Method and device for catalytic leaching of argillaceous uranium ore based on ozone

Abstract

The application discloses a method and device for catalytic leaching of argillaceous uranium ore based on ozone, and relates to the technical field of uranium leaching and reaction equipment. The application utilizes biomass raw materials and iron-based material powder to prepare a magnetic composite material with catalysis-adsorption dual functions through in-situ reduction by high-temperature heat treatment. The slurry of argillaceous uranium ore and the magnetic composite material are mixed in a reactor for reaction. Ozone is introduced through an aeration disc to avoid bubble aggregation, significantly increase the gas-liquid contact area, and improve the ozone utilization rate. A spiral guide plate is arranged in the reactor to effectively prolong the gas-liquid contact time and improve the ozone mass transfer efficiency. A magnetic recovery device is used to recover the magnetic material to ensure the catalyst activity, reduce the catalyst loss rate, and realize efficient catalysis. Through optimization of the reactor structure, the catalyst preparation process and the process flow, the ozone utilization rate and the leaching efficiency of the argillaceous uranium ore are significantly improved, and the catalyst recycling and the recycling of residual gas are realized.

Description

Technical Field

[0001] This invention relates to the field of uranium leaching and reaction equipment technology, and more specifically, to a method and apparatus for ozone catalytic leaching of mudstone-type uranium ore. Background Technology

[0002] With the accelerated global energy transition, the demand for nuclear power, as a stable and reliable clean energy source, continues to grow, making the efficient development and utilization of uranium resources increasingly important. Mudstone-type uranium deposits in my country are characterized by large scale and low grade, often accompanied by organic matter. Their formation is mainly due to the enrichment of uranium in a reducing environment during sedimentary diagenesis. They are mainly distributed in Paleozoic-Mesozoic sedimentary basins in southern regions such as Hunan, Guangxi, and Yunnan. However, their poor permeability and high content of clay / gypsum / organic matter components make in-situ leaching technology difficult to apply. Furthermore, traditional heap leaching processes for uranium extraction from mudstone have revealed high acid consumption (80–150 kg / ton of ore), low leaching rates, and a tendency to cause acid pollution. Moreover, because uranium is closely associated with the clay components, the physicochemical processes of adsorption, encapsulation, and complexation make the separation of uranium from the ore body extremely difficult. Therefore, for the efficient mining of mudstone-type uranium resources, there is an urgent need to develop new leaching processes and equipment that are efficient, low-consumption, and environmentally friendly, in order to support the green development of such resources.

[0003] Therefore, there is an urgent need to design new uranium leaching processes and reactors to achieve efficient uranium leaching.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for ozone-catalytic leaching of mudstone-type uranium ore, which aims to significantly improve the uranium leaching rate while simultaneously increasing ozone utilization.

[0006] This invention is implemented as follows:

[0007] In a first aspect, the present invention provides a method for ozone-catalytic leaching of mudstone-type uranium deposits, comprising:

[0008] Biomass raw materials and iron-based material powders are mixed and treated at high temperature of 500℃-800℃ for 1 h-3 h. After cooling, they are separated by magnetic separation to obtain magnetic composite materials.

[0009] The mudstone-type uranium ore is crushed and slurried. The resulting slurry is mixed with magnetic composite materials and reacted. During the reaction, ozone is introduced into the reactor through an aeration disc. A spiral guide plate is installed in the reactor. After the reaction, the magnetic materials are recovered through a magnetic recovery device.

[0010] In an optional embodiment, during the preparation of the magnetic composite material, the mass ratio of biomass raw material to iron-based material powder is controlled to be (1-20):1;

[0011] And / or, the iron-based material powder is selected from at least one of hematite powder and magnetite powder;

[0012] And / or, the biomass raw material is selected from at least one of sugarcane bagasse, rice husk, sawdust and straw;

[0013] And / or, the high-temperature treatment is carried out under an inert atmosphere;

[0014] And / or, the biomass feedstock is dried and crushed before mixing.

[0015] In an optional embodiment, during the crushing and pulping process of mudstone-type uranium ore, the solid-liquid ratio of the slurry is controlled to be 1:(5-10).

[0016] And / or, adjust the pH of the slurry to 1.5-2.0 before mixing it with the magnetic composite material.

[0017] In an optional embodiment, the mass ratio of the amount of magnetic composite material added to the slurry is (1-5):100.

[0018] In an optional embodiment, the ozone concentration in the reactor is controlled at 50 mg / L-200 mg / L, and the ozone flow rate is 0.5 L / min-2.0 L / min;

[0019] And / or, the aeration disc is a microporous aeration disc with a pore size of 80 μm-120 μm;

[0020] And / or, ozone is generated using an ozone generator, delivered to the bottom of the reactor via an air pump and aerated through an aeration disc, and the ozone is returned to the ozone generator from the top of the reactor via a gas return pipeline.

[0021] In an optional embodiment, the reaction temperature is controlled at 30℃-60℃, and the magnetic material is recovered by a magnetic recovery device after 2 h-8 h of reaction.

[0022] And / or, the magnetic recovery device uses permanent magnets or electromagnets, and controls the magnetic field strength to be 0.5 T-2.0 T.

[0023] In an optional embodiment, the reactor is equipped with an external reflux pipeline, on which a radioactive detector is installed. The radioactive detector is used to detect the uranium concentration. When the concentration is lower than a set value, the slurry is refluxed back to the reactor through the control system to continue the reaction.

[0024] In an optional embodiment, the reactor has a cylindrical structure, with a spiral guide plate extending from the top to the bottom of the reactor. The pitch of the spiral guide plate is 100 mm to 300 mm, and the angle between the guide plate and the horizontal plane is 15° to 30°.

[0025] Secondly, the present invention provides an apparatus for implementing any of the methods described in the foregoing embodiments, comprising:

[0026] The reactor body has a spiral guide plate installed in its inner cavity and an aeration disc at the bottom.

[0027] The gas circulation unit includes an ozone generator, a gas pump, and a gas return pipeline. The outlet of the ozone generator is connected to the inlet of the gas pump, the outlet of the gas pump is connected to the bottom inlet of the reactor body, and the top outlet of the reactor body returns ozone to the ozone generator through the gas return pipeline.

[0028] The slurry treatment unit includes a slurry circulation pipeline with an inlet and an outlet. A magnetic recovery device and a radioactive detector are installed on the slurry circulation pipeline near the outlet.

[0029] In an optional implementation, electronic three-way valves are installed near the slurry outlet and inlet of the slurry circulation pipeline and connected to the control system.

[0030] This invention offers the following advantages: It utilizes biomass raw materials and iron-based material powders through in-situ reduction at high temperatures to produce a magnetic composite material with dual catalytic and adsorption functions. On one hand, this material provides numerous ozone adsorption sites through the increased specific surface area of ​​pyrolyzed biochar, thereby reducing ozone emission. On the other hand, the material decomposes and catalyzes the ozone adsorbed on the carbon material through its iron-based active sites, generating active species such as superoxide radicals and hydroxyl radicals, achieving efficient uranium leaching. Furthermore, after a single reaction, the material can be recovered using a magnetic recovery device for recycling. This invention mixes mudstone-type uranium ore slurry and the magnetic composite material in a reactor for reaction. Ozone is introduced using an aeration disc, preventing bubble aggregation and significantly increasing the gas-liquid contact area, thus improving ozone utilization. A spiral guide plate in the reactor effectively prolongs the gas-liquid contact time, improving ozone mass transfer efficiency. The magnetic recovery device ensures catalyst activity, reduces catalyst loss, and achieves highly efficient catalysis.

[0031] Furthermore, this invention offers the following advantages for mudstone-type uranium ore: Ozone, as a strong oxidant with a standard reduction potential of 2.07 V, can oxidize sparingly soluble U(IV) to easily soluble U(VI), demonstrating promising application prospects in uranium leaching. Compared to traditional oxidants, ozone's decomposition product is only oxygen, eliminating secondary pollution and exhibiting significant environmental friendliness. The novel process based on catalytic ozone activation under acidic conditions effectively reduces acid consumption in uranium leaching and minimizes the leaching of harmful metal ions. An intelligent circulation system composed of a radioactive detector, an electronic three-way valve, and a control system effectively enables multiple cyclic leaching of mudstone-type uranium ore, replacing traditional multi-stage acid leaching and effectively solving the problem of separating uranium from clay minerals, organic matter, and other muddy components in mudstone-type uranium ore. The prepared magnetic composite adsorption-catalysis bifunctional material significantly improves ozone utilization, thereby increasing the uranium leaching rate.

[0032] Therefore, this invention significantly improves ozone utilization and leaching efficiency of mudstone-type uranium ore by designing a novel reactor, preparing a novel catalyst, and developing a novel uranium leaching process. At the same time, it realizes the recycling of catalyst and the reuse of residual gas, and has the advantages of high processing efficiency, low operating cost, and environmental friendliness. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the device structure provided in an embodiment of the present invention;

[0035] Figure 2 The image shows the surface morphology of the magnetic composite material prepared in Example 1.

[0036] Explanation of main component symbols: 1-Reactor body; 2-Spiral guide plate; 3-Aeration disc; 4-Top air outlet; 5-Ozone generator; 6-Air pump; 7-Slurry inlet; 8-Slurry outlet; 9-Magnetic recovery device; 10-Radioactive detector; 11-Electronic three-way valve; 12-Bottom air inlet. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0038] To address the problems of low uranium leaching rate and low ozone utilization rate in existing technologies, this invention optimizes the uranium leaching device and process to significantly improve the uranium leaching rate and ozone utilization rate.

[0039] This invention provides a method for ozone-catalytic leaching of mudstone-type uranium ore, the steps of which are as follows:

[0040] S1. Preparation of magnetic composite materials

[0041] Biomass feedstock and iron-based material powder are mixed and treated at 500℃-800℃ for 1-3 hours. After cooling, the mixture is separated by magnetic separation to obtain a magnetic composite material. During the high-temperature treatment, the biomass undergoes pyrolysis and carbonization to form a porous carbon carrier. Simultaneously, iron-based oxides (such as Fe2O3) are reduced in situ to magnetite (Fe3O4) or zero-valent iron (Fe2O4), which have higher catalytic activity. 0 Nanoparticles, with their highly dispersed and firmly loaded active sites on a carbon matrix, are magnetically separated to remove unreacted biomass ash, non-magnetic impurities, or unloaded metal oxide aggregates, yielding a magnetic composite material. This magnetic composite material, prepared from biomass raw materials, achieves both waste resource utilization and excellent adsorption-catalysis dual functions, while being low-cost and environmentally friendly.

[0042] Specifically, the high-temperature treatment temperature can be 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, etc. The isothermal treatment time can be 1.0 h, 1.5 h, 2.0 h, 2.5 h, 3.0 h, etc. Magnetic separation can be carried out using existing magnetic separation equipment, such as permanent magnet drum separators or high-gradient electromagnetic separators. The high-temperature treatment can be carried out under an inert atmosphere, the type of inert atmosphere is not limited, such as nitrogen, argon, etc. The heating rate is not limited, such as 3-10°C / min, at which temperature is raised to 500℃-800℃.

[0043] It should be noted that iron-based materials (such as magnetite and hematite) exhibit excellent performance in catalyzing the decomposition of ozone to generate hydroxyl radicals. Their unique heterogeneous catalytic mechanism can effectively promote ozone decomposition and improve oxidation efficiency. However, traditional magnetic catalysts are prone to loss and are difficult to recover in slurry systems, leading to increased operating costs and potential secondary pollution from the leaching of heavy metal ions. This invention utilizes biomass materials as carriers or precursors to prepare magnetic composite materials. Biomass materials (such as straw, rice husks, and bagasse) are widely available and inexpensive, and their unique porous structure and surface functional groups provide ideal sites for the anchoring of metal ions. By combining biomass materials with iron-based materials through processes such as pyrolysis, both the resource utilization of waste biomass and the construction of highly efficient catalysts with magnetic separation properties can be achieved.

[0044] In some embodiments, the iron-based material powder is selected from at least one of hematite powder and magnetite powder. The iron-based material powder can be any one or more of the above. For example, the hematite powder can be a commercially available raw material, such as that purchased from Shanghai Maclean Company. The biomass raw material is selected from at least one of bagasse, rice husk, sawdust, and straw. The biomass raw material can be any one or more of the above. In the process of preparing the magnetic composite material, the mass ratio of biomass raw material to iron-based material powder is controlled to be (1-20):1, such as 1:1, 3:1, 5:1, 8:1, 10:1, 13:1, 15:1, 18:1, 20:1, etc.

[0045] In some embodiments, the biomass feedstock is dried and crushed before mixing, and the particle size after crushing is approximately 0.5 mm to 2.0 mm.

[0046] S2, Leaching

[0047] The apparatus used for leaching is referenced. Figure 1 The mudstone-type uranium ore is crushed and slurried. The resulting slurry is mixed with a magnetic composite material and reacted. During the reaction, ozone is introduced into the reactor through an aeration disc 3. A spiral guide plate 2 is installed in the reactor. After the reaction, the magnetic material is recovered through a magnetic recovery device 9. The method provided in this embodiment of the invention can be applied to, but is not limited to, other applications. Figure 1 Any apparatus capable of implementing this method is within the scope of protection of this invention. During the leaching process, the magnetic composite material effectively promotes ozone decomposition. Ozone molecules undergo electron transfer at active sites such as Fe(II) / Fe(III) on the catalyst surface, decomposing to produce highly oxidizing hydroxyl radicals (•OH) and superoxide radicals (O2). •- These free radicals can efficiently oxidize sparingly soluble tetravalent uranium (U+) in ores. 4+ ) is a soluble hexavalent uranyl ion (UO2) 2+ This improves oxidation efficiency.

[0048] It should be noted that by installing the spiral guide plate 2 inside the reactor, the gas-liquid contact time can be effectively extended, thereby improving the ozone mass transfer efficiency. The aeration disc 3 can generate uniform microbubbles, avoid bubble aggregation, significantly increase the gas-liquid contact area, and improve ozone utilization. The magnetic recovery device enables the recycling of the catalyst, reducing operating costs.

[0049] In some embodiments, mudstone-type uranium ore is crushed and mixed with water to form a slurry, with the solid-liquid mass ratio of the slurry controlled at 1:(5-10), such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc. To meet the pH requirements for leaching, the pH of the slurry is adjusted to 1.5-2.0 before being mixed with the magnetic composite material. Specifically, sulfuric acid solution, hydrochloric acid solution, or nitric acid solution can be used to adjust the pH value, which can be 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, etc. The mass ratio of the magnetic composite material to the slurry is (1-5):100, such as 1:100, 2:100, 3:100, 4:100, 5:100, etc.

[0050] Furthermore, this invention optimizes the ozone injection rate, controlling the ozone concentration in the reactor to be between 50 mg / L and 200 mg / L, such as 50 mg / L, 80 mg / L, 100 mg / L, 130 mg / L, 150 mg / L, 180 mg / L, 200 mg / L, etc. The ozone flow rate is between 0.5 L / min and 2.0 L / min, such as 0.5 L / min, 1.0 L / min, 1.5 L / min, 2.0 L / min, etc. The aeration disc 3 can be a microporous aeration disc with a pore size of 80 μm-120 μm, specifically pore sizes of 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, etc. The material of the microporous aeration disc can be porous ceramic, corundum, or other porous non-metallic materials.

[0051] like Figure 1As described above, ozone is generated by ozone generator 5 and transported to the bottom of the reactor by air pump 6, where it is aerated by aeration disc 3. The ozone is then returned to the ozone generator 5 from the top of the reactor via a gas return pipeline. This gas circulation system enables the reuse of unreacted ozone, reducing waste gas emissions and environmental pollution. The reactor has a cylindrical structure with a spiral guide plate 2 extending from the top to the bottom. The pitch of the spiral guide plate 2 is 100 mm-300 mm, such as 100 mm, 130 mm, 150 mm, 180 mm, 200 mm, 230 mm, 250 mm, 280 mm, 300 mm, etc.; the angle between the guide plate and the horizontal plane is 15°-30°, such as 15°, 18°, 20°, 23°, 25°, 28°, 30°, etc. The narrow, tall cylindrical reactor structure combined with the spiral guide plate effectively prolongs the gas-liquid contact time and improves the ozone mass transfer efficiency.

[0052] In some embodiments, the reaction temperature is controlled between 30℃ and 60℃ during the reaction process, such as 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, etc. After 2-8 hours of reaction, the magnetic material is recovered by the magnetic recovery device 9, and the reaction time can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, etc. The magnetic recovery device 9 can use a permanent magnet or an electromagnet, and the magnetic field strength is controlled between 0.5 T and 2.0 T, such as 0.5 T, 1.0 T, 1.5 T, 2.0 T, etc. The magnetic recovery device 9 enables the recycling of the catalyst and reduces operating costs.

[0053] In some embodiments, the reactor is equipped with an external reflux pipeline, on which a radioactive detector 10 is installed. The radioactive detector 10 detects the uranium concentration, and when the concentration falls below a set value, the slurry is refluxed back to the reactor by the control system to continue the reaction. The use of the radioactive detector 10 to detect the uranium concentration, in conjunction with an electronic three-way valve 11, enables intelligent circulation of the slurry, improving processing efficiency. Specifically, the radioactive detector 10 can be a commercially available gamma-ray detector with a detection limit of 0.01 μSf / h.

[0054] Figure 1 The apparatus shown in the embodiment of the present invention includes a reactor body 1, a gas circulation unit, and a slurry treatment unit. The following describes each part:

[0055] Reactor Body 1: A spiral guide plate 2 is installed inside the cavity of reactor body 1, which effectively prolongs the gas-liquid contact time. An aeration disc 3 is installed at the bottom of reactor body 1. After ozone passes through the aeration disc 3, it generates uniform microbubbles, preventing bubble aggregation and significantly increasing the gas-liquid contact area, thus improving ozone utilization. Specific parameters of the spiral guide plate 2 and aeration disc 3 can be found above.

[0056] Gas Circulation Unit: The gas circulation unit includes an ozone generator 5, a gas pump 6, and a gas return pipeline. The outlet of the ozone generator 5 is connected to the inlet of the gas pump 6, and the outlet of the gas pump 6 is connected to the bottom inlet 12 of the reactor body 1. The top outlet 4 of the reactor body 1 returns ozone to the ozone generator 5 through the gas return pipeline, thus realizing ozone circulation. The gas circulation unit enables the reuse of unreacted ozone, reduces waste gas emissions, and lowers environmental pollution.

[0057] The slurry treatment unit includes a slurry circulation pipeline with an inlet 7 and an outlet 8. A magnetic recovery device 9 and a radioactive detector 10 are installed near the outlet 8 on the slurry circulation pipeline. Electronic three-way valves 11 are installed near both the outlet 8 and the inlet 7 on the slurry circulation pipeline, and are connected to a control system. The radioactive detector 10 detects the uranium concentration at the outlet 8; if it falls below a set value, the slurry is circulated back to the reactor body 1 through the electronic three-way valve 11 to continue the reaction.

[0058] Experiments show that when typical uranium ores are treated using this invention, the uranium leaching rate can reach 88%-94%, the ozone utilization rate can be increased by more than 35%, and the magnetic material recovery rate can exceed 95%.

[0059] To achieve automated operation, a control system can be configured. Both the radioactive detector 10 and the electronic three-way valve 11 are connected to the control system. The signal detected by the radioactive detector 10 is transmitted to the control system. When the signal is lower than the set value, the slurry continues to circulate to the reactor body 1 for further reaction by adjusting the conduction path of the electronic three-way valve 11. When the concentration detected by the radioactive detector 10 is higher than the set value, the slurry is output through the slurry outlet 8 by adjusting the conduction path of the electronic three-way valve 11.

[0060] The control system may be an integrated circuit chip with signal processing capabilities. The aforementioned control system may be a general-purpose processor, including a central processing unit, digital signal processor, application-specific integrated circuit, field-programmable gate array or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, which can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor may be a microprocessor, and the control system provided in this embodiment may also be any conventional processor, etc.

[0061] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0062] The reaction apparatus used in the following embodiments is as follows: Figure 1 As shown, it includes reactor body 1, gas circulation unit and slurry treatment unit.

[0063] Reactor Body 1: The reactor body 1 adopts a narrow bottom area design with a diameter-to-height ratio of 1:5. It features an internal spiral guide plate 2 with a pitch of 200 mm and an angle of 20° with the horizontal plane. A fine-pore aeration disc 3 with a pore diameter of 100 μm, made of 316L stainless steel, is installed at the bottom.

[0064] Gas circulation unit: The gas circulation unit includes an ozone generator 5, a gas pump 6 and a gas return pipeline. The outlet of the ozone generator 5 is connected to the inlet of the gas pump 6. The outlet of the gas pump 6 is connected to the bottom inlet 12 of the reactor body 1. The top outlet 4 of the reactor body 1 returns ozone to the ozone generator 5 through the gas return pipeline.

[0065] The slurry treatment unit includes a slurry circulation pipeline with an inlet 7 and an outlet 8. A magnetic recovery device 9 (permanent magnet, magnetic field strength 1.0 T) and a radioactive detector 10 (gamma-ray detector, detection limit 0.01 μSf / h) are installed near the outlet 8 on the slurry circulation pipeline. Electronic three-way valves 11 are installed near both the outlet 8 and the inlet 7 on the slurry circulation pipeline. The radioactive detector 10 detects the uranium concentration at the outlet 8; if it falls below a set value, the uranium is circulated back to the reactor body 1 through the electronic three-way valves 11 to continue the reaction.

[0066] Example 1

[0067] This embodiment provides a method for ozone-catalytic leaching of mudstone-type uranium ore, the steps of which are as follows:

[0068] (1) Preparation of magnetic composite materials

[0069] Dry and crushed sugarcane bagasse was mixed with natural hematite powder at a mass ratio of 2:1. The mixture was heated to 600°C at a rate of 5°C / min under a nitrogen atmosphere and held at that temperature for 2 hours. After cooling, a magnetic composite material was obtained through magnetic separation. The surface morphology is as follows: Figure 2 As shown in the figure. Characterization shows that the material contains 58% magnetite and has a specific surface area of ​​53 m². 2 / g.

[0070] (2) Leaching

[0071] The test ore was taken from a mudstone-type uranium deposit in Qingyuan, Guangdong (uranium grade 0.045%). The ore was crushed to -200 mesh, and a slurry with a solid-liquid ratio of 1:5 was prepared and the pH was adjusted to 2.0. 3% magnetic composite material was added, and an ozone generator (ozone concentration 100 mg / L, gas flow rate 1.0 L / min) and gas pump were turned on. The reaction temperature was 40℃ and the reaction time was 4 hours.

[0072] After the reaction, the magnetic material is recovered using a magnetic recovery device with a recovery rate of 96%. A radioactive detector detects the uranium concentration at the slurry inlet. When the concentration is below 0.1 μSf / h, the slurry is circulated back to the reactor via an electronic three-way valve.

[0073] The test results showed that the uranium leaching rate reached 92%, the ozone utilization rate was 40% higher than that of the acid leaching method, and the catalyst recovery rate was 98%.

[0074] Example 2

[0075] This embodiment provides a method for ozone-catalytic leaching of mudstone-type uranium ore, the steps of which are as follows:

[0076] (1) Preparation of magnetic composite materials

[0077] Same as Example 1.

[0078] (2) Leaching

[0079] The test ore was taken from a sandy mudstone-type uranium deposit in Inner Mongolia (uranium grade 0.030%). The ore was crushed to -200 mesh, and a slurry with a solid-liquid ratio of 1:10 was prepared and the pH was adjusted to 2.0. 3% magnetic composite material was added, and an ozone generator was turned on (ozone concentration 5000 mg / L, gas flow rate 0.5 L / min). The reaction temperature was 30℃, and the reaction time was 2 hours.

[0080] After the reaction is complete, the magnetic material is recovered using a magnetic recovery device with a recovery rate of 95%. A radioactive detector detects the uranium concentration at the slurry inlet. When the concentration is below 0.1 μSf / h, the slurry is circulated back to the reactor via an electronic three-way valve.

[0081] The test results showed that the uranium leaching rate reached 88%, and the ozone utilization rate was 36% higher than that of the acid leaching method.

[0082] Example 3

[0083] The only difference from Example 1 is that a conventional reactor without baffles is used.

[0084] The results showed that in Example 1, the uranium leaching rate was 92% and the ozone consumption was 0.8 kg / t ore; in Example 3, the leaching rate was 78% and the ozone consumption was 1.2 kg / t ore. This indicates that the reactor structure of the present invention can significantly improve leaching efficiency and ozone utilization.

[0085] Example 4

[0086] This embodiment provides a method for ozone-catalytic leaching of mudstone-type uranium ore, the steps of which are as follows:

[0087] (1) Preparation of magnetic composite materials

[0088] Dry and crushed straw was mixed with magnetite powder at a mass ratio of 1:1, heated to 500°C at a rate of 5°C / min under a nitrogen atmosphere, held at the temperature for 3 hours, and then cooled before magnetic separation to obtain a magnetic composite material.

[0089] (2) Leaching

[0090] The test ore was taken from a mudstone-type uranium deposit in Qingyuan, Guangdong (uranium grade 0.045%). The ore was crushed to -200 mesh, and a slurry with a solid-liquid ratio of 1:5 was prepared and the pH was adjusted to 1.5. 1% magnetic composite material was added, and an ozone generator (ozone concentration 50 mg / L, gas flow rate 0.5 L / min) and gas pump were turned on. The reaction temperature was 30℃ and the reaction time was 8 hours.

[0091] After the reaction, the magnetic material is recovered using a magnetic recovery device with a recovery rate of 96%. A radioactive detector detects the uranium concentration at the slurry inlet. When the concentration is below 0.1 μSf / h, the slurry is circulated back to the reactor via an electronic three-way valve.

[0092] The test results showed that the uranium leaching rate reached 85%, and the ozone utilization rate was 33% higher than that of the acid leaching method.

[0093] Example 5

[0094] This embodiment provides a method for ozone-catalytic leaching of mudstone-type uranium ore, the steps of which are as follows:

[0095] (1) Preparation of magnetic composite materials

[0096] Dry and crushed sugarcane bagasse was mixed with natural hematite powder at a mass ratio of 20:1. The mixture was heated to 800°C at a rate of 5°C / min under a nitrogen atmosphere and held at that temperature for 1 hour. After cooling, a magnetic composite material was obtained by magnetic separation. The surface morphology is as follows: Figure 2 As shown in the figure. Characterization shows that the material contains 58% magnetite and has a specific surface area of ​​53 m². 2 / g.

[0097] (2) Leaching

[0098] The test ore was taken from a mudstone-type uranium deposit in Qingyuan, Guangdong (uranium grade 0.045%). The ore was crushed to -200 mesh, and a slurry with a solid-liquid ratio of 1:10 was prepared and the pH was adjusted to 2.0. 5% magnetic composite material was added, and an ozone generator (ozone concentration 200 mg / L, gas flow rate 2.0 L / min) and gas pump were turned on. The reaction temperature was 60℃ and the reaction time was 2 hours.

[0099] After the reaction, the magnetic material is recovered using a magnetic recovery device with a recovery rate of 96%. A radioactive detector detects the uranium concentration at the slurry inlet. When the concentration is below 0.1 μSf / h, the slurry is circulated back to the reactor via an electronic three-way valve.

[0100] The test results showed that the uranium leaching rate reached 88%, and the ozone utilization rate was 36% higher than that of the acid leaching method.

[0101] Example 6

[0102] The only difference from Example 1 is that the bagasse in step (1) was replaced with an equal amount of straw. The results showed that the uranium leaching rate reached 90%, but the catalyst recovery rate slightly decreased to 94%.

[0103] Example 7

[0104] The only difference from Example 1 is that the bagasse in step (1) was replaced with an equal amount of rice husks. The results showed that the uranium leaching rate reached 89%, the catalyst stability was slightly poor, and the leaching rate dropped to 85% in the fifth batch.

[0105] Example 8

[0106] The only difference from Example 1 is that in step (1), bagasse and natural hematite powder are mixed at a mass ratio of 0.5:1. The test results show that the uranium leaching rate reaches 70%, and the catalyst activity decreases due to uneven dispersion caused by excessive iron content.

[0107] Example 9

[0108] The only difference from Example 1 is that in step (1), bagasse and natural hematite powder are mixed at a mass ratio of 10:1. The test results show that the uranium leaching rate reaches 89%, and the catalyst activity is comparable to that of Example 1.

[0109] Example 10

[0110] The only difference from Example 1 is that in step (1), bagasse and natural hematite powder are mixed at a mass ratio of 20:1. The test results show that the uranium leaching rate reaches 78%, and the excess biomass slightly affects the density of active sites.

[0111] Example 11

[0112] The only difference from Example 1 is that in step (1), bagasse and natural hematite powder are mixed at a mass ratio of 25:1. The test results show that the uranium leaching rate reaches 67%, and excessive carrier weakens the catalytic efficiency of iron species.

[0113] Example 12

[0114] The only difference from Example 1 is that 0.5% magnetic composite material was added in step (2). The results showed that the uranium leaching rate reached 69%, and the insufficient amount of catalyst led to incomplete reaction.

[0115] Example 13

[0116] The only difference from Example 1 is that 8% magnetic composite material was added in step (2). The results showed that the uranium leaching rate reached 90%, and the excess catalyst did not further improve the efficiency.

[0117] Example 14 (No Slurry Circulation)

[0118] The same conditions as in Example 1 were used, but the electronic three-way valve was closed and slurry circulation was not performed. The results showed that the uranium leaching rate was 82%, a decrease of 10% compared to Example 1.

[0119] Example 15

[0120] The only difference from Example 1 is that the reaction temperature was changed to 10°C. The results showed that the uranium leaching rate reached 70%, and the low temperature led to slow reaction kinetics.

[0121] Comparative Example 1: Recycling of Non-Magnetic Materials

[0122] The same conditions as in Example 1 were used, but without the magnetic recovery device 9. The magnetic material flowed out with the slurry and could not be recovered. After five cycles, the total catalyst loss rate reached 80%, and the uranium leaching rate decreased to 55%.

[0123] Comparative Example 2: No catalyst added

[0124] The same conditions as in Example 1 were used, but without the addition of any catalyst. The results showed that the uranium leaching rate was only 48%, the ozone consumption was 1.8 kg / t of ore, and ozone was significantly emitted during the reaction, with a utilization rate of less than 30%.

[0125] Comparative Example 3: Adding natural hematite powder

[0126] The same conditions as in Example 1 were used, but the magnetic composite material was replaced with an equal amount of natural hematite powder (specific surface area < 4.3 m²). 2 The results showed that the uranium leaching rate was 58%, the catalyst recovery rate was only 70%, and the leaching rate had dropped to 39% in the third batch.

[0127] Comparative Example 4: Traditional Acid Pickling Method

[0128] The steps are as follows: Leach with 5% sulfuric acid solution, solid-liquid ratio 1:5, reaction temperature 40℃, time 4 hours, without adding catalyst or ozone.

[0129] The results showed that the uranium leaching rate was 52%, the acid consumption was as high as 3.2 kg / t of ore, and the wastewater treatment cost increased significantly.

[0130] The above experimental results fully demonstrate that the present invention significantly improves uranium leaching efficiency and resource utilization by optimizing reactor structure and process flow, with effects that are significantly better than traditional acid leaching methods. The magnetic composite material prepared by the present invention is superior to traditional materials in terms of catalytic activity, structural stability, and magnetic recovery performance, and can effectively improve uranium leaching efficiency and reduce operating costs.

[0131] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for ozone-catalytic leaching of mudstone-type uranium ore, characterized in that, include: Biomass raw materials and iron-based material powders are mixed and treated at high temperature of 500℃-800℃ for 1 h-3 h. After cooling, they are separated by magnetic separation to obtain magnetic composite materials. The mudstone-type uranium ore is crushed and slurried. The resulting slurry is mixed and reacted with the magnetic composite material. The reaction temperature is controlled at 30℃-60℃. During the reaction, ozone is introduced into the reactor through an aeration disc. A spiral guide plate is installed in the reactor. After the reaction, the magnetic material is recovered through a magnetic recovery device. In the process of preparing the magnetic composite material, the mass ratio of the biomass raw material to the iron-based material powder is controlled to be (1-20):1; the iron-based material powder is selected from at least one of hematite powder and magnetite powder; the biomass raw material is selected from at least one of sugarcane bagasse, rice husk, sawdust and straw; During the crushing and pulping process of mudstone-type uranium ore, the solid-liquid ratio of the slurry is controlled at 1:(5-10); the mass ratio of the magnetic composite material to the slurry is (1-5):100; after adjusting the pH value of the slurry to 1.5-2.0, it is then mixed with the magnetic composite material.

2. The method for ozone-catalytic leaching of mudstone-type uranium deposits according to claim 1, characterized in that, The high-temperature treatment is carried out under an inert atmosphere; And / or, the biomass raw materials are dried and crushed before mixing.

3. The method for ozone-catalytic leaching of mudstone-type uranium ore according to claim 1, characterized in that, The ozone concentration in the reactor is controlled at 50 mg / L-200 mg / L, and the ozone flow rate is 0.5 L / min-2.0 L / min; And / or, the aeration disc is a microporous aeration disc with a pore size of 80 μm-120 μm; And / or, ozone is generated using an ozone generator, delivered to the bottom of the reactor via an air pump and aerated through the aeration disc, and the ozone is returned to the ozone generator from the top of the reactor via a gas return pipeline.

4. The method for ozone-catalytic leaching of mudstone-type uranium ore according to claim 1, characterized in that, After a reaction of 2-8 hours, the magnetic material is recovered using the magnetic recovery device. And / or, the magnetic recovery device uses a permanent magnet or an electromagnet, and controls the magnetic field strength to be 0.5 T-2.0 T.

5. The method for ozone-catalytic leaching of mudstone-type uranium ore according to claim 1, characterized in that, The reactor is equipped with an external reflux pipeline, on which a radioactive detector is installed. The radioactive detector is used to detect the uranium concentration. When the concentration is lower than a set value, the slurry is returned to the reactor through the control system to continue the reaction.

6. The method for ozone-catalytic leaching of mudstone-type uranium ore according to claim 1, characterized in that, The reactor has a cylindrical structure, and the spiral guide plate extends from the top to the bottom of the reactor. The pitch of the spiral guide plate is 100 mm-300 mm, and the angle between the guide plate and the horizontal plane is 15°-30°.

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