A process for the recovery of uranium from a crushed resin

Abstract

The application provides a method for recovering uranium in broken resin, and relates to the technical field of uranium ore in-situ leaching.The method for recovering uranium in broken resin provided by the application comprises the following steps: (1) performing water reduction treatment on the broken resin to obtain pretreated resin; (2) performing oxygen-rich carbonization on the pretreated resin to obtain sintered slag; (3) mixing the sintered slag and fine mud, and performing grinding to obtain solid mixed powder; (4) performing sulfuric acid stirring leaching on the solid mixed powder, adding lime to the obtained leaching system, adjusting the pH to 1.5-2, and obtaining a mixture; (5) performing filtration on the mixture to obtain supernatant; and (6) performing ion exchange on the supernatant to recover uranium.The application can realize recovery of uranium in broken resin, and effectively avoid resource loss.

Description

Technical Field

[0001] This invention relates to the field of uranium leaching technology, specifically to a method for recovering uranium from crushed resin. Background Technology

[0002] Moving bed ion exchange towers are commonly used equipment in the leaching solution treatment stage of uranium mining and metallurgy. The metal exchange carrier inside the tower is ion exchange resin. During operation, the resin in each tower exits in stages and is transported to the next tower through resin metering tanks (vessels) and air lift pipelines. During this process, due to friction and collision between the resin and the container walls, it is subjected to compression, abrasion, and breakage, which may cause it to penetrate the filter screen or float to the top of the rinsing tower and flow out, potentially resulting in metal loss.

[0003] When using a rinsing agent to wash uranium-loaded resin, metal residues may remain on the resin, and broken resin can cause excessive pressure and blockage in the ion exchange tower. Currently, there is no solution for dealing with this type of broken resin.

[0004] Sintering of organic matter may form coke residue, which can coat metals and affect dissolution and recovery; at the same time, the resulting carbon residue is relatively light and floats on the surface of the solution, which can also affect recovery. Summary of the Invention

[0005] The purpose of this invention is to provide a method for recovering uranium from crushed resin. This invention can realize the recovery of uranium from crushed resin and effectively avoid resource loss.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for recovering uranium from crushed resin, comprising the following steps:

[0008] (1) The crushed resin is subjected to water reduction treatment to obtain pretreated resin;

[0009] (2) The pretreated resin is subjected to oxygen-enriched carbonization to obtain sintered slag;

[0010] (3) The sintered slag and fine mud are mixed and ground to obtain a solid mixed powder;

[0011] (4) The solid mixed powder is subjected to sulfuric acid stirring leaching, and lime is added to the resulting leaching system to adjust the pH to 1.5-2, so as to obtain a mixture;

[0012] (5) Filter the mixture to obtain the supernatant;

[0013] (6) The supernatant is subjected to ion exchange to recover uranium.

[0014] Preferably, the water reduction treatment in step (1) includes vacuum filtration or coarse filtration and drying in sequence.

[0015] Preferably, the water content of the pretreated resin is less than 30%.

[0016] Preferably, the oxygen-enriched carbonization temperature in step (2) is 400-800℃, and the holding time is 40 min-4 h.

[0017] Preferably, the heating process from room temperature to the oxygen-enriched carbonization temperature includes: heating to 60°C for 1-2 minutes, and then heating to the oxygen-enriched carbonization temperature for 5-15 minutes.

[0018] Preferably, the mass ratio of sintering slag to fine mud in step (3) is 1:5 to 20.

[0019] Preferably, the concentration of the sulfuric acid solution used in the sulfuric acid stirring leaching in step (4) is 5-30 g / L.

[0020] Preferably, the sulfuric acid stirring leaching time in step (4) is 1 to 6 hours, and the temperature is room temperature to 60°C.

[0021] Preferably, the filtration in step (5) includes returning the mixture to step (1) for water reduction treatment.

[0022] Preferably, after the ion exchange in step (6), the process further includes evaporating the resulting tail liquid.

[0023] This invention provides a method for recovering uranium from crushed resin. The method involves pre-treating the crushed resin by reducing its water content. The pre-treated resin is then subjected to oxygen-enriched carbonization, converting most organic matter into carbon dioxide and water vapor, which are carried away to obtain sintered slag. This sintered slag is mixed with fine mud and ground to obtain a solid mixed powder. The mixing and grinding with fine mud increases the specific gravity of the solid mixed powder, preventing the carbon residue from floating on the solution surface and improving recovery efficiency. The solid mixed powder is then subjected to sulfuric acid stirring leaching. Lime is added to the resulting leaching system to adjust the pH to 1.5–2, precipitating and removing any other metal ions that may be present, resulting in a mixture. This mixture is then filtered to obtain a supernatant. Finally, the supernatant is subjected to ion exchange to recover uranium. Using this method to treat uranium-loaded crushed resin produced by a moving bed ion exchange process, the uranium recovery rate reaches 99%, which is beneficial for resource recovery and meets environmental protection requirements. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of the method for recovering uranium from crushed resin according to Embodiment 1 of the present invention. Detailed Implementation

[0025] This invention provides a method for recovering uranium from crushed resin, comprising the following steps:

[0026] (1) The crushed resin is subjected to water reduction treatment to obtain pretreated resin;

[0027] (2) The pretreated resin is subjected to oxygen-enriched carbonization to obtain sintered slag;

[0028] (3) The sintered slag and fine mud are mixed and ground to obtain a solid mixed powder;

[0029] (4) The solid mixed powder is subjected to sulfuric acid stirring leaching, and lime is added to the resulting leaching system to adjust the pH to 1.5-2, so as to obtain a mixture;

[0030] (5) Filter the mixture to obtain the supernatant;

[0031] (6) The supernatant is subjected to ion exchange to recover uranium.

[0032] This invention involves treating crushed resin with water to obtain pretreated resin. In a specific embodiment of this invention, the crushed resin is an ion exchange resin used in a moving bed ion exchange tower for uranium mining and metallurgy. Preferably, the components of the crushed resin include one or more of polyvinyl chloride, polypropylene, uranium, chlorine, and nitrates. In this invention, the uranium in the crushed resin is in the hexavalent state.

[0033] In this invention, the water reduction treatment preferably includes vacuum filtration or a combination of coarse filtration and drying. In this invention, the vacuum filtration is preferably belt filtration, more preferably belt negative pressure filtration. In this invention, the coarse filtration is preferably performed by loading crushed resin into a filter bag to coarsely filter pore water.

[0034] In this invention, the moisture content of the pretreated resin is preferably 30% or less.

[0035] After obtaining the pretreated resin, the present invention performs oxygen-enriched carbonization on the pretreated resin to obtain sintered slag. In the present invention, the oxygen-enriched carbonization is preferably carried out in a rotary kiln. During the oxygen-enriched carbonization process, oxygen oxidation is performed, and the oxygen flow rate is preferably sufficient to blow up the pretreated resin.

[0036] In this invention, the preferred temperature for oxygen-enriched carbonization is 400–800°C, and the preferred holding time is 40 min–4 h, more preferably 1–2 h. This invention effectively prevents coke formation by controlling the temperature and time of oxygen-enriched carbonization in conjunction with oxygen-enriched blowing.

[0037] In this invention, the heating process from room temperature to the oxygen-enriched carbonization temperature preferably includes: heating to 60°C for 1-2 minutes, and then heating to the oxygen-enriched carbonization temperature for 5-15 minutes. This heating process prevents excessively rapid heating from causing coking and agglomeration.

[0038] After obtaining the sintered slag, the present invention mixes the sintered slag with fine mud and grinds them to obtain a solid mixed powder. In the present invention, the preferred mass ratio of the sintered slag to the fine mud is 1:5 to 20. In the present invention, the preferred particle size of the solid particles in the fine mud is -100 mesh, and the preferred mass content of coarse sand (particle size greater than 0.5 mm) and medium-coarse sand (particle size 0.25 to 0.5 mm) is less than 30%.

[0039] In this invention, the grinding is preferably carried out in a ball mill. In this invention, the particle size of the solid mixed powder is preferably -200 mesh.

[0040] After obtaining the solid mixed powder, the present invention subjectes the solid mixed powder to sulfuric acid stirring leaching, adds lime to the resulting leaching system, and adjusts the pH to 1.5-2 to obtain a mixture. In the present invention, the concentration of the sulfuric acid solution used in the sulfuric acid stirring leaching is preferably 5-30 g / L, more preferably 10-20 g / L. In the present invention, the liquid-to-solid ratio of the sulfuric acid stirring leaching is preferably 1 mL: 1-1.2 g.

[0041] In this invention, the sulfuric acid stirring leaching time is preferably 1-6 hours, more preferably 2-4 hours; the sulfuric acid stirring leaching temperature is preferably room temperature to 60°C. During the sulfuric acid stirring leaching process, hexavalent uranium combines with sulfate to form uranyl disulfate or uranyl trisulfate.

[0042] The purpose of adding lime to the resulting leaching system in this invention is to precipitate and remove any other metal ions that may be present.

[0043] After obtaining the mixture, the present invention filters the mixture to obtain a supernatant. In the present invention, the filtration is preferably a belt filter, more preferably a belt negative pressure filter. In the present invention, the filtration preferably includes: returning the mixture to step (1) for water reduction treatment.

[0044] After obtaining the supernatant, the present invention performs ion exchange on the supernatant to recover uranium. In the present invention, the ion exchange preferably includes: passing the supernatant through an ion exchange column packed with 201X7 resin for adsorption and uranium recovery at a contact time of 4-10 minutes. In the present invention, the ion exchange preferably employs a fixed bed.

[0045] In this invention, after the ion exchange, the process preferably further includes evaporating the resulting tailings. This invention achieves zero waste liquid discharge. In this invention, the uranium concentration of the tailings is preferably below 0.3 mg / L.

[0046] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0047] Example 1

[0048] A uranium mine employs a moving bed ion exchange process, in which resin exits the tower in stages and is transported to the next tower via resin metering tanks (vessels) and air lift pipelines. During this process, the resin breaks down due to friction and collision with the container walls, causing it to be squeezed, worn, and float to the top of the rinsing tower before flowing out.

[0049] Methods for recovering uranium from crushed resin, such as Figure 1 As shown, the steps are as follows:

[0050] S1: The crushed resin is filtered by belt negative pressure to reduce the moisture content to 30% to obtain pretreated resin;

[0051] S2: Place the pretreated resin in a rotary kiln and oxidize it with oxygen. The airflow speed should be such that the pretreated resin is blown up. First, raise the temperature to 60°C in 1 minute, then raise the temperature to 400°C in 10 minutes. After the temperature reaches 400°C, calcine for 1 hour to obtain sintered slag.

[0052] S3: Mix -100 mesh fine mud into the sintered slag, with a mass ratio of sintered slag to fine mud of 1:5, and grind it to -200 mesh using a ball mill to obtain a solid mixed powder;

[0053] S4: Place the solid mixed powder in a stirring tank, add 20 g / L sulfuric acid solution at a liquid-to-solid volume-to-mass ratio of 1 mL: 1 g, and carry out sulfuric acid stirring leaching at room temperature for 2 hours;

[0054] S5: After stirring is complete, add lime to the resulting leaching system to adjust the pH to 2, and obtain a mixture;

[0055] S6: Return the mixture to step S1 for belt negative pressure filtration to remove the precipitate and obtain the supernatant;

[0056] S7: The supernatant is passed through an ion exchange column packed with 201X7 resin for adsorption and uranium recovery at a contact time of 10 min.

[0057] S8: The uranium concentration of the remaining tailings is reduced to 0.3 mg / L, and forced evaporation is performed to achieve zero waste liquid.

[0058] The amount of coke produced during the roasting process in step S2 is small, and the solids in the sulfuric acid stirring leaching process in step S4 have a high specific gravity, which meets the stirring requirements.

[0059] The uranium in the uranium-loaded fragmented resin produced by the recyclable resin moving bed ion exchange process has a recovery rate of 99%, which is beneficial for resource recycling and meets environmental protection requirements.

[0060] Example 2

[0061] In a certain mine, during hydrometallurgical adsorption, resin moves between ion exchange towers. During backflushing, broken resin and some small-particle resin leak from the top screen of the tower and accumulate in a temporary storage and recovery facility. After a period of accumulation, a sample was taken, and the uranium content in the resin was found to be 5 mg / mL of wet resin, requiring recovery. The following steps were taken for treatment:

[0062] S1: Shovel out the broken resin, put it into a filter bag to coarsely filter the pore water, and place it in an open space to dry in a sunny and windless weather to obtain a pretreated resin with a water content of 30%.

[0063] S2: The pretreated resin is placed in a rotary kiln and oxidized by blowing oxygen. The airflow speed is controlled to blow up the resin particles. The temperature is first raised to 60°C in 2 minutes, and then raised to 400°C in 15 minutes. After the temperature reaches 400°C, it is calcined for 2 hours to obtain sintered slag.

[0064] S3: Mix -100 mesh fine mud into the sintered slag, with a mass ratio of sintered slag to fine mud of 1:5. Grind the mixture to -200 mesh using a ball mill to obtain a solid mixed powder.

[0065] S4: Place the solid mixed powder in a stirring tank, add 30g / L sulfuric acid solution at a liquid-to-solid volume mass ratio of 1mL:1g, heat to 40℃ for sulfuric acid stirring and leaching, and stir for 2 hours;

[0066] S5: After stirring is complete, add lime to the resulting leaching system to adjust the pH to 2, and obtain a mixture;

[0067] S6: The mixture is subjected to belt negative pressure filtration to obtain supernatant, and the uranium concentration is determined to be 21 mg / L;

[0068] S7: The supernatant is passed through a fixed-bed resin column filled with 201X7 resin for adsorption and uranium recovery at a contact time of 10 min.

[0069] S8: The uranium concentration of the remaining tailings is reduced to 0.3 mg / L, and forced evaporation is performed to achieve zero waste liquid.

[0070] 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 for recovering uranium from crushed resin, comprising the steps of: (1) subjecting the crushed resin to water reduction treatment to obtain pretreated resin; (2) subjecting the pretreated resin to oxygen-enriched carbonization to obtain sintered slag; the oxygen-enriched carbonization in step (2) is performed at a temperature of 400-800℃ for 40 min-4 h; (3) mixing the sintered slag and fine mud, and grinding to obtain a solid mixed powder; the mass ratio of the sintered slag to the fine mud in step (3) is 1:5-20; (4) subjecting the solid mixed powder to sulfuric acid agitation leaching, adding lime to the obtained leaching system to adjust the pH to 1.5-2, and obtaining a mixture; the sulfuric acid agitation leaching in step (4) is performed using a sulfuric acid solution with a concentration of 5-30 g / L; (5) filtering the mixture to obtain supernatant; (6) subjecting the supernatant to ion exchange to recover uranium.

2. The recycling method according to claim 1, characterized in that, The water reduction treatment in step (1) comprises suction filtration or sequential coarse filtration and air drying.

3. The recycling method according to claim 1, characterized in that, The pretreated resin has a water content of 30% or less.

4. The recycling method of claim 1, wherein, The temperature rising procedure for rising from room temperature to the temperature of the oxygen-enriched carbonization comprises rising to 60℃ for 1-2 min, and then rising to the temperature of the oxygen-enriched carbonization for 5-15 min.

5. The recycling method of claim 1, wherein, The sulfuric acid agitation leaching in step (4) is performed for 1-6 h at a temperature of room temperature to 60℃.

6. The recycling method of claim 1, wherein, The filtering in step (5) comprises returning the mixture to step (1) for water reduction treatment.

7. The recycling method of claim 1, wherein, After the ion exchange in step (6), the obtained tail liquid is further evaporated.

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