A flexible electrode tube for electrically mining rare earths and its usage method

Abstract

The present invention provides a flexible electrode tube for electrically mining rare earth ores and a usage method thereof, which includes a flexible conductive plastic tube, a wire, and a joint area. The flexible conductive plastic tube and the joint area are made of polyethylene, polypropylene, carbon black, and graphite. The outer wall of the flexible conductive plastic tube is smooth, and a spiral wire is embedded in its tube wall. The wire is led out in the joint area and connected to a cable. The joint area is arranged at the top of the flexible conductive plastic tube, and an annular groove is arranged on its outer wall. A clamp is arranged in the groove and connected to a rope for recovering the flexible electrode tube. The usage method of the above flexible electrode tube includes the following steps: S1 opening a liquid injection hole, S2 placing the flexible electrode tube at the bottom of the liquid injection hole, S3 installing a liquid injection tube, S4 connecting the wire-cable to a DC power supply and fixing the rope connecting the clamp, and S5 pulling out the flexible electrode tube by lifting the rope after the mining is completed for repeated use. The present invention has the advantages of good electrical conductivity, corrosion resistance, high strength, easy arrangement, and recovery.

Description

Technical Field

[0001] The present invention relates to the technical field of ionic rare earth mining, and particularly to a flexible electrode tube for electrically mining rare earth and a usage method thereof. Background Art

[0002] Ionic rare earth ores are mainly distributed in South China of our country, rich in high-value medium and heavy rare earth elements, and are important strategic resources of our country. However, the traditional in-situ leaching process with ammonium salts has a long mining cycle and a low rare earth recovery rate, resulting in resource waste. More seriously, this process causes serious ammonia nitrogen pollution to the mining area and surrounding water bodies, and a large amount of manpower and financial resources are required for treatment. In view of this, the newly approved rare earth mining licenses have prohibited the use of this process, and the original ionic rare earth mines have generally stopped production for rectification. Therefore, it is of great significance to develop a new green and efficient ionic rare earth mining process.

[0003] CN109402417A proposes a method for electrically mining rare earth ores, which mainly includes inserting an anode injection tube and a cathode liquid collection tube into the rare earth mine body respectively; using the anode injection tube and the cathode liquid collection tube as two poles to pass direct current, accelerating the migration of the leaching solution, so as to shorten the mining time, improve the mining efficiency, and reduce environmental pollution and geological disasters. This process has good application prospects.

[0004] As the core materials for electrically mining rare earth, the anode injection tube and the cathode liquid collection tube largely determine the mining cost and efficiency of the system. A conductive plastic drainage board (CN102720182A) and a plastic electrode tube for electroosmotic drainage method (CN104088272A) overcome the defects of easy corrosion and easy fusing of traditional metal electrodes and have been widely used in drainage consolidation.

[0005] However, the above electrodes are not efficient when directly used for electrically mining rare earth. More importantly, it is difficult to meet the requirements of electrode recovery and reuse, resulting in high mining costs. Therefore, it is necessary to further optimize the electrode material formula to achieve the organic unity of conductivity, corrosion resistance and material strength, and improve the mining efficiency; in addition, it is also necessary to optimize its layout method so that it can be taken out intact from the injection hole after mining and reused to reduce the mining cost. Summary of the Invention

[0006] The purpose of the present invention is to solve the defects existing in the above-mentioned prior art, and provide a flexible electrode tube for electrically mining rare earth ores and a usage method thereof, which have good conductivity, corrosion resistance, tensile strength and other properties, and optimize its layout method, so as to reduce the cost while improving the mining efficiency.

[0007] The present invention adopts the following technical solutions:

[0008] A flexible electrode tube for electrified rare earth ore mining. The flexible electrode tube includes a flexible conductive plastic tube, a wire, and a joint area. The top of the flexible conductive plastic tube is integrally formed with the joint area. The joint area has a plurality of annular grooves. The wire has a very high electrical conductivity and is spirally embedded in the wall of the flexible conductive plastic tube, evenly distributed from top to bottom. Therefore, the wire can uniformly and effectively transmit current to the entire tube wall, greatly shortening the transmission distance of the current in the high-resistance flexible conductive plastic tube and effectively reducing the overall resistance of the flexible electrode tube.

[0009] Note: The wire has a low resistance, and the flexible conductive plastic tube has a high resistance. The current mainly passes through the wire. Since the wire is evenly spirally embedded in the flexible conductive plastic tube, it can ensure that the flexible conductive plastic tube near the wire has a uniform current flowing through. Compared with directly using a flexible conductive plastic tube with a high resistance, the transmission distance of the current in it is shortened. Therefore, compared with a flexible electrode tube without an embedded wire, the overall resistance of the flexible electrode tube is reduced.

[0010] Preferably, during mining, the wire is connected to a waterproof snap joint through a cable. The waterproof snap joint is connected to an n-to-1 connector. The n-to-1 connector is connected to a DC power supply through a cable. Part of the flexible electrode tubes are connected to the positive pole of the DC power supply, and part of the flexible electrode tubes are connected to the negative pole of the DC power supply, and the number of those connected to the positive pole is equal to the number of those connected to the negative pole.

[0011] Preferably, the bottom of the flexible conductive plastic tube is open, the outer wall is smooth, and the wire is a single metal wire.

[0012] Preferably, the outer diameter of the flexible conductive plastic tube is 40 - 80 mm, the wall thickness is 2 - 4 mm, and the tube length is 3 - 21 m.

[0013] Preferably, the flexible conductive plastic tube is made of polyethylene, polypropylene, carbon black, and graphite, with a mass ratio of 1:0.1 - 0.2:0.4 - 0.5:0.1 - 0.2, and the resistivity is lower than 10 -3 Ω·m.

[0014] Preferably, the wire is copper wire or aluminum wire, and the cross-sectional area is 0.78 - 6 mm 2 .

[0015] Preferably, the pitch of the spiral wire embedded in the flexible conductive plastic tube is 30 - 80 mm.

[0016] Preferably, the joint area is made of polyethylene, polypropylene, carbon black, and graphite, with a mass ratio of 1:0.4 - 0.6:0.4 - 0.5:0.1 - 0.2, and the resistivity is lower than 5×10 -3 Ω·m.

[0017] Preferably, the length of the joint area is 0.2 - 0.5 m, the outer diameter is 30 - 70 mm, the wall thickness is 10 - 20 mm, and 2 - 5 annular grooves are arranged on the outer wall, with the groove depth and width being 4 - 15 mm and 20 - 40 mm respectively.

[0018] Preferably, the groove is also provided with a clamp, and a rope for pulling is fixed on the clamp.

[0019] Preferably, after the wire is led out from the top of the flexible conductive plastic pipe, it is connected to the cable, and the waterproofing of the exposed part of the wire and the joint is done well.

[0020] Preferably, the flexible electrode tube can be wound up on a winder for convenient transportation.

[0021] Preferably, the flexible electrode tube is arranged in the ore body layer, and the overlying surface soil layer is not arranged.

[0022] A method for using a flexible electrode tube for electrically mining rare earth ores includes the following steps:

[0023] Step 1. Injection holes are arranged in the mining area, with the hole diameter being 40 - 80 mm, and the bottom of the hole being 1 - 2 m higher than the bottom of the rare earth ore body. This height difference not only ensures the uniform distribution of the leaching agent but also enhances the promotion effect of the electric field on the migration of rare earth.

[0024] Step 2. Slowly insert the flexible electrode tube to the bottom of the injection hole, with its top end located at the interface between the rare earth ore body layer and the surface soil layer.

[0025] Step 3. Insert the injection tube (with a diameter of 10 - 20 mm) into the injection hole, with the length being exactly inserted into the joint area of the flexible electrode tube. The injection tube is mainly used to inject the leaching solution into the flexible electrode tube.

[0026] Step 4. Fix the rope connected to the clamp on the ground column, insert the waterproof snap connectors of n cables into an n - to - 1 waterproof connector (where 1 < n < 10), transfer to the main cable and then connect to the corresponding positive or negative pole of the DC power supply, and carry out the electric mining of rare earth according to the corresponding process.

[0027] Step 5. After mining, pull out the flexible electrode tube cable from the n - to - 1 waterproof connector, pull out the injection tube, and then lift the rope to pull out the flexible electrode tube from the injection hole for future use.

[0028] The beneficial effects of the present invention:

[0029] (1) Achieved the unity of electrical conductivity, corrosion resistance, and tensile strength

[0030] The flexible electrode tube is made of polyethylene, polypropylene, carbon black, and graphite. Polypropylene can improve the tensile strength of the material, while polyethylene can improve the aging resistance and flexibility of the material. Carbon black and graphite can improve the conductivity of the material. The spiral wire embedded in the flexible conductive plastic tube can efficiently transmit current evenly throughout the electrode tube, reducing energy consumption and improving the efficiency of rare earth extraction by electrification.

[0031] (2) Simple layout, easy to reuse, and the materials are light and easy to transport

[0032] The outer wall of the flexible electrode tube provided by the present invention is smooth and includes a joint area. An annular groove is provided on the outer wall of the joint area, and a clamp is provided on the groove. A rope for pulling is fixed on the clamp. After the electric mining is completed, the flexible electrode tube can be pulled out from the liquid injection hole by lifting the rope to achieve repeated use. At the same time, the hardness of the flexible electrode tube is between that of a flexible hose and a rigid tube, and it can be wound on a winding machine for convenient transportation. In addition, for the flexible electrode tube provided by the present invention, the cables connected to the wires are all provided with simple sockets, and can be conveniently connected to the main cable and the DC power supply through an n-to-1 adapter. Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the flexible electrode tube;

[0034] Figure 2 It is a schematic diagram of the layout method of the flexible electrode tube.

[0035] In the figure: 1 - flexible electrode tube; 2 - flexible conductive plastic tube; 3 - wire; 4 - joint area; 5 - groove; 6 - cable; 7 - waterproof snap joint; 8 - rope; 9 - liquid injection tube; 10 - liquid injection hole; 11 - surface soil layer; 12 - clamp; 13 - ore body layer. Detailed Embodiments

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0037] Such as Figure 1-2As shown in the figure, a flexible electrode tube for electrified mining of rare earth ores according to the present invention, the flexible electrode tube 1 includes a flexible conductive plastic tube 2, a wire 3 and a joint area 4. The upper part of the flexible conductive plastic tube 2 is integrally formed with the joint area 4. The wire 3 is spirally embedded in the tube wall of the flexible conductive plastic tube 2. The wire 3 is made of aluminum wire or copper wire, and both of these two materials have excellent electrical conductivity. The wire 3 is used to uniformly transmit current to the entire flexible conductive plastic tube 2. Compared with the flexible conductive plastic tube without an embedded wire, the transmission distance of the current in the plastic conductive material is effectively reduced (only the lead of the wire 3), thereby reducing the resistance. The wire 3 is connected to a waterproof snap joint 7 through a cable 6 to ensure the waterproof performance of the connection. The waterproof snap joint 7 is then connected to an n-to-1 connector, and the n-to-1 connector is connected to a DC power supply through a cable to form a stable current transmission system. Some flexible electrode tubes are connected to the positive pole of the DC power supply, and some flexible electrode tubes are connected to the negative pole of the DC power supply, and the numbers of both are equal.

[0038] Furthermore, both the flexible conductive plastic tube 2 and the joint area 4 are made of polyethylene, polypropylene, carbon black and graphite.

[0039] Furthermore, the bottom of the flexible conductive plastic tube 2 is open and the outer wall is smooth.

[0040] Furthermore, the joint area 4 has a plurality of annular grooves 5, and the grooves are provided with clamps 12.

[0041] A method for using a flexible electrode tube for electrified mining of rare earth ores according to the present invention includes the steps:

[0042] ① Open the liquid injection hole 10; ② Insert the flexible electrode tube 1 to the bottom of the liquid injection hole 10, and install the clamp 12 into the annular groove of the joint area 4; ③ Install a liquid injection tube 9 at the orifice of the liquid injection hole 10 and inject the leaching solution; ④ Connect the cable 6 led out from the flexible electrode tube 1 to a DC power supply through a waterproof snap joint and an adapter, and fix the rope connecting the clamp 12 to a ground column to electrifiedly mine rare earth; ⑤ After the mining is completed, unplug the cable 6 of the flexible electrode tube 1 from the n-to-1 waterproof connector, pull out the liquid injection tube 9, and pull out the flexible electrode tube 1 from the liquid injection hole 10 by lifting the rope.

[0043] Example 1

[0044] This embodiment provides a flexible electrode tube for electrically mining rare earth ores. The test mining area is 90.72 square meters, with a length of 12.6 meters and a width of 7.2 meters. Based on the exploration results, the topsoil layer is 6 meters thick, the ore body thickness is 10.5 meters, the average grade of ion-adsorbed rare earth is about 500 ppm, and the total content is about 0.74 tons. Among them, the flexible conductive plastic tube 2 and the joint area 4 are made of raw materials in the following mass ratio: the mass ratio of polyethylene, polypropylene, carbon black, and graphite is 1:0.15:0.45:0.15, and its resistivity is 8.8×10 -4 Ω·m.

[0045] As Figure 1 shown, the length of the flexible conductive plastic tube 2 is 9m, the length of the joint area 4 is 0.3m, the outer diameter of the flexible conductive plastic tube 2 is 50mm, the wall thickness is 3mm, the outer diameter of the joint area 4 is 40mm, and the wall thickness is 12mm; among them, 3 annular grooves 5 are arranged in the joint area 4, and their depth and width are 6mm and 30mm respectively.

[0046] A spiral wire 3 is embedded in the wall of the flexible conductive plastic tube 2, and its lead is 50mm; the wire 3 is made of aluminum wire, and the cross-sectional area is 1.5mm; the wire 3 is connected to the cable 6 through an aluminum-copper conversion joint. The cable 6 is a 1.5-square ZC-BVVR copper core cable, and a waterproof snap joint 7 is installed at the end of the cable 6.

[0047] A method for using a flexible electrode tube for electrically mining rare earth ores includes the following steps:

[0048] Step 1. Manually drill liquid injection holes 10 in the rare earth ore mining area, with a hole diameter of 50mm, a hole depth of 15.3m, the bottom of the liquid injection hole is 1.2m away from the bottom of the ore body layer 13, there are 8 rows and 5 columns of liquid injection holes, and the spacing is 1.8m;

[0049] Step 2. Fix 2 clamps 12 on the grooves 5 of the joint area 4 respectively, and string 2 ropes 8 through the two ends of the 2 clamps 12 respectively to make the force evenly distributed during lifting. The length of the rope 8 is 7m; slowly lower the flexible electrode tube 1 to the bottom of the liquid injection hole 10;

[0050] Step 3. Insert a liquid injection tube 9 with a diameter of 10mm into the liquid injection hole. The length of the liquid injection tube 9 is 6.3m and it just inserts into the joint area 4;

[0051] Step 4. Fix the rope 8 on the column near the liquid injection hole 10; insert the waterproof snap joint 7 of the cable 6 into a 5-in-1 waterproof connector, connect it to the flexible electrode tubes 1 of the other 4 liquid injection holes together, and then connect it to the main cable through the waterproof snap joint 7, and finally connect the main cable to the corresponding positive or negative pole of the DC power supply;

[0052] Step 5. Mine rare earths according to the corresponding process. A total of 0.68 tons of rare earths were collected in 45 days, with a recovery rate of 92% and a total power consumption of 2200 kW·h.

[0053] Step 6. After the mining is completed, unplug each cable from the 5-in-1 waterproof connector and pull out the liquid injection pipe 9; evenly lift the two ropes 8 and slowly pull out the flexible electrode tube from the liquid injection hole 10 for reuse next time.

[0054] Example 2

[0055] This example provides a flexible electrode tube for mining rare earth ore by electrification. The test mining area is 129.6 square meters, with a length and width of 14.4 meters and 9 meters respectively. Based on the exploration results, the overburden layer is 5 meters, the ore body thickness is 7 meters, the average grade of ion-adsorbed rare earth is about 600 ppm, and the total content is about 0.82 tons. Among them, the flexible conductive plastic tube 2 and the joint area are made of raw materials in the following mass ratio: the mass ratio of polyethylene, polypropylene, carbon black and graphite is 1:0.1:0.4:0.1, and its resistivity is 9.2×10 -4 Ω·m.

[0056] As Figure 1 shown, the total length of the flexible electrode tube 1 is 6.2 m, of which the length of the flexible conductive plastic tube 2 is 6 m, and the length of the joint area 4 is 0.2 m. The outer diameter of the flexible conductive plastic tube 2 is 45 mm, and the wall thickness is 3 mm. The outer diameter of the joint area 4 is 35 mm, and the wall thickness is 10 mm; among them, two annular grooves 5 are provided in the joint area 4, and their depth and width are 5 mm and 30 mm respectively.

[0057] A spiral wire 3 is embedded in the wall of the flexible conductive plastic tube 2, and its lead is 45 mm; the material of the wire 3 is copper wire, and the cross-sectional area is 1 mm 2 ; the cable 6 connected to the wire 3 is 1.5 mm 2 ZC-BVVR copper core cable, and a waterproof snap joint 7 is installed at the end of the cable.

[0058] A layout method for a flexible electrode tube for mining rare earth ore by electrification includes the following steps:

[0059] Step 1. Manually drill liquid injection holes 10 in the rare earth ore mining area, with a hole diameter of 45 mm and a hole depth of 11.2 m; the spacing of the liquid injection holes 10 is 1.8 m, and the total number is 54.

[0060] Step 2. Fix two clamps 12 on the grooves 5 of the joint area 4 respectively, and connect the two ropes 8 to the two ends of the two clamps 12 respectively to ensure uniform force during lifting. The length of the rope 8 is 7 m; slowly put the flexible electrode tube 1 to the bottom of the liquid injection hole 10.

[0061] Step 3. Insert the liquid injection tube 9 with a diameter of 10 mm into the liquid injection hole. The length of the liquid injection tube 9 is 5.3 m, which is just inserted into the joint area 4;

[0062] Step 4. Fix the rope 8 on the column near the liquid injection hole 10; Insert the waterproof snap joint 7 of the cable 6 into the 6-in-1 waterproof connector. After connecting the flexible electrode tubes 1 of the other 5 liquid injection holes to the 6-in-1 waterproof connector together, then connect them to the main cable through the waterproof snap joint 7, and finally connect the main cable to the corresponding positive or negative pole of the DC power supply;

[0063] Step 5. Mine rare earth according to the corresponding process. A total of 0.77 tons of rare earth were collected in 40 days, the recovery rate was 94%, and the total power consumption was 2350 kW·h.

[0064] Step 6. After the mining is completed, pull out each cable from the 6-in-1 waterproof connector and pull out the liquid injection tube 9; Lift the 2 ropes 8 evenly and slowly pull out the flexible electrode tube from the liquid injection hole 10 for reuse next time.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 1 is the different electrode tubes used; In this comparative example, the flexible electrode tube 1 is replaced with a common conductive plastic tube, and its resistivity is 1.2×10 -3 Ω·m, and it does not include recovery devices such as joint areas.

[0067] This comparative example mined rare earth according to the same process as Example 1. A total of 0.63 tons of rare earth were collected in 50 days, the recovery rate was 85%, and the total power consumption was 2580 kW·h. Compared with Example 1, the common conductive plastic tube used in this example has a relatively high resistivity, which results in higher energy consumption and lower recovery rate.

[0068] After the mining is completed, the conductive plastic tube 2 is difficult to be pulled out from the liquid injection hole 10 and cannot be reused.

[0069] Comparative Example 2

[0070] The difference between this comparative example and Example 2 is the different electrode tubes used; In this comparative example, the flexible electrode tube 1 is replaced with a common conductive plastic tube, and its resistivity is 1.3×10 -3 Ω·m, and it does not include recovery devices such as joint areas.

[0071] This comparative example mined rare earth according to the same process as Example 2. A total of 0.72 tons of rare earth were collected in 44 days, the recovery rate was 88%, and the total power consumption was 2730 kW·h. Compared with Example 2, the common conductive plastic tube used in this example has a relatively high resistivity, which results in higher energy consumption and lower recovery rate.

[0072] After the mining is completed, it is difficult to pull out the conductive plastic tube 2 from the liquid injection hole 10, and it cannot be reused.

[0073] It can be seen from the above embodiments that the flexible electrode tube and its arrangement method provided by the embodiments of the present invention not only have high rare earth mining efficiency and low energy consumption, but also the electrode tube can be recycled and reused, greatly reducing the mining cost. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended 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 of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for using a flexible electrode tube for mining rare earth by electricity, characterized in that: The flexible electrode tube adopted includes a flexible conductive plastic tube, a wire, and a joint area. The flexible conductive plastic tube is integrally formed with the joint area. The joint area has a plurality of annular grooves. The wire has a high resistivity. The wire is spirally embedded in the wall of the flexible conductive plastic tube and is evenly arranged from top to bottom, enabling the wire to uniformly and effectively transmit current to the entire tube wall, shortening the transmission distance of the current in the high-resistance flexible conductive plastic tube, and reducing the overall resistance of the flexible electrode tube. The bottom of the flexible conductive plastic tube is open and the outer wall is smooth. The wire is a single metal wire. The outer diameter of the flexible conductive plastic tube is 40 - 80 mm, the wall thickness is 2 - 4 mm, and the tube length is 3 - 21 m. The usage method is as follows: Step 1. Arrange injection holes in the mining area. The aperture of the injection holes is 40 - 80 mm, and the bottom of the holes is 1 - 2 m higher than the bottom of the rare earth ore body. Step 2. Slowly place the flexible electrode tube at the bottom of the injection hole, and its top end is located at the interface between the rare earth ore body layer and the topsoil layer. Step 3. Insert the injection tube into the injection hole, and the length is just inserted into the joint area of the flexible electrode tube. The injection tube is mainly used to inject leaching solution into the flexible electrode tube. Step 4. Fix the rope with a connecting clamp on the ground column, and insert the waterproof snap connectors of n cables into the n - to - 1 waterproof connector. Among them, 1 < n < 10. After transferring to the main cable, connect it to the corresponding positive or negative pole of the DC power supply, and carry out rare earth mining according to the corresponding process. Step 5. After mining, pull out the flexible electrode tube cable from the n - to - 1 waterproof connector, and pull out the injection tube. Then lift the rope to pull out the flexible electrode tube from the injection hole for future use.

2. The method according to claim 1, characterized in that During mining, the wire is connected to the waterproof snap connector through a cable. The waterproof snap connector is connected to the n - to - 1 connector. The n - to - 1 connector is connected to the DC power supply through a cable. Some flexible electrode tubes are connected to the positive pole of the DC power supply, and some flexible electrode tubes are connected to the negative pole of the DC power supply, and the number of those connected to the positive pole is equal to the number of those connected to the negative pole.

3. The method according to claim 1, characterized in that The flexible conductive plastic tube is made of polyethylene, polypropylene, carbon black and graphite in a mass ratio of 1:0.1-0.2:0.4-0.5:0.1-0.2, and has a resistivity of less than 10 -3 Ω·m.

4. The method according to claim 1, characterized in that: The conductor is a copper wire or an aluminum wire with a cross-sectional area of ​​0.78-6mm 2 .

5. The method according to claim 1, characterized in that The lead of the spiral wire embedded in the flexible conductive plastic tube is 30 - 80 mm.

6. The method according to claim 1, characterized in that The joint area is made of polyethylene, polypropylene, carbon black and graphite, with a mass ratio of 1:0.4-0.6:0.4-0.5:0.1-0.2, and the resistivity is less than 5×10 -3 Ω·m.

7. The method according to claim 1, characterized in that The length of the joint area is 0.2 - 0.5 m, the outer diameter is 30 - 70 mm, the wall thickness is 10 - 20 mm, and 2 - 5 annular grooves are provided on the outer wall. The depth and width of the grooves are 4 - 15 mm and 20 - 40 mm respectively.

8. The method according to claim 1, characterized in that: The groove also has a clamp, and a rope for pulling is fixed on the clamp.

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