Carbon dioxide based low acid in-situ leach uranium recovery system and method

Abstract

This invention discloses a low-acid in-situ leaching uranium mining system and method based on carbon dioxide, belonging to the field of in-situ leaching uranium mining technology. It solves the problem of insufficient carbon dioxide and poor leaching effect in existing injected formations. The wellhead control device of this invention is located inside the injection well. A dense-phase CO2 injection device stores CO2 after pressure and temperature regulation. The dense-phase CO2 injection device is connected to the injection well through the wellhead control device. An oxidation solution preparation device stores an oxidation solution. The oxidation solution preparation device is also connected to the injection well through the wellhead control device, allowing the pressure and temperature-regulated CO2 and oxidation solution to be discharged into the injection well for uranium leaching. This system can be used for in-situ leaching uranium mining. It can be directly placed at the injection well in the mining site for uranium mining. Using this system can increase the uranium leaching rate and achieve good leaching effect.

Description

Technical Field

[0001] This invention belongs to the field of in-situ leaching uranium mining technology, specifically relating to a low-acid in-situ leaching uranium mining system and method based on carbon dioxide. Background Technology

[0002] In-situ leaching of uranium typically uses carbon dioxide and oxygen in its leaching agent formulations, making it a green, safe, and efficient mining process. Injecting carbon dioxide into the ore-bearing layer can complex uranium into the aqueous solution, while injecting oxygen alters the redox environment of the ore-bearing layer, thus changing the valence state of uranium and making the leaching process more favorable. However, when carbon dioxide dissolves in water, only a small portion combines with water to form carbonic acid; the remainder dissolves as carbon dioxide molecules. Furthermore, carbonic acid has extremely low acidity, with a saturated aqueous solution having a pH of approximately 5.6. In actual production, saturation is rarely achieved, resulting in a weak chemical reaction with carbonate minerals in the uranium ore. Consequently, the carbon dioxide content carried by the leaching agent is insufficient, leading to poor dissolution and often failing to achieve the desired leaching effect.

[0003] Currently, in-situ leaching uranium mines generally use carbon dioxide storage tanks to convert liquid carbon dioxide into gaseous form, which is then added to the water injection pipeline and injected into the well in a gas-liquid mixture. The injection pressure is generally less than 2 MPa. At this pressure, the solubility of carbon dioxide is low, and most of the carbon dioxide escapes during the injection process and accumulates in gaseous form at the injection wellhead, resulting in insufficient carbon dioxide injected into the formation and poor leaching effect. Summary of the Invention

[0004] In view of the above problems, the purpose of this invention is to provide a low-acid in-situ leaching uranium mining system and method based on carbon dioxide, which solves the problem in the prior art that carbon dioxide escapes during the injection process and accumulates in gaseous form at the injection wellhead, resulting in insufficient carbon dioxide injected into the formation and poor leaching effect.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A low-acid in-situ uranium leaching system based on carbon dioxide includes a dense-phase CO2 injection device, an oxidation solution preparation device, and a wellhead control device. The wellhead control device is located inside the injection well. Both the dense-phase CO2 injection device and the oxidation solution preparation device are connected to the wellhead control device. The dense-phase CO2 injection device includes a first storage unit and a CO2 regulation unit connected to the first storage unit. Both the CO2 regulation unit and the oxidation solution preparation device are connected to the wellhead control device. The dense-phase CO2 injection device is used to provide pressure- and temperature-regulated CO2. The dense-phase CO2 injection device is connected to the injection well through the wellhead control device. The oxidation solution preparation device is used to provide an oxidation solution. The oxidation solution preparation device is connected to the injection well through the wellhead control device, so that the pressure- and temperature-regulated CO2 and the oxidation solution are discharged into the injection well for uranium leaching.

[0006] In some embodiments, the CO2 regulating unit includes a CO2 pressure regulating unit and a CO2 temperature regulating unit. One end of the CO2 pressure regulating unit is connected to the first storage unit, and the other end is connected to the CO2 temperature regulating unit. The CO2 temperature regulating unit is connected to the wellhead control device.

[0007] In some embodiments, the CO2 regulating unit further includes a CO2 inlet pipe and a CO2 outlet pipe. The first storage unit is connected to one end of the CO2 pressure regulating unit through the CO2 inlet pipe, and the other end of the CO2 pressure regulating unit is connected to the CO2 temperature regulating unit through the CO2 outlet pipe.

[0008] In some embodiments, the CO2 regulating unit further includes a CO2 return gas pipeline, and one end of the CO2 pressure regulating unit is also connected to the first storage unit through the CO2 return gas pipeline.

[0009] In some embodiments, the CO2 temperature regulating unit is disposed around the outer periphery of the CO2 discharge pipeline.

[0010] In some embodiments, the CO2 regulating unit further includes a body unit, wherein both the CO2 pressure regulating unit and the CO2 temperature regulating unit are disposed within the body unit.

[0011] In some embodiments, the oxidation solution preparation device includes a second storage unit, a third storage unit, and a high-pressure delivery unit. One end of the third storage unit is connected to the second storage unit, and the other end is connected to the high-pressure delivery unit. The high-pressure delivery unit is connected to the wellhead control device.

[0012] In some embodiments, the wellhead control device includes a fluid on / off unit, an exhaust unit, and a monitoring unit. The fluid on / off unit is connected to the dense phase CO2 injection device and the oxidation solution preparation device, respectively. The monitoring unit is connected to the exhaust unit and is used to acquire pressure parameters in the injection well.

[0013] In some embodiments, the system further includes a filtration device disposed in the injection well and the extraction well, respectively.

[0014] In some embodiments, the system further includes a collection device disposed within the extraction well. The collection device includes a fluid suction unit and a pumping pipeline connected to the fluid suction unit, the fluid suction unit being placed within the extraction well.

[0015] Another technical solution of the present invention is implemented as follows: a carbon dioxide-based low-acid in-situ leaching uranium mining method, using the aforementioned carbon dioxide-based low-acid in-situ leaching uranium mining system, includes the following steps: The wellhead control device is placed inside the injection well and connected to the dense phase CO2 injection device and the oxidation solution preparation device, respectively. The oxidation solution preparation device prepares an oxidation solution, stores CO2 in the first storage unit, and transfers the CO2 in the first storage unit to the CO2 regulating unit for pressure and temperature regulation. The oxidation solution and CO2, regulated by pressure and temperature, are injected into the wellhead control device to dissolve the ore layer in the injection well and obtain a leachate.

[0016] Compared with the prior art, the wellhead control device of the present invention is located inside the injection well. The dense phase CO2 injection device is used to store CO2 after pressure and temperature regulation. The dense phase CO2 injection device is connected to the injection well through the wellhead control device. The oxidation solution preparation device is used to store the oxidation solution. The oxidation solution preparation device is connected to the injection well through the wellhead control device, so that the pressure and temperature regulated CO2 and oxidation solution are discharged into the injection well for uranium leaching. The system of the present invention can be used for in-situ leaching uranium mining. The system can be placed directly at the injection well of the mining site for uranium mining. Using this system can increase the uranium leaching rate and has a good leaching effect. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a low-acid in-situ uranium leaching system based on carbon dioxide, provided in Embodiment 1 of the present invention. Figure 2 This is another structural schematic diagram of a low-acid in-situ uranium leaching system based on carbon dioxide provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the structure of a low-acid in-situ uranium leaching system based on carbon dioxide applied to a mineral layer, as provided in Embodiment 1 of the present invention. It should be noted that the accompanying drawings are not necessarily drawn to scale, but are shown only in a schematic manner without affecting the reader's understanding.

[0019] In the diagram, 1. Dense-phase CO2 injection device, 11. First storage unit, 12. CO2 regulation unit, 121. CO2 pressure regulation unit, 122. CO2 temperature regulation unit, 123. CO2 inlet pipeline, 124. CO2 outlet pipeline, 125. CO2 return pipeline, 126. Main unit, 127. Power supply unit, 2. Oxidation solution preparation device, 21. Second storage unit, 22. Third storage unit, 23. High-pressure delivery unit, 3. Wellhead control device, 31. Fluid on / off unit, 32. Exhaust unit, 33. Monitoring unit, 4. Filtration device, 5. Collection device, 51. Fluid suction unit, 52. Suction pipeline. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0022] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0023] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0024] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0025] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0027] Example 1 Embodiment 1 of the present invention provides a low-acid in-situ uranium leaching system based on carbon dioxide, such as... Figure 1As shown, the apparatus includes a dense-phase CO2 injection device 1, an oxidation solution preparation device 2, and a wellhead control device 3. The wellhead control device 3 is located inside the injection well. Both the dense-phase CO2 injection device 1 and the oxidation solution preparation device 2 are connected to the wellhead control device 3. The dense-phase CO2 injection device 1 includes a first storage unit 11 and a CO2 adjustment unit 12 connected to the first storage unit 11. Both the CO2 adjustment unit 12 and the oxidation solution preparation device 2 are connected to the wellhead control device 3. The dense-phase CO2 injection device 1 is used to provide pressure- and temperature-regulated CO2. The dense-phase CO2 injection device 1 is connected to the injection well through the wellhead control device 3. The oxidation solution preparation device 2 is used to provide an oxidation solution. The oxidation solution preparation device 2 is connected to the injection well through the wellhead control device 3, so that the pressure- and temperature-regulated CO2 and the oxidation solution are discharged into the injection well for uranium leaching.

[0028] With the above scheme, the wellhead control device 3 is located inside the injection well. The dense phase CO2 injection device 1 is used to store CO2 after pressure and temperature regulation. The dense phase CO2 injection device 1 is connected to the injection well through the wellhead control device 3. The oxidation solution preparation device 2 is used to store the oxidation solution. The oxidation solution preparation device 2 is connected to the injection well through the wellhead control device 3, so that the pressure and temperature regulated CO2 and the oxidation solution are discharged into the injection well for uranium leaching. The system of the present invention can be used for in-situ leaching uranium mining. The system can be placed directly at the injection well of the mining site for uranium mining. Using this system can increase the uranium leaching rate and achieve good leaching effect.

[0029] More specifically, the first storage unit 11 is used to store liquid CO2 and discharge the liquid CO2 into the CO2 regulating unit 12 for pressure and temperature regulation. In order to make the system more portable and applicable to various uranium production wells, the first storage unit 11 is preferably configured to be mobile, such as a tank truck, or other mobile components that store liquid CO2.

[0030] The oxidation solution preparation device 2 is used to prepare the oxidation solution. This device can internally store the oxidation solution prepared by diluting the oxidant. The concentration of the oxidant can be set according to actual needs. The oxidant can be hydrogen peroxide, manganese dioxide, ferric sulfate, chlorine / hypochlorous acid, oxygen, ozone, etc. The oxidant in this embodiment 1 includes, but is not limited to, the above-mentioned oxidants.

[0031] This scheme further forms a dissolution-oxidation system by mixing CO2 with an oxidation solution. The oxidation solution reacts with low-valence uranium (U2) in the ore. 4+ ) oxidized to a higher oxidation state (U) 6+), forming soluble uranyl ions (UO2²) + In an acidic CO2-H2O environment, carbonate ions in the solution complex with uranium to form uranyl carbonate ions, which then enter the leaching solution for extraction. This method exhibits good dissolution efficiency and accelerates uranium leaching.

[0032] In the specific implementation process of this embodiment 1, such as Figure 2 As shown, the CO2 regulating unit 12 includes a CO2 pressure regulating unit 121 and a CO2 temperature regulating unit 122. One end of the CO2 pressure regulating unit 121 is connected to the first storage unit 11, and the other end is connected to the CO2 temperature regulating unit 122. The CO2 temperature regulating unit 122 is connected to the wellhead control device 3.

[0033] More specifically, the CO2 pressure regulating unit 121 regulates the pressure of the liquid CO2 delivered by the first storage unit 11, and discharges the pressure-regulated liquid CO2 to the CO2 temperature regulating unit 122 for temperature regulation, and then discharges it into the injection well through the wellhead control device 3.

[0034] Furthermore, the liquid CO2 in the first storage unit 11 is converted into supercritical carbon dioxide, or injected into the injection well in liquid form. When injected in supercritical carbon dioxide form, the injection pressure of the dense phase CO2 injection device 1 must reach 7.38 MPa or higher, and the temperature must reach 31.1°C or higher; when injected in liquid form, the injection pressure of the dense phase CO2 injection device 1 must be 2.5 MPa or higher, and the temperature must be between 0 and 20°C.

[0035] In the specific implementation process of this embodiment 1, such as Figure 2 As shown, the CO2 regulating unit 12 further includes a CO2 inlet pipe 123 and a CO2 outlet pipe 124. The first storage unit 11 is connected to one end of the CO2 pressure regulating unit 121 through the CO2 inlet pipe 123, and the other end of the CO2 pressure regulating unit 121 is connected to the CO2 temperature regulating unit 122 through the CO2 outlet pipe 124.

[0036] More specifically, the first storage unit 11 is connected to one end of the CO2 pressure regulating unit 121 through the CO2 liquid inlet pipe 123, so that the liquid CO2 in the first storage unit 11 is transported to the CO2 pressure regulating unit 121. The CO2 pressure regulating unit 121 then transports the pressure-regulated CO2 through the CO2 drain pipe 124 to the CO2 temperature regulating unit 122 for temperature regulation.

[0037] In the specific implementation process of this embodiment 1, such as Figure 2As shown, the CO2 regulating unit 12 also includes a CO2 return gas pipeline 125, and one end of the CO2 pressure regulating unit 121 is also connected to the first storage unit 11 through the CO2 return gas pipeline 125.

[0038] More specifically, a certain amount of gas is generated during the transportation process, and the CO2 gas is reinjected into the first storage unit 11 through the CO2 return pipeline 125.

[0039] Furthermore, after the liquid carbon dioxide comes out of the first storage unit 11, a portion of it will vaporize and be sent back to the first storage unit 11 through the CO2 return gas pipeline 125. The CO2 return gas pipeline 125 is set up to ensure the delivery of liquid carbon dioxide on the one hand, and to ensure that the pressure in the first storage unit 11 is maintained at normal on the other hand.

[0040] In the specific implementation process of this embodiment 1, such as Figure 2 As shown, the CO2 temperature regulating unit 122 is wrapped around the outer periphery of the CO2 discharge pipeline 124.

[0041] More specifically, the CO2 temperature regulating unit 122 is wrapped around the CO2 discharge pipe 124 to heat the liquid CO2 in the pipe more evenly.

[0042] Optionally, the CO2 temperature regulating unit 122 includes a heating element and a temperature control device. The heating element heats the CO2 discharge pipeline 124, and the temperature control device is connected to the heating element. The temperature control device regulates the heating rate, heating time, and heating temperature of the heating element. The temperature control device also has display and alarm functions, displaying the current heating rate, heating time, and heating temperature, and providing voice, buzzer, or indicator light flashing reminders when the specified heating time is reached.

[0043] In the specific implementation process of this embodiment 1, such as Figure 2 As shown, the CO2 regulating unit 12 also includes a body unit 126, and the CO2 pressure regulating unit 121 and the CO2 temperature regulating unit 122 are both located in the body unit 126.

[0044] More specifically, both the CO2 pressure regulating unit 121 and the CO2 temperature regulating unit 122 are located within the main body unit 126, which makes the dense phase CO2 injection device 1 more integrated and easier to transport. It also makes the system occupy a smaller volume and does not take up the area of ​​the mining site.

[0045] Furthermore, the main body unit 126 can be configured as a housing with ventilation holes and a towing hook. Wheels (not shown in the figure) are provided below the housing, which can be connected to a liquid CO2 storage tank truck, making the dense phase CO2 injection device 1 movable as a whole, which is more convenient.

[0046] Furthermore, the CO2 regulating unit 12 also includes a power supply unit 127, which is electrically connected to the CO2 pressure regulating unit 121 and the CO2 temperature regulating unit 122 respectively to supply power to them.

[0047] In the specific implementation process of this embodiment 1, such as Figure 2 As shown, the oxidation solution preparation device 2 includes a second storage unit 21, a third storage unit 22 and a high-pressure delivery unit 23. One end of the third storage unit 22 is connected to the second storage unit 21 and the other end is connected to the high-pressure delivery unit 23. The high-pressure delivery unit 23 is connected to the wellhead control device 3.

[0048] More specifically, the second storage unit 21 is used to store O2, the third storage unit 22 is used to store liquid, and the high-pressure delivery unit 23 delivers the liquid in the third storage unit 22 under high pressure. When the third storage unit 22 stores an oxidizing solution that dilutes the oxidant to a certain concentration, the second storage unit 21 is turned off. When the third storage unit 22 stores water, the second storage unit 21 is turned on and O2 is delivered to the third storage unit 22 to form an oxygen-containing solution.

[0049] Furthermore, the second storage unit 21 is an oxygen tank or other container capable of storing oxygen.

[0050] Furthermore, the pressure of the oxidizing solution injected into the injection well should be higher than the injection pressure of the dense phase CO2 injection device 1.

[0051] In the specific implementation process of this embodiment 1, such as Figure 2 As shown, the wellhead control device 3 includes a fluid on / off unit 31, an exhaust unit 32, and a monitoring unit 33. The fluid on / off unit 31 is connected to the dense phase CO2 injection device 1 and the oxidation solution preparation device 2, respectively. The monitoring unit 33 is connected to the exhaust unit 32 and is used to obtain the pressure parameters in the injection well.

[0052] More specifically, the dense phase CO2 injection device 1 injects supercritical CO2 or liquid CO2 into the injection well through the fluid on / off unit 31, the oxidation solution preparation device 2 injects the oxidation solution into the injection well through the fluid on / off unit 31, and the monitoring unit 33 is used to obtain the pressure parameters in the injection well. When the pressure in the injection well is too high, the pressure is released through the venting unit 32 to protect the injection well and pipeline facilities.

[0053] Furthermore, the two fluid on / off units 31 connected to the dense phase CO2 injection device 1 and the oxidation solution preparation device 2 are opened and closed alternately. That is, when injecting supercritical CO2 or liquid CO2, the fluid on / off unit 31 connecting the oxidation solution preparation device 2 to the wellhead control device 3 is closed, and when injecting oxidation solution, the fluid on / off unit 31 connecting the dense phase CO2 injection device 1 to the wellhead control device 3 is closed. The two alternate. The injected supercritical CO2 or liquid CO2 can continuously mix with formation water and move forward, forming a low-acid, oxygen-rich environment in the entire ore-bearing layer. The high-concentration carbonic acid solution formed after carbon dioxide and water mixes greatly increases the solubility of carbon dioxide under high formation pressure. The pH of the formation water can drop below 4, exhibiting low-acid characteristics and strong corrosive effect. It can accelerate the dissolution of carbonate minerals and uranium minerals in uranium ore and further provide more fluid channels, improving the permeability of the ore-bearing layer.

[0054] Furthermore, such as Figure 3 As shown, after carbon dioxide is injected downhole, it continuously mixes with groundwater and forms three zones during its migration within the ore-bearing formation: dense phase zone a, miscible phase zone b, and leading edge zone c. Dense phase zone a consists of high-pressure injected carbon dioxide, which can be in a supercritical state or a liquid state. Miscible phase zone b is a high-concentration carbonate solution formed by the mixture of dense phase carbon dioxide and water, with a pH below 5. Under high pressure, the pH can even drop below 4, exhibiting low acidity and strong corrosive properties. Leading edge zone c is the leading portion where carbon dioxide displaces the original formation water, with a relatively low carbon dioxide content. As leading edge zone c moves forward, it displaces formation water from the near-wellbore area to deeper formations. Miscible phase zone b follows closely behind, continuously replacing the formation water with a high-concentration carbonate solution. Due to the massive volume of groundwater, dense phase zone a exists only in the near-wellbore area.

[0055] With the continuous injection of carbon dioxide, the entire ore-bearing layer exhibits the low-acidity characteristics of the miscible zone b. Uranium elements in the ore-bearing layer are continuously dissolved and migrated, entering the groundwater to form uranium-containing solutions, and the leachate is collected.

[0056] Optionally, in other embodiments, the fluid injected into the wellhead control device 3 by the dense phase CO2 injection device 1 and the oxidation solution preparation device 2 can also be injected simultaneously.

[0057] Optionally, the monitoring unit 33 can monitor the pressure parameters in the injection well and transmit these parameters to the venting unit 32. The venting unit 32 opens according to its built-in program to vent the pressure in the injection well. When the monitoring unit 33 detects that the pressure in the injection well is within a normal value, the venting unit 32 closes. The monitoring unit 33 has display and alarm functions, displaying the current pressure parameters and providing voice, buzzer, or indicator light flashing reminders when the current pressure parameters exceed a preset threshold.

[0058] Optionally, the system may also include a control device. The monitoring unit 33 transmits pressure parameters to the control device, and the control device issues commands to control the opening and closing of the exhaust unit 32 so that the pressure in the injection well is at a normal value.

[0059] In the specific implementation process of this embodiment 1, such as Figure 2 As shown, the system also includes a filter device 4, which is installed in the injection well and the extraction well respectively.

[0060] More specifically, the filtration device 4 is installed in the injection well to filter out solid impurities such as suspended solids, rust, pipe debris, and chemical precipitates that may be present in the injected fluid (such as supercritical CO2, liquid CO2, or oxidizing solution). This also ensures uniform distribution of the injected fluid, preventing problems such as increased injection pressure and decreased injection volume caused by clogging of formation pores, fractures, or permeability channels, thus preventing damage to the formation's flow capacity. The filtration device 4 is installed in the extraction well to filter formation impurities from the fluid, improving the quality of the leachate, preventing wellbore deformation, and extending the effective production cycle of the well.

[0061] Furthermore, the filter device 4 can be a percolation filter.

[0062] In the specific implementation process of this embodiment 1, such as Figure 2 As shown, the system also includes a collection device 5, which is located in the extraction well. The collection device 5 includes a fluid suction unit 51 and a liquid suction pipeline 52 connected to the fluid suction unit 51. The fluid suction unit 51 is placed in the extraction well.

[0063] More specifically, the fluid suction unit 51 is placed in the extraction well to suction the leachate. The fluid suction unit 51 discharges the suctioned leachate into the suction pipeline 52, which is connected to the collection unit for storing the leachate.

[0064] Furthermore, the fluid suction unit 51 can be selected as a pump with suction function or other components with suction function.

[0065] The extraction pipeline 52 is also equipped with a sampling port for periodically removing the leachate for analysis and testing.

[0066] The workflow provided in Embodiment 1 of this invention is as follows: The first storage unit 11 transports the liquid CO2 stored inside to the CO2 pressure regulating unit 121 for pressure regulation, and then discharges the pressure-regulated liquid CO2 to the CO2 temperature regulating unit 122 for temperature regulation. The fluid after regulation by the CO2 temperature regulating unit 122 is either supercritical carbon dioxide or liquid CO2. The high-pressure delivery unit 23 delivers the liquid in the third storage unit 22 under high pressure. When the third storage unit 22 stores an oxidizing solution diluted with an oxidant to a certain concentration, the second storage unit 21 is closed. When the third storage unit 22 stores water, the second storage unit 21 is opened. 1. O2 is transported to the third storage unit 22 to form an oxygen-containing solution. When supercritical CO2 or liquid CO2 is injected, the fluid on / off unit 31 on the wellhead control device 3 of the oxidation solution preparation device 2 is closed. When the oxidation solution is injected, the fluid on / off unit 31 on the wellhead control device 3 of the dense phase CO2 injection device 1 is closed. The two are carried out alternately. Uranium is leached into the injection well. The filtration device 4 in the injection well and the extraction well filters the fluid in the well. The fluid suction unit 51 is placed in the extraction well to suction the leachate. The fluid suction unit 51 discharges the suctioned leachate into the suction pipeline 52. The suction pipeline 52 is connected to the collection unit, which is used to store the leachate.

[0067] Example 2 A carbon dioxide-based low-acid in-situ uranium leaching method, using the carbon dioxide-based low-acid in-situ uranium leaching system as described in Example 1, includes the following steps: The wellhead control device 3 is placed in the injection well and connected to the dense phase CO2 injection device 1 and the oxidation solution preparation device 2 respectively; The oxidation solution preparation device 2 prepares an oxidation solution, stores CO2 in the first storage unit 11, and transfers the CO2 in the first storage unit 11 to the CO2 regulating unit 12 for pressure and temperature regulation. The oxidation solution and CO2 regulated by pressure and temperature are injected into the wellhead control device 3 to dissolve the ore layer in the injection well and obtain leachate.

[0068] In summary, the wellhead control device 3 of the present invention is located inside the injection well. The dense phase CO2 injection device 1 is used to store CO2 after pressure and temperature regulation. The dense phase CO2 injection device 1 is connected to the injection well through the wellhead control device 3. The oxidation solution preparation device 2 is used to store the oxidation solution. The oxidation solution preparation device 2 is connected to the injection well through the wellhead control device 3, so that the pressure and temperature regulated CO2 and the oxidation solution are discharged into the injection well for uranium leaching. The system of the present invention can be used for in-situ leaching uranium mining. The system can be directly placed at the injection well of the mining site for uranium mining. Using this system can increase the uranium leaching rate and achieve good leaching effect.

[0069] It should be understood that the above are merely illustrative examples and do not constitute any limitation on the technical solutions of the present invention. In specific applications, those skilled in the art can make settings as needed, and the present invention does not impose any restrictions on this.

[0070] It should be noted that the steps described above are merely illustrative and do not limit the scope of protection of this invention. In practical applications, those skilled in the art can select some or all of them to achieve the purpose of this embodiment according to actual needs, and no restrictions are imposed here. The steps of the method described in this application are not limited to being executed sequentially according to the order in the specification; without changing the core technical solution, the execution order of some steps can be adjusted, or they can be implemented in parallel, or steps can be omitted or added in different scenarios. The above modifications or equivalent substitutions do not affect the substantive content of the technical solution of this application and should all fall within the scope of protection of this application.

[0071] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. The scope of protection of this application should be determined by the scope of the claims. Although this application has disclosed the preferred embodiment above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall fall within the scope of the technical solution of this application.

Claims

1. A low-acid in-situ uranium leaching system based on carbon dioxide, characterized in that, The device includes a dense phase CO2 injection device (1), an oxidation solution preparation device (2), and a wellhead control device (3). The wellhead control device (3) is located inside the injection well. Both the dense phase CO2 injection device (1) and the oxidation solution preparation device (2) are connected to the wellhead control device (3). The dense phase CO2 injection device (1) includes a first storage unit (11) and a CO2 regulation unit (12) connected to the first storage unit (11). The CO2 regulation unit (12) and the oxidation solution preparation device (2) are also connected to the wellhead control device (3). All are connected to the wellhead control device (3); the dense phase CO2 injection device (1) is used to set CO2 regulated by pressure and temperature, the dense phase CO2 injection device (1) is connected to the injection well through the wellhead control device (3), the oxidation solution preparation device (2) is used to set the oxidation solution, the oxidation solution preparation device (2) is connected to the injection well through the wellhead control device (3), so that the CO2 regulated by pressure and temperature and the oxidation solution are discharged into the injection well for uranium leaching; The pressure of the oxidizing solution injected into the injection well should be higher than the injection pressure of the dense phase CO2 injection device (1); the CO2 regulating unit (12) includes a CO2 pressure regulating unit (121) and a CO2 temperature regulating unit (122). One end of the CO2 pressure regulating unit (121) is connected to the first storage unit (11), and the other end is connected to the CO2 temperature regulating unit (122). The CO2 temperature regulating unit (122) is connected to the wellhead control device (3); the wellhead control device (3) includes a fluid on / off unit (31), an exhaust unit (32), and a monitoring unit. The fluid on / off unit (31) is connected to the dense phase CO2 injection device (1) and the oxidation solution preparation device (2) respectively. The monitoring unit (33) is connected to the exhaust unit (32). The monitoring unit (33) is used to obtain the pressure parameters in the injection well. The liquid CO2 in the first storage unit (11) is converted into supercritical carbon dioxide, or injected into the injection well in liquid form. When injected in supercritical carbon dioxide form, the injection pressure of the dense phase CO2 injection device (1) must reach 7.38 MPa or above, and the temperature must reach 31.1℃ or above. When injected in liquid form, the injection pressure of the dense phase CO2 injection device (1) is above 2.5 MPa, and the temperature is above 0. Between 20°C; the two fluid on / off units (31) connected to the dense phase CO2 injection device (1) and the oxidation solution preparation device (2) are opened and closed alternately. That is, when injecting supercritical CO2 or liquid CO2, the fluid on / off unit (31) from the oxidation solution preparation device (2) to the wellhead control device (3) is closed, and when injecting oxidation solution, the fluid on / off unit (31) from the dense phase CO2 injection device (1) to the wellhead control device (3) is closed. The two are carried out alternately.

2. The low-acid in-situ uranium leaching system based on carbon dioxide according to claim 1, characterized in that, The CO2 regulating unit (12) further includes a CO2 inlet pipe (123) and a CO2 outlet pipe (124). The first storage unit (11) is connected to one end of the CO2 pressure regulating unit (121) through the CO2 inlet pipe (123), and the other end of the CO2 pressure regulating unit (121) is connected to the CO2 temperature regulating unit (122) through the CO2 outlet pipe (124).

3. The low-acid in-situ uranium leaching system based on carbon dioxide according to claim 2, characterized in that, The CO2 regulating unit (12) also includes a CO2 return gas pipeline (125), and one end of the CO2 pressure regulating unit (121) is connected to the first storage unit (11) through the CO2 return gas pipeline (125).

4. The low-acid in-situ uranium leaching system based on carbon dioxide according to claim 2, characterized in that, The CO2 temperature regulating unit (122) is wrapped around the CO2 discharge pipeline (124).

5. The low-acid in-situ uranium leaching system based on carbon dioxide according to any one of claims 2-4, characterized in that, The CO2 regulating unit (12) also includes a body unit (126), and the CO2 pressure regulating unit (121) and the CO2 temperature regulating unit (122) are both located in the body unit (126).

6. The low-acid in-situ uranium leaching system based on carbon dioxide according to any one of claims 1-4, characterized in that, The oxidation solution preparation device (2) includes a second storage unit (21), a third storage unit (22) and a high-pressure delivery unit (23). One end of the third storage unit (22) is connected to the second storage unit (21), and the other end is connected to the high-pressure delivery unit (23). The high-pressure delivery unit (23) is connected to the wellhead control device (3).

7. The low-acid in-situ uranium leaching system based on carbon dioxide according to claim 6, characterized in that, The system also includes a filtration device (4), which is located in the injection well and the extraction well respectively.

8. The low-acid in-situ uranium leaching system based on carbon dioxide according to claim 7, characterized in that, The system also includes a collection device (5) located in the extraction well. The collection device (5) includes a fluid suction unit (51) and a liquid suction pipeline (52) connected to the fluid suction unit (51). The fluid suction unit (51) is placed in the extraction well.

9. A carbon dioxide-based low-acid in-situ leaching uranium mining method, using the carbon dioxide-based low-acid in-situ leaching uranium mining system as described in any one of claims 1-8, characterized in that, Includes the following steps: The wellhead control device (3) is placed in the injection well and connected to the dense phase CO2 injection device (1) and the oxidation solution preparation device (2) respectively; The oxidation solution preparation device (2) prepares an oxidation solution, stores CO2 in the first storage unit (11), and transfers the CO2 in the first storage unit (11) to the CO2 regulating unit (12) for pressure and temperature regulation. The oxidation solution and CO2 regulated by pressure and temperature are injected into the wellhead control device (3) to dissolve the ore layer in the injection well and obtain leachate.

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