Underground negative pressure sand suction device and method for in-situ leaching uranium mining

Abstract

The invention provides an in-situ leaching uranium mining underground negative pressure sand suction device, and relates to the technical field of in-situ leaching uranium mining, the in-situ leaching uranium mining underground negative pressure sand suction device comprises an air pipe joint, and the air pipe joint is connected to the tail end of an air pipe; the partial pressure column is connected to the lower end of the air pipe joint; the pressure release valve is arranged at the lower end of the pressure dividing column; one end of the discharge injection inclined pipe is connected to the side face of the partial pressure column; the three-phase mixing column is parallel to the partial pressure column, and the other end of the discharge injection inclined pipe is connected to the side face of the three-phase mixing column; the rotary sand suction head is arranged at the lower end of the three-phase mixing column, and a plurality of slits are obliquely formed in the side face of the rotary sand suction head; and the sand stirring assembly is connected to the pressure release valve. According to the device, sand-carrying liquid is conveyed through the grouting pipe, the wellhead liquid-solid two-phase flow velocity is increased, the underground sand removal efficiency is improved, the rotary sand suction head can control the proportion of sucked particles, and the problems that the grouting pipe is blocked, the gas lift negative pressure is insufficient, and the particles fall back due to straight-through type opening sand suction are solved.

Description

Technical Field

[0001] The invention relates to the technical field of in-situ leaching of uranium, and in particular to a negative pressure sand suction device and method for in-situ leaching of uranium. Background Art

[0002] In-situ leaching of uranium is the main mining process for natural uranium in my country. The uranium-containing leaching solution is lifted from the boreholes to the ground through numerous extraction boreholes and then undergoes a series of treatment processes. Sand production is a common problem underground in each borehole, and the boreholes need to be washed and desanded to restore the permeability of the ore layer and ensure the normal amount of liquid pumped.

[0003] At present, air compressors are commonly used in mines and other production sites to wash wells and remove sand, but there are the following problems:

[0004] In deep wells, due to the buoyancy of the liquid, it is difficult to lower the air duct all at once by manpower. Usually, compressed air is introduced to drain the liquid first, and then it is lowered several times to the ore layer.

[0005] This method is relatively extensive. The underground sand is lifted to the surface in the form of plug flow. The three-phase flow velocity is slow, resulting in poor sand carrying effect. It takes a long time to complete sand removal, which is inefficient and has high energy consumption. Summary of the invention

[0006] The purpose of the present invention is to provide a negative pressure sand suction device and method for in-situ leaching of uranium to improve the above problems. In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present application provides a negative pressure sand suction device for in-situ leaching of uranium, comprising:

[0008] An air duct joint, the air duct joint being connected to the end of the air duct;

[0009] A pressure dividing column connected to the lower end of the air duct joint;

[0010] A pressure relief valve, the pressure relief valve being arranged at the lower end of the pressure dividing column;

[0011] A discharge and injection inclined tube, one end of which is connected to the side of the pressure dividing column;

[0012] A three-phase mixing column, wherein the three-phase mixing column is parallel to the pressure dividing column, and the other end of the discharge and injection inclined pipe is connected to the side of the three-phase mixing column;

[0013] A rotary sand suction head, which is arranged at the lower end of the three-phase mixing column and has a plurality of slits obliquely opened on the side thereof;

[0014] A sand stirring assembly is connected to the pressure relief valve.

[0015] Optionally, the angle between the discharge and injection inclined tube and the pressure dividing column is ≤60°, and the outer diameter of the discharge and injection inclined tube is ≤40 mm. The angle between the injection inclined tube and the pressure dividing column is calculated based on the inner diameter of the injection inclined tube and the inner diameter of the three-phase mixing column.

[0016] Optionally, the slit is opened obliquely along the surface of the rotary sand suction head.

[0017] Optionally, the angle between the slit and the axis of the three-phase mixing column is ≥60°, the slit width is 0.5mm-2mm, and the slit length is ≥2cm. The total slit area of ​​the rotary sand suction head is calculated from the inner diameter of the jet inclined tube and the inner diameter of the three-phase mixing column.

[0018] Optionally, a one-way valve plate is provided inside the three-phase mixing column, and the one-way valve plate is located below the connection between the three-phase mixing column and the discharge and injection inclined pipe.

[0019] Optionally, the sand stirring assembly includes a sand stirring blade and a blade bracket, the sand stirring blade is connected to the pressure dividing column and / or the rotary sand suction head through the blade bracket, and the sand stirring blade is connected to the pressure relief valve through an air pipe.

[0020] Optionally, the distance between the upper end of the sand stirring blade and the rotary sand suction head is ≤300 mm.

[0021] Optionally, the sand stirring blade is a three-blade propeller.

[0022] Optionally, the upper end of the three-phase mixing column is connected to a grouting pipe joint, the outer diameter of the grouting pipe joint is ≤50mm, and the outer diameter of the three-phase mixing column is ≤40mm.

[0023] In a second aspect, the present application further provides a method for negative pressure sand suction in an in-situ uranium leaching well, the method being implemented based on the above-mentioned negative pressure sand suction device in an in-situ uranium leaching well, comprising:

[0024] According to the downhole TV observation results and the filter position, the total height of the downhole sand settling is determined, and the initial lowering position of the negative pressure sand suction device in the in-situ leaching uranium well is calculated; the static water level data is collected to calculate the static liquid column pressure at the sand suction position;

[0025] adjusting the working parameters of the pressure relief valve according to the hydrostatic column pressure;

[0026] According to the initial lowering position, the negative pressure sand suction device for in-situ leaching uranium is lowered into the well and fixed at the wellhead;

[0027] Perform sand removal operation, take samples at a fixed frequency, measure the particle content in the sucked-out material, and when the particle content is reduced to less than 30% of the initial working condition, suspend sand removal and continue to lower it for 50-100cm. Repeat this cycle, and the total lowering depth does not exceed the total height of sand settling.

[0028] The beneficial effects of the present invention are:

[0029] The negative pressure sand suction device and method for in-situ uranium leaching of the present application use a grouting pipe to transport sand-carrying liquid, which greatly increases the liquid-solid two-phase flow rate at the wellhead and improves the sand removal efficiency in the well. The rotary sand suction head arranged at the bottom of the device is used in combination with a sand stirring component to first stir up the settled sand and fully mix it with the liquid phase, and then suck it into the three-phase mixing column along the rotary slit, so that the proportion of sucked particles can be controlled, and the blockage of the grouting pipe caused by straight-through opening sand suction and the falling back of particles along the inner wall of the grouting pipe caused by insufficient negative pressure of air lift can be avoided. Moreover, the air duct can be lowered together with the grouting pipe through a drilling rig or a crane, which solves the problem that the air duct cannot be lowered all at once due to buoyancy when a conventional air compressor is used to wash the well.

[0030] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the working state of the negative pressure sand suction device for in-situ leaching of uranium in an embodiment of the present application;

[0032] Figure 2 This is a schematic diagram of the structure of a negative pressure sand suction device for in-situ leaching of uranium in an embodiment of the present application;

[0033] Figure 3 This is a schematic diagram of the slit structure of the rotary sand suction head according to an embodiment of the present application.

[0034] Explanation of symbols: 1. Air compressor; 2. Casing; 3. Air duct; 401. Jet inclined pipe; 402. Air duct joint; 403. Pressure dividing column; 404. Pressure relief valve; 405. Blade bracket; 406. Air pipe; 407. Sand stirring blade; 408. Rotary sand suction head; 409. Three-phase mixing column; 410. One-way valve plate; 411. Grouting pipe joint; 5. Filter; 6. Sand settling; 7. Sand settling pipe; 8. Grouting pipe. DETAILED DESCRIPTION

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0036] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0037] Under the existing drilling structure and technical conditions, underground sand gushing is inevitable, so the removal of underground sand has gradually become the main task of well site operation and maintenance.

[0038] At present, the main method of cleaning sediment is to rely on various well washing processes. Air compressor well washing, piston well washing and submersible pump well washing are commonly used in mines and other production sites.

[0039] Among them, piston well washing is achieved by lowering a plunger in the casing, and performing piston movement in the casing through the traction of a wire rope. When the piston is lifted, the ore layer is subjected to negative pressure, and the sand and blockages are sucked out. When the piston is lowered next time, part of the sand is transported to the upper part of the piston, and is lifted to the ground with the liquid when it is lifted up. It is gradually cleaned up in the continuous reciprocating motion. However, this sand removal process has high requirements on the cementing quality, and is prone to problems such as casing run-up and coupling leakage, which have an adverse effect on the sand removal effect, and the operation is difficult when the well is deep.

[0040] Submersible pump well washing is a method of disturbing the sand by changing the flow of liquid in the well through the suction force at the suction end of the submersible pump. The sand and liquid enter the submersible pump together and are then lifted to the surface. Due to the great depth of the ore layer in recent years, the submersible pump cannot go down to the bottom of the well to pump out the sand. Therefore, the sand removal efficiency of this method is too low, and when the sand content is too high, the impeller of the submersible pump is easily damaged. In addition, the huge amount of water lifted to the surface needs to be separated into solid and liquid and injected back into the well. The cost of a high-lift and large-flow submersible pump is about 20,000 to 30,000 yuan, and the cost of repair after damage remains high.

[0041] There are two key points to using an air compressor to wash a well: first, to create negative pressure, so that water flows in from the outside of the filter at a relatively fast speed, sucking out the fine particles attached to the filter and the gravel layer, thereby improving the water permeability of the filter; second, to inject compressed air through the ore layer in a directional manner, stirring the bottom sand and other impurities through high-speed gas-liquid plug flow and lifting them to the surface. This process requires the air duct to be lowered to a large depth (usually directly to the ore layer) to generate a large hydraulic pressure difference.

[0042] Example 1

[0043] See also Figure 1 and Figure 2 The present application provides a negative pressure sand suction device for in-situ leaching of uranium, comprising:

[0044] An air duct joint 402, the air duct joint 402 is connected to the end of the air duct 3;

[0045] A pressure dividing column 403, wherein the pressure dividing column 403 is connected to the lower end of the air duct joint 402;

[0046] A pressure relief valve 404, wherein the pressure relief valve 404 is disposed at the lower end of the pressure dividing column 403;

[0047] An injection inclined tube 401, one end of which is connected to the side of the pressure dividing column 403;

[0048] A three-phase mixing column 409, wherein the three-phase mixing column 409 is parallel to the pressure dividing column 403, and the other end of the injection inclined tube 401 is connected to the side of the three-phase mixing column 409; the injection inclined tube 401 extends obliquely upward from the side of the pressure dividing column 403;

[0049] A rotary sand suction head 408, which is disposed at the lower end of the three-phase mixing column 409 and has a plurality of slits obliquely opened on the side thereof;

[0050] A sand stirring assembly, wherein the sand stirring assembly is connected to the pressure relief valve 404 .

[0051] The grouting pipe 8 and the air duct 3 are both commonly used devices at drilling sites. The present application designs a sand removal device based on this, with a low investment cost. The grouting pipe 8, the underground negative pressure sand suction device and the air duct 3 can be connected in advance on the ground, and the air duct 3 can be lowered into the casing 2 together with the grouting pipe 8 through a drilling rig or a crane. The end of the casing 2 is a filter 5, and the filter 5 is lowered to form a sand settling pipe 7. The lowering depth is determined in combination with the underground television observation results and the position of the filter 5, which is usually 0.5-1m above the sand settling 6.

[0052] Preferably, the outer diameter of the negative pressure sand suction device for in-situ leaching uranium mining is ≤110 mm, so as to ensure smooth construction in an in-situ leaching process well with an inner diameter of 128 mm.

[0053] As an optional embodiment, the air duct joint 402 is made of brass or stainless steel, with a maximum outer diameter of ≤50mm and a pressure resistance of ≥10MPa; its lower end is welded to the pressure dividing column 403, and the upper end is threadedly connected to the end of the air duct 3, and the other end of the air duct 3 is connected to the air compressor 1 to transmit the high-pressure gas generated by the air compressor 1 to the pressure dividing column 403.

[0054] As an optional implementation, the pressure dividing column 403 is made of 304 stainless steel, the outer diameter of the pressure dividing column 403 is ≤40mm, and the pressure resistance is ≥10MPa; the pressure dividing column 403 has an opening at the upper end, side and lower end respectively, and the three openings are respectively connected to the air duct joint 402, the injection inclined tube 401, and the pressure relief valve 404.

[0055] The injection inclined tube 401 is used to connect the pressure dividing column 403 and the three-phase mixing column 409 to transmit the high-pressure gas to the three-phase mixing column 409. It is connected to the pressure dividing column 403 and the three-phase mixing column 409 by welding. The angle between the injection inclined tube 401 and the pressure dividing column 403 is ≤60°, the outer diameter of the injection inclined tube 401 is ≤40mm, and the pressure resistance is ≥10MPa.

[0056] The angle between the injection inclined tube 401 and the pressure dividing column is calculated by the inner diameter of the injection inclined tube 401 and the inner diameter of the three-phase mixing column 409, and the relationship is as follows:

[0057] d p =d 三相混合柱内径 / (tanθ·(tan 2 θ+1) 0.5 )

[0058] Among them, d p is the inner diameter of the jet inclined tube 401, d 三相混合柱内径 is the inner diameter of the three-phase mixing column 409, and θ is the angle between the injection inclined tube 401 and the partial pressure column;

[0059] This relationship can ensure that the horizontal component of the gas ejected from the injection inclined tube 401 matches the inner diameter of the three-phase mixing column 409, and the vertical component is much larger than the critical pressure and gas volume for opening the pressure relief valve 404, so that the two reach a good balance.

[0060] As an optional implementation, the pressure relief valve 404 is made of brass or stainless steel, and the pressure relief adjustment range is 2-6MPa. Its air inlet end is connected to the pressure divider column 403 with M15-M21 threads, and the lower air outlet is connected to a stainless steel pneumatic tube or a non-metallic high-pressure air pipe.

[0061] Preferably, the sand stirring assembly includes a sand stirring blade 407 and a blade bracket 405, the sand stirring blade 407 is connected to the pressure dividing column 403 and / or the rotary sand suction head 408 through the blade bracket 405, and the sand stirring blade 407 is connected to the pressure relief valve 404 through an air pipe.

[0062] The distance between the upper end of the sand stirring blade 407 and the rotary sand suction head 408 is ≤300 mm, ensuring that the stirred underground sand 6 can be sucked into the three-phase mixing column 409.

[0063] Specifically, the sand stirring blade 407 is a three-blade propeller, which is connected to the above-mentioned stainless steel pneumatic tube or non-metallic high-pressure air pipe, driven by the output gas of the pressure relief valve 404, with a working outer diameter ≤75mm and a rotation speed ≤300rpm. When rotating, the outer diameter coverage range of the blade is smaller than the projected area of ​​the sand suction device (to avoid contact with the casing 2 or the filter 5 during rotation).

[0064] The rotary sand suction head 408 is made of brass or stainless steel or above, and is a hollow cylinder with a closed lower end and an open upper end. The upper end is threadedly connected to the three-phase mixing column 409, and a plurality of slits are obliquely opened on the side. Figure 3The angle between the slit and the axis of the three-phase mixing column 409 is ≥60°, the slit width ranges from 0.5mm to 2mm, and the opening length of each slit is ≥2cm. The sand stirring blade 407 stirs up the settled sand 6 and mixes it with the liquid phase, and is sucked into the three-phase mixing column 409 by rotating toward the slit, which can control the proportion of sucked particles and avoid the blockage of the grouting pipe 8 caused by the straight-through opening sand suction, and the particles falling back along the inner wall of the grouting pipe 8 due to insufficient negative pressure of the air lift.

[0065] After multiple tests and verifications, the total area calculation formula of the slit of the rotary sand suction head 408 is:

[0066] S 吸砂头开缝 = π ·d p ·d 三相混合柱内径

[0067] The opening area is controlled within the S calculated by the above formula. 吸砂头开缝 ±5% is appropriate. Tests show that such a design can control the mass ratio of the solid content in the pipe at 10-15%. When the slit area is too large, the flow velocity of the particles through the gap is reduced, and the sand carrying efficiency for medium and large particles (above 1 mm) is reduced by more than 35%; when the slit area is too small, the pressure loss increases sharply, the energy consumption increases (under the same conditions, the liquid-solid mixture lifted to the ground is reduced by 18%-21%), and the stirred up sand is easy to block the rotary sand suction head 408, resulting in a decrease in the sand carrying efficiency.

[0068] As an optional implementation, the three-phase mixing column 409 is made of brass or stainless steel, with an outer diameter of ≤40 mm and a pressure resistance of ≥10 MPa. The top, side and bottom of the column are open and connected to the grouting pipe joint 411, the jet inclined pipe 401 and the rotary sand suction head 408 respectively. Figure 2 A one-way valve plate 410 is installed inside the three-phase mixing column 409 and below the connection between the three-phase mixing column 409 and the injection inclined tube 401. The one-way valve plate 410 opens upward. The one-way valve plate 410 is made of brass or stainless steel and is fitted with the inner wall of the three-phase mixing column 409 in a clearance. It is closed under the action of natural gravity. When the pressure difference between the upper and lower parts of the one-way valve plate 410 exceeds 0.1MPa, the valve plate opens. When the operation is completed or the equipment is shut down unexpectedly, the one-way valve plate 410 automatically closes, and the sand 6 moving upward in the pipe will be separated by the one-way valve plate 410 and will not flow back to the bottom of the well, avoiding the accumulation of secondary sand 6.

[0069] The upper end of the three-phase mixing column 409 is connected to a grouting pipe joint 411, which is made of brass or stainless steel or above. The upper end of the grouting pipe joint 411 is connected to the grouting pipe 8 by threading, and the lower end is welded or threaded to the three-phase mixing column 409. The maximum outer diameter of the grouting pipe joint 411 is ≤50mm, and the pressure resistance is ≥10MPa. During construction, the lowering depth of the device is controlled by the grouting pipe 8 to avoid direct insertion into the sand settling 6 too deep, resulting in poor sand absorption effect.

[0070] Example 2

[0071] A method for negative pressure sand suction in an in-situ uranium leaching well, the method being implemented based on the negative pressure sand suction device in an in-situ uranium leaching well of Example 1, comprising:

[0072] Step S1, according to the downhole TV observation results and the position of the filter 5, the total height of the downhole sand settling 6 is determined, and the initial lowering position of the downhole negative pressure sand suction device for in-situ leaching uranium is calculated, which is usually 0.5-1m above the sand settling 6. At the same time, the static water level data is collected to calculate the static liquid column pressure at the sand suction position.

[0073] Step S2, according to the static liquid column pressure, the pressure setting of the pressure relief valve 404 is adjusted upward by a coefficient of 5%, such as 400 meters of liquid column height, and the critical pressure of the pressure relief valve 404 is adjusted to 4.2 MPa.

[0074] Step S3, connect the grouting pipe joint 411 to the grouting pipe 8 through threads on the ground, and connect the 4 air duct joint 402 to the air duct 3.

[0075] Step S4: Under the operation of drilling or crane, lower the negative pressure sand suction device for in-situ uranium leaching into the well. During the operation, be careful to avoid collision between the device and the inner wall of the casing 2.

[0076] The height of the grouting pipe 8 reserved at the wellhead should be higher than the height of the sand settling 6. The grouting pipe 8 is fixed at the wellhead to prevent the grouting pipe 8 from shaking and knocking against the inner wall of the casing 2 during high-speed transportation inside the pipe; the part of the air duct 3 from the bottom of the well to the ground is a whole piece to ensure that the pressure resistance grade meets the use requirements.

[0077] The outlet of the grouting pipe 8 on the ground is connected to the solid-liquid separation equipment, and the air inlet of the air duct 3 is connected to the air compressor 1.

[0078] By pre-connecting the components on the ground, the air duct 3 is lowered together with the grouting pipe 8 through a drilling rig or a crane, thereby avoiding the problem that the air duct 3 cannot be lowered all at once due to buoyancy when washing wells with a conventional air compressor, and reducing the construction difficulty when washing deep wells.

[0079] Step S5, turn on the air compressor 1, adjust the working pressure to 1.1-1.5 times the adjustment pressure of the pressure relief valve 404 (ensure that the pressure relief valve 404 can drive the pneumatic sand stirring blades), perform sand removal operation, take samples at a fixed frequency, and measure the particle content in the sucked out material. When the particle content is reduced to less than 30% of the initial working condition, suspend sand removal and continue to lower the grouting pipe 8 by 50-100cm. Repeat the operation in this way, and the total lowering depth does not exceed the total height of the sand settling 6.

[0080] Step S6, after the sand 6 is cleaned, turn off the air compressor 1, and then close the one-way valve plate 410. Use a drilling rig or a crane to lift and disassemble the grouting pipe 8 section by section, and collect the sand 6 remaining in the pipe due to the obstruction of the one-way valve plate 410 for processing. The operation is now completed.

[0081] The method of the present application is further explained below through specific implementation cases.

[0082] It is known that the filter 5 of a certain uranium extraction well is located at 592m-600m, the lower end sand settling pipe 7 is 2m long, the sand settling 6 is 8m deep, the static pressure liquid level is 150m from the ground, the maximum boost pressure of the air compressor unit is 6.2MPa, and the liquid density is 1050kg / m 3 , the steps are as follows:

[0083] Step S1, according to the installation reserve of 1m of the downhole negative pressure sand suction device, combined with the static liquid level data, the liquid column height at the sand suction position is calculated as: 600+2-8-150-1=443m, and the static liquid column pressure at the sand suction position is: 1050*9.8*443 / 106M=4.56MPa;

[0084] Step S2, according to the static liquid column pressure at the lowering height of the downhole negative pressure sand suction device, the pressure setting of the pressure relief valve 404 is adjusted upward by a coefficient of 5%, and the critical pressure of the pressure relief valve 404 is adjusted to: 4.56*1.05=4.79MPa.

[0085] Step S3, connect the grouting pipe joint 411 to the grouting pipe 8 through threads on the ground. Connect the air duct joint 402 to the air duct 3.

[0086] Step S4: Under the operation of drilling or crane, the first grouting pipe 8 and the air duct 3 connected to the underground negative pressure sand suction device are lowered into the well. The length of a single grouting pipe 8 is 8m. While lowering, the connected grouting pipes 8 are added. The device is lowered to the specified depth. The height of the grouting pipe 8 reserved at the wellhead is 8m or higher, and the grouting pipe 8 is fixed at the wellhead.

[0087] Step S5, connecting the outlet of the grouting pipe 8 on the ground to the solid-liquid separation equipment, and connecting the air inlet of the air duct 3 to the air compressor 1.

[0088] Turn on the air compressor 1, set the working pressure to 5.27 MPa according to 1.1 times the pressure of the pressure relief valve 404, start the sand removal operation, take samples once an hour, and measure the particle content in the sucked out material. When the particle content is reduced to 30% of the initial working condition, stop running the air compressor 1, and continue to lower the grouting pipe 8 by 1m. Repeat this cycle for a total of seven times. When the particle content is reduced to 30% of the initial working condition for the last time, the sand extraction is completed.

[0089] Step S5, after the height of the sediment 6 is cleaned, turn off the air compressor 1, and at this time, the one-way valve plate 410 is closed. Use a drilling rig or a crane to lift and disassemble the grouting pipe 8 section by section, and collect the sediment 6 remaining in the grouting pipe 8 due to the obstruction of the one-way valve plate 410 for processing. The operation is now completed.

[0090] The present invention uses a grouting pipe 8 to transport sand-carrying liquid, which greatly improves the liquid-solid two-phase flow rate at the wellhead and increases the downhole sand removal efficiency. Taking the conventional 128mm casing 2 and 40mm grouting pipe 8 as examples for comparison, when the same negative pressure air is applied, theoretical calculation: the sand-carrying flow rate of the grouting pipe 8 generated by the present invention is 21 times the sand-carrying flow rate of the casing 2. Excluding factors such as large friction resistance of small pipe diameters, the flow rate can still be more than 10 times. Therefore, in combination with the actual use scenario, on the basis of meeting the boosting capacity, an air compressor 1 with a smaller gas volume can be selected to save energy. Experiments show that in in-situ leaching process wells with similar sand production conditions, the amount of sand carried by using the device of the present invention to absorb sand for 6 hours is equivalent to the amount of sand carried by an air compressor to directly wash the hole for 35 hours.

[0091] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A negative pressure sand suction device for in-situ leaching of uranium, characterized in that: include: An air duct (3) joint, the air duct (3) joint being connected to the end of the air duct (3); A pressure dividing column (403), the pressure dividing column (403) being connected to the lower end of the joint of the air duct (3); A pressure relief valve (404), the pressure relief valve (404) being arranged at the lower end of the pressure dividing column (403); A discharge and injection inclined tube (401), one end of which is connected to a side surface of the pressure dividing column (403); A three-phase mixing column (409), wherein the three-phase mixing column (409) is parallel to the pressure dividing column (403), and the other end of the discharge and injection inclined pipe (401) is connected to the side of the three-phase mixing column (409); A rotary sand suction head (408), the rotary sand suction head (408) is arranged at the lower end of the three-phase mixing column (409), and a plurality of slits are obliquely opened on the side surface; A sand stirring assembly, wherein the sand stirring assembly is connected to the pressure relief valve (404).

2. The negative pressure sand suction device for in-situ leaching of uranium according to claim 1, characterized in that: The included angle between the injection inclined tube (401) and the pressure dividing column (403) is ≤60°, and the outer diameter of the discharge injection inclined tube (401) is ≤40 mm; The angle between the injection inclined tube (401) and the pressure dividing column is calculated based on the inner diameter of the injection inclined tube (401) and the inner diameter of the three-phase mixing column (409).

3. The negative pressure sand suction device for in-situ leaching of uranium according to claim 1, characterized in that: The slit is obliquely opened along the surface of the rotary sand suction head (408).

4. The negative pressure sand suction device for in-situ uranium leaching according to claim 3 is characterized in that: The angle between the slit and the axis of the three-phase mixing column (409) is ≥60°, the width of the slit is 0.5 mm-2 mm, and the length of the slit is ≥2 cm; The total area of ​​the slits of the rotary sand suction head (408) is calculated from the inner diameter of the jet inclined tube (401) and the inner diameter of the three-phase mixing column (409).

5. The negative pressure sand suction device for in-situ leaching of uranium according to claim 1, characterized in that: A one-way valve plate (410) is provided inside the three-phase mixing column (409), and the one-way valve plate (410) is located below the connection between the three-phase mixing column (409) and the discharge and injection inclined pipe (401).

6. The negative pressure sand suction device for in-situ leaching of uranium according to claim 1, characterized in that: The sand stirring assembly comprises a sand stirring blade (407) and a blade bracket (405); the sand stirring blade (407) is connected to the pressure dividing column (403) and / or the rotary sand suction head (408) via the blade bracket (405); and the sand stirring blade (407) is connected to the pressure relief valve (404) via an air pipe (406).

7. The negative pressure sand suction device for in-situ leaching of uranium according to claim 6, characterized in that: The distance between the upper end of the sand stirring blade (407) and the rotary sand suction head (408) is ≤300 mm.

8. The negative pressure sand suction device for in-situ leaching of uranium according to claim 6, characterized in that: The sand stirring blade (407) is a three-blade propeller.

9. The negative pressure sand suction device for in-situ leaching of uranium according to claim 1, characterized in that: The upper end of the three-phase mixing column (409) is connected to a grouting pipe joint (411), the outer diameter of the grouting pipe joint (411) is ≤50 mm, and the outer diameter of the three-phase mixing column (409) is ≤40 mm.

10. A method for negative pressure sand suction in underground uranium leaching, characterized in that: The method is implemented based on the negative pressure sand suction device for in-situ leaching uranium mining according to any one of claims 1 to 9, comprising: According to the downhole television observation results and the position of the filter (5), the total height of the downhole sand settling (6) is determined, and the initial lowering position of the downhole negative pressure sand suction device for in-situ leaching uranium is calculated; static water level data is collected to calculate the static liquid column pressure at the sand suction position; adjusting the working parameters of the pressure relief valve (404) according to the hydrostatic column pressure; According to the initial lowering position, the negative pressure sand suction device for in-situ leaching uranium is lowered into the well and fixed at the wellhead; The sand removal operation is carried out, and samples are taken at a fixed frequency to measure the particle content in the sucked-out material. When the particle content is reduced to less than 30% of the initial working condition, the sand removal is suspended and the lowering is continued for 50-100 cm. The operation is repeated in this way, and the total lowering depth does not exceed the total height of the sand settling (6).

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