A method of elution of a uranyl sulfate type resin

Abstract

The application provides a method for elution of uranyl sulfate type resin, and relates to the technical field of elution of uranium. The method adopts a two-step elution process, i.e., first, converting the uranyl sulfate loaded resin into uranyl carbonate loaded resin, and then directly eluting uranium from the uranyl carbonate loaded resin, so that the volume of the elution bed can be reduced, the peak uranium concentration in the elution liquid can be increased, the elution qualified liquid can be directly used for uranium precipitation, the process flow is simplified, and the cost is reduced. The results of the examples show that, by using the method, uranium can be directly eluted from the uranyl sulfate loaded resin with low adsorption capacity, the volume number of the elution bed is reduced to 3-4 BV, the peak uranium concentration in the elution liquid reaches 25-40 g / L, and the uranium can be directly precipitated.

Description

Technical Field

[0001] This invention relates to the field of uranium leaching technology, and more particularly to a leaching method using uranyl sulfate-type resin. Background Technology

[0002] In acid leaching uranium mining, anion exchange resins are typically used to adsorb uranium from the sulfuric acid leaching solution. As mining continues, the uranium concentration in the leaching solution decreases year by year, with some acid leaching mines showing uranium concentrations as low as a few tens of milligrams per liter. Furthermore, due to the continuous enrichment of chloride ions in uranium hydrometallurgical processes, some acid leaching mines have chloride ion concentrations as high as several tens of grams per liter, resulting in low saturated adsorption capacity of the ion exchange resins, with uranium adsorption capacities sometimes as low as 10 mg / mL. Simultaneously, the uranium concentration in the leaching solution decreases, making direct uranium precipitation impossible. Instead, a saturated re-adsorption process or extraction process must be used to re-enrich the uranium, increasing process time and production costs. Summary of the Invention

[0003] The purpose of this invention is to provide a rinsing method for uranyl sulfate-type resin, which can increase the peak uranium concentration in the rinsing solution, reduce the rinsing bed volume, and enable the qualified rinsing solution to directly precipitate uranium, thereby simplifying the process and reducing costs.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a rinsing method for uranyl sulfate-type resins, comprising the following steps:

[0006] Uranyl sulfate-supported resin was dynamically transformed using Na2CO3 solution to obtain uranyl carbonate-supported resin.

[0007] The uranyl carbonate-supported resin is eluted with an eluent; the eluent includes an eluent and a hydrolytic agent; the eluent is one of NaCl, NaNO3, and (NH4)2CO3; the hydrolytic agent is one of NaHCO3, Na2CO3, and NH4HCO3.

[0008] Preferably, the process before dynamic transformation further includes rinsing the uranyl sulfate-loaded resin with water.

[0009] Preferably, the rinsing is continued until the pH of the effluent is 7.

[0010] Preferably, the concentration of the Na2CO3 solution is 0.5–2.5 mol / L.

[0011] Preferably, the concentration of the eluent in the rinsing agent is 0.5–2.5 mol / L.

[0012] Preferably, the concentration of hydrolysate in the rinsing agent is 1-10 g / L.

[0013] Preferably, after rinsing, a qualified uranium rinsing solution and a lean rinsing solution are obtained. The lean rinsing solution is directly returned to the rinsing process, and the qualified uranium rinsing solution is directly used for uranium precipitation.

[0014] Preferably, the dynamic transformation process further includes: adding Na2CO3 to the transformed liquid and returning it to the dynamic transformation process for recycling.

[0015] Preferably, the contact time for rinsing is 30 to 90 minutes.

[0016] This invention provides a rinsing method for uranyl sulfate-type resin, comprising the following steps: dynamically transforming uranyl sulfate-supported resin with Na2CO3 solution to obtain uranyl carbonate-supported resin; rinsing the uranyl carbonate-supported resin with an rinsing agent; wherein the rinsing agent comprises an eluent and a hydrolytic agent; wherein the eluent is one of NaCl, NaNO3, and (NH4)2CO3; and wherein the hydrolytic agent is one of NaHCO3, Na2CO3, and NH4HCO3.

[0017] This invention employs a two-step elution process. First, uranyl sulfate-supported resin is converted to uranyl carbonate-supported resin. Then, uranium is directly eluted from the uranyl carbonate-supported resin. This reduces the elution bed volume, increases the peak uranium concentration in the eluent, and allows for direct uranium precipitation from the qualified eluent, simplifying the process and reducing costs. The results of the embodiments show that the method of this invention can directly elute uranium from uranyl sulfate-supported resin with low adsorption capacity, reducing the elution bed volume to 3–4 BV and achieving a peak uranium concentration of 25–40 g / L in the eluent, enabling direct uranium precipitation. Attached Figure Description

[0018] Figure 1 This is a flowchart of the rinsing method for the uranyl sulfate type resin of the present invention. Detailed Implementation

[0019] This invention provides a rinsing method for uranyl sulfate-type resins, comprising the following steps:

[0020] Uranyl sulfate-supported resin was dynamically transformed using Na2CO3 solution to obtain uranyl carbonate-supported resin.

[0021] The uranyl carbonate-supported resin is eluted with an eluent; the eluent includes an eluent and a hydrolytic agent; the eluent is one of NaCl, NaNO3, and (NH4)2CO3; the hydrolytic agent is one of NaHCO3, Na2CO3, and NH4HCO3.

[0022] In this invention, the uranyl sulfate-supported resin is preferably obtained by adsorbing uranium from a sulfuric acid leaching solution using an anion exchange resin. This invention does not have special requirements for the anion exchange resin; any anion exchange resin known in the art for adsorbing uranium is acceptable. The uranyl sulfate-supported resin is preferably a saturated adsorption resin.

[0023] Before the dynamic transformation, the present invention preferably rinses the uranyl sulfate-loaded resin with water.

[0024] The present invention does not have special requirements for the rinsing process, and rinsing is sufficient until the pH of the effluent is 7. Since the resin adsorbs uranium from the acidic leaching solution, the present invention uses water rinsing first to avoid the generation of a large number of bubbles in the bed during subsequent dynamic transformation.

[0025] After rinsing, the present invention uses Na2CO3 solution to dynamically transform the rinsed uranyl sulfate-supported resin to obtain uranyl carbonate-supported resin.

[0026] In this invention, the concentration of the Na₂CO₃ solution is preferably 0.5–2.5 mol / L, more preferably 1.0–2.0 mol / L. In this invention, the contact time for the dynamic transformation is preferably 30–90 min. After the dynamic transformation is completed, this invention preferably further includes: adding Na₂CO₃ to the dynamically transformed solution and returning it to the dynamic transformation process for recycling.

[0027] After obtaining the uranyl carbonate-supported resin, the present invention uses a rinsing agent to rinse the uranyl carbonate-supported resin to obtain a qualified uranium rinsing solution and a lean rinsing solution.

[0028] In this invention, the rinsing agent includes an eluent and a hydrolytic agent; the eluent is one of NaCl, NaNO3, and (NH4)2CO3; and the hydrolytic agent is one of NaHCO3, Na2CO3, and NH4HCO3.

[0029] In this invention, the concentration of the eluent in the rinsing agent is preferably 0.5–2.5 mol / L, more preferably 1–2 mol / L; the concentration of the hydrolytic agent in the rinsing agent is preferably 1–10 g / L, more preferably 3–8 g / L, and even more preferably 4–6 g / L. In this invention, the hydrolytic agent serves to prevent uranium hydrolysis.

[0030] In this invention, the contact time for rinsing is preferably 30–90 min, more preferably 40–80 min, and even more preferably 50–70 min; the flow rate of the rinsing agent is preferably 5.3–16 mL / h, more preferably 7.1–14.2 mL / h, and even more preferably 8.9–12.4 mL / h. Using the method of this invention, the amount of rinsing agent used can be reduced to 3–4 BV.

[0031] The present invention preferably involves directly precipitating uranium in the qualified uranium leaching solution and directly returning the lean leaching solution to the leaching process.

[0032] Figure 1 This is a flow chart of the rinsing method for the uranyl sulfate type resin of the present invention. Figure 1 As shown, the saturated uranyl sulfate resin is first converted using sodium carbonate solution to convert the uranyl sulfate on the resin into uranyl carbonate. Then, the uranyl carbonate-loaded resin is routinely leached using leaching agents such as sodium chloride. The resulting qualified uranium leaching solution is directly fed into the uranium precipitation process.

[0033] The following detailed description of the rinsing method for uranyl sulfate-type resin provided by the present invention, in conjunction with embodiments, should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1

[0035] A uranyl sulfate-supported resin, saturated with uranium, is used in an acidic leachate. The resin's saturated adsorption capacity for uranium is 15 mg / mL. The specific rinsing steps are as follows:

[0036] (1) Neutralization: First, the loaded resin is rinsed with water for 45 minutes (flow rate 8 mL / h), and the pH of the effluent is 7.

[0037] (2) Dynamic transformation: The transformation agent is 1.5 mol / L Na2CO3 solution, the contact time is 60 min (flow rate 10.6 mL / h), and uranyl carbonate loaded resin is obtained. After transformation, Na2CO3 is added to the solution and it is returned to the transformation process for recycling.

[0038] (3) Leaching: The leaching agent is 1.5 mol / L NaCl + 2 g / L NaHCO3, the contact time is 60 min (flow rate 10.6 mL / h), and qualified uranium leaching solution and lean leaching solution are obtained. The uranium concentration of qualified uranium leaching solution is 31 g / L, the leaching volume is 3 BV, the lean leaching solution is directly returned to the leaching process, and the qualified uranium leaching solution is directly used for uranium precipitation.

[0039] Example 2

[0040] A uranyl sulfate-supported resin, saturated with uranium, is used in an acidic leachate. The resin's saturated adsorption capacity for uranium is 17 mg / mL. The specific rinsing steps are as follows:

[0041] (1) Neutralization: First, the loaded resin is rinsed with water for 60 min (flow rate 10.6 mL / h), and the pH of the effluent is 7.

[0042] (2) Transformation: The transforming agent is 2 mol / L Na2CO3, the contact time is 70 min (flow rate 12.4 mL / h), and uranyl carbonate-supported resin is obtained. After transformation, Na2CO3 is added to the solution and it is returned to the transformation process for recycling.

[0043] (3) Leaching: The leaching agent used was 1 mol / L NaNO3 + 5 g / L Na2CO3, and the contact time was 70 min (flow rate 12.4 mL / h). A qualified uranium leaching solution and a lean leaching solution were obtained. The qualified uranium leaching solution had a uranium concentration of 38 g / L and a leaching volume of 3 BV. The lean leaching solution was directly returned to the leaching process, while the qualified uranium leaching solution was directly used for uranium precipitation.

[0044] Example 3

[0045] A uranyl sulfate-supported resin, saturated with uranium, is used in an acidic leachate. The resin's saturated adsorption capacity for uranium is 16 mg / mL. The specific rinsing steps are as follows:

[0046] (1) Neutralization: First, the loaded resin is rinsed with water for 50 minutes (flow rate 8.9 mL / h), and the pH of the effluent is 7.

[0047] (2) Transformation: The transforming agent is 1 mol / L Na2CO3, the contact time is 70 min (flow rate 12.4 mL / h), and uranyl carbonate-supported resin is obtained. After transformation, Na2CO3 is added to the solution and it is returned to the transformation process for recycling.

[0048] (3) Leaching: The leaching agent used was 1.2 mol / L (NH4)2CO3 + 10 g / L NH4HCO3, and the contact time was 50 min (flow rate 8.9 mL / h). A qualified uranium leaching solution and a lean leaching solution were obtained. The qualified uranium leaching solution had a uranium concentration of 36 g / L and a leaching volume of 3 BV. The lean leaching solution was directly returned to the leaching process, while the qualified uranium leaching solution was directly used for uranium precipitation.

[0049] Comparative Example 1 (Existing Saturated Re-adsorption Process)

[0050] A uranyl sulfate-supported resin, saturated with uranium, is used in an acidic leachate. The resin's saturated adsorption capacity for uranium is 9 mg / mL (1R). The specific rinsing steps are as follows:

[0051] (1) The above-mentioned loaded resin (1R) was directly leached with 1.5 mol / L NaCl + 2 g / L NaHCO3 as leaching agent for a contact time of 60 min (flow rate 10.6 mL / h) to obtain qualified uranium leaching solution and lean leaching solution, wherein the uranium concentration in the qualified uranium leaching solution was 9.4 g / L.

[0052] (2) Saturated re-adsorption: The qualified rinsing solution obtained in (1) was re-adsorbed using unrinsed uranyl sulfate-supported resin (1R) for a contact time of 80 min (flow rate 14.2 mL / h) and the saturated adsorption capacity of the resin was 52.16 mg / mL (2R).

[0053] (3) The saturated resin (2R) obtained in (2) was leached again using 1.5 mol / L NaCl + 2 g / L NaHCO3 as the leaching agent for a contact time of 60 min (flow rate 10.6 mL / h) to obtain a qualified uranium leaching solution and a lean leaching solution. The qualified leaching solution had a uranium concentration of 40 g / L and a leaching volume of 15 BV. The lean leaching solution was directly returned to the leaching process, and the qualified uranium leaching solution was directly used for uranium precipitation.

[0054] As can be seen from the above embodiments and comparative examples, the rinsing method of the present invention enables direct rinsing of uranyl sulfate-supported resin with low adsorption capacity, which can reduce the volume of the rinsing bed, increase the peak uranium concentration in the rinsing solution, and achieve the purpose of directly precipitating uranium from qualified rinsing solution.

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method of elution of a uranyl sulfate type resin, characterized in that, The method comprises the following steps: The uranyl sulfate loaded resin is dynamically transformed by using a Na2CO3 solution to obtain a uranyl carbonate loaded resin; The uranyl carbonate loaded resin is leached by using a leaching agent; the leaching agent comprises an eluent and an anti-hydrolysis agent; the eluent is one of NaCl, NaNO3 and (NH4)2CO3; the anti-hydrolysis agent is one of NaHCO3, Na2CO3 and NH4HCO3.

2. The elution method according to claim 1, characterized in that, Before the dynamic transformation, the uranyl sulfate loaded resin is flushed by using water.

3. The elution method according to claim 2, characterized in that, The pH value of the effluent of the flushing is 7.

4. The elution method of claim 1, wherein, The concentration of the Na2CO3 solution is 0.5-2.5 mol / L.

5. The elution method of claim 1, wherein, The concentration of the eluent in the leaching agent is 0.5-2.5 mol / L.

6. The elution method of claim 1, wherein, The concentration of the anti-hydrolysis agent in the leaching agent is 1-10 g / L.

7. The method of claim 1 wherein, After the leaching, a qualified uranium leaching liquid and a poor leaching liquid are obtained; the poor leaching liquid is directly returned to the leaching procedure; and the qualified uranium leaching liquid is directly subjected to uranium precipitation.

8. The elution method of claim 1, wherein, After the dynamic transformation, Na2CO3 is additionally added to the liquid after the dynamic transformation to return to the dynamic transformation procedure for cyclic use.

9. The method of claim 1 wherein, The contact time of the leaching is 30-90 min.

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