Preparation method for improving performance of high-sulfur tailing filling body by using industrial magnesium slag

Abstract

The invention relates to the field of filling mining, in particular to a preparation method for improving the performance of a high-sulfur tailing filling body by using industrial magnesium slag. In order to reduce the filling cost and realize low-cost green filling mining, high-sulfur tailings and gobi aggregates are used as mixed filling aggregates, and multi-element solid wastes such as magnesium slag, quicklime and desulfurized gypsum and a composite excitation solution are used for exciting the potential activity of superfine slag powder; and three-dimensional rodlike high-entropy alloy nanoparticles are introduced to prepare the filling body with excellent mechanical properties. Compared with the traditional Portland cement, the compressive strength and sulfate erosion resistance of the high-sulfur tailings filling body are improved, the resource utilization of the high-sulfur tailings in the filling field is promoted, and the economic cost and the safety risk of a mine are reduced.

Description

Technical Field

[0001] The invention relates to the field of filling mining, and in particular to a preparation method for improving the performance of a high-sulfur tailings filling body by utilizing industrial magnesium slag. Background Art

[0002] The main components of magnesium slag are similar to those of Portland cement clinker. When exposed to water, it can form hydration products with cementitious properties and exhibits a certain degree of hydration activity. Among these, the main component, β-C2S, has low early reactivity and a slow hydration rate. Therefore, magnesium slag is often used as a supplementary cementitious material, mixed with other waste residues or additives for modification or activation to achieve better cementitious properties. This process is also being applied in research on mining backfill processes. Combining the comprehensive utilization of solid waste magnesium slag with mine backfill not only addresses the environmental pollution issues associated with magnesium slag, but also effectively controls mine backfill costs and improves the strength and stability of the backfill.

[0003] High-sulfur tailings are solid waste generated during the mining process, and the higher sulfur element usually exists in the form of sulfate. The main characteristic of high-sulfur tailings is that it contains a high proportion of sulfide minerals, such as pyrite and other sulfides, which often exist in the tailings in a free state or with the ecosystem. During the surface storage process, the sulfides in the high-sulfur tailings will react with oxygen and water to produce acidic substances, releasing large amounts of sulfuric acid and heavy metal elements, causing serious pollution to the environment. Therefore, the storage of high-sulfur tailings not only occupies a large amount of land resources, but its potential acidic leachate also causes great harm to groundwater, soil and surrounding ecosystems. Considering using tailings as filling aggregate to backfill the mined-out area can not only relieve storage capacity pressure and reduce filling costs, but also reduce environmental pollution. Therefore, full tailings filling technology is a relatively mature method for tailings resource utilization. Studies have shown that the sulfides in high-sulfur tailings will affect the compressive strength of the filling body. The sulfides therein can react with calcium hydroxide in cement to form sulfate minerals, which will not only affect the strength of the filling body, but may also cause long-term expansion and cracking problems. Therefore, the alkaline substances (CaO / MgO) in the magnesium slag selected in the present invention react with sulfides to generate stable sulfates, reducing the risk of acid leaching. At present, mines mainly use mixed aggregates formed by high-sulfur tailings and Gobi aggregates, and the cementitious materials are composed of M 37.5 cement and slag powder; the filling slurry concentration is less than 80%, usually around 77%. However, the later strength of the cemented filling body mixed with high-sulfur tailings is affected by the erosion of sulfates. Therefore, exploring the mechanical properties of the high-sulfur tailings filling body in order to reduce the comprehensive cost of composite filling materials while meeting the long-term strength requirements of mine filling stability is an issue that needs to be urgently addressed by mines. To reduce backfill costs and achieve low-cost, green backfill mining, this invention uses high-sulfur tailings and Gobi aggregate as mixed backfill aggregates, magnesium slag, quicklime, slag powder, and desulfurized gypsum as cementing materials, and introduces three-dimensional rod-shaped high-entropy alloy nanoparticles to produce a backfill with excellent mechanical properties. Furthermore, the composite alkaline activator prepared in this invention improves the compressive strength and sulfate corrosion resistance of the magnesium slag-activated high-sulfur tailings-based backfill. Summary of the Invention

[0004] To overcome the shortcomings of the existing technology, the present invention provides a preparation method for improving the performance of high-sulfur tailings filling using industrial magnesium slag. This is achieved through the following technical solutions:

[0005] S1. Dry the industrial magnesium slag at 90-120°C to constant weight, crush it and place it in a ball mill for 6-8 hours; dry the high-sulfur tailings and Gobi aggregate for later use;

[0006] S2. Sodium hydroxide and cesium hydroxide are dissolved in deionized water in a certain proportion, and after ultrasonic treatment at 40 kHz for 5-10 minutes, the solution is heated to 43-47° C. while stirring to obtain a composite activator solution;

[0007] S3, dissolving phosphotungstic acid, rhenium chloride, ferric nitrate, copper sulfate, zirconium chloride, manganese sulfate, nickel nitrate, tungsten chloride and ascorbic acid in a certain proportion in a mixed solvent of ethanol, oleylamine, ethylene glycol and oleic acid, then transferring the mixture into a microwave reactor, setting the temperature to 143-155°C, the heating time to 5 minutes, the holding time to 80-110 minutes, and centrifuging after the reaction to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles;

[0008] S4, weighing 527.67-879.45g of high-sulfur tailings treated in step S1, 879.45-1231.23g of Gobi aggregate, 29.31-58.62g of industrial magnesium slag, 175.86-205.17g of slag powder, 11.73-23.45g of quicklime and 35.17-52.76g of desulfurized gypsum, 1.8-3.8g of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in step S3, 85mL The composite activator solution prepared in S2 and 548-656 mL of water are placed in a cement mortar mixer and stirred for 5-8 minutes to form a mixed filling slurry. The filling slurry is then injected into a standard mold and compacted using a vibrating table to remove air bubbles. The filling slurry that exceeds the mold is then scraped off with a metal ruler to smooth the surface of the cemented filling body sample. The mold is then numbered and placed in a standard constant temperature and humidity curing box for curing.

[0009] S5. Curing and performance control: Early curing: Curing for 7 days at 20±2℃ and humidity ≥95% to promote the slow hydration of MgO in magnesium slag and avoid expansion and cracking; Long-term stability treatment: Spray 5% Na2CO3 solution on the surface of the filling body to form an alkaline barrier to inhibit sulfur oxidation.

[0010] The specific operating steps of the present invention are as follows:

[0011] S1. Dry the industrial magnesium slag at 90-120°C to constant weight, crush it and put it into a ball mill for 6-8 hours; the high-sulfur tailings and Gobi aggregate need to be dried for later use. In this step, the fine particles smaller than 38μm in the high-sulfur tailings account for about 70%, which belongs to the fine-grained tailings. The mineral phase of the high-sulfur tailings is mainly composed of quartz, mica, gypsum and chlorite, with a burning vector of 17.03%; the Gobi aggregate is mainly inert components, and the proportion of less than 1mm reaches 39.12%; the purpose of drying is to avoid the influence of moisture content on the concentration of filling slurry.

[0012] S2. Preparation of composite activator: Dissolve 1.47-2.94g of sodium hydroxide and 0.48-0.96g of cesium hydroxide in 100mL of deionized water, treat with 40kHz ultrasound for 5-10min, and heat the solution to 43-47°C while stirring to obtain a composite activator solution. The alkalinity of CsOH added in this step is far superior to that of conventional alkali metal hydroxides. It can more efficiently destroy the Si-O and Al-O bonds in the raw materials, release active components, and shorten the induction period. Even in an environment of 5-15°C, CsOH can still maintain high reaction activity, avoiding the coagulation delay caused by low temperature of traditional activators. In addition, Cs + The ionic radius is significantly larger than that of Na + , forming a looser ion coordination structure in the gel network, reducing shrinkage stress and inhibiting microcrack growth. + It can be adsorbed on the surface of gel pores, reducing porosity and improving material density and impermeability. + The generated silicate network is more stable and its dissolution rate in acidic environment is higher than that of Na + Low base gelation extends material life. Cs-based geopolymers maintain structural stability at temperatures above 800°C. The use of CsOH in this step allows for both high alkalinity activation and silicate network construction, improving compressive strength.

[0013] S3. Preparation of three-dimensional rod-shaped high-entropy alloy nanoparticles: 1.4-1.9 g of phosphotungstic acid (PTA), 0.7-1.2 g of rhenium chloride, 1.1-2.3 g of ferric nitrate, 1.6-3.3 g of copper sulfate, 1.5-1.9 g of zirconium chloride, 3.2-4.1 g of manganese sulfate, 0.9-2.1 g of nickel nitrate, 0.6-0.9 g of tungsten chloride and 0.5-0.8 g of ascorbic acid were dissolved in 20 mL of ethanol and 15 mL of oleylamine. The mixture was then transferred to a 100 mL microwave reactor, set at 143-155°C, heated for 5 minutes, and held for 80-110 minutes. After the reaction, centrifugation was performed to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles. In this step, driven by Coulomb and van der Waals forces, these three-dimensional rod-shaped high-entropy alloy nanoparticles form and remain stable under the action of phosphotungstic acid clusters. The multi-element synergistic effect and unique nanostructure (three-dimensional rod-shaped morphology) between Re, Fe, Cu, Zr, Mn, W, and Ni significantly improves the compressive strength and ductility of the filler. The multiple metal elements form a solid solution, which strengthens the filler through atomic size differences and lattice distortion, further optimizing the microstructural stability of the filler. These three-dimensional rod-shaped high-entropy alloy nanoparticles exhibit excellent corrosion resistance and thermal stability, making them capable of resisting oxidative attack by active sulfides in high-sulfur tailings. The three-dimensional rod-shaped nanoparticles can be evenly dispersed in the filling matrix, and through mechanical interlocking and chemical bonding, the interfacial bonding between the magnesium slag and the filling is enhanced, the porosity is reduced, the density is improved, and the rheological properties of the filling slurry are optimized.

[0014] S4, weighing 527.67-879.45g of high-sulfur tailings treated in step S1, 879.45-1231.23g of Gobi aggregate, 29.31-58.62g of industrial magnesium slag, 175.86-205.17g of slag powder, 11.73-23.45g of quicklime and 35.17-52.76g of desulfurized gypsum, 1.8-3.8g of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in step S3, 78-96mL The composite activator solution prepared in S2 and 548-656 mL of water are placed together in a JJ-5 cement mortar mixer and stirred for 5-8 minutes to form a mixed filling slurry. The filling slurry is then injected into a standard mold and vibrated and compacted using a vibrating table to remove bubbles. The filling slurry that exceeds the mold is then scraped off with a metal ruler to smooth the surface of the cemented filling body sample. The mold is then numbered and placed in a YH-40B standard constant temperature and humidity curing box at a temperature of 20±1°C and a relative humidity of more than 90% for curing. In this step, the magnesium slag reacts with the sulfides in the tailings to form gypsum (CaSO4·2H2O), and CaO / MgO reacts with the sulfides to form stable sulfates, reducing the risk of acid leaching. The composite activator prepared using the present invention has both strong base excitation and silicate network formation capabilities. The three-dimensional rod-shaped high-entropy alloy nanoparticles provide a new solution for industrial magnesium slag-based high-sulfur tailings fillings through multi-dimensional synergistic effects such as mechanical enhancement, sulfur solidification, and microstructure optimization. In this step, the CaO contained in the magnesium slag reacts with the sulfides (such as FeS2) in the high-sulfur tailings to generate CaSO4·2H2O (gypsum) and CaCO3, which effectively solidify the sulfur element and inhibit sulfate corrosion and acid leaching. On the other hand, the slow hydration characteristics of MgO can compensate for the volume shrinkage caused by sulfide oxidation and reduce microcracks. In addition, the active SiO2 and Al2O3 in the magnesium slag participate in the geological polymerization reaction to form a three-dimensional network structure, so that the filling body meets the downhole filling requirements. Moreover, the MgO in the magnesium slag generates gel during long-term hydration, which improves the impermeability and sulfate corrosion resistance. In this step, high-sulfur tailings, Gobi aggregate, industrial magnesium slag, slag powder, quicklime and desulfurized gypsum are weighed as composite high-sulfur tailings filling raw materials;

[0015] S5. Curing and performance control: Early curing: Curing for 7 days at 20±2℃ and humidity ≥90% to promote the slow hydration of MgO in magnesium slag and avoid expansion and cracking; Long-term stability treatment: Curing for 28 days at 20±2℃ and humidity ≥90%. Due to the addition of three-dimensional rod-shaped high-entropy alloy nanoparticles and composite activator solution, the 28d bonded filling strength is significantly improved, and the strength value is much greater than the filling strength value using 100% cement.

[0016] When 100% cement is used for activation, and the ratio of high sulfur tailings to Gobi aggregate is set at 3:7, the strength value of high sulfur tailings filling body is R7 = 0.61 MPa, R28 =1.53MPa; when the ratio of high sulfur tailings to Gobi aggregate is 4:6, the strength value of high sulfur tailings filling body is R7=0.66MPa, R 28 =1.61MPa; when high sulfur tailings: Gobi aggregate = 5:5, the high sulfur tailings filling strength value R7 = 0.80MPa, R 28 =1.85MPa.

[0017] Preferably, the high-sulfur tailings of the present invention contain about 70% fine particles smaller than 38 μm, which is a fine-grained tailings.

[0018] Preferably: the mineral phase of the high-sulfur tailings of the present invention is mainly composed of quartz, mica, gypsum and chlorite, and the burning vector is 17.03%;

[0019] Preferably: the Gobi aggregate of the present invention is mainly composed of inert components, and the proportion of particles smaller than 1 mm reaches 39.12%;

[0020] Preferably, in S1 of the present invention, the industrial magnesium slag is dried at 90° C. to a constant weight, crushed and then placed in a ball mill for 6-8 hours; the high-sulfur tailings and Gobi aggregate need to be dried for later use.

[0021] Preferably, in S1 of the present invention, the industrial magnesium slag is dried at 120° C. to a constant weight, crushed and then placed in a ball mill for 6-8 hours; the high-sulfur tailings and Gobi aggregate need to be dried for later use.

[0022] Preferably: in S3 of the present invention, 1.4 g of phosphotungstic acid (PTA), 0.7 g of rhenium chloride, 1.1 g of ferric nitrate, 1.6 g of copper sulfate, 1.5 g of zirconium chloride, 3.2 g of manganese sulfate, 0.9 g of nickel nitrate, 0.6 g of tungsten chloride and 0.5 g of ascorbic acid are dissolved in a mixed solvent of 20 mL of ethanol, 15 mL of oleylamine, 8 mL of ethylene glycol and 5 mL of oleic acid, and then transferred to a 100 mL microwave reactor, the temperature is set to 143 ° C, the heating time is 5 min, the holding time is 80 min, and the reaction is centrifuged after completion to obtain three-dimensional rod-shaped high entropy alloy nanoparticles.

[0023] Preferably: in S3 of the present invention, 1.9 g of phosphotungstic acid (PTA), 1.2 g of rhenium chloride, 2.3 g of ferric nitrate, 3.3 g of copper sulfate, 1.9 g of zirconium chloride, 4.1 g of manganese sulfate, 2.1 g of nickel nitrate, 0.9 g of tungsten chloride and 0.8 g of ascorbic acid are dissolved in a mixed solvent of 20 mL of ethanol, 15 mL of oleylamine, 8 mL of ethylene glycol and 5 mL of oleic acid, and then transferred to a 100 mL microwave reactor, the temperature is set to 155 ° C, the heating time is 5 min, the holding time is 110 min, and the reaction is centrifuged after completion to obtain three-dimensional rod-shaped high entropy alloy nanoparticles.

[0024] Preferably: in S4 of the present invention, 879.45g of high-sulfur tailings, 1231.23g of Gobi aggregate, 58.62g of industrial magnesium slag, 205.17g of slag powder, 23.45g of quicklime and 52.76g of desulfurization gypsum, 3.8g of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared by S3, 85mL of composite activator solution prepared by S2 and 656mL of water are weighed and put into a model JJ-5 cement mortar mixer, and stirred for 5 minutes to form a mixed filling slurry; then the filling slurry is injected into a standard mold and vibrated and compacted using a vibration table to eliminate bubbles; then the filling slurry that exceeds the mold is scraped off with a metal ruler to smooth the surface of the cemented filling sample, and the mold is numbered and placed in a standard constant temperature and humidity curing box for curing.

[0025] Preferably: in S4 of the present invention, 527.67g of high-sulfur tailings, 879.45g of Gobi aggregate, 29.31g of industrial magnesium slag, 175.86g of slag powder, 11.73g of quicklime and 35.17g of desulfurized gypsum, 1.8g of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared by S3, 95mL of composite activator solution prepared by S2 and 548mL of water are weighed and put into a model JJ-5 cement mortar mixer, and stirred for 8 minutes to form a mixed filling slurry; then the filling slurry is injected into a standard mold and vibrated and compacted using a vibration table to eliminate bubbles; then the filling slurry that exceeds the mold is scraped off with a metal ruler to smooth the surface of the cemented filling sample, and the mold is numbered and placed in a standard constant temperature and humidity curing box for curing.

[0026] Preferably: the present invention adopts JA2003 electronic scale, which can be accurate to 0.001g ( Figure 1 ).

[0027] Preferably, the mold used in the present invention is a triple mold of 7.07 cm×7.07 cm×7.07 cm.

[0028] Preferably: the present invention adopts a standard mold

[0029] The present invention is beneficial in that:

[0030] 1. In the present invention, the sulfide content in the aggregate is reduced by adding Gobi aggregate. The alkaline substances (CaO / MgO) in the magnesium slag and slag powder react with the sulfide to form stable sulfate and silicate hydrate, thereby reducing the risk of acid leaching.

[0031] 2. The present invention utilizes the differences in chemical composition of multiple solid wastes and their pH neutralization properties to regulate the physical composition of the filling composite material, and develops a low-cost and high-performance multiple solid waste high-sulfur tailings filling material that can replace silicate cement, meeting the mine's requirements for the early and long-term mechanical strength of the cemented filling body.

[0032] 3. The comprehensive utilization rate of solid waste in the present invention is greater than 90%, which reduces heavy metal pollution in the tailings reservoir and the land occupied by magnesium slag storage, and has good environmental benefits.

[0033] 4. The present invention is simple to operate and has low production cost, which is conducive to mass production.

[0034] 5. The alkalinity of CsOH added in the present invention is far superior to that of conventional alkali metal hydroxides, which can more efficiently destroy the Si-O and Al-O bonds in the raw materials, release active components, shorten the induction period, and even in an environment of 5-15°C, CsOH can still maintain high reaction activity, avoiding the coagulation delay caused by low temperature of traditional activators. In addition, Cs + The ionic radius is significantly larger than that of Na + , forming a looser ion coordination structure in the gel network, reducing shrinkage stress and inhibiting microcrack growth. + It can be adsorbed on the surface of gel pores, reducing porosity and improving material density and impermeability. + The generated silicate network is more stable and its dissolution rate in acidic environment is higher than that of Na + Low alkalinity and extended material life. Cs-based geopolymers maintain structural stability at temperatures above 800°C. The use of CsOH in this invention allows for both high alkalinity activation and silicate network construction, improving compressive strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 , the JA2003 electronic balance used in the present invention.

[0036] Figure 2 , the raw materials used in the present invention.

[0037] Figure 3 , XRD pattern of the magnesium slag used in the embodiments of the present invention.

[0038] Figure 4 , scanning electron microscope image of the three-dimensional rod-shaped high entropy alloy nanoparticles prepared in Example 3 of the present invention.

[0039] Figure 5 , Transmission electron micrograph of the three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in Example 3 of the present invention.

[0040] Figure 6, Transmission electron micrograph of the three-dimensional rod-shaped high entropy alloy nanoparticles prepared in Comparative Example 6 of the present invention.

[0041] Figure 7 , pore size distribution curve of the N2 adsorption-desorption isotherm of the three-dimensional rod-shaped high entropy alloy nanoparticles prepared in Example 3 of the present invention.

[0042] Figure 8 , Transmission electron micrograph of the three-dimensional rod-shaped high entropy alloy nanoparticles prepared in Comparative Example 7 of the present invention. DETAILED DESCRIPTION

[0043] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0044] Example 1

[0045] S1. Dry the industrial magnesium slag at 90°C to constant weight, crush it and place it in a ball mill for 6 hours; the high-sulfur tailings and Gobi aggregate need to be dried for later use. In this step, the fine particles smaller than 38 μm in the high-sulfur tailings account for about 70%, which belongs to the fine-grained tailings. The mineral phase of the high-sulfur tailings is mainly composed of quartz, mica, gypsum and chlorite, with a burning vector of 17.03%; the Gobi aggregate is mainly inert components, and the proportion of less than 1 mm reaches 39.12%; the purpose of drying is to avoid the influence of moisture content on the concentration of filling slurry.

[0046] S2. Preparation of composite activator: Dissolve 1.47g of sodium hydroxide and 0.48g of cesium hydroxide in 100mL of deionized water, treat with 40kHz ultrasound for 5-10min, and heat the solution to 43°C while stirring to obtain a composite activator solution. The alkalinity of CsOH added in this step is much higher than that of conventional alkali metal hydroxides. It can more efficiently destroy the Si-O and Al-O bonds in the raw materials, release active components, and shorten the induction period. Even at 5°C, CsOH can still maintain high reaction activity, avoiding the coagulation delay caused by low temperature of traditional activators. In addition, Cs + The ionic radius is significantly larger than that of Na + , forming a looser ion coordination structure in the gel network, reducing shrinkage stress and inhibiting microcrack growth. + It can be adsorbed on the surface of gel pores, reducing porosity and improving material density and impermeability. +The generated silicate network is more stable and its dissolution rate in acidic environment is higher than that of Na + Low base gelation extends material life. Cs-based geopolymers maintain structural stability at temperatures above 800°C. The use of CsOH in this step allows for both high alkalinity activation and silicate network construction, improving compressive strength.

[0047] S3. Preparation of three-dimensional rod-shaped high-entropy alloy nanoparticles: 1.4 g of phosphotungstic acid (PTA), 0.7 g of rhenium chloride, 1.1 g of ferric nitrate, 1.6 g of copper sulfate, 1.5 g of zirconium chloride, 3.2 g of manganese sulfate, 0.9 g of nickel nitrate, 0.6 g of tungsten chloride and 0.5 g of ascorbic acid were dissolved in a mixed solvent of 20 mL of ethanol, 15 mL of oleylamine, 8 mL of ethylene glycol and 5 mL of oleic acid, and then transferred to a 100 mL microwave reactor, the temperature was set to 143 ° C, the heating time was 5 min, the holding time was 80 min, and after the reaction was completed, centrifugation was performed to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles; in this step, under the action of phosphotungstic acid clusters, these three-dimensional rod-shaped high-entropy alloy nanoparticles can be formed and maintained stably under the driving force of Coulomb force and van der Waals force. There is a multi-element synergistic effect and a unique nanostructure (three-dimensional rod-like morphology) between Re, Fe, Cu, Zr, Mn, W and Ni, which significantly improves the compressive strength and ductility of the filler. The multiple metal elements between Re, Fe, Cu, Zr, Mn, W and Ni form a solid solution, which produces solid solution strengthening through atomic size differences and lattice distortion, further optimizing the microstructural stability of the filler. The three-dimensional rod-shaped high-entropy alloy nanoparticles have excellent corrosion resistance and thermal stability, and can resist the oxidative erosion of active sulfides in high-sulfur tailings. The three-dimensional rod-shaped nanoparticles can be evenly dispersed in the filler matrix, and through mechanical interlocking and chemical bonding, the interfacial bonding between the magnesium slag and the filler is enhanced, the porosity is reduced, the density is improved, and the rheological properties of the filler slurry are optimized.

[0048] S4, weighed 527.67g high sulfur tailings treated in step S1, 879.45g Gobi aggregate, 29.31g industrial magnesium slag, 175.86g slag powder, 11.73g quicklime and 35.17g desulfurization gypsum, 1.8g three-dimensional rod-shaped high entropy alloy nanoparticles prepared in step S3, 78mL The composite activator solution prepared in S2 and 548 mL of water were placed together in a JJ-5 cement mortar mixer and stirred for 5 minutes to form a mixed filling slurry. The filling slurry was then injected into a standard mold and compacted using a vibrating table to remove bubbles. The filling slurry that exceeded the mold was then scraped off with a metal ruler to smooth the surface of the cemented filling body sample. The mold was numbered and placed in a YH-40B standard constant temperature and humidity curing box at a temperature of 20±1°C and a relative humidity of more than 90% for curing. In this step, the magnesium slag reacted with the sulfides in the tailings to form gypsum (CaSO4·2H2O), and CaO / MgO reacted with the sulfides to form stable sulfates, reducing the risk of acid leaching. The composite activator prepared using the present invention has both strong base excitation and silicate network formation capabilities. The three-dimensional rod-shaped high-entropy alloy nanoparticles provide a new solution for industrial magnesium slag-based high-sulfur tailings filling bodies through multi-dimensional synergistic effects such as mechanical enhancement, sulfur solidification, and microstructure optimization. In this step, the CaO contained in the magnesium slag reacts with the sulfides (such as FeS2) in the high-sulfur tailings to generate CaSO4·2H2O (gypsum) and CaCO3, which effectively solidify the sulfur element and inhibit sulfate corrosion and acid leaching. On the other hand, the slow hydration characteristics of MgO can compensate for the volume shrinkage caused by sulfide oxidation and reduce microcracks. In addition, the active SiO2 and Al2O3 in the magnesium slag participate in the geological polymerization reaction to form a three-dimensional network structure, so that the filling body meets the downhole filling requirements. Moreover, the MgO in the magnesium slag generates gel during long-term hydration, which improves the impermeability and sulfate corrosion resistance. In this step, high-sulfur tailings, Gobi aggregate, industrial magnesium slag, slag powder, quicklime and desulfurized gypsum are weighed as composite high-sulfur tailings filling raw materials;

[0049] S5. Curing and performance control: Early curing: Curing for 7 days at 20±2℃ and humidity ≥90% to promote the slow hydration of MgO in magnesium slag and avoid expansion and cracking; Long-term stability treatment: Curing for 28 days at 20±2℃ and humidity ≥90%. Due to the addition of three-dimensional rod-shaped high-entropy alloy nanoparticles and composite activator solution, the 28d bonded filling strength is significantly improved, and the strength value is much greater than the filling strength value using 100% cement.

[0050] Table 1 Chemical composition of magnesium slag and slag powder

[0051]

[0052] Figure 1 The JA2003 electronic balance used in the present invention. Figure 2 This is a picture of the raw materials used in the experiments of this invention. Table 1 shows the chemical composition of the magnesium slag and slag powder used in the examples of this invention. Analysis of Table 1 shows that the magnesium slag used is similar in chemical composition to the slag powder currently used in mines, with the main components including CaO, SiO2, MgO, Al2O3, and Fe2O3. The magnesium slag has higher calcium oxide and silicon dioxide content than the slag powder, but lower magnesium oxide and aluminum oxide content. The CaO content is >40%, indicating good gelling activity. Figure 3 The XRD pattern of the magnesium slag used in the examples of the present invention shows that the main minerals are γ-C2S and β-C2S, with a small amount of C3S and calcium forsterite (CaO·MgO·SiO2). Magnesium slag has a chemical composition similar to cementitious materials such as cement and slag, and contains mineral components with gelling properties such as β-C2S and C3S, indicating that magnesium slag has good application prospects.

[0053] Example 2

[0054] S1. Dry the industrial magnesium slag at 120°C to constant weight, crush it and place it in a ball mill for 8 hours; the high-sulfur tailings and Gobi aggregate need to be dried for later use. In this step, the fine particles smaller than 38 μm in the high-sulfur tailings account for about 70%, which belongs to fine-grained tailings. The mineral phase of the high-sulfur tailings is mainly composed of quartz, mica, gypsum and chlorite, with a burning vector of 17.03%; the Gobi aggregate is mainly inert components, and the proportion of less than 1 mm reaches 39.12%; the purpose of drying is to avoid the influence of moisture content on the concentration of filling slurry.

[0055] S2. Preparation of composite activator: Dissolve 2.94g of sodium hydroxide and 0.96g of cesium hydroxide in 100mL of deionized water, treat with 40kHz ultrasound for 10min, and heat the solution to 47°C while stirring to obtain a composite activator solution. The alkalinity of CsOH added in this step is much higher than that of conventional alkali metal hydroxides. It can more efficiently destroy the Si-O and Al-O bonds in the raw materials, release active components, and shorten the induction period. Even at 15°C, CsOH can still maintain high reaction activity, avoiding the coagulation delay caused by low temperature of traditional activators. In addition, Cs + The ionic radius is significantly larger than that of Na + , forming a looser ion coordination structure in the gel network, reducing shrinkage stress and inhibiting microcrack growth. + It can be adsorbed on the surface of gel pores, reducing porosity and improving material density and impermeability. + The generated silicate network is more stable and its dissolution rate in acidic environment is higher than that of Na +Low base gelation extends material life. Cs-based geopolymers maintain structural stability at temperatures above 800°C. The use of CsOH in this step allows for both high alkalinity activation and silicate network construction, improving compressive strength.

[0056] S3. Preparation of three-dimensional rod-shaped high-entropy alloy nanoparticles: 1.9 g of phosphotungstic acid (PTA), 1.2 g of rhenium chloride, 2.3 g of ferric nitrate, 3.3 g of copper sulfate, 1.9 g of zirconium chloride, 4.1 g of manganese sulfate, 2.1 g of nickel nitrate, 0.9 g of tungsten chloride and 0.8 g of ascorbic acid were dissolved in a mixed solvent of 20 mL of ethanol, 15 mL of oleylamine, 8 mL of ethylene glycol and 5 mL of oleic acid, and then transferred to a 100 mL microwave reactor, the temperature was set to 155 ° C, the heating time was 5 min, the holding time was 110 min, and after the reaction was completed, centrifugation was performed to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles; in this step, under the action of phosphotungstic acid clusters, these three-dimensional rod-shaped high-entropy alloy nanoparticles can be formed and maintained stably under the driving of Coulomb force and van der Waals force. There is a multi-element synergistic effect and a unique nanostructure (three-dimensional rod-like morphology) between Re, Fe, Cu, Zr, Mn, W and Ni, which significantly improves the compressive strength and ductility of the filler. The multiple metal elements between Re, Fe, Cu, Zr, Mn, W and Ni form a solid solution, which produces solid solution strengthening through atomic size differences and lattice distortion, further optimizing the microstructural stability of the filler. The three-dimensional rod-shaped high-entropy alloy nanoparticles have excellent corrosion resistance and thermal stability, and can resist the oxidative erosion of active sulfides in high-sulfur tailings. The three-dimensional rod-shaped nanoparticles can be evenly dispersed in the filler matrix, and through mechanical interlocking and chemical bonding, the interfacial bonding between the magnesium slag and the filler is enhanced, the porosity is reduced, the density is improved, and the rheological properties of the filler slurry are optimized.

[0057] S4, weighed 879.45g of high-sulfur tailings treated in step S1, 1231.23g of Gobi aggregate, 58.62g of industrial magnesium slag, 205.17g of slag powder, 23.45g of quicklime and 52.76g of desulfurized gypsum, 3.8g of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in step S3, 96mL The composite activator solution prepared in S2 and 656 mL of water were placed together in a JJ-5 cement mortar mixer and stirred for 8 minutes to form a mixed filling slurry. The filling slurry was then injected into a standard mold and compacted using a vibrating table to remove bubbles. The filling slurry that exceeded the mold was then scraped off with a metal ruler to smooth the surface of the cemented filling body sample. The mold was numbered and placed in a YH-40B standard constant temperature and humidity curing box at a temperature of 20±1°C and a relative humidity of more than 90% for curing. In this step, the magnesium slag reacted with the sulfides in the tailings to form gypsum (CaSO4·2H2O), and CaO / MgO reacted with the sulfides to form stable sulfates, reducing the risk of acid leaching. The composite activator prepared using the present invention has both strong base excitation and silicate network formation capabilities. The three-dimensional rod-shaped high-entropy alloy nanoparticles provide a new solution for industrial magnesium slag-based high-sulfur tailings filling bodies through multi-dimensional synergistic effects such as mechanical enhancement, sulfur solidification, and microstructure optimization. In this step, the CaO contained in the magnesium slag reacts with the sulfides (such as FeS2) in the high-sulfur tailings to generate CaSO4·2H2O (gypsum) and CaCO3, which effectively solidify the sulfur element and inhibit sulfate corrosion and acid leaching. On the other hand, the slow hydration characteristics of MgO can compensate for the volume shrinkage caused by sulfide oxidation and reduce microcracks. In addition, the active SiO2 and Al2O3 in the magnesium slag participate in the geological polymerization reaction to form a three-dimensional network structure, so that the filling body meets the downhole filling requirements. Moreover, the MgO in the magnesium slag generates gel during long-term hydration, which improves the impermeability and sulfate corrosion resistance. In this step, high-sulfur tailings, Gobi aggregate, industrial magnesium slag, slag powder, quicklime and desulfurized gypsum are weighed as composite high-sulfur tailings filling raw materials;

[0058] S5. Curing and performance control: Early curing: Curing for 7 days at 20±2℃ and humidity ≥90% to promote the slow hydration of MgO in magnesium slag and avoid expansion and cracking; Long-term stability treatment: Curing for 28 days at 20±2℃ and humidity ≥90%. Due to the addition of three-dimensional rod-shaped high-entropy alloy nanoparticles and composite activator solution, the 28d bonded filling strength is significantly improved, and the strength value is much greater than the filling strength value using 100% cement.

[0059] Comparative Example 1: Except that cesium hydroxide is not added in step S2, the remaining steps are the same as those in Example 2.

[0060] Comparative Example 2: Except that ascorbic acid is not added in step S3, the remaining steps are the same as those in Example 2.

[0061] Comparative Example 3: Except that oleic acid is not added in step S3, the remaining steps are the same as those in Example 2.

[0062] Comparative Example 4: Except that sodium hydroxide is not added in step S2, the remaining steps are the same as those in Example 2.

[0063] Comparative Example 5: Except that the composite activator solution is not added in step S4, the remaining steps are the same as those in Example 2.

[0064] During the experimental process of the present invention, step S2 prepares a composite activator solution to excite the high-sulfur tailings filling material. The reason is that the alkaline environment is not only conducive to inhibiting the precipitation of sulfate ions, but also helps to excite the active components in filling materials such as magnesium slag and slag powder. Therefore, the composition and type of alkaline excitation, as well as the dosage, are crucial to the test results. If the dosage of the composite activator solution is too small, the excitation effect cannot be achieved, and if the dosage is too much, the "alkalinity" phenomenon will occur. Secondly, before conducting the mechanical strength test of the high-sulfur tailings filling body, in order to reduce the error of the experimental operation process, the present invention grinds the top and bottom of the filling body sample with fine sandpaper, and uses a vernier caliper to measure the size of the sample, accurate to 0.02mm. The present invention performs a uniaxial compressive strength test on the filling body sample in accordance with the "Test Method for Cement Mortar Strength (ISO Method)" (GB / T 17671-1999). The present invention uses a standard mold The uniaxial compressive test (7d and 28d) was carried out using an electronic universal material testing machine of model INSTRON5969 (load range 100kN), and the constant displacement loading rate was set to 0.5mm / min. At the same time, the computer system collected the load and displacement data in real time. Table 2 shows the uniaxial compressive strength test results of the fillers prepared by Examples 1-2 of the present invention and Comparative Examples 1-4. In order to avoid the randomness of the experimental data, the test was conducted 5 times. According to the compressive strength values of 7d and 28d, the comparison of the results shows that the incorporation of the composite activator prepared by the present invention has a significant stimulating effect on the strength of the filler, and sodium hydroxide and cesium hydroxide have a synergistic effect in the composite activator solution and influence each other. In particular, the alkalinity of CsOH far exceeds that of conventional alkali metal hydroxides, and can more efficiently destroy the Si-O and Al-O bonds in the raw materials, release active components, shorten the induction period, and CsOH can still maintain high reactivity, avoiding the coagulation delay caused by low temperature of traditional activators. In addition, Cs + The ionic radius is significantly larger than that of Na + , forming a looser ion coordination structure in the gel network, reducing shrinkage stress and inhibiting microcrack growth. + It can be adsorbed on the surface of gel pores, reducing porosity and improving material density and impermeability. + The generated silicate network is more stable and its dissolution rate in acidic environment is higher than that of Na +The base gel is low, which extends the life of the material. The application of CsOH can take into account both high alkalinity excitation and silicate network construction, thereby improving the compressive strength. The uniaxial compressive strength test results of the fillers prepared in Examples 1-2 of the present invention and Comparative Examples 1-4 further prove that the composite alkaline activator prepared by the present invention improves the compressive strength and mechanical properties of the magnesium slag-activated high-sulfur tailings-based fillers. In addition, ascorbic acid and oleic acid are necessary chemicals for preparing the three-dimensional rod-shaped high-entropy alloy nanoparticles described in the present invention. No matter which one is missing, it is impossible to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles that meet the requirements, thereby affecting the uniaxial compressive strength test results of the final product.

[0065] Table 2 Uniaxial compressive strength test results

[0066] Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 7d(MPa) 3.53±0.03 2.65±0.04 3.01±0.05 2.95±0.01 2.85±0.03 2.03±0.01 28d(MPa) 5.68±0.01 3.42±0.03 3.89±0.02 3.76±0.03 3.49±0.02 3.11±0.02

[0067] Example 3

[0068] S1. Dry the industrial magnesium slag at 99°C to constant weight, crush it and place it in a ball mill for 7 hours; the high-sulfur tailings and Gobi aggregate need to be dried for later use. In this step, the fine particles smaller than 38μm in the high-sulfur tailings account for about 70%, which belongs to the fine-grained tailings. The mineral phase of the high-sulfur tailings is mainly composed of quartz, mica, gypsum and chlorite, with a burning vector of 17.03%; the Gobi aggregate is mainly inert components, and the proportion of less than 1mm reaches 39.12%; the purpose of drying is to avoid the influence of moisture content on the concentration of filling slurry.

[0069] S2. Preparation of composite activator: Dissolve 2.47g of sodium hydroxide and 0.56g of cesium hydroxide in 100mL of deionized water, treat with 40kHz ultrasound for 5-10min, and heat the solution to 45°C while stirring to obtain a composite activator solution. The alkalinity of CsOH added in this step is much higher than that of conventional alkali metal hydroxides. It can more efficiently destroy the Si-O and Al-O bonds in the raw materials, release active components, and shorten the induction period. Even at 9°C, CsOH can still maintain high reaction activity, avoiding the coagulation delay caused by low temperature of traditional activators. In addition, Cs + The ionic radius is significantly larger than that of Na + , forming a looser ion coordination structure in the gel network, reducing shrinkage stress and inhibiting microcrack growth. + It can be adsorbed on the surface of gel pores, reducing porosity and improving material density and impermeability. + The generated silicate network is more stable and its dissolution rate in acidic environment is higher than that of Na + Low base gelation extends material life. Cs-based geopolymers maintain structural stability at temperatures above 800°C. The use of CsOH in this step allows for both high alkalinity activation and silicate network construction, improving compressive strength.

[0070] S3. Preparation of three-dimensional rod-shaped high-entropy alloy nanoparticles: 1.5 g of phosphotungstic acid (PTA), 0.9 g of rhenium chloride, 1.9 g of ferric nitrate, 1.8 g of copper sulfate, 1.6 g of zirconium chloride, 3.5 g of manganese sulfate, 1.1 g of nickel nitrate, 0.7 g of tungsten chloride and 0.6 g of ascorbic acid were dissolved in a mixed solvent of 20 mL of ethanol, 15 mL of oleylamine, 8 mL of ethylene glycol and 5 mL of oleic acid, and then transferred to a 100 mL microwave reactor, the temperature was set to 149 ° C, the heating time was 5 min, the holding time was 99 min, and after the reaction was completed, centrifugation was performed to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles; in this step, under the action of phosphotungstic acid clusters, these three-dimensional rod-shaped high-entropy alloy nanoparticles can be formed and maintained stably under the driving force of Coulomb force and van der Waals force. There is a multi-element synergistic effect and a unique nanostructure (three-dimensional rod-like morphology) between Re, Fe, Cu, Zr, Mn, W and Ni, which significantly improves the compressive strength and ductility of the filler. The multiple metal elements between Re, Fe, Cu, Zr, Mn, W and Ni form a solid solution, which produces solid solution strengthening through atomic size differences and lattice distortion, further optimizing the microstructural stability of the filler. The three-dimensional rod-shaped high-entropy alloy nanoparticles have excellent corrosion resistance and thermal stability, and can resist the oxidative erosion of active sulfides in high-sulfur tailings. The three-dimensional rod-shaped nanoparticles can be evenly dispersed in the filler matrix, and through mechanical interlocking and chemical bonding, the interfacial bonding between the magnesium slag and the filler is enhanced, the porosity is reduced, the density is improved, and the rheological properties of the filler slurry are optimized.

[0071] S4, weighed 599.45g high sulfur tailings treated in step S1, 899.23g Gobi aggregate, 49.62g industrial magnesium slag, 195.17g slag powder, 13.45g quicklime and 45.17g desulfurization gypsum, 2.8g three-dimensional rod-shaped high entropy alloy nanoparticles prepared in step S3, 88mL The composite activator solution prepared in S2 and 556 mL of water were placed together in a JJ-5 cement mortar mixer and stirred for 7 minutes to form a mixed filling slurry. The filling slurry was then injected into a standard mold and compacted using a vibrating table to remove bubbles. The filling slurry that exceeded the mold was then scraped off with a metal ruler to smooth the surface of the cemented filling body sample. The mold was numbered and placed in a YH-40B standard constant temperature and humidity curing box at a temperature of 20±1°C and a relative humidity of more than 90% for curing. In this step, the magnesium slag reacted with the sulfides in the tailings to form gypsum (CaSO4·2H2O), and CaO / MgO reacted with the sulfides to form stable sulfates, reducing the risk of acid leaching. The composite activator prepared using the present invention has both strong base excitation and silicate network formation capabilities. The three-dimensional rod-shaped high-entropy alloy nanoparticles provide a new solution for industrial magnesium slag-based high-sulfur tailings filling bodies through multi-dimensional synergistic effects such as mechanical enhancement, sulfur solidification, and microstructural optimization. In this step, the CaO contained in the magnesium slag reacts with the sulfides (such as FeS2) in the high-sulfur tailings to generate CaSO4·2H2O (gypsum) and CaCO3, which effectively solidify the sulfur element and inhibit sulfate corrosion and acid leaching. On the other hand, the slow hydration characteristics of MgO can compensate for the volume shrinkage caused by sulfide oxidation and reduce microcracks. In addition, the active SiO2 and Al2O3 in the magnesium slag participate in the geological polymerization reaction to form a three-dimensional network structure, so that the filling body meets the downhole filling requirements. Moreover, the MgO in the magnesium slag generates gel during long-term hydration, which improves the impermeability and sulfate corrosion resistance. In this step, high-sulfur tailings, Gobi aggregate, industrial magnesium slag, slag powder, quicklime and desulfurized gypsum are weighed as composite high-sulfur tailings filling raw materials;

[0072] S5. Curing and performance control: Early curing: Curing for 7 days at 20±2℃ and humidity ≥90% to promote the slow hydration of MgO in magnesium slag and avoid expansion and cracking; Long-term stability treatment: Curing for 28 days at 20±2℃ and humidity ≥90%. Due to the addition of three-dimensional rod-shaped high-entropy alloy nanoparticles and composite activator solution, the 28d bonded filling strength is significantly improved, and the strength value is much greater than the filling strength value using 100% cement.

[0073] Comparative Example 6: Except that 1.6 g of phosphotungstic acid (PTA) is not added in step S2, the remaining steps are the same as those in Example 3.

[0074] Figure 4This is a scanning electron microscope image of the three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in Example 3 of the present invention. Figure 5 This is a transmission electron micrograph of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in Example 3 of the present invention. The image shows that the three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in the present invention are uniform in shape and size. When the material size is reduced to the nanometer scale, more atoms are exposed, significantly increasing the number of active sites. Figure 6 This is a transmission electron microscope image of the three-dimensional rod-shaped high entropy alloy nanoparticles prepared in comparative example 6 of the present invention. By comparing the high entropy alloy nanoparticles prepared in Example 3 and comparative example 6, it can be seen that phosphotungstic acid (PTA) clusters promote the formation of three-dimensional rod-shaped high entropy alloy nanoparticles. Under the action of phosphotungstic acid (PTA) clusters, these three-dimensional rod-shaped high entropy alloy nanoparticles can be formed and remain stable under the driving force of Coulomb force and van der Waals force. In the present invention, due to the oxygen-rich surface, phosphotungstic acid (PTA) can be used as a connector to achieve the aggregation of various metal oxides under covalent or non-covalent interactions. When phosphotungstic acid (PTA) clusters are not introduced into the multi-metal oxide system, only some small nanoparticles can be obtained and no three-dimensional nanorods can be obtained. Figure 7 The pore size distribution curve for the N2 adsorption-desorption isotherm of the three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in Example 3 of the present invention confirms the mesoporous structure of the three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in this invention. The exposed active sites and anisotropic structure of the three-dimensional nanorods increase the contact area between the high-entropy alloy nanoparticles and the filling slurry, allowing them to be evenly dispersed in the filling matrix. This mechanical interlocking and chemical bonding enhance the interfacial bonding between the magnesium slag and tailings, reducing porosity, improving compactness, and optimizing the rheological properties of the filling slurry.

[0075] Example 4

[0076] S1. Dry the industrial magnesium slag at 110°C to constant weight, crush it and place it in a ball mill for 7 hours; the high-sulfur tailings and Gobi aggregate need to be dried for later use. In this step, the fine particles smaller than 38 μm in the high-sulfur tailings account for about 70%, which belongs to the fine-grained tailings. The mineral phase of the high-sulfur tailings is mainly composed of quartz, mica, gypsum and chlorite, with a burning vector of 17.03%; the Gobi aggregate is mainly inert components, and the proportion of less than 1 mm reaches 39.12%; the purpose of drying is to avoid the influence of moisture content on the concentration of filling slurry.

[0077] S2. Preparation of composite activator: Dissolve 1.66g of sodium hydroxide and 0.86g of cesium hydroxide in 100mL of deionized water, treat with 40kHz ultrasound for 7min, and heat the solution to 45°C while stirring to obtain a composite activator solution. The alkalinity of CsOH added in this step is far superior to that of conventional alkali metal hydroxides. It can more efficiently destroy the Si-O and Al-O bonds in the raw materials, release active components, and shorten the induction period. Even at 11°C, CsOH can still maintain high reaction activity, avoiding the coagulation delay caused by low temperature of traditional activators. In addition, Cs + The ionic radius is significantly larger than that of Na + , forming a looser ion coordination structure in the gel network, reducing shrinkage stress and inhibiting microcrack growth. + It can be adsorbed on the surface of gel pores, reducing porosity and improving material density and impermeability. + The generated silicate network is more stable and its dissolution rate in acidic environment is higher than that of Na + Low base gelation extends material life. Cs-based geopolymers maintain structural stability at temperatures above 800°C. The use of CsOH in this step allows for both high alkalinity activation and silicate network construction, improving compressive strength.

[0078] S3. Preparation of three-dimensional rod-shaped high-entropy alloy nanoparticles: 1.6 g of phosphotungstic acid (PTA), 0.9 g of rhenium chloride, 1.6 g of ferric nitrate, 2.3 g of copper sulfate, 1.7 g of zirconium chloride, 3.8 g of manganese sulfate, 1.6 g of nickel nitrate, 0.8 g of tungsten chloride and 0.7 g of ascorbic acid were dissolved in a mixed solvent of 20 mL of ethanol, 15 mL of oleylamine, 8 mL of ethylene glycol and 5 mL of oleic acid, and then transferred to a 100 mL microwave reactor, the temperature was set to 149 ° C, the heating time was 5 min, the holding time was 95 min, and after the reaction was completed, centrifugation was performed to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles; in this step, under the action of phosphotungstic acid clusters, these three-dimensional rod-shaped high-entropy alloy nanoparticles can be formed and maintained stably under the driving force of Coulomb force and van der Waals force. There is a multi-element synergistic effect and a unique nanostructure (three-dimensional rod-like morphology) between Re, Fe, Cu, Zr, Mn, W and Ni, which significantly improves the compressive strength and ductility of the filler. The multiple metal elements between Re, Fe, Cu, Zr, Mn, W and Ni form a solid solution, which produces solid solution strengthening through atomic size differences and lattice distortion, further optimizing the microstructural stability of the filler. The three-dimensional rod-shaped high-entropy alloy nanoparticles have excellent corrosion resistance and thermal stability, and can resist the oxidative erosion of active sulfides in high-sulfur tailings. The three-dimensional rod-shaped nanoparticles can be evenly dispersed in the filler matrix, and through mechanical interlocking and chemical bonding, the interfacial bonding between the magnesium slag and the filler is enhanced, the porosity is reduced, the density is improved, and the rheological properties of the filler slurry are optimized.

[0079] S4, weighed 779.45g of high-sulfur tailings treated in step S1, 931.23g of Gobi aggregate, 38.62g of industrial magnesium slag, 185.17g of slag powder, 22.45g of quicklime and 50.76g of desulfurized gypsum, 2.8g of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in step S3, 88mL The composite activator solution prepared in S2 and 595 mL of water were placed together in a JJ-5 cement mortar mixer and stirred for 6 minutes to form a mixed filling slurry. The filling slurry was then injected into a standard mold and compacted using a vibrating table to remove bubbles. The filling slurry that exceeded the mold was then scraped off with a metal ruler to smooth the surface of the cemented filling body sample. The mold was numbered and placed in a YH-40B standard constant temperature and humidity curing box at a temperature of 20±1°C and a relative humidity of more than 90% for curing. In this step, the magnesium slag reacted with the sulfides in the tailings to form gypsum (CaSO4·2H2O), and CaO / MgO reacted with the sulfides to form stable sulfates, reducing the risk of acid leaching. The composite activator prepared using the present invention has both strong base excitation and silicate network formation capabilities. The three-dimensional rod-shaped high-entropy alloy nanoparticles provide a new solution for industrial magnesium slag-based high-sulfur tailings filling bodies through multi-dimensional synergistic effects such as mechanical enhancement, sulfur solidification, and microstructure optimization. In this step, the CaO contained in the magnesium slag reacts with the sulfides (such as FeS2) in the high-sulfur tailings to generate CaSO4·2H2O (gypsum) and CaCO3, which effectively solidify the sulfur element and inhibit sulfate corrosion and acid leaching. On the other hand, the slow hydration characteristics of MgO can compensate for the volume shrinkage caused by sulfide oxidation and reduce microcracks. In addition, the active SiO2 and Al2O3 in the magnesium slag participate in the geological polymerization reaction to form a three-dimensional network structure, so that the filling body meets the downhole filling requirements. Moreover, the MgO in the magnesium slag generates gel during long-term hydration, which improves the impermeability and sulfate corrosion resistance. In this step, high-sulfur tailings, Gobi aggregate, industrial magnesium slag, slag powder, quicklime and desulfurized gypsum are weighed as composite high-sulfur tailings filling raw materials;

[0080] S5. Curing and performance control: Early curing: Curing for 7 days at 20±2℃ and humidity ≥90% to promote the slow hydration of MgO in magnesium slag and avoid expansion and cracking; Long-term stability treatment: Curing for 28 days at 20±2℃ and humidity ≥90%. Due to the addition of three-dimensional rod-shaped high-entropy alloy nanoparticles and composite activator solution, the 28d bonded filling strength is significantly improved, and the strength value is much greater than the filling strength value using 100% cement.

[0081] Comparative Example 7: Except that 1.1 g of ammonium rhenate and 1.9 g of sodium tungstate are not added in step S3, the remaining steps are the same as those in Example 4.

[0082] Comparative Example 8: Except that 2.1 g of cobalt nitrate was not added in step S3, the remaining steps were the same as those in Example 4.

[0083] Comparative Example 9: Except that 3.8 g of copper sulfate is not added in step S3, the remaining steps are the same as those in Example 4.

[0084] Comparative Example 10: Except that three-dimensional rod-shaped high-entropy alloy nanoparticles are not added in step S4, the remaining steps are the same as those in Example 4.

[0085] Figure 8 This is a transmission electron microscope image of the three-dimensional rod-shaped high entropy alloy nanoparticles prepared in Comparative Example 7 of the present invention. Figure 8 and Figure 4 In comparison, it can be seen from the figure that without the participation of rhenium and tungsten metals, the three-dimensional rod-shaped nanoparticles are easy to agglomerate, which is not conducive to the application in filling slurries. The slump of the present invention is measured by selecting a slump barrel commonly used in concrete experiments. The filling slurry prepared in Example 4 of the present invention and Comparative Examples 7-10 is placed in the slump cylinder, vibrated according to the standard, and then the slump cylinder is lifted vertically and steadily. The difference between the final height of the collapse of the filling slurry under its own weight and the top of the slump cylinder is measured, and the slump is recorded; the expansion diameter of the filling slurry in the horizontal plane is measured and recorded as the expansion. The slump and expansion are manifestations of the flow properties of the filling slurry; under normal circumstances, the larger the slump and expansion indicators are, the better the flow properties of the filling slurry. According to Table 3, the addition of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared by the present invention can improve the flow properties of the high-sulfur tailings filling slurry, so that it meets the requirements of horizontal gravity and pipeline transportation. The speculated reason is that multiple metal elements such as Re, Fe, Cu, Zr, Mn, W and Ni form a solid solution, which produces solid solution strengthening through atomic size differences and lattice distortion, further optimizing the microstructural stability of the filling.

[0086] Table 3

[0087] Example 4 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Slump / cm 28.5 27.5 26.5 26.0 25.0 Expansion / cm 84.5×85.0 70.0×66.5 63.0×67.5 62.0×65.0 60.0×58.0

[0088] The above-described embodiments merely represent specific implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of the present invention. It should be noted that, for those skilled in the art, any changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention are equivalent replacements and are included within the scope of protection of the present invention.

Claims

1. A preparation method for improving the performance of high-sulfur tailings filling using industrial magnesium slag, characterized by: The specific operation steps are as follows: S1, drying the magnesium slag at 90-120 ° C to constant weight, crushing it and putting it into a ball mill for 6-8 hours; high-sulfur tailings and Gobi aggregates need to be dried for later use; S2, dissolving sodium hydroxide and cesium hydroxide in deionized water in a certain proportion, treating it with 40kHz ultrasound for 5-10 minutes, and heating the solution temperature to 43-47 ° C while stirring to obtain a composite activator solution; S3, dissolving phosphotungstic acid, rhenium chloride, ferric nitrate, copper sulfate, zirconium chloride, manganese sulfate, nickel nitrate, tungsten chloride and ascorbic acid in a mixed solvent of ethanol, oleylamine, ethylene glycol and oleic acid in a certain proportion, and then Transfer it to a microwave reactor, set the temperature to 143-155°C, the heating time to 5 minutes, the holding time to 80-110 minutes, and centrifuge after the reaction to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles; S4, weigh 527.67-879.45g of high-sulfur tailings, 879.45-1231.23g of Gobi aggregate, 29.31-58.62g of industrial magnesium slag, 175.86-205.17g of slag powder, 11.73-23.45g of quicklime and 35.17-52.76g of desulfurization gypsum, 1.8-3.8g of The three-dimensional rod-shaped high-entropy alloy nanoparticles prepared by S3, 85 mL of the composite activator solution prepared by S2, and 548-656 mL of water were put into a cement mortar mixer and stirred for 5-8 minutes to form a mixed filling slurry. The filling slurry was then injected into a standard mold and vibrated and compacted using a vibration table to remove bubbles. A metal ruler was then used to scrape off the filling slurry that exceeded the mold to smooth the surface of the cemented filling sample. The mold was numbered and placed in a standard constant temperature and humidity curing box for curing.

2. The method for improving the performance of high-sulfur tailings filling body by utilizing industrial magnesium slag according to claim 1, characterized in that: The specific steps are as follows: S1. Dry the industrial magnesium slag at 90-120°C to constant weight, crush it and place it in a ball mill for 6-8 hours; dry the high-sulfur tailings and Gobi aggregate for later use; S2. Dissolve 1.47-2.94 g of sodium hydroxide and 0.48-0.96 g of cesium hydroxide in 100 mL of deionized water, treat with 40 kHz ultrasound for 5-10 minutes, and heat the solution to 43-47° C. while stirring to obtain a composite activator solution; S3, dissolving 1.4-1.9 g of phosphotungstic acid, 0.7-1.2 g of rhenium chloride, 1.1-2.3 g of ferric nitrate, 1.6-3.3 g of copper sulfate, 1.5-1.9 g of zirconium chloride, 3.2-4.1 g of manganese sulfate, 0.9-2.1 g of nickel nitrate, 0.6-0.9 g of tungsten chloride and 0.5-0.8 g of ascorbic acid in a mixed solvent of 20 mL of ethanol, 15 mL of oleylamine, 8 mL of ethylene glycol and 5 mL of oleic acid, and then transferring it to a 100 mL microwave reactor, setting the temperature to 143-155 ° C, the heating time to 5 min, the holding time to 80-110 min, and centrifuging after the reaction to obtain three-dimensional rod-shaped high entropy alloy nanoparticles; S4, weighing 527.67-879.45g of high-sulfur tailings treated in step S1, 879.45-1231.23g of Gobi aggregate, 29.31-58.62g of industrial magnesium slag, 175.86-205.17g of slag powder, 11.73-23.45g of quicklime and 35.17-52.76g of desulfurized gypsum, 1.8-3.8g of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in step S3, 78-96mL The composite activator solution prepared in S2 and 548-656 mL of water are placed together in a JJ-5 cement mortar mixer and stirred for 5-8 minutes to form a mixed filling slurry. The filling slurry is then injected into a standard mold and vibrated and compacted using a vibrating table to remove bubbles. The filling slurry that exceeds the mold is then scraped off with a metal ruler to smooth the surface of the cemented filling sample. The mold is then numbered and placed in a standard constant temperature and humidity curing box for curing.

3. The method for improving the performance of high-sulfur tailings filling body by utilizing industrial magnesium slag according to claim 2, characterized in that: The fine-grained tailings account for 70% of the high-sulfur tailings.

4. The method for improving the performance of high-sulfur tailings filling by utilizing industrial magnesium slag according to claim 2 or 3, characterized in that: The mineral phase of the high-sulfur tailings is mainly composed of quartz, mica, gypsum and chlorite, and the burning content is 17.03%.

5. The method for improving the performance of high-sulfur tailings filling body by utilizing industrial magnesium slag according to claim 2, characterized in that: In S1, industrial magnesium slag is dried at 90° C. to a constant weight, crushed, and placed in a ball mill for 8 hours.

6. The method for improving the performance of high-sulfur tailings filling by utilizing industrial magnesium slag according to claim 2 or 5, characterized in that: In S1, industrial magnesium slag is dried at 120° C. to a constant weight, crushed, and placed in a ball mill for 6 hours.

7. The method for improving the performance of high-sulfur tailings filling body by utilizing industrial magnesium slag according to claim 2, characterized in that: In the S3, 1.4 g of phosphotungstic acid, 0.7 g of rhenium chloride, 1.1 g of ferric nitrate, 1.6 g of copper sulfate, 1.5 g of zirconium chloride, 3.2 g of manganese sulfate, 0.9 g of nickel nitrate, 0.6 g of tungsten chloride and 0.5 g of ascorbic acid are dissolved in a mixed solvent of 20 mL of ethanol, 15 mL of oleylamine, 8 mL of ethylene glycol and 5 mL of oleic acid, and then transferred to a 100 mL microwave reactor, the temperature is set to 143 ° C, the heating time is 5 min, the holding time is 80 min, and after the reaction is completed, centrifugation is performed to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles.

8. The method for improving the performance of high-sulfur tailings filling by utilizing industrial magnesium slag according to claim 2 or 7, characterized in that: In the S3, 1.9 g of phosphotungstic acid, 1.2 g of rhenium chloride, 2.3 g of ferric nitrate, 3.3 g of copper sulfate, 1.9 g of zirconium chloride, 4.1 g of manganese sulfate, 2.1 g of nickel nitrate, 0.9 g of tungsten chloride and 0.8 g of ascorbic acid were dissolved in a mixed solvent of 20 mL of ethanol, 15 mL of oleylamine, 8 mL of ethylene glycol and 5 mL of oleic acid, and then transferred to a 100 mL microwave reactor, the temperature was set to 155 ° C, the heating time was 5 min, the holding time was 110 min, and after the reaction was completed, centrifugation was performed to obtain three-dimensional rod-shaped high-entropy alloy nanoparticles.

9. The method for improving the performance of high-sulfur tailings filling material by utilizing industrial magnesium slag according to claim 2, characterized in that: In the step S4, 879.45 g of high-sulfur tailings treated in the step S1, 1231.23 g of Gobi aggregate, 58.62 g of industrial magnesium slag, 205.17 g of slag powder, 23.45 g of quicklime and 52.76 g of desulfurized gypsum, 3.8 g of three-dimensional rod-shaped high-entropy alloy nanoparticles prepared in S3, 85 mL of the composite activator solution prepared in S2 and 656 mL of water are weighed and put into a model JJ-5 cement mortar mixer, and stirred for 5 minutes to form a mixed filling slurry; then the filling slurry is injected into a standard mold and vibrated and compacted using a vibration table to eliminate bubbles; then the filling slurry exceeding the mold is scraped off with a metal ruler to smooth the surface of the cemented filling body sample, and the mold is numbered and placed in a standard constant temperature and humidity curing box for curing.

10. The three-dimensional rod-shaped high entropy alloy nanoparticles prepared according to any one of claims 7 or 8.

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