Red-mud-based unfired prefabricated part and preparation method thereof
By preparing red mud-based non-fired precast components, and using a specific combination of raw materials to activate fluorite and gypsum to form cementitious products, the environmental pollution and resource waste caused by improper red mud treatment are solved, realizing the resource utilization of red mud and the improvement of the mechanical properties of precast components.
Patent Information
- Application Number
- CN202511395743.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-28
- Publication Date
- 2025-12-16
AI Technical Summary
Improper treatment of red mud in existing technologies leads to environmental pollution and resource waste, making it difficult to use it as a primary material in building materials.
The preparation method of red mud-based non-fired precast components involves a combination of red mud, fly ash, quartz sand, fluorite, desulfurized gypsum, silicate cement, quicklime, water-reducing agent, retarder, expanding agent, and fiber in a specific ratio. This activates the activating effect of fluorite and gypsum, forming cementitious products and enhancing the mechanical properties of the precast components.
This approach enables the resource utilization of red mud, improves the mechanical properties and environmental friendliness of precast components, and solves the environmental problems caused by red mud accumulation.
Smart Images
Figure BDA0005617650400000061
Abstract
Description
Technical Field
[0001] This invention relates to the field of solid waste resource technology, and in particular to a red mud-based non-fired precast component and its preparation method. Background Technology
[0002] Red mud is a byproduct of the aluminum industry, a polluting waste residue discharged during alumina extraction. Currently, there are no effective methods for treating red mud. Some manufacturers discharge it into the sea, polluting the marine environment and harming fisheries; others directly dump it in the open, allowing harmful substances to seep into the soil, occupying farmland and polluting groundwater, posing a drinking water safety risk. Furthermore, dried red mud is blown by the wind, polluting the atmosphere and directly impacting health. Adding red mud to building materials in excessive amounts fails to meet usage standards. Therefore, finding a suitable method to utilize red mud as a primary material to effectively dispose of the large quantities of accumulated red mud has become an urgent problem to solve. Summary of the Invention
[0003] The purpose of this invention is to overcome the problems in the prior art and provide a red mud-based non-fired preform and its preparation method.
[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0005] This invention provides a red mud-based non-fired precast component, prepared from raw materials comprising the following parts by weight:
[0006] Red mud 30-35 parts, fly ash 15-20 parts, quartz sand 20-30 parts, fluorite 5-8 parts, desulfurized gypsum 5-15 parts, silicate cement 5-8 parts, quicklime 1-3 parts, water-reducing agent 0.1-1 parts, retarder 0.5-1 parts, expansion agent 2-3 parts, fiber 1-2 parts, water 10-12 parts.
[0007] Preferably, the quartz sand comprises quartz sand with a particle size of 0.6 to 1.5 mm and quartz sand with a particle size of 0.2 to 0.5 mm;
[0008] The mass ratio of the quartz sand with a particle size of 0.6 to 1.5 mm to the quartz sand with a particle size of 0.2 to 0.5 mm is 1:1 to 1.25.
[0009] Preferably, the fluorite has a particle size ≥ 200 mesh, and the desulfurized gypsum has a particle size of 200-300 mesh.
[0010] Preferably, the water-reducing agent is a naphthalene-based water-reducing agent and / or a polycarboxylate water-reducing agent;
[0011] The retarder is sodium gluconate and / or citric acid.
[0012] Preferably, the expanding agent is a UEA expanding agent;
[0013] The fiber is polypropylene fiber or glass fiber;
[0014] The fiber has a length of 10–16 mm and a diameter of 20–50 μm.
[0015] The present invention also provides a method for preparing the red mud-based non-fired precast component, comprising the following steps:
[0016] (1) Dry mix red mud, fly ash, fluorite, desulfurized gypsum, quartz sand, silicate cement and quicklime, and then add the remaining raw materials and mix to obtain a mixture;
[0017] (2) Press the mixture into a blank;
[0018] (3) Curing the blanks yields the red mud-based non-fired precast parts.
[0019] Preferably, the dry mixing speed in step (1) is 80-150 rpm and the time is 20-30 min.
[0020] Preferably, the stirring speed in step (1) is 200-400 rpm and the stirring time is 10-20 min.
[0021] Preferably, the pressing pressure in step (2) is 30-40 MPa and the holding time is 1-2 min.
[0022] Preferably, the curing temperature in step (3) is 20-40℃, the humidity is ≥80%, and the curing time is 7-15 days.
[0023] This invention provides a red mud-based non-fired precast component, prepared from raw materials comprising the following parts by weight: 30-35 parts red mud, 15-20 parts fly ash, 20-30 parts quartz sand, 5-8 parts fluorite, 5-15 parts desulfurized gypsum, 5-8 parts silicate cement, 1-3 parts quicklime, 0.1-1 parts water-reducing agent, 0.5-1 parts retarder, 2-3 parts expanding agent, 1-2 parts fiber, and 10-12 parts water. In this invention, quicklime provides an alkaline environment, activating the activating effects of fluorite and gypsum under high alkalinity. The fluorine in fluorite strongly breaks down the vitreous structure of red mud and fly ash, releasing active silica and alumina components. Meanwhile, sulfate ions in gypsum combine with active aluminum ions to form ettringite, improving the early strength of the precast component. The dissolved active components react with calcium and fluoride ions to generate CSH gel, hydrated calcium fluoroaluminate, and other cementing products, which, together with ettringite, contribute to the overall strength. The resulting gelled product, used as an adhesive, binds quartz sand with other solid particles and fibers, forming a disordered structure that increases tensile strength and improves the product's mechanical properties. Simultaneously, retarders and expanding agents are added to effectively slow down the initial gelation rate of the product, preventing problems such as cracking. This invention utilizes a systematic physical and chemical process to apply red mud to precast components, achieving waste recycling. Detailed Implementation
[0024] This invention provides a red mud-based non-fired precast component, prepared from raw materials comprising the following parts by weight:
[0025] Red mud 30-35 parts, fly ash 15-20 parts, quartz sand 20-30 parts, fluorite 5-8 parts, desulfurized gypsum 5-15 parts, silicate cement 5-8 parts, quicklime 1-3 parts, water-reducing agent 0.1-1 parts, retarder 0.5-1 parts, expansion agent 2-3 parts, fiber 1-2 parts, water 10-12 parts.
[0026] In this invention, the mass fraction of red mud is preferably 31 to 34 parts, more preferably 32 to 33 parts, and even more preferably 32.5 to 32.8 parts.
[0027] In this invention, the mass fraction of fly ash is preferably 15.5 to 19.5 parts, more preferably 16 to 19 parts, and even more preferably 17 to 18 parts.
[0028] In this invention, the mass fraction of quartz sand is preferably 21 to 29 parts, more preferably 22 to 28 parts, and even more preferably 24 to 26 parts.
[0029] In this invention, the mass fraction of fluorite is preferably 5.5 to 7.5 parts, more preferably 6 to 7 parts, and even more preferably 6.5 to 6.8 parts.
[0030] In this invention, the mass fraction of desulfurized gypsum is preferably 6 to 14 parts, more preferably 8 to 12 parts, and even more preferably 9 to 10 parts.
[0031] In this invention, the mass fraction of silicate cement is preferably 5.5 to 7.5 parts, more preferably 6 to 7 parts, and even more preferably 6.5 to 6.8 parts.
[0032] In this invention, the mass fraction of quicklime is preferably 1.5 to 2.5 parts, more preferably 1.6 to 2.4 parts, and even more preferably 1.8 to 2 parts.
[0033] In this invention, the water-reducing agent is preferably 0.2 to 0.9 parts by mass, more preferably 0.3 to 0.8 parts, and even more preferably 0.4 to 0.5 parts by mass.
[0034] In this invention, the retarder is preferably 0.6 to 0.9 parts by mass, more preferably 0.65 to 0.85 parts by mass, and even more preferably 0.7 to 0.8 parts by mass.
[0035] In this invention, the mass fraction of the expanding agent is preferably 2.2 to 2.8 parts, more preferably 2.3 to 2.7 parts, and even more preferably 2.4 to 2.6 parts.
[0036] In this invention, the mass fraction of the fiber is preferably 1.2 to 1.8 parts, more preferably 1.3 to 1.7 parts, and even more preferably 1.4 to 1.6 parts.
[0037] In this invention, the water content is preferably 10.5 to 11.5 parts by mass, more preferably 10.6 to 11.4 parts by mass, and even more preferably 10.8 to 11.2 parts by mass.
[0038] In this invention, the quartz sand comprises quartz sand with a particle size of 0.6 to 1.5 mm and quartz sand with a particle size of 0.2 to 0.5 mm.
[0039] In this invention, the mass ratio of the quartz sand with a particle size of 0.6 to 1.5 mm to the quartz sand with a particle size of 0.2 to 0.5 mm is preferably 1:1 to 1.25, more preferably 1:1.05 to 1.2, and even more preferably 1:1.1 to 1.15.
[0040] In this invention, the particle size of the fluorite is preferably ≥200 mesh, more preferably ≥300 mesh, and even more preferably ≥400 mesh. The particle size of the desulfurized gypsum is preferably 200-300 mesh, more preferably 220-280 mesh, and even more preferably 240-260 mesh.
[0041] In this invention, the water-reducing agent is a naphthalene-based water-reducing agent and / or a polycarboxylate water-reducing agent.
[0042] In this invention, the retarder is sodium gluconate and / or citric acid.
[0043] In this invention, the expanding agent is UEA expanding agent.
[0044] In this invention, the fiber is polypropylene fiber or glass fiber.
[0045] In this invention, the length of the fiber is preferably 10-16 mm, more preferably 11-15 mm, and even more preferably 12-13 mm; the diameter is preferably 20-50 μm, more preferably 25-45 μm, and even more preferably 30-40 μm.
[0046] The present invention also provides a method for preparing the red mud-based non-fired precast component, comprising the following steps:
[0047] (1) Dry mix red mud, fly ash, fluorite, desulfurized gypsum, quartz sand, silicate cement and quicklime, and then add the remaining raw materials and mix to obtain a mixture;
[0048] (2) Press the mixture into a blank;
[0049] (3) Curing the blanks yields the red mud-based non-fired precast parts.
[0050] In this invention, the rotation speed of the dry mixing in step (1) is preferably 80-150 rpm, more preferably 90-140 rpm, and even more preferably 100-120 rpm; the time is preferably 20-30 min, more preferably 22-28 min, and even more preferably 24-26 min.
[0051] In this invention, the stirring speed in step (1) is preferably 200-400 rpm, more preferably 240-360 rpm, and even more preferably 280-320 rpm; the stirring time is preferably 10-20 min, more preferably 12-18 min, and even more preferably 14-16 min.
[0052] In this invention, the pressing pressure in step (2) is preferably 30-40 MPa, more preferably 32-38 MPa, and even more preferably 34-36 MPa; the holding time is preferably 1-2 min, more preferably 1.2-1.8 min, and even more preferably 1.4-1.6 min.
[0053] In this invention, the temperature for curing in step (3) is preferably 20-40°C, more preferably 25-35°C, and even more preferably 28-32°C; the humidity is preferably ≥80%, more preferably ≥85%, and even more preferably ≥90%; the time is preferably 7-15 days, more preferably 8-14 days, and even more preferably 10-12 days.
[0054] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0055] Example 1
[0056] Prepare the following raw materials in parts by weight: 32 parts red mud, 17 parts fly ash, 24 parts quartz sand, 6 parts fluorite, 14 parts desulfurized gypsum, 6 parts PO42.5 silicate cement, 2 parts quicklime, 0.5 parts water-reducing agent, 0.8 parts retarder, 2.5 parts UEA expansion agent, 1.4 parts fiber, and 11 parts water.
[0057] The composition of the quartz sand is as follows: the mass ratio of 0.6-1.5 mm quartz sand to 0.2-0.5 mm quartz sand is 1:1.1; the particle size of the fluorite is 300 mesh; the particle size of the desulfurized gypsum is 280 mesh; the water-reducing agent is a commercially available naphthalene-based water-reducing agent; the retarder is citric acid; and the fiber is polypropylene fiber with a length of 15 mm and a diameter of 30 μm.
[0058] Red mud, fly ash, fluorite, desulfurized gypsum, quartz sand, silicate cement, and quicklime were dry-mixed at 120 rpm for 25 minutes. Then, the remaining raw materials were added and the mixing speed was controlled at 300 rpm for another 20 minutes to obtain a mixture. The mixture was pressed at 35 MPa for 2 minutes to obtain a green body. The green body was cured at 30℃ and 85% humidity for 10 days to obtain red mud-based non-fired precast parts.
[0059] Example 2
[0060] Prepare the following raw materials in parts by weight: 31 parts red mud, 16 parts fly ash, 27 parts quartz sand, 5 parts fluorite, 6 parts desulfurized gypsum, 5 parts PO42.5 silicate cement, 1.7 parts quicklime, 0.8 parts water-reducing agent, 1 part retarder, 2.6 parts UEA expansion agent, 2 parts fiber, and 10 parts water.
[0061] The composition of the quartz sand is as follows: the mass ratio of 0.6-1.5 mm quartz sand to 0.2-0.5 mm quartz sand is 1:1; the particle size of the fluorite is 300 mesh; the particle size of the desulfurized gypsum is 200 mesh; the water-reducing agent is commercially available polycarboxylate water-reducing agent; the retarder is citric acid; and the fiber is glass fiber with a length of 10 mm and a diameter of 25 μm.
[0062] Red mud, fly ash, fluorite, desulfurized gypsum, quartz sand, silicate cement, and quicklime were dry-mixed at 150 rpm for 30 minutes. Then, the remaining raw materials were added and the mixing speed was controlled at 400 rpm for another 10 minutes to obtain a mixture. The mixture was pressed at 30 MPa for 1.5 minutes to obtain a green body. The green body was cured at 25°C and 80% humidity for 15 days to obtain red mud-based non-fired precast parts.
[0063] Example 3
[0064] Prepare the following raw materials in parts by weight: 34 parts red mud, 20 parts fly ash, 23 parts quartz sand, 7.5 parts fluorite, 13 parts desulfurized gypsum, 7 parts PO42.5 silicate cement, 2.6 parts quicklime, 0.5 parts water-reducing agent, 0.8 parts retarder, 3 parts UEA expansion agent, 1.4 parts fiber, and 12 parts water.
[0065] The composition of the quartz sand is as follows: the mass ratio of 0.6-1.5 mm quartz sand to 0.2-0.5 mm quartz sand is 1:1.2; the particle size of the fluorite is 400 mesh; the particle size of the desulfurized gypsum is 300 mesh; the water-reducing agent is commercially available polycarboxylate water-reducing agent; the retarder is sodium gluconate; and the fiber is glass fiber with a length of 10 mm and a diameter of 25 μm.
[0066] Red mud, fly ash, fluorite, desulfurized gypsum, quartz sand, silicate cement, and quicklime were dry-mixed at 90 rpm for 20 minutes. Then, the remaining raw materials were added and the mixing speed was controlled at 330 rpm for 15 minutes to obtain a mixture. The mixture was pressed at 38 MPa for 2 minutes to obtain a green body. The green body was cured at 40℃ and 90% humidity for 12 days to obtain red mud-based non-fired precast parts.
[0067] The performance of the red mud-based non-fired preforms prepared in Examples 1-3 was tested, and the results are recorded in Table 1.
[0068] Table 1 Performance Test Results
[0069]
[0070] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A red mud-based non-fired precast component, characterized in that, It is prepared from raw materials comprising the following parts by weight: Red mud 30-35 parts, fly ash 15-20 parts, quartz sand 20-30 parts, fluorite 5-8 parts, desulfurized gypsum 5-15 parts, silicate cement 5-8 parts, quicklime 1-3 parts, water-reducing agent 0.1-1 parts, retarder 0.5-1 parts, expansion agent 2-3 parts, fiber 1-2 parts, water 10-12 parts.
2. The red mud-based non-fired precast component as described in claim 1, characterized in that, The quartz sand comprises quartz sand with a particle size of 0.6 to 1.5 mm and quartz sand with a particle size of 0.2 to 0.5 mm; The mass ratio of the quartz sand with a particle size of 0.6 to 1.5 mm to the quartz sand with a particle size of 0.2 to 0.5 mm is 1:1 to 1.
25.
3. The red mud-based non-fired precast component as described in claim 2, characterized in that, The fluorite has a particle size ≥ 200 mesh, and the desulfurized gypsum has a particle size of 200-300 mesh.
4. The red mud-based non-fired precast component as described in claim 3, characterized in that, The water-reducing agent is a naphthalene-based water-reducing agent and / or a polycarboxylate water-reducing agent; The retarder is sodium gluconate and / or citric acid.
5. The red mud-based non-fired precast component as described in claim 4, characterized in that, The expanding agent is UEA expanding agent; The fiber is polypropylene fiber or glass fiber; The fiber has a length of 10–16 mm and a diameter of 20–50 μm.
6. The method for preparing the red mud-based non-fired precast component according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Dry mix red mud, fly ash, fluorite, desulfurized gypsum, quartz sand, silicate cement and quicklime, and then add the remaining raw materials and mix to obtain a mixture; (2) Press the mixture into a blank; (3) Curing the blanks yields the red mud-based non-fired precast parts.
7. The method for preparing red mud-based non-fired precast components as described in claim 6, characterized in that, The dry mixing speed in step (1) is 80-150 rpm, and the time is 20-30 min.
8. The method for preparing red mud-based non-fired precast components as described in claim 7, characterized in that, The stirring speed in step (1) is 200-400 rpm and the stirring time is 10-20 min.
9. The method for preparing red mud-based non-fired precast components as described in claim 8, characterized in that, The pressing pressure in step (2) is 30-40 MPa, and the holding time is 1-2 min.
10. The method for preparing red mud-based non-fired precast components as described in claim 9, characterized in that, The curing temperature in step (3) is 20-40℃, the humidity is ≥80%, and the time is 7-15 days.