A comprehensive treatment method for coal mine well water

Abstract

The present invention relates to a comprehensive treatment method for coal mine well water, comprising: S1. Introducing the coal mine well water into an inclined plate sedimentation tank for treatment. The first water-containing coal slime is discharged from below the inclined plate sedimentation tank. A scum removal mechanism is provided above the inclined plate sedimentation tank to remove insoluble solids or oil floating on the surface of the coal mine well water. The inclined plate sedimentation tank outputs the first treated water; S2. Adding a coagulant to the first treated water and treating it with a microsand enhanced flocculation sedimentation tank to obtain the second water-containing coal slime and the second treated water; S3. Using crop straw ash or boiler coal slag to adsorb and purify the second treated water. After the drained water is filtered, the third mixed slag and the third treated water are obtained. The third treated water is used as non-drinking domestic water or construction water; S4. Combining the first water-containing coal slime and the second water-containing coal slime, ball milling and activating them underground to obtain activated coal slime, and making the activated coal slime into an underground plugging material; or making the activated coal slime and the third mixed slag into a backfill grouting material for goafs.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mines, and in particular to a comprehensive treatment method for coal mine well water. Background Art

[0002] During the coal mining process, groundwater comes into contact with coal seams and rock formations. Coupled with the influence of human activities, a series of physical, chemical, and biochemical reactions occur to form coal mine well water. Its water quality has significant characteristics of the coal industry: the suspended solids content in coal mine well water containing suspended solids is much higher than that of surface water; and the particle size of the contained suspended solids is small (large specific surface area, high activity), light in specific gravity, slow in sedimentation speed, and poor in coagulation effect; moreover, the total ion content in coal mine well water is much higher than that of general surface water. The main problems existing in coal mine well water are as follows:

[0003] (1) Due to the too high suspended solids content in mine water, serious coal slime deposition occurs in the underground central sump, seriously affecting the effective volume of the sump. As a result, the drainage energy consumption is serious, the wear and maintenance costs of the pump house and pipeline equipment are high, the sump needs to be dredged frequently, and the sump siltation affects the safe and effective volume, etc.

[0004] (2) The drainage energy consumption is large and the maintenance and repair costs are high. When coal mine wastewater enters the sump, the mixed lifting of mud and water leads to large lifting energy consumption, serious wear of drainage pumps, and frequent need for maintenance; the drainage pipeline is severely worn.

[0005] (3) The operating load of the ground coal mine water treatment station is large. The high suspended solids content in the influent leads to a large treatment load of the ground water treatment station, high operating costs, and high suspended solids content in the sedimentation effluent, affecting the stable operation of subsequent processes.

[0006] Therefore, it is necessary to propose an improved solution for the treatment of coal mine well water. Summary of the Invention

[0007] (I) Technical Problems to be Solved

[0008] In view of the above-mentioned disadvantages and deficiencies of the prior art, the present invention provides a comprehensive treatment method for coal mine well water. By performing solid-liquid separation underground, the obtained solid coal slime is directly ball-milled and activated underground for use in preparing underground plugging materials or gob backfill grouting materials, and the produced water is used for mine heating or non-drinking domestic water, so as to reduce drainage energy consumption, slow down equipment wear, reduce treatment costs, and solve the technical problem of increasing the burden on the surrounding environment of the mine area due to the relatively rough treatment method of coal mine well water.

[0009] (II) Technical Solutions

[0010] To achieve the above object, the main technical solutions adopted by the present invention include:

[0011] In the first aspect, the present invention provides a comprehensive treatment method for coal mine well water, including the following steps:

[0012] S1. Coal mine well water sedimentation and separation: The coal mine well water is introduced into an inclined plate sedimentation tank for treatment. The first water-containing coal slime is discharged from the lower part of the inclined plate sedimentation tank. A scum removal mechanism is provided above the inclined plate sedimentation tank to remove insoluble solids or oil floating on the surface of the coal mine well water through the scum removal mechanism; the inclined plate sedimentation tank outputs the first treated water.

[0013] S2. Purification of the first treated water: A coagulant is added to the first treated water, and it is treated with a microsand enhanced flocculation sedimentation tank to obtain the second water-containing coal slime and the second treated water.

[0014] S3. Purification of the second treated water: The second treated water is adsorbed and purified using crop straw ash residue or boiler coal slag. After the drained water is filtered, the third mixed slag and the third treated water are obtained; the third treated water is used as non-drinking domestic water or construction water.

[0015] S4. The first water-containing coal slime and the second water-containing coal slime are combined and ball mill activated underground to obtain activated coal slime, and the activated coal slime is used to prepare coal mine underground plugging materials; or the activated coal slime and the third mixed slag are made into goaf backfill grouting materials.

[0016] According to a preferred embodiment of the present invention, in S1, the SS of the coal mine well water is 10000 - 15000 mg / L, and the oil content is 100 - 4000 mg / L; in S3, the SS of the third treated water ≤ 50 mg / L, and the oil content ≤ 5 mg / L.

[0017] According to a preferred embodiment of the present invention, in S1, the inclined plate sedimentation tank is made of fiberglass, metal plate or high-hardness resin material; the scum removal mechanism is arranged above the inclined plate sedimentation tank, and it includes a conveyor belt and a scraper arranged on the conveyor belt. The conveyor belt includes a first section and a second section. Its first section is parallel to the liquid level of the inclined plate sedimentation tank, and the second section is located at the end of the conveyor belt and is inclined upward relative to the first section. A slope is provided on one side of the upper end of the inclined plate sedimentation tank, and this slope corresponds to and is parallel to the second section; through the rotation of the conveyor belt, the scraper is driven to move above the liquid level of the inclined plate sedimentation tank, and the insoluble solids or oil floating on the surface of the coal mine well water are discharged from the slope of the inclined plate sedimentation tank.

[0018] According to a preferred embodiment of the present invention, in S1, the inclined plate sedimentation tank includes an inclined plate group, and the inclined plates in the inclined plate group are arranged in an inclined and parallel and spaced manner; a sludge discharge port is provided at the bottom of the inclined plate sedimentation tank for discharging the first water-containing coal slime; and the water inlet of the inclined plate sedimentation tank is provided at a position below the horizontal midline of the inclined plate group; an overflow wall is provided at the upper end of the side of the inclined plate sedimentation tank opposite to the water inlet, the overflow wall is connected to an overflow tank, the overflow tank is provided with a water outlet, and the first treated water is output from the water outlet; the overflow tank is not directly communicated with the clear water above the inclined plate group.

[0019] According to a preferred embodiment of the present invention, in S2, the microsand enhanced flocculation sedimentation tank includes a tank made of fiberglass, metal plate or high-hardness resin material. An inlet is provided at the bottom of one side of the tank, and no first partition, second partition and third partition are provided in the tank; the first partition is installed at the bottom of the tank and extends upward but is not connected to the top of the tank, the second partition is installed at the top of the tank and extends downward but is not connected to the bottom of the tank, and the third partition is installed at the bottom of the tank and extends upward but is not connected to the top of the tank;

[0020] The first partition and the side wall at one end of the tank form a water inlet area; the area between the second partition and the first partition forms a sand addition area; the area between the second partition and the third partition forms a transition area, and the area between the third partition and the side wall at the other end of the tank forms an enhanced sedimentation area; a coagulant dosing port is provided in the water inlet area, and a microsand feeding port and a polymer coagulant aid dosing port are provided in the sand addition area; an inclined tube assembly is provided above the enhanced sedimentation area, the inclined tube assembly is immersed below the water surface, the clear water area is above the inclined tube assembly, and a water outlet communicating with the clear water area is provided at the upper part of the tank for discharging the second treated water;

[0021] A mud and sand circulation port is provided at the bottom of the enhanced sedimentation area, a sand leakage net is provided above the mud and sand circulation port, and a mud scraper is provided above the sand leakage net. The mud scraper generates friction by pushing the mud and sand, scrapes off the mud on the surface of the microsand, and the particle size becomes smaller and falls into the mud and sand circulation port of the sand leakage net. The scraped mud is deposited in flakes at the bottom of the enhanced sedimentation area. A sludge discharge port is provided at the bottom of the tank for discharging the second water-containing coal slime.

[0022] According to a preferred embodiment of the present invention, in S3, the crop straw ash residue is obtained by crushing crop straws (such as wheat straw, rice straw, soybean straw, corn stalks, etc.), compressing them into a mold, and burning them in an incinerator to obtain straw ash residue. The heat generated by the burning can be supplied to the heating equipment in the mining area, and the straw ash residue is used as an adsorbent to treat acid-base ions (removing corrosion) or heavy metal ions in water.

[0023] According to a preferred embodiment of the present invention, in S3, the boiler cinder is made into a cinder ash adsorption material according to the following method and is used to treat acid-base ions or heavy metal ions in water:

[0024] Take industrial boiler cinder, crush it into 100 - 150 mesh; mix the boiler cinder and cement according to a mass ratio of 5 - 10:1, granulate, and calcine to obtain a boiler cinder adsorption material.

[0025] According to a preferred embodiment of the present invention, in S3, the non - potable domestic water includes heating water, irrigation water, etc.; the construction water includes concrete construction water.

[0026] According to a preferred embodiment of the present invention, in S4, the process of ball - milling activation is as follows: by mass fraction, take 20 - 50 parts of the mixture of the first water - containing coal slime and the second water - containing coal slime, 5 - 30 parts of aluminosilicate minerals, 0.1 - 1 part of a stearic acid - based modifier, 50 - 150 parts of ball - milling beads, mix them evenly, ball - mill for 1 - 10 h, remove the ball - milling beads, and obtain activated coal slime with a particle specific surface area reaching 450 - 550 m 2 / kg.

[0027] According to a preferred embodiment of the present invention, in S4, the preparation method of the coal mine underground plugging material is as follows: take 20 - 40 mass parts of activated coal slime, 15 - 25 mass parts of silicate cement, 2 - 5 mass parts of early - strength and fast - hardening cement, 1 - 3 mass parts of soluble silicate, 0.2 - 0.8 mass parts of polycarboxylate - based water - reducing agent, 12 - 20 mass parts of water - based emulsion, 0.01 - 0.1 mass parts of lithium carbonate, 1 - 10 mass parts of water, stir at a high speed of 1000 - 3000 rpm for 20 - 40 min to obtain the coal mine underground plugging material; the water - based emulsion is one or several of acrylic emulsion, silanized polymer emulsion, polyurethane emulsion, polyacrylate emulsion, water - based resin emulsion, and polyvinyl acetate emulsion.

[0028] Preferably, the aluminosilicate minerals are one or several of kaolin, feldspar, mica, olivine, garnet, andalusite, epidote, pyroxene, amphibole, wollastonite, talc, kaolinite, chlorite, and serpentine.

[0029] According to a preferred embodiment of the present invention, the preparation method of the goaf backfill grouting material is as follows: take 20 - 35 mass parts of activated coal slime, 50 - 70 mass parts of the third mixed slag, 0 - 80 mass parts of slag aggregate, 4 - 10 mass parts of drilling mud material, 1 - 5 mass parts of water - soluble binder; add water to prepare a goaf backfill grouting material with a solid content of 75 - 85%.

[0030] Among them, the addition amount of the slag and stone aggregate is related to the third mixed slag. If the main component of the third mixed slag is crop straw ash slag, the amount of the slag and stone aggregate needs to be increased; if the main component of the third mixed slag is boiler coal slag adsorbent, less or no slag and stone aggregate can be added. The slag and stone aggregate is particles such as gangue produced by coal mining, etc., with a particle size of 0.001 - 5 mm. The drilling mud material is a commercially available product, and the water-soluble binder is CMC or polyvinyl alcohol or HEC.

[0031] (III) Beneficial effects

[0032] For the comprehensive treatment method of coal mine well water of the present invention, on the one hand, it can greatly reduce the SS value of the coal mine well water and reduce the heavy metal content contained therein, so that the produced water can meet the requirements of non-drinking and irrigation. On the other hand, for the coal mine well water with a high SS content, it does not need to be transported outside the well; the step of separating SS in the coal mine well water is completed underground, and the produced water-containing coal slime can be made into underground plugging materials or grouting materials for backfilling goafs, so the transportation cost and the wear of the conveying equipment caused by high solids can be greatly reduced. The inclined plate sedimentation tank and the microsand enhanced flocculation sedimentation tank designed by the present invention are box structures made of fiberglass or metal plates or high-hardness resin materials, and have the advantages of small volume, small floor area, high treatment efficiency, low cost, fast start-up, low chemical agent cost, etc., and are very suitable for completing the efficient treatment process of coal mine well water of S1 - S2 underground in coal mines. In S3, an adsorbent is made from crop straw ash slag or boiler coal slag to remove a small amount of oil, acid-base ions or heavy metal ions in the water, so that the third treated water meets the requirements of non-drinking water, such as construction water, irrigation water, heating water, etc., and avoids corrosion to the equipment. And the crop straw ash slag or boiler coal slag is a degradable material, so that the third mixed slag can be used to make grouting backfill materials for goafs underground in coal mines or be mixed with cement to make concrete to build an underground protective support body, which not only has low cost, but also can realize the secondary utilization of waste materials and harmless landfill, and will not cause non-degradable pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a flow chart of the comprehensive treatment method of coal mine well water of the present invention.

[0034] Figure 2 is a schematic diagram of the inclined plate sedimentation tank in step S1 of the treatment method.

[0035] Figure 3 is a schematic diagram of the microsand enhanced flocculation sedimentation tank in step S2 of the treatment method. DETAILED DESCRIPTION OF THE INVENTION

[0036] In order to better explain the present invention for easy understanding, the present invention will be described in detail below with reference to the drawings through specific embodiments.

[0037] AsFigure 1 As shown in the figure, the present invention provides a comprehensive treatment method for coal mine well water, including the following steps:

[0038] S1. The coal mine well water is subjected to sedimentation separation to produce first water-containing coal slime and first treated water.

[0039] No energy consumption is used for sedimentation separation, and separation is formed by the gravity of insoluble particulate matters in the coal mine well water. First, the coal mine well water is pumped into a water collecting tank arranged underground in the mine. The water collecting tank is an inclined plate sedimentation tank, and the first water-containing coal slime is discharged from the lower part of the inclined plate sedimentation tank. The inclined plate sedimentation tank outputs the first treated water. Among them, the SS of the coal mine well water is 10,000 - 15,000 mg / L, and the oil content is 100 - 4,000 mg / L.

[0040] S2. The first treated water is purified to produce second water-containing coal slime and second treated water.

[0041] A coagulant is added to the first treated water, and it is treated by a microsand enhanced flocculation sedimentation tank to obtain second water-containing coal slime and second treated water.

[0042] S3. The second treated water is purified to produce third mixed slag and third treated water; the third treated water is used as non-drinking domestic water or construction water.

[0043] The second treated water is adsorbed and purified by using crop straw ash residue or boiler coal slag. After the drained water is filtered, third mixed slag and third treated water are obtained.

[0044] S4. The first water-containing coal slime and the second water-containing coal slime are combined and ball mill activated underground to obtain activated coal slime, and the activated coal slime is used to prepare coal mine underground plugging materials; or the activated coal slime and the third mixed slag are made into goaf backfill grouting materials.

[0045] Such as Figure 2As shown in the figure, the inclined plate sedimentation tank 1 is made of fiberglass, metal plate or high-hardness resin material. Preferably, the total depth of the inclined plate sedimentation tank 1 is 1.5 - 2.0 m, the length is 6 - 10 m, and the width is 1.5 - 2.5 m. A scum removal mechanism 2 is provided above the inclined plate sedimentation tank 1 to remove insoluble solids or oil floating on the surface of the coal mine well water through the scum removal mechanism 2. The inclined plate sedimentation tank 1 includes an inclined plate group with a thickness of 0.85 m. The inclined plate group includes a number of inclined plates 111, and each inclined plate 111 is arranged in an inclined and parallel-spaced manner. The bottom sludge discharge port of the inclined plate sedimentation tank 1 is used to discharge the first water-containing coal slime. The water inlet 12 of the inclined plate sedimentation tank 1 is located below the horizontal midline of the inclined plate group, and the water inlet cannot directly reach below the inclined plate group. It must flow downward from above the inclined plate group through the gaps between the inclined plates to reach below the inclined plate group. An overflow wall 13 is provided at the upper end of the side of the inclined plate sedimentation tank 1 opposite to the water inlet. The overflow wall 13 is connected to an overflow trough 131. The overflow trough 131 is provided with a water outlet 132, and the water outlet 132 outputs the first treated water. However, the overflow trough 131 is not directly connected to the clear water above the inclined plate group. That is, the clear water above the inclined plate group must pass through the gaps in the inclined plate group and overflow upward from below the inclined plate group over the overflow wall 13 before it can be discharged. This structure can increase the water flow path, improve the sedimentation efficiency, and increase the treatment capacity of the sedimentation tank per unit volume. The scum removal mechanism 2 includes a conveyor belt 21 and a scraper 22 provided on the conveyor belt 21. The conveyor belt 21 includes a first section 211 and a second section 212. Its first section 211 is parallel to the liquid level of the inclined plate sedimentation tank 1, and the second section 212 is located at the end of the conveyor belt 21 and is inclined upward relative to the first section 211. The second section 212 is close to the edge of the inclined plate sedimentation tank 1. A slope 14 is provided on one side of the upper end of the inclined plate sedimentation tank 1, and the slope 14 is correspondingly parallel to the second section 212. As the conveyor belt 21 rotates, it drives the scraper 22 to move parallel above the liquid level of the inclined plate sedimentation tank 1. When the scraper 22 reaches the second section 212, it starts to move upward along the slope 14 to discharge the insoluble solids or oil floating on the surface of the coal mine well water from the slope 14 of the inclined plate sedimentation tank 1.

[0046] As Figure 3As shown in the figure, the microsand enhanced flocculation sedimentation tank 4 includes a tank body 41 made of fiberglass, metal plate or high-hardness resin material. Preferably, the length of the tank body 41 is 4-7m, the depth is 1.4-2.0m, and the width is 1.2-2m. An inlet 411 is provided at the bottom of one side of the tank body 41, and no first partition 410, second partition 420 and third partition 430 are provided inside the tank body 41. The first partition 410 is installed at the bottom of the tank body 41 and extends upward but is not connected to the top of the tank body. The second partition 420 is installed at the top of the tank body 41 and extends downward but is not connected to the bottom of the tank body. The third partition 430 is installed at the bottom of the tank body 41 and extends upward but is not connected to the top of the tank body, whereby a connected waterway is still formed inside the tank body 41. The first partition 410 and one end side wall of the tank body 41 form an inlet area A; the area between the second partition 420 and the first partition 410 forms a sand addition area B; the area between the second partition 420 and the third partition 430 forms a transition area C, and the third partition 430 and the other end side wall of the tank body 41 form an enhanced sedimentation area D. A coagulant dosing port is provided in the inlet area A, and a microsand feeding port and a polymer coagulant aid dosing port are provided in the sand addition area B; an inclined tube assembly 5 is provided above the enhanced sedimentation area D, and the whole of the inclined tube assembly 5 is immersed below the water surface. Above the inclined tube assembly is a clear water area E. An outlet 412 communicating with the clear water area E is provided at the upper part of the tank body 41 for discharging the secondary treated water. A sediment circulation port 413 is provided at the bottom of the enhanced sedimentation area D, a sand leakage net 44 is provided above the sediment circulation port 413, and a sludge scraper 45 is provided above the sand leakage net 44. The sludge scraper 45 is driven by a motor. By pushing to generate friction between the sediment and sand, the sludge attached to the surface of the microsand is scraped off, and then the sand with a smaller particle size falls into the sediment circulation port 413 of the sand leakage net 44 and is collected and added back to the sand addition area B. The larger scraped sludge is deposited in flakes at the bottom of the enhanced sedimentation area D. A sludge discharge port 414 is provided at the bottom of the tank body 41 for discharging the secondary water-containing coal slime. As Figure 3As shown, there is no agitator in the water inlet area A, sand addition area B, and transition area C, while a sludge scraper 45 is provided in the enhanced sedimentation area D. The sludge scraper 45 is driven by a motor and pushes the fine sand carrying mud flakes deposited on the sand leakage net 44 at the bottom of the enhanced sedimentation area D. The mud and sand circulation port 413 is connected to the mud and sand circulation pump 416, and with the help of the mud and sand circulation pump 416, the mud and sand are introduced into the hydrocyclone 46. After the fine sand and mud are separated again by the hydrocyclone 46, the fine sand is added back to the sand addition area B. The mud separated by the hydrocyclone 46 is discharged and merged with the second water-containing coal slime discharged from the mud discharge port 414 for making grouting materials for underground plugging in the mined-out area. The working principle of the fine sand enhanced flocculation sedimentation tank 4 is a physicochemical treatment process that uses continuously circulating fine sand particles and chemical agents to enhance floc adsorption to improve the sedimentation performance of suspended solids in water. A coagulant is added to the water in the water inlet area A to destabilize the suspended solids and colloidal particles in the water. Then, a polymer flocculant and fine sand carrier particles with a relatively large density are added in the sand addition area B, so that the destabilized impurity particles use the carrier as the floc nucleus, and through the bridging adsorption effect of the polymer chain and the deposition and trapping effect of the fine sand particles, large-density flocs are quickly generated. Under the efficient separation of the inclined tube assembly 5 in the enhanced sedimentation area D, the sedimentation time is greatly shortened and the treatment effect is improved. The bottom mud and sand are refluxed, and through the combined action of frictional pushing and the hydrocyclone, the fine sand and the upper mud blocks are separated, and the fine sand is recycled for reuse.

[0047] Furthermore, the second treated water produced by the fine sand enhanced flocculation sedimentation tank 4 is adsorbed and purified using biodegradable materials such as crop straw ash or boiler coal slag to remove corrosive ions or heavy metal ions. The crop straw ash is obtained by crushing crop straw (such as wheat straw, rice straw, soybean straw, corn stalks, etc.), compressing it into a mold, and burning it in an incinerator. The heat generated by the incineration can supply the heating equipment in the mining area, and the straw ash is used as an adsorbent to treat acid-base ions (removing corrosion) or heavy metal ions in water. The boiler coal slag is made into a coal slag ash adsorption material and then used according to the following method: Take industrial boiler coal slag and crush it into 100 - 150 mesh; mix the boiler coal slag and cement in a mass ratio of 5 - 10:1, granulate, and calcine to obtain the boiler coal slag adsorption material. The water treated through S3 basically meets the requirements of heating water, construction water, etc.

[0048] Finally, the coal slime and solid slag obtained from the above treatment are further utilized. The utilization methods include mixing with a small amount of cement to make underground plugging materials for coal mines, or making grouting materials for backfilling mined-out areas with drilling mud materials:

[0049] First, activate the coal slime by ball milling: In the process of ball milling activation, take 20 - 50 parts by mass of the mixture of the first water-containing coal slime and the second water-containing coal slime, 5 - 30 parts of aluminosilicate minerals, 0.1 - 1 part of stearic acid-based modifier, and 50 - 150 parts of ball milling beads, mix them evenly, ball mill for 1 - 10 h, remove the ball milling beads, and obtain activated coal slime with a particle specific surface area reaching 450 - 550 m 2 / kg.

[0050] Among them, the preparation method of the underground coal mine plugging material is as follows: Take 20 - 40 parts by mass of activated coal slime, 15 - 25 parts by mass of portland cement, 2 - 5 parts by mass of early strength and rapid hardening cement, 1 - 3 parts by mass of soluble silicate, 0.2 - 0.8 parts by mass of polycarboxylate-based water reducer, 12 - 20 parts by mass of water-based emulsion (the solid content of the emulsion is 37 - 50%), 0.01 - 0.1 parts by mass of lithium carbonate, and 1 - 10 parts by mass of water, stir at a high speed of 1000 - 3000 rpm for 20 - 40 min to obtain the underground coal mine plugging material; the water-based emulsion is one or more of acrylic emulsion, silanized polymer emulsion, polyurethane emulsion, polyacrylate emulsion, water-based resin emulsion, and polyvinyl acetate emulsion.

[0051] Preferably, the aluminosilicate minerals are one or more of kaolin, feldspar, mica, olivine, garnet, andalusite, epidote, pyroxene, amphibole, wollastonite, talc, kaolinite, chlorite, and serpentine.

[0052] Among them, the preparation method of the gob backfill grouting material is as follows: Take 20 - 35 parts by mass of activated coal slime, 50 - 70 parts by mass of the third mixed slag, 0 - 80 parts by mass of slag stone aggregate, 4 - 10 parts by mass of drilling mud material, and 1 - 5 parts by mass of water-soluble binder; add water to prepare a gob backfill grouting material with a solid content of 75 - 85%.

[0053] Among them, the addition amount of the slag stone aggregate is related to the third mixed slag. If the main component of the third mixed slag is crop straw ash slag, the amount of the slag stone aggregate needs to be increased; if the main component of the third mixed slag is boiler coal slag adsorption material, less or no slag stone aggregate can be added. The slag stone aggregate is particles such as gangue produced by coal mining, etc., with a particle size of 0.001 - 5 mm. The drilling mud material is a commercially available product, and the water-soluble binder is CMC or polyvinyl alcohol or HEC.

[0054] Example 1

[0055] This example provides a comprehensive treatment method for coal mine water, including the following steps:

[0056] (1), Feed the coal mine water into Figure 2The inclined plate sedimentation tank 1 shown in the figure is processed, left standing for 20 h, to produce the first water-containing coal slime and the first treated water. A large amount of insoluble solid slag and a small amount of oil are scraped off from above the inclined plate sedimentation tank 1. The SS of the coal mine well water is 10,000 mg / L, and the oil content is 1,064 mg / L.

[0057] (2) The first treated water is fed into Figure 3 the microsand enhanced flocculation sedimentation tank shown in the figure for treatment, to obtain the second water-containing coal slime and the second treated water.

[0058] (3) The second treated water is treated using straw ash residue and boiler coal slag ash adsorption materials as adsorbents. The straw ash residue is obtained by crushing corn stalks, compressing them into a mold, and burning them in an incinerator. The boiler coal slag is made into a coal slag ash adsorption material according to the following method before use: Take industrial boiler coal slag, crush it into 100 meshes; mix the boiler coal slag and cement in a mass ratio of 8:1, granulate, and calcine to obtain the boiler coal slag adsorption material. The second treated water is put into a storage tank, and the straw ash residue and the boiler coal slag adsorption material are added. The water, straw ash residue, and boiler coal slag adsorption material are mixed in a volume ratio of 10:2.5:1. After adsorption for 12 h, plate and frame filtration is carried out to produce the third mixed slag and the third treated water. The SS of the third treated water ≤ 50 mg / L, and the oil content ≤ 5 mg / L. This water basically meets the requirements for heating water, concrete construction water, etc.

[0059] (4) The first water-containing coal slime and the second water-containing coal slime are combined and ball mill activated underground to obtain activated coal slime, which is used to prepare the coal mine underground plugging material.

[0060] First, by mass fraction, take 35 parts of the mixture of the first water-containing coal slime and the second water-containing coal slime, 15 parts of kaolin, 0.2 part of magnesium stearate modifier, and 50 parts of ball mill beads, mix them evenly, ball mill for 6 h, remove the ball mill beads, and obtain activated coal slime with a specific surface area of about 480 m 2 / kg.

[0061] By mass fraction, take 30 parts of activated coal slime, 18 parts of P.O42.5R Portland cement, 2.5 parts of early strength and rapid hardening cement, 1.5 parts of sodium silicate, 0.3 part of polycarboxylate-based water reducer, 15 parts of acrylic emulsion, 0.02 part of lithium carbonate, and 4 parts of water, stir at a high speed of 1200 rpm for 30 min to prepare the coal mine underground plugging material. This plugging material is used to plug the concrete test brick with cracks on the surface. First, clean the surface of the brick, and then quickly pour the plugging material into the cracks on the surface of the concrete test brick. The setting time is tested to be 17 min, the flexural strength at 7 d is 8.9 Mpa, the bonding strength is 0.69 Mpa, and the impermeability grade is W10.

[0062] Example 2

[0063] The difference between Example 2 and Example 1 is that the activated slime with a specific surface area of about 480 m 2 / kg prepared in step (4) is made into a gob backfill grouting material. The method is as follows: take 35 parts by mass of activated slime, 40 parts by mass of the third mixed slag, 20 parts by mass of slag gangue particles (particle size 0.001 - 5 mm), 10 parts by mass of drilling mud material, and 4 parts by mass of CMC; add water to prepare a gob backfill grouting material with a solid content of 75%. The grouting material is tested to have good fluidity and a large diffusion radius, showing non-Newtonian fluid characteristics, and is suitable as a grouting backfill material for grouting and backfilling the gob.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A comprehensive treatment method for coal mine well water, characterized in that, It includes the following steps: S1. Coal mine well water sedimentation and separation: The coal mine well water is introduced into an inclined plate sedimentation tank for treatment. The first water-containing coal sludge is discharged from the bottom of the inclined plate sedimentation tank. A scum removal mechanism is provided above the inclined plate sedimentation tank to remove insoluble solids or oil floating on the surface of the coal mine well water. The inclined plate sedimentation tank outputs the first treated water. The SS of the coal mine well water is 10,000 - 15,000 mg / L, and the oil content is 100 - 4,000 mg / L. S2. Purification of the first treated water: A coagulant is added to the first treated water, and it is treated with a microsand enhanced flocculation sedimentation tank to obtain the second water-containing coal sludge and the second treated water. S3. Purification of the second treated water: Crop straw ash or boiler coal slag is used to adsorb and purify the second treated water. After the drained water is filtered, the third mixed slag and the third treated water are obtained. The third treated water is used as non-drinking domestic water or construction water. S4. The first water-containing coal sludge and the second water-containing coal sludge are combined and ball mill activated underground to obtain activated coal sludge, and the activated coal sludge is used to prepare plugging materials for coal mines underground; or the activated coal sludge and the third mixed slag are made into backfill grouting materials for goafs.

2. The comprehensive treatment method for coal mine well water according to claim 1, characterized in that, In S3, the SS of the third treated water ≤ 50 mg / L, and the oil content ≤ 5 mg / L.

3. The comprehensive treatment method for coal mine well water according to claim 1, characterized in that, In S1, the inclined plate sedimentation tank is made of metal plates or high-hardness resin materials. The scum removal mechanism is arranged above the inclined plate sedimentation tank and includes a conveyor belt and a scraper arranged on the conveyor belt. The conveyor belt includes a first section and a second section. Its first section is parallel to the liquid level of the inclined plate sedimentation tank. The second section is located at the end of the conveyor belt and is inclined upward relative to the first section. A slope is provided on one side of the upper end of the inclined plate sedimentation tank, and this slope corresponds to and is parallel to the second section. Through the rotation of the conveyor belt, the scraper is driven to move above the liquid level of the inclined plate sedimentation tank, and the insoluble solids or oil floating on the surface of the coal mine well water are discharged from the slope of the inclined plate sedimentation tank.

4. The comprehensive treatment method for coal mine well water according to claim 3, characterized in that, The inclined plate sedimentation tank includes an inclined plate group. Each inclined plate in the inclined plate group is arranged in an inclined and parallel and spaced manner. The bottom sludge discharge port of the inclined plate sedimentation tank is used to discharge the first water-containing coal sludge. And the water inlet of the inclined plate sedimentation tank is arranged at a position slightly below the horizontal midline of the inclined plate group. An overflow wall is provided at the upper end of the side of the inclined plate sedimentation tank opposite to the water inlet. The overflow wall is connected to an overflow tank. The overflow tank is provided with a water outlet, and the first treated water is output from this water outlet. The overflow tank is not directly connected to the clear water above the inclined plate group.

5. The comprehensive treatment method for coal mine well water according to claim 1, characterized in that, In S2, the microsand enhanced flocculation sedimentation tank includes a tank made of metal plates or high-hardness resin materials. An inlet is provided at the bottom of one side of the tank. The tank is internally provided with a first partition board, a second partition board, and a third partition board. Among them, the first partition board is installed at the bottom of the tank and extends upward but is not connected to the top of the tank. The second partition board is installed at the top of the tank and extends downward but is not connected to the bottom of the tank. The third partition board is installed at the bottom of the tank and extends upward but is not connected to the top of the tank. The first partition plate and one end side wall of the tank form an inlet area; the area between the second partition plate and the first partition plate forms a sand adding area; the area between the second partition plate and the third partition plate forms a transition area, and the third partition plate and the other end side wall of the tank form a strengthened sedimentation area; the inlet area is provided with a coagulant dosing port, and the sand adding area is provided with a fine sand feeding port and a polymer coagulant aid dosing port; an inclined tube assembly is arranged above the strengthened sedimentation area, the inclined tube assembly is immersed below the water surface, the upper part of the inclined tube assembly is a clear water area, and a water outlet communicating with the clear water area is arranged at the upper part of the tank for discharging the secondary treated water; A sediment circulation port is arranged at the bottom of the strengthened sedimentation area, a sand leakage net is arranged above the sediment circulation port, and a sludge scraper is arranged above the sand leakage net. The sludge scraper generates friction between the sediments to scrape off the sludge on the surface of the fine sand, and the fine sand with a reduced particle size falls into the sediment circulation port of the sand leakage net. The scraped sludge is deposited in flakes at the bottom of the strengthened sedimentation area. A sludge discharge port is arranged at the bottom of the tank for discharging the secondary water-containing coal slime.

6. The comprehensive treatment method for coal mine well water according to claim 5, characterized in that, In S3, the crop straw ash residue is obtained by crushing crop straws, compressing them into a mold, and burning them. The crop straw ash residue is used as an adsorbent to treat acid-base ions or heavy metal ions in water; The boiler cinder is made into a cinder ash adsorbent material according to the following method and is used to treat acid-base ions or heavy metal ions in water: Take industrial boiler cinders and crush them into 100-150 mesh; mix the boiler cinders and cement in a mass ratio of 5-10:1, granulate them, and calcine them to obtain a boiler cinder adsorbent material.

7. The comprehensive treatment method for coal mine well water according to claim 1, characterized in that, In S3, the non-potable domestic water includes heating water or irrigation water; the construction water includes concrete construction water.

8. The comprehensive treatment method for coal mine well water according to claim 1, characterized in that, In S4, the process of ball-milling activation is as follows: by mass parts, take 20 - 50 parts of the mixture of the first water-containing slime and the second water-containing slime, 5 - 30 parts of aluminosilicate minerals, 0.1 - 1 part of stearic acid-based modifier, and 50 - 150 parts of ball-milling beads, mix them evenly, ball-mill for 1 - 10 h, remove the ball-milling beads, and obtain activated slime with a particle specific surface area reaching 450 - 550 m 2 / kg.

9. The comprehensive treatment method for coal mine well water according to claim 8, characterized in that, In S4, the preparation method of the goaf backfill grouting material is as follows: take 20-35 parts by mass of activated coal slime, 50-70 parts by mass of the third mixed slag, 0-80 parts by mass of slag aggregate, 4-10 parts by mass of drilling mud material, and 1-5 parts by mass of water-soluble binder; add water to prepare a goaf backfill grouting material with a solid content of 75-85%.

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