Copper-molybdenum tailing-based alkali-activated cementitious material and preparation method thereof

Abstract

The application belongs to the field of solid waste resource utilization and building material technology, and particularly relates to a copper-molybdenum tailing-based alkali-activated cementing material and a preparation method thereof. The copper-molybdenum tailing-based alkali-activated cementing material comprises a solid waste dry mixture, an alkali-activator solution, a silicone-acrylate emulsion and modified nano-silicon dioxide; wherein the solid waste dry mixture is composed of the following components in parts by mass: copper-molybdenum tailing 50-70 parts; auxiliary calcareous material 10-30 parts; silicon-aluminum correction material 10-20 parts. The method can realize large-scale consumption of copper-molybdenum tailing and preparation of cementing material with excellent mechanical properties and good stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of solid waste resource utilization and building materials, and particularly relates to a copper-molybdenum tailings-based alkali-activated cementitious material and a preparation method thereof. BACKGROUND

[0002] Copper-molybdenum tailings are tailings produced after copper and molybdenum concentrates are extracted from copper-molybdenum ore through flotation. The main treatment method at present is stockpiling. Not only does it occupy land, but also it poses a risk of ecological environment pollution and geological disasters, seriously threatening the life and property safety of people in the mining area. How to resourcefully utilize copper-molybdenum tailings on a large scale and with high added value is a difficult problem to be solved in the mining and environmental protection fields.

[0003] Alkali-activated cementitious material is a new type of green building material, which uses solid waste rich in silicon and aluminum (such as slag, fly ash, etc.) as the main raw material, and forms a three-dimensional network structure with cementitious properties through the action of strong alkali activator. Compared with traditional Portland cement, it has the advantages of low energy consumption, low carbon dioxide emission, excellent mechanical properties, good corrosion resistance, etc. At present, the research on alkali-activated cementitious material mainly focuses on fly ash, blast furnace slag, etc. However, the content and activity of SiO2 and Al2O3 in copper-molybdenum tailings are significantly different from those in fly ash and slag, and it may contain specific impurities. Directly using existing formulations often leads to poor activation effect, resulting in low material strength and poor stability.

[0004] Chinese patent CN111454011B provides a method for preparing alkali-activated cementitious material from engineering slag and the alkali-activated cementitious material. The alkali-activated cementitious material is prepared from engineering slag without the need for mud and sand separation treatment or the addition of cement, and can fully recycle engineering slag.

[0005] Existing cementitious materials face the problems of insufficient strength and poor durability in actual application, especially in cold regions, their anti-freeze-thaw cycle performance is poor, which seriously restricts the service life of engineering structures.

[0006] Therefore, it is necessary to develop a special alkali-activated cementitious material formulation and preparation process for the mineralization characteristics of copper-molybdenum tailings. SUMMARY

[0007] The purpose of the present application is to provide a copper-molybdenum tailings-based alkali-activated cementitious material and a preparation method thereof.

[0008] In order to achieve the above purpose, the present application provides the following technical solutions:

[0009] A copper-molybdenum tailings-based alkali-activated cementitious material includes a solid waste dry mix, an alkali activator solution, a silicone-acrylic emulsion, and modified nano-silica; wherein the solid waste dry mix is ​​composed of the following components in parts by weight: 50-70 parts copper-molybdenum tailings; 10-30 parts auxiliary calcium materials; and 10-20 parts silica-alumina corrective materials.

[0010] The alkaline activator solution comprises sodium silicate solution, sodium hydroxide solution, and water. The modulus of sodium silicate in the alkaline activator solution (SiO2 / Na2O) is 1.2-2.0; the mass of Na2O in the alkaline activator solution, expressed as Na2O equivalent, is 4%-10% of the mass of the dry solid waste mixture; the mass ratio of water in the alkaline activator solution to the mass of the dry solid waste mixture is 0.40-0.60.

[0011] Preferably, the auxiliary calcium-containing material is one or more of granulated blast furnace slag powder, steel slag, and carbide slag. Its function is to provide the necessary Ca²⁺. + This promotes the formation of C-(A)-SH gel, which intertwines with NASH gel generated by tailings excitation, thus optimizing the microstructure.

[0012] Preferably, the silica-alumina corrective material is one or more of low-calcium fly ash and metakaolin. Its function is to adjust the Si / Al ratio and Al / Na ratio of the system, thereby improving the degree of reaction and the long-term stability of the material.

[0013] Preferably, the silicone-acrylic emulsion includes silicone-acrylic emulsion A and silicone-acrylic emulsion B in a mass ratio of (1.5-1.8):1.

[0014] Silicone-acrylic emulsion A has a viscosity of 500-1500 mPa·s, a glass transition temperature of 15-25℃, and freeze-thaw stability after 5 cycles. It is produced by Jiangsu Shengda New Material Technology Co., Ltd., and its model number is SD-528.

[0015] Silicone-acrylic emulsion B has a viscosity of 500-1500 mPa·s, a glass transition temperature of 13-28℃, a particle size of 50-80 nm, and freeze-thaw stability of 5 cycles. Jiangsu Shengda New Material Technology Co., Ltd., SD-5281 nano-silicone-acrylic emulsion.

[0016] The present invention utilizes a specific type of silicone-acrylic emulsion in the cementitious material, which can improve the strength of the cementitious material. Analysis shows that under these conditions, the silicone-acrylic emulsion can better synergize with modified nano-silica. The polymer film fills and seals capillaries and microcracks, making the pore structure of the material more refined, reducing macropores and increasing micropores. This denser microstructure greatly improves strength and durability, while significantly strengthening the interfacial transition zone, transforming it from the weakest link in the material into a reinforcing link.

[0017] Preferably, the silicone-acrylic emulsion accounts for 6-8% of the mass of the solid waste dry mixture.

[0018] Preferably, the method for preparing the modified nano-silica includes the following steps:

[0019] Step 1: Add polyetheramine to anhydrous xylene and disperse evenly to obtain a dispersion.

[0020] Step 2: Add triethylamine and γ-glycidoxypropyltrimethoxysilane to the dispersion, heat to react, and obtain a mixed system;

[0021] Step 3: Add nano-silica to anhydrous xylene and disperse evenly to obtain a nano-silica suspension;

[0022] Step 4: Add the nano-silica suspension to the mixing system and reflux the reaction under nitrogen protection; after the reaction is completed, filter and dry to obtain modified nano-silica.

[0023] Preferably, the active hydrogen equivalent of the amine in the polyetheramine is 130-135 g / eq.

[0024] Preferably, the molar ratio of amine groups to γ-glycidoxypropyltrimethoxysilane in the polyetheramine is (2-2.2):1.

[0025] In existing technologies, directly adding nano-silica to cementitious materials does not significantly improve performance. This invention modifies the nano-silica, improving the freeze-thaw resistance of the cementitious material. Analysis shows that the steric hindrance effect generated by the long polymer chains prevents the agglomeration of nano-SiO2 in the slurry, allowing it to disperse more uniformly and thus fill a wider range of pores more efficiently.

[0026] Preferably, the modified nano-silica accounts for 0.8-1.2% of the mass of the dry solid waste mixture.

[0027] The preparation method of the copper-molybdenum tailings-based alkali-activated cementitious material includes the following steps:

[0028] Step 1: Raw material pretreatment: The copper-molybdenum tailings are dried and ground to obtain pretreated copper-molybdenum tailings;

[0029] Step 2, Material Mixing: Mix the pretreated copper-molybdenum tailings, auxiliary calcareous materials, and silica-alumina corrective materials evenly to obtain a solid waste dry mix;

[0030] Step 3, Mixing and Molding: Mix the solid waste dry mixture, alkali activator solution, silicone acrylic emulsion and modified nano silica using a cement paste mixer for 4-6 minutes to obtain a uniform paste;

[0031] Step 5, Curing: After the slurry is formed, it is cured at room temperature of 20-25℃ to obtain copper-molybdenum tailings-based alkali-activated cementitious material.

[0032] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0033] 1. This invention is the first to use copper-molybdenum tailings as the main raw material (accounting for 50-70%) in alkali-activated gelling materials, achieving high-value utilization of bulk industrial solid waste and solving the environmental and safety problems caused by its stockpiling. Through the compounding of copper-molybdenum tailings, auxiliary calcareous materials, and silica-alumina corrective materials, a multi-element solid waste synergistic activation system is formed. The calcareous materials provide a strong framework, while the silica-alumina materials optimize the gel structure, jointly overcoming the deficiency of insufficient activity of copper-molybdenum tailings alone.

[0034] 2. The cementitious material prepared by this invention through optimized proportioning and curing system has excellent mechanical properties. Its 3-day compressive strength can reach more than 20MPa and its 28-day compressive strength can reach more than 40MPa, which meets the strength requirements of general building materials. The preparation process of this invention does not require high-temperature sintering, but only curing at a temperature of 20-25℃. Its energy consumption and carbon emissions are far lower than those of traditional cement, which is in line with the green and low-carbon development direction.

[0035] 3. This invention modifies nano-silica, thereby improving the freeze-thaw resistance of the cementitious material.

[0036] 4. This invention uses a specific type of silicone-acrylic emulsion. Under these conditions, the silicone-acrylic emulsion can better enhance the effect of modified nano-silica, thereby improving the strength of the cementitious material. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0038] All raw materials used in the following embodiments of the present invention are commercially available products:

[0039] JEFFAMINE® ED-600 polyetheramine, active hydrogen equivalent of amine (g / eq): 132, brand: Huntsman.

[0040] Nano-silica, Nanjing Tianxing New Materials Co., Ltd., model TSP-H10.

[0041] The copper-molybdenum tailings, by mass percentage, consist of the following: CaO 42.5%, SiO2 25.6%, Al2O3 5.3%, MgO 1.2%, and other components.

[0042] Granulated blast furnace slag powder, by mass percentage, has the following composition: SiO2 40.3%, CaO 38.5%, Al2O3 4.5%, Fe2O3 10.2%, MgO 4.7%, and other components.

[0043] Low-calcium fly ash, by mass percentage, has the following composition: SiO2 58.2%, CaO 4.1%, Al2O3 26.5%, Fe2O3 6.8%, MgO 1.3%, and other components.

[0044] The composition of carbide slag, by mass percentage, is as follows: SiO2 3.2%, Al2O3 1.4%, CaO 78.5%, Fe2O3 0.9%, and other components.

[0045] Metakaolin, by mass percentage, has the following composition: SiO2 53.4%, Al2O3 45.2%, Fe2O3 0.8%.

[0046] The steel slag, by mass percentage, has the following composition: SiO2 13.5%, CaO 38.6%, Al2O3 2.5%, Fe2O3 26.7%, MgO 4.3%, and other components.

[0047] Example 1

[0048] This embodiment provides a copper-molybdenum tailings-based alkali-activated cementitious material, comprising a solid waste dry mix, an alkali activator solution, a silicone-acrylic emulsion, and modified nano-silica. The solid waste dry mix consists of the following components by weight: 60 parts copper-molybdenum tailings; 25 parts auxiliary calcareous material (granulated blast furnace slag powder); and 15 parts silica-alumina corrective material (low-calcium fly ash). The silicone-acrylic emulsion accounts for 7% of the solid waste dry mix by weight. The modified nano-silica accounts for 1.0% of the solid waste dry mix by weight.

[0049] The alkaline activator solution includes sodium silicate solution, sodium hydroxide solution, and water. The modulus (SiO2 / Na2O) of sodium silicate in the alkaline activator solution is 1.4; the mass of Na2O in the alkaline activator solution, expressed as Na2O equivalent, is 6% of the mass of the dry solid waste mixture; the mass ratio of water in the alkaline activator solution to the mass of the dry solid waste mixture is 0.5.

[0050] Silicone-acrylic emulsions include silicone-acrylic emulsion A and silicone-acrylic emulsion B in a mass ratio of 1.6:1. Silicone-acrylic emulsion A has a viscosity of 500-1500 mPa·s, a glass transition temperature of 15-25℃, and freeze-thaw stability after 5 cycles. Jiangsu Shengda New Material Technology Co., Ltd. produces silicone-acrylic emulsion model SD-528. Silicone-acrylic emulsion B has a viscosity of 500-1500 mPa·s, a glass transition temperature of 13-28℃, a particle size of 50-80 nm, and freeze-thaw stability after 5 cycles. Jiangsu Shengda New Material Technology Co., Ltd. also produces nano-silicone-acrylic emulsion SD-5281.

[0051] The method for preparing the modified nano-silica includes the following steps:

[0052] Step 1: Take 44.16g of JEFFAMINE®ED-600 polyetheramine, add it to 1000mL of anhydrous xylene, and disperse it evenly to obtain a dispersion.

[0053] Step 2: Add 10 mL of triethylamine and γ-glycidoxypropyltrimethoxysilane to the dispersion. The molar ratio of amine to γ-glycidoxypropyltrimethoxysilane in JEFFAMINE® ED-600 polyetheramine is 2:1. React at 80 °C for 6 h to obtain a mixed system.

[0054] Step 3: Add 9.1g of anhydrous nano-silica to 500mL of anhydrous xylene and disperse evenly to obtain a nano-silica suspension;

[0055] Step 4: Add the nano-silica suspension to the mixing system and reflux at 120°C for 5 hours under nitrogen protection; after the reaction is completed, filter and dry to obtain modified nano-silica.

[0056] The preparation method of the copper-molybdenum tailings-based alkali-activated cementitious material includes the following steps:

[0057] Step 1: Raw material pretreatment: The copper-molybdenum tailings are dried at 105℃ to constant weight and then ground to a specific surface area of ​​450 m² / kg to obtain pretreated copper-molybdenum tailings.

[0058] Step 2, Material Mixing: Mix the pretreated copper-molybdenum tailings, auxiliary calcareous materials, and silica-alumina corrective materials evenly to obtain a solid waste dry mix;

[0059] Step 3, Mixing and Molding: Mix the solid waste dry mixture, alkali activator solution, silicone acrylic emulsion and modified nano silica using a cement paste mixer for 5 minutes to obtain a uniform paste;

[0060] Step 5, Curing: After the slurry is formed, it is cured at room temperature of 20℃ to obtain copper-molybdenum tailings-based alkali-activated cementitious material.

[0061] Example 2

[0062] This embodiment provides a copper-molybdenum tailings-based alkali-activated cementitious material, comprising a solid waste dry mix, an alkali activator solution, a silicone-acrylic emulsion, and modified nano-silica. The solid waste dry mix is ​​composed of the following components by weight: 65 parts copper-molybdenum tailings; 25 parts auxiliary calcareous materials (20 parts granulated blast furnace slag powder, 5 parts calcium carbide slag); and 10 parts silica-alumina corrective material (low-calcium fly ash). The silicone-acrylic emulsion accounts for 6% of the solid waste dry mix by weight. The modified nano-silica accounts for 1.2% of the solid waste dry mix by weight.

[0063] The alkaline activator solution includes sodium silicate solution, sodium hydroxide solution, and water. The modulus (SiO2 / Na2O) of sodium silicate in the alkaline activator solution is 1.2; the mass of Na2O in the alkaline activator solution, expressed as Na2O equivalent, is 4% of the mass of the dry solid waste mixture; the mass ratio of water in the alkaline activator solution to the mass of the dry solid waste mixture is 0.4.

[0064] Silicone-acrylic emulsions include silicone-acrylic emulsion A and silicone-acrylic emulsion B in a mass ratio of 1.5:1. Silicone-acrylic emulsion A has a viscosity of 500-1500 mPa·s, a glass transition temperature of 15-25℃, and freeze-thaw stability after 5 cycles. Jiangsu Shengda New Material Technology Co., Ltd. produces the SD-528 silicone-acrylic emulsion. Silicone-acrylic emulsion B has a viscosity of 500-1500 mPa·s, a glass transition temperature of 13-28℃, a particle size of 50-80 nm, and freeze-thaw stability after 5 cycles. Jiangsu Shengda New Material Technology Co., Ltd. also produces the SD-5281 nano-silicone-acrylic emulsion.

[0065] The method for preparing the modified nano-silica includes the following steps:

[0066] Step 1: Take 44.16g of JEFFAMINE®ED-600 polyetheramine, add it to 1000mL of anhydrous xylene, and disperse it evenly to obtain a dispersion.

[0067] Step 2: Add 10 mL of triethylamine and γ-glycidoxypropyltrimethoxysilane to the dispersion. The molar ratio of amine to γ-glycidoxypropyltrimethoxysilane in JEFFAMINE® ED-600 polyetheramine is 2:1. React at 80 °C for 6 h to obtain a mixed system.

[0068] Step 3: Add 9.1g of anhydrous nano-silica to 500mL of anhydrous xylene and disperse evenly to obtain a nano-silica suspension;

[0069] Step 4: Add the nano-silica suspension to the mixing system and reflux at 120°C for 5 hours under nitrogen protection; after the reaction is completed, filter and dry to obtain modified nano-silica.

[0070] The preparation method of the copper-molybdenum tailings-based alkali-activated cementitious material includes the following steps:

[0071] Step 1: Raw material pretreatment: The copper-molybdenum tailings are dried at 105℃ to constant weight and then ground to a specific surface area of ​​450 m² / kg to obtain pretreated copper-molybdenum tailings.

[0072] Step 2, Material Mixing: Mix the pretreated copper-molybdenum tailings, auxiliary calcareous materials, and silica-alumina corrective materials evenly to obtain a solid waste dry mix;

[0073] Step 3, Mixing and Molding: Mix the solid waste dry mixture, alkali activator solution, silicone acrylic emulsion and modified nano silica using a cement paste mixer for 5 minutes to obtain a uniform paste;

[0074] Step 5, Curing: After the slurry is formed, it is cured at room temperature of 20℃ to obtain copper-molybdenum tailings-based alkali-activated cementitious material.

[0075] Example 3

[0076] This embodiment provides a copper-molybdenum tailings-based alkali-activated cementitious material, comprising a solid waste dry mix, an alkali activator solution, a silicone-acrylic emulsion, and modified nano-silica. The solid waste dry mix consists of the following components by weight: 70 parts copper-molybdenum tailings; 20 parts auxiliary calcareous materials (15 parts granulated blast furnace slag powder, 5 parts steel slag); and 10 parts silica-alumina corrective materials (5 parts low-calcium fly ash, 5 parts metakaolin). The silicone-acrylic emulsion accounts for 8% of the solid waste dry mix by weight. The modified nano-silica accounts for 0.8% of the solid waste dry mix by weight.

[0077] The alkaline activator solution includes sodium silicate solution, sodium hydroxide solution, and water. The modulus (SiO2 / Na2O) of sodium silicate in the alkaline activator solution is 1.6; the mass of Na2O in the alkaline activator solution, expressed as Na2O equivalent, is 6% of the mass of the dry solid waste mixture; the mass ratio of water in the alkaline activator solution to the mass of the dry solid waste mixture is 0.45.

[0078] Silicone-acrylic emulsions include silicone-acrylic emulsion A and silicone-acrylic emulsion B in a mass ratio of 1.8:1. Silicone-acrylic emulsion A has a viscosity of 500-1500 mPa·s, a glass transition temperature of 15-25℃, and freeze-thaw stability after 5 cycles. Jiangsu Shengda New Material Technology Co., Ltd. produces silicone-acrylic emulsion model SD-528. Silicone-acrylic emulsion B has a viscosity of 500-1500 mPa·s, a glass transition temperature of 13-28℃, a particle size of 50-80 nm, and freeze-thaw stability after 5 cycles. Jiangsu Shengda New Material Technology Co., Ltd. also produces nano-silicone-acrylic emulsion SD-5281.

[0079] The method for preparing the modified nano-silica includes the following steps:

[0080] Step 1: Take 44.16g of JEFFAMINE®ED-600 polyetheramine, add it to 1000mL of anhydrous xylene, and disperse it evenly to obtain a dispersion.

[0081] Step 2: Add 10 mL of triethylamine and γ-glycidoxypropyltrimethoxysilane to the dispersion. The molar ratio of amine to γ-glycidoxypropyltrimethoxysilane in JEFFAMINE® ED-600 polyetheramine is 2:1. React at 80 °C for 6 h to obtain a mixed system.

[0082] Step 3: Add 9.1g of anhydrous nano-silica to 500mL of anhydrous xylene and disperse evenly to obtain a nano-silica suspension;

[0083] Step 4: Add the nano-silica suspension to the mixing system and reflux at 120°C for 5 hours under nitrogen protection; after the reaction is completed, filter and dry to obtain modified nano-silica.

[0084] The preparation method of the copper-molybdenum tailings-based alkali-activated cementitious material includes the following steps:

[0085] Step 1: Raw material pretreatment: The copper-molybdenum tailings are dried at 105℃ to constant weight and then ground to a specific surface area of ​​450 m² / kg to obtain pretreated copper-molybdenum tailings.

[0086] Step 2, Material Mixing: Mix the pretreated copper-molybdenum tailings, auxiliary calcareous materials, and silica-alumina corrective materials evenly to obtain a solid waste dry mix;

[0087] Step 3, Mixing and Molding: Mix the solid waste dry mixture, alkali activator solution, silicone acrylic emulsion and modified nano silica using a cement paste mixer for 5 minutes to obtain a uniform paste;

[0088] Step 5, Curing: After the slurry is formed, it is cured at room temperature of 20℃ to obtain copper-molybdenum tailings-based alkali-activated cementitious material.

[0089] Comparative Example 1

[0090] This comparative example is CN111454011B, a method for preparing alkali-activated cementitious materials using engineering waste soil, and the product of Example 2 of the alkali-activated cementitious materials.

[0091] Comparative Example 2

[0092] The difference between this comparative example and Example 1 is that the silicone-acrylic emulsion is silicone-acrylic emulsion A, with a viscosity of 500-1500 mPa·s, a glass transition temperature of 15-25℃, and freeze-thaw stability after 5 cycles. It is manufactured by Jiangsu Shengda New Material Technology Co., Ltd., and its model is SD-528 silicone-acrylic emulsion.

[0093] Comparative Example 3

[0094] The difference between this comparative example and Example 1 is that the silicone-acrylic emulsion is silicone-acrylic emulsion B, which has a viscosity of 500-1500 mPa·s, a glass transition temperature of 13-28℃, a particle size of 50-80 nm, and freeze-thaw stability of 5 cycles. Jiangsu Shengda New Material Technology Co., Ltd., SD-5281 nano silicone-acrylic emulsion.

[0095] Comparative Example 4

[0096] The difference between this comparative example and Example 1 is that the silicone-acrylic emulsion includes silicone-acrylic emulsion A and silicone-acrylic emulsion B in a mass ratio of 1:1.2. Silicone-acrylic emulsion A has a viscosity of 500-1500 mPa·s, a glass transition temperature of 15-25°C, and freeze-thaw stability after 5 cycles. It is produced by Jiangsu Shengda New Material Technology Co., Ltd., and its model is SD-528 silicone-acrylic emulsion. Silicone-acrylic emulsion B has a viscosity of 500-1500 mPa·s, a glass transition temperature of 13-28°C, a particle size of 50-80 nm, and freeze-thaw stability after 5 cycles. It is produced by Jiangsu Shengda New Material Technology Co., Ltd., and its model is SD-5281 nano silicone-acrylic emulsion.

[0097] Comparative Example 5

[0098] The difference between this comparative example and Example 1 is that the silicone-acrylic emulsion is model BADEFU RS-9966A, manufactured by Cansen Chemical New Materials (Shenzhen) Co., Ltd.

[0099] Comparative Example 6

[0100] The difference between this comparative example and Example 1 is that the modified nano-silica was replaced with nano-silica. Nanjing Tianxing New Materials Co., Ltd., model TSP-H10.

[0101] Comparative Example 7

[0102] The difference between this comparative example and Example 1 is that JEFFAMINE® ED-600 polyetheramine was replaced with JEFFAMINE® M-2070 polyetheramine. Brand: Huntsman. Amine active hydrogen equivalent (g / eq): 1040.

[0103] Performance testing

[0104] 1. Refer to GB / T17671 The 2021 "Test Method for Strength of Cement Mortar" tests the flexural and compressive strength of the cementitious materials in Examples 1-3 and Comparative Examples 1-7. The compression surfaces are selected as the two sides of the specimen during molding, with an area of ​​40mm × 40mm. The average value of the results from 6 specimens is taken.

[0105] 2. The test for the number of freeze-thaw cycles shall be conducted in accordance with GB / T50082. The freeze-thaw test as specified in 2024 shall be conducted with specimens measuring 100mm × 100mm × 400mm. At the end of the thawing and freezing operations, the center temperature of the specimen shall be controlled within 5°C and -18°C, respectively, and the transition time between thawing and freezing shall be 8 minutes.

[0106] The results are shown in Table 1.

[0107] Table 1 Performance test results of copper-molybdenum tailings-based alkali-activated cementitious materials

[0108]

[0109] As shown in Table 1, the gelling materials prepared in Examples 1-3 have high strength, good freeze-thaw resistance, and overall performance superior to existing products.

[0110] Comparative Examples 2-5 show that changing the type and ratio of silicone-acrylic emulsion reduces the strength of the gel material.

[0111] Comparative Examples 6-7 show that modifying nano-silica with a specific type of polyetheramine can significantly improve the freeze-thaw effect. Analysis reveals that the molecular weight and amine hydrogen equivalent of the polyetheramine used in Examples 1-3 are more optimized, resulting in a more reasonable number of reactive amine groups, better reaction with the silane coupling agent, and a higher grafting density, forming a dense polymer brush that achieves superior antifreeze and toughening functions.

[0112] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles 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 copper-molybdenum tailings-based alkali-activated cementitious material, characterized in that, It includes solid waste dry mix, alkaline activator solution, silicone-acrylic emulsion and modified nano-silica; wherein, the solid waste dry mix is ​​composed of the following components in parts by weight: 50-70 parts copper-molybdenum tailings; 10-30 parts auxiliary calcium material; 10-20 parts silicon-aluminum corrective material; The silicone-acrylic emulsion includes silicone-acrylic emulsion A and silicone-acrylic emulsion B with a mass ratio of (1.5-1.8):1; silicone-acrylic emulsion A has a viscosity of 500-1500 mPa·s and a glass transition temperature of 15-25℃; silicone-acrylic emulsion B is a nano silicone-acrylic emulsion with a viscosity of 500-1500 mPa·s, a glass transition temperature of 13-28℃, and a particle size of 50-80 nm. Methods for preparing modified nano-silica include: Step 1: Add polyetheramine to anhydrous xylene and disperse evenly to obtain a dispersion; Step 2: Add triethylamine and γ-glycidoxypropyltrimethoxysilane to the dispersion, heat to react, and obtain a mixed system; Step 3: Add nano-silica to anhydrous xylene and disperse evenly to obtain a nano-silica suspension; Step 4: Add the nano-silica suspension to the mixing system and reflux the reaction under nitrogen protection; after the reaction is complete, filter and dry to obtain modified nano-silica; Modified nano-silica accounts for 0.8-1.2% of the mass of dry solid waste mixture; Silicone-acrylic emulsion accounts for 6-8% of the mass of dry solid waste mixture.

2. The copper-molybdenum tailings-based alkali-activated cementitious material according to claim 1, characterized in that, The alkaline activator solution includes sodium silicate solution, sodium hydroxide solution and water. The modulus of sodium silicate in the alkaline activator solution is 1.2-2.

0. The mass ratio of water to solid waste dry mixture in the alkaline activator solution is 0.40-0.

60.

3. The copper-molybdenum tailings-based alkali-activated cementitious material according to claim 2, characterized in that, The auxiliary calcium material is one or more of granulated blast furnace slag powder, steel slag, and carbide slag.

4. The copper-molybdenum tailings-based alkali-activated cementitious material according to claim 1, characterized in that, The silica-aluminate correcting material is one or more of low-calcium fly ash and metakaolin.

5. The copper-molybdenum tailings-based alkali-activated cementitious material according to claim 1, characterized in that, The active hydrogen equivalent of amine in polyetheramine is 130-135 g / eq.

6. The copper-molybdenum tailings-based alkali-activated cementitious material according to claim 5, characterized in that, The molar ratio of amine groups to γ-glycidoxypropyltrimethoxysilane in polyetheramine is (2-2.2):

1.

7. A method for preparing a copper-molybdenum tailings-based alkali-activated cementitious material according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Raw material pretreatment: The copper-molybdenum tailings are dried and ground to obtain pretreated copper-molybdenum tailings; Step 2, Material Mixing: Mix the pretreated copper-molybdenum tailings, auxiliary calcareous materials, and silica-alumina corrective materials evenly to obtain a solid waste dry mix; Step 3, Mixing and Molding: Mix the solid waste dry mixture, alkali activator solution, silicone acrylic emulsion and modified nano silica using a cement paste mixer for 4-6 minutes to obtain a uniform paste; Step 5, Curing: After the slurry is formed, it is cured at room temperature of 20-25℃ to obtain copper-molybdenum tailings-based alkali-activated cementitious material.

Images