Single-well injection-production method for low-permeability sandstone-type uranium deposits

Abstract

The present application discloses a single-well injection and production method for a low-permeability sandstone-type uranium mine, belonging to the technical field of in-situ uranium leaching, comprising: drilling an injection and production well from the ground into a uranium ore layer; pumping liquid carbon dioxide into the uranium ore layer and soaking the well; injecting a leaching agent into the uranium ore layer in stages, and soaking the well every time a leaching agent injection is completed; extracting a leachate until the uranium concentration in the leachate decreases by 10% compared with the initial concentration or the uranium concentration in the leachate decreases to a preset concentration; adding carbon dioxide and a leaching agent to the tail liquid formed after uranium recovery in the leachate to saturate the tail liquid, and reinjecting the saturated tail liquid into the uranium ore layer; and a cyclic operation step.

Description

Technical Field

[0001] The present application belongs to the technical field of in-situ leaching of uranium, and specifically relates to a single-well injection and mining method for low-permeability sandstone-type uranium mines. Background Art

[0002] With the continuous advancement of my country's uranium exploration work of "deep exploration and blind spot detection", a number of complex sandstone uranium deposits such as low permeability and isolated islands have been discovered. How to effectively develop such uranium deposits has become a technical problem that needs to be overcome in the field of in-situ leaching development.

[0003] Conventional in-situ leaching requires the coordinated operation of injection and extraction wells, but this approach has significant drawbacks. For low-permeability uranium deposits, effective communication between injection and extraction wells is difficult, resulting in low mining efficiency. Furthermore, in small, isolated uranium deposits, the cost of constructing multiple wells for coordinated development is prohibitive and economically unjustifiable. Furthermore, the conventional coordinated development model requires long-term, uninterrupted cycles of injection and extraction, which consumes significant energy and contributes to high mining costs.

[0004] Experience in oil and gas reservoir development demonstrates that fracturing and other reservoir transformation methods can effectively improve permeability and mineral recovery in low-permeability reservoirs. This approach holds significant promise for the development of low-permeability uranium deposits. However, conventional transformation methods, lacking effective synergistic technologies, struggle to achieve the desired results. Even if fractures can be formed, without an effective leaching system and enhanced leaching methods, the leachant's reach within the uranium deposit remains limited, preventing it from evenly dispersing throughout the target area. This severely impacts leaching efficiency, hindering the mining efficiency and economic benefits of low-permeability sandstone-type uranium deposits.

[0005] Therefore, it is urgent to develop a single-well injection-production method for low-permeability sandstone uranium deposits. This method requires the synergistic effects of single-well reservoir reconstruction, enhanced leaching, and well soaking technologies to achieve economical and efficient development of low-permeability, isolated, and complex sandstone uranium deposits. Summary of the Invention

[0006] In view of this, the present application provides a single-well injection and production method for low-permeability sandstone uranium mines, the main purpose of which is to overcome the many shortcomings of existing conventional methods in the mining of low-permeability and island-shaped complex sandstone uranium mines, specifically including: for low-permeability uranium ore layers, it is difficult to establish effective communication and low mining efficiency through the coordinated development of conventional two wells (injection wells and leaching wells). Through the single-well injection and production method, the synergistic effect of single-well reservoir transformation, enhanced leaching (pumping liquid carbon dioxide into the uranium ore layer, injecting leaching agents in stages, etc.) and well soaking technology is utilized to improve the permeability and leaching effect of the uranium ore layer, thereby solving the problem of inter-well communication and improving mining efficiency; for small-scale (isolated island-shaped) uranium mining areas, the cost of conventionally drilling two wells is too high, while this method adopts single-well injection and production, avoiding the high cost of drilling two wells, which is more reasonable from an economic point of view and reduces mining costs.

[0007] To achieve the above objectives, this application mainly provides the following technical solutions:

[0008] The present application provides a single-well injection-production method for a low-permeability sandstone-type uranium deposit, comprising:

[0009] Drilling injection and production wells from the surface into the uranium ore layer;

[0010] Pumping liquid carbon dioxide into the uranium ore layer and simmering the well;

[0011] Injecting leaching agent into the uranium ore layer in stages, and soaking the well after each leaching agent injection;

[0012] Extracting the leachate until the uranium concentration in the leachate decreases by 10% compared to the initial concentration or the uranium concentration in the leachate decreases to a preset concentration;

[0013] Adding carbon dioxide and leaching agent to the tail liquid formed after uranium recovery to make the tail liquid reach saturation, and then injecting the saturated tail liquid back into the uranium ore layer;

[0014] Repeating the steps of injecting a leaching agent into the uranium ore layer in stages, soaking the well each time a leaching agent injection is completed, extracting the leachate until the uranium concentration in the leachate is reduced by 10% compared with the initial concentration or the uranium concentration in the leachate is reduced to a preset concentration, and adding carbon dioxide and a leaching agent to the tail liquid formed after uranium recovery in the leachate to saturate the tail liquid, and reinjecting the saturated tail liquid into the uranium ore layer.

[0015] Optionally, the pumping pressure of the liquid carbon dioxide is 1.1 to 1.2 times the fracture pressure of the uranium ore layer.

[0016] Optionally, in the step of pumping liquid carbon dioxide into the uranium ore layer and soaking the well, the soaking time is 48 to 72 hours to ensure that a large-scale complex fracture network structure suitable for in-situ leaching is formed in the uranium ore layer.

[0017] Optionally, the step of injecting a leaching agent into the uranium ore layer in stages and soaking the well after each leaching agent injection is completed comprises:

[0018] First stage injection of leaching agent and well soaking;

[0019] Second stage of solvent injection and well soaking.

[0020] Optionally, in the step of injecting leaching agent into the uranium ore layer in stages and soaking the well after each leaching agent injection, the injection amount of leaching agent in the second stage is the same as the injection amount of leaching agent in the first stage or the injection amount of leaching agent in the second stage is proportionally reduced compared with the injection amount of leaching agent in the first stage.

[0021] Optionally, in the steps of injecting the leaching agent in the first stage and soaking the well, the soaking time is 24 to 48 hours; in the steps of injecting the leaching agent in the second stage and soaking the well, the soaking time is 96 to 168 hours.

[0022] Optionally, in the step of injecting leaching agent into the uranium ore layer in stages and soaking the well after each leaching agent injection, when the soaking time after the first stage leaching agent injection is 48 hours, the injection amount of leaching agent in the second stage is the same as the injection amount of leaching agent in the first stage.

[0023] Optionally, in the step of injecting leaching agent into the uranium ore layer in stages and soaking the well after each leaching agent injection, when the soaking time after the first stage leaching agent injection is less than 48 hours, the injection amount of the leaching agent in the second stage is proportionally reduced compared to the injection amount of the leaching agent in the first stage.

[0024] Optionally, in the step of injecting leaching agent into the uranium ore layer in stages and soaking the well after each leaching agent injection, when the soaking time after the first stage leaching agent injection is 24 hours, the injection amount of leaching agent in the second stage is half of the injection amount of leaching agent in the first stage.

[0025] Optionally, in the step of injecting a leaching agent into the uranium ore layer in stages and soaking the well after each leaching agent injection is completed, the leaching agent used is a hydrogen peroxide solution with a mass concentration of 3% to 5% or a potassium permanganate solution with a mass concentration of 0.1% to 0.3%, and the injection rate of the leaching agent in each stage is 0.1 to 0.5 cubic meters per hour.

[0026] By means of the above technical solution, this application has at least the following beneficial effects:

[0027] The single-well injection and production method for low-permeability sandstone uranium deposits provided in the embodiments of the present application adopts a single-well injection and production method, eliminating the need to drill a well field injection and production structure with at least two pumping and injection wells as in conventional methods, thereby reducing drilling costs. At the same time, it avoids the huge energy consumption caused by the long-term uninterrupted cycle injection and production of conventional collaborative development models, reduces operating costs, and is more economically reasonable. It is particularly suitable for the mining of complex sandstone uranium deposits such as low-permeability and island-shaped uranium deposits. Specifically, by pumping liquid carbon dioxide into the uranium ore layer and simmering the well, and injecting a leaching agent in stages and simmering the well, it helps to achieve reservoir transformation under single-well conditions, promote the formation and expansion of cracks in the uranium ore layer, improve the permeability of the uranium ore layer, and enable the leaching agent to diffuse more evenly throughout the target area and fully contact the uranium element, thereby improving the leaching efficiency and thus improving the mining efficiency. By using the uranium concentration in the leachate to be reduced by 10% compared to the initial concentration or the uranium concentration in the leachate to be reduced to a preset concentration as the standard when extracting the leachate, the mining process can be accurately controlled, over-mining or under-mining can be avoided, and the rational development and utilization of uranium resources can be ensured. By treating the tail liquid formed after uranium recovery from the leachate, adding carbon dioxide and leaching agents to make it reach a saturated state and then injecting it back into the uranium ore layer, the recycling of resources is achieved, resource waste and environmental pollution are reduced, and the sustainability of the entire mining process is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of a single-well injection-production method for a low-permeability sandstone-type uranium mine according to an optional embodiment of the present application. DETAILED DESCRIPTION

[0029] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

[0030] In this embodiment, a single well injection and production method for low permeability sandstone type uranium ore is provided. Figure 1 As shown, the method includes:

[0031] Step S101: drilling an injection well into a uranium ore layer from the ground.

[0032] The single-well injection and mining method for low-permeability sandstone-type uranium ore provided in the embodiment of the present application can be applied to fields such as in-situ leaching of uranium, and can be specifically applied to mining operations of low-permeability ore layers or isolated island-shaped ore sections. When conducting mining operations of low-permeability ore layers or isolated island-shaped ore sections, first, survey the geological conditions, determine the specific location of the low-permeability sandstone-type uranium ore layer to be mined, and arrange drill holes in the length direction from the surface to the uranium ore layer. Here, professional drilling equipment is used to drill vertically or obliquely from the ground to the underground uranium ore layer to form an injection and mining well. It should be noted that the injection and mining well is the channel for all subsequent operations, which is used to inject various substances into the uranium ore layer and extract leachate.

[0033] Step S201: pumping liquid carbon dioxide into the uranium ore layer and soaking the well.

[0034] In this embodiment, a high-pressure pump can be used to inject liquid carbon dioxide into the uranium ore layer through an injection well. Once the liquid carbon dioxide enters the uranium ore layer, it undergoes physical and chemical changes due to pressure and temperature. Well soaking involves sealing the wellhead after injecting the liquid carbon dioxide, allowing the carbon dioxide to diffuse within the uranium ore layer for a period of time. This allows the carbon dioxide to diffuse to the far ends of the uranium ore layer, creating a wider area that can be effectively reached by the leachant.

[0035] It should be noted that the injection pressure of the liquid CO2 is 1.1 to 1.2 times the fracture pressure of the uranium ore layer. By setting the injection pressure of the liquid CO2 above the fracture pressure of the uranium ore layer, the powerful impact force of the liquid CO2 when pumped into the uranium ore layer can initially induce fractures in the uranium ore layer. Once the liquid CO2 successfully enters the uranium ore layer, it continuously diffuses within the existing fractures. Simultaneously, due to changes in temperature and pressure conditions, the liquid CO2 gradually vaporizes into a gaseous state, significantly expanding in volume. This expansion further expands the fractures, causing them to extend and branch within the uranium ore layer, effectively increasing the propagation of the fractures and ultimately forming multiple fracture patterns. With a more complex fracture network, the leaching agent's reach within the uranium ore layer is significantly expanded, allowing it to more fully penetrate the uranium ore area, greatly increasing the contact area between the leaching agent and the uranium ore and the reaction opportunities. This allows the uranium to react more fully with the leaching agent, significantly improving the leaching efficiency of the uranium, and ultimately achieving the goal of improving the mining efficiency and economic benefits of low-permeability sandstone uranium deposits.

[0036] In some actual cases, measurements have shown that the fracture pressure of uranium deposits is 12 MPa. Based on this, during actual operation, the liquid CO2 injection pressure was controlled at 13.2 MPa, with an injection rate of 1.5 cubic meters per minute, and continued for 30 minutes. Microseismic monitoring technology subsequently revealed that the fracturing operation successfully created a network of microfractures with a radius ranging from 1.2 to 1.8 meters, with a vertical span effectively controlled to within 4.2 meters. The process did not damage the roof and floor aquicludes. After the liquid CO2 injection was completed, a wellbore was immediately maintained to maintain pressure, with a duration of 60 hours. The temperature of the uranium deposit was maintained at a stable 20°C, allowing the injected liquid CO2 to rapidly vaporize. The gaseous CO2 reacted chemically with the water in the formation, producing carbonic acid. This reaction lowered the pH of the deposit from its initial value of 7.42 to 6.71, creating a slightly acidic groundwater environment. This significantly reduces the likelihood of subsequent injection of leaching agents reacting with the surrounding rock and causing precipitation. During the 60-hour soaking period, gaseous carbon dioxide, through the microcracks created by the initial fracturing, continuously diffused toward the distal end of the ore layer, gradually establishing a wider area where the leaching agent could fully act, creating extremely favorable conditions for subsequent leaching and mining operations.

[0037] Step S301: injecting a leaching agent into the uranium ore layer in stages, and soaking the well after each leaching agent injection is completed.

[0038] In this embodiment, the leaching agent can be a hydrogen peroxide solution with a mass concentration in the range of 3% to 5%, or a potassium permanganate solution with a mass concentration in the range of 0.1% to 0.3%. It should be noted that whether it is a hydrogen peroxide solution with a mass concentration of 3% to 5% or a potassium permanganate solution with a mass concentration of 0.1% to 0.3%, when used to oxidize uranium, a certain reaction time is required to complete the oxidation process. During this period, if the leaching agent is excessive, it will react with other minerals in the uranium ore. Taking iron ions as an example, excess leaching agent will react with iron, oxidizing it to trivalent iron, thereby producing a precipitate. In view of this, this embodiment adopts a phased injection method for leachant. On the one hand, this ensures that the leachant is effectively utilized, allowing the uranium oxide reaction to proceed fully and improving the uranium leaching efficiency. On the other hand, by controlling the leachant injection amount at each stage, it can effectively suppress the reaction of excessive leachant with other metals, thereby avoiding the blockage of ore layer pores caused by precipitation, ensuring the flow of leachant in the uranium ore layer, and creating favorable conditions for the smooth progress of subsequent mining operations. The purpose of soaking the well after each leachant injection is to allow the leachant and uranium ore sufficient time to react, improve the dissolution efficiency of the uranium element, and enable the leachant to diffuse more evenly to all parts of the uranium ore layer, contacting and reacting with as much uranium ore as possible.

[0039] Here, taking the case where the leachant is injected into the uranium ore layer twice as an example, the injection amount of the leachant in each stage is explained. In actual application scenarios, the soaking time after the first stage injection of the leachant is in a range interval, and the interval has an upper limit and a lower limit. The specific value can be flexibly determined according to the processing volume of the leachate, and this application does not limit this. When the soaking time after the first stage injection of the leachant reaches the upper limit, the injection amount of the leachant in the second stage is equal to that in the first stage. This is because the longer soaking time can make the leachant injected in the first stage be more fully consumed, the reaction is more thorough, and there is still a large space and demand in the ore layer to accommodate the same amount of leachant as in the first stage, so the second stage can still be injected in large quantities. When the soaking time after the first stage injection of the leachant is less than the upper limit, the injection amount of the leachant in the second stage will be proportionally reduced compared to the first stage. This is because the short soaking time prevents the leachant injected in the first phase from fully reacting and being consumed, resulting in a relatively high concentration of leachant remaining in the ore layer. If the second phase continues to be injected at the same rate as the first phase, an overdose of leachant will result, which will not only waste resources but may also cause adverse consequences such as excessive reaction with other minerals and precipitation, affecting subsequent mining operations. Specifically, when the soaking time after the first phase of leachant injection reaches the lower limit, the second phase of leachant injection is reduced to half the amount injected in the first phase.

[0040] Furthermore, in this embodiment, the soaking time after each stage of leachant injection is clearly defined: the soaking time after the first stage of leachant injection ranges from 24 to 48 hours; the soaking time after the second stage of leachant injection ranges from 96 to 168 hours. It should be noted that the primary purpose of the first stage of leachant injection is to initially contact the uranium ore with the leachant and initiate the oxidative dissolution reaction. Within 24 to 48 hours, the leachant rapidly diffuses into the ore layer and initially reacts with the uranium ore, quickly dissolving some of the readily soluble uranium. In the second stage, after the first stage of reaction, the remaining refractory uranium ore requires a longer period of time to fully interact with the leachant. As the reaction proceeds, the reaction environment within the ore layer becomes more complex, and the reaction rate gradually decreases. Therefore, a longer soaking time of 96 to 168 hours is required to allow the leachant to continuously penetrate into the finer pores and deeper into the ore layer, fully reacting with the remaining uranium ore and improving the overall uranium leaching rate.

[0041] In some actual cases, the parameters are as follows: The first phase injected a 5% hydrogen peroxide solution at a rate of 0.3 cubic meters per hour, for a cumulative injection volume of 8 cubic meters. The well was then soaked for 48 hours. The second phase injected a 5% hydrogen peroxide solution at a rate of 0.2 cubic meters per hour, for a total volume of 8 cubic meters. After the injections were completed, the well was soaked for 168 hours.

[0042] Step S401: extracting the leachate until the uranium concentration in the leachate decreases by 10% compared to the initial concentration or the uranium concentration in the leachate decreases to a preset concentration.

[0043] In this embodiment, a uranium-containing leachate is extracted from the uranium ore layer to the surface via an injection well using a submersible pump. During the extraction process, the uranium concentration in the leachate is continuously monitored. Extraction is stopped when the uranium concentration in the leachate decreases by 10% compared to the initial concentration at the beginning of extraction, or when the uranium concentration in the leachate drops to a pre-set lower concentration. This step is intended to control the degree of uranium leaching, ensuring that a certain level of mining efficiency and economic benefits are achieved while avoiding over-exploitation and resource waste.

[0044] In some cases, submersible pumps are used to extract leachate at a rate of 3 cubic meters per hour. Real-time monitoring of uranium concentrations shows that within the first 24 hours of extraction, the average uranium concentration in the leachate was 96 mg / L. Subsequently, as extraction progressed, the uranium concentration gradually decreased. After 72 hours of continuous extraction, the uranium concentration in the leachate had dropped to 86 mg / L.

[0045] Step S501: adding carbon dioxide and a leaching agent to the tail liquid formed after the uranium is recovered from the leachate to make the tail liquid reach a saturated state, and then injecting the saturated tail liquid back into the uranium ore layer.

[0046] In this embodiment, after uranium is recovered from the leachate, the remaining tail liquid still contains some unreacted components, as well as potentially lost carbon dioxide and leaching agent. Carbon dioxide and leaching agent are added to the tail liquid to saturate it, i.e., to achieve optimal concentrations of the various components in the tail liquid for effective leaching of uranium. The saturated tail liquid is then reinjected into the uranium ore layer through the injection-production well, achieving resource recycling, reducing environmental pollution, and lowering mining costs.

[0047] In some actual cases, carbon dioxide (to a concentration of 300 mg / L) and hydrogen peroxide (to a concentration of 1%) are added to the tailings. After the addition is completed, the treated tailings are reinjected into the original uranium ore layer.

[0048] Step S601: repeatedly injecting a leaching agent into the uranium ore layer in stages, and soaking the well and extracting the leachate each time the leaching agent injection is completed, until the uranium concentration in the leachate is reduced by 10% compared with the initial concentration or the uranium concentration in the leachate is reduced to a preset concentration, and carbon dioxide and a leaching agent are added to the tail liquid formed after uranium recovery in the leachate to saturate the tail liquid, and the saturated tail liquid is reinjected into the uranium ore layer.

[0049] In this embodiment, the uranium ore layer is continuously leached and mined in a cycle, following the sequence of steps S301, S401, and S501, to maximize the extraction of uranium from the uranium ore until the uranium resources in the uranium ore layer are mined to a level that is no longer economically or technically feasible. This cyclic operation continuously improves uranium mining efficiency, fully utilizes resources, and achieves sustainable mining of low-permeability sandstone-type uranium deposits.

[0050] In some actual cases, steps S301 (injecting a leachant into the uranium ore layer in stages, with the well soaked after each injection), S401 (extracting the leachate until the uranium concentration in the leachate decreases by 10% compared to the initial concentration or reaches a preset concentration), and S501 (adding carbon dioxide and a leachant to the tailings formed after uranium recovery to saturate the tailings, which is then reinjected into the uranium ore layer) were repeated three times. Throughout the entire leaching process, the average uranium concentration of the leached uranium reached 80.2 mg / L. This demonstrates that the single-well injection-mining method for low-permeability sandstone uranium deposits provided in this embodiment effectively improves the leaching concentration of uranium ore in low-permeability sandstone reservoirs, effectively achieving the goals of reducing mining costs and improving mining efficiency.

[0051] By applying the technical solution of this embodiment, a single-well injection-production method is adopted, and there is no need to drill a well field injection-production structure with at least two pumping and injection wells as in conventional methods, thus reducing drilling costs. At the same time, it avoids the huge energy consumption caused by the long-term uninterrupted cycle injection-production of the conventional collaborative development model, reduces operating costs, and is more economically reasonable. It is particularly suitable for the mining of complex sandstone uranium mines such as low permeability and island-shaped mines. Specifically, by pumping liquid carbon dioxide into the uranium ore layer and suffocating the well, and injecting leaching agents in stages and suffocating the well, it helps to achieve reservoir transformation under single-well conditions, promote the formation and expansion of cracks in the uranium ore layer, improve the permeability of the uranium ore layer, and enable the leaching agent to diffuse more evenly throughout the target area and fully contact the uranium element, thereby improving the leaching efficiency and thus improving the mining efficiency. By using the uranium concentration in the leachate to be reduced by 10% compared to the initial concentration or the uranium concentration in the leachate to be reduced to a preset concentration as the standard when extracting the leachate, the mining process can be accurately controlled, over-mining or under-mining can be avoided, and the rational development and utilization of uranium resources can be ensured. By treating the tail liquid formed after uranium recovery from the leachate, adding carbon dioxide and leaching agents to make it reach a saturated state and then injecting it back into the uranium ore layer, the recycling of resources is achieved, resource waste and environmental pollution are reduced, and the sustainability of the entire mining process is improved.

[0052] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0053] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application. The above are merely preferred embodiments of the present application. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present application, and such improvements and variations shall also be considered within the scope of protection of the present application.

Claims

1. A single-well injection and production method for low-permeability sandstone-type uranium deposits, characterized in that: include: Drilling injection and production wells from the surface into the uranium ore layer; Pumping liquid carbon dioxide into the uranium ore layer and then simmering the well. The pumping pressure of the liquid carbon dioxide is 1.1 to 1.2 times the fracture pressure of the uranium ore layer. The simmering time is 48 to 72 hours to ensure that a large-scale complex fracture network structure suitable for in-situ leaching is formed in the uranium ore layer. Injecting a leachant into the uranium ore layer in stages, and soaking the well after each leachant injection is completed, wherein the injecting the leachant into the uranium ore layer in stages includes a first stage and a second stage, wherein the soaking time after the injection of the leachant in the first stage is 24 to 48 hours, and the soaking time after the injection of the leachant in the second stage is 96 to 168 hours; when the soaking time after the injection of the leachant in the first stage is 48 hours, the injection amount of the leachant in the second stage is the same as the injection amount of the leachant in the first stage; when the soaking time after the injection of the leachant in the first stage is less than 48 hours, the injection amount of the leachant in the second stage is proportionally reduced, and when the soaking time after the injection of the leachant in the first stage is 24 hours, the injection amount of the leachant in the second stage is half of the injection amount of the leachant in the first stage; Extracting the leachate until the uranium concentration in the leachate decreases by 10% compared to the initial concentration or the uranium concentration in the leachate decreases to a preset concentration; Adding carbon dioxide and leaching agent to the tail liquid formed after uranium recovery to make the tail liquid reach saturation, and then injecting the saturated tail liquid back into the uranium ore layer; Repeating the steps of injecting a leaching agent into the uranium ore layer in stages, soaking the well each time a leaching agent injection is completed, extracting the leachate until the uranium concentration in the leachate is reduced by 10% compared with the initial concentration or the uranium concentration in the leachate is reduced to a preset concentration, and adding carbon dioxide and a leaching agent to the tail liquid formed after uranium recovery in the leachate to saturate the tail liquid, and reinjecting the saturated tail liquid into the uranium ore layer.

2. The single-well injection-production method for low-permeability sandstone-type uranium deposits according to claim 1, characterized in that: In the step of injecting a leaching agent into the uranium ore layer in stages and soaking the well after each leaching agent injection, the leaching agent used is a hydrogen peroxide solution with a mass concentration of 3% to 5% or a potassium permanganate solution with a mass concentration of 0.1% to 0.3%, and the injection rate of the leaching agent in each stage is 0.1 to 0.5 cubic meters per hour.

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