Uranium extraction resin regeneration method

Abstract

The invention discloses a uranium extraction resin regeneration method which comprises the following steps: 1) adding disodium ethylene diamine tetraacetate into an alkaline solution with OH <-> concentration of 1-2.5 mol / L, and uniformly mixing to obtain a regeneration solution; the concentration of disodium ethylene diamine tetraacetate in the regeneration solution is 5-20 g / L; (2) loading uranium extraction resin to be treated into regeneration equipment to form a resin bed layer; and enabling the regeneration solution to pass through a resin bed layer at the flow speed of 2BV / h to 10BV / h, and regenerating the uranium extraction resin to be treated. According to the method, the ethylene diamine tetraacetic acid is added into the aqueous alkali, and the characteristic that the ethylene diamine tetraacetic acid and impurities such as calcium sulfate / magnesium sulfate form a stable soluble complex is utilized, so that the capacity of dissolving precipitates on the surface of the resin is remarkably improved, and compared with a traditional method only using the aqueous alkali, the resin regeneration efficiency is improved by 30-50%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of hydrometallurgy, and particularly relates to a method for regenerating uranium extraction resin. BACKGROUND

[0002] Uranium is an important strategic metal with high melting point, high strength and good plasticity, and is widely used in modern high-tech fields such as national defense, aerospace, nuclear energy and the like. At present, acid leaching is the main method for exploiting permeable sandstone uranium deposits, and this method is widely used in the world's in-situ leaching uranium mines due to the advantages of high leaching strength, short production time of the mining area and high leaching rate.

[0003] In the hydrometallurgical process, uranium extraction resin is a key tool for separating and recovering uranium. However, in actual application, a large amount of iron, potassium, calcium, magnesium, aluminum and silicon ions are contained in the uranium solution, and impurity cations are co-precipitated for a long time, forming substances such as iron hydroxide, calcium sulfate, magnesium sulfate and silica gel attached to the surface of the resin, resulting in the hardening of the resin. Ion exchange combined with solvent extraction is a common uranium extraction process, and in this process, part of the raffinate after solvent extraction is generally returned to the front end as an acid solution for resin elution, and the organic extractant is easily attached to the surface of the resin, further polluting the resin and affecting the exchange capacity and service life of the resin.

[0004] At present, the treatment of uranium extraction resin with an alkaline solution is a method that can elute the organic matter and impurity cation co-precipitates on the surface of the resin, restore the adsorption performance of the resin and improve the recovery efficiency of uranium. However, when only an alkaline solution is used as a regenerating agent, the consumption of the alkaline solution is large, and the impurity cation co-precipitates are easily coated on the surface of the resin. The alkaline soaking cannot completely dissolve the large particles, and the regeneration effect of the resin is poor. Therefore, it is urgent to develop a high-efficiency method for regenerating uranium extraction resin, which can remove the organic matter and impurity cation co-precipitates on the surface of the resin at the same time, and ensure the smooth progress of the uranium extraction process of sulfuric acid leaching of uranium ore. SUMMARY

[0005] In order to solve the problems that the uranium extraction resin is coated with impurity precipitates such as iron hydroxide, calcium sulfate, magnesium sulfate and silica gel during use, resulting in the hardening of the resin, and the organic extractant is attached to and pollutes the resin, and to achieve the technical effects of improving the regeneration efficiency of the uranium extraction resin and effectively removing the pollutants on the surface of the resin, the present application provides a method for regenerating uranium extraction resin under alkaline conditions.

[0006] A method for regenerating uranium extraction resin, comprising the following steps:

[0007] Step 1) adding ethylenediaminetetraacetic acid disodium into an alkaline solution with a concentration of 1-2.5 mol / L and mixing uniformly to obtain a regeneration solution; the concentration of ethylenediaminetetraacetic acid disodium in the regeneration solution is 5-20 g / L; - Step 2) adding the regeneration solution into the uranium extraction resin, and soaking for 1-3 hours; and Step 3) washing the uranium extraction resin with water, and then drying.

[0008] Step two) loading the uranium extraction resin to be treated into a regeneration device to form a resin bed; and passing the regeneration solution through the resin bed at a flow rate of 2-10 BV / h to regenerate the uranium extraction resin to be treated.

[0009] Optionally, the alkaline solution is a sodium hydroxide or potassium hydroxide solution.

[0010] Optionally, in step two, the regeneration solution is passed through the resin bed at a flow rate of 2-10 BV / h at a temperature of 20-60°C for 1-4 hours.

[0011] Optionally, in step two), the uranium extraction resin to be treated is first pretreated and then loaded into the regeneration device.

[0012] The pretreatment comprises: rinsing the uranium extraction resin to be treated with water, soaking the rinsed uranium extraction resin to be treated in water until the uranium extraction resin to be treated is fully expanded, and then filtering.

[0013] Optionally, the pretreatment comprises rinsing the uranium extraction resin to be treated with water for 2-5 times, soaking the rinsed uranium extraction resin to be treated in water for 20-40 min until the uranium extraction resin to be treated is fully expanded, and then filtering.

[0014] Optionally, during the column loading process, the ratio of the diameter to the height of the resin bed is 1:2-1:15.

[0015] Optionally, during the column loading process, the height of the resin bed is 3-3.5 m and the diameter is 1-1.2 m.

[0016] Optionally, in step two), the uranium extraction resin to be treated is regenerated and then rinsed.

[0017] Optionally, the rinsing step comprises: rinsing the resin bed with water at a flow rate of 2-10 BV / h for 1-4 hours until the pH value of the effluent is neutral; and then taking out the resin and soaking it in deionized water for 1-2 hours.

[0018] Optionally, the uranium extraction resin is a strong alkaline anion exchange resin.

[0019] Compared with the prior art, the present application has the following outstanding advantages:

[0020] The present application can significantly improve the dissolution capacity of the precipitate on the resin surface by adding disodium ethylenediaminetetraacetate in the alkali solution, using the characteristic of forming stable soluble complex with impurities such as calcium sulfate / magnesium sulfate, etc., and the resin regeneration efficiency is increased by 30-50% compared with the traditional method using only alkali solution.

[0021] The method of the present application can effectively solve the problem of the uranium extraction resin being covered by precipitate, especially for the impurity precipitate of iron hydroxide, calcium sulfate, magnesium sulfate and silica gel generated during long-term operation, and the removal rate can reach more than 85%. The method of the present application can also effectively remove the organic extractant attached to the surface of the resin, reduce the loss of exchange capacity of the resin, and prolong the service life of the resin. The exchange capacity of the resin treated by the method can be restored to more than 90% of that of new resin.

[0022] The method of the present application is simple to operate, has good compatibility with the existing process, does not need to increase additional equipment, and can be directly applied to the existing uranium extraction process, and has good practicability and economy. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0024] Figure 1 The scanning electron microscope image of the uranium extraction resin before regeneration.

[0025] Figure 2 The scanning electron microscope image of the uranium extraction resin after regeneration in Example 1. DETAILED DESCRIPTION

[0026] Now, various exemplary embodiments of the present application will be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of some aspects, characteristics and embodiments of the present application. It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the present application.

[0027] In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the stated range, and any other stated value or intermediate value in the stated range is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0028] Unless otherwise indicated, all technical and scientific terms have the same meaning as those one of ordinary skill in the art of the invention would understand. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. OH

[0029] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended terms that are intended to mean one or more, but not excluding additional, elements.

[0030] The present application provides a method for regenerating uranium extraction resin, comprising the following steps:

[0031] Step one) adding ethylenediaminetetraacetic acid disodium to an alkaline solution with a concentration of 1-2.5 mol / L and mixing uniformly to obtain a regeneration solution; the concentration of ethylenediaminetetraacetic acid disodium in the regeneration solution is 5-20 g / L; - adding ethylenediaminetetraacetic acid disodium to an alkaline solution with a concentration of 1-2.5 mol / L and mixing uniformly to obtain a regeneration solution; the concentration of ethylenediaminetetraacetic acid disodium in the regeneration solution is 5-20 g / L;

[0032] Step two) loading the uranium extraction resin to be treated into a regeneration device to form a resin bed layer; passing the regeneration solution through the resin bed layer at a flow rate of 2-10 BV / h to regenerate the uranium extraction resin to be treated.

[0033] The alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution.

[0034] Further, in step two), the regeneration solution is passed through the resin bed layer at a flow rate of 2-10 BV / h at a temperature of 20-60°C for 1-4 hours.

[0035] Further, in step two), the uranium extraction resin to be treated is pretreated before being loaded into the regeneration device.

[0036] The pretreatment includes: flushing the uranium extraction resin to be treated with water, soaking the flushed uranium extraction resin to be treated in water until the uranium extraction resin to be treated is fully swollen, and then filtering.

[0037] Further, in step two), the uranium extraction resin to be treated is regenerated, and then the resin is flushed.

[0038] Further, the step of flushing the resin includes: flushing the resin bed layer with water at a flow rate of 2-10 BV / h for 1-4 hours until the pH value of the effluent decreases to neutral; and then taking out the resin and soaking it in deionized water for 1-2 hours.

[0039] The present application significantly improves the dissolution capacity of the precipitates on the resin surface by adding disodium ethylenediaminetetraacetate in an alkali solution, using the characteristics of forming stable soluble complexes with impurities such as calcium sulfate / magnesium sulfate. The method of the present application can effectively solve the problem of uranium extraction resin being covered by precipitates, especially for the impurity precipitates of iron hydroxide, calcium sulfate, magnesium sulfate and silica gel generated during long-term operation. The method of the present application can also effectively remove the organic extractant attached to the surface of the resin, reduce the loss of exchange capacity of the resin, and prolong the service life of the resin.

[0040] The uranium extraction resin to be treated used in the following examples and comparative examples is sampled from the on-site production of uranium extraction resin in Hushan Mine of China Guangdong Nuclear Skour Industry, and the resin model is: Xi'an Lanxiao Science and Technology New Material Co., Ltd.

[0041] The LXA-800 resin product is a strong alkaline anion exchange resin.

[0042] Example 1

[0043] A novel method for regenerating uranium extraction resin under alkaline conditions, comprising the following steps:

[0044] Step one: preparation work;

[0045] Prepare the uranium extraction resin, which is a strong alkaline anion exchange resin; prepare an alkali solution, which is a sodium hydroxide solution with a concentration of 1 mol / L; and prepare disodium ethylenediaminetetraacetate (EDTA-2Na) solid.

[0046] Step two: pretreatment of uranium extraction resin;

[0047] Collect the used uranium extraction resin, rinse it with deionized water for 3 times, each time for 5 minutes, to remove the impurities attached to the surface of the resin; place the rinsed resin in a beaker, add deionized water to soak for 30 minutes, so that the resin is fully swollen; filter and collect the resin for use.

[0048] Step three: adding disodium ethylenediaminetetraacetate in the alkali solution;

[0049] Add disodium ethylenediaminetetraacetate to the prepared sodium hydroxide solution, and the amount of addition is 20g of disodium ethylenediaminetetraacetate per liter of alkali solution; under room temperature (25℃) conditions, stir for 10 minutes to make the disodium ethylenediaminetetraacetate fully dissolved, forming a complexing agent enhanced alkali solution.

[0050] Step four: alkaline regeneration of uranium extraction resin;

[0051] The pretreated uranium extraction resin is placed in a glass column with a height of 38 cm and an inner diameter of 3 cm; the complexing agent enhanced alkali solution prepared in step three is passed through the resin bed at a flow rate of 2 BV / h (bed volume / hour); the temperature is controlled at 30 DEG C during the regeneration process, and the regeneration time is 4 hours; during this process, the disodium ethylenediaminetetraacetate forms soluble complexes with the impurities such as calcium sulfate and magnesium sulfate on the surface and inside of the resin, promotes the dissolution of the impurity precipitates, and effectively solves the problem of the uranium extraction resin being coated by the precipitates.

[0052] Step five: post-treatment after regeneration;

[0053] After the regeneration is completed, the resin is washed with deionized water at a flow rate of 5 BV / h for 2 hours until the pH value of the effluent decreases to neutral; the washed resin is taken out and soaked in deionized water for 1 hour; filtration is performed, and the regenerated resin is collected.

[0054] Step six: detection of the regeneration effect;

[0055] A small amount of the regenerated resin is taken to determine the exchange capacity by the acid-base titration method; the determination result shows that the exchange capacity of the resin after regeneration can be restored to more than 95% of that of the new resin, reaching more than 4.0 mmol / g; at the same time, the resin surface morphology is observed by scanning electron microscopy, as shown in FIGS. 1 and 2, and it is confirmed that the precipitates on the resin surface are effectively removed, and the resin pores are unobstructed. Figure 1 、 2

[0056] In this embodiment, the disodium ethylenediaminetetraacetate as a high-efficiency complexing agent can form stable soluble complexes with divalent metal ions such as calcium sulfate and magnesium sulfate. Under alkaline conditions, the complexing ability of the disodium ethylenediaminetetraacetate is further enhanced, and the precipitates on the surface and inside of the uranium extraction resin can be effectively dissolved. Compared with the traditional method of using only an alkali solution for regeneration, the present method can significantly improve the regeneration efficiency, prolong the service life of the resin, and reduce the operating cost.

[0057] Example 2: actual production application example

[0058] Step one: preparation of the alkali solution-disodium ethylenediaminetetraacetate mixed solution

[0059] An alkali solution is prepared, and the alkali solution is a sodium hydroxide solution with a concentration of 1 mol / L; 20 g of disodium ethylenediaminetetraacetate (EDTA-2Na) is added to each liter of the sodium hydroxide solution.

[0060] Step two: pretreatment of the uranium extraction resin

[0061] ​The used uranium extraction resin is loaded into a resin regeneration column, washed with deionized water until the effluent is clear; deionized water is injected into the regeneration column to fully expand the resin; the water in the column is emptied. The height of the resin bed in the regeneration column is 3.2 m, and the diameter is 1.1 m.

[0062] Step three: alkaline regeneration of the uranium extraction resin;

[0063] The complexing agent enhanced alkaline solution prepared in step one is passed through the resin bed at a flow rate of 2 BV / h (bed volume / hour); the temperature is controlled at 30°C during the regeneration process, and the regeneration time is 4 hours.

[0064] Step four: post-regeneration treatment;

[0065] After the regeneration is completed, the resin is washed with deionized water at a flow rate of 5 BV / h until the pH of the effluent decreases to neutral; the regenerated resin is collected after filtration.

[0066] Step six: detection of the regeneration effect;

[0067] A small amount of the regenerated resin is taken for exchange capacity determination, and the determination method is acid-base titration; the determination result shows that the exchange capacity of the regenerated resin is 4.0 mmol / g.

[0068] Example 3

[0069] Step one: preparation work;

[0070] The uranium extraction resin is prepared, which is a strong alkaline anion exchange resin; an alkaline solution is prepared, which is a sodium hydroxide solution with a concentration of 1 mol / L; and ethylenediaminetetraacetic acid disodium (EDTA-2Na) solid is prepared.

[0071] Step two: pretreatment of the uranium extraction resin;

[0072] The used uranium extraction resin is collected and washed with deionized water for 3 times, each time for 5 minutes, to remove impurities attached to the surface of the resin; the washed resin is placed in a beaker and soaked in deionized water for 30 minutes to fully expand the resin; the resin is collected after filtration for standby use.

[0073] Step three: addition of ethylenediaminetetraacetic acid disodium in the alkaline solution;

[0074] Ethylenediaminetetraacetic acid disodium is added to the prepared sodium hydroxide solution, and the amount of addition is 20 g of ethylenediaminetetraacetic acid disodium per liter of alkaline solution; under room temperature (25°C) conditions, stirring for 10 minutes to fully dissolve the ethylenediaminetetraacetic acid disodium, forming a complexing agent enhanced alkaline solution.

[0075] Step four: alkaline regeneration of the uranium extraction resin;

[0076] Two pretreated uranium extraction resins were taken respectively and placed in a glass column with a height of 38 cm and an inner diameter of 3 cm; the complexing agent enhanced alkali solution prepared in step three was passed through the resin bed layer at a flow rate of 5 BV / h (bed volume / hour); the temperature was controlled at 30°C during the regeneration process, and the regeneration time was 4 hours.

[0077] Step five: post-treatment after regeneration;

[0078] After the regeneration was completed, the resin was washed with deionized water at a flow rate of 5 BV / h for 2 hours until the pH value of the effluent decreased to neutral; the washed resin was taken out and soaked in deionized water for 1 hour; filtration was performed, and the regenerated resin was collected.

[0079] Step six: detection of the regeneration effect;

[0080] A small amount of the regenerated resin was taken and subjected to exchange capacity determination by acid-base titration method; the determination results showed that the exchange capacity of the resin regenerated at a flow rate of 5 BV / h was 4.01 mmol / g, which was 97% of the exchange capacity of the new resin.

[0081] Example 4

[0082] Step one: preparation work;

[0083] Uranium extraction resin was prepared, and the uranium extraction resin was a strong basic anion exchange resin; an alkali solution was prepared, and the alkali solution was a sodium hydroxide solution with a concentration of 1 mol / L; ethylenediaminetetraacetic acid disodium (EDTA-2Na) solid was prepared.

[0084] Step two: pretreatment of the uranium extraction resin;

[0085] The used uranium extraction resin was collected and washed with deionized water for 3 times, each time for 5 minutes, to remove impurities attached to the surface of the resin; the washed resin was placed in a beaker and soaked in deionized water for 30 minutes to fully swell the resin; filtration was performed, and the resin was collected for standby use.

[0086] Step three: addition of ethylenediaminetetraacetic acid disodium in the alkali solution;

[0087] Ethylenediaminetetraacetic acid disodium was added to the prepared sodium hydroxide solution, and the amount of addition was 20 g of ethylenediaminetetraacetic acid disodium per liter of alkali solution; under room temperature (25°C) conditions, stirring was performed for 10 minutes to fully dissolve the ethylenediaminetetraacetic acid disodium, forming a complexing agent enhanced alkali solution.

[0088] Step four: alkali regeneration of the uranium extraction resin;

[0089] Two pretreated uranium extraction resins were taken and placed in a glass column with a height of 38 cm and an inner diameter of 3 cm; the complexing agent enhanced alkali solution prepared in step three was passed through the resin bed at a flow rate of 10 BV / h (bed volume / hour); the temperature was controlled at 30°C during the regeneration process, and the regeneration time was 4 hours.

[0090] Step five: post-treatment after regeneration;

[0091] After the regeneration was completed, the resin was washed with deionized water at a flow rate of 5 BV / h for 2 hours until the pH value of the effluent decreased to neutral; the washed resin was taken out and soaked in deionized water for 1 hour; filtration was performed, and the regenerated resin was collected.

[0092] Step six: detection of the regeneration effect;

[0093] A small amount of the regenerated resin was taken and subjected to exchange capacity determination by acid-base titration; the determination results showed that the exchange capacity of the resin regenerated at a flow rate of 10 BV / h was 3.72 mmol / g, which was 90% of the exchange capacity of new resin. By appropriately reducing the flow rate, the alkali solution can fully enter the pore structure of the resin and combine with impurities, thereby improving the regeneration effect of the resin.

[0094] Example 5

[0095] Step one: preparation work;

[0096] Uranium extraction resin was prepared, and the uranium extraction resin was a strong basic anion exchange resin; an alkali solution was prepared, and the alkali solution was a potassium hydroxide solution with a concentration of 2.5 mol / L; and ethylenediaminetetraacetic acid disodium (EDTA-2Na) solid was prepared.

[0097] Step two: pretreatment of the uranium extraction resin;

[0098] The used uranium extraction resin was collected and washed with deionized water for 3 times, each time for 5 minutes, to remove impurities attached to the surface of the resin; the washed resin was placed in a beaker and soaked in deionized water for 30 minutes to fully swell the resin; filtration was performed, and the resin was collected for use.

[0099] Step three: addition of ethylenediaminetetraacetic acid disodium to the alkali solution;

[0100] Ethylenediaminetetraacetic acid disodium was added to the prepared potassium hydroxide solution, and the amount of addition was 20 g of ethylenediaminetetraacetic acid disodium per liter of alkali solution; under room temperature (25°C) conditions, the ethylenediaminetetraacetic acid disodium was stirred for 10 minutes to fully dissolve, forming a complexing agent enhanced alkali solution.

[0101] Step four: alkali regeneration of the uranium extraction resin;

[0102] Two pretreated uranium extraction resins were taken respectively and placed in a glass column with a height of 10 cm and an inner diameter of 5 cm; the complexing agent enhanced alkali solution prepared in step three was passed through the resin bed layer at a flow rate of 2 BV / h (bed volume / hour); the temperature was controlled at 30°C during the regeneration process, and the regeneration time was 4 hours.

[0103] Step five: post-treatment after regeneration;

[0104] After the regeneration was completed, the resin was washed with deionized water at a flow rate of 5 BV / h for 2 hours until the pH value of the effluent decreased to neutral; the washed resin was taken out and soaked in deionized water for 1 hour; filtration was performed, and the regenerated resin was collected.

[0105] Step six: detection of the regeneration effect;

[0106] A small amount of the regenerated resin was taken and subjected to exchange capacity determination by acid-base titration method; the determination result showed that the exchange capacity of the regenerated resin was 4.04 mmol / g, which was 98.5% of the exchange capacity of the new resin.

[0107] Example 6

[0108] Step one: preparation work;

[0109] Uranium extraction resin was prepared, and the uranium extraction resin was a strong basic anion exchange resin; an alkali solution was prepared, and the alkali solution was a potassium hydroxide solution with a concentration of 1 mol / L; ethylenediaminetetraacetic acid disodium (EDTA-2Na) solid was prepared.

[0110] Step two: pretreatment of the uranium extraction resin;

[0111] The used uranium extraction resin was collected and washed with deionized water for 3 times, each time for 5 minutes, to remove impurities attached to the surface of the resin; the washed resin was placed in a beaker and soaked in deionized water for 30 minutes to fully swell the resin; filtration was performed, and the resin was collected for use.

[0112] Step three: addition of ethylenediaminetetraacetic acid disodium in the alkali solution;

[0113] Ethylenediaminetetraacetic acid disodium was added to the prepared potassium hydroxide solution, and the amount of addition was 5 g of ethylenediaminetetraacetic acid disodium per liter of alkali solution; under room temperature (25°C) conditions, the ethylenediaminetetraacetic acid disodium was stirred for 10 minutes to fully dissolve and form a complexing agent enhanced alkali solution.

[0114] Step four: alkali regeneration of the uranium extraction resin;

[0115] Two pretreated uranium extraction resins were taken respectively and placed in a glass column with a height of 45 cm and an inner diameter of 3 cm; the complexing agent enhanced alkali solution prepared in step three was passed through the resin bed layer at a flow rate of 5 BV / h (bed volume / hour); the temperature was controlled at 30°C during the regeneration process, and the regeneration time was 4 hours.

[0116] Step five: post-treatment after regeneration;

[0117] After the regeneration was completed, the resin was washed with deionized water at a flow rate of 5 BV / h for 2 hours until the pH value of the effluent decreased to neutral; the washed resin was taken out and soaked in deionized water for 1 hour; filtration was performed, and the regenerated resin was collected.

[0118] Step six: detection of the regeneration effect;

[0119] A small amount of the regenerated resin was taken to determine the exchange capacity by acid-base titration method; the determination result showed that the exchange capacity of the regenerated resin was 3.8 mmol / g, which was 93% of the exchange capacity of the new resin.

[0120] Comparative example 1

[0121] Step one: preparation work;

[0122] The uranium extraction resin was prepared, and the uranium extraction resin was a strong basic anion exchange resin; the alkali solution was prepared, and the alkali solution was a sodium hydroxide solution with a concentration of 40 g / L.

[0123] Step two: pretreatment of the uranium extraction resin;

[0124] The used uranium extraction resin was collected and washed with deionized water for 3 times, each time for 5 minutes to remove the impurities attached to the surface of the resin; the washed resin was placed in a beaker and soaked in deionized water for 30 minutes to fully swell the resin; filtration was performed, and the resin was collected for use.

[0125] Step three: alkali regeneration of the uranium extraction resin;

[0126] The pretreated uranium extraction resin was placed in a glass column with a height of 38 cm and an inner diameter of 3 cm; the alkali solution prepared in step one was passed through the resin bed layer at a flow rate of 2 BV / h (bed volume / hour); the temperature was controlled at 30°C during the regeneration process, and the regeneration time was 4 hours.

[0127] Step four: post-treatment after regeneration;

[0128] After the regeneration was completed, the resin was washed with deionized water at a flow rate of 5 BV / h for 2 hours until the pH value of the effluent decreased to neutral; the washed resin was taken out and soaked in deionized water for 1 hour; filtration was performed, and the regenerated resin was collected.

[0129] Step five: Regeneration effect detection;

[0130] A small amount of the regenerated resin was taken for exchange capacity determination by acid-base titration method. The determination result showed that the exchange capacity of the regenerated resin was 2.72 mmol / g, which was 66% of the resin.

[0131] Comparative example 2

[0132] Step one: Preparation work;

[0133] The uranium extraction resin was prepared, which was a strong basic anion exchange resin. An ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) solution was prepared, and the concentration was 20 g / L.

[0134] Step two: Pretreatment of the uranium extraction resin;

[0135] The used uranium extraction resin was collected and washed with deionized water for 3 times, each time for 5 minutes to remove the impurities attached to the surface of the resin. The washed resin was placed in a beaker and soaked in deionized water for 30 minutes to fully swell the resin. The resin was collected by filtration for standby.

[0136] Step three: Alkaline regeneration of the uranium extraction resin;

[0137] The pretreated uranium extraction resin was placed in a glass column with a height of 38 cm and an inner diameter of 3 cm. The EDTA-2Na solution prepared in step one was passed through the resin bed at a flow rate of 2 BV / h (bed volume / hour). The temperature was controlled at 30°C during the regeneration process, and the regeneration time was 4 hours.

[0138] Step four: Post-regeneration treatment;

[0139] After the regeneration was completed, the resin was washed with deionized water at a flow rate of 5 BV / h for 2 hours until the pH value of the effluent decreased to neutral. The washed resin was taken out and soaked in deionized water for 1 hour. The regenerated resin was collected by filtration.

[0140] Step five: Regeneration effect detection;

[0141] A small amount of the regenerated resin was taken for exchange capacity determination by acid-base titration method. The determination result showed that the exchange capacity of the regenerated resin was 2.72 mmol / g, which was 66% of the resin.

[0142] Obviously, the above embodiments are merely example for clearly illustrating but not limitation to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments need not and can not be enumerated. The obvious changes or variations derived from the above description are still within the protection scope of the present application.

Claims

1. A method for regenerating a uranium extraction resin, characterized in that, The method comprises the following steps: Step one) to OH - The ethylenediaminetetraacetic acid disodium salt is added into the alkaline solution with the concentration of 1-2.5 mol / L and mixed uniformly to obtain a regeneration solution; the concentration of the ethylenediaminetetraacetic acid disodium salt in the regeneration solution is 5-20 g / L. Step 2) loading the uranium extraction resin to be treated into a regeneration device to form a resin bed layer; and passing the regeneration solution through the resin bed layer at a flow rate of 2-10 BV / h to regenerate the uranium extraction resin to be treated.

2. The method for regenerating the uranium extraction resin according to claim 1, characterized by, The alkaline solution is a sodium hydroxide or potassium hydroxide solution.

3. The method for regenerating the uranium extraction resin according to claim 1, characterized by, In step 2, the regeneration solution is passed through the resin bed layer at a flow rate of 2-10 BV / h at a temperature of 20-60°C for 1-4 hours.

4. The method of claim 1, wherein the uranium extraction resin is regenerated by, In step 2, the uranium extraction resin to be treated is pretreated before being loaded into the regeneration device. The pretreatment comprises washing the uranium extraction resin to be treated with water, soaking the washed uranium extraction resin to be treated in water until the uranium extraction resin to be treated is fully expanded, and then filtering.

5. The method for regenerating the uranium extraction resin according to claim 4, characterized by, The pretreatment comprises washing the uranium extraction resin to be treated with water for 2-5 times, soaking the washed uranium extraction resin to be treated in water for 20-40 min until the uranium extraction resin to be treated is fully expanded, and then filtering.

6. The method of claim 1, wherein the uranium extraction resin is regenerated by, The ratio of the diameter to the height of the resin bed layer is 1:2-1:

15.

7. The method of claim 6, wherein the uranium extraction resin is regenerated by, The height of the resin bed layer is 3-3.5 m, and the diameter is 1-1.2 m.

8. The method of claim 1, wherein the uranium extraction resin is regenerated by, In step 2, the uranium extraction resin to be treated is regenerated, and then the resin is washed.

9. The method of claim 8, wherein the uranium extraction resin is regenerated by, The step of washing the resin comprises washing the resin bed layer with water at a flow rate of 2-10 BV / h for 1-4 hours until the pH value of the effluent is neutral, and then taking out the resin and soaking it in deionized water for 1-2 hours.

10. The method of claim 1, wherein the uranium extraction resin is regenerated by, The uranium extraction resin is a strong alkaline anion exchange resin.

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