Method for circularly leaching uranium by electrochemically catalyzing cerium

Abstract

The invention provides a method for circularly leaching uranium from cerium oxide through electrochemical catalysis, which belongs to the technical field of uranium mining and metallurgy and comprises the following steps: preparing a leaching solution containing ceric ammonium nitrate and sulfuric acid; adding the crushed uranium ore into the leaching solution, and leaching to obtain a leaching solution; adsorbing the leachate by using an ion exchange resin column; eluting the adsorbed ion exchange resin column to obtain uranium-containing eluent; precipitating, filtering and drying the uranium-containing eluent to obtain a uranium compound product; and adsorbing tail liquid obtained after leach liquor passes through an ion exchange resin column is electrolyzed to oxidize and regenerate Ce (III) into Ce (IV) for recycling. The method for cyclically leaching uranium through electrochemical catalysis of cerium oxide is efficient, environmentally friendly, sustainable, economical and feasible.

Description

Technical Field

[0001] The invention relates to the technical field of uranium mining and metallurgy, and in particular to a method for leaching uranium by electrochemical catalysis of cerium in a circular manner. Background Art

[0002] As a key strategic resource, uranium plays an irreplaceable role in nuclear power generation, the defense industry, and other fields. Global demand for clean energy continues to grow. As a low-carbon, efficient form of energy, the development of nuclear energy is crucial for alleviating energy crises and addressing climate change. The efficient development and utilization of uranium resources is the core foundation for the sustainable development of the nuclear energy industry.

[0003] Traditional uranium leaching methods are mainly divided into acid leaching and alkaline leaching. Acid leaching typically uses strong acids such as sulfuric acid as the leaching agent. This method has the advantage of high uranium leaching efficiency, but it also corrodes equipment, increases maintenance costs, and requires infrequent replacement. It also requires high equipment material requirements, resulting in a huge initial investment in equipment. Furthermore, the wastewater after leaching contains a large amount of acidic substances and heavy metal ions, and the wastewater treatment process requires a significant investment in manpower, materials, and financial resources. According to statistics, the cost of treating each ton of uranium-containing acidic wastewater ranges from tens to hundreds of yuan, making it a relatively high cost.

[0004] While alkaline leaching is relatively mild, its leaching rate is generally lower, and it is highly selective and limited in terms of ore type. For some complex uranium ores, alkaline leaching often fails to achieve ideal results. For example, in uranium ores containing large amounts of carbonates, the carbonates react with the alkali during alkaline leaching, consuming significant amounts of alkaline reagent and affecting uranium leaching efficiency. Similarly, with increasingly stringent environmental standards, traditional alkaline leaching methods for uranium ore are facing increasing environmental pressure.

[0005] In recent years, research on uranium leaching using chemical recycling systems has become a hot topic. However, existing chemical recycling systems generally suffer from low recycling efficiency and high costs. For example, the oxidants used in some chemical recycling systems are expensive and difficult to recycle, resulting in high leaching costs. Alternatively, some chemical recycling systems employ specialized organic oxidants, which are also expensive and difficult to recover and regenerate after the reaction, significantly increasing the cost per ton of uranium produced.

[0006] Therefore, developing an efficient, environmentally friendly, sustainable and economically feasible uranium leaching method has become a key issue that needs to be urgently addressed in the current uranium mining field. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a highly efficient, environmentally friendly, sustainable and economically feasible method for cyclic leaching of uranium by electrochemical catalytic cerium oxide.

[0008] To solve the above technical problems, the present invention provides a method for cyclic leaching of uranium using electrochemical catalytic cerium oxide, comprising the following steps:

[0009] preparing a leaching solution containing ammonium cerium nitrate and sulfuric acid;

[0010] adding the crushed uranium ore into a leaching solution to obtain a leaching solution;

[0011] The leachate is adsorbed on an ion exchange resin column;

[0012] The adsorbed ion exchange resin column is eluted to obtain an eluate containing uranium;

[0013] The uranium-containing eluate is precipitated, filtered, and dried to obtain a uranium compound product;

[0014] The adsorption tail liquid obtained after the leachate passes through the ion exchange resin column is electrolyzed to oxidize Ce(III) and regenerate Ce(IV) for recycling.

[0015] Furthermore, the concentration of ammonium cerium nitrate in the leachate is 0.1-0.5 mol / L, and the concentration of sulfuric acid is 0.5-2 mol / L.

[0016] Furthermore, an additive consisting of citric acid and ethylenediaminetetraacetic acid is added to the leachate, and the total concentration of the additive in the leachate is 0.01 to 0.05 mol / L.

[0017] Furthermore, the particle size of the crushed uranium ore is 0.1-0.5 mm, the liquid-solid ratio of the uranium ore to the leaching solution is 3:1-6:1, the leaching temperature is 40-60° C., the leaching time is 4-8 hours, and the leaching is carried out at a stirring speed of 200-400 r / min.

[0018] Furthermore, when the leachate is adsorbed by an ion exchange resin column, the leachate flow rate is controlled at 3-4 mL / min and the temperature is controlled at 30-40°C.

[0019] Furthermore, the ion exchange resin column is filled with strong basic anion exchange resins including D231 and 201×7.

[0020] Furthermore, the elution of the ion exchange resin column after adsorption adopts segmented elution, including:

[0021] First, elute with a mixture of 0.5-0.7 mol / L sodium carbonate and 0.1-0.2 mol / L sodium bicarbonate;

[0022] Then elute with a mixed solution of 0.8-1 mol / L sodium carbonate and 0.2-0.3 mol / L sodium bicarbonate.

[0023] Furthermore, the uranium-containing eluate precipitate can be prepared by adding a saturated sodium hydroxide solution to the uranium-containing eluate to react and generate a sodium diuranate precipitate.

[0024] Furthermore, the electrolysis of the adsorption tail liquid is to transfer the adsorption tail liquid to an electrolytic cell, with graphite as the anode and stainless steel as the cathode, the anode area and the cathode area are separated by a cation exchange membrane, and direct current is introduced into the electrolytic cell for electrolysis.

[0025] Furthermore, the current density of the electrolysis is 10 to 30 mA / cm 2 , the electrolysis voltage is 2~4V.

[0026] The present invention provides a method for cyclically leaching uranium using electrochemical catalytic cerium oxide. By optimizing the composition of the leaching solution, selecting ceric ammonium nitrate and sulfuric acid as the main components of the leaching solution, precisely controlling the leaching conditions, and introducing advanced electrochemical catalytic regeneration technology, the method significantly improves the uranium leaching rate, enabling more efficient recovery of uranium ore resources and improving resource utilization. Under identical experimental conditions, the uranium leaching method provided by the present invention achieves a leaching rate of 80% to 90%, compared to approximately 70% for conventional uranium leaching methods. Compared to conventional uranium leaching methods, the present invention achieves a leaching rate improvement of 10% to 20%.

[0027] Furthermore, the present invention provides a method for uranium leaching using electrochemical catalytic cerium oxide. Compared to traditional strong-acid leaching methods, the leaching solution used in this invention is relatively less acidic, and the presence of additives forms a protective film on the equipment surface, further reducing the corrosion caused by the solution. This not only extends the equipment's service life and reduces maintenance and replacement costs, but also reduces the risk of production interruptions due to equipment corrosion. It is estimated that the present method for uranium leaching can extend the equipment's service life by 2-3 years, saving approximately 30-50% in annual maintenance and replacement costs.

[0028] Furthermore, the present invention provides a method for cyclically leaching uranium from electrochemically catalyzed cerium oxide, which utilizes an ion exchange method to recover uranium in a relatively simple process. The resulting wastewater, waste residue, and other pollutants are relatively low and easy to handle. The entire leaching process complies with current stringent environmental protection requirements, contributing to the coordinated development of uranium mining and environmental protection. Ultimately, the heavy metal ion content in the wastewater produced by the present method of uranium leaching is less than 50% of the national emission standard, significantly reducing environmental pollution and lowering production costs.

[0029] In addition, the present invention provides a method for cyclic leaching of uranium using electrochemical catalytic cerium oxide. The adsorption tail liquid obtained after ion adsorption is electrolyzed, and electrochemical catalytic regeneration can greatly reduce chemical reagent consumption and reduce waste generation. Furthermore, Ce(III) in the adsorption tail liquid can be regenerated into Ce(IV) through electrolytic oxidation, which can be further recycled for leaching uranium ore. By recycling Ce(IV), the use of expensive oxidants is reduced, lowering raw material costs.

[0030] Therefore, the electrochemical catalytic cerium oxide cyclic leaching method provided by the present invention can reduce equipment corrosion and lower equipment maintenance and replacement costs. Furthermore, optimized process conditions and efficient resource recovery further improve production efficiency and correspondingly reduce energy consumption and costs per unit of output. Calculations show that the electrochemical catalytic cerium oxide cyclic leaching method provided by the present invention can reduce the cost per ton of uranium produced by 10% to 20% compared to traditional methods, making uranium leaching methods from uranium ore more economically competitive. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a method for cyclic leaching of uranium using electrochemical catalytic cerium oxide provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] See also Figure 1 The embodiment of the present invention provides a method for electrochemically catalyzing cerium oxide cyclic leaching of uranium, comprising the following steps:

[0033] Step 1) preparing a leaching solution containing ammonium cerium nitrate and sulfuric acid.

[0034] The concentration of ammonium cerium nitrate in the prepared leaching solution is 0.1-0.5 mol / L, and the concentration of sulfuric acid is 0.5-0.2 mol / L.

[0035] Among them, ammonium cerium nitrate has oxidizing properties. As a key reagent for oxidative leaching of uranium, controlling the concentration of ammonium cerium nitrate in the leaching solution at 0.1-0.5 mol / L can ensure that Ce(IV) in the ammonium cerium nitrate has sufficient oxidizing ability, so that in the subsequent leaching process, the tetravalent uranium in the uranium ore can be effectively oxidized to hexavalent uranium, while avoiding problems such as high cost and subsequent processing difficulties caused by its excessive concentration.

[0036] Sulfuric acid not only provides the necessary acidic environment for subsequent leaching reactions and promotes the dissolution of uranium ore, but also participates in redox reactions and maintains the stability of the leaching system. Therefore, its concentration is controlled at 0.5-2 mol / L.

[0037] At the same time, in order to further improve the performance of the leaching solution, citric acid (C6H8O7) and ethylenediaminetetraacetic acid (EDTA, C 10 H 16 N2O8) and the total concentration of the additive in the leaching solution is 0.01-0.05 mol / L. The additives composed of these two components can react with metal ions (such as Fe 3+ , Ca 2+ Mg 2+ The additives can also alter the chemical environment of the solution, helping to improve uranium leaching efficiency.

[0038] The present invention provides a method for cyclically leaching uranium using electrochemical catalytic cerium oxide. This method uses a relatively weakly acidic leaching solution composed primarily of ceric ammonium nitrate and sulfuric acid. Additives that react to form a protective film on the surface of the equipment further reduce corrosion caused by the solution, thereby extending the equipment's service life, reducing maintenance and replacement costs, and minimizing the risk of production interruptions due to equipment corrosion. The leaching solution provided by this method can extend the equipment's service life by 2-3 years, saving approximately 30-50% in annual maintenance and replacement costs.

[0039] Step 2) adding the crushed uranium ore into a leaching solution to obtain a leaching solution.

[0040] The particle size of the crushed uranium ore is controlled to be between 0.1 and 0.5 mm. By controlling the particle size of the uranium ore, the contact area between the uranium ore and the leaching solution can be increased, thereby significantly increasing the leaching reaction rate.

[0041] Furthermore, in order to fully and completely leach the uranium in the uranium ore, the liquid-to-solid ratio of the uranium ore to the leaching solution is controlled within a range of 3:1 to 6:1.

[0042] At the same time, in order to fully and efficiently leach the uranium in the uranium ore, the leaching temperature is controlled at 40-60°C. Leaching within this temperature range can not only ensure that the reaction has sufficient kinetic activity, but also avoid energy waste and increased equipment loss due to excessively high temperature.

[0043] In addition, in order to ensure that the uranium ore and the leaching solution are fully mixed and the leaching reaction proceeds evenly, the mixture of the uranium ore and the leaching solution is continuously stirred, and the stirring speed is controlled at 200 to 400 r / min.

[0044] Among them, the stirring device is driven by a variable frequency motor, and the stirring speed can be adjusted in real time within the range of 200 to 400 r / min according to the reaction progress. In the early stage of the reaction, it can be stirred quickly to ensure that the uranium ore and the leaching solution are fully mixed. In the later stage, the stirring speed can be appropriately reduced to maintain the stability of the leaching reaction.

[0045] The leaching reaction time is controlled to be 4 to 8 hours. Through reasonable time control, the uranium ore leaching reaction is ensured to be relatively complete. The crushed uranium ore is added to the prepared leaching solution.

[0046] During the leaching process, Ce(IV) in ammonium cerium nitrate exerts strong oxidizing properties and can oxidize low-valent uranium (such as U(IV)) in uranium ore into high-valent uranium (such as U(VI)). The chemical reaction equation is:

[0047] 2U(Ⅳ)+2Ce(Ⅳ)=2U(Ⅵ)+2Ce(Ⅲ).

[0048] The high-valent uranium (such as U(VI)) generated by the reaction is converted into UO2 in acidic solution. 2+ It exists in the form of ions, thereby achieving the dissolution and leaching of uranium from uranium ore to obtain UO2 2+ Ion leachate.

[0049] The present invention provides a method for cyclically leaching uranium using electrochemical catalytic cerium oxide. The method optimizes the composition of the leaching solution, selects a leaching solution containing ammonium cerium nitrate and sulfuric acid as main components, and precisely controls the leaching conditions. This method can significantly improve the uranium leaching rate, more fully recover uranium ore resources, and improve resource utilization. The leaching rate can reach 80% to 90%, which is 10% to 20% higher than that of traditional uranium ore leaching methods.

[0050] Step 3) The leachate is adsorbed using an ion exchange resin column.

[0051] Before the ion exchange resin method is used to recover the uranium in the leachate, the leachate is first filtered to remove suspended impurities in the leached liquid.

[0052] Among them, when the leachate is adsorbed by the ion exchange resin column, the dynamic ion exchange method is used to control the flow rate of the leachate at 3-4 mL / min and the temperature at 30-40 ° C to make the UO2 in the leachate 2+ The ions are in full contact with the resin, which improves the adsorption effect of UO22+ ions.

[0053] The ion exchange resin column is filled with strong alkaline anion exchange resins including D231 and 201×7.

[0054] Step 4) The adsorbed ion exchange resin column is eluted to obtain a uranium-containing eluate.

[0055] When the ion exchange resin column is saturated with adsorption, a mixed solution containing sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) is used to elute the ion exchange resin column.

[0056] The elution of the adsorption-saturated ion exchange resin column adopts segmented elution, including:

[0057] Initially, elution with a mixture of 0.5-0.7 mol / L sodium carbonate and 0.1-0.2 mol / L sodium bicarbonate can elute most of the uranium adsorbed on the ion exchange resin column. Further elution with a mixture of 0.8-1 mol / L sodium carbonate and 0.2-0.3 mol / L sodium bicarbonate can significantly increase the uranium recovery rate.

[0058] Step 5) The uranium-containing eluate is precipitated, filtered, and dried to obtain a uranium compound product.

[0059] To precipitate uranium from the uranium-containing eluate, a saturated sodium hydroxide solution can be added to the eluate to react the uranium in the solution to form sodium diuranate precipitate. The precipitated solution is then filtered, and the filtered solid is dried to obtain uranium compounds such as sodium diuranate.

[0060] The present invention provides a method for cyclically leaching uranium using electrochemical catalytic cerium oxide. The ion exchange method for uranium recovery is relatively simple, produces relatively little wastewater, waste residue, and other pollutants, and is easy to handle. The entire leaching process complies with current stringent environmental protection requirements, contributing to the coordinated development of uranium mining and environmental protection. Ultimately, the heavy metal ion content in the wastewater produced by the present invention's uranium leaching method is less than 50% of the national emission standard, significantly reducing environmental pollution and lowering production costs.

[0061] Step 6) The adsorption tail liquid obtained after the leaching liquid passes through the ion exchange resin column is electrolyzed to oxidize Ce(III) and regenerate Ce(IV) for recycling.

[0062] Among them, the adsorption tail liquid obtained after the leaching liquid passes through the ion exchange resin column contains trivalent Ce ions (i.e., Ce(III) ions) produced by oxidizing uranium ore with cerium ammonium nitrate. In order to oxidize the trivalent Ce ions in the adsorption tail liquid into tetravalent Ce ions (i.e., Ce(IV) ions) so that they can be recycled, the obtained adsorption tail liquid is electrolyzed.

[0063] First, the adsorbed tail liquid obtained after the ion exchange resin column is transferred to an electrolytic cell, which uses graphite as the anode and stainless steel as the cathode. The anode and cathode regions are separated by a cation exchange membrane to effectively prevent the reaction of the two polar products.

[0064] Then, a supporting electrolyte, sodium sulfate (Na2SO4), is added to the electrolytic cell with a concentration of 0.1 to 0.3 mol / L to improve the conductivity of the solution and reduce the energy consumption of electrolysis.

[0065] Then, direct current is introduced into the electrolytic cell, and the current density is precisely controlled to be 10-30 mA / cm 2 , the electrolysis voltage is 2~4V.

[0066] During the electrolysis process, Ce(Ⅲ) is oxidized to Ce(Ⅳ) at the anode, and the reaction equation is: Ce(Ⅲ)-e - =Ce(IV), thus achieving efficient regeneration of Ce(IV). The regenerated Ce(IV) can be recycled for uranium leaching, greatly reducing the consumption cost of chemical reagents and improving economic benefits.

[0067] At the cathode, hydrogen ions in the solution are reduced to generate hydrogen gas, and the reaction equation is: 2H++2e-=H2↑. The generated hydrogen gas can be collected and reasonably utilized to achieve comprehensive utilization of resources.

[0068] At the same time, the gas generated at the anode is collected and analyzed. By detecting the gas composition and content, the extent of the electrolysis reaction and whether there are side reactions can be judged so that the parameters during electrolysis can be adjusted in time.

[0069] The present invention provides a method for cyclically leaching uranium using electrochemical catalytic cerium oxide. The adsorption tail liquid obtained after ion adsorption is electrolyzed, and electrochemical catalytic regeneration can significantly reduce chemical reagent consumption and waste generation. Furthermore, Ce(III) in the adsorption tail liquid can be regenerated into Ce(IV) through electrolytic oxidation, which can be further recycled for uranium ore leaching. By recycling Ce(IV), the use of expensive oxidants can be reduced, lowering raw material costs and improving economic benefits.

[0070] The following examples specifically illustrate the method for cyclic leaching of uranium with electrochemical catalytic cerium oxide provided by the present invention.

[0071] Example 1

[0072] Preparation of the leachate: Accurately weigh 13.2 g of ammonium cerium nitrate and add it to 500 mL of distilled water, stirring to dissolve. Then, add 27.8 g of concentrated sulfuric acid and adjust the volume to 1 L to obtain a leachate with a concentration of 0.1 mol / L ammonium cerium nitrate and 0.5 mol / L sulfuric acid.

[0073] 1.5 g of citric acid and 1.8 g of ethylenediaminetetraacetic acid were weighed, added to the above-mentioned leaching solution, and stirred evenly to obtain a leaching solution containing additives. The total concentration of the additives was 0.01 mol / L.

[0074] Uranium Ore Leaching: Crush the uranium ore to a particle size of 0.1-0.3 mm. Weigh 100 g of the crushed uranium ore and add it to 1 L of the prepared leaching solution. Leaching is carried out in a constant-temperature water bath at 40°C, stirring at 200 rpm for 4 hours to produce a uranium-containing leachate. Calculated uranium leaching efficiency is 80%.

[0075] Uranium Recovery: The leachate is passed through an exchange column filled with a strongly basic anion exchange resin at a controlled flow rate of 5 mL / min and a temperature of 40°C. When the resin is saturated with adsorption, it is eluted with a mixed solution containing 0.5 mol / L sodium carbonate and 0.1 mol / L sodium bicarbonate at a flow rate of 3 mL / min to obtain an eluate containing uranium.

[0076] Electrochemical catalytic regeneration: The adsorption tail liquid obtained after the leachate is adsorbed by the ion exchange resin column is transferred to the electrolytic cell. The anode of the electrolytic cell uses a graphite electrode, the cathode uses a stainless steel electrode, and the anode area and the cathode area are separated by a cation exchange membrane.

[0077] Direct current is introduced into the electrolytic cell, and the current density is controlled to be 10 mA / cm 2 , the electrolysis voltage is 2 V. During the electrolysis process, the concentration of Ce(IV) in the anode solution is monitored in real time. When the Ce(IV) concentration reaches the set initial concentration, the electrolysis is stopped. The resulting Ce(IV)-containing solution can be returned as leachate to continue leaching the uranium ore, achieving the regeneration and recycling of the leachate, improving the use efficiency of the leachate, reducing costs, and improving economic benefits.

[0078] The uranium-containing eluate is collected, and an appropriate amount of sodium hydroxide solution is added to it to adjust the pH to 8-9, so that the uranium precipitates. After filtering, washing, and drying, the uranium compound product is obtained.

[0079] Example 2

[0080] Leachate preparation: Weigh 33g of ammonium cerium nitrate and add it to 500mL of distilled water, stirring to dissolve. Then add 55.6g of concentrated sulfuric acid and adjust the volume to 1L to obtain a leachate with a concentration of 0.25mol / L ammonium cerium nitrate and 1mol / L sulfuric acid.

[0081] 2.5 g of citric acid and 3 g of ethylenediaminetetraacetic acid were weighed, added to the above-mentioned leaching solution, and stirred evenly to obtain a leaching solution containing additives. The total concentration of the additives was 0.03 mol / L.

[0082] Uranium ore leaching: Crush the uranium ore to a particle size of 0.2-0.4 mm. Weigh 100 g of the crushed uranium ore and add it to 1 L of leaching solution. Leaching is carried out in a constant-temperature water bath at 50°C, stirring at 300 rpm for 6 hours to produce a uranium-containing leachate. Testing and calculation show a uranium leaching yield of 88%.

[0083] Uranium recovery: The leachate is passed through an ion exchange resin column and the elution steps are the same as in Example 1. The pH of the uranium-containing eluate is adjusted to 8-9 with sodium hydroxide, and the uranium compound product is obtained after precipitation, filtration, and drying.

[0084] Electrochemical catalytic regeneration: The adsorption tail liquid obtained after the leachate is adsorbed by the ion exchange resin column is transferred to the electrolytic cell. The electrode and diaphragm are arranged as in Example 1. Direct current is passed through and the current density is controlled to be 20 mA / cm 2 The electrolysis voltage is 3 V. After the electrolysis is completed, the solution containing Ce(IV) can be returned as a leaching solution to continue leaching the uranium ore, thus realizing the recycling of the leaching solution, improving the utilization efficiency of the leaching solution, reducing costs, and improving economic benefits.

[0085] Example 3

[0086] Leachate preparation: Weigh 66g of ammonium cerium nitrate and add it to 500mL of distilled water, stirring to dissolve. Then add 111.2g of concentrated sulfuric acid and adjust the volume to 1L to obtain a leachate with a concentration of 0.5mol / L ammonium cerium nitrate and 2mol / L sulfuric acid.

[0087] 3.5 g of citric acid and 4.2 g of ethylenediaminetetraacetic acid were weighed, added to the above-mentioned leaching solution, and stirred evenly to obtain a leaching solution containing additives. The total concentration of the additives was 0.05 mol / L.

[0088] Uranium ore leaching: Crush the uranium ore to a particle size of 0.3-0.5 mm. Weigh 100 g of the crushed uranium ore and add it to 1 L of leaching solution. Leaching is carried out in a constant-temperature water bath at 60°C, stirring at 400 rpm for 8 hours to produce a uranium-containing leachate. Testing and calculation show a uranium leaching yield of 92%.

[0089] Recovery of uranium: Ion exchange and elution were carried out in the same manner as in Examples 1 and 2, and the pH value was adjusted to precipitate uranium to obtain a uranium compound product.

[0090] Electrochemical catalytic regeneration: The adsorption tail liquid obtained after the leachate is adsorbed by the ion exchange resin column is transferred to the electrolytic cell, and a direct current is passed through, and the current density is controlled at 30mA / cm 2The electrolysis voltage is 4 V. After the electrolysis is completed, the solution containing Ce(IV) can be returned as a leaching solution to continue leaching the uranium ore, realizing the recycling of the leaching solution, improving the efficiency of the leaching solution, reducing costs, and improving economic benefits.

[0091] It can be seen from the above examples that the method for electrochemically catalyzing cerium cyclic leaching of uranium provided by the present invention can achieve good leaching effects under different conditions, and by optimizing the parameters of each step, the uranium leaching rate can be further improved, and has good application prospects.

[0092] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for cyclic leaching of uranium using electrochemical catalytic cerium oxide, characterized in that: The steps include: preparing a leaching solution containing ammonium cerium nitrate and sulfuric acid; adding the crushed uranium ore into a leaching solution to obtain a leaching solution; The leachate is adsorbed on an ion exchange resin column; The adsorbed ion exchange resin column is eluted to obtain an eluate containing uranium; The uranium-containing eluate is precipitated, filtered, and dried to obtain a uranium compound product; The adsorption tail liquid obtained after the leachate passes through the ion exchange resin column is electrolyzed to oxidize Ce(III) and regenerate Ce(IV) for recycling.

2. The method for cyclic leaching of uranium by electrochemical catalytic cerium oxide according to claim 1, characterized in that: The concentration of ammonium cerium nitrate in the leaching solution is 0.1-0.5 mol / L, and the concentration of sulfuric acid is 0.5-2 mol / L.

3. The method for cyclic leaching of uranium by electrochemical catalytic cerium oxide according to claim 2, characterized in that: An additive consisting of citric acid and ethylenediaminetetraacetic acid is added to the leaching solution, and the total concentration of the additive in the leaching solution is 0.01-0.05 mol / L.

4. The method for cyclic leaching of uranium by electrochemical catalytic cerium oxide according to claim 1, characterized in that: The particle size of the crushed uranium ore is 0.1-0.5 mm, the liquid-solid ratio of the uranium ore to the leaching solution is 3:1-6:1, the leaching temperature is 40-60° C., the leaching time is 4-8 hours, and the leaching is stirred at a speed of 200-400 r / min.

5. The method for cyclic leaching of uranium by electrochemical catalytic cerium oxide according to claim 4, characterized in that: When the leachate is adsorbed by the ion exchange resin column, the flow rate of the leachate is controlled at 3-4 mL / min and the temperature is controlled at 30-40°C.

6. The method for cyclic leaching of uranium by electrochemical catalytic cerium oxide according to claim 5, characterized in that: The ion exchange resin column is filled with strong alkaline anion exchange resins including D231 and 201×7.

7. The method for cyclic leaching of uranium by electrochemical catalytic cerium oxide according to claim 1, characterized in that: The elution of the adsorbed ion exchange resin column adopts segmented elution, including: First, elute with a mixture of 0.5-0.7 mol / L sodium carbonate and 0.1-0.2 mol / L sodium bicarbonate; Then elute with a mixed solution of 0.8-1 mol / L sodium carbonate and 0.2-0.3 mol / L sodium bicarbonate.

8. The method for cyclic leaching of uranium using electrochemical catalytic cerium oxide according to claim 1, characterized in that: The uranium-containing eluent precipitation can be prepared by adding a saturated sodium hydroxide solution into the uranium-containing eluent to react and generate a sodium diuranate precipitate.

9. The method for cyclic leaching of uranium using electrochemical catalytic cerium oxide according to claim 1, characterized in that: The electrolysis of the adsorption tail liquid is to transfer the adsorption tail liquid to an electrolytic cell, with graphite as the anode and stainless steel as the cathode, the anode area and the cathode area are separated by a cation exchange membrane, and direct current is introduced into the electrolytic cell for electrolysis.

10. The method for cyclic leaching of uranium using electrochemical catalytic cerium oxide according to claim 9, characterized in that: The current density of the electrolysis is 10-30 mA / cm 2 , the electrolysis voltage is 2~4V.

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