Strong oxidation activation method for argillaceous sandstone uranium ore by adopting persulfate oxidation method

Abstract

The invention provides a strong oxidation activation method for argillaceous sandstone uranium ore by adopting a persulfate oxidation method, and relates to the field of inorganic nano material application and uranium purification and conversion. The method comprises the steps that a persulfate solution and ore pulp of the argillaceous sandstone uranium ore are mixed, then iron-containing nanometer minerals are added, U (IV) in the argillaceous sandstone uranium ore is rapidly converted into U (VI) with higher mobility through an activation reaction between the iron-containing nanometer minerals and persulfate, then suspension liquid is filtered and washed, and high-concentration uranium leaching liquid is obtained; according to the argillaceous sandstone uranium ore activation method provided by the invention, not only can strong oxidizing free radicals be generated, but also a large number of uranyl sulfate ions can be formed to increase electrostatic repulsion of U (VI and clay, so that the leaching efficiency of uranium is improved; the concentration of U (VI) in the leachate obtained through the method is higher, the uranium content in the leaching residues is lower, the needed activation time is shorter, the activation mode has wide universality, and activation of various uranium ores can be met; the large-scale application is easy.

Description

Technical Field

[0001] The invention belongs to the field of inorganic nano material application and uranium purification and conversion, and relates to a strong oxidation activation method for muddy sandstone uranium ore using a persulfate oxidation method. Background Art

[0002] As a common type of uranium ore, argillaceous sandstone uranium ore usually coexists with clay minerals to form a complex mineral structure. Due to the presence of clay minerals, the uranium leaching efficiency is usually significantly affected. Clay minerals have strong adsorption capacity and are easy to adsorb and retain uranium ions during the leaching process, resulting in low uranium leaching rate, which in turn affects the recovery efficiency of uranium resources. Traditional uranium leaching methods, such as acid leaching or alkaline leaching, often have poor effects when treating argillaceous sandstone uranium ore. The leaching process is long and requires higher acidity and alkalinity. At the same time, the adsorption of uranium by clay minerals is difficult to effectively overcome, resulting in uranium loss and waste of resources.

[0003] At present, although some technologies have been tried to improve the leaching effect through chemical modification or physical methods, these methods have certain limitations, such as the need to rely on high temperature and strong acid environment, which not only increases energy consumption, but also may cause environmental pollution and equipment corrosion. In addition, most existing technologies have failed to effectively solve the problem of electrostatic interaction between clay minerals and uranyl anions, so it is difficult to further improve the leaching efficiency.

[0004] Therefore, how to improve the leaching efficiency of muddy sandstone uranium ore, especially how to ensure efficient leaching while avoiding the adsorption of uranium by clay minerals, is a technical problem that needs to be solved urgently in the current uranium leaching field. Summary of the invention

[0005] In view of this, in order to solve the above technical problems, the purpose of the present invention is to provide a strong oxidation activation method for muddy sandstone uranium ore using a persulfate oxidation method, which relates to the technical field of uranium ore resource development; the method comprises: after mixing a persulfate solution with the slurry of the muddy sandstone uranium ore, adding an iron-containing nano-mineral, generating a large number of strong oxidizing free radicals through the activation reaction between the iron-containing nano-mineral and the persulfate, quickly converting U(IV) in the muddy sandstone uranium ore into U(VI) with higher mobility, and then filtering and washing the suspension to obtain a high-concentration uranium leaching solution; the present invention provides a method for strongly oxidizing and activating argillaceous sandstone uranium ore using a persulfate oxidation method, which relates to the technical field of uranium ore resource development; the method comprises: mixing a persulfate solution with the slurry of the muddy sandstone uranium ore, adding an iron-containing nano-mineral, generating a large number of strong oxidizing free radicals through the activation reaction between the iron-containing nano-mineral and the persulfate, and rapidly converting U(IV) in the muddy sandstone uranium ore into U(VI) with higher mobility; and then filtering and washing the suspension to obtain a high-concentration uranium leaching solution; The activation method for muddy sandstone uranium ore provided by the invention can not only generate strong oxidizing free radicals, but also form a large number of uranyl sulfate ions to increase the electrostatic repulsion between U(VI) and clay, effectively reduce the adsorption of uranium by clay minerals, avoid uranium loss, and improve the leaching efficiency of uranium; the U(VI) concentration in the leaching solution obtained by the method is higher, and the uranium content in the leaching residue is lower. Compared with the traditional leaching method, the present invention improves the hindering effect of clay on uranium leaching under mild reaction conditions, improves the leaching efficiency of uranium, and has the advantages of simple operation, low energy consumption, and environmental friendliness.

[0006] At present, traditional uranium ore leaching methods often require the use of strong acids or oxidants, which not only pose a serious threat to the ecological environment, but also the presence of clay in argillaceous sandstone uranium ore hinders the leaching of uranium. In view of this, the present invention proposes a new method for activating uranium elements in argillaceous sandstone uranium ore, including: mixing a persulfate solution, an iron-containing nanomineral, and an argillaceous sandstone uranium ore pulp, and using the reaction between iron ions, persulfate molecules, oxygen, and water molecules to generate a variety of reactive free radicals (Equations 1-4) to oxidize U(IV) to U(VI), and using the electrostatic repulsion between uranyl sulfate anions and clay to improve the leaching efficiency of uranium. The whole reaction process avoids the use of strong acids and realizes faster leaching of uranium elements without increasing the leaching process flow.

[0007] S2O8 2− +2Fe 3+ →2Fe 2+ +2SO4 2− (1) S2O8 2− +Fe 2+ →Fe 3+ +SO4 •− +SO4 2− (2) SO4 •− +H2O→ • OH+HSO4 − (3) O2+Fe 2+ →Fe 3+ +O2 •− (4) To achieve the above object, the following technical solutions are adopted: A method for strongly oxidizing and activating argillaceous sandstone uranium ore by persulfate oxidation, including: Directly stirring and mixing a persulfate solution, an iron-containing nanomineral, and a uranium ore pulp, and carrying out an activation reaction under stirring. After the reaction is completed, the leaching solution and the leaching residue are obtained by filtration.

[0008] Further, the original concentration of the persulfate solution is 1-40 mmol / L; the persulfate includes at least one of ammonium persulfate, potassium persulfate, sodium persulfate, and potassium monopersulfate.

[0009] Further, the original concentration of the persulfate solution is 10-30 mmol / L; the uranium ore includes argillaceous sandstone uranium ore.

[0010] Further, the activation method is: Mix the persulfate solution and the uranium ore pulp first, then add the iron-containing nano-minerals under stirring, and carry out the activation reaction under stirring. After the reaction is completed, filter to obtain the leachate and the leached residue.

[0011] Furthermore, the solid content of the uranium ore pulp is 1% - 50%; the stirring speed is 300 - 700 rpm.

[0012] Furthermore, the solid content of the uranium ore pulp is 5% - 10%; the concentration of the persulfate in the uranium ore pulp is 0.1 - 1.0 mmol / L; the iron-containing nano-minerals include at least one of pyrite, magnetite, hematite and ferrihydrite. Adding a small amount of iron compounds is used to provide Fe 2+ / Fe 3+ , and carry out the activation process under continuous stirring.

[0013] Furthermore, the concentration of the persulfate in the uranium ore pulp is 0.3 - 0.8 mmol / L; the dosage of the iron-containing nano-minerals is 0.05 - 0.5 g / L; the activation reaction time is 30 - 60 min.

[0014] Furthermore, the dosage of the iron-containing nano-minerals is 0.1 - 0.3 g / L.

[0015] Application of any of the above activation methods in uranium extraction from uranium ore.

[0016] Beneficial effects: The beneficial effects of the present invention are as follows: 1. Improve uranium leaching efficiency: Through the activation reaction of iron-containing nano-minerals and persulfate, strong oxidizing free radicals are generated, which can effectively convert U(IV) in the uranium ore into U(VI) with stronger mobility; on the other hand, the sulfate formed during the reaction can form uranyl sulfate anions with U(VI), enhancing the electrostatic repulsion with clay minerals in the argillaceous sandstone uranium ore, effectively reducing the adsorption of uranium by clay minerals, avoiding uranium loss, and improving the uranium recovery rate; 2. Reduce the uranium ore leaching time: Compared with the traditional acid leaching method or alkali leaching method, the method of the present invention can complete the oxidation conversion and leaching process of uranium in a shorter time, greatly shortening the reaction time and improving the production efficiency; 3. Low energy consumption and environmentally friendly: The persulfate oxidation technology adopted in the present invention can achieve efficient uranium leaching under mild reaction conditions, without the use of strong acids or high-temperature environments, reducing energy consumption and avoiding environmental pollution, equipment corrosion and other problems that may be brought about by traditional leaching methods, and having high environmental friendliness; 4. High-concentration uranium leaching solution and low-uranium leaching residue: The method of the present invention can generate a high-concentration uranium leaching solution, and at the same time, the uranium content in the leaching residue is significantly reduced, greatly improving the resource utilization rate and reducing the environmental burden of the waste residue. The present invention provides an efficient, environmentally friendly, and highly operable method for oxidizing and activating argillaceous sandstone uranium ore, providing a new technical path for the development and utilization of uranium ore resources and being suitable for large-scale popularization and application. Specific Embodiments

[0017] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. For those not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0018] Example 1: The test ore was taken from a certain argillaceous sandstone uranium deposit in Inner Mongolia (uranium grade is 0.035%), with fine particles and associated with a large amount of illite, kaolinite, calcite, and potassium feldspar.

[0019] 50 g of argillaceous sandstone uranium ore powder was added to 1000 mL of aqueous solution. Under a stirring speed of 300 rpm, it was continuously stirred for 10 min to obtain a homogeneous suspension. Then, 35 mL of an aqueous solution of ammonium persulfate with a concentration of 20 mmol / L was added to the above suspension and continuously stirred for 10 min. Finally, 0.1 g of pyrite was added to the above suspension and continuously stirred for 30 min. Then, the leaching system was filtered, the leaching residue was digested by the digestion method, and the content of uranium element in the digestion solution was detected by ICP-OES. The results showed that the content in the leaching residue was 0.005%.

[0020] Example 2: The test ore was taken from a certain argillaceous sandstone uranium deposit in Inner Mongolia (uranium grade is 0.035%), with fine particles and associated with a large amount of illite, kaolinite, calcite, and potassium feldspar.

[0021] Add 50 g of argillaceous sandstone uranium ore powder to 1000 mL of aqueous solution. Under a stirring speed of 300 rpm, continuously stir for 10 min to obtain a homogeneous suspension. Then, take 30 mL of an aqueous solution of potassium monopersulfate compound salt with a concentration of 30 mmol / L and add it to the above suspension, and continuously stir for 10 min. Finally, add 0.2 g of magnetite to the above suspension, continuously stir for 30 min, then filter the leaching system, digest the leaching residue by digestion method, and then use ICP-OES to detect the content of uranium element in the digestion solution. The result shows that the content in the leaching residue is 0.002%.

[0022] Example 3: The test ore is taken from a certain argillaceous sandstone uranium deposit in Inner Mongolia (uranium grade is 0.035%). The particles are fine, and a large amount of illite, kaolinite, calcite and potassium feldspar are associated.

[0023] Add 50 g of argillaceous sandstone uranium ore powder to 1000 mL of aqueous solution. Under a stirring speed of 300 rpm, continuously stir for 10 min to obtain a homogeneous suspension. Then, take 25 mL of an aqueous solution of potassium persulfate with a concentration of 25 mmol / L and add it to the above suspension, and continuously stir for 10 min. Finally, add 0.15 g of hematite to the above suspension, continuously stir for 30 min, then filter the leaching system, digest the leaching residue by digestion method, and then use ICP-OES to detect the content of uranium element in the digestion solution. The result shows that the content in the leaching residue is 0.004%.

[0024] Example 4: The test ore is taken from a certain argillaceous sandstone uranium deposit in Inner Mongolia (uranium grade is 0.035%). The particles are fine, and a large amount of illite, kaolinite, calcite and potassium feldspar are associated.

[0025] Add 50 g of argillaceous sandstone uranium ore powder to 1000 mL of aqueous solution. Under a stirring speed of 300 rpm, continuously stir for 10 min to obtain a homogeneous suspension. Then, take 50 mL of an aqueous solution of sodium persulfate with a concentration of 10 mmol / L and add it to the above suspension, and continuously stir for 10 min. Finally, add 0.35 g of ferrihydrite to the above suspension, continuously stir for 30 min, then filter the leaching system, digest the leaching residue by digestion method, and then use ICP-OES to detect the content of uranium element in the digestion solution. The result shows that the content in the leaching residue is 0.005%.

[0026] Comparative Example 1: The test ore is taken from a certain argillaceous sandstone uranium deposit in Inner Mongolia (uranium grade is 0.035%). The particles are fine, and a large amount of illite, kaolinite, calcite and potassium feldspar are associated.

[0027] Add 50 g of argillaceous sandstone uranium ore powder to 1000 mL of aqueous solution. Under a stirring speed of 300 rpm, continuously stir for 10 min to obtain a homogeneous suspension. Then add 50 mL of sulfuric acid solution to the suspension and continuously stir for 30 min. Finally, filter the leaching system, digest the leaching residue by digestion method, and then use ICP-OES to detect the content of uranium element in the digestion solution. The calculation result shows that the content in the leaching residue is 0.016%.

[0028] Comparative Example 2: The test ore is taken from a certain argillaceous sandstone uranium deposit in Inner Mongolia (uranium grade is 0.035%). The particles are fine, and a large amount of illite, kaolinite, calcite and potassium feldspar are associated.

[0029] Add 50 g of argillaceous sandstone uranium ore powder to 1000 mL of aqueous solution. Under a stirring speed of 300 rpm, continuously stir for 10 min to obtain a homogeneous suspension. Then add 20 mL of potassium permanganate solution to the suspension and continuously stir for 30 min. Finally, filter the leaching system, digest the leaching residue by digestion method, and then use ICP-OES to detect the content of uranium element in the digestion solution. The calculation result shows that the content in the leaching residue is 0.009%.

[0030] Comparative Example 3: The test ore is taken from a certain argillaceous sandstone uranium deposit in Inner Mongolia (uranium grade is 0.035%). The particles are fine, and a large amount of illite, kaolinite, calcite and potassium feldspar are associated.

[0031] Add 50 g of argillaceous sandstone uranium ore powder to 1000 mL of aqueous solution. Under a stirring speed of 300 rpm, continuously stir for 10 min to obtain a homogeneous suspension. Then take 35 mL of ammonium persulfate aqueous solution with a concentration of 20 mmol / L and add it to the above suspension, and continuously stir for 40 min. Then filter the leaching system, digest the leaching residue by digestion method, and then use ICP-OES to detect the content of uranium element in the digestion solution. The result shows that the content in the leaching residue is 0.029%.

[0032] Comparative Example 4: The test ore is taken from a certain argillaceous sandstone uranium deposit in Inner Mongolia (uranium grade is 0.035%). The particles are fine, and a large amount of illite, kaolinite, calcite and potassium feldspar are associated.

[0033] Add 50 g of argillaceous sandstone uranium ore powder to 1000 mL of aqueous solution. Under the stirring speed of 300 rpm, continuously stir for 10 min to obtain a homogeneous suspension. Add 0.1 g of pyrite to the above suspension, continuously stir for 40 min, then filter the leaching system, digest the leaching residue by digestion method, and then use ICP-OES to detect the content of uranium element in the digestion solution. The result shows that the content in the leaching residue is 0.032%.

[0034] The U content in the leaching residue of each case is shown in Table 1: Table 1 U content in the leaching residue of each case To sum up, the strong oxidation activation method of argillaceous sandstone uranium ore using the persulfate oxidation method provided by the present invention is based on the oxidation reaction between persulfate, iron-containing nano-minerals, water and oxygen to generate a variety of strongly oxidizing free radicals, thereby realizing the oxidation of U(Ⅳ) in argillaceous sandstone uranium ore, and using the electrostatic repulsion between uranyl sulfate and clay to improve the leaching efficiency of uranium element.

[0035] The present invention provides an activation method for argillaceous sandstone uranium ore based on persulfate oxidation technology. By mixing a persulfate solution with iron-containing nano-minerals and pulp, highly active sulfate radicals, hydroxyl radicals and superoxide radicals are generated to rapidly oxidize tetravalent uranium to hexavalent uranium, and the electrostatic repulsion between uranyl sulfate and clay is used to reduce the adsorption of uranium by clay. This method does not require a high-temperature and high-pressure environment, avoids the use of strong acids or highly toxic oxidants, reduces environmental pollution, and improves the safety and environmental protection of operation. Compared with traditional methods, this technology has stronger oxidation ability and shorter activation time. Its characteristics of being green, efficient and easy to scale make it have important application value in the development of uranium ore resources and provide better technical support for nuclear energy supply.

[0036] As mentioned above, it is not any form of limitation to the present invention. Although the present invention has been disclosed by the above embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the above-disclosed technical content as equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A strong oxidation activation method for argillaceous sandstone uranium ore using the persulfate oxidation method, characterized in that, The activation method includes: Directly stirring and mixing a persulfate solution, an iron-containing nanomineral, and a uranium ore pulp, and then carrying out an activation reaction under stirring. After the reaction ends, the leachate and the leached residue are obtained by filtration.

2. A method for strongly oxidizing and activating argillaceous sandstone uranium ore using the persulfate oxidation method as described in claim 1, characterized in that, The uranium ore pulp is a pulp of the original ore of argillaceous sandstone uranium ore that has been crushed and screened to have a particle size less than 0.74 μm and contains montmorillonite, kaolinite, and illite clays.

3. A strong oxidation activation method for argillaceous sandstone uranium ore using the persulfate oxidation method as described in claim 1, characterized in that The original concentration of the persulfate solution is 1 to 40 mmol / L; the persulfate includes at least one of ammonium persulfate, potassium persulfate, sodium persulfate, and potassium monopersulfate.

4. A method for strongly oxidizing and activating argillaceous sandstone uranium ore by persulfate oxidation method as described in claim 1, characterized in that, The original concentration of the persulfate solution is 10 to 30 mmol / L; the uranium ore includes argillaceous sandstone uranium ore.

5. A strong oxidation activation method for argillaceous sandstone uranium ore using persulfate oxidation method as described in claim 1, characterized in that, The activation method is as follows: First, mix the persulfate solution and the uranium ore pulp, then add the iron-containing nanomineral under stirring, and carry out the activation reaction under stirring. After the reaction ends, the leachate and the leached residue are obtained by filtration.

6. A strong oxidation activation method for argillaceous sandstone uranium ore using the persulfate oxidation method as described in claim 1, characterized in that, The solid content of the uranium ore pulp is 1% to 50%; the rotation speed of the stirring is 300 to 700 rpm.

7. A strong oxidation activation method for argillaceous sandstone uranium ore using persulfate oxidation method as described in claim 1, characterized in that, The solid content of the uranium ore pulp is 5% to 10%; the concentration of the persulfate in the uranium ore pulp is 0.1 to 1.0 mmol / L; the iron-containing nanomineral includes at least one of pyrite, magnetite, hematite, and ferrihydrite.

8. A method for strongly oxidizing and activating argillaceous sandstone uranium ore by persulfate oxidation method as described in claim 1, characterized in that, The concentration of the persulfate in the uranium ore pulp is 0.3 to 0.8 mmol / L; the dosage of the iron-containing nanomineral is 0.05 to 0.5 g / L; the activation reaction time is 30 to 60 min.

9. A strong oxidation activation method for argillaceous sandstone uranium ore using the persulfate oxidation method as described in claim 1, characterized in that, The dosage of the iron-containing nanomineral is 0.1 to 0.3 g / L.

10. Application of the activation method according to any one of claims 1-9 in uranium extraction from uranium ore by leaching.

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