Efficient tailing consolidation agent in underground mine filling mining method and preparation method of efficient tailing consolidation agent

Abstract

The invention discloses an efficient consolidation agent for tailings in an underground mine filling mining method and a preparation method thereof, and relates to the technical field of consolidation agents, the consolidation agent is prepared from a gelling base material, a nano reinforcing agent, a chemical exciting agent and an organic fiber reinforcing agent according to a specific mass ratio; aiming at the problems of unstable volume, insufficient strength and the like of a traditional consolidation agent, through high-temperature calcination of the steel slag to eliminate harmful components, dealkalization treatment of the red mud, acid activation of the phosphogypsum and volcanic ash reaction of the fly ash, the volume stability and the gelling activity of a filling body are remarkably improved, and the consolidation agent is suitable for complex underground environment requirements; aiming at the pain points of low early strength, weak interface bonding and the like of the consolidation agent, the cohesion is improved by strong bonding of the surface-modified nano SiO2 and a gelling base material, a chemical exciting agent is added to cooperate with CO2 carbonization to generate nano crystal nucleuses, hydration sites are provided, a pore structure is optimized, bleeding is inhibited, the fluidity and stability of slurry can be effectively improved, and the consolidation effect is good. And the requirements of underground filling homogeneity and pumpability are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solidification agent, in particular to a tail sand efficient solidification agent in underground mine filling mining method and a preparation method thereof. BACKGROUND

[0002] Mine exploitation refers to the process of extracting economically valuable mineral resources (such as metals, coal, oil, natural gas, non-metallic minerals, etc.) from the earth's crust through scientific planning and technical means. Underground mine filling mining method is a core technology of green mining, which involves transporting tailings, waste rock, cementing materials and other filling materials to the goaf during the mining process to stabilize the structure of the goaf, control ground pressure, prevent rock mass and surface subsidence, ensure mine safety, improve mining efficiency, reduce loss rate, and achieve waste backfilling and resource recycling.

[0003] Tail sand solidification agent is a cementing material used in underground mine filling mining method to solidify tail sand into stable filling body. It is usually composed of cement, slag, steel slag, slag, gypsum, industrial solid waste, etc. It has synergistic effect and can form a solidified body with high strength and good stability under the condition of low ash sand ratio and high concentration slurry, realizing the resource utilization and heavy metal stabilization of tail sand. Tail sand solidification agent plays an important role in underground mine filling mining method, not only improving the safety and resource utilization rate of the mine, but also promoting the resource utilization of industrial solid waste, in line with the concept of green mine and sustainable development.

[0004] Existing tail sand solidification agents mostly rely on single industrial solid waste or simple compounding, which has the problems of complex composition, poor mineral phase stability, etc., resulting in large volume shrinkage and easy cracking. At the same time, the cementing system has insufficient activity, slow early strength development, weak interfacial bonding force, high slurry bleeding rate, and is difficult to meet the requirements of homogeneity, pumpability and long-term stability in underground filling. Therefore, the present application proposes a tail sand efficient solidification agent in underground mine filling mining method and a preparation method thereof to solve the problems existing in the prior art. SUMMARY

[0005] To solve the above problems, the present application proposes a tail sand efficient solidification agent in underground mine filling mining method and a preparation method thereof, which solves the problems of complex composition, poor mineral phase stability, etc. in existing tail sand solidification agents, resulting in large volume shrinkage and easy cracking, and the cementing system has insufficient activity, slow early strength development, weak interfacial bonding force.

[0006] In order to achieve the purpose of the present application, the present application realizes the following technical scheme: a tail sand efficient solidification agent in underground mine filling mining method, comprising the following raw materials by weight: 35-50 parts of cementing base material, 5-8 parts of nano reinforcing agent, 2-5 parts of chemical activator and 0.5-1.5 parts of organic fiber reinforcing agent;

[0007] The gelling base is prepared by mixing steel slag powder, calcined red mud, phosphogypsum and fly ash in a mass ratio of (3-3.5):(1.5-2):1:(4-6).

[0008] The nano-enhancing agent is nano-silica surface-modified by silane coupling agent KH-550, and the mass ratio of the silane coupling agent KH-550 to nano-silica is (3.5-4.5):10.

[0009] The chemical activator is prepared by compounding anhydrous sodium sulfate and industrial-grade triethanolamine in a mass ratio of (4-6):(1.5-2.5).

[0010] The organic fiber reinforcing agent is selected from one of polypropylene fiber or polyvinyl alcohol fiber, and the surface is etched by NaOH solution.

[0011] Further improvement lies in that the specific preparation method of the steel slag powder is as follows: first, the converter steel slag is crushed, calcined in a rotary kiln to eliminate free iron oxide, then quenched with water, and finally, 0.4-0.6% of borax crystal stabilizer based on the mass of the steel slag is jointly fed into a high-energy ball mill, and the steel slag powder is prepared after grinding.

[0012] Further improvement lies in that the specific preparation method of the calcined red mud is as follows: the Bayer process red mud is calcined in two stages, the first stage is to heat to 400-450℃ at a rate of 8-10℃ / min, and keep the temperature for 20-30min to remove crystal water, and the second stage is to heat to 650-750℃ at a rate of 3-5℃ / min, and keep the temperature for 1-2h to remove alkali, and the calcined red mud is prepared.

[0013] Further improvement lies in that the SO3 content of the phosphogypsum is ≥35%, and the particle size D90 is ≤45μm.

[0014] Further improvement lies in that the fly ash is low-calcium fly ash, and the total content of SiO2+Al2O3+Fe2O3 is ≥75%.

[0015] Further improvement lies in that the purity of the anhydrous sodium sulfate in the chemical activator is ≥99.5%, and the purity of the industrial-grade triethanolamine is ≥88%.

[0016] A preparation method of a tailing high-efficiency solidifying agent for underground mine filling mining method, comprising the following steps:

[0017] Step one: each raw material is weighed according to the preset weight ratio, the calcined red mud and the phosphogypsum are mixed first, then 10wt% citric acid solution accounting for 3-5% of the total mass of the calcined red mud and the phosphogypsum is added, and the mixture is stirred in a double-shaft stirrer to complex the alkali metal ions in the calcined red mud with the citric acid and convert part of the dihydrate gypsum in the phosphogypsum into hemihydrate gypsum, and the mixture is prepared.

[0018] Step two: the mixture is put into a closed vertical mill together with steel slag powder and fly ash, food-grade CO2 gas is introduced during the grinding process to make the residual free iron oxide in the steel slag react with CO2 to generate nano CaCO3 crystal nucleus, and the powder is prepared;

[0019] Step three: the nano-silicon dioxide and silane coupling agent KH-550 are added into an ethanol-water mixed solvent, and then ultrasonic dispersion treatment is carried out to form a uniform dispersion liquid, the dispersion liquid is evaporated and dried, and then ground to prepare a surface-modified nano-enhancing agent;

[0020] Step four: the powder obtained in step two, the nano-enhancing agent obtained in step three and the chemical activator are put into a high-efficiency three-dimensional mixer and mixed uniformly to obtain the tailings efficient solidifying agent.

[0021] Further improvement lies in that in step two, the flow rate of the introduced CO2 gas is 0.5-1 L / min, the CO2 concentration in the mill is maintained at 15-20%, and the grinding medium of the closed vertical mill is a steel ball with a diameter of 2-5 mm, and the filling rate is 35-40%.

[0022] The beneficial effects of the present application are: the present application eliminates harmful free iron oxide by using high-temperature calcined steel slag and restructures active mineral phases, removes crystal water and alkali metal by calcining red mud in a two-stage process, and reduces alkalinity, releases active ingredients by acid activation of phosphogypsum, and forms a synergistic system of active activation, alkalinity regulation and shrinkage inhibition by combining the pozzolanic reaction characteristics of low-calcium fly ash, effectively improving the volume stability of the material, reducing the risk of filling body cracking, and significantly improving the overall activity of the cementitious system, so that it can better adapt to the performance requirements of the solidifying material in the complex environment of underground mines;

[0023] And the nano-silicon dioxide modified by the silane coupling agent forms a strong interfacial bond with the cementitious base material through the bridging effect of the coupling agent, significantly improving the cohesion and crack resistance of the material, and the nano calcium carbonate crystal nucleus generated by the chemical activator combined with CO2 carbonization has a synergistic effect, which not only provides more hydration reaction sites to accelerate the development of early strength, but also optimizes the pore structure through the filling effect of the nano crystal nucleus, and inhibits the bleeding of the slurry; nano modification promotes micro combination, carbonation crystal nucleus strengthens hydration process, under the dual action, the prepared solidifying agent realizes the balance between rapid early strength improvement and continuous development of later strength, and the slurry flowability and stability are significantly improved, which can meet the strict requirements of underground filling on homogeneity, pumpability and long-term stability. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a preparation method flowchart of the tailings efficient solidifying agent in the underground mine filling mining method of the present application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0026] Underground mine filling mining method refers to transporting filling materials such as tailings, waste rock, cementing materials, etc. to the goaf for filling during the underground mining process. In this way, the structure of the goaf can be stabilized, ground pressure can be controlled, and rock mass and surface collapse can be prevented, thereby ensuring mine safety, improving mining efficiency, reducing loss rate, and realizing waste backfilling and resource recycling.

[0027] Underground mine filling mining method, as a safe, environmentally friendly and efficient mining method, is of great significance for ensuring mine safety, improving resource utilization rate and protecting the environment. Although some challenges are faced in the implementation process, these problems will be gradually solved with the continuous innovation and progress of technology, and the filling mining method will play a greater role in the future development of the mining industry.

[0028] It should be noted that the technical means not described in detail in the embodiments of the present application can be realized by conventional means, which is not the key point of the invention, and will not be described here.

[0029] Embodiment 1

[0030] The present embodiment provides a kind of tailings efficient consolidation agent in underground mine filling mining method, including following weight parts raw materials: cementitious base material 35 parts, nano reinforcing agent 5 parts, chemical activator 2 parts and organic fiber reinforcing agent 0.5 parts, by the selection of above-mentioned raw materials, multi-dimensional synergistic effect improves tailings consolidation performance, wherein:

[0031] The cementitious base material is a composite system of steel slag micro-powder, calcined red mud, phosphogypsum and fly ash, the mass ratio of steel slag micro-powder, calcined red mud, phosphogypsum and fly ash is 3:1.5:1:4, the SO3 content of phosphogypsum is ≥35%, the particle size D90 is ≤45 μm, and the attached water content is ≤1% after drying treatment, the fly ash is low-calcium fly ash, the total content of SiO2+Al2O3+Fe2O3 is ≥75%, the loss on ignition is ≤5%, and the specific surface area is ≥400 m 2 / kg, taking the composite system of steel slag micro-powder, calcined red mud, phosphogypsum and fly ash as the core, the performance complementation is realized by synergistic activation;

[0032] The nano reinforcing agent is nano silicon dioxide surface modified by silane coupling agent KH-550, wherein the particle size of nano silicon dioxide is 20 nm, the specific surface area is 150 m 2 / g, the mass ratio of the amount of silane coupling agent KH-550 to nano-silica is 3.5:10, the bridging effect of the coupling agent is used to improve the interface bonding between the nanoparticles and the gelling base material, the cohesion of the gelling system is enhanced through the nanoscale dispersed phase, the microcrack propagation is inhibited, and the early strength and crack resistance are improved;

[0033] The chemical activator is compounded by anhydrous sodium sulfate (purity ≥ 99%) and industrial-grade triethanolamine (purity ≥ 85%) according to a mass ratio of 4:1.5, the purity of anhydrous sodium sulfate is ≥ 99.5%, the purity of triethanolamine is ≥ 88%, anhydrous sodium sulfate is used as an active activator to destroy the inert structure of the gelling base material, accelerate the hydration reaction, and triethanolamine is used to adjust the setting time, delay the early hydration rate to avoid bleeding, and at the same time, catalyze the late strength development, and the combination of the two realizes the synergistic effect of "rapid activation-stable setting";

[0034] The organic fiber reinforcing agent is polypropylene fiber with a length of 3 mm, and the surface is etched by a mass fraction of 2% NaOH solution at 60°C for 30 min, by selecting the polypropylene fiber etched by NaOH, the surface roughness increases, and the mechanical engagement and interface adhesion between the gelling base material are significantly improved, a three-dimensional network structure can be formed in the slurry to enhance the anti-bleeding capacity and toughness, prevent the segregation and delamination of the filling body, and ensure the construction homogeneity.

[0035] In this embodiment, the preparation method of the steel slag micro-powder includes the following steps:

[0036] The converter steel slag is crushed to a particle size of ≤5 mm to increase the specific surface area of the material, shorten the subsequent calcination reaction time, improve the thermal energy utilization efficiency, and at the same time, provide a more uniform raw material basis for the grinding process, and the free iron oxide (f-CaO content ≤1.5%) is eliminated by calcining at 1250°C for 30 min in a rotary kiln, which can significantly improve the volume stability of the steel slag and avoid the cracking of the filling body due to hydration expansion in the solidifying agent;

[0037] Then, water quenching to below 200°C is used to inhibit the crystal growth of active minerals (such as C2S, C3S) in the steel slag, maintain its fine particle state and high reactivity, and at the same time, avoid the loss of activity caused by recrystallization of mineral phases, to provide more active sites for subsequent cementation reaction, and then, together with 0.4% borax crystal stabilizer of the mass of the steel slag, it is put into a high-energy ball mill, and ground to a specific surface area of ≥450 m 2 / kg, and CaO content ≥40%, MgO content ≤5%, finally, the high-activity, high-stability and composition-controllable steel slag micro-powder product is obtained, which provides the core cementing activity for the tailings solidifying agent.

[0038] In this embodiment, the calcined red mud is prepared by using Bayer process red mud and two-stage calcination:

[0039] The first stage is to increase the temperature to 400℃ at a rate of 8℃ / min and keep the temperature for 20min. The core target of this stage is to remove the crystal water in the red mud;

[0040] The second stage is to increase the temperature to 650℃ at a rate of 3℃ / min and keep the temperature for 1h. The core target of this stage is to remove the alkali metal oxides in the red mud, and finally the content of Fe2O3 is ≥25%, the content of Na2O is ≤2.5%, the specific surface area is ≥300m 2 / kg.

[0041] After two-stage calcination, the specific surface area of the red mud is increased, which significantly increases the contact area with the cementitious matrix such as steel slag micro-powder, phosphogypsum, etc.

[0042] Referring to Figure 1 , the embodiment also provides a preparation method of tailings efficient solidification agent in underground mine filling mining method, comprising the following steps:

[0043] Step one, pretreatment activation

[0044] According to the weight ratio of each raw material, each raw material is weighed in advance for standby. The calcined red mud and the phosphogypsum are mixed in a mass ratio of 1.5:1, 10wt% citric acid solution accounting for 3% of the total mass of the two is added, and stirring is carried out in a double-shaft stirrer (rotating speed 60rpm) for 30min. The alkali metal ions (Na + , K + ) in the red mud are complexed with citric acid, and part of the dihydrate gypsum in the phosphogypsum is converted into hemihydrate gypsum.

[0045] Step two, composite grinding and carbonization

[0046] The mixture obtained in step one, steel slag micro-powder and fly ash are jointly put into a closed vertical mill (feed particle size ≤10mm), the grinding medium is a steel ball with a diameter of 2mm, the filling rate is 35%, food-grade CO2 gas (purity ≥99.9%) is introduced into the mill at a flow rate of 0.5L / min during the grinding process, the CO2 concentration in the closed vertical mill is maintained at 15% (volume fraction), the grinding time is controlled at 20min, and the discharge temperature is ≤80℃. The residual f-CaO in the steel slag reacts with CO2 to generate nano CaCO3 crystal nucleus (particle size ≤100nm), the carbonation conversion rate of the residual f-CaO in the steel slag is ≥85%, and the dispersity of the generated nano CaCO3 crystal nucleus in the powder is ≥90%.

[0047] Step three, preparation of nano modifier

[0048] Nano silicon dioxide with a particle size of 20nm and silane coupling agent KH-550 are weighed in a mass ratio of 4:1, ethanol-water mixed solvent (ethanol:water volume ratio=3:1) is added, and ultrasonic dispersion (frequency 40kHz, power 500W) is carried out for 15min to form a uniform dispersion liquid.

[0049] The dispersion was dried by rotary evaporation at 60°C, and then ground until no hard agglomerates were formed to obtain a surface-modified nano-reinforcing agent.

[0050] Step 4: Homogenization and Combination

[0051] The powder obtained in step two (specific surface area ≥ 400 m² / kg), the nano-reinforcing agent obtained in step three, and the chemical activator are put into a high-efficiency three-dimensional mixer (speed 60 rpm) and mixed for 10 minutes until uniform, thus obtaining the solidifying agent product.

[0052] Example 2

[0053] This embodiment provides a high-efficiency tailings consolidation agent for underground mine backfilling mining, comprising the following raw materials in parts by weight: 50 parts of cementitious substrate, 8 parts of nano-reinforcing agent, 5 parts of chemical activator, and 1.5 parts of organic fiber reinforcing agent. Through the selection of the above raw materials, the tailings consolidation performance is improved through multi-dimensional synergistic effects, wherein:

[0054] The cementitious substrate is a composite system of steel slag powder, calcined red mud, phosphogypsum, and fly ash. The mass ratio of steel slag powder, calcined red mud, phosphogypsum, and fly ash is 3.5:2:1:6. The phosphogypsum has an SO3 content ≥35%, a particle size D90 ≤45μm, and an adhering water content ≤1% after drying. The fly ash is low-calcium fly ash with a total SiO2+Al2O3+Fe2O3 content ≥75%, a loss on ignition ≤5%, and a specific surface area ≥400m². 2 / kg, with a composite system of steel slag powder, calcined red mud, phosphogypsum and fly ash as the core, and complementary performance is achieved through synergistic activation;

[0055] The nano-reinforcing agent is nano-silica modified with silane coupling agent KH-550, wherein the nano-silica has a particle size of 50 nm and a specific surface area of ​​200 m². 2 / g, the mass ratio of silane coupling agent KH-550 to nano silica is 4.5:10. The coupling agent improves the interfacial bonding between nanoparticles and cementitious substrate by bridging the gap. The dispersion phase at the nanoscale enhances the cohesive force of the cementitious system, inhibits the propagation of microcracks, and improves early strength and crack resistance.

[0056] The chemical activator is a compound of anhydrous sodium sulfate (purity ≥99%) and industrial-grade triethanolamine (purity ≥85%) in a mass ratio of 6:2.5. The purity of anhydrous sodium sulfate is ≥99.5%, and the purity of triethanolamine is ≥88%. Anhydrous sodium sulfate acts as an active activator, which destroys the inert structure of the gelling substrate and accelerates the hydration reaction. Triethanolamine regulates the setting time, delays the early hydration rate to avoid bleeding, and catalyzes the development of strength in the later stage. The compound of the two achieves a synergistic effect of "rapid activation-stable setting".

[0057] The organic fiber reinforcing agent is polyvinyl alcohol fiber with a length of 6 mm, and the surface is etched by a 3% NaOH solution at 60°C for 30 min. By selecting polyvinyl alcohol fiber etched by NaOH, the surface roughness increases, the mechanical engagement and interfacial adhesion with the gelling base material are significantly improved, a three-dimensional network structure can be formed in the slurry, the anti-bleeding ability and toughness are enhanced, the separation and delamination of the filling body are prevented, and the uniformity of construction is ensured.

[0058] In this embodiment, the preparation method of the steel slag powder includes the following steps:

[0059] The converter steel slag is crushed to a particle size of ≤5 mm to increase the specific surface area of the material, shorten the subsequent calcination reaction time, improve the thermal energy utilization efficiency, and provide a more uniform raw material basis for the grinding process. Calcination at 1350°C for 40 min in a rotary kiln can eliminate free iron oxide (f-CaO content ≤1.5%), which can significantly improve the volume stability of the steel slag and prevent cracking of the filling body due to hydration expansion in the solidification agent;

[0060] Subsequently, water quenching to below 200°C, using rapid cooling to inhibit the crystal growth of active minerals (such as C2S, C3S) in the steel slag, maintaining its fine particle state and high reactivity, while avoiding the loss of activity caused by recrystallization of mineral phases, providing more active sites for subsequent cementation reactions, then adding 0.6% of borax crystal stabilizer by mass of the steel slag into a high-energy ball mill, grinding to a specific surface area of ≥450 m 2 / kg, and CaO content ≥40%, MgO content ≤5%, finally obtaining a high-activity, high-stability, and composition-controllable steel slag powder product, which provides the core cementing activity for the tailings solidification agent.

[0061] In this embodiment, the calcined red mud is prepared by using Bayer process red mud and two-stage calcination:

[0062] In the first stage, the temperature is raised to 450°C at a rate of 10°C / min and kept for 30 min. The core objective of this stage is to remove the crystal water in the red mud;

[0063] In the second stage, the temperature is raised to 750°C at a rate of 5°C / min and kept for 2 h. The core objective of this stage is to remove the alkali metal oxides in the red mud, and finally the Fe2O3 content is ≥25%, the Na2O content is ≤2.5%, and the specific surface area is ≥300 m 2 / kg;

[0064] After two-stage calcination, the specific surface area of the red mud is increased, significantly increasing the contact area with the steel slag powder, phosphogypsum, and other cementitious materials.

[0065] Referring to Figure 1The embodiment also provides a preparation method of tailings efficient solidifying agent in underground mine filling mining method, comprising the following steps:

[0066] Step one, pretreatment activation

[0067] Each raw material is weighed according to the weight ratio of each raw material above, and is prepared for standby. The calcined red mud and the phosphogypsum are mixed according to a mass ratio of 2:1, 10wt% citric acid solution accounting for 5% of the total mass of the two is added, and the mixture is stirred in a double-shaft stirrer (rotating speed 80 rpm) for 40 min, so that the alkali metal ions (Na + , K + ) in the red mud are complexed with citric acid, and part of the dihydrate gypsum in the phosphogypsum is converted into hemihydrate gypsum.

[0068] Step two, composite grinding and carbonization

[0069] The mixture obtained in step one and the steel slag micro-powder and fly ash are jointly put into a closed vertical mill (feed particle size ≤10 mm), the grinding medium is a steel ball with a diameter of 5 mm, the filling rate is 40%, food-grade CO2 gas (purity ≥99.9%) is introduced into the closed vertical mill at a flow rate of 0.8 L / min during the grinding process, the CO2 concentration in the closed vertical mill is maintained at 20% (volume fraction), the grinding time is controlled to be 30 min, the discharge temperature is ≤80℃, so that the residual f-CaO in the steel slag reacts with CO2 to generate nano CaCO3 crystal nucleus (particle size ≤100 nm), the carbonation conversion rate of the residual f-CaO in the steel slag is ≥85%, and the dispersity of the generated nano CaCO3 crystal nucleus in the powder is ≥90%.

[0070] Step three, preparation of nano modifier

[0071] The nano silicon dioxide with a particle size of 50 nm and the silane coupling agent KH-550 are weighed according to a mass ratio of 4:1, an ethanol-water mixed solvent (ethanol:water volume ratio=3:1) is added, and ultrasonic dispersion (frequency 40 kHz, power 500 W) is performed for 20 min to form a uniform dispersion liquid;

[0072] The dispersion liquid is dried by rotary evaporation at 80℃, and then ground to no hard agglomeration to obtain a surface-modified nano reinforcing agent;

[0073] Step four, homogenization and compounding

[0074] The powder obtained in step two (specific surface area ≥400 m² / kg), the nano reinforcing agent obtained in step three, and the chemical activator are put into a high-efficiency three-dimensional mixer (rotating speed 80 rpm), and mixed for 15 min until uniform, so as to obtain the finished solidifying agent.

[0075] The above merely provides the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A tailings high-efficiency consolidation agent in underground mine filling mining method, characterized in that, The cementitious base material, the nano-enhancing agent, the chemical activator and the organic fiber reinforcing agent are respectively 35-50 parts, 5-8 parts, 2-5 parts and 0.5-1.5 parts by weight. The cementitious base material is prepared by mixing steel slag powder, calcined red mud, phosphogypsum and fly ash in a mass ratio of (3-3.5):(1.5-2):1:(4-6). The nano-enhancing agent is nano-silica surface-modified by silane coupling agent KH-550, and the mass ratio of the silane coupling agent KH-550 to the nano-silica is (3.5-4.5):

10. The chemical activator is prepared by compounding anhydrous sodium sulfate and industrial-grade triethanolamine in a mass ratio of (4-6):(1.5-2.5). The organic fiber reinforcing agent is selected from one of polypropylene fiber or polyvinyl alcohol fiber, and the surface is etched by NaOH solution.

2. The tailings high-efficiency consolidation agent in the underground mine filling mining method according to claim 1, characterized in that: The specific preparation method of the steel slag powder is as follows: first, the converter steel slag is crushed, and then calcined in a rotary kiln to eliminate free iron oxide, followed by water quenching, and then the steel slag powder is prepared by adding 0.4-0.6% borax crystal stabilizer to the steel slag in a high-energy ball mill.

3. The tailings high-efficiency consolidation agent in an underground mine filling mining method according to claim 1, characterized in that: The specific preparation method of the calcined red mud is as follows: the Bayer process red mud is calcined in two stages, the first stage is to heat to 400-450℃ at a rate of 8-10℃ / min, and keep for 20-30min to remove crystal water, and the second stage is to heat to 650-750℃ at a rate of 3-5℃ / min, and keep for 1-2h to remove alkali, to obtain the calcined red mud product.

4. The tailings high-efficiency consolidation agent in an underground mine filling mining method according to claim 1, characterized in that: The SO3 content of the phosphogypsum is ≥35%, and the particle size D90 is ≤45μm.

5. The tailings high-efficiency consolidation agent in an underground mine filling mining method according to claim 1, characterized in that: The fly ash is low-calcium fly ash, and the total content of SiO2+Al2O3+Fe2O3 is ≥75%.

6. The tailings high-efficiency consolidation agent in an underground mine filling mining method according to claim 1, characterized in that: The purity of the anhydrous sodium sulfate in the chemical activator is ≥99.5%, and the purity of the industrial-grade triethanolamine is ≥88%.

7. The preparation method of the tailings high-efficiency consolidation agent applied to the underground mine filling mining method according to any one of claims 1-6, characterized in that, The method comprises the following steps: Step one: each raw material is weighed according to the preset weight ratio, the calcined red mud and the phosphogypsum are mixed first, then 10wt% citric acid solution is added to the mixture, accounting for 3-5% of the total mass of the calcined red mud and the phosphogypsum, and the mixture is stirred in a double-shaft mixer, so that the alkali metal ions in the calcined red mud are complexed with the citric acid, and part of the dihydrate gypsum in the phosphogypsum is converted into hemihydrate gypsum, to obtain a mixture; Step two: the mixture, the steel slag powder and the fly ash are put into a closed vertical mill for grinding, and food-grade CO2 gas is introduced during the grinding process, so that the residual free iron oxide in the steel slag reacts with CO2 to form nano-CaCO3 crystal nucleus, to obtain a powder; Step three: the nano-silica and the silane coupling agent KH-550 are added to an ethanol-water mixed solvent, and then ultrasonic dispersion treatment is performed to form a uniform dispersion liquid, the dispersion liquid is evaporated and dried, and then the surface-modified nano-enhancing agent is prepared by grinding; Step four: the powder obtained in step two, the nano-enhancing agent obtained in step three and the chemical activator are put into a high-efficiency three-dimensional mixer for mixing, and the tailings efficient solidification agent is obtained after uniform mixing.

8. The preparation method of the tailings high-efficiency consolidation agent in the underground mine filling mining method according to claim 7, characterized in that: In the second step, the flow rate of the CO2 gas is 0.5-1 L / min, the CO2 concentration in the mill is maintained at 15-20%, the grinding medium of the closed vertical mill is a steel ball with a diameter of 2-5 mm, and the filling rate is 35-40%.

Images