High pressure leaching system and high pressure leaching method based on carbon dioxide and oxygen

Abstract

The application discloses a high-pressure leaching system and a high-pressure leaching method based on carbon dioxide and oxygen. The high-pressure leaching system comprises a carbon dioxide injection device, a high-pressure oxygen injection device and a high-pressure liquid injection device. The carbon dioxide injection device is connected with a liquid injection pipeline through a carbon dioxide gas conveying pipeline and a liquid carbon dioxide conveying pipeline. One end of the liquid injection pipeline is connected with a water storage tank, and the other end of the liquid injection pipeline is connected with an injection well. The other ends of the carbon dioxide gas conveying pipeline and the liquid carbon dioxide conveying pipeline are connected with a liquid carbon dioxide storage tank. The high-pressure oxygen injection device comprises a high-pressure oxygen conveying pipeline. One end of the high-pressure oxygen conveying pipeline is connected with a liquid oxygen storage tank, and the other end of the high-pressure oxygen conveying pipeline is connected with the injection well. The high-pressure injection of gaseous or liquid carbon dioxide increases the acidity of underground water, accelerates the dissolution of minerals and the complexation of uranium. The high-pressure injection of oxygen can quickly oxidize uranium-containing minerals and reducing substances, and improve the leaching rate of uranium.

Description

Technical Field

[0001] This invention relates to the field of in-situ leaching uranium mining technology, and more particularly to a high-pressure leaching system and method based on carbon dioxide and oxygen. Background Technology

[0002] In-situ leaching is a mining and smelting process in which a suitable amount of leaching agent is prepared on the surface according to a certain formula and injected into the underground ore body through a borehole. During the underground seepage process, the leaching solution selectively dissolves uranium in the ore, and the resulting uranium-containing solution is lifted to the surface, thereby extracting and recovering uranium metal.

[0003] Currently, leaching agent formulations mostly use carbon dioxide and oxygen, which is a green, safe, and efficient mining process. Injecting carbon dioxide into the ore-bearing strata can complex the target element uranium into the aqueous solution, while injecting oxygen can change the redox environment of the ore-bearing strata, thereby altering the valence state of uranium in the ore and making the uranium leaching process more favorable. However, for ore-bearing strata with low permeability and difficult injection and extraction, due to the dense rocks, poor permeability, and slow groundwater migration, the injection pressure used in conventional uranium leaching is generally below 2 MPa. Therefore, the low injection pressure and small flow rate result in insufficient carbon dioxide and oxygen content, leading to poor dissolution and oxidation performance, often failing to achieve the ideal leaching effect. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] In view of this, the present invention provides a high-pressure leaching system and method based on carbon dioxide and oxygen. Through the cooperation of a carbon dioxide injection device, a high-pressure oxygen injection device and a high-pressure liquid injection device, gaseous or liquid carbon dioxide is injected under high pressure to increase the acidity of groundwater, accelerate mineral dissolution and uranium complexation, and high-pressure oxygen injection can rapidly oxidize uranium-containing minerals and reducing substances, thereby improving the uranium leaching rate.

[0006] Specifically, the following technical solutions are included:

[0007] An embodiment of a first aspect of the present invention provides a high-pressure leaching system based on carbon dioxide and oxygen, comprising a liquid carbon dioxide storage tank and a liquid oxygen storage tank. The high-pressure leaching system further includes: a carbon dioxide injection device, a high-pressure oxygen injection device, and a high-pressure liquid injection device. The carbon dioxide injection device includes a carbon dioxide gas delivery pipeline and a liquid carbon dioxide delivery pipeline. The high-pressure liquid injection device includes an injection pipeline, one end of which is connected to a water storage tank, and the other end of which is connected to an injection well. A gas-liquid mixer is provided on the injection pipeline. One end of the carbon dioxide gas delivery pipeline is connected to the liquid carbon dioxide storage tank, and the other end of which is connected to the gas-liquid mixer. One end of the liquid carbon dioxide delivery pipeline is connected to the liquid carbon dioxide storage tank, and the other end of which is connected to the injection well. The high-pressure oxygen injection device includes a high-pressure oxygen delivery pipeline, one end of which is connected to the liquid oxygen storage tank, and the other end of which is connected to the injection well.

[0008] Optionally, the carbon dioxide injection device further includes: a low-pressure valve, a first air-bath vaporizer, a first electrically heated vaporizer, a gas flow regulating valve, a carbon dioxide gas pressure gauge, a first gas mass flow meter, and a check valve, which are sequentially arranged on the carbon dioxide gas delivery pipeline. The low-pressure valve is located at the end of the carbon dioxide gas delivery pipeline near the liquid carbon dioxide storage tank, and the check valve is located at the end of the carbon dioxide gas delivery pipeline near the gas-liquid mixer.

[0009] The liquid carbon dioxide delivery pipeline is sequentially equipped with a high-pressure valve, a first high-pressure cryogenic liquid pump, a liquid pressure gauge, a high-pressure flow meter, and a first high-pressure check valve. The high-pressure valve is located at the end of the liquid carbon dioxide delivery pipeline near the liquid carbon dioxide storage tank.

[0010] Optionally, the high-pressure oxygen injection device further includes a second high-pressure cryogenic liquid pump, a second air-bath vaporizer, a second electric heating vaporizer, a high-pressure oxygen buffer tank group, an oxygen pressure gauge, a second gas mass flow meter, a second high-pressure check valve, and an oxygen valve, which are sequentially arranged on the high-pressure oxygen delivery pipeline. The oxygen valve is located at one end of the high-pressure oxygen delivery pipeline near the injection well.

[0011] Optionally, the high-pressure injection device further includes: a centrifugal pump, an injection flow meter, a low-pressure gauge, the gas-liquid mixer, a high-pressure injection pump, a high-pressure gauge, a third high-pressure check valve, and an injection valve, which are sequentially arranged on the injection pipeline. The injection valve is located at one end of the injection pipeline near the injection well.

[0012] Optionally, the high-pressure leaching system further includes:

[0013] A high-pressure gas-liquid mixer is provided, wherein the end of the liquid injection pipeline away from the water storage tank and the end of the high-pressure oxygen delivery pipeline away from the liquid oxygen storage tank are both connected to the high-pressure gas-liquid mixer, and a high-pressure safety valve is provided on the high-pressure gas-liquid mixer;

[0014] The injection well is provided with a wellhead sealing device at the open end. At least part of the high-pressure gas-liquid mixer is installed inside the injection well after passing through the wellhead sealing device. An injection seepage filter is provided on the injection well. The injection seepage filter is located in the ore body, which is located in the ore-bearing aquifer.

[0015] Optionally, the high-pressure leaching system further includes a liquid extraction device, the liquid extraction device comprising:

[0016] The extraction well is equipped with an extraction seepage filter located within the ore body. The wellhead of the extraction well is equipped with a wellhead device, and a submersible pump is installed inside the extraction well.

[0017] The liquid extraction pipeline is connected to the submersible pump at one end and to the hydrometallurgical plant at the other end. A liquid extraction flow meter and a sampling port are sequentially installed on the liquid extraction pipeline.

[0018] A second aspect of the present invention provides a high-pressure leaching method based on carbon dioxide and oxygen, utilizing the aforementioned high-pressure leaching system, the high-pressure leaching method comprising the following steps:

[0019] Based on formation parameters, the initial injection volume and initial injection pressure of the high-pressure injection device are obtained;

[0020] Based on the initial injection volume and the required carbon dioxide and oxygen consumption, the carbon dioxide injection volume and carbon dioxide injection pressure are obtained.

[0021] Based on the initial injection volume and the oxygen consumption, obtain the oxygen injection volume and oxygen injection pressure;

[0022] The actual injection parameters are determined based on the initial injection volume, the carbon dioxide injection volume, and the oxygen injection volume.

[0023] Based on the actual injection parameters, carbon dioxide, oxygen, and liquid are injected into the injection well;

[0024] The actual injection parameters include the actual oxygen injection volume, actual oxygen injection pressure, actual carbon dioxide injection volume, actual carbon dioxide injection pressure, actual liquid injection volume, and actual liquid injection pressure.

[0025] Optionally, the high-pressure leaching system further includes a pumping device, a pumping well and a pumping pipeline, a submersible pump installed in the pumping well, one end of the pumping pipeline connected to the submersible pump, and the other end of the pumping pipeline connected to a hydrometallurgical plant, with a pumping flow meter and a sampling port sequentially installed on the pumping pipeline. The high-pressure leaching method further includes the following steps:

[0026] Based on the actual injection volume, formation pressure, and submersible pump parameters of the injection well, the pumping flow rate of the extraction well is obtained;

[0027] Based on the pumping flow rate and the actual injection flow rate of the injection well, the pumping device is started;

[0028] A liquid sample is collected through the sampling port, the sampling parameters in the liquid sample are analyzed, and the sampling parameters are compared with the original parameters in the groundwater to determine whether there is residual oxygen.

[0029] If there is no residual oxygen or the residual oxygen content is too low, continue to inject oxygen at a rate greater than or equal to the actual oxygen injection amount. If the residual oxygen reaches the set value, reduce the actual oxygen injection amount.

[0030] Based on the extracted liquid sample, the amount of carbon dioxide injected is adjusted.

[0031] Optionally, the initial injection volume Q:

[0032]

[0033] In the formula, K is the formation permeability; h is the ore body thickness; Δp is the rise in formation pressure during high-pressure injection; μ is the viscosity of the injected fluid; C is a coefficient related to the compressibility of the formation; and t is the injection duration, which changes with the injection duration, resulting in changes in formation pressure and injection flow rate.

[0034] The injection pressure p represents the pressure displayed on the high-pressure gauge of the high-pressure injection pump during injection.

[0035] Δp = p - p1;

[0036] pw=Δp+p i p w <p f ;

[0037] In the formula, p1 is the pipe loss pressure; p i p represents the original formation pressure. w p represents the formation pressure at the bottom of the well. f The formation fracturing pressure, p during the injection process w <p f .

[0038] Optionally, the carbon dioxide injection amount includes the gas injection amount of low-pressure injected carbon dioxide gas and the liquid injection amount of high-pressure injected liquid carbon dioxide.

[0039] The high-pressure leaching system and method based on carbon dioxide and oxygen provided in this invention embodiment include a carbon dioxide injection device, a high-pressure oxygen injection device, and a high-pressure liquid injection device. The carbon dioxide injection device is connected to a liquid injection pipeline via a carbon dioxide gas delivery pipeline, and a liquid carbon dioxide delivery pipeline is connected to an injection well. One end of the liquid injection pipeline is connected to a water storage tank, and the other end of the liquid injection pipeline is connected to the injection well. The other ends of the carbon dioxide gas delivery pipeline and the liquid carbon dioxide delivery pipeline are connected to a liquid carbon dioxide storage tank. The high-pressure oxygen injection device includes a high-pressure oxygen delivery pipeline, one end of which is connected to a liquid oxygen storage tank, and the other end of which is connected to the injection well. The high-pressure injection device can increase formation pressure, enhance formation energy, increase groundwater flow velocity and mass transfer efficiency, improve the seepage field of low-permeability sandstone uranium ore layers, and improve the effect of in-situ leaching of uranium. Carbon dioxide can enter the injection well in both low-pressure and high-pressure forms, which can not only meet the carbon dioxide injection requirements of conventional in-situ leaching of uranium, but also be injected into the ore-bearing layer in a high-pressure liquid form, increasing the concentration of carbon dioxide in the groundwater, increasing the acidity of the groundwater, accelerating the chemical reaction rate of carbonate mineral dissolution, and improving the limited complexation efficiency of carbonate, thereby improving the uranium leaching efficiency. Oxygen enters the injection well in a high-pressure form, which can increase the solubility of oxygen in the injection fluid, thereby forming a high-concentration oxygen-containing solution in the injection fluid, which can rapidly oxidize uranium-bearing minerals and reducing substances, and improve the uranium leaching efficiency.

[0040] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of a high-pressure leaching system according to an embodiment of the present invention.

[0043] in, Figure 1 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0044] 100 High-pressure leaching system, 101 Liquid carbon dioxide storage tank, 102 Low-pressure valve, 103 First air-bath vaporizer, 104 First electrically heated vaporizer, 105 Gas flow regulating valve, 106 Carbon dioxide gas pressure gauge, 107 First gas mass flow meter, 108 Carbon dioxide gas delivery pipeline, 109 Check valve, 110 Gas-liquid mixer, 111 High-pressure valve, 112 First high-pressure cryogenic liquid pump, 113 Liquid carbon dioxide delivery pipeline, 114 Liquid pressure gauge, 115 High-pressure flow meter, 116 First high-pressure check valve, 117 Liquid oxygen storage tank, 118 Second high-pressure cryogenic liquid pump, 119 Second air-bath vaporizer, 120 Second electrically heated vaporizer, 121 High-pressure oxygen buffer tank group, 122 123 Oxygen pressure gauge, 124 Second gas mass flow meter, 125 Second high-pressure check valve, 126 High-pressure oxygen delivery pipeline, 127 Water storage tank, 128 Centrifugal pump, 129 Liquid injection flow meter, 130 Low-pressure pressure gauge, 131 High-pressure injection pump, 132 High-pressure pressure gauge, 133 Liquid injection pipeline, 134 Third high-pressure check valve, 135 Liquid injection valve, 136 Oxygen valve, 137 High-pressure safety valve, 138 Wellhead sealing device, 149 High-pressure gas-liquid mixer, 140 Injection well, 141 Injection well seepage filter, 142 Ore-bearing aquifer, 143 Extraction well seepage filter, 144 Extraction well, 145 Submersible pump, 146 Liquid extraction pipeline, 147 Liquid extraction flow meter, 148 Sampling port, 149 Hydrometallurgical plant. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Before providing a further detailed description of the embodiments of the present invention, the directional terms used in the embodiments of the present invention, such as "upper part", "lower part" and "side part", are not intended to limit the scope of protection of the present invention.

[0047] To make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0048] like Figure 1As shown, one embodiment of the present invention provides a high-pressure leaching system 100 based on carbon dioxide and oxygen, including a liquid carbon dioxide storage tank 101 and a liquid oxygen storage tank 117. The high-pressure leaching system 100 further includes: a carbon dioxide injection device, a high-pressure oxygen injection device, and a high-pressure liquid injection device. The carbon dioxide injection device includes a carbon dioxide gas delivery pipeline 108 and a liquid carbon dioxide delivery pipeline 113. The high-pressure liquid injection device includes an injection pipeline 132, one end of which is connected to a water storage tank 126, and the other end of which is connected to an injection well 139. The device is equipped with a gas-liquid mixer 110, one end of a carbon dioxide gas delivery pipeline 108 is connected to a liquid carbon dioxide storage tank 101, and the other end of the carbon dioxide gas delivery pipeline 108 is connected to the gas-liquid mixer 110. One end of a liquid carbon dioxide delivery pipeline 113 is connected to the liquid carbon dioxide storage tank 101, and the other end of the liquid carbon dioxide delivery pipeline 113 is connected to an injection well 139. The high-pressure oxygen injection device includes a high-pressure oxygen delivery pipeline 125, one end of which is connected to a liquid oxygen storage tank 117, and the other end of which is connected to an injection well 139.

[0049] The high-pressure leaching system 100 includes a carbon dioxide injection device, a high-pressure oxygen injection device, and a high-pressure liquid injection device. The carbon dioxide injection device is connected to the liquid injection device via a carbon dioxide gas delivery pipeline 108 and a liquid carbon dioxide delivery pipeline 113, which is connected to the injection well 139. One end of the liquid injection pipeline 132 is connected to a water storage tank 126, and the other end of the liquid injection pipeline 132 is connected to the injection well 139. The other ends of the carbon dioxide gas delivery pipeline 108 and the liquid carbon dioxide delivery pipeline 113 are connected to a liquid carbon dioxide storage tank 101. The high-pressure oxygen injection device includes a high-pressure oxygen delivery pipeline 125, one end of which is connected to a liquid oxygen storage tank 117, and the other end of which is connected to the injection well 139. The high-pressure injection device increases formation pressure, enhances formation energy, improves groundwater flow velocity and mass transfer efficiency, improves the seepage field of low-permeability sandstone uranium ore layers, and enhances the effectiveness of in-situ leaching of uranium. Carbon dioxide can enter injection well 139 in both low-pressure and high-pressure forms, not only meeting the carbon dioxide injection requirements of conventional in-situ leaching of uranium but also being injected into the ore-bearing layer in a high-pressure liquid form. This increases the concentration of carbon dioxide in groundwater, increases groundwater acidity, accelerates the chemical reaction rate of carbonate mineral dissolution, and simultaneously improves the limited complexation efficiency of carbonate, thereby enhancing uranium leaching efficiency. Oxygen enters injection well 139 in a high-pressure form, increasing the solubility of oxygen in the injection fluid, thus forming a high-concentration oxygen-containing solution in the injection fluid. This solution can rapidly oxidize uranium-bearing minerals and reducing substances, improving uranium leaching efficiency.

[0050] In one feasible embodiment, the carbon dioxide injection device further includes: a low-pressure valve 102, a first air bath vaporizer 103, a first electrically heated vaporizer 104, a gas flow regulating valve 105, a carbon dioxide gas pressure gauge 106, a first gas mass flow meter 108, and a check valve 109, which are sequentially arranged on the carbon dioxide gas delivery pipeline 108. The low-pressure valve 102 is located at one end of the carbon dioxide gas delivery pipeline 108 near the liquid carbon dioxide storage tank 101, and the check valve 109 is located at one end of the carbon dioxide gas delivery pipeline 108 near the gas-liquid mixer 110.

[0051] The liquid carbon dioxide delivery pipeline 113 is sequentially equipped with a high-pressure valve 111, a first high-pressure cryogenic liquid pump 112, a liquid pressure gauge 114, a high-pressure flow meter 115, and a first high-pressure check valve 116. The high-pressure valve 111 is located at one end of the liquid carbon dioxide delivery pipeline 113 near the liquid carbon dioxide storage tank 101.

[0052] The liquid carbon dioxide storage tank 101 is used to store cryogenic liquid carbon dioxide; the low-pressure valve 102 is used to control the flow of liquid carbon dioxide from the liquid carbon dioxide storage tank 101 to the low-pressure side pipeline (carbon dioxide gas transmission pipeline 108); the first air-bath vaporizer 103 converts cryogenic liquid carbon dioxide into cryogenic gaseous carbon dioxide; the first electric heating vaporizer 104 heats the cryogenic gaseous carbon dioxide to the required temperature. The temperature of the heated gaseous carbon dioxide is generally between 0℃ and 20℃. The liquid carbon dioxide in the liquid carbon dioxide storage tank 101 is usually below -20℃. To avoid pipeline freezing and icing, the liquid carbon dioxide needs to be heated. Generally, in summer, only the first air-bath vaporizer 103 needs to be turned on to achieve the required heating temperature. In winter, both the first air-bath vaporizer 103 and the first electric heating vaporizer 104 need to be turned on simultaneously. The temperature of the gaseous carbon dioxide meets the requirements, thus preventing pipeline icing and extending pipeline lifespan; the gas flow regulating valve 105 controls the flow rate of carbon dioxide gas; the carbon dioxide gas pressure gauge 106 monitors the delivery pressure of carbon dioxide gas; the first gas mass flow meter 107 measures the amount of carbon dioxide gas injected; the check valve 109 is installed on the carbon dioxide gas delivery pipeline to prevent the injected liquid (water) from flowing back into the carbon dioxide gas delivery pipeline 108 when the injection pressure (high-pressure injection device) is higher than the gaseous carbon dioxide injection pressure, thus protecting the safety of the carbon dioxide injection device; the gas-liquid mixer 110 is installed at the junction of the carbon dioxide gas delivery pipeline 108 and the injection pipeline 132 to fully mix and dissolve the carbon dioxide gas with the injected liquid (water), typically with a carbon dioxide gas delivery pressure not exceeding 2 MPa. Understandably, when transporting carbon dioxide gas at low pressure, a very high pressure is not required, because the pressure of the pipe flowing out of the water storage tank 126 is generally less than 2 MPa. The pressure of the carbon dioxide gas can be slightly higher than the pipe pressure at the point where it comes out of the water storage tank 126, so that the carbon dioxide gas can be transported to the gas-liquid mixer 110. After mixing, the liquid enters the high-pressure injection pump 130 for pressurization and then enters the injection well 139. The pressure of the liquid carbon dioxide after passing through the high-pressure injection pump 130 can reach 25 MPa.

[0053] Furthermore, if high-pressure injection of liquid carbon dioxide is required, the liquid carbon dioxide can be pressurized to the required pressure by the first high-pressure cryogenic liquid pump 112 and then directly injected into the injection well 139, with a maximum pressure of 25 MPa. The high-pressure valve 111 is used to control the flow of liquid carbon dioxide from the liquid carbon dioxide storage tank 101 into the high-pressure side pipeline (liquid carbon dioxide delivery pipeline 113). The first high-pressure cryogenic liquid pump 112 draws cryogenic liquid carbon dioxide from the liquid carbon dioxide storage tank 101 and pressurizes it to a high-pressure state. At this high-pressure state, the carbon dioxide enters the injection well 139 directly in liquid form, and the pressure is higher than that of the liquid carbon dioxide storage tank 101. The pressure (2.2MPa) after passing through the first high-pressure cryogenic liquid pump 112 can reach a maximum pressure of 25MPa. The specific high-pressure state after pressurization can be determined according to the formation pressure and the amount of liquid carbon dioxide to be injected. The liquid pressure gauge 114 is used to monitor the delivery pressure of liquid carbon dioxide. The high-pressure flow meter 115 is used to measure the injection volume of liquid carbon dioxide. The first high-pressure check valve 116 is installed on the liquid carbon dioxide delivery pipeline 113 to prevent the injected liquid (water) from flowing back into the liquid carbon dioxide delivery pipeline 113 when the injection pressure (high-pressure injection device) is higher than the liquid carbon dioxide injection pressure. In other words, it can protect the safety of the carbon dioxide injection device.

[0054] It should be noted that both the carbon dioxide gas delivery pipeline 108 and the liquid carbon dioxide delivery pipeline 113 are made of high-pressure resistant seamless stainless steel pipes. For low-permeability, difficult-to-inject, and difficult-to-extract mineral-bearing layers, the injection pressure is low and the flow rate is small, resulting in insufficient carbon dioxide and oxygen content, leading to poor dissolution and oxidation performance and failing to achieve the desired leaching effect. In this case, high-pressure injection of liquid carbon dioxide is required, as injecting a large amount of carbon dioxide can quickly improve the leaching effect. When the pH, carbonate, and bicarbonate levels in the leachate meet the leaching requirements, high-pressure injection of liquid carbon dioxide is no longer necessary; instead, low-pressure injection of carbon dioxide gas can be used to maintain the carbonate concentration in the groundwater to meet the leaching effect. If the leaching effect deteriorates again, the injection method can be readjusted, i.e., high-pressure injection of liquid carbon dioxide can be resumed.

[0055] Carbon dioxide can be injected into injection well 139 in both low-pressure and high-pressure forms. This not only meets the carbon dioxide injection requirements of conventional uranium leaching but also allows for high-pressure liquid injection into the ore body 142 of the ore-bearing aquifer 141. This significantly increases the concentration of carbon dioxide in the groundwater, increases its acidity, accelerates the chemical reaction rate of carbonate mineral dissolution, and improves uranyl carbonate complexation efficiency, thereby enhancing uranium leaching efficiency. It should be noted that gaseous carbon dioxide must be mixed with water to dissolve before entering injection well 139. It cannot enter directly in gaseous form, as this would hinder its entry and cause blockage of the ore-bearing layer. When liquid carbon dioxide is injected directly into injection well 139, its liquid nature facilitates entry, and it does not need to be injected simultaneously with water. Injecting liquid carbon dioxide first, followed by water, displaces the carbon dioxide to deeper layers of the ore-bearing layer, aiding in the dissolution of the ore-bearing rocks.

[0056] In one feasible embodiment, the high-pressure oxygen injection device further includes a second high-pressure cryogenic liquid pump 118, a second air-bath vaporizer 119, a second electrically heated vaporizer 120, a high-pressure oxygen buffer tank group 121, an oxygen pressure gauge 122, a second gas mass flow meter 123, a second high-pressure check valve 124, and an oxygen valve 135, which are sequentially arranged on the high-pressure oxygen delivery pipeline 125, with the oxygen valve 135 located at one end of the high-pressure oxygen delivery pipeline 125 near the injection well 139.

[0057] The system includes a liquid oxygen storage tank 117 for storing cryogenic liquid oxygen; a second high-pressure cryogenic liquid pump 118 extracts cryogenic liquid oxygen from the liquid oxygen storage tank 117 and pressurizes it to a high-pressure state. The pressure of the liquid oxygen storage tank 117 is generally below 1 MPa, while the injection pressure is generally around 2 MPa. To allow oxygen to enter the injection well 139, the oxygen must be pressurized. After vaporization, the liquid oxygen directly enters the injection well 139, while water is being injected at the wellhead simultaneously. Therefore, the oxygen injection pressure must be greater than the liquid injection pressure to allow oxygen to enter the injection well. The oxygen injection pressure is between 2 MPa and 25 MPa, slightly higher than the liquid injection pressure, with a maximum pressure of 25 MPa. A second air-bath vaporizer 119 converts cryogenic liquid oxygen into cryogenic gaseous oxygen. A second electrically heated vaporizer 120 converts the cryogenic gaseous oxygen... Heating to the required temperature, above freezing, is sufficient to prevent pipe freezing. The principle is the same as that of the first air-bath vaporizer 103 and the first electric-heated vaporizer 104, and will not be repeated here. The high-pressure oxygen buffer tank group 121 is used to buffer oxygen and maintain a high-pressure state. The oxygen pressure gauge 122 is used to monitor the oxygen injection pressure. The second gas mass flow meter 123 is used to measure the amount of oxygen injected. The second high-pressure check valve 124 is installed at the end of the high-pressure oxygen delivery pipeline 125 near the injection well 139 to prevent backflow of the injected liquid (water) into the high-pressure oxygen delivery pipeline 125 when the injection pressure (high-pressure injection device) is higher than the oxygen injection pressure, thus protecting the safety of the high-pressure oxygen injection device. The oxygen valve 135 is used to open or close the flow of oxygen from the high-pressure oxygen delivery pipeline 125 into the injection well 139. Similarly, the high-pressure oxygen delivery pipeline 125 uses high-pressure resistant seamless stainless steel pipe.

[0058] It should be noted that oxygen is injected into injection well 139 under high pressure, which greatly increases the solubility of oxygen in the injected solution, thus forming a high-concentration oxygen-containing solution in subsequent injections. The high-pressure gas-liquid mixer 138 thoroughly mixes the injected gas and liquid, allowing the high-oxygen-containing solution to be injected into injection well 139. This rapidly oxidizes uranium-bearing minerals and reducing agents, improving uranium leaching efficiency. Understandably, after tetravalent uranium in uranium-bearing minerals is oxidized to hexavalent uranium, it is more easily complexed with carbonate and dissolved in the solution. Reducing agents, such as pyrite, organic matter, and coal, also consume oxygen. Therefore, the high-concentration oxygen-containing solution can meet the oxidation requirements of these substances, ensuring that the uranium-bearing minerals are also over-oxidized, thus improving the leaching effect.

[0059] In one feasible embodiment, the high-pressure injection device further includes: a centrifugal pump 127, an injection flow meter 128, a low-pressure gauge 129, a gas-liquid mixer 110, a high-pressure injection pump 130, a high-pressure gauge 131, a third high-pressure check valve 133, and an injection valve 134, which are sequentially arranged on the injection pipeline 132. The injection valve 134 is located at one end of the injection pipeline 132 near the injection well 139.

[0060] The system includes a water storage tank 126 for storing groundwater and providing a water source for the high-pressure injection device; a centrifugal pump 127 for pumping the groundwater from the storage tank 126 into the injection pipeline 132 and maintaining a certain delivery pressure; an injection flow meter 128 for measuring the injection volume; a low-pressure gauge 129 for monitoring the pressure of the groundwater delivered by the centrifugal pump 127; and a high-pressure injection pump 130 for pressurizing the groundwater delivered by the centrifugal pump 127 to a high-pressure state (2MPa to 25MPa), with a maximum pressure of 25MPa. The high-pressure state is related to the formation pressure and the injection volume, and the actual injection volume is related to the formation pressure. The higher the formation pressure, the smaller the actual injection volume. To increase the injection volume, the injection pressure of the high-pressure injection pump 130 must be increased, generally between 2MPa and 25MPa. The high-pressure gauge 131 is used to monitor the injection pressure. The injection pipeline 132 is made of high-pressure resistant and corrosion-resistant steel pipe. The third high-pressure check valve 133 is installed at the end of the injection pipeline 132 near the injection well 139 to prevent fluid in the injection well 139 from flowing back into the injection pipeline 132 and to protect the safety of the high-pressure injection device. The injection valve 134 is used to open or close the flow of fluid in the injection pipeline 132 into the injection well 139.

[0061] It should be noted that the injection method of the high-pressure injection device can increase the formation pressure, enhance the formation energy, increase the groundwater flow velocity and mass transfer efficiency, improve the seepage field of low-permeability sandstone uranium ore layers, and improve the effect of in-situ leaching uranium mining.

[0062] In one feasible implementation, the high-pressure leaching system 100 further includes:

[0063] The high-pressure gas-liquid mixer 138, the end of the liquid injection pipeline 132 away from the water storage tank 126 and the end of the high-pressure oxygen delivery pipeline 125 away from the liquid oxygen storage tank 117 are both connected to the high-pressure gas-liquid mixer 138, and a high-pressure safety valve 136 is provided on the high-pressure gas-liquid mixer 138.

[0064] A wellhead sealing device 137 is provided at the opening end of the injection well 139. At least part of the high-pressure gas-liquid mixer 138 passes through the wellhead sealing device 137 and is installed in the injection well 139. An injection seepage filter 140 is provided on the injection well 139. The injection seepage filter 140 is located in the ore body 142, which is located in the ore-bearing aquifer 141.

[0065] Due to gas solubility issues, gas overflowing from the injection fluid accumulates at the top of injection well 139, causing pressure increases within injection well 139. When the pressure in injection well 139 exceeds the safety pressure, high-pressure safety valve 136 is used to relieve pressure and maintain the safe state of injection well 139. Wellhead sealing device 139 is a high-pressure resistant threaded device with sealing function. A wellhead sealing device 137 is installed at the wellhead of both injection well 139 and extraction well 144 to maintain a sealed state within both wells. High-pressure gas-liquid mixer 138 is located inside the injection well 139 shaft below wellhead sealing device 137 to fully mix the high-pressure injected gas and liquid, ensuring the gas is fully dissolved and mixed with the injection fluid (groundwater) before being injected into injection well 139. High-pressure oxygen injection and high-pressure liquid injection (carbon dioxide) are mixed in high-pressure gas-liquid mixer 138 to form an oxygen-rich solution, which then enters injection well 139.

[0066] It should be noted that the injection well 139 is a fluid channel from the surface to the ore-bearing stratum, and is formed by high-pressure resistant well casing and high-strength cement and stratum consolidation; the injection seepage filter 140 is a fluid channel connecting the injection well 139 and the ore-bearing aquifer 141, and is mainly set in the stratum section where the ore body 142 is located; the ore body 142 is located in the ore-bearing aquifer 141.

[0067] In one feasible embodiment, the high-pressure leaching system 100 further includes a liquid extraction device, which comprises:

[0068] The extraction well 144 is equipped with an extraction seepage filter 143, which is located inside the ore body 142. The wellhead of the extraction well 144 is equipped with a wellhead device, and a submersible pump 145 is installed inside the extraction well 144.

[0069] The liquid extraction pipeline 146 is connected to a submersible pump 145 at one end and to a hydrometallurgical plant 149 at the other end. A liquid extraction flow meter 147 and a sampling port 148 are sequentially installed on the liquid extraction pipeline 146.

[0070] The submersible pump 145 lifts the leachate (fluid passing through the ore body) from the extraction well 144 to the surface. The power, head, and flow rate of the submersible pump 145 need to be selected according to the extraction volume, groundwater level, etc. A flow meter 147 and a sampling port 148 are installed on the extraction pipeline 146. The flow meter 147 is used to measure the flow rate of the leachate, and the sampling port 148 is used to collect leachate samples for subsequent analysis in order to adjust the flow rate and pressure of each device.

[0071] It should be noted that the extraction seepage filter 143 is a fluid channel connecting the ore-bearing aquifer 141 and the extraction well 144, and is mainly installed in the stratum section where the ore body 142 is located; the extraction well 144 is a fluid channel from the ore-bearing stratum to the surface. The wellhead device of the extraction well 144 serves to fix the submersible pump 145.

[0072] Furthermore, under high-pressure injection conditions, the solubility of carbon dioxide and oxygen increases with increasing pressure. High-pressure injection of gaseous or liquid carbon dioxide increases the acidity of groundwater, accelerating mineral dissolution and uranium complexation. High-pressure injection of oxygen rapidly oxidizes uranium-bearing minerals and reducing agents, improving uranium leaching efficiency. The use of high-pressure injection (using a high-pressure injection device), oxygen injection (using a high-pressure oxygen injection device), and carbon dioxide injection (using a carbon dioxide injection device) significantly enhances the synergistic effect of these three processes. Groundwater seepage rate, oxidation effect, and chemical dissolution rate will all increase rapidly, achieving a synergistic physical-chemical leaching effect. This application provides a new mining method for sandstone uranium mines with low permeability, difficult injection and extraction, and poor leaching efficiency, enabling the extraction of many previously untapped uranium resources and improving uranium metal recovery. It is understandable that high-pressure carbon dioxide injection helps improve the synergistic effect of uranium leaching, while low-pressure carbon dioxide injection (a mixture of gaseous and water-based carbon dioxide) maintains the carbonate concentration in groundwater at the lowest possible level.

[0073] Another embodiment of the present invention provides a high-pressure leaching method based on carbon dioxide and oxygen. Utilizing the aforementioned high-pressure leaching system, the high-pressure leaching method includes the following steps:

[0074] Step 1: Based on formation parameters, obtain the initial injection volume and initial injection pressure of the high-pressure injection device;

[0075] Step 2: Based on the initial injection volume and the required carbon dioxide and oxygen consumption, obtain the carbon dioxide injection volume and carbon dioxide injection pressure.

[0076] Step 3: Based on the initial injection volume and the oxygen consumption, obtain the oxygen injection volume and oxygen injection pressure;

[0077] Step 4: Determine the actual injection parameters based on the initial injection volume, carbon dioxide injection volume, and oxygen injection volume;

[0078] Step 5: Based on the actual injection parameters, inject carbon dioxide, oxygen, and liquid into the injection well;

[0079] The actual injection parameters include the actual oxygen injection volume, actual oxygen injection pressure, actual carbon dioxide injection volume, actual carbon dioxide injection pressure, actual liquid injection volume, and actual liquid injection pressure.

[0080] In step 1, the initial injection volume is calculated based on parameters such as formation permeability coefficient and formation pressure. The initial injection pressure is related to formation permeability, formation water head pressure, and the initial injection volume. For example, if the preset initial injection volume is 1 m³, the initial injection pressure is calculated based on these parameters. 3 / h, then the initial injection pressure may be 1MPa, when the initial injection volume is 2m 3 If the injection rate is / h, the injection pressure may be 3MPa. The initial injection volume and pressure need to be determined through hydrogeological tests. Before the high-pressure injection leaching operation begins, parameters such as ore body thickness, formation permeability, formation compressibility, and original formation pressure are obtained through geophysical wells and hydrogeological tests to calculate the initial injection volume and pressure. The injection pressure can reach up to 25MPa.

[0081] The initial injection volume Q:

[0082]

[0083] In the formula, K is the formation permeability; h is the ore body thickness; Δp is the rise in formation pressure during high-pressure injection; μ is the viscosity of the injected fluid; C is a coefficient related to the compressibility of the formation; and t is the injection duration, which changes with the injection duration, resulting in variations in formation pressure and injection flow rate. All the above parameters were obtained through geophysical well surveys and hydrogeological tests (the accuracy of the acquisition methods is questionable).

[0084] Δp = p - p1;

[0085] p w =Δp+p i p w <p f ;

[0086] In the formula, p1 is the pipe loss pressure; p i p represents the original formation pressure. w p represents the formation pressure at the bottom of the well. f The formation fracturing pressure, p during the injection process w <p f Δp represents the pressure rise in the formation during high-pressure injection, which is the pressure applied to the formation after being pressurized by the high-pressure pump. Because of pressure loss in the pipeline, the injection pressure needs to be subtracted from the pipeline loss pressure to obtain Δp. This allows us to obtain the initial injection volume Q and the formation pressure p at the bottom of the well. w .

[0087] Here, the injection pressure 'p' represents the pressure displayed on the high-pressure gauge of the high-pressure injection pump during injection. The injection pressure, as shown by the high-pressure gauge 131 on the high-pressure injection pump 130, is variable, corresponding to different injection volumes. This pressure is generally observed to adjust the injection process. However, this pressure differs from the pressure exerted by the formation, and the actual injection volume is related to the formation pressure. The higher the formation pressure, the smaller the actual injection volume. To increase the injection volume, the injection pressure of the high-pressure injection pump 130 must be increased.

[0088] In step 2, the carbon dioxide injection volume and injection pressure are calculated based on preset initial injection volume, reagent consumption (carbon dioxide and oxygen consumption), and other parameters. Reagent consumption includes carbon dioxide and oxygen consumption. This parameter is related to the mineral composition and content in the ore, such as carbonate minerals, reducing minerals, and organic matter. Carbon dioxide consumption can be obtained through laboratory leaching simulation experiments.

[0089] It should be noted that carbon dioxide consumption refers to the figure obtained in laboratory leaching simulation experiments. This figure is related to the mineral composition and content in the ore, such as carbonate minerals. It considers the carbon dioxide consumption under the condition that all mineral components participate in the reaction, and can estimate the total carbon dioxide consumption of the entire ore-bearing layer. When using low-pressure carbon dioxide injection, it is necessary to consider the different injection volumes at different pressures and the different solubility of carbon dioxide. Therefore, the solubility of carbon dioxide at that pressure must be calculated based on the injection volume to determine the amount of carbon dioxide injected. After a long period of carbon dioxide injection, the cumulative amount must reach the total carbon dioxide consumption for the ore-bearing layer to fully react and achieve the desired leaching effect. When using high-pressure carbon dioxide injection, the injected volume can be compared with the total carbon dioxide consumption, allowing for a one-time injection downhole to quickly reach the required amount of carbon dioxide for the entire ore-bearing layer, thus rapidly achieving the desired leaching effect.

[0090] There are two methods for calculating the amount of carbon dioxide injected: one is low-pressure injection of carbon dioxide gas, and the other is high-pressure injection of carbon dioxide liquid.

[0091] Specifically, the liquid carbon dioxide in the liquid carbon dioxide storage tank is converted into a gaseous state by the first air-bath vaporizer. This gas is then mixed with the injection liquid (groundwater) in the injection pipeline before being injected into the well. First, the solubility of the carbon dioxide gas is determined, and then the injection volume of carbon dioxide gas is calculated based on the injection volume.

[0092] S1 = k·f(P1-P2)·f(T1)

[0093] In the formula, S1 is the solubility of carbon dioxide gas; P1 is the carbon dioxide injection pressure; P2 is the outlet pressure of the centrifugal pump; k1 is Henry's constant; T1 is the water temperature in the injection pipeline; P1 is the data read from the carbon dioxide gas pressure gauge 106 of the low-pressure carbon dioxide gas delivery pipeline 108; P2 is the data read from the low-pressure pressure gauge 129 after the water in the storage tank 126 is pumped out by the centrifugal pump 127. This water flow merges with the carbon dioxide gas in the gas-liquid mixer 110, dissolving the carbon dioxide gas in the water, and then enters the high-pressure injection pump 130, and then enters the injection well 139. At this time, the carbon dioxide injection pressure P1 must be higher than the pressure P2 that the centrifugal pump 127 pumps out of the water in the storage tank 126. P1-P2 is the partial pressure of carbon dioxide, which is used to calculate the solubility of carbon dioxide.

[0094] m1=Q·S2

[0095] In the formula, m1 is the carbon dioxide gas injection volume; Q is the initial injection volume; and S2 is the concentration of carbon dioxide gas added to the injection solution. The concentration of carbon dioxide gas added to the injection solution is determined based on the carbon dioxide consumption obtained from laboratory leaching simulation experiments, and generally S2 ≤ S1. Since the initial injection volume Q is the volume of water injected over a certain period, for example, in meters... 3 / h, S2 is the concentration of carbon dioxide gas added to the injection solution, in kg / m³. 3 Therefore, the cumulative amount of m1 is the total amount of carbon dioxide gas injected. Thus, S2 cannot be completely random; provided it does not exceed the maximum solubility, the total amount of carbon dioxide gas injected must meet the total carbon dioxide consumption requirement of the entire ore-bearing layer mentioned above.

[0096] Furthermore, the liquid carbon dioxide in the storage tank is directly injected into the mine via a high-pressure pipeline (liquid carbon dioxide delivery pipeline) through a first high-pressure cryogenic liquid pump. The injection volume of liquid carbon dioxide is determined by the consumption of carbon dioxide by the ore body within the controlled ore area. The maximum injection pressure of liquid carbon dioxide can reach 25 MPa.

[0097] m2=M·C

[0098] In the formula, m2 represents the amount of liquid carbon dioxide injected; M represents the mass of the ore body within the controlled ore zone; and C represents the carbon dioxide consumption per unit mass, obtained from laboratory leaching simulation experiments. The carbon dioxide consumption figure here considers the total carbon dioxide consumption of the ore body throughout the entire ore-bearing layer. High-pressure injection of liquid carbon dioxide is not limited by gas solubility, allowing sufficient liquid carbon dioxide to be directly injected into the well to meet the requirements of leaching effectiveness.

[0099] In step 3, the oxygen injection volume is calculated based on the preset initial injection volume and oxygen consumption. Under high-pressure injection conditions, the dissolved oxygen content in groundwater is related to the formation pressure and groundwater temperature. When calculating the maximum dissolved oxygen content in the groundwater solution, the pressure is calculated based on the maximum bottom hole pressure, and the temperature is calculated based on the measured groundwater temperature.

[0100] S3=k·f(P w )·f(T2)

[0101] In the formula, S3 is the oxygen solubility; P w t is the formation pressure at the bottom of the well; k is a constant; T2 is the groundwater temperature.

[0102] m3=Q·S3

[0103] m4≤m3

[0104] In the formula, m3 is the dissolved oxygen volume; Q is the injection volume; and m4 is the oxygen injection volume.

[0105] It should be noted that the oxygen injection rate should generally not exceed the maximum dissolved oxygen content in the aqueous solution under formation pressure. Excess dissolved oxygen will escape from the groundwater and enter the formation pores as free oxygen bubbles, causing gas blockage and reducing formation permeability. All the above calculations are theoretical values. The oxygen injection rate here is calculated under a certain pressure, and the subsequent oxygen injection pressure is set based on this injection rate.

[0106] The injection pressures in the above steps were obtained by observing instruments during the experiment. In reality, the injection pressures of each part are different from the pressures in the experiment.

[0107] In step 4, based on the calculated initial injection volume, oxygen injection volume, and carbon dioxide injection volume, appropriate injection pressure and flow rate, oxygen injection pressure and flow rate, and carbon dioxide injection pressure and flow rate are determined. Measured values ​​are read using the high-pressure gauge 131 and injection flow meter 128 and verified against the calculated injection volume. The high-pressure injection pump 130 and centrifugal pump 127 are then adjusted to achieve suitable injection parameters. For oxygen injection, measured values ​​are read using the oxygen pressure gauge 122 and the second gas mass flow meter 123 and verified against the calculated oxygen injection volume. The second high-pressure cryogenic liquid pump 118 and high-pressure oxygen buffer tank 121 are then adjusted to achieve suitable oxygen injection parameters. The oxygen injection pressure should be greater than the injection pressure; the specific value should be adjusted according to the required oxygen injection volume. Carbon dioxide injection is performed by reading measured values ​​from pressure gauges (carbon dioxide gas pressure gauge 106 and liquid pressure gauge 114) and flow meters (first gas mass flow meter 107 and high-pressure flow meter 115). These values ​​are then compared with the calculated carbon dioxide injection volume. The first high-pressure cryogenic liquid pump 112, or the vaporizer and valves, are adjusted to achieve suitable carbon dioxide injection parameters. When injecting liquid carbon dioxide under high pressure, the first high-pressure cryogenic liquid pump 112 needs to be adjusted to adjust the liquid carbon dioxide injection parameters. When injecting carbon dioxide gas under low pressure, the air bath vaporizer (103), the electrically heated vaporizer (104), and the gas flow regulating valve (105) need to be adjusted to adjust the carbon dioxide gas injection parameters. When injecting according to the actual injection parameters, the experimental data may differ from the actual data. In this case, the above instruments can be adjusted to make the final injection parameters conform to the actual injection parameters.

[0108] In step 5, after determining the injection parameters, oxygen injection parameters, and carbon dioxide injection parameters in step 4, the high-pressure leaching system is started to inject the solution carrying oxygen and carbon dioxide into the injection well. The solution enters the ore-bearing aquifer through the injection seepage filter. During its migration into the formation, it continuously undergoes oxidation and dissolution reactions with uranium in the ore body, oxidizing the target element uranium from the tetravalent state to the hexavalent state and entering the groundwater to form a uranium-containing solution.

[0109] It should be noted that starting the high-pressure leaching system means that the above parameters were obtained through calculation and actual testing, and it has not yet officially entered operation. After all parameters are determined, the various valves of the carbon dioxide injection section, the high-pressure oxygen injection section, and the high-pressure liquid injection section are opened to begin actual operation. The various instruments are then adjusted to ensure that the parameters of the high-pressure leaching system match the calculated actual parameters.

[0110] In one feasible embodiment, the high-pressure leaching system further includes a pumping device, a pumping well and a pumping pipeline. A submersible pump is installed in the pumping well. One end of the pumping pipeline is connected to the submersible pump, and the other end is connected to a hydrometallurgical plant. A pumping flow meter and a sampling port are sequentially installed on the pumping pipeline. The high-pressure leaching method further includes the following steps:

[0111] Based on the actual injection flow rate, formation pressure, and submersible pump parameters of the injection well, the pumping flow rate of the extraction well is obtained;

[0112] Start the pumping device based on the pumping flow rate and the actual injection flow rate of the injection well.

[0113] Samples are collected through the sampling port, and the sampling parameters in the samples are analyzed. The sampling parameters are then compared with the original parameters in the groundwater to determine whether there is residual oxygen.

[0114] If there is no residual oxygen or the residual oxygen content is too low, continue to inject oxygen at a rate greater than or equal to the actual oxygen injection volume. If the residual oxygen reaches the set value, reduce the actual oxygen injection volume.

[0115] Adjust the carbon dioxide injection volume based on the extracted liquid sample.

[0116] Specifically, the pumping flow rate of the extraction well is determined based on parameters such as the actual injection flow rate of the injection well (which is essentially the flow rate from the storage tank; the amount of gas is relatively small and has little impact on the overall flow rate after mixing with water), formation pressure, and submersible pump capacity. Generally, the extraction and injection wells should maintain a balance, with the pumping flow rate being roughly the same as or greater than the injection flow rate. The specific pumping flow rate is determined by the required pressure difference between the extraction and injection wells. When a significant increase in pressure difference is needed, the injection flow rate is increased to raise the formation pressure around the injection well, while the submersible pump power is increased to raise the pumping flow rate and thus lower the formation pressure around the extraction well. Pressure difference is the driving force that propels groundwater from the injection well to the extraction well. Without pressure difference, the groundwater remains stagnant; the greater the pressure difference, the faster the groundwater flows. Therefore, to successfully extract groundwater, a greater pressure difference is required.

[0117] After determining the pumping parameters, the pumping device is started, forming a pumping-injection-leaching cycle between the extraction well and the injection well. Groundwater carrying uranium-containing solution enters the extraction well shaft from the mineralized aquifer through the extraction seepage filter, and is then pumped to the surface by a submersible pump and sent to a hydrometallurgical plant for treatment.

[0118] Samples were collected from the sampling port of the extraction pipeline. The oxygen content, pH, carbonate, and bicarbonate levels in the extracted liquid were analyzed and compared with those in the original groundwater to determine whether residual oxygen was present and whether the parameters met expectations. Based on the residual oxygen content in the sample, oxygen injection parameters were optimized. If there was no residual oxygen or the residual oxygen content was too low, oxygen injection continued according to the original parameters or the injection rate was increased. Once the residual oxygen content reached the expected value, the injection rate was reduced or high-pressure oxygen injection was stopped. Based on the pH, carbonate, and bicarbonate levels in the sample, carbon dioxide injection parameters were optimized. When pH, carbonate, and bicarbonate levels were low, the carbon dioxide injection rate was increased.

[0119] In other words, the high-pressure leaching system applied for first obtains relevant parameters through an experimental model, acquires actual injection parameters, starts the high-pressure leaching system based on the actual injection parameters, and adjusts various instruments based on the actual situation in the high-pressure leaching system to match the injection parameters in application with the calculated actual injection parameters. Then, the extraction flow rate is controlled according to the injection flow rate, and the extracted sample is tested. The injection parameters of the high-pressure oxygen injection device are adjusted according to the residual oxygen content in the extracted sample, and the injection parameters of the carbon dioxide injection device are adjusted according to the pH, carbonate, and bicarbonate content in the extracted sample.

[0120] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "a plurality" refers to two or more unless otherwise expressly defined.

[0121] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0122] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-pressure leaching system based on carbon dioxide and oxygen, comprising a liquid carbon dioxide storage tank and a liquid oxygen storage tank, characterized in that, The high-pressure leaching system further includes: a carbon dioxide injection device, a high-pressure oxygen injection device, and a high-pressure liquid injection device. The carbon dioxide injection device includes a carbon dioxide gas delivery pipeline and a liquid carbon dioxide delivery pipeline. The high-pressure liquid injection device includes an injection pipeline, one end of which is connected to a water storage tank, and the other end of which is connected to an injection well. A gas-liquid mixer is provided on the injection pipeline. One end of the carbon dioxide gas delivery pipeline is connected to the liquid carbon dioxide storage tank, and the other end of which is connected to the gas-liquid mixer. One end of the liquid carbon dioxide delivery pipeline is connected to the liquid carbon dioxide storage tank, and the other end of which is connected to the injection well. The high-pressure oxygen injection device includes a high-pressure oxygen delivery pipeline, one end of which is connected to the liquid oxygen storage tank, and the other end of which is connected to the injection well. The carbon dioxide injection device further includes: a low-pressure valve, a first air-bath vaporizer, a first electrically heated vaporizer, a gas flow regulating valve, a carbon dioxide gas pressure gauge, a first gas mass flow meter, and a check valve, which are sequentially arranged on the carbon dioxide gas delivery pipeline. The low-pressure valve is located at the end of the carbon dioxide gas delivery pipeline near the liquid carbon dioxide storage tank, and the check valve is located at the end of the carbon dioxide gas delivery pipeline near the gas-liquid mixer. The liquid carbon dioxide delivery pipeline is sequentially equipped with a high-pressure valve, a first high-pressure cryogenic liquid pump, a liquid pressure gauge, a high-pressure flow meter, and a first high-pressure check valve. The high-pressure valve is located at the end of the liquid carbon dioxide delivery pipeline near the liquid carbon dioxide storage tank. The high-pressure oxygen injection device also includes a second high-pressure cryogenic liquid pump, a second air-bath vaporizer, a second electric heating vaporizer, a high-pressure oxygen buffer tank group, an oxygen pressure gauge, a second gas mass flow meter, a second high-pressure check valve, and an oxygen valve, which are sequentially arranged on the high-pressure oxygen delivery pipeline. The oxygen valve is located at one end of the high-pressure oxygen delivery pipeline near the injection well. The high-pressure injection device further includes: a centrifugal pump, an injection flow meter, a low-pressure gauge, a gas-liquid mixer, a high-pressure injection pump, a high-pressure gauge, a third high-pressure check valve, and an injection valve, which are sequentially arranged on the injection pipeline. The injection valve is located at one end of the injection pipeline near the injection well.

2. The high-pressure leaching system based on carbon dioxide and oxygen according to claim 1, characterized in that, The high-pressure leaching system also includes: A high-pressure gas-liquid mixer is provided, wherein the end of the liquid injection pipeline away from the water storage tank and the end of the high-pressure oxygen delivery pipeline away from the liquid oxygen storage tank are both connected to the high-pressure gas-liquid mixer, and a high-pressure safety valve is provided on the high-pressure gas-liquid mixer; The injection well is provided with a wellhead sealing device at the open end. At least part of the high-pressure gas-liquid mixer is installed inside the injection well after passing through the wellhead sealing device. An injection seepage filter is provided on the injection well. The injection seepage filter is located in the ore body, which is located in the ore-bearing aquifer.

3. The high-pressure leaching system based on carbon dioxide and oxygen according to claim 2, characterized in that, The high-pressure leaching system further includes a liquid extraction device, which comprises: The extraction well is equipped with an extraction seepage filter located within the ore body. The wellhead of the extraction well is equipped with a wellhead device, and a submersible pump is installed inside the extraction well. The liquid extraction pipeline is connected to the submersible pump at one end and to the hydrometallurgical plant at the other end. A liquid extraction flow meter and a sampling port are sequentially installed on the liquid extraction pipeline.

4. A high-pressure leaching method based on carbon dioxide and oxygen, utilizing the high-pressure leaching system according to any one of claims 1 to 3, characterized in that, The high-pressure leaching method includes the following steps: Based on formation parameters, the initial injection volume and initial injection pressure of the high-pressure injection device are obtained; Based on the initial injection volume and the required carbon dioxide and oxygen consumption, the carbon dioxide injection volume and carbon dioxide injection pressure are obtained. Based on the initial injection volume and the oxygen consumption, obtain the oxygen injection volume and oxygen injection pressure; The actual injection parameters are determined based on the initial injection volume, the carbon dioxide injection volume, and the oxygen injection volume. Based on the actual injection parameters, carbon dioxide, oxygen, and liquid are injected into the injection well; The actual injection parameters include the actual oxygen injection volume, actual oxygen injection pressure, actual carbon dioxide injection volume, actual carbon dioxide injection pressure, actual liquid injection volume, and actual liquid injection pressure.

5. The high-pressure leaching method based on carbon dioxide and oxygen according to claim 4, characterized in that, The high-pressure leaching system further includes a pumping device, a pumping well, and a pumping pipeline. A submersible pump is installed in the pumping well. One end of the pumping pipeline is connected to the submersible pump, and the other end is connected to a hydrometallurgical plant. A flow meter and a sampling port are sequentially installed on the pumping pipeline. The high-pressure leaching method further includes the following steps: Based on the actual injection flow rate, formation pressure, and submersible pump parameters of the injection well, the pumping flow rate of the extraction well is obtained; Based on the pumping flow rate and the actual injection flow rate of the injection well, the pumping device is started; A liquid sample is collected through the sampling port, the sampling parameters in the liquid sample are analyzed, and the sampling parameters are compared with the original parameters in the groundwater to determine whether there is residual oxygen. If there is no residual oxygen or the residual oxygen content is too low, continue to inject oxygen at a rate greater than or equal to the actual oxygen injection amount. If the residual oxygen reaches the set value, reduce the actual oxygen injection amount. Based on the extracted liquid sample, the amount of carbon dioxide injected is adjusted.

6. The high-pressure leaching method based on carbon dioxide and oxygen according to claim 4, characterized in that, The initial injection volume Q: In the formula, K is the formation permeability; h is the ore body thickness; Δp is the rise in formation pressure during high-pressure injection; μ is the viscosity of the injected fluid; C is a coefficient related to the compressibility of the formation; and t is the injection duration, which changes with the injection duration, resulting in changes in formation pressure and injection flow rate. The injection pressure p represents the pressure displayed on the high-pressure gauge of the high-pressure injection pump during injection. Δp = p - p1; p w =Δp+p i ,p w <p f ; In the formula, p1 is the pipe loss pressure; p i p represents the original formation pressure. w p represents the formation pressure at the bottom of the well. f The formation fracturing pressure, p during the injection process w <p f .

7. The high-pressure leaching method based on carbon dioxide and oxygen according to claim 6, characterized in that, The carbon dioxide injection volume includes the gas injection volume of low-pressure injected carbon dioxide gas and the liquid injection volume of high-pressure injected liquid carbon dioxide.

Images