Underground coal gangue utilization method in underground mine

Abstract

The present application relates to the technical field of coal processing, in particular to a method for utilizing underground coal gangue in underground coal mine, step one: collecting underground coal gangue, transporting to a to-be-hardened floor roadway for storage; step two: using a crusher to crush the underground coal gangue; step three: adding the crushed underground coal gangue, cement, solidification additive and water into a mixer for mixing and stirring to obtain a mixture; step four: transporting the mixture obtained in step three to the to-be-hardened floor roadway, paving and forming, and obtaining a hardened floor roadway after curing. The present application directly applies the underground coal gangue in underground coal mine to the roadway floor hardening, and the utilization rate of the underground coal gangue is high, and the additive is environmentally friendly and easy to degrade.

Description

Technical Field

[0001] This invention relates to the field of coal processing technology, specifically to a method for utilizing coal gangue in underground coal mines. Background Technology

[0002] Coal mines are areas where humans extract coal resources from coal-rich areas, generally divided into underground coal mines and open-pit coal mines. The vast majority of coal mines in my country are underground mines. Because the coal seams in underground mines are far from the surface, it is generally necessary to excavate tunnels underground to mine the coal. Underground mining and tunneling in underground coal mines generate a large amount of coal gangue.

[0003] Coal gangue is a type of rock that occurs alongside coal seams during coal formation. It is primarily composed of siltstone and fine sandstone, and is found in blocky shapes of varying sizes. It has poor flowability and a hardness coefficient ranging from f=4 to 8. Currently, there are two main methods for handling underground coal gangue: one is backfilling at the underground mining face. This method can save on transportation costs to some extent, but due to the large volume of coal gangue and the complexity of the backfilling process, backfilling mining leads to increased production costs. The other method involves loading underground coal gangue onto trucks and transporting it to the surface, where it is centrally stockpiled near the mine entrance or used for comprehensive utilization. Since underground coal mines are far from the surface, the transportation process is lengthy, undoubtedly increasing transportation costs. Furthermore, stockpiling coal gangue near the mine entrance causes significant damage to the ecological environment.

[0004] Patent application number 202010366358.1 discloses a coal slime-based roadway paving material and its preparation method. The method involves mixing coal slime, gangue, cement, water-reducing agent, early-strength agent, fiber, and water to prepare the roadway paving material. Although this method can achieve the reuse of gangue to a certain extent, the specific gravity of cement is significantly greater than that of gangue, resulting in low gangue utilization. Furthermore, in order to reduce the curing time of the roadway floor paving material and improve its early strength, the patent uses naphthalene-based water-reducing agents, polyethylene fibers, and other difficult-to-degrade polymeric compound additives, which have adverse effects on the ecological environment. Summary of the Invention

[0005] To address the technical problems of low utilization rate of underground coal gangue and difficult degradation of additives in existing technologies, this invention provides a method for utilizing underground coal gangue in underground coal mines. This method directly applies underground coal gangue to the hardening of the roadway floor, resulting in high utilization rate of underground coal gangue and environmentally friendly and easily degradable additives.

[0006] In a first aspect, the present invention provides a method for utilizing coal gangue in underground coal mines, comprising the following steps:

[0007] Step 1: Collect coal gangue from underground mines and transfer the collected coal gangue to a transport device for storage in a roadway with a hardened floor for later use.

[0008] Step 2: When the underground coal gangue stored in the roadway to be hardened reaches the preset volume, the underground coal gangue is crushed using a crusher. After crushing, the particle size of the underground coal gangue is 0.5-20mm. The crusher includes a mixing blade for mixing highly viscous materials.

[0009] Step 3: Add the crushed underground coal gangue, cement, curing additive, and water to a mixer and mix to obtain a mixture. The mass fraction of the crushed underground coal gangue is 1945-1955, the mass fraction of cement is 275-285, the mass fraction of curing additive is 4-6, and the mass fraction of water is 193-203. The mass fractions of cement and curing additive can be adjusted according to the required compressive strength. All components of the curing additive are easily degradable.

[0010] Step 4: Transport the mixture obtained in Step 3 to the roadway to be hardened, spread it into shape, and cure it to obtain the hardened roadway.

[0011] Furthermore, the underground coal gangue in step one includes coal gangue generated during the tunneling face process. The coal gangue generated during the tunneling face process has a large discharge volume, relatively low coal content, limited reusability, and a large centralized stockpiling volume. The technical solution disclosed in this invention is mainly used to treat this type of coal gangue, effectively mitigating the adverse environmental and soil impacts of such coal gangue stockpiling and improving the utilization rate of coal gangue generated during the tunneling face process.

[0012] Furthermore, the methods for collecting underground coal gangue in step one include using a loader to load or using a roadheader to cut.

[0013] Furthermore, the transport device in step one includes mine cars or belt conveyors.

[0014] Furthermore, the preset volume in step two is 20-25m³. 3 .

[0015] Furthermore, the mixing blade in step two includes a mixing shaft with two mixing discs. Each mixing disc is equipped with two sets of irregularly shaped mixing blades and two sets of mixing blades. The irregularly shaped mixing blades consist of two identical L-shaped blades arranged symmetrically and facing opposite directions. The mixing blades consist of a mounting plate and right-angled trapezoidal mixing blades, which are fixed to the mixing discs by the mounting plate. Because underground coal gangue has a certain degree of cohesiveness or contains clay components, mixing is difficult and uneven mixing is prone to occur. This invention uses a mixing blade to achieve thorough mixing and multiple shearing through the combined action of the irregularly shaped mixing blades and mixing blades, improving mixing efficiency and promoting uniform mixing of underground coal gangue with cement, solidifying additives, water, and other components. This helps solve the problem of low utilization rate of underground coal gangue caused by the difficulty of mixing.

[0016] Furthermore, the solidification additive includes a culture medium, potassium sulfate, citric acid, magnesium chloride, sodium chloride, and calcium chloride. The culture medium comprises cobalt chloride, tartaric acid, ammonium chloride, potassium carbonate, and borax. This culture medium is beneficial for enhancing the activity of microorganisms in the soil. Active microorganisms can consume excess calcium hydroxide in the mixture, promoting the growth of calcium chloride. 2+ With OH - The balance of these components ensures that the cured mixture exhibits high mechanical strength and durability. Firstly, the curing additive used in this invention comprises water-soluble salts or small-molecule organic acids, eliminating the problem of difficult-to-degrade components. Secondly, the combined use of the curing additive and a mixer effectively solidifies crushed clay gangue. Thirdly, the curing additive includes various electrolytes, which balance the surface charge of underground coal gangue particles, reduce the thickness of the double electric layer, and enhance the chemical and physical reactions of the mixture, resulting in a stable composite structure and improved water stability and strength of the surface layer. Fourthly, the sodium chloride and citric acid in the curing additive activate and catalyze active substances in the underground coal gangue and cement. Fifthly, the acids and salts in the curing additive undergo ion exchange in the presence of water, forming surface-active substances that not only improve the stability and fluidity of the mixture dispersion system but also reduce water content and regulate setting time.

[0017] Furthermore, in step three, the mixing speed is 100-200 rpm, and the mixing time is 3-5 minutes per cycle. The mixing can be performed once or more.

[0018] Furthermore, the paving thickness in step four is 100-300mm. The paving thickness can be determined according to the needs of the roadway where the base slab is to be hardened.

[0019] Furthermore, step four includes watering. Watering not only prevents the mixture from drying out during the hardening process, but also provides moisture to the nutrient solution in the mixture, thereby increasing the activity of microorganisms in the soil.

[0020] The beneficial effects of this invention are as follows:

[0021] This invention provides a method for utilizing underground coal gangue in coal mines. After collection, the underground coal gangue is directly transported to the roadway where the floor needs to be hardened, reducing the transportation and hoisting steps and saving transportation costs. Storing the underground coal gangue in the roadway where the floor needs to be hardened avoids the increased costs and soil pollution caused by occupying additional storage space.

[0022] This invention uses a crusher with a stirring blade for mixing highly viscous materials to crush underground coal gangue. After crushing, the underground coal gangue has a particle size of 0.5-20mm, which is small and has a certain degree of uniformity, which is beneficial to increasing the plasticity of the underground coal gangue.

[0023] This invention involves adding crushed underground coal gangue, cement, curing additives, and water to a mixer in a single step for mixing. The resulting mixture is uniform, stable, and easy to operate. The mass fraction of the crushed underground coal gangue used for mixing is 1945-1955, the mass fraction of cement is 275-285, the mass fraction of curing additive is 4-6, and the mass fraction of water is 193-203. The underground coal gangue accounts for the highest mass fraction, resulting in high utilization.

[0024] The method for utilizing underground coal gangue disclosed in this invention achieves "on-site material sourcing," with a simple process, convenient operation, strong adaptability, low transportation costs, and excellent environmental benefits. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the construction process of Embodiment 1 of the present invention.

[0027] Figure 2 This is a particle diagram of underground coal gangue before crushing in Embodiment 1 of the present invention.

[0028] Figure 3 This is a particle diagram of underground coal gangue after crushing in Embodiment 1 of the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0030] Examples 1-3 use underground coal gangue utilization methods in underground coal mines to process 1303N and 13 上 The floor slab of the 03S upper level tunnel was hardened. The Changcheng No. 6 Mine adopted trackless rubber-tired vehicles to improve auxiliary transportation capacity. The curing additive used in Examples 1-3 was a patented environmentally friendly XC-type coagulant purchased from Qingdao Endian Road Environmental Protection Technology Co., Ltd.

[0031] Example 1

[0032] A method for utilizing coal gangue in underground coal mines includes the following steps:

[0033] Step 1: Use a loading machine to load the underground coal and gangue generated during the tunneling face into 1-ton mine cars. Transport to 1303N, 13 上 03S Shangping Lane is stored for later use.

[0034] Step 2: Before hardening construction, apply 1303N and 13 上 After the 03S upper level tunnel reaches the design value and all loose debris is cleared, formwork should be erected and securely fixed in the construction area. Within the hardened area, safety ropes should be strung to prevent others from stepping on it. When 1303N, 13 上 The underground coal gangue stored in the 03S upper level tunnel reaches 20m³. 3 At that time, a crusher was used to crush the underground coal gangue. After crushing, the particle size of the underground coal gangue was 0.5-20mm. The crusher included a mixing blade for mixing highly viscous materials. The mixing blade included a mixing shaft with two mixing discs. Each mixing disc was equipped with two sets of irregularly shaped mixing blades and two sets of mixing blades. The irregularly shaped mixing blades consisted of two identical L-shaped blades arranged symmetrically and facing opposite directions. The mixing blades consisted of a mounting plate and right-angled trapezoidal mixing blades, which were fixed to the mixing discs by the mounting plate.

[0035] Step 3: Add the crushed underground coal gangue, cement, solidifying additive, and water to a mixer and mix. The mixing speed is 150 r / min, the mixing time is 5 min, and the mixing is repeated once to obtain a mixture. The mass of the crushed underground coal gangue is 1950 kg, the mass of cement is 280 kg, the mass of solidifying additive is 4.9 kg, and the mass of water is 198 kg. The solidifying additive includes a culture medium, potassium sulfate, citric acid, magnesium chloride, sodium chloride, and calcium chloride. The components of the culture medium include cobalt chloride, tartaric acid, ammonium chloride, potassium carbonate, and borax.

[0036] Step 4: Transport the mixture obtained in Step 3 to 1303N and 13 using a forklift. 上 03S upper level roadway, paved and formed, with a paving thickness of 100mm. The paving thickness can be determined according to the needs of the roadway floor to be hardened. The concrete must be thoroughly mixed during paving, and a vibrator should be used to compact it during pouring to prevent honeycomb and pitting, ensuring a level surface. After the floor slab hardens, the hardened area should be pre-wetted with water daily for 7 consecutive days.

[0037] The compressive strength of the hardened ground reaches 20 MPa after 7 days of solidification and 30 MPa after 28 days.

[0038] Example 2

[0039] A method for utilizing coal gangue in underground coal mines includes the following steps:

[0040] Step 1: Use a roadheader to cut the underground coal gangue generated during the tunneling face, and transfer the underground coal gangue to a belt conveyor for transportation to 1303N and 13... 上 03S upper level tunnel storage for later use, belt conveyor is belt secondary transport.

[0041] Step 2: Before hardening construction, apply 1303N and 13 上 After the 03S upper level tunnel reaches the design value and all loose debris is cleared, formwork should be erected and securely fixed in the construction area. Within the hardened area, safety ropes should be strung to prevent others from stepping on it. When 1303N, 13 上 The underground coal gangue stored in the 03S upper level tunnel reaches 23m³. 3At that time, a crusher was used to crush the underground coal gangue. After crushing, the particle size of the underground coal gangue was 0.5-20mm. The crusher included a mixing blade for mixing highly viscous materials. The mixing blade included a mixing shaft with two mixing discs. Each mixing disc was equipped with two sets of irregularly shaped mixing blades and two sets of mixing blades. The irregularly shaped mixing blades consisted of two identical L-shaped blades arranged symmetrically and facing opposite directions. The mixing blades consisted of a mounting plate and right-angled trapezoidal mixing blades, which were fixed to the mixing discs by the mounting plate.

[0042] Step 3: Add the crushed underground coal gangue, cement, solidifying additive, and water to a mixer and mix. The mixing speed is 200 rpm, the mixing time is 3 minutes, and the mixing is repeated once to obtain a mixture. The mass of the crushed underground coal gangue is 1952 kg, the mass of cement is 278 kg, the mass of solidifying additive is 4.5 kg, and the mass of water is 200 kg. The solidifying additive includes a culture medium, potassium sulfate, citric acid, magnesium chloride, sodium chloride, and calcium chloride. The components of the culture medium include cobalt chloride, tartaric acid, ammonium chloride, potassium carbonate, and borax.

[0043] Step 4: Transport the mixture obtained in Step 3 to 1303N and 13 using a forklift. 上 03S upper leveling tunnel is paved with a thickness of 300mm. The paving thickness can be determined according to the needs of the tunnel floor to be hardened. The concrete must be thoroughly mixed during paving and vibrated with a vibrator during pouring to prevent honeycomb and pitting, ensuring a level surface. After the floor hardens, the hardened area is pre-wetted with water daily for 7 consecutive days.

[0044] The compressive strength of the hardened ground reaches 22 MPa after 7 days of solidification and 31 MPa after 28 days.

[0045] Example 3

[0046] A method for utilizing coal gangue in underground coal mines includes the following steps:

[0047] Step 1: Use a roadheader to cut the underground coal gangue generated during the tunneling face, and transfer the underground coal gangue to a belt conveyor for transportation to 1303N and 13... 上 03S upper level tunnel storage for later use, belt conveyor is belt secondary transport.

[0048] Step 2: Before hardening construction, apply 1303N and 13 上 After the 03S upper level tunnel reaches the design value and all loose debris is cleared, formwork should be erected and securely fixed in the construction area. Within the hardened area, safety ropes should be strung to prevent others from stepping on it. When 1303N, 13 上The underground coal gangue stored in the 03S upper level tunnel reaches 25m³. 3 At that time, a crusher was used to crush the underground coal gangue. After crushing, the particle size of the underground coal gangue was 0.5-20mm. The crusher included a mixing blade for mixing highly viscous materials. The mixing blade included a mixing shaft with two mixing discs. Each mixing disc was equipped with two sets of irregularly shaped mixing blades and two sets of mixing blades. The irregularly shaped mixing blades consisted of two identical L-shaped blades arranged symmetrically and facing opposite directions. The mixing blades consisted of a mounting plate and right-angled trapezoidal mixing blades, which were fixed to the mixing discs by the mounting plate.

[0049] Step 3: Add the crushed underground coal gangue, cement, solidifying additive, and water to a mixer and mix. The mixing speed is 100 r / min, the mixing time is 4 min, and the mixing is repeated once to obtain a mixture. The mass of the crushed underground coal gangue is 1948 kg, the mass of cement is 283 kg, the mass of solidifying additive is 5.1 kg, and the mass of water is 195 kg. The solidifying additive includes a culture medium, potassium sulfate, citric acid, magnesium chloride, sodium chloride, and calcium chloride. The components of the culture medium include cobalt chloride, tartaric acid, ammonium chloride, potassium carbonate, and borax.

[0050] Step 4: Transport the mixture obtained in Step 3 to 1303N and 13 using a forklift. 上 03S upper level roadway, paved and formed, with a paving thickness of 180mm. The paving thickness can be determined according to the needs of the roadway floor to be hardened. The concrete must be thoroughly mixed during paving, and a vibrator should be used to compact it during pouring to prevent honeycomb and pitting, ensuring a level surface. After the floor slab hardens, the hardened area should be pre-wetted with water daily for 7 consecutive days.

[0051] The compressive strength of the hardened ground reaches 23 MPa after 7 days of solidification and 33 MPa after 28 days.

[0052] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A method for utilizing coal gangue in underground coal mines, characterized in that, Includes the following steps: Step 1: Collect coal gangue from underground mines and transfer the collected coal gangue to a transport device for storage in a roadway with a hardened floor for later use. Step 2: When the underground coal gangue stored in the roadway to be hardened reaches the preset volume, a crusher is used to crush the underground coal gangue. After crushing, the particle size of the underground coal gangue is 0.5-20mm. The crusher includes a mixing blade for mixing highly viscous materials. The mixing blade includes a mixing shaft with two mixing discs. Each mixing disc is equipped with two sets of irregularly shaped mixing blades and two sets of mixing blades. The irregularly shaped mixing blades include two L-shaped blades of the same specification arranged symmetrically and facing opposite directions. The mixing blades include a mounting plate and right-angled trapezoidal mixing blades, which are fixed to the mixing discs by the mounting plate. Step 3: Add the crushed underground coal gangue, cement, solidifying additive, and water to a mixer and mix to obtain a mixture. The mass fraction of the crushed underground coal gangue is 1945-1955, the mass fraction of cement is 275-285, the mass fraction of solidifying additive is 4-6, and the mass fraction of water is 193-203. The solidifying additive includes a culture medium, potassium sulfate, citric acid, magnesium chloride, sodium chloride, and calcium chloride. The components of the culture medium include cobalt chloride, tartaric acid, ammonium chloride, potassium carbonate, and borax. All components of the solidifying additive are easily degradable. Step 4: Transport the mixture obtained in Step 3 to the roadway to be hardened, spread it into shape, and cure it to obtain the hardened roadway.

2. The method for utilizing underground coal gangue in a coal mine as described in claim 1, characterized in that, The underground coal gangue in Step 1 includes the coal gangue generated during the tunneling face process.

3. A method for utilizing underground coal gangue in a coal mine as described in claim 1, characterized in that, The methods for collecting underground coal gangue in step one include using a loader to load or using a roadheader to cut.

4. A method for utilizing underground coal gangue in a coal mine as described in claim 1, characterized in that, The transport equipment in step one includes mine cars or belt conveyors.

5. A method for utilizing underground coal gangue in a coal mine as described in claim 1, characterized in that, The preset volume in step two is 20-25m³. 3 .

6. A method for utilizing underground coal gangue in a coal mine as described in claim 1, characterized in that, The mixing speed in step three is 100-200 r / min, and the mixing time is 3-5 min / time.

7. A method for utilizing underground coal gangue in a coal mine as described in claim 1, characterized in that, The paving thickness in step four is 100-300mm.

8. A method for utilizing underground coal gangue in a coal mine as described in claim 1, characterized in that, The maintenance methods in step four include watering.

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