Tailing filling environment-friendly cementing material and preparation method thereof

Abstract

The invention relates to the technical field of building materials, and discloses a tailing filling environment-friendly cementing material and a preparation method thereof.The preparation method comprises the following specific steps that S1, materials are prepared, tailing is selected as a main raw material, and other materials including a cementing material, an exciting agent, an additive and water are selected; s2, pretreatment of tailings; s3, material mixing, specifically, the tailings, the cementing material, the exciting agent and the additive are weighed according to the proportion and put into a stirring machine for dry mixing; s4, adding water and stirring; s5, slurry pouring is conducted, specifically, accurate pouring is conducted through the 3D printing technology; and S6, the poured material is subjected to intermittent steam or microwave heating for curing. By effectively utilizing tailings and other industrial wastes (such as fly ash and superfine slag powder), the pollution of waste accumulation to the environment is reduced, reclaimed water or treated industrial wastewater is used, the consumption of fresh water resources is reduced, traditional cement is partially replaced, carbon emission in the production process is reduced, and the requirements of green building materials are met. Therefore, the environment-friendly effect can be achieved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to an environmentally friendly cementitious material for tailings backfilling and its preparation method. Background Technology

[0002] Tailings are fine-grained waste generated during mining operations and are usually piled up in tailings ponds. These tailings ponds not only occupy a large amount of land resources, but also pose potential environmental risks, such as infiltration pollution, soil heavy metal pollution, and water pollution. In addition, tailings piles up like mountains, which can easily trigger geological disasters such as landslides, posing a threat to the ecological environment and human life.

[0003] Currently, cement is the most widely used cementitious material in construction projects. However, the cement production process is energy-intensive and emits a lot of pollutants, which seriously affects the environment. With the promotion of the concept of sustainable development, how to reduce the amount of cement used and develop environmentally friendly cementitious materials using industrial waste has become a research hotspot in the field of building materials. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an environmentally friendly cementitious material for tailings backfilling and its preparation method, which solves the problems of high energy consumption and high emissions in the cement production process, which seriously affect the environment.

[0005] To achieve the above objectives, the present invention provides a method for preparing an environmentally friendly cementitious material for tailings backfilling, comprising the following specific steps:

[0006] S1: Material preparation, selecting tailings as the main raw material, and selecting other materials including cementitious materials, activators, admixtures, and water;

[0007] S2: Tailings pretreatment, which pretreatment of tailings to remove large impurities and excessively fine dust;

[0008] S3: Material mixing: Weigh out tailings, cementitious materials, activator and additives according to the proportion and put them into the mixer for dry mixing;

[0009] S4: Add water and stir. On the basis of dry mixing, gradually add an appropriate amount of water and continue stirring until a uniform slurry is formed.

[0010] S5: Grout casting. Precise casting is carried out using 3D printing technology. The well-mixed grout is poured into the mold or filling body for casting. Vibration is required during casting to remove air bubbles.

[0011] S6: The poured material is cured by intermittent steam or microwave heating.

[0012] Preferably, in step S1, the tailings are used in 50%-70% of the material, the cementing material includes modified cement, fly ash, and slag powder, the modified cement refers to cement with added nano-silicon or nano-titanium dioxide, the modified cement is used in 15%-20% of the material, the fly ash is used in 10%-15% of the material, the slag powder is used in 5%-10% of the material, the activator includes lime or water glass, the activator is used in 2%-5% of the material, the admixture includes plant cellulose and recycled plastic microspheres, the admixture is used in 0.5%-2% of the material, and the water is recycled water or treated industrial wastewater, with a water-to-material ratio of 0.4-0.5.

[0013] Preferably, in step S2, wet grading is used to classify the tailings according to particle size, controlling it between 0.1 and 0.5 mm, and magnetic separation or chemical treatment is used to remove heavy metals from the tailings.

[0014] Preferably, in step S3, the nano-additives, plasticizers, and fiber-reinforcing materials are added to the mixer simultaneously with the tailings, cementitious materials, activators, and additives for dry mixing.

[0015] Preferably, the nano-additives include carbon nanotubes and nano-titanium dioxide, and the nano-additives are used at 0.1%–0.5%; the plasticizer is selected from polycarboxylate superplasticizers, and the plasticizer is used at 0.2%–0.5%; the fiber reinforcement material includes basalt fiber and polypropylene fiber, and the fiber reinforcement material is used at 0.1%–0.3%.

[0016] Preferably, in step S3, the first premixing time is 4-6 minutes and the second mixing time is 2-4 minutes.

[0017] Preferably, in step S4, the mixture is stirred for 3 to 5 minutes using a mixer, and then stirred using ultrasonic-assisted stirring technology, with the stirring time controlled within 3 to 5 minutes.

[0018] Preferably, in step S6, the steam curing temperature is controlled at 50-70℃ for a curing time of 5-7 days.

[0019] Preferably, after step S6, a surface treatment is performed by spraying a curing agent onto the preliminarily hardened material surface to form a protective film to reduce moisture evaporation, and then covering it with a plastic film or a moisturizing cloth to further reduce moisture evaporation.

[0020] Preferably, the surface treatment is followed by final curing, which means continuing curing at room temperature for 28 days.

[0021] This invention provides an environmentally friendly cementitious material for tailings backfilling and its preparation method. It has the following beneficial effects:

[0022] 1. This invention reduces the pollution of the environment caused by waste accumulation by effectively utilizing tailings and other industrial wastes (such as fly ash and slag powder), and reduces the consumption of fresh water resources by using reclaimed water or treated industrial wastewater. It partially replaces traditional cement, reduces carbon emissions during the production process, and meets the requirements of green building materials, thereby achieving environmental protection effects.

[0023] 2. This invention reduces material costs by using inexpensive tailings and industrial waste to replace part of the cement, effectively utilizing industrial by-products, thereby improving resource utilization and reducing raw material waste.

[0024] 3. This invention improves the compressive strength of materials by using modified cement and nano-additives, making it suitable for engineering applications requiring high strength. The addition of fiber-reinforced materials improves the flexural strength of materials and reduces the risk of cracking and breakage. The use of nano-additives and composite activators enhances the toughness and crack resistance of materials and extends their service life, thereby enabling materials to possess excellent mechanical properties.

[0025] 4. The materials used in this invention have good acid and alkali resistance and corrosion resistance, making them suitable for various harsh environments. The materials are highly stable in low-temperature environments and are not prone to freeze-thaw damage, making them suitable for cold regions. The combination of high strength and high toughness allows the materials to maintain stable performance even in high-wear environments, thus giving the materials excellent durability.

[0026] 5. This invention uses plasticizers to give the slurry good fluidity, which facilitates construction operations. The use of 3D printing technology for precise casting reduces manual operations and improves construction efficiency and accuracy. The application of steam curing and microwave curing technologies shortens curing time and speeds up construction progress, thereby enabling the material to have excellent construction performance. Attached Figure Description

[0027] Figure 1 This is a flowchart of a method for preparing an environmentally friendly cementitious material for tailings backfilling according to the present invention. Detailed Implementation

[0028] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] Please see the appendix Figure 1This invention provides a method for preparing an environmentally friendly cementitious material for tailings backfilling, comprising the following specific steps:

[0031] S1: Material preparation, selecting tailings as the main raw material, and selecting other materials including cementitious materials, activators, admixtures, and water;

[0032] S2: Tailings pretreatment, which pretreatment of tailings to remove large impurities and excessively fine dust;

[0033] S3: Material mixing: Weigh out tailings, cementitious materials, activator and additives according to the proportion and put them into the mixer for dry mixing;

[0034] S4: Add water and stir. On the basis of dry mixing, gradually add an appropriate amount of water and continue stirring until a uniform slurry is formed.

[0035] S5: Grout casting. Precise casting is carried out using 3D printing technology. The well-mixed grout is poured into the mold or filling body for casting. Vibration is required during casting to remove air bubbles.

[0036] S6: The poured material is cured by intermittent steam or microwave heating.

[0037] In step S1, tailings account for 60% of the material. The cementing materials include modified cement, fly ash, and slag powder. Modified cement refers to cement with added nano-silicon or nano-titanium dioxide. Modified cement accounts for 18% of the material, fly ash accounts for 12%, and slag powder accounts for 7%. The activator includes lime, which accounts for 2.5%. The admixture includes plant cellulose, which accounts for 1.5%. The water used is reclaimed water or treated industrial wastewater, with a water-to-material ratio of 0.45.

[0038] In step S2, wet classification is used to classify the tailings according to particle size, controlling it between 0.1 and 0.5 mm, and magnetic separation or chemical treatment is used to remove heavy metals from the tailings.

[0039] In step S3, nano-additives, plasticizers, and fiber-reinforcing materials are added to the mixer along with tailings, cementitious materials, activators, and additives for dry mixing.

[0040] The nano-additives include nano-titanium dioxide, used at 0.3%; the plasticizer is selected from polycarboxylate superplasticizer, used at 0.3%; and the fiber reinforcement material includes basalt fiber, used at 0.2%.

[0041] In step S3, the first premixing time is 5 minutes, and the second mixing time is 3 minutes.

[0042] In step S4, use a mixer to stir for 3 to 5 minutes, and then use ultrasonic-assisted stirring technology to stir for 3 to 5 minutes.

[0043] In step S6, the steam curing temperature is controlled at 50-70℃ for 5-7 days.

[0044] After step S6, surface treatment is performed by spraying a curing agent onto the preliminarily hardened material surface to form a protective film to reduce moisture evaporation, and then covering it with a plastic film or moisturizing cloth to further reduce moisture evaporation.

[0045] After surface treatment, final curing is carried out, which means continuing curing at room temperature for 28 days.

[0046] Example 2:

[0047] Please see the appendix Figure 1 This invention provides a method for preparing an environmentally friendly cementitious material for tailings backfilling, comprising the following specific steps:

[0048] S1: Material preparation, selecting tailings as the main raw material, and selecting other materials including cementitious materials, activators, admixtures, and water;

[0049] S2: Tailings pretreatment, which pretreatment of tailings to remove large impurities and excessively fine dust;

[0050] S3: Material mixing: Weigh out tailings, cementitious materials, activator and additives according to the proportion and put them into the mixer for dry mixing;

[0051] S4: Add water and stir. On the basis of dry mixing, gradually add an appropriate amount of water and continue stirring until a uniform slurry is formed.

[0052] S5: Grout casting. Precise casting is carried out using 3D printing technology. The well-mixed grout is poured into the mold or filling body for casting. Vibration is required during casting to remove air bubbles.

[0053] S6: The poured material is cured by intermittent steam or microwave heating.

[0054] In step S1, tailings account for 55% of the material, and the cementing materials include modified cement, fly ash, and slag powder. Modified cement refers to cement with added nano-silicon or nano-titanium dioxide, accounting for 20% of the material. Fly ash accounts for 13%, slag powder accounts for 8%, activator includes water glass, accounting for 3%, and admixture includes recycled plastic microspheres, accounting for 1%. Reclaimed water or treated industrial wastewater is used, with a water-to-material ratio of 0.42.

[0055] In step S2, wet classification is used to classify the tailings according to particle size, controlling it between 0.1 and 0.5 mm, and magnetic separation or chemical treatment is used to remove heavy metals from the tailings.

[0056] In step S3, nano-additives, plasticizers, and fiber-reinforcing materials are added to the mixer along with tailings, cementitious materials, activators, and additives for dry mixing.

[0057] The nano-additives include carbon nanotubes, used at 0.3%; the plasticizer is selected from polycarboxylate superplasticizer, used at 0.3%; and the fiber reinforcement material includes polypropylene fibers, used at 0.2%.

[0058] In step S3, the first premixing time is 5 minutes, and the second mixing time is 3 minutes.

[0059] In step S4, use a mixer to stir for 3 to 5 minutes, and then use ultrasonic-assisted stirring technology to stir for 3 to 5 minutes.

[0060] In step S6, the steam curing temperature is controlled at 50-70℃ for 5-7 days.

[0061] After step S6, surface treatment is performed by spraying a curing agent onto the preliminarily hardened material surface to form a protective film to reduce moisture evaporation, and then covering it with a plastic film or moisturizing cloth to further reduce moisture evaporation.

[0062] After surface treatment, final curing is carried out, which means continuing curing at room temperature for 28 days.

[0063] Example 3:

[0064] Please see the appendix Figure 1 This invention provides a method for preparing an environmentally friendly cementitious material for tailings backfilling, comprising the following specific steps:

[0065] S1: Material preparation, selecting tailings as the main raw material, and selecting other materials including cementitious materials, activators, admixtures, and water;

[0066] S2: Tailings pretreatment, which pretreatment of tailings to remove large impurities and excessively fine dust;

[0067] S3: Material mixing: Weigh out tailings, cementitious materials, activator and additives according to the proportion and put them into the mixer for dry mixing;

[0068] S4: Add water and stir. On the basis of dry mixing, gradually add an appropriate amount of water and continue stirring until a uniform slurry is formed.

[0069] S5: Grout casting. Precise casting is carried out using 3D printing technology. The well-mixed grout is poured into the mold or filling body for casting. Vibration is required during casting to remove air bubbles.

[0070] S6: The poured material is cured by intermittent steam or microwave heating.

[0071] In step S1, tailings account for 50% of the material. The cementing materials include modified cement, fly ash, and slag powder. Modified cement refers to cement with added nano-silicon or nano-titanium dioxide. Modified cement accounts for 20% of the material, fly ash accounts for 15%, and slag powder accounts for 10%. The activator includes lime, which accounts for 3%. The admixtures include plant cellulose and recycled plastic microspheres, which account for 1%. The water used is reclaimed water or treated industrial wastewater, with a water-to-material ratio of 0.4.

[0072] In step S2, wet classification is used to classify the tailings according to particle size, controlling it between 0.1 and 0.5 mm, and magnetic separation or chemical treatment is used to remove heavy metals from the tailings.

[0073] In step S3, nano-additives, plasticizers, and fiber-reinforcing materials are added to the mixer along with tailings, cementitious materials, activators, and additives for dry mixing.

[0074] The nano-additives include carbon nanotubes and nano-titanium dioxide, with a usage of 0.4%. The plasticizer is selected from polycarboxylate superplasticizer, with a usage of 0.4%. The fiber reinforcement materials include basalt fiber and polypropylene fiber, with a usage of 0.2%.

[0075] In step S3, the first premixing time is 5 minutes, and the second mixing time is 3 minutes.

[0076] In step S4, use a mixer to stir for 3 to 5 minutes, and then use ultrasonic-assisted stirring technology to stir for 3 to 5 minutes.

[0077] In step S6, the steam curing temperature is controlled at 50-70℃ for 5-7 days.

[0078] After step S6, surface treatment is performed by spraying a curing agent onto the preliminarily hardened material surface to form a protective film to reduce moisture evaporation, and then covering it with a plastic film or moisturizing cloth to further reduce moisture evaporation.

[0079] After surface treatment, final curing is carried out, which means continuing curing at room temperature for 28 days.

[0080] Table 1: Properties of Environmentally Friendly Cementitious Materials for Tailings Backfilling in Different Embodiments

[0081]

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an environmentally friendly cementitious material for tailings backfilling, characterized in that, The specific steps include the following: S1: Material preparation, selecting tailings as the main raw material, and selecting other materials including cementitious materials, activators, admixtures, and water; S2: Tailings pretreatment, which pretreatment of tailings to remove large impurities and excessively fine dust; S3: Material mixing: Weigh out tailings, cementitious materials, activator and additives according to the proportion and put them into the mixer for dry mixing; S4: Add water and stir. On the basis of dry mixing, gradually add an appropriate amount of water and continue stirring until a uniform slurry is formed. S5: Grout casting. Precise casting is carried out using 3D printing technology. The well-mixed grout is poured into the mold or filling body for casting. Vibration is required during casting to remove air bubbles. S6: The poured material is cured by intermittent steam or microwave heating.

2. The method for preparing an environmentally friendly cementitious material for tailings backfilling according to claim 1, characterized in that, In step S1, tailings account for 50%-70% of the total content. The cementing material includes modified cement, fly ash, and slag powder. The modified cement refers to cement with added nano-silicon or nano-titanium dioxide. The modified cement accounts for 15%-20% of the total content. The fly ash accounts for 10%-15% of the total content. The slag powder accounts for 5%-10% of the total content. The activator includes lime or water glass. The activator accounts for 2%-5% of the total content. The admixture includes plant cellulose and recycled plastic microspheres. The admixture accounts for 0.5%-2% of the total content. The water used is reclaimed water or treated industrial wastewater, and the water-to-material ratio is 0.4-0.

5.

3. The method for preparing an environmentally friendly cementitious material for tailings backfilling according to claim 1, characterized in that, In step S2, wet classification is used to classify the tailings according to particle size, controlling it between 0.1 and 0.5 mm, and magnetic separation or chemical treatment is used to remove heavy metals from the tailings.

4. The method for preparing an environmentally friendly cementitious material for tailings backfilling according to claim 1, characterized in that, In step S3, nano-additives, plasticizers, and fiber-reinforcing materials are added to a mixer along with tailings, cementitious materials, activators, and additives for dry mixing.

5. The method for preparing an environmentally friendly cementitious material for tailings backfilling according to claim 4, characterized in that, The nano-additives include carbon nanotubes and nano-titanium dioxide, and the nano-additives are used at 0.1%–0.5%. The plasticizer is selected from polycarboxylate superplasticizers, and the plasticizer is used at 0.2%–0.5%. The fiber reinforcement material includes basalt fiber and polypropylene fiber, and the fiber reinforcement material is used at 0.1%–0.3%.

6. The method for preparing an environmentally friendly cementitious material for tailings backfilling according to claim 1, characterized in that, In step S3, the first premixing time is 4-6 minutes, and the second mixing time is 2-4 minutes.

7. The method for preparing an environmentally friendly cementitious material for tailings backfilling according to claim 1, characterized in that, In step S4, the mixture is stirred for 3 to 5 minutes using a mixer, and then stirred again using ultrasonic-assisted stirring technology, with the stirring time controlled within 3 to 5 minutes.

8. The method for preparing an environmentally friendly cementitious material for tailings backfilling according to claim 1, characterized in that, In step S6, the steam curing temperature is controlled at 50-70℃ for 5-7 days.

9. The method for preparing an environmentally friendly cementitious material for tailings backfilling according to claim 1, characterized in that, After step S6, surface treatment is performed by spraying a curing agent onto the preliminarily hardened material surface to form a protective film to reduce moisture evaporation, and then covering it with a plastic film or a moisturizing cloth to further reduce moisture evaporation.

10. The method for preparing an environmentally friendly cementitious material for tailings backfilling according to claim 9, characterized in that, After the surface treatment, final curing is performed, which means continuing curing at room temperature for 28 days.

Images