterized in that: In S3, the amount of the chemical stimulant added is 5-10% by weight of the second mixture.

6. The method for preparing low-carbon cementitious materials using industrial solid waste according to claim 1 or 2, characterized in that: The equipment used includes a continuous heat treatment furnace, the inlet of the continuous heat treatment furnace is connected to the outlet of the solid waste raw material tank, the inlet of the solid waste raw material tank is connected to the feed pipe, the outlet of the continuous heat treatment furnace is connected to the inlet of a high-energy ball mill, the outlet of the high-energy ball mill is connected to the inlet of a metering mixer, and the outlet of the metering mixer is connected to the inlet of a finished material storage tank.

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