A method for in-situ leaching of rare earth ore based on microwave heating

Abstract

The present invention belongs to the technical field of solution mining, and discloses an ionic rare earth in-situ leaching mining method based on microwave heating, comprising: creating a mesh well, arranging an infrared thermal imager in a monitoring well; arranging a liquid collecting pipeline below a rare earth ore layer; injecting leaching solution into the ground and heating it with the aid of microwaves; the leaching solution continuously exchanges rare earth ions from the top of the ore bed downward, and when it flows to a corresponding depth, the temperature there rises, and the infrared thermal imager probe and computer are used to form a map, and the monitoring data is processed by a computer to obtain a temperature cloud map of each part of the ore bed; the seepage range and flow direction of the leaching solution are judged according to the expansion direction of the temperature rising area in the temperature cloud map, and the area not impregnated by the leaching solution is found according to the low temperature area, and an injection well is added near it, and finally the leaching solution is collected. The present invention solves the problem that the seepage range and leakage position of the leaching solution cannot be confirmed during the ionic rare earth in-situ leaching mining process, and is suitable for ionic rare earth mining.

Description

Technical Field

[0001] The invention relates to the technical field of solution leaching mining, and in particular to an ionic rare earth in-situ leaching mining method based on microwave heating. Background Art

[0002] Rare earth is a general term for 17 rare earth elements, which are widely distributed in China, Mongolia, Russia, the United States, Australia and other countries. Since its discovery, it has been widely used in military, petrochemical, metallurgical industries and other fields, and has earned the reputation of "industrial vitamins". The known reserves of heavy rare earth on the earth are almost concentrated in China, which is an important strategic resource for my country. Among them, ionic rare earth is almost unique to my country, so it is of great significance to extract ionic rare earth ores with high efficiency.

[0003] Ionic rare earth in-situ leaching is developed based on in-situ leaching technology. Its main leaching solution is ammonium sulfate. The mining process uses technologies such as net well static pressure injection to inject the leaching solution into the ore layer, replace the rare earth elements adsorbed in the ore layer, and collect the ore solution at the foot of the mountain. The advantage of this method is that there is no expensive and heavy basic engineering, which not only reduces the cost of rock and mineral crushing and transportation, but also does not damage fields and forests, thereby protecting the ecological environment.

[0004] However, the in-situ leaching mining process of ionic rare earths also has the following problems: on the one hand, during the injection of the leaching solution, the leaching solution cannot reach the entire ore body due to factors such as permeability, osmotic pressure, and injection well layout, forming a leaching "blind spot" and causing leaching losses; on the other hand, there is the loss of leaching mother liquor recovery. The leaching mother liquor leaks along the cracks in the ore layer during the seepage process, resulting in the inability to fully recover the mother liquor and causing losses. Summary of the invention

[0005] The present invention aims to provide an ionic rare earth in-situ leaching mining method based on microwave heating to solve the problem that the seepage range and leakage position of the leaching solution cannot be confirmed during the ionic rare earth in-situ leaching mining process.

[0006] In order to achieve the above object, the present invention provides the following technical solution: an ionic rare earth in-situ leaching mining method based on microwave heating, comprising the following steps:

[0007] S1. Build a network of wells according to the size, location and burial depth of the underground ore body. The network of wells includes three types: injection wells, composite wells and monitoring wells. The composite well consists of an injection well and a microwave transmission pipeline wrapped outside the injection well. A microwave receiving device is set in the microwave transmission pipeline.

[0008] S2. Infrared thermal imagers are evenly arranged in the monitoring wells. The arrangement range is between the layers of the rare earth deposits. The infrared thermal imagers use wide-angle lenses with a field of view of 90° to 120°. Infrared thermal imagers are evenly installed from the bottom of the monitoring wells according to monitoring needs. The monitoring wells use bottom-closed sleeves made of infrared-transmitting polymer materials.

[0009] S3. Arrange a liquid collecting pipeline on the upper part of the bedrock below the rare earth ore layer, and connect the liquid collecting pipeline to a liquid collector outside the mountain;

[0010] S4. After the arrangement of the injection well, monitoring well, composite well and liquid collecting pipeline is completed, the leaching liquid in the liquid supply pool is injected into the ground through the injection well and the composite well; at the same time, a microwave generator is used to generate beam microwaves, which are transmitted to the microwave receiving device in the composite well along the microwave transmission pipeline; the microwave receiving device converts the received beam microwaves into microwaves that are scattered in a spherical shape with the microwave receiving device as the center, and continuously heats the leaching liquid to keep it at the corresponding temperature;

[0011] S5. The leaching solution continuously exchanges rare earth ions from the top of the ore bed downwards. When it flows to the corresponding depth, the temperature there rises. The infrared thermal imaging probe and computer are used to form a map, and the monitoring data is processed by computer to obtain the temperature cloud map of each part of the ore bed;

[0012] S6. Determine the seepage range and flow direction of the leaching solution according to the expansion direction of the temperature rising area in the temperature cloud map, find out the area not impregnated by the leaching solution according to the low temperature area, and make the uncovered area impregnated by the leaching solution by increasing the leaching solution in the nearby injection wells or increasing the number of nearby injection wells;

[0013] S7. Collect the leaching solution for leaching rare earth ions through the liquid collecting pipe at the bottom of the ore bed.

[0014] Furthermore, in step S1, the drilling depth of the injection well is 2-5 meters deeper than the top surface of the rare earth deposit, and the total depth is 3-6 meters; the composite well is drilled to the middle of the ore layer, and the monitoring well needs to penetrate the rare earth deposit, and the depth of the monitoring well is 0.5 to 1 meter deeper than the bottom of the rare earth deposit.

[0015] Through the above arrangement, the injection efficiency and microwave heating range are ensured, and the problem of rare earth deposits not being penetrated and the increase in economic costs caused by the increase in drilling depth is prevented.

[0016] Furthermore, in step S6, when a discontinuity appears in the extension direction of the temperature rising area or a low temperature area suddenly appears, there are cracks there, and the cracks are sealed by grouting or caulking.

[0017] Through the above arrangement, the usage of leaching solution can be reduced, thereby saving costs.

[0018] Furthermore, the composite wells are arranged at intervals of 10-20 meters, the monitoring wells are evenly inserted into the composite well network, the monitoring distance is 10-20 meters, the monitoring wells are spaced 5-10 meters from the composite wells, and the composite wells and the monitoring wells are arranged alternately.

[0019] Through the above settings, a high injection efficiency and a comprehensive monitoring range are maintained at the same time.

[0020] Furthermore, the heating temperature of the leaching solution ranges from 40°C to 80°C.

[0021] Through the above settings, during the heating process, the farther away from the microwave heating source, the lower the heating temperature, and the closer it is, the higher the heating temperature. The normal temperature is 25 degrees, and the lower limit temperature of 40°C is selected to make it significantly higher than the normal temperature underground, so that the infrared thermal imager can effectively monitor the specific flow direction of the leaching solution. The upper limit temperature is selected to be 80°C because appropriately increasing the temperature can increase ion exchange, thereby increasing the leaching degree of rare earths. When the temperature is too high, it may affect the leaching solution and the local rock and soil properties.

[0022] Furthermore, the microwave heating frequency adopts the industrial microwave frequency of 915 MHz to 2450 MHz.

[0023] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0024] 1. This solution solves the engineering problem of being unable to confirm the seepage range of the leaching solution during the in-situ leaching of ionic rare earths, and promptly discovers the blind areas of leaching.

[0025] 2. This solution solves the engineering problem of being unable to confirm the location of leaching solution leakage during the in-situ leaching mining of ionic rare earths, and promptly discovers the stratum fissures that cause leaching solution leakage.

[0026] 3. In the case of in-situ leaching of ionic rare earths in this scheme, the leaching rate of rare earth ore is low and the leaching time is long. This scheme can also increase the temperature of the leaching solution, increase the leaching rate of rare earths and reduce the leaching time of rare earths. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a front view of an ionic rare earth in-situ leaching mining method based on microwave heating according to the present invention;

[0028] Figure 2 This is a partial enlarged view of the monitoring well.

[0029] The names of the corresponding marks in the accompanying drawings are: monitoring well 1, injection well 2, composite well 3, liquid collector 4, liquid collecting pipeline 5, rare earth deposit 6, bedrock 7, liquid infusion pipe 8, liquid supply tank 9, microwave generating device 10, microwave transmission pipeline 11, infrared thermal imager 12, computer 13, microwave heating range 14, infrared thermal imaging device monitoring area 15, crack 16, microwave receiving device 17, sleeve 18. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0031] like Figure 1 and 2 As shown, a method for in-situ leaching of ionic rare earth ore based on microwave heating comprises the following steps:

[0032] S1. A network of wells is built according to the scale, location and burial depth of the underground ore body, which includes three types: injection well 2, composite well 3 and monitoring well 1. In order to take into account both injection efficiency and microwave heating range 14, the drilling depth of injection well 2 can be 2-5 meters deeper than the top surface of rare earth deposit 6, and the total depth is about 3-6 meters. Composite well 3 is composed of injection well 2 and microwave transmission pipeline 11 wrapped outside injection well 2. Microwave receiving device 17 is arranged in microwave transmission pipeline 11. The number of composite wells 3 is determined according to the microwave action range converted by microwave generating device 10 received by microwave receiving device 17. Composite well 3 is drilled to the middle of the ore layer, and the composite well 3 is arranged at an interval of 10-20 meters. Monitoring well 1 is evenly inserted into the composite well 3 network with a monitoring distance of 10-20 meters. Monitoring well 1 and composite well 3 are separated by 5-10 meters, and composite well 3 and monitoring well 1 are arranged alternately. To monitor the entire ore deposit, the monitoring well 1 needs to penetrate the rare earth ore deposit 6. To prevent the rare earth ore deposit 6 from not being penetrated and to reduce the increase in economic costs due to the increase in drilling depth, the depth of the monitoring well 1 only needs to be 0.5 to 1 meter deeper than the bottom of the rare earth ore deposit 6.

[0033] S2. The infrared thermal imagers 12 are evenly arranged in the monitoring well 1. The monitoring well 1 uses a bottom-sealed sleeve 18 made of infrared-penetrating polymer material to prevent water seepage and reinforce the well wall, while avoiding the influence of the sleeve 18 on the imager. The arrangement range is between 6 layers of the rare earth deposit. The infrared thermal imager 12 uses a wide-angle lens with a field of view of 90° to 120°, which can improve the accuracy of the infrared thermal imager 12 and reduce the number of infrared thermal imagers 12. In this embodiment, the diameter of the monitoring well 1 is about 30 cm, and the range of each monitoring detector is set at 2-4 meters (the infrared thermal imaging device monitors the area 15 such as Figure 2 as shown).

[0034] S3. Liquid collecting pipes 5 are arranged on the upper part of the bottom bedrock 7 below the rare earth ore layer. The number and distribution spacing of the liquid collecting pipes 5 can be determined according to the objective requirements of the ore body. The collecting pipes are connected to the liquid collector 4 outside the mountain.

[0035] S4. After the arrangement of the injection well 2, the monitoring well 1, the composite well 3 and the liquid collecting pipeline 5 is completed, the leaching liquid in the liquid supply pool 9 is injected into the ground from the injection well 2 and the composite well 3 through the liquid delivery pipe 8, and the microwave generator 10 is used to generate beam microwaves, which are transmitted to the microwave receiving device 17 in the composite well 3 along the microwave transmission pipeline 11. The microwave receiving device 17 converts the received beam microwaves into microwaves that are scattered spherically with the microwave receiving device 17 as the center, and continuously heats the leaching liquid to keep it at the corresponding temperature. The microwave heating frequency adopts the industrial microwave frequency of 915MHz to 2450MHz, and the heating temperature range of the leaching liquid is 40℃ to 80℃, so that it is kept at the corresponding temperature. During the heating process, the heating temperature is lower at a distance from the microwave heating source, and higher at a closer distance. The normal temperature is 25 degrees, and the lower limit temperature of 40℃ is selected to make it significantly higher than the normal temperature underground, so that the infrared thermal imager 12 can effectively monitor the specific flow direction of the leaching liquid. The upper limit temperature is selected as 80°C because appropriately increasing the temperature can improve ion exchange, thereby increasing the rare earth leaching degree. When the temperature is too high, it may affect the leaching solution and local rock and soil properties.

[0036] S5. The leaching solution continuously exchanges rare earth ions from the top of the ore bed downwards. When it flows to the corresponding depth, the temperature there rises. The infrared thermal imaging probe and the computer 13 set on the surface are used to form a map, so that the seepage process of the leaching solution can be monitored in real time. The computer 13 is used to process the monitoring data to obtain the temperature cloud map of each part of the ore bed. The flow direction of the leaching solution is determined based on the expansion direction of the heated part in the temperature cloud map.

[0037] S6. Determine the seepage range and flow direction of the leaching solution according to the extension direction of the temperature rising area in the temperature cloud map, find out the area not impregnated by the leaching solution according to the low temperature area, and make the uncovered area impregnated by the leaching solution by increasing the leaching solution in the nearby injection wells 2 or increasing the number of nearby injection wells 2. When there is a discontinuity in the extension direction of the temperature rising area or a large low temperature area suddenly appears, it can be determined that there is a crack 16 here. At this time, grouting and caulking should be used to seal the crack 16 to reduce losses.

[0038] S7. Collect the leaching solution for leaching rare earth ions through the liquid collecting pipe 5 and the liquid collecting container 4 at the bottom of the ore bed.

[0039] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for in-situ leaching of ionic rare earth ores based on microwave heating, characterized in that: The steps include: S1. A network of wells is constructed according to the size, location and burial depth of the underground ore body. The network of wells includes three types: an injection well (2), a composite well (3) and a monitoring well (1). The composite well (3) is composed of an injection well (2) and a microwave transmission pipeline (11) wrapped around the injection well (2). A microwave receiving device (17) is arranged in the microwave transmission pipeline (11); S2. The infrared thermal imagers (12) are evenly arranged in the monitoring well (1), and the arrangement range is between the layers of the rare earth deposit (6). The infrared thermal imagers (12) use wide-angle lenses with a field of view of 90° to 120°. The infrared thermal imagers (12) are evenly installed from the bottom of the monitoring well (1) according to monitoring needs. The monitoring well (1) uses a sleeve (18) with a closed bottom, and the sleeve (18) is made of an infrared penetrating polymer material; S3, arranging a liquid collecting pipeline (5) on the upper part of the bottom bedrock (7) below the rare earth mineral layer, wherein the liquid collecting pipeline (5) is connected to a liquid collecting device (4) outside the mountain; S4. After the arrangement of the injection well (2), the monitoring well (1), the composite well (3) and the liquid collecting pipeline (5) is completed, the leaching liquid in the liquid supply pool (9) is injected into the ground through the injection well (2) and the composite well (3); at the same time, a microwave generating device (10) is used to generate beam microwaves, which are transmitted along the microwave transmission pipeline (11) to the microwave receiving device (17) in the composite well (3); the microwave receiving device (17) converts the received beam microwaves into microwaves that are scattered in a spherical shape with the microwave receiving device (17) as the center, and continuously heats the leaching liquid to keep it at a corresponding temperature; S5, the leaching liquid continuously exchanges rare earth ions from the top of the ore bed downwards. When it flows to a corresponding depth, the temperature at that location rises, and an infrared thermal imaging probe and a computer (13) are used to form a map. The computer (13) is used to process the monitoring data to obtain a temperature cloud map of each part of the ore bed; S6. Determine the seepage range and flow direction of the leaching solution according to the expansion direction of the temperature rising area in the temperature cloud map, find out the area not impregnated by the leaching solution according to the low temperature area, and increase the leaching solution in the nearby injection wells (2) or increase the number of nearby injection wells (2) so that the uncovered area is impregnated with the leaching solution; S7. Collect the leaching solution from which rare earth ions are leached through the liquid collecting pipe (5) at the bottom of the ore bed.

2. The method for in-situ leaching of rare earth ions by microwave heating according to claim 1, characterized in that: In step S1, the drilling depth of the injection well (2) is 2-5 meters deeper than the top surface of the rare earth deposit (6), and the total depth is 3-6 meters; the composite well (3) is drilled to the middle of the ore layer, and the monitoring well (1) needs to penetrate the rare earth deposit (6), and the depth of the monitoring well (1) is 0.5 to 1 meter deeper than the bottom of the rare earth deposit (6).

3. The method for in-situ leaching of rare earth ions by microwave heating according to claim 1, characterized in that: In step S6, when a discontinuity appears in the extension direction of the temperature rising area or a low temperature area suddenly appears, a crack (16) exists at this location, and the crack (16) is sealed by grouting or caulking.

4. The method for in-situ leaching of rare earth ions by microwave heating according to claim 1, characterized in that: The composite wells (3) are arranged at intervals of 10-20 meters, the monitoring wells (1) are evenly inserted into the composite well (3) network, the monitoring distance is 10-20 meters, the monitoring wells (1) and the composite wells (3) are spaced 5-10 meters apart, and the composite wells (3) and the monitoring wells (1) are arranged alternately.

5. The method for in-situ leaching of rare earth ions by microwave heating according to claim 1, characterized in that: The heating temperature of the leaching solution ranges from 40°C to 80°C.

6. The method for in-situ leaching of rare earth ions by microwave heating according to claim 1, characterized in that: The microwave heating frequency adopts the industrial microwave frequency of 915MHz to 2450MHz.

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