Filling mining slurry rapid curing system and parameter confirmation method thereof

Abstract

The invention provides a filling mining slurry rapid curing system. The filling mining slurry rapid curing system comprises a slurry receiving subsystem, a curing subsystem and a rapid pumping subsystem. The slurry receiving subsystem comprises a slurry receiving bin and a slurry stirring device; the slurry receiving bin receives low-concentration filling slurry conveyed from the ground, and the slurry stirring device continuously stirs the slurry in the slurry receiving bin to prevent segregation; the slurry receiving bin and the slurry stirring device are matched together, so that the buffering and temporary storage effects are achieved, the pipe blocking accident caused by interruption of the preparation process of the ground slurry is avoided, and the continuous preparation and transmission effects on the slurry are achieved; the curing subsystem comprises a curing bin, and a thickening device, an additive adding device and a stirring device are arranged in the curing bin; and the maintenance subsystem is used for increasing the concentration of the slurry, accelerating the hydration reaction and curing process of the slurry, shortening the initial setting time of the slurry, and playing a role in separating and buffering slurry ground preparation and filling operation.

Description

Technical Field

[0001] The present disclosure relates to the technical field of coal mining paste filling, and in particular to a filling mining slurry rapid solidification system and a parameter confirmation method thereof. Background Art

[0002] Environmental protection and other issues associated with coal mining have always persisted. On the one hand, with the increase in coal mining intensity and the uneven distribution of coal resources, most coal mines in my country are facing the dilemma of exhaustion of recoverable resources and relatively abundant reserves of "three-down" coal, especially in the eastern mining areas; on the other hand, coal mining causes a large amount of gangue to accumulate on the ground, which not only occupies fertile land, but also causes environmental pollution. At the same time, coal mining causes the movement and destruction of rock strata, causing the migration of gas and water, resulting in frequent coal mine gas accidents and underground water inrush accidents; it causes groundwater loss, causing a sharp drop in groundwater levels, leading to water depletion in mining areas and destruction of surface vegetation; it causes a large surface subsidence, and arable land, building facilities, etc. are severely damaged; secondly, with the continuous exploitation of shallow coal resources and the continuous increase in mining depth, the frequency and intensity of dynamic disasters such as mine pressure and impact mine pressure have increased, seriously endangering the safe production of mines; thirdly, the emission and disposal of coal-based solid wastes such as coal gangue and fly ash are becoming more and more serious. At present, the comprehensive utilization rate of coal-based solid wastes is less than 50%.

[0003] Backfill mining technology is an effective method based on solving the above-mentioned various engineering problems from the source. Backfill mining utilizes solid waste and urban garbage generated during the mining process, crushes them into materials and then fills them into the goaf to reduce the range and amplitude of rock movement, thereby controlling surface subsidence. At the same time, solid waste such as gangue is utilized to avoid environmental pollution.

[0004] The filling mining technology of coal mines mainly includes solid filling and paste filling technology. Solid filling technology is to use mixed materials such as coal gangue and fly ash to be transported from the ground by shaft conveying equipment to the filling conveyor, and the filling materials are filled into the goaf through the discharge hole, and then the filling materials are compacted by the tamping device to achieve the mining technology of controlling rock movement and ground collapse. Paste filling technology refers to processing waste such as coal gangue and fly ash into aggregates of a certain size, and mixing them with cementing materials and water in a certain proportion to make slurry, which is transported from the ground through a filling pump, through a borehole and a pipeline to the goaf behind the working face. After the slurry solidifies, a support system mainly composed of gangue paste filling is formed. The surface deformation is controlled within the range allowed by the safety of buildings and infrastructure, and the ecological environment such as the aquifer structure is not affected.

[0005] Paste filling mining technology is an important part of filling mining. It is to crush solid waste such as coal gangue, and then add cement, fly ash, etc., and mix them with water in a specific proportion to form a paste slurry that does not require dehydration. The paste is transported to the underground filling goaf through a filling pump or a self-sliding pipeline. After it solidifies, it forms an effective support for the overlying rock strata, thereby controlling surface subsidence and protecting the ecological environment of the mining area.

[0006] The comprehensive mechanized paste filling coal mining process is as follows: a) Use an integral filling coal mining hydraulic support to carry out coal mining operations first; (b) When the working face advances to the set filling step distance (generally 3 to 7 meters), the isolation process is carried out. Each cycle forms an independent filling area, which is isolated by plastic cloth to isolate the area to be filled and the coal mining area; (c) The ground surface slurry preparation system mixes and stirs the filling materials according to the required material composition and ratio, and then transports them to the underground through a pipeline to fill the goaf behind the hydraulic support with paste. After the paste filling slurry solidifies, the next cycle of coal mining operations will be carried out. Its technical principles and system layout are as follows: Figure 3 As shown, the schematic diagram after the construction is completed is as follows Figure 4 shown.

[0007] After the paste filling material solidifies, the filling body and the surrounding rock form a support system to jointly bear the overburden load and mining stress, so as to achieve surface subsidence control and protect the ecological environment of the mining area. It has the following main characteristics: (a) After the filling material solidifies, the filling body has high strength, high filling rate, good ground subsidence reduction effect, and good protection effect on the ecological environment of the mining area; (b) It can realize the effective utilization of solid waste filling, liberate land resources, and significantly reduce the impact of mining on the ecological environment of the mining area; (c) It changes the control method of the mining site roof and surrounding rock, effectively avoids the superposition of mining stress, improves the safety of the mine, and can effectively prevent and control the occurrence of accidents such as mine water disasters and impact ground pressure; (d) It can significantly improve the recovery rate and cleanliness of coal resources, greatly reduce the impact of mining on surface buildings, and avoid social conflicts caused by tension between workers and peasants; (e) Paste filling materials can be obtained locally and have a wide range of sources. Materials are transported by pipelines, which has high technical requirements and is difficult to control;

[0008] In short, paste filling mining technology can realize the organic combination of the existing production system of the mine, the ecological environment governance and protection of the mining area, and the development of the mining area. It can not only ensure the full and safe recovery of coal resources, but also realize the comprehensive utilization of solid wastes such as coal gangue and fly ash. It has a wide range of applications, especially for mines with dense populations, dense buildings, and high requirements for subsidence control. Its main process flow is as follows: Figure 2 As shown,

[0009] However, at present, paste filling technology is limited by the long filling operation time and slow slurry solidification speed, and can no longer meet the requirements of high production efficiency of coal mining faces. The main problems and challenges include:

[0010] (1) The backfilling coal mining system has many pieces of equipment and complex procedures. It is difficult to synchronize and coordinate the ground slurry preparation system and the underground backfilling system. For example, sometimes the ground slurry has been prepared and transported underground, but the operation site encounters an emergency and does not have the conditions for backfilling, resulting in frequent pipe blockages.

[0011] (2) Coal seam mining conditions vary. For example, coal seams have uneven thickness and inclination. The amount of slurry required for each filling process is difficult to control and fluctuates greatly, making accurate filling difficult.

[0012] (III) The performance requirements of filling materials are high. They must have good fluidity and transportability, as well as a certain concentration and strength that meets the requirements after solidification. There is a contradiction between the two.

[0013] (IV) The most important thing is that the filling material solidifies slowly. Filling mining requires that the slurry solidifies and has a certain strength and bearing capacity before the working face can start coal mining operations, resulting in a long waiting time for the slurry to solidify. According to statistics, the coal production capacity of the filling working face is only 1 / 5 to 1 / 3 of that of the working face with the same conditions, making it difficult to generate economic benefits. This is also the main reason why the filling coal mining process is difficult to promote on a large scale.

[0014] (V) The filling pipelines above and below the well are long, the pipeline resistance is large, the slurry is transported from the ground to the well, the continuous pumping time is long, and the efficiency is low.

[0015] (6) Once the filling operation becomes stuck and the slurry segregates, pipe blockage is very likely to occur, which is difficult to handle.

[0016] (VII) After each filling process is completed, the pipeline needs to be cleaned. The process is complicated, the water consumption is large and the wastewater discharge is difficult.

[0017] There is currently no good solution on the market for this. Summary of the invention

[0018] In response to the above technical problems in the related art, the present disclosure proposes a rapid solidification system for filling mining slurry that can screen out products within the required power range before installation and can control constant power, which can overcome the above shortcomings of the prior art.

[0019] To achieve the above technical objectives, the technical solution of the present disclosure is implemented as follows:

[0020] The first object of the present disclosure is to provide a rapid solidification system for backfill mining slurry, comprising a slurry receiving subsystem, a curing subsystem and a rapid pumping subsystem connected in sequence;

[0021] The first object of the present disclosure is to provide a rapid solidification system for backfill mining slurry, comprising a slurry receiving subsystem, a curing subsystem and a rapid pumping subsystem connected in sequence;

[0022] The slurry receiving subsystem includes a slurry receiving bin and a slurry stirring device that cooperate with each other; the slurry receiving bin receives low-concentration filling slurry transmitted from the ground, and the slurry stirring device continuously stirs the slurry in the slurry receiving bin to prevent segregation; the slurry receiving bin and the slurry stirring device cooperate with each other to achieve buffering and temporary storage, avoid interruption of the ground surface slurry preparation process and cause pipe blockage accidents, and achieve continuous preparation and transmission of slurry;

[0023] The curing subsystem includes a curing bin, which is equipped with a thickening device, an admixture adding device and a stirring device; the curing subsystem is used to increase the concentration of the slurry, accelerate the hydration reaction and curing process of the slurry, shorten the initial setting time of the slurry, and play a role in separating and buffering the slurry ground preparation and filling operations; the admixture adding device adds admixtures to the curing bin to improve the fluidity of the slurry; the thickening device removes excess water from the slurry, increases the concentration of the slurry, and shortens the curing time of the slurry;

[0024] The rapid pumping subsystem includes a filling pump, a microwave generator, and a transmission pipeline. The filling pump and the large-diameter pipeline together transport and pump the slurry over a short distance. The microwave generator generates microwaves and introduces them into the transmission pipeline. The microwaves heat the transported slurry and accelerate the hydration reaction.

[0025] Preferably, the input end of the slurry receiving bin is connected to the filling material mixing station on the ground, the input end of the curing bin is connected to the output end of the slurry receiving bin, the output end of the curing bin is connected to the input end of the filling pump, the output end of the filling pump is connected to the input end of the transmission pipeline, the transmission pipeline leads to the filling working surface, and a valve is provided on the transmission pipeline. The filling material mixing station is set on the ground.

[0026] Preferably, the admixture comprises a flocculant.

[0027] Preferably, the thickening device removes excess moisture, which, depending on actual needs, is preferably set at 10% to 20% of the total moisture in the curing bin.

[0028] Preferably, the thickening device preferably adopts a thickener. The thickener is a solid-liquid separation device based on gravity sedimentation, and its appearance is a cylindrical shallow tank with a conical bottom. With the help of a rake installed in the thickener and running slowly (1 / 2 to 1 / 6 r / min), the paste-containing slurry can be input into the thickener from the upper port, concentrated into a high-concentration slurry through gravity sedimentation, and the thickened underflow slurry is discharged from the underflow port at the bottom of the thickener.

[0029] Preferably, the filling pump is a high-power filling pump, and the conveying pipeline is a large-diameter pipeline.

[0030] Preferably, the conveying pipe is a double-layer hollow structure.

[0031] Preferably, the double-layer hollow structure of the conveying pipeline includes an inner tube and an outer tube, and a hollow area is between the inner tube and the outer tube; the inner tube is used to convey the slurry; microwaves are introduced into the hollow area to heat the tube wall of the inner tube and the slurry.

[0032] Preferably, the tube wall of the outer tube is treated with anti-microwave leakage treatment to avoid microwave leakage and ensure that microwaves are only transmitted inside the transmission pipeline, thereby improving the heating efficiency of the inner tube and slurry by microwaves.

[0033] The second object of the present disclosure is to provide a parameter confirmation method for a filling mining slurry rapid solidification system, which comprises the following steps:

[0034] S1 determines the curing bin capacity: the curing bin capacity Q c The following formula is used for calculation:

[0035]

[0036] In formula 1: k1——unbalanced mining and charging coefficient;

[0037] k2——filling expansion coefficient;

[0038] p c ——Bulk density of slurry, in t / m 3 ;

[0039] p m ——Bulk density of mined raw coal, in t / m 3 ;

[0040] Q m ——The amount of raw coal mined at the maximum filling step, in tons;

[0041] (Supplementary explanation: In the process of determining the capacity of the curing bin, the filling and mining working face adopts the cycle of "coal mining-filling-coal mining-filling". The working face is filled once after every few cuts of coal (i.e., the filling step). After it is full, the next coal mining cycle is carried out after the filling body solidifies. In order to form a closed filling space in the goaf, the method of hanging bags behind the support is adopted to fill the bags with slurry. The filling slurry is pumped out from the curing bin. Therefore, the capacity of the curing bin should not be less than one filling step, and a certain mining and filling imbalance coefficient K1 should be considered).

[0042] S2 Thickening device dehydration: When the slurry enters the curing subsystem, the thickening device is automatically controlled according to the initial state of the slurry and the dehydration amount during the dehydration and thickening process, and the excess water W that needs to be removed by thickening is calculated using the following formula 2:

[0043]

[0044] In formula 2: C1 – the initial concentration of the slurry is first tested when it enters the curing subsystem;

[0045] C2 - target concentration of slurry after dehydration using thickener;

[0046] V——-The amount of slurry that needs to be thickened to remove excess water;

[0047] W - the amount of excess water that needs to be stripped off;

[0048] S3 Determine the amount of admixture added: In the curing bin, add admixtures through the admixture adding device, and continuously stir the slurry through the stirring device. Use a viscometer to test the viscosity of the slurry every 10 minutes; when the slurry viscosity μ satisfies the following formula 3, stop adding:

[0049] μ≥4.4×10 -4 vρ c r(Formula 3);

[0050] In formula 3: μ——slurry viscosity;

[0051] V——slurry pumping velocity, m / s;

[0052] P c—— Indicates the bulk density of slurry, t / m 3 ;

[0053] r - outer diameter of the transmission pipeline;

[0054] S4 stirring and standing: the slurry is thickened and dehydrated by the thickening device to increase the concentration, then the admixture is added for full stirring, and then the slurry is stood for hydration reaction, and the standing time is less than or equal to 2h, h——hours;

[0055] During the static period, the slurry was sampled every 10 minutes, and the rheological properties of the slurry were tested using an automatic rheometer. When the maximum shear stress of the slurry reached 3000Pa, the pumping conditions were met.

[0056] S5 Determine the filling pump power: The filling pump power is calculated by the following formula 4;

[0057]

[0058] In the formula: P1——indicates the filling pump power, in W;

[0059] P c ——Indicates the bulk density of the slurry, in t / m 3 ;

[0060] g——indicates the acceleration due to gravity;

[0061] Q——indicates flow rate, in m 3 / s;

[0062] l——indicates the conveying distance, in meters;

[0063] η——indicates the efficiency of the filling pump;

[0064] S6 confirms the microwave generator power: the microwave generator power P2 is calculated using the following formula 5;

[0065]

[0066] In formula 5:

[0067] P2- represents the microwave generator power, unit is W;

[0068] Q——indicates flow rate, in m 3 / s;

[0069] P c ——-Indicates the bulk density of slurry;

[0070] λ——indicates microwave frequency;

[0071] R——Inner diameter of the outer tube wall;

[0072] r ——is the outer diameter of the inner tube wall;

[0073] Compared with the prior art, the present invention achieves the following beneficial effects: (A) Most of the hydration reactions are completed in the curing tank, which saves the need for hydration reaction after filling and greatly shortens the solidification time; (B) Pipe blockage will not occur, and the slurry can be pumped into the well at a lower concentration, and then undergo secondary thickening treatment in the curing tank, avoiding pipe blockage in high-concentration slurry well sites; (C) The curing bin is located underground and is close to the filling point, so a large-diameter, high-flow pumping method can be used, and the filling efficiency is high; (D) The ground surface slurry can be pumped into the underground curing tank continuously without flushing the pipeline; (E) The slurry transportation time and the solidification time after filling are greatly shortened, the operation process and pipe blockage phenomenon are simplified, and the coal mining operation efficiency of the filling working face is improved; (F) Microwave instant heating is used to accelerate the hydration reaction and shorten the initial setting time.

[0074] In general, in backfill mining, the hydration reaction begins only after the slurry is pumped to the working face, and it takes 12-24 hours to reach initial setting, and the working face cannot be produced during this period. The initial setting time of the present invention is shortened to 4-6 hours, which is only 1 / 3 of the usual time.

[0075] In the present disclosure, the rapid pumping subsystem mainly includes a filling pump, a microwave generator, a conveying pipeline and a valve. The filling pump preferably adopts a high-power filling pump, and the conveying pipeline preferably adopts a large-diameter pipeline, so as to realize efficient short-distance conveying and pumping of the slurry. The conveying pipeline is a double-layer hollow structure, which may include an inner tube and an outer tube, and the inner tube and the outer tube are hollow areas. The microwaves generated by the microwave generator can be introduced into the hollow area of ​​the double-layer pipeline for transmission. The tube wall of the outer tube adopts anti-microwave leakage treatment to ensure that the microwaves are only transmitted inside the transmission pipeline, especially in the hollow area, so as to improve the heating efficiency of the microwaves on the inner tube and the slurry. The microwaves can heat the inner wall of the hollow large-diameter pipeline and the slurry transported by it, and accelerate the hydration reaction. Under the double-layer hollow structure of the transmission pipeline, the inner tube transmits the slurry, and the hollow area transmits the microwaves and heats the inner tube and the slurry, thereby accelerating the hydration reaction of the slurry during the transportation process. The slurry conveying link of the fast pumping subsystem has short distance and small resistance, and relies on the cooperation of high-power filling pump and large-diameter pipeline, which shortens the slurry delivery time to 10%-30% of the original time and the hydration reaction time by 40-60%.

[0076] The curing system designed in the present invention advances the hydration reaction time to the curing system, and accelerates the hydration reaction process, improves the filling efficiency, overcomes the risk of pipe blockage, and realizes continuous filling through thickening, application of admixtures, pipeline microwave heating, high-power and high-flow pumping, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0078] Figure 1 It is an application schematic diagram of the filling mining slurry rapid solidification system of the present application.

[0079] Figure 2 It is the existing paste filling process flow chart.

[0080] Figure 3 It is a schematic diagram of the comprehensive mechanized paste filling coal mining process.

[0081] Figure 4It is a schematic plan view of the working face after filling with comprehensive mechanized paste filling coal mining technology. DETAILED DESCRIPTION

[0082] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0083] like Figure 1-4 As shown, in order to facilitate the understanding of the above technical solutions of the present disclosure, the above technical solutions of the present disclosure are described in detail below through specific usage methods.

[0084] The first object of the present disclosure is to provide a rapid solidification system for backfill mining slurry, comprising a slurry receiving subsystem, a curing subsystem and a rapid pumping subsystem connected in sequence;

[0085] The slurry receiving subsystem includes a slurry receiving bin and a slurry stirring device that cooperate with each other; the slurry receiving bin receives low-concentration filling slurry transmitted from the ground, and the slurry stirring device continuously stirs the slurry in the slurry receiving bin to prevent segregation; the slurry receiving bin and the slurry stirring device cooperate with each other to achieve buffering and temporary storage, avoid interruption of the ground surface slurry preparation process and cause pipe blockage accidents, and achieve continuous preparation and transmission of slurry;

[0086] The curing subsystem includes a curing bin, which is equipped with a thickening device, an admixture adding device and a stirring device; the curing subsystem is used to increase the concentration of the slurry, accelerate the hydration reaction and curing process of the slurry, shorten the initial setting time of the slurry, and play a role in separating and buffering the slurry ground preparation and filling operations; the admixture adding device adds admixtures to the curing bin to improve the fluidity of the slurry; the thickening device removes excess water from the slurry, increases the concentration of the slurry, and shortens the curing time of the slurry;

[0087] The rapid pumping subsystem includes a filling pump, a microwave generator, and a transmission pipeline. The filling pump and the large-diameter pipeline together transport and pump the slurry over a short distance. The microwave generator generates microwaves and introduces them into the transmission pipeline. The microwaves heat the transported slurry and accelerate the hydration reaction.

[0088] In one embodiment, the input end of the slurry receiving bin is connected to the filling material mixing station on the ground, the input end of the curing bin is connected to the output end of the slurry receiving bin, the output end of the curing bin is connected to the input end of the filling pump, the output end of the filling pump is connected to the input end of the transmission pipeline, the transmission pipeline leads to the filling working surface, and a valve is provided on the transmission pipeline. The filling material mixing station is set on the ground.

[0089] In one embodiment, the admixture includes a flocculant.

[0090] In one embodiment, the thickening device removes excess moisture, which is determined based on actual needs and is preferably set at 10% to 20% of the total moisture in the curing bin.

[0091] In one embodiment, the thickening device preferably adopts a thickener. The thickener is a solid-liquid separation device based on gravity sedimentation, and its appearance is a cylindrical shallow trough with a conical bottom. With the help of a rake installed in the thickener and running slowly (1 / 2 to 1 / 6 r / min), the paste-containing slurry can be input into the thickener from the upper port, concentrated into a high-concentration slurry through gravity sedimentation, and the thickened underflow slurry is discharged from the underflow port at the bottom of the thickener.

[0092] In one embodiment, the filling pump is preferably a high-power filling pump, and the conveying pipeline is preferably a large-diameter pipeline.

[0093] In one embodiment, the transmission pipe is preferably a double-layer hollow structure.

[0094] In one embodiment, the double-layer hollow structure of the transmission pipeline includes an inner tube and an outer tube, and a hollow area is between the inner tube and the outer tube; the inner tube is used to transmit the slurry; microwaves are introduced into the hollow area to heat the tube wall of the inner tube and the slurry.

[0095] In a certain embodiment, the tube wall of the outer tube is treated with anti-microwave leakage treatment to avoid microwave leakage and ensure that microwaves are only transmitted inside the transmission pipeline, thereby improving the heating efficiency of the inner tube and slurry by microwaves.

[0096] The second object of the present disclosure is to provide a parameter confirmation method for a filling mining slurry rapid solidification system, which comprises the following steps:

[0097] S1 determines the curing bin capacity: the curing bin capacity Q c The following formula is used for calculation:

[0098]

[0099] In formula 1: k1——unbalanced mining and charging coefficient;

[0100] k2——filling expansion coefficient;

[0101] p c ——Bulk density of slurry, in t / m 3 ;

[0102] p m ——Bulk density of mined raw coal, in t / m 3 ;

[0103] Q m ——The amount of raw coal mined at the maximum filling step, in tons;

[0104] (Supplementary explanation: In the process of determining the capacity of the curing bin, the filling and mining working face adopts the cycle of "coal mining-filling-coal mining-filling". The working face is filled once after every few cuts of coal (i.e., the filling step). After it is full, the next coal mining cycle is carried out after the filling body solidifies. In order to form a closed filling space in the goaf, the method of hanging bags behind the support is adopted to fill the bags with slurry. The filling slurry is pumped out from the curing bin. Therefore, the capacity of the curing bin should not be less than one filling step, and a certain mining and filling imbalance coefficient K1 should be considered).

[0105] S2 Thickening device dehydration: When the slurry enters the curing subsystem, the thickening device is automatically controlled according to the initial state of the slurry and the dehydration amount during the dehydration and thickening process, and the excess water W that needs to be removed by thickening is calculated using the following formula 2:

[0106]

[0107] In formula 2: C1 – the initial concentration of the slurry is first tested when it enters the curing subsystem;

[0108] C2 - target concentration of slurry after dehydration using thickener;

[0109] V——-The amount of slurry that needs to be thickened to remove excess water;

[0110] W - the amount of excess water that needs to be stripped off;

[0111] S3 Determine the amount of admixture added: In the curing bin, add admixtures through the admixture adding device, and continuously stir the slurry through the stirring device. Use a viscometer to test the viscosity of the slurry every 10 minutes; when the slurry viscosity μ satisfies the following formula 3, stop adding:

[0112] μ≥4.4×10 -4 vρ c r(Formula 3);

[0113] In formula 3: μ——slurry viscosity;

[0114] V——slurry pumping velocity, m / s;

[0115] P c—— Indicates the bulk density of slurry, t / m 3 ;

[0116] r - outer diameter of the transmission pipeline;

[0117] S4 stirring and standing: the slurry is thickened and dehydrated by the thickening device to increase the concentration, then the admixture is added for full stirring, and then the slurry is stood for hydration reaction, and the standing time is less than or equal to 2h, h——hours;

[0118] During the static period, the slurry was sampled every 10 minutes, and the rheological properties of the slurry were tested using an automatic rheometer. When the maximum shear stress of the slurry reached 3000Pa, the pumping conditions were met.

[0119] S5 Determine the filling pump power: The filling pump power is calculated by the following formula 4;

[0120]

[0121] In the formula: P1——indicates the filling pump power, in W;

[0122] P c ——Indicates the bulk density of the slurry, in t / m 3 ;

[0123] g——indicates the acceleration due to gravity;

[0124] Q——indicates flow rate, in m 3 / s;

[0125] l——indicates the conveying distance, in meters;

[0126] η——indicates the efficiency of the filling pump;

[0127] S6 confirms the microwave generator power: the microwave generator power P2 is calculated using the following formula 5;

[0128]

[0129] In formula 5:

[0130] P2- represents the microwave generator power, unit is W;

[0131] Q——indicates flow rate, in m 3 / s;

[0132] P c ——-Indicates the bulk density of slurry;

[0133] λ——indicates microwave frequency;

[0134] R——Inner diameter of the outer tube wall;

[0135] r ——is the outer diameter of the inner tube wall;

[0136] ε——The dielectric constant between the outer tube and the inner tube.

[0137] Working principle: At present, the filling station is built on the ground, and the pipeline is directly input into the filling working face. There are many uncontrollable factors in the middle, such as pipe blockage, filling operation is suspended due to external factors, and the line is long, the resistance is large, the slurry concentration cannot be too high, etc. The hydration reaction is carried out after filling, resulting in a long curing time for the filling slurry. This patent pioneered the construction of a maintenance center close to the filling operation point underground. After the low-concentration slurry enters the maintenance center, it is concentrated, added with additives such as flocculants, and then left to stand for preliminary hydration reaction. It is already a high-concentration slurry when pumped. Due to the short distance, the pumping process can be pumped with a large flow rate. The pipeline adopts a hollow double-layer pipeline. The inner pipeline transports the slurry, and the hollow part of the pipeline transports microwaves. The outer layer of the pipe wall is made of special materials, which can shield microwave leakage and reflect microwaves to the inner wall of the pipe. The slurry is heated and catalyzed, and the hydration reaction is further accelerated in the pipeline. When the slurry enters the filling operation site, the main hydration reaction has been completed by 70-90%, and it can be initially solidified after a short time, saving time.

[0138] When implementing the present disclosure, the following case can be referred to: a filling working face, inclined length 80m, mined coal seam thickness 2m, raw coal bulk density 1.4t / m 3 , normal filling step distance is 2m, and maximum filling step distance is 3m.

[0139] A filling material mixing station is built in the ground industrial square, and a filling slurry receiving subsystem, a maintenance subsystem and a fast pumping subsystem are built at the underground working face. The designed receiving bin has a capacity of 200m 3 According to the calculation of this patent, the curing chamber volume is 600m 3 The slurry curing subsystem is located at the entrance of the working face, about 6000m away from the ground mixing station and about 500m away from the filling operation point.

[0140] (A) In the filling material mixing station on the ground, the coal gangue is first crushed into graded particles below 5mm, mixed with cement in a certain proportion, and transported to the slurry receiving bin underground through a φ200mm diameter pipeline at a concentration of 60%.

[0141] (B) The filling slurry is transported from the slurry receiving bin to the curing bin for dehydration and concentration treatment, and the concentration is increased to 80%. Then, 1% of early strength agent and water reducing agent (admixture) are added respectively to improve the fluidity, strength and viscosity of the slurry.

[0142] (C) After sufficient stirring, the mixture was allowed to stand for 38 minutes to allow for a preliminary hydration reaction;

[0143] (D) When the slurry hydration reaction has proceeded to a certain extent and the slurry viscosity is not less than 2300Pa / s, a 400kW high-power filling pump and a large-diameter delivery pipeline with a diameter of 350mm are used. The delivery pipeline is a double-layer hollow structure and is transported to the filling operation point on the working face;

[0144] (E) starting a microwave generator to generate microwaves, and introducing the microwaves into the hollow area of ​​the double-layer pipe for transmission. The microwaves are reflected by the outer wall of the pipe and absorbed by the inner wall of the pipe to generate heat;

[0145] (F) The 500m long large-diameter pipeline from the curing bin to the filling operation point uses microwave heating to further accelerate the hydration reaction process of the slurry;

[0146] (G) After the slurry is pumped to the filling position of the goaf, according to actual measurements, it reaches initial setting after being left to stand for about 4 hours, and the strength reaches 0.5MPa;

[0147] (H) The present invention uses a pre-hydration reaction, which takes only 1 / 3 of the usual 12-24 hours.

[0148] (I) The working face saves about 10 hours of waiting time, which can be used for coal production, greatly improving production efficiency by 90%.

[0149] In summary, the unique design of the present invention achieves the following beneficial effects: (A) Most of the hydration reactions are completed in the curing tank, which saves the need for hydration reactions after filling and greatly shortens the solidification time; (B) Pipe blockage will not occur, and the slurry can be pumped into the well at a lower concentration, and then undergo secondary thickening treatment in the curing tank, avoiding pipe blockage in high-concentration slurry well sites; (C) The curing bin is located underground and is close to the filling point, so a large-diameter, high-flow pumping method can be used, and the filling efficiency is high; (D) The ground surface slurry can be pumped into the underground curing tank continuously without flushing the pipeline; (E) The slurry transportation time and the solidification time after filling are greatly shortened, the operation process and pipe blockage are simplified, and the efficiency of coal mining operations at the filling working face is improved; (F) Microwave instant heating is used to accelerate the hydration reaction and shorten the initial setting time.

[0150] The above are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A rapid solidification system for filling mining slurry, characterized in that: It includes a slurry receiving subsystem, a curing subsystem and a rapid pumping subsystem connected in sequence; The slurry receiving subsystem includes a slurry receiving bin and a slurry stirring device that cooperate with each other; the slurry receiving bin receives low-concentration filling slurry transmitted from the ground, and the slurry stirring device continuously stirs the slurry in the slurry receiving bin to prevent segregation; the slurry receiving bin and the slurry stirring device cooperate with each other to achieve buffering and temporary storage, avoid interruption of the ground surface slurry preparation process and cause pipe blockage accidents, and achieve continuous preparation and transmission of slurry; The curing subsystem includes a curing bin, in which a thickening device, an admixture adding device and a stirring device are provided; the curing subsystem is used to increase the concentration of the slurry, accelerate the hydration reaction and curing process of the slurry, shorten the initial setting time of the slurry, and play a role in separating and buffering the slurry ground preparation and filling operations; the admixture adding device adds admixtures to the curing bin to improve the fluidity of the slurry; the thickening device removes excess water in the slurry, increases the concentration of the slurry, and shortens the curing time of the slurry; The rapid pumping subsystem includes a filling pump, a microwave generator, and a transmission pipeline; the filling pump and the large-diameter pipeline together transport and pump the slurry over a short distance; the microwave generator generates microwaves and introduces them into the transmission pipeline, and the microwaves heat the transported slurry and accelerate the hydration reaction.

2. The backfill mining slurry rapid solidification system according to claim 1 is characterized in that: The input end of the slurry receiving bin is connected to the filling material mixing station on the ground, the input end of the curing bin is connected to the output end of the slurry receiving bin, the output end of the curing bin is connected to the input end of the filling pump, the output end of the filling pump is connected to the input end of the conveying pipeline, the conveying pipeline leads to the filling working surface, and a valve is provided on the conveying pipeline.

3. The backfill mining slurry rapid solidification system according to claim 1 is characterized in that: The admixture includes a flocculant.

4. The backfill mining slurry rapid solidification system according to claim 1 is characterized in that: The thickening device removes the excess moisture, accounting for 10%-20% of the total moisture in the curing bin.

5. The backfill mining slurry rapid solidification system according to claim 4 is characterized in that: The thickening device adopts a thickener.

6. The backfill mining slurry rapid solidification system according to claim 1, characterized in that: The filling pump adopts a high-power filling pump, and the transmission pipeline adopts a large-diameter pipeline.

7. The backfill mining slurry rapid solidification system according to claim 6, characterized in that: The transmission pipeline is a double-layer hollow structure.

8. The backfill mining slurry rapid solidification system according to claim 7, characterized in that: The conveying pipeline includes an inner tube and an outer tube, and a hollow area is formed between the inner tube and the outer tube; the inner tube is used to convey the slurry; the microwave is introduced into the hollow area, thereby heating the tube wall of the inner tube and the slurry.

9. The backfill mining slurry rapid solidification system according to claim 8, characterized in that: The tube wall of the outer tube is treated with anti-microwave leakage treatment to avoid microwave leakage and ensure that microwaves are only transmitted inside the transmission pipeline, thereby improving the heating efficiency of the inner tube and slurry by microwaves.

10. The parameter confirmation method of the backfill mining slurry rapid solidification system according to claims 7-9, characterized in that: The following steps are involved: S1 determines the curing bin capacity: the curing bin capacity Q c The following formula is used for calculation: In formula 1: k1——unbalanced coefficient of mining and charging; k2——filling expansion coefficient; p c ——Bulk density of slurry, in t / m 3 ; p m ——Bulk density of mined raw coal, in t / m 3 ; Q m ——The amount of raw coal mined at the maximum filling step, in tons; S2 Thickening device dehydration: When the slurry enters the curing subsystem, the thickening device is automatically controlled according to the initial state of the slurry and the dehydration amount during the dehydration and thickening process, and the excess water W that needs to be removed by thickening is calculated using the following formula 2: In Formula 2: C1 is the initial concentration of the slurry first tested when the slurry enters the curing subsystem; C2 is the target concentration of the slurry after dehydration using the thickening device; V——-The amount of slurry that needs to be thickened to remove the excess water; W——the amount of excess water that needs to be removed; S3 determines the amount of admixture added: in the curing bin, the admixture is added through the admixture adding device, and the slurry is continuously stirred through the stirring device, and the viscosity of the slurry is tested every 10 minutes using a viscometer; when the slurry viscosity μ satisfies the following formula 3, the addition is stopped: μ≥4.4×10 -4 vρ c r(Formula 3); In formula 3: μ——slurry viscosity; V——slurry pumping velocity, m / s; P c—— Indicates the bulk density of slurry, t / m 3 ; r - the outer diameter of the conveying pipeline; S4 stirring and standing: the slurry is thickened and dehydrated by the thickening device to increase the concentration, then the admixture is added to stir fully, and then standing for hydration reaction, the standing time is <= 2h, h——hours; During the static period, the slurry was sampled every 10 minutes, and the rheological properties of the slurry were tested using an automatic rheometer. When the maximum shear stress of the slurry reached 3000Pa, the pumping conditions were met. S5 determines the filling pump power: the filling pump power is calculated by the following formula 4; In the formula: P1——indicates the power of the filling pump, in W; P c ——Indicates the bulk density of the slurry, in t / m 3 ; g——indicates the acceleration due to gravity; Q——indicates flow rate, in m 3 / s; l——indicates the conveying distance, in meters; η——indicates the efficiency of the filling pump; S6 confirms the microwave generator power: the microwave generator power P2 is calculated using the following formula 5; In formula 5: P2- represents the microwave generator power, unit is W; Q——indicates flow rate, unit is m 3 / s; P c ——-Indicates the bulk density of slurry; λ——indicates microwave frequency; R——is the inner diameter of the outer tube wall; r ——is the outer diameter of the inner tube wall; ε——is the dielectric constant between the outer tube and the inner tube.

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