Multi-resin coupling purification and uranium recovery system and method for uranium-containing waste liquid

Abstract

According to the multi-resin coupling purification and uranium recovery system and method for the uranium-containing waste liquid, high-concentration uranium-containing waste liquid and low-concentration uranium-containing waste liquid generated by a uranium conversion production line are subjected to front-end classification treatment and rear-end unified treatment, waste liquid treatment and uranium recovery are finally achieved, and the uranium component in the waste liquid is recovered in the form of sodium diuranate. According to the method, the waste liquid of different source phases is subjected to front-end classification treatment by adopting ion exchange, alkali precipitation and other methods, so that the conditions that resin is easy to saturate and frequent analysis is needed due to the adoption of a single ion exchange technology are avoided. The conditions of high sodium hydroxide consumption and high operation cost caused by the need of a large amount of sodium hydroxide to adjust the pH value of the waste liquid by adopting a single alkali precipitation technology are avoided.

Description

Technical Field

[0001] This patent relates to the field of wastewater treatment technology, and specifically to a multi-resin coupled purification and uranium recovery system and method for uranium-containing waste liquid. Background Art

[0002] Uranium conversion is an important part of the nuclear fuel cycle. During its production process, a large amount of uranium-containing waste liquid is generated, including UF4 fluorinated tail gas eluent, exhaust purification eluent, cleaning waste liquid, analytical waste liquid, etc. These uranium-containing waste liquids are radioactive and have heavy metal toxicity. Leakage into the environment will cause serious pollution and human harm. Therefore, using appropriate processes to treat uranium-containing waste liquids is a basic requirement for environmental protection and life and health protection. At the same time, uranium is also an important strategic resource. Recycling and storing uranium-containing waste liquid as a secondary uranium resource is the preferred method to achieve harmless and resource-based treatment of uranium-containing wastewater.

[0003] At present, the uranium-containing wastewater treatment technologies used at home and abroad include chemical precipitation, ion exchange, membrane separation, adsorption, microbial method, etc. The chemical precipitation method has a good effect on treating high-concentration uranium-containing wastewater, but the treated wastewater still does not meet the discharge standard. The ion exchange method is suitable for low-concentration uranium-containing wastewater. Excessive uranium concentration consumes a large amount of ion exchange materials. The membrane separation method can efficiently remove uranium ions, but this method has problems such as easy membrane contamination and blockage and low permeation flux. The uranium concentration of some uranium-containing wastewater (UF4 fluorination tail gas eluent) generated in the uranium conversion process is as high as about 4g / L, and the uranium concentration of another part of the uranium-containing wastewater (exhaust purification eluent, cleaning wastewater, analytical wastewater) is relatively low, about 400mg / L. The use of a single alkaline precipitation technology to treat various types of wastewater generated by the uranium conversion plant will result in a high amount of sodium hydroxide addition and increased operating costs. The use of a single ion exchange technology will cause the resin to be easily saturated and require frequent analysis. The commonly used 201×7 ion exchange resin has a higher uranium adsorption saturation capacity, but the uranium content in the adsorption tail water cannot be treated to 50μg / L. After the TP260 and TP107 ion exchange resins treat the wastewater, the uranium content in the adsorption tail water can be reduced to below 50μg / L, but its adsorption saturation capacity is small and it is easy to saturate.

[0004] Therefore, this patent provides a process for waste liquid treatment and uranium recovery for uranium-containing and fluorine-containing waste liquid generated during the uranium conversion process. The high-concentration uranium-containing waste liquid and low-concentration uranium-containing waste liquid are subjected to front-end classification treatment. The uranium content of high-concentration uranium-containing waste liquid (about 4g / L) is reduced to 30mg / L through alkaline precipitation, flocculation sedimentation and other technologies. The main component of low-concentration uranium-containing waste liquid (about 400mg / L) is uranyl carbonate anion. The uranium content of the tail water is about 2mg / L after adsorption by 201×7 ion exchange resin. The wastewater is separated and treated at the front end and combined at the back end for treatment. and The anion complex formed by the TP260 ion exchange resin further adsorbs the remaining uranyl cations in the waste liquid. The uranium content in the treated tail water can be reduced to 50μg / L. The analyte after resin adsorption is saturated is returned to the front-end alkaline precipitation treatment to recover uranium in the form of sodium diuranate. Summary of the invention

[0005] The purpose of the present invention is to provide a multi-resin coupled purification and uranium recovery process for uranium-containing waste liquid. High-concentration uranium-containing waste liquid and low-concentration uranium-containing waste liquid generated by a uranium conversion production line are classified and processed at the front end and uniformly processed at the back end, thereby finally realizing the treatment of waste liquid and the recovery of uranium, so that the uranium component in the waste liquid is recovered in the form of sodium diuranate, and the uranium concentration of the treated waste liquid can be reduced to [U] <50μg / L.

[0006] The scheme of the present invention is: a multi-resin coupling purification and uranium recovery system for uranium-containing waste liquid, comprising a sedimentation tank, an overflow mixing tank, a 201×7 anion resin tower, a waste liquid receiving tank, an alkalization tank, an acidification tank, a TP260 cation exchange column, a TP107 anion exchange column, and an alkalization flocculation tank; the sedimentation tank is connected to the overflow mixing tank, the overflow mixing tank is connected to the 201×7 anion resin tower, the 201×7 anion resin tower is connected to the alkalization tank, the waste liquid receiving tank is connected to the alkalization tank, the alkalization tank is connected to the acidification tank, and the acidification tank is connected to the alkalization flocculation tank; the 201×7 anion resin tower and the alkalization flocculation tank are connected to the TP260 cation exchange column, and the TP260 cation exchange column is connected to the TP107 anion exchange column;

[0007] TP260 cation exchange column and TP107 anion exchange column both have a pre-adjustment tank.

[0008] A multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid comprises the following steps:

[0009] S1: Low-concentration uranium-containing waste liquid with a uranium concentration of less than 400 mg / L is received by the sedimentation tank, and the low-concentration uranium-containing waste liquid naturally settles in the sedimentation tank, and the supernatant overflows to the overflow blending tank; the waste liquid in the overflow blending tank is adjusted to pH 7-11. After adjustment, it is sent to the 201×7 anion resin tower for adsorption to recover uranium; adsorbent is added to the 201×7 anion resin tower;

[0010] The adsorption tail water of the 201×7 anion resin tower is tested. If the uranium concentration is less than 2 mg / L, it is sent to the pre-adjustment tank of the TP260 cation exchange column. If the uranium concentration of 1g / L is ≥2 mg / L, it is sent back to the 201×7 anion resin tower for adsorption again; if the uranium concentration is greater than 1g / L, it is sent to the alkalization tank;

[0011] S2: The high-concentration uranium-containing waste liquid with a uranium concentration greater than 1g / L is sent to the alkalization tank after passing through the waste liquid receiving tank, where it reacts with a 30% NaOH solution to generate an insoluble sodium diuranate precipitate, and the pH is adjusted to 9-11; the supernatant in the alkalization tank is sent to the acidification tank, 10% H2SO4 is added, the pH is adjusted to 3-5, and the waste liquid is removed.

[0012] The supernatant in the acidification tank overflows into the alkalinization flocculation tank, and 30% NaOH, 38% FeCl3, and PAM flocculant are added for alkalinization flocculation and sedimentation treatment. The supernatant in the alkalinization flocculation tank overflows into the pre-adjustment tank of the TP260 cation exchange column.

[0013] S3: The waste liquid generated after treatment by S1 is mixed with the waste liquid generated after treatment by S2 in the pre-preparation tank of the TP260 cation exchange column; then it is sent to the TP260 cation exchange column for exchange reaction to adsorb the uranium therein, and the adsorbed tail water enters the pre-preparation tank of the TP107 anion exchange column for mixing, and then it is sent to the TP107 anion exchange column for adsorption.

[0014] In S1, 30% NaOH solution is used to adjust the pH.

[0015] In S1, the water inlet flow rate is controlled to be 0.5-3m 3 / h

[0016] In the S1, the adsorbent is a mixed solution of 5% sodium carbonate and 8% sodium chloride.

[0017] In S1, the sedimentation liquid at the bottom of the sedimentation tank is regularly sent to the filter press for filtration, the filtrate is returned to the waste liquid receiving sedimentation tank for re-sedimentation, and the filter cake is collected and temporarily stored.

[0018] In S2, the precipitate in the alkalization tank is transported to the filter press by a pneumatic pump for filtration, and the filter cake is collected and temporarily stored as the nuclear material.

[0019] In S2, the precipitate in the alkalization flocculation tank is subjected to filter press treatment.

[0020] In S3, the water inlet flow rate is controlled to be 1 to 3 m 3 / h.

[0021] In S3, the adsorption tail water of the TP107 anion exchange column is tested, and if the uranium content of the tail water is less than 50 μg / L, it is discharged, otherwise the waste water returns to the TP107 anion exchange column for adsorption again.

[0022] The remarkable effects of the present invention are:

[0023] (1) The present invention provides a method for recovering uranium from uranium-containing and fluorine-containing waste liquid in a uranium conversion process. In view of the complex source of waste liquid in the uranium conversion system, the waste liquid of different source phases is subjected to front-end classification treatment by using methods such as ion exchange and alkaline precipitation, thereby avoiding the situation in which the resin is easily saturated and frequent analysis is required due to the use of a single ion exchange technology. It also avoids the situation in which a large amount of sodium hydroxide is required to adjust the pH value of the waste liquid due to the use of a single alkaline precipitation technology, resulting in a large amount of sodium hydroxide used and high operating costs. The uranium content of the waste liquid after front-end classification treatment can be reduced to 2-30 mg / L.

[0024] (2) The present invention provides a uranium recovery method for uranium-containing and fluorine-containing waste liquid in a uranium conversion process, which uses 201×7 resin to treat uranium-containing waste liquid with a low uranium concentration ([U]<400 mg / L) by ion exchange, and treats uranium-containing waste liquid with a high uranium concentration ([U]≈4 g / L) by alkali precipitation, thereby achieving continuous and stable operation of the process and reducing the operating cost of uranium conversion waste liquid treatment.

[0025] (3) The present invention provides a method for recovering uranium from uranium-containing and fluorine-containing waste liquid in a uranium conversion process. The uranium content of the waste liquid after front-end treatment is about 2 to 30 mg / L. After adsorption by TP260 cation exchange resin and TP107 anion exchange resin at the back end, the outlet tail water [U] is less than 50 μg / L, and the uranium recovery is ≥ 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid;

[0027] In the figure: sedimentation tank 1, overflow blending tank 2, 201×7 anion resin tower 3, waste liquid receiving tank 4, alkalization tank 5, acidification tank 6, TP260 cation exchange column 7, TP107 anion exchange column 8 DETAILED DESCRIPTION

[0028] Many specific details are described in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific implementation disclosed below.

[0029] The terms used in one or more embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit one or more embodiments of the present application. The singular forms of "a", "said" and "the" used in one or more embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in one or more embodiments of the present application refers to and includes any or all possible combinations of one or more associated listed items.

[0030] It should be understood that, although the terms first, second, etc. may be used to describe various information in one or more embodiments of the present application, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of the present application, the first may also be referred to as the second, and similarly, the second may also be referred to as the first.

[0031] A multi-resin coupling purification and uranium recovery system for uranium-containing waste liquid, comprising a sedimentation tank 1, an overflow mixing tank 2, a 201×7 anion resin tower 3, a waste liquid receiving tank 4, an alkalization tank 5, an acidification tank 6, a TP260 cation exchange column 7, a TP107 anion exchange column 8, and an alkalization flocculation tank 9; the sedimentation tank 1 is connected to the overflow mixing tank 2, the overflow mixing tank 2 is connected to the 201×7 anion resin tower 3, the 201×7 anion resin tower 3 is connected to the alkalization tank 5, the waste liquid receiving tank 4 is connected to the alkalization tank 5, the alkalization tank 5 is connected to the acidification tank 6, and the acidification tank 6 is connected to the alkalization flocculation tank 9; the 201×7 anion resin tower 3 and the alkalization flocculation tank 9 are connected to the TP260 cation exchange column 7, and the TP260 cation exchange column 7 is connected to the TP107 anion exchange column 8;

[0032] The TP260 cation exchange column 7 and the TP107 anion exchange column 8 both have a pre-adjustment tank;

[0033] A multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid comprises the following steps:

[0034] S1: Low-concentration uranium-containing waste liquid (uranium concentration is less than 400 mg / L) is received by sedimentation tank 1. The low-concentration uranium-containing waste liquid settles naturally in sedimentation tank 1, and the supernatant overflows to overflow blending tank 2. The waste liquid in overflow blending tank 2 is pH-adjusted with 30% NaOH solution to 7-11. After adjustment, the inlet flow rate is controlled to 0.5-3m 3 / h, and is pumped into a 201×7 anion resin tower 3 for adsorption to recover uranium; an adsorbent is added to the 201×7 anion resin tower 3, and the adsorbent is a mixed solution of 5% sodium carbonate and 8% sodium chloride;

[0035] The adsorption tail water of the 201×7 anion resin tower 3 is tested. If the uranium concentration is less than 2 mg / L, it is sent to the pre-adjustment tank of the TP260 cation exchange column 7. If the uranium concentration of 1 g / L is ≥ 2 mg / L, it is sent back to the 201×7 anion resin tower 3 for adsorption again; if the uranium concentration is greater than 1 g / L, it is sent to the alkalization tank 5;

[0036] The sedimentation liquid at the bottom of the sedimentation tank 1 is regularly sent to the filter press for filtration, and the filtrate is returned to the waste liquid receiving sedimentation tank 1 for re-sedimentation, and the filter cake is collected and temporarily stored.

[0037] S2: High-concentration uranium-containing waste liquid (uranium concentration greater than 1g / L) is sent to the alkalization tank 5 after passing through the waste liquid receiving tank 4, where it reacts with a 30% NaOH solution to generate an insoluble sodium diuranate precipitate, and the pH is adjusted to 9-11. The precipitate in the alkalization tank 5 is transported to the filter press by a pneumatic pump for filtration, and the filter cake is collected and temporarily stored as nuclear material. The supernatant in the alkalization tank 5 is sent to the acidification tank 6, where 10% H2SO4 is added to adjust the pH to 3-5 to remove the waste liquid.

[0038] The supernatant in the acidification tank 6 overflows into the alkalization flocculation tank 9, and 30% NaOH, 38% FeCl3, and PAM flocculant are added for alkalization flocculation sedimentation treatment. The precipitate in the alkalization flocculation tank 9 is subjected to filter press treatment, and the supernatant overflows into the pre-adjustment tank of the TP260 cation exchange column 7.

[0039] S3: The waste liquid produced after the treatment of S1 is mixed with the waste liquid produced after the treatment of S2 in the pre-adjustment tank of TP260 cation exchange column 7; then it is sent to TP260 cation exchange column 7 for exchange reaction to adsorb the uranium therein, and the water inlet flow rate is controlled to be 1-3m 3 / h, through the TP260 cation exchange column 7 adsorption, the adsorption tail water enters the front preparation tank of the TP107 anion exchange column 8 for mixing, and then sent to the TP107 anion exchange column 8, and the water inlet flow rate is controlled to 1-3m 3 / h.

[0040] The adsorption tail water of TP107 anion exchange column 8 is tested. If the uranium content of the tail water is less than 50 μg / L, it is discharged. Otherwise, the waste liquid returns to TP107 anion exchange column 8 for adsorption again.

[0041] The above description is only 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 should be included in the scope of protection of this patent.

[0042] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described action sequence, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0043] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0044] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The optional embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of the present application. The present application selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can understand and use the present application well.

Claims

1. A multi-resin coupled purification and uranium recovery system for uranium-containing waste liquid, characterized in that: The invention comprises a sedimentation tank (1), an overflow mixing tank (2), a 201×7 anion resin tower (3), a waste liquid receiving tank (4), an alkalization tank (5), an acidification tank (6), a TP260 cation exchange column (7), a TP107 anion exchange column (8), and an alkalization flocculation tank (9); the sedimentation tank (1) is connected to the overflow mixing tank (2), the overflow mixing tank (2) is connected to the 201×7 anion resin tower (3), the 201×7 anion resin tower (3) is connected to the alkalization tank (5), the waste liquid receiving tank (4) is connected to the alkalization tank (5), the alkalization tank (5) is connected to the acidification tank (6), and the acidification tank (6) is connected to the alkalization flocculation tank (9); the 201×7 anion resin tower (3) and the alkalization flocculation tank (9) are connected to the TP260 cation exchange column (7), and the TP260 cation exchange column (7) is connected to the TP107 anion exchange column (8); Both the TP260 cation exchange column (7) and the TP107 anion exchange column (8) have a pre-adjustment tank.

2. A multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid, using the multi-resin coupled purification and uranium recovery system for uranium-containing waste liquid as claimed in claim 1, characterized in that: The following steps are involved: S1: low-concentration uranium-containing waste liquid with a uranium concentration of less than 400 mg / L is received by a sedimentation tank (1), the low-concentration uranium-containing waste liquid naturally settles in the sedimentation tank (1), and the supernatant overflows to the overflow blending tank (2); the waste liquid in the overflow blending tank (2) is adjusted to a pH of 7 to 11; after adjustment, it is sent to a 201×7 anion resin tower (3) for adsorption to recover uranium; an adsorbent is added to the 201×7 anion resin tower (3); The adsorption tail water of the 201×7 anion resin tower (3) is tested. If the uranium concentration is less than 2 mg / L, it is sent to the pre-adjustment tank of the TP260 cation exchange column (7). If the uranium concentration is 1 g / L or more than 2 mg / L, it is sent back to the 201×7 anion resin tower (3) for adsorption again. If the uranium concentration is greater than 1 g / L, it is sent to the alkalization tank (5). S2: The high-concentration uranium-containing waste liquid with a uranium concentration greater than 1g / L is sent to the alkalization tank (5) after passing through the waste liquid receiving tank (4), where it reacts with a 30% NaOH solution to generate an insoluble sodium diuranate precipitate, and the pH is adjusted to 9-11; the supernatant in the alkalization tank (5) is sent to the acidification tank (6), where 10% H2SO4 is added to adjust the pH to 3-5, and the waste liquid is removed. The supernatant in the acidification tank (6) overflows into the alkalinization flocculation tank (9), and 30% NaOH, 38% FeCl3, and PAM flocculant are added to perform alkalinization flocculation sedimentation treatment. The supernatant in the alkalinization flocculation tank (9) overflows into the pre-adjustment tank of the TP260 cation exchange column (7); S3: The waste liquid generated after the treatment of S1 and the waste liquid generated after the treatment of S2 are mixed in the pre-adjustment tank of the TP260 cation exchange column (7); then sent to the TP260 cation exchange column (7) for exchange reaction to adsorb the uranium therein, and the adsorbed tail water is adsorbed by the TP260 cation exchange column (7), and then sent to the TP107 anion exchange column (8) for adsorption.

3. The multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid according to claim 2, characterized in that: In S1, 30% NaOH solution is used to adjust the pH.

4. The multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid according to claim 2, characterized in that: In S1, the water inlet flow rate is controlled to be 0.5-3m 3 / h.

5. The multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid according to claim 2, characterized in that: In the S1, the adsorbent is a mixed solution of 5% sodium carbonate and 8% sodium chloride.

6. The multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid according to claim 2, characterized in that: In S1, the sedimentation liquid at the bottom of the sedimentation tank (1) is regularly sent to a filter press for filtration, the filtrate is returned to the waste liquid receiving sedimentation tank (1) for re-sedimentation, and the filter cake is collected and temporarily stored.

7. The multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid according to claim 2, characterized in that: In S2, the precipitate in the alkalization tank (5) is transported to the filter press by a pneumatic pump for filtration, and the filter cake is collected and temporarily stored as the nuclear material.

8. The multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid according to claim 2, characterized in that: In S2, the precipitate in the alkalization flocculation tank (9) is subjected to filter press treatment.

9. The multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid according to claim 2, characterized in that: In S3, the water inlet flow rate is controlled to be 1 to 3 m 3 / h.

10. The multi-resin coupled purification and uranium recovery method for uranium-containing waste liquid according to claim 2, characterized in that: In the above S3, the adsorption tail water of the TP107 anion exchange column (8) is tested, and if the uranium content of the tail water is less than 50 μg / L, it is discharged, otherwise the waste water is returned to the TP107 anion exchange column (8) for adsorption again.

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