Separation of hydrogenated kerosene from TBP in a natural uranium extraction agent

Abstract

A method for separating hydrogenated kerosene and TBP in a natural uranium extractant includes the following steps: First, at room temperature, take 20 mL of the uranium-containing mixed organic solvent to be treated and mix it thoroughly with 11–14.5 mol / L analytical grade phosphoric acid at a volume ratio of 1:1–1:2 for 5–10 min, with 1–5 separation stages, and allow the reaction to stand at 20–30°C. After standing, take the lower liquid phase, which is an H3PO4·nTBP solution, and the upper liquid phase is hydrogenated kerosene. At this point, the hydrogenated kerosene content in the upper liquid after separation can reach over 97%. Second, add 2–3 mol / L nitric acid aqueous solution to the obtained H3PO4·nTBP solution, with a two-phase flow ratio of 1:1–1:2 and 2–3 separation stages, allowing the reaction to stand at 20–30°C. Take the supernatant, which is the TBP product liquid, thus achieving separation. Third, prepare an extractant using the separated TBP and hydrogenated kerosene, and conduct a comparative experiment with fresh extractant.

Description

Technical Field

[0001] This invention relates to the field of uranium-containing organic solvent separation technology. Specifically, it relates to a method for separating hydrogenated kerosene and TBP in a natural uranium extractant. Background Technology

[0002] In the nuclear fuel cycle, the extraction and purification of uranyl nitrate solution is a crucial step. Using extraction equipment, the uranyl nitrate solution containing impurities undergoes an extraction-washing-back-extraction process. Utilizing the principle of TBP in the organic solvent complexing with uranyl nitrate during extraction, impurities such as nickel, chromium, sodium, and magnesium are removed from the feed solution, achieving the purification objective.

[0003] During the production process, when the back-extraction agent, feed liquid, and other aqueous solutions containing nitric acid and uranyl nitrate come into contact with the organic solvent TBP-hydrogenated kerosene, a certain amount of TBP will dissolve in the aqueous solution at a certain solubility or be carried into the aqueous solution. Related literature indicates that mixing TBP with a high-temperature nitric acid-containing uranyl nitrate solution can cause a "red oil" explosion. To avoid this explosion, the aqueous solution that has come into contact with TBP must undergo an oil removal process before being sent to the next process. This oil removal process involves mixing the aqueous solution with fresh hydrogenated kerosene, allowing the TBP in the aqueous solution to dissolve into the hydrogenated kerosene based on the principle of "like dissolves like."

[0004] In actual production, the fresh hydrogenated kerosene used in the degreasing process is recycled. To ensure a certain degreasing efficiency, the TBP content in the fresh hydrogenated kerosene must be controlled. Once the TBP content in the hydrogenated kerosene reaches a certain value, the hydrogenated kerosene used for degreasing needs to be replaced, resulting in a mixed organic solvent of TBP and hydrogenated kerosene. Currently, there is no proper treatment or disposal method for this mixed organic solvent, and it can only be temporarily stored in storage tanks. The volume of these mixed organic materials stored increases year by year, and their long-term storage increases the company's safety risks and management costs.

[0005] To address the storage problem of TBP-hydrogenated kerosene mixed organic solvents, a study was conducted on the separation of TBP and hydrogenated kerosene in uranium-containing TBP-hydrogenated kerosene mixed organic compounds, aiming to recover relatively pure TBP and hydrogenated kerosene solvents. Summary of the Invention

[0006] The purpose of this invention is to separate TBP and hydrogenated kerosene from uranium-containing TBP-hydrogenated kerosene mixed organic matter, and to recover TBP and hydrogenated kerosene as single components. This not only reduces the storage pressure of mixed organic solvents and lowers the safety management risks and costs of organic matter, but also obtains TBP and hydrogenated kerosene as single components, maximizing the reuse of TBP and hydrogenated kerosene and reducing the reagent costs in production.

[0007] The technical solution of the present invention is as follows:

[0008] The first step involves taking 20 mL of the uranium-containing mixed organic solvent to be treated at room temperature and mixing it thoroughly with 11–14.5 mol / L analytical grade phosphoric acid at a volume ratio of 1:1 to 1:2 for 5–10 min, separating it into 1–5 stages (i.e., mixing and reacting 1–5 times). The mixture is then allowed to stand at 20–30 °C. After standing, the lower liquid phase is collected, yielding an H3PO4·nTBP solution, while the upper liquid phase is hydrogenated kerosene. At this point, the hydrogenated kerosene content in the upper liquid after separation can reach over 97%.

[0009] The second step involves adding 2–3 mol / L of nitric acid aqueous solution to the obtained H3PO4·nTBP solution, with a two-phase flow ratio of 1:1 to 1:2 and a separation stage of 2–3 stages. The reaction is allowed to stand at 20–30°C, and the supernatant is taken as the TBP product solution, thus achieving separation.

[0010] The third step involves preparing an extractant using the separated TBP and hydrogenated kerosene, and conducting a comparative experiment with the fresh extractant. The results show that the extraction effect of the TBP is close to that of the fresh extractant, thus meeting the process requirements.

[0011] The significant advantages of this invention are: by separating TBP from hydrogenated kerosene using the organic solvent TBP, the organic phase can be reused. This not only reduces the pressure in tank storage and lowers the safety risks and management costs of the organic phase storage process, but also ensures the stable operation of the oil removal process in the purification process, reducing operational risks. Furthermore, the reuse of the organic phase reduces production costs, increases the company's profits, and promotes cost reduction and efficiency improvement in the purification production line. Attached Figure Description

[0012] Figure 1 This is a simplified process flow diagram of the TBP separation technology in organic solvent TBP-hydrogenated kerosene described in this invention; Detailed Implementation

[0013] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0014] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” used in one or more embodiments of this application refers to and includes any or all possible combinations of one or more associated listed items.

[0015] Example 1:

[0016] The first step involves taking 20 mL of the uranium-containing mixed organic solvent to be treated at room temperature and mixing it thoroughly with 11 mol / L analytical grade phosphoric acid at a 1:1 volume ratio for 5 min. The separation stage is 1, and the reaction is allowed to stand at 20°C. After standing, the lower liquid phase is collected, yielding an H3PO4·nTBP solution, while the upper liquid phase is hydrogenated kerosene. At this point, the hydrogenated kerosene content in the upper liquid after separation can reach over 97%.

[0017] The second step involves adding 2 mol / L nitric acid aqueous solution to the obtained H3PO4·nTBP solution, with a two-phase flow ratio of 1:1 and a separation stage of 2. The reaction is allowed to stand at 20℃, and the supernatant is taken as the TBP product solution, thus achieving separation.

[0018] The third step involves preparing an extractant using the separated TBP and hydrogenated kerosene, and conducting a comparative experiment with the fresh extractant. The results show that the extraction effect of the TBP is close to that of the fresh extractant, thus meeting the process requirements.

[0019] Example 2:

[0020] The first step involves taking 20 mL of the uranium-containing mixed organic solvent to be treated at room temperature and mixing it thoroughly with 12.5 mol / L analytical grade phosphoric acid at a volume ratio of 1:1.5 for 8 minutes. The separation process is performed in four stages, and the reaction is allowed to stand at 25°C. After standing, the lower liquid phase is collected, yielding an H3PO4·nTBP solution, while the upper liquid phase is hydrogenated kerosene. At this point, the hydrogenated kerosene content in the upper liquid after separation can reach over 97%.

[0021] The second step involves adding 2.5 mol / L nitric acid aqueous solution to the obtained H3PO4·nTBP solution, with a two-phase flow ratio of 1:1.5 and a separation stage of 2. The reaction is allowed to stand at 25°C, and the supernatant is taken as the TBP product solution, thus achieving separation.

[0022] The third step involves preparing an extractant using the separated TBP and hydrogenated kerosene, and conducting a comparative experiment with the fresh extractant. The results show that the extraction effect of the TBP is close to that of the fresh extractant, thus meeting the process requirements.

[0023] Example 3:

[0024] The first step involves taking 20 mL of the uranium-containing mixed organic solvent to be treated at room temperature and mixing it thoroughly with 14.5 mol / L analytical grade phosphoric acid at a volume ratio of 1:2 for 10 min. The separation process is performed in five stages, and the reaction is allowed to stand at 30°C. After standing, the lower liquid phase is collected, yielding an H3PO4·nTBP solution, while the upper liquid phase is hydrogenated kerosene. At this point, the hydrogenated kerosene content in the upper liquid after separation can reach over 97%.

[0025] The second step involves adding 3 mol / L nitric acid aqueous solution to the obtained H3PO4·nTBP solution, with a two-phase flow ratio of 1:2 and a separation stage of 3. The reaction is allowed to stand at 30°C, and the supernatant is taken as the TBP product solution, thus achieving separation.

[0026] The third step involves preparing an extractant using the separated TBP and hydrogenated kerosene, and conducting a comparative experiment with the fresh extractant. The results show that the extraction effect of the TBP is close to that of the fresh extractant, thus meeting the process requirements.

[0027] The above description is merely a preferred embodiment of this patent and is not intended to limit this patent. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this patent shall be included within the scope of protection of this patent.

[0028] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0029] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0030] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to better understand and utilize this application.

Claims

1. A method for separating hydrogenated kerosene and TBP in a natural uranium extractant, characterized in that: Includes the following steps: The first step is to take 20 mL of the uranium-containing mixed organic solvent to be treated at room temperature and mix it thoroughly with 11-14.5 mol / L analytical grade phosphoric acid. After standing, the lower liquid phase is taken to obtain H3PO4•nTBP solution. The reaction of uranium-containing mixed organic solvents with phosphoric acid produces separation stages ranging from 1 to 5. The uranium-containing mixed organic solvent and phosphoric acid are mixed in a volume ratio of 1:1 to 1:

2. The mixture of uranium-containing organic solvent and phosphoric acid reacts for 5–10 minutes. The reaction was allowed to stand at 20–30°C. The upper liquid phase is hydrogenated kerosene; The second step involves adding 2–3 mol / L nitric acid aqueous solution to the obtained H3PO4•nTBP solution, allowing the reaction to stand, and then taking the supernatant as the TBP product solution to achieve separation. The two-phase flow ratio of H3PO4•nTBP solution to nitric acid aqueous solution is 1:1 to 1:2; The separation stages between H3PO4•nTBP solution and nitric acid aqueous solution are 2 to 3. The reaction was allowed to stand at 20–30°C. The third step involves preparing an extractant using the TBP obtained in the second step and hydrogenated kerosene, and then conducting a comparative experiment with the fresh extractant.

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