Preparation method of quick-solidification micro-expansion mine filling material and continuous filling process

Abstract

The application discloses a kind of preparation method and continuous filling process of quick solidification micro-expansion mine filling material, and is related to filling material technical field.The preparation method includes the following steps: cement, gypsum, early strength agent, accelerator, expanding agent, calcium formate, sodium gluconate and polypropylene fiber are mixed to obtain mixed dry materials;The mixed dry materials are mixed with water to obtain slurry;Foam generated by foaming liquid is introduced into the slurry to obtain foam concrete slurry;The foam concrete slurry is shaped, cured to obtain the quick solidification micro-expansion mine filling material.The quick solidification micro-expansion mine filling material prepared by the application has excellent water resistance and mechanical properties.Due to the filling of foam and the expansion of expanding agent, the quick solidification micro-expansion mine filling material prepared by the application also has low density, which can reduce the demand for filling materials during filling, thereby reducing the filling cost.

Description

Technical Field

[0001] This invention relates to the field of filling materials technology, and in particular to a method for preparing a rapid solidification micro-expansion mineral filling material and a continuous filling process. Background Technology

[0002] In mining operations, effective backfilling of goaf areas is a crucial measure to ensure underground safety, control ground pressure hazards, and reduce surface subsidence. Currently, the commonly used backfilling materials in the industry mainly include cement-based pastes, high-concentration tailings binders, and waste rock, while supporting processes involve paste pumping, tailings thickening conveying, or dry backfilling of waste rock. However, existing backfilling materials and processes still have a series of significant shortcomings, severely restricting the backfilling effect and economic benefits.

[0003] Firstly, regarding backfill materials, traditional cement-based materials are expensive, require large amounts of cement, and have slow early strength development, severely impacting stope connection and circulation efficiency. Secondly, high-concentration tailings backfill materials often suffer from poor fluidity, easy segregation and bleeding, and low durability, leading to high pipeline transport resistance, high risk of pipe blockage, and insufficient overall uniformity and stability of the resulting backfill. On the other hand, dry backfilling using aggregates such as waste rock suffers from problems such as incomplete roof connection and low density, failing to effectively suppress surrounding rock deformation.

[0004] Secondly, regarding the filling process, paste filling systems are complex, have extremely high power consumption and maintenance costs, and are difficult to control in terms of proportioning and rheological properties. In actual engineering, concentration fluctuations often cause transportation interruptions or uneven filling quality. Tailings filling processes, on the other hand, have stringent requirements for pretreatment stages such as thickening and mixing, and often cause underground environmental pollution and drainage burdens due to bleeding. In addition, most processes fail to achieve efficient coordination between filling and mining, resulting in long filling operation cycles that seriously affect the mine's continuous production capacity.

[0005] In summary, existing technologies struggle to balance cost and performance in filling materials, and the filling process is complex and lacks reliability. There is an urgent need to develop a new type of filling material and its supporting process that can reduce overall costs and improve process adaptability and automation while ensuring good fluidity, early strength, and final load-bearing capacity, thereby truly achieving safe, efficient, and economical goaf filling. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a rapidly solidifying, micro-expansion mine filling material and a continuous filling process to solve the problems existing in the prior art. This invention can significantly reduce costs and improve economic efficiency while taking into account the mechanical properties and water resistance of the filling material.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] One of the technical solutions of the present invention: a method for preparing a rapid solidification micro-expansion mine filling material, comprising the following steps:

[0009] Cement, gypsum, early-strength agent, quick-setting agent, expanding agent, calcium formate, sodium gluconate, and polypropylene fiber are mixed to obtain a mixed dry material; the mixed dry material is mixed with water to obtain a slurry; foam generated by foaming liquid is introduced into the slurry to obtain a foamed concrete slurry; the foamed concrete slurry is molded and cured to obtain the rapid-setting micro-expansion mining filling material.

[0010] In the filling material system of this invention, the components work together through precise synergistic effects to enhance material strength and optimize water resistance: the accelerator acts first, accelerating the hydration reaction and the formation of ettringite, causing the slurry to quickly lose its fluidity and establish an early skeleton structure; the early strength agent then intervenes, its molecules or reaction products providing a large number of crystal nuclei in the cement slurry, providing a site for the precipitation and crystallization of hydration products such as CSH gel and Ca(OH)2 crystals, while calcium formate assists in accelerating the hydration reaction, promoting the rapid solidification of the early skeleton to form high early strength, and calcium formate also has an anti-cracking effect; sodium gluconate, as a retarder, its sodium salt undergoes a complexation reaction with calcium ions to hinder hydration, and precisely regulates setting through its antagonistic effect with the accelerator. The timing of setting is crucial to avoid both instantaneous solidification of the slurry, which could hinder construction, and slow setting, which could delay strength development, ensuring a balance between the amount of ettringite generated in the early stages and the setting time. The expanding agent begins its work from the initial hydration stage, promoting ettringite formation and causing micro-expansion to compensate for the chemical shrinkage during early cement hydration and prevent early plastic shrinkage cracks. Furthermore, the ettringite itself is a strength phase that can continuously fill the internal pores of the material, improving structural density. Polypropylene fibers are uniformly dispersed in the slurry, effectively supporting aggregates, reducing bleeding, preventing early microcrack propagation, and enhancing material toughness. In addition, gypsum further optimizes the microstructural mechanical properties by generating needle-like ettringite to fill the CSH gel network structure. The synergistic effect of these components, from early skeleton construction and setting time control to later pore filling and crack inhibition, comprehensively improves the strength and water resistance of the filling material.

[0011] Furthermore, taking the sum of the masses of the cement and the gypsum as 100%, the mass percentage of the cement is 10-40%, and the mass percentage of the gypsum is 60-90%.

[0012] Preferably, the cement comprises sulfoaluminate cement.

[0013] Sulfoaluminate cement sets quickly, which can greatly reduce the construction period.

[0014] Preferably, the early strength agent includes chloride-based inorganic early strength agents.

[0015] Preferably, the mass of the early-strength agent is 0.2-1% of the mass of the cement.

[0016] More preferably, the mass of the early-strength agent is 1% of the mass of the cement.

[0017] Preferably, the accelerator includes a JC-A1 type accelerator.

[0018] Preferably, the mass of the accelerator is 4-6% of the mass of the cement.

[0019] More preferably, the mass of the accelerator is 6% of the mass of the cement.

[0020] Preferably, the expanding agent comprises an AEA-type expanding agent.

[0021] AEA-type expanding agent not only has a good expanding effect, but is also green and safe, with no environmental hazards.

[0022] Preferably, the mass of the AEA-type expansive agent is 4-12% of the mass of the cement.

[0023] More preferably, the mass of the AEA-type expansive agent is 4% of the mass of the cement.

[0024] Preferably, the mass of the calcium formate is 0.5-1.5% of the mass of the cement.

[0025] More preferably, the mass of the calcium formate is 0.5% of the mass of the cement.

[0026] Calcium formate can effectively reduce microcracks in filling materials and improve their compressive strength.

[0027] Preferably, the mass of the sodium gluconate is 0.2-1% of the mass of the cement.

[0028] Sodium gluconate can control the setting time, provide sufficient filling time, and reduce the phenomenon of grout sticking to the pipe wall during grout pouring.

[0029] Preferably, the mass of the polypropylene fiber is 0.5-1% of the mass of the cement.

[0030] Preferably, the mass of the water is 35-60% of the sum of the masses of the cement and the gypsum (i.e., the water-cement ratio is 0.35-0.6).

[0031] Furthermore, the foaming liquid is a mixture of K12 (sodium lauryl sulfate), FM500G (alcohol ether modified polyhydroxy polymer foam stabilizer), CAB-35 (cocamidopropyl betaine) and water.

[0032] Preferably, the mass ratio of K12, FM500G and CAB-35 is 6:1:0.8.

[0033] Preferably, the sum of the masses of K12, FM500G, and CAB-35 is 0.8% of the mass of the water.

[0034] The functions of each component in the foaming liquid of this invention are as follows:

[0035] K12 is a dominant foaming agent and an anionic surfactant. In the foaming liquid system, it plays two main roles: (1) Reducing surface tension: When K12 molecules are added to water, their hydrophobic tails rush towards the gas-liquid interface (the junction of air and water) to escape the water environment, arranging themselves neatly with the hydrophilic head remaining in the water and the hydrophobic tail extending towards the air. This directional arrangement significantly disrupts the strong attraction between water molecules, thus significantly reducing the surface tension of the water. With reduced surface tension, air is more easily trapped in the liquid, forming bubbles. (2) Forming and stabilizing foam: A large number of K12 molecules rapidly surround the gas with their hydrophobic tails facing the air and their hydrophilic heads facing the water, forming a monolayer and thus an initial spherical bubble. When two bubbles meet, the liquid wall between them is actually composed of two K12 molecular films, with the hydrophobic tails facing each other and the hydrophilic heads facing the water phases on both sides. This sandwich structure is called a "liquid film." The hydrophilic head of K12 carries a negative charge (-OSO3). - When they are arranged on the surface of the liquid film, like charges repel each other. This repulsive force can give the liquid film strength and elasticity, preventing bubbles from merging (coalescing) or breaking when they collide, thus stabilizing the foam.

[0036] FM500G primarily functions to stabilize foam. As a highly efficient water-soluble polymer, it significantly slows down the foam's rupture, coalescence, and coarsening processes by increasing the viscosity of the foam liquid film, forming an elastic protective layer, and inhibiting the drainage of liquid between bubbles, resulting in a finer, more stable, and longer-lasting foam structure.

[0037] CAB-35 primarily increases viscosity, resulting in denser foam. This is mainly achieved through its unique molecular structure and ionic properties, which create a strong synergistic interaction with K12. While thickening, it also acts as a mild surfactant, improving the mildness and foam stability of the main system.

[0038] Therefore, the synergistic effect of K12, FM500G and CAB-35 gives the foaming liquid of the present invention the advantages of high foaming ratio, good foam stability and low water bleeding rate.

[0039] Preferably, the amount of foam introduced into the slurry is 300 mL / 1000 g of mixed dry material (mixed dry material refers to the mass of mixed dry material contained in the slurry).

[0040] Preferably, the foam generated by the foaming liquid is introduced into the slurry and then rapidly stirred (at a speed of 80 rpm) to mix it.

[0041] The foaming liquid is foamed in the foaming device until it forms uniform and dense foam with a foaming ratio of 16 times. It is then immediately introduced into the slurry and quickly stirred. The rapid stirring can cause the foam to foam again after it bleeds water, ensuring the foam content in the foamed concrete slurry.

[0042] Preferably, the preparation method of the rapidly solidifying micro-expansion mineral filling material includes the following more specific steps:

[0043] (1) At room temperature, mix cement, gypsum, early strength agent, quick setting agent, expansion agent, calcium formate and sodium gluconate, stir for 2-5 minutes, then add polypropylene fiber and stir at 20 rpm for 2-5 minutes to obtain mixed dry material.

[0044] (2) Add water to the dry mixture at a water-cement ratio of 0.35-0.6 and stir at 20 rpm for 2-5 minutes to obtain a uniform slurry;

[0045] (3) The foaming liquid is foamed through a foaming device until a uniform and dense foam is formed and the foaming ratio reaches 16 times. The foam generated by foaming is introduced into the uniform slurry (the amount introduced is 300mL / 1000g of mixed dry material), and then stirred at 80rpm for 2-5min to make the foam and slurry completely mixed to obtain foamed concrete slurry.

[0046] (4) The foamed concrete slurry is molded and cured to obtain a rapidly solidified micro-expansion mining filling material.

[0047] The second technical solution of the present invention: a rapid solidification micro-expansion mine filling material prepared according to the above-mentioned preparation method of rapid solidification micro-expansion mine filling material.

[0048] The third technical solution of the present invention: a continuous filling method for a rapidly solidifying micro-expansion mine filling material, comprising the following steps:

[0049] Cement, gypsum, accelerator, quick-setting agent, expanding agent, calcium formate, sodium gluconate, and polypropylene fiber are mixed in a dry material mixing device to obtain a mixed dry material. Water is added to the mixed dry material in the dry material mixing device through a water adding device, and the mixture is stirred evenly to obtain a slurry. Foaming liquid is foamed in a foaming device, and the foam generated is introduced into the slurry to obtain foamed concrete slurry. The foamed concrete slurry is discharged through a pipeline and directly injected into the location to be filled for molding and curing, so as to achieve continuous filling of the rapidly solidifying micro-expansion mining filling material.

[0050] Preferably, the continuous filling method for the rapidly solidifying micro-expansion mine filling material includes the following more specific steps:

[0051] (1) At room temperature, cement, gypsum, early strength agent, quick setting agent, expansion agent, calcium formate and sodium gluconate are mixed in a dry material mixing device and stirred for 2-5 minutes. Then polypropylene fiber is added and stirred at 20 rpm for 2-5 minutes to obtain mixed dry material.

[0052] (2) Add water to the mixed dry material in the dry material mixing device according to the water-cement ratio of 0.35-0.6, and stir at 20 rpm for 2-5 minutes to obtain a uniform slurry;

[0053] (3) The foaming liquid is foamed through a foaming device until a uniform and dense foam is formed and the foaming ratio reaches 16 times. The foam generated by foaming is introduced into the uniform slurry (the amount introduced is 300mL / 1000g of mixed dry material), and then stirred at 80rpm for 2-5min to make the foam and slurry completely mixed to obtain foamed concrete slurry.

[0054] (4) The foamed concrete slurry is discharged through the pipeline and directly injected into the location to be filled for molding and curing, so as to realize the continuous filling of the rapid solidification micro-expansion mining filling material.

[0055] The above method employs a three-in-one-out continuous filling system (three inlets refer to the inlet of dry materials such as cement, water, and foam, and one outlet refers to the outlet of foamed concrete slurry) for the continuous preparation and filling of filling materials. This ensures the continuity of filling and greatly improves filling efficiency, allowing for the filling of 120m³ per hour. 3 and above.

[0056] The present invention discloses the following technical effects:

[0057] The rapid solidification micro-expansion mine filling material prepared by this invention has excellent water resistance and mechanical properties.

[0058] Due to the filling effect of foam and the expansion effect of the expanding agent, the rapid solidification micro-expansion mine filling material prepared by this invention also has a low density, which can reduce the amount of filling material required during filling and thus reduce the filling cost.

[0059] The preparation method and continuous filling process of the rapid solidification micro-expansion mine filling material of the present invention have the advantages of faster solidification speed, stronger filling continuity and higher degree of mechanization. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 The results are the uniaxial compressive strength test results of the rapid solidification micro-expansion mine filling material samples prepared in Examples 1-3.

[0062] Figure 2 The results show the water resistance test results of the rapid solidification micro-expansion mine filling material samples prepared in Examples 1-3.

[0063] Figure 3 The image shows the XRD pattern of the rapid solidification micro-expansion mineral filling material sample prepared in Example 1.

[0064] Figure 4 The image shows the XRD pattern of the rapid solidification micro-expansion mineral filling material sample prepared in Example 2.

[0065] Figure 5 The image shows the XRD pattern of the rapid solidification micro-expansion mineral filling material sample prepared in Example 3.

[0066] Figure 6 EDS image of the rapid solidification micro-expansion mineral filling material sample prepared in Example 1.

[0067] Figure 7 EDS image of the rapid solidification micro-expansion mineral filling material sample prepared in Example 2.

[0068] Figure 8 The images show the foam just prepared from the foaming liquid made by mixing K12, FM500G, CAB-35 and water, and the foam after a 1-hour water seepage test. (a) shows the foam just prepared, and (b) shows the foam after a 1-hour water seepage test.

[0069] Figure 9The images show the foam just prepared from the foaming liquid made of SDBS, FM500G, CAB-35 and water, and the foam after a 1-hour water seepage test. (a) shows the foam just prepared, and (b) shows the foam after a 1-hour water seepage test.

[0070] Figure 10 Photographs taken 20 minutes after a foaming solution made from a mixture of AOS, FM500G, CAB-35 and water was tested for water leakage.

[0071] Figure 11 The images show the foam just prepared from the foaming liquid made by mixing K12, FM500, CAB-35 and water, and the foam after a 40-minute water seepage test. (a) shows the foam just prepared, and (b) shows the foam after a 40-minute water seepage test.

[0072] Figure 12 The images show the foam just prepared from the foaming liquid made by mixing K12, FM500G and water, and the foam after a 10-minute water seepage test. (a) shows the foam just prepared, and (b) shows the foam after a 10-minute water seepage test. Detailed Implementation

[0073] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0074] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0075] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0076] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0077] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0078] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0079] In the following embodiments and comparative examples of the present invention, room temperature refers specifically to 20-30°C.

[0080] Unless otherwise specified, all raw materials used in the following embodiments and comparative examples of this invention are commercially available products. Among them, the sulfoaluminate cement is R.SAC42.5 grade sulfoaluminate cement; the gypsum is desulfurized gypsum (calcium sulfate dihydrate content is 92wt%); the early strength agent is calcium chloride; the quick-setting agent is JC-A1 type quick-setting agent; and the expansion agent is AEA type expansion agent.

[0081] Example 1

[0082] A rapid-solidification micro-expansion mineral filling material is prepared by the following steps:

[0083] (1) At room temperature, mix 100g sulfoaluminate cement, 900g gypsum, 1g early strength agent, 6g quick setting agent, 4g expansion agent, 0.5g calcium formate and 1g sodium gluconate, stir at 20 rpm for 2 min, then add 1g polypropylene fiber, stir at 20 rpm for 2 min to obtain mixed dry material.

[0084] (2) Add water to the dry mixture at a water-cement ratio of 0.45 and stir at 20 rpm for 3 minutes to obtain a uniform slurry.

[0085] (3) The foaming liquid (made of K12, FM500G, CAB-35 and water, wherein the mass ratio of K12, FM500G and CAB-35 is 6:1:0.8 and the sum of the mass of K12, FM500G and CAB-35 is 0.8% of the mass of water) is foamed through a foaming device until a uniform and dense foam is formed and the foaming ratio reaches 16 times. The foam generated by foaming is introduced into the uniform slurry (the amount introduced is 300mL / 1000g of mixed dry material), and then stirred at 80rpm for 2min to make the foam and slurry completely mixed to obtain foamed concrete slurry.

[0086] (4) Fill the foamed concrete slurry into the mold (5cm×5cm×5cm) and mold it. After 2 hours, demold it and cure it for 3 days or 28 days (the standard curing conditions are: temperature 20±1℃ and humidity 95±1%) to obtain rapid solidification micro-expansion mine filling material samples with different curing times for testing.

[0087] Example 2

[0088] A rapid-solidification micro-expansion mineral filling material is prepared by the following steps:

[0089] (1) At room temperature, mix 150g sulfoaluminate cement, 850g gypsum, 1.5g early strength agent, 9g quick setting agent, 6g expansion agent, 0.75g calcium formate and 1g sodium gluconate, stir at 20 rpm for 2 min, then add 1g polypropylene fiber, stir at 20 rpm for 2 min to obtain mixed dry material.

[0090] (2) Add water to the dry mixture at a water-cement ratio of 0.45 and stir at 20 rpm for 3 minutes to obtain a uniform slurry.

[0091] (3) The foaming liquid (made of K12, FM500G, CAB-35 and water, wherein the mass ratio of K12, FM500G and CAB-35 is 6:1:0.8 and the sum of the mass of K12, FM500G and CAB-35 is 0.8% of the mass of water) is foamed through a foaming device until a uniform and dense foam is formed and the foaming ratio reaches 16 times. The foam generated by foaming is introduced into the uniform slurry (the amount introduced is 300mL / 1000g of mixed dry material), and then stirred at 80rpm for 2min to make the foam and slurry completely mixed to obtain foamed concrete slurry.

[0092] (4) Fill the foamed concrete slurry into the mold (5cm×5cm×5cm) and demold after 2 hours. After demolding, standard curing is performed for 3 days or 28 days to obtain rapid solidification micro-expansion mining filling material samples with different curing times for testing.

[0093] Example 3

[0094] A rapid-solidification micro-expansion mineral filling material is prepared by the following steps:

[0095] (1) At room temperature, mix 200g sulfoaluminate cement, 800g gypsum, 2g early strength agent, 12g quick setting agent, 8g expansion agent, 1g calcium formate and 1g sodium gluconate, stir at 20 rpm for 2 min, then add 1g polypropylene fiber, stir at 20 rpm for 2 min to obtain mixed dry material.

[0096] (2) Add water to the dry mixture at a water-cement ratio of 0.45 and stir at 20 rpm for 3 minutes to obtain a uniform slurry.

[0097] (3) The foaming liquid (made of K12, FM500G, CAB-35 and water, wherein the mass ratio of K12, FM500G and CAB-35 is 6:1:0.8 and the sum of the mass of K12, FM500G and CAB-35 is 0.8% of the mass of water) is foamed through a foaming device until a uniform and dense foam is formed and the foaming ratio reaches 16 times. The foam generated by foaming is introduced into the uniform slurry (the amount introduced is 300mL / 1000g of mixed dry material), and then stirred at 80rpm for 2min to make the foam and slurry completely mixed to obtain foamed concrete slurry.

[0098] (4) Fill the foamed concrete slurry into the mold (5cm×5cm×5cm) and demold after 2 hours. After demolding, standard curing is performed for 3 days or 28 days to obtain rapid solidification micro-expansion mining filling material samples with different curing times for testing.

[0099] Example 4

[0100] A continuous filling process for a rapidly solidifying micro-expansion mine filling material includes the following steps:

[0101] (1) At room temperature, 100g of sulfoaluminate cement, 900g of gypsum, 1g of early strength agent, 6g of quick-setting agent, 4g of expansion agent, 0.5g of calcium formate and 1g of sodium gluconate are mixed in a dry material mixing device and stirred at 20 rpm for 2 minutes. Then, 1g of polypropylene fiber is added and stirred at 20 rpm for 2 minutes to obtain the mixed dry material.

[0102] (2) Add water to the mixed dry material in the dry material mixing device according to the water-binder ratio of 0.45, and stir at 20 rpm for 3 minutes to obtain a uniform slurry;

[0103] (3) The foaming liquid (made of K12, FM500G, CAB-35 and water, wherein the mass ratio of K12, FM500G and CAB-35 is 6:1:0.8 and the sum of the mass of K12, FM500G and CAB-35 is 0.8% of the mass of water) is foamed through a foaming device until a uniform and dense foam is formed and the foaming ratio reaches 16 times. The foam generated by foaming is introduced into the uniform slurry (the amount introduced is 300mL / 1000g of mixed dry material), and then stirred at 80rpm for 2min to make the foam and slurry completely mixed to obtain foamed concrete slurry;

[0104] (4) The foamed concrete slurry is discharged through a pipeline and directly injected into the location to be filled for molding and curing, so as to achieve continuous filling of the rapidly solidifying micro-expansion mining filling material, with a filling volume of 120m³. 3 / h.

[0105] Comparative Example 1

[0106] A filling material, the preparation steps are as follows:

[0107] (1) At room temperature, mix 200g sulfoaluminate cement, 800g gypsum, 2g early strength agent, 12g quick setting agent, 8g expansion agent and 1g calcium formate, stir at 20rpm for 2min, then add 1g polypropylene fiber, stir at 20rpm for 2min to obtain mixed dry material.

[0108] (2) Water was added to the dry mixture at a water-cement ratio of 0.45. The dry mixture underwent a hydration reaction immediately upon adding water, and the surface of the dry mixture solidified rapidly. After stirring, the mixture solidified as a whole and failed to form a slurry.

[0109] Comparative Example 2

[0110] Same as Example 1, except that the use of calcium formate is omitted.

[0111] Test case

[0112] (1) Compressive strength test

[0113] The uniaxial compressive strength of the rapid-solidification micro-expansion mine filling material samples prepared in Examples 1-3 (curing time 28 days) was tested according to GB / T 50081-2019, and the results are as follows: Figure 1 As shown, it can be seen that the compressive strength (28d) of the rapid solidification micro-expansion mine filling material samples prepared in Examples 1-3 is all greater than 2MPa, and the compressive strength first increases and then decreases with the increase of cement content, that is, the compressive strength of Example 2 is the highest.

[0114] In addition, the compressive strength of the filling material samples (curing time of 3 days) prepared in Example 1 and Comparative Example 2 were tested using the same method. The results showed that the compressive strength of Example 1 was 1.306 MPa, while the 3-day compressive strength of Comparative Example 2 was only 0.437 MPa.

[0115] (2) Water resistance test

[0116] Water resistance tests were conducted on the rapid-setting micro-expansion mine backfill material samples prepared in Examples 1-3 (curing time: 28 days). Specifically, the backfill material samples were immersed in water at room temperature for 28 days, and then the uniaxial compressive strength was tested again. The results are as follows: Figure 2As shown in the figure, it can be seen that after soaking in water, the compressive strength of the rapid solidification micro-expansion mine filling material samples prepared in Examples 1-3 did not change much, indicating that they have good water resistance and can meet the complex environmental conditions underground.

[0117] (3) XRD test

[0118] XRD tests were performed on the rapid solidification micro-expansion mine filling material samples prepared in Examples 1-3, and the final composition of the filling material samples was analyzed using software. The results are as follows: Figure 3-5 As shown (where Figure 3 Example 1, Figure 4 Example 2, Figure 5 (See Example 3). It can be seen that the final composition of the filling material is mainly calcium sulfate dihydrate gel, which also contains some unreacted calcium carbonate impurities.

[0119] (4) EDS test

[0120] EDS analysis was performed on the rapid solidification micro-expansion mine filling material samples prepared in Examples 1-2 to analyze the elemental composition of the samples. The results are as follows: Figure 6-7 As shown (where Figure 6 Example 1, Figure 7 (Example 2). It can be seen that the elemental distribution in the filling material sample is uniform, indicating that the mixing is thorough and the hydration reaction between the materials is complete (the Zr may originate from impurities in each component).

[0121] (5) Foam performance test

[0122] The uniform and dense foam (expansion ratio of 16 times) formed by the foaming device in step (3) of Example 1 was tested for stability and water bleeding rate according to standard JC / T 2199-2013. The results showed that the foam basically did not dissipate after 2 hours at room temperature, and the water bleeding rate was 2 wt% after 1 hour. Photos of the freshly prepared foam and the foam after 1 hour of water bleeding testing are shown below. Figure 8 As shown, (a) is the foam that has just been prepared, and (b) is the foam after 1 hour of water seepage test.

[0123] In addition, to demonstrate the advantages of the foaming liquid in this invention, the following foaming liquids were prepared and their performance was compared with that of the foaming liquid of this invention (all performance tests were conducted in accordance with standard JC / T 2199-2013).

[0124] 1) The foaming solution was prepared by mixing SDBS (sodium dodecylbenzenesulfonate), FM500G, CAB-35, and water (the mass ratio of SDBS, FM500G, and CAB-35 was 6:1:0.8, and the sum of the masses of SDBS, FM500G, and CAB-35 was 0.8% of the mass of water). The foaming solution was used to generate uniform and dense foam using a foaming device. Testing showed a foaming ratio of 9 times and a water bleeding rate of 5 wt% after 1 hour. Photos of the freshly prepared foam and the foam after 1 hour of water bleeding testing are shown below. Figure 9 As shown, (a) is the foam that has just been prepared, and (b) is the foam after 1 hour of water seepage test.

[0125] 2) The foaming solution was prepared by mixing AOS (sodium α-alkenyl sulfonate), FM500G, CAB-35, and water in a mass ratio of 6:1:0.8:100 (wherein, the mass ratio of AOS, FM500G, and CAB-35 is 6:1:0.8, and the sum of the masses of AOS, FM500G, and CAB-35 is 0.8% of the mass of water). The foaming solution was foamed using a foaming device until a uniform and dense foam was formed. Testing showed a foaming ratio of 19 times, and complete water exudation occurred after 20 minutes. A photo of the water exudation test after 20 minutes is shown below. Figure 10 As shown.

[0126] 3) The foaming solution was prepared by mixing K12, FM500 (silicone polyether emulsion microemulsion MPS foam stabilizer), CAB-35, and water (the mass ratio of K12, FM500, and CAB-35 was 6:1:0.8, and the sum of the masses of K12, FM500, and CAB-35 was 0.8% of the mass of water). The foaming solution was used to generate uniform and dense foam using a foaming device. Testing showed a foaming ratio of 14 times, but significant water seepage occurred after 40 minutes, resulting in sparse foam. Photos of the freshly prepared foam and the foam after the 40-minute water seepage test are shown below. Figure 11 As shown, (a) is the foam that has just been prepared, and (b) is the foam after 40 minutes of water seepage test.

[0127] 4) The foaming solution is a mixture of K12, FM500G, and water (the mass ratio of K12 to FM500G is 6:1, and the sum of the masses of K12 and FM500G is 0.8% of the mass of water). This foaming solution is used to generate uniform and dense foam using a foaming device. Testing showed a foaming ratio of 26 times, and the foam dissolved into water after 10 minutes. Photos of the freshly prepared foam and the foam after a 10-minute water seepage test are shown below. Figure 12 As shown, (a) is the foam that has just been prepared, and (b) is the foam after 10 minutes of water seepage test.

[0128] Through comparison of different foaming liquids, it was found that the foaming liquid system of the present invention (K12+FM500G+CAB-35) has a high foaming ratio, good foam stability, and low water bleeding rate. Since foam performance directly affects the performance of filling materials, using the foaming liquid system of the present invention is more conducive to obtaining filling materials with high strength, high water resistance, and high stability.

[0129] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a rapidly solidifying, micro-expansion mineral filling material, characterized in that, Includes the following steps: Cement, gypsum, early strength agent, quick-setting agent, expanding agent, calcium formate, sodium gluconate and polypropylene fiber are mixed to obtain a mixed dry material; the mixed dry material is mixed with water to obtain a slurry; foam generated by foaming liquid is introduced into the slurry to obtain foamed concrete slurry; the foamed concrete slurry is molded and cured to obtain the rapid-setting micro-expansion mining filling material. With the total mass of the cement and the gypsum being 100%, the mass percentage of the cement is 10-40%, and the mass percentage of the gypsum is 60-90%. The mass of the early strength agent is 0.2-1% of the mass of the cement; The mass of the quick-setting agent is 4-6% of the mass of the cement; The mass of the expansion agent is 4-12% of the mass of the cement; The mass of the calcium formate is 0.5-1.5% of the mass of the cement; The mass of the sodium gluconate is 0.2-1% of the mass of the cement; The mass of the polypropylene fiber is 0.5-1% of the mass of the cement; The mass of the water is 35-60% of the sum of the masses of the cement and the gypsum; The amount of foam introduced into the slurry is 300 mL / 1000 g of mixed dry material; The foaming liquid is a mixture of K12, FM500G, CAB-35 and water; The mass ratio of K12, FM500G, and CAB-35 is 6:1:0.8; The sum of the masses of K12, FM500G, and CAB-35 is 0.8% of the mass of the water.

2. The preparation method of the rapid solidification micro-expansion mineral filling material as described in claim 1, characterized in that, The expanding agent includes AEA type expanding agent.

3. A rapidly solidifying micro-expansion mineral filling material prepared by the method according to any one of claims 1-2.

4. A continuous filling method for a rapidly solidifying micro-expansion mine filling material, characterized in that, Includes the following steps: Cement, gypsum, accelerator, quick-setting agent, expanding agent, calcium formate, sodium gluconate, and polypropylene fiber are mixed in a dry material mixing device to obtain a mixed dry material. Water is added to the mixed dry material in the dry material mixing device through a water adding device, and the mixture is stirred evenly to obtain a slurry. Foaming liquid is foamed in a foaming device, and the foam generated is introduced into the slurry to obtain foamed concrete slurry. The foamed concrete slurry is discharged through a pipeline and directly injected into the location to be filled for molding and curing, so as to achieve continuous filling of the rapidly solidifying micro-expansion mining filling material.

Images