A method for extracting uranium from tantalum-niobium ore residues

Abstract

The application discloses a method for extracting uranium from tantalum-niobium ore leaching residue, which comprises the following steps: putting the ore leaching residue into lime milk for neutralization and precipitation pretreatment, controlling the neutralization and precipitation reaction conditions, removing the residual acid and fluorine in the liquid phase and recovering the uranium. The pretreated slurry is transferred to a thickener for sedimentation separation, and thickened ore slurry is obtained. Carbonate is added to the thickened ore slurry, and ozone is introduced, and the uranium is extracted by using the oxidation method and the alkali method. The uranium leaching solution is combined with washing water, and is prepared into an adsorption stock solution. The 201x7 strong alkaline anion exchange resin is used to separate and purify the uranium. The uranium is subjected to neutralization and precipitation, filtration and filter cake washing, and the obtained "yellow cake" is a qualified diuranate product. The application aims to improve the uranium recovery rate in the tantalum-niobium ore leaching residue, realize comprehensive recovery and utilization of the co-associated uranium resources in the tantalum-niobium ore, and realize energy saving and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of tantalum-niobium ore technology, and more particularly to a method for extracting uranium from tantalum-niobium ore extraction residue. Background Technology

[0002] Currently, tantalum-niobium ore typically contains associated radioactive nuclides such as uranium and thorium, classifying it as radioactive material. The uranium content in tantalum-niobium ore ranges from 0.2% to 0.5% by mass, with some reaching 20%. Industrially, a hydrometallurgical process using concentrated hydrofluoric acid and concentrated sulfuric acid is employed to extract tantalum and niobium from the ore. During the acid decomposition of tantalum-niobium ore, radioactive uranium produces insoluble fluorides. After slurry extraction, most of the uranium and other insoluble substances migrate to the extraction residue during the hydrometallurgical process, typically amounting to 15%-30% of the tantalum-niobium ore input. This extraction residue enriches the uranium content, with an enrichment factor of 2.56-6.19. The enrichment of uranium in the extraction residue, associated with the tantalum-niobium ore, results in excessive levels of radioactive material, necessitating management and comprehensive recycling as radioactive waste. Generally, temporary storage is used for disposal, and the extraction residue is not further processed. This has resulted in the failure to comprehensively recover and utilize uranium resources in tantalum-niobium mines, wasting strategic uranium resources. It also increases the management costs for tantalum-niobium enterprises in temporarily storing associated radioactive waste. Furthermore, if management is not standardized or adequate, it may cause radioactive pollution or pose hidden dangers, posing a significant threat to the environment. Therefore, there is an urgent need to propose a method for effectively extracting radioactive uranium from tantalum-niobium ore extraction residues. Summary of the Invention

[0003] The main objective of this invention is to provide a method for liquid extraction of uranium from tantalum-niobium ore extraction residue, aiming to solve the technical problem that existing tantalum-niobium ore extraction residues do not effectively extract uranium.

[0004] To achieve the above objectives, the present invention provides a method for extracting uranium from tantalum-niobium ore extraction residue, the method comprising the following steps:

[0005] Step 1: Add the tantalum-niobium ore extraction residue to the lime slurry and stir thoroughly until the mixed slurry reaches the preset pH value. Then, control the temperature of the mixed slurry to 50℃~65℃ and keep it heated and stirred for 0.5~1.5h.

[0006] Step 2: Sediment the mixed slurry processed in Step 1 to obtain supernatant and mineral slurry;

[0007] Step 3: Place the slurry obtained in Step 2 into a reaction vessel, add a carbonate solution to the reaction vessel, and introduce ozone. Stir continuously at 60℃~90℃ for 3h~6h. Finally, filter to obtain uranium-containing leachate and filter residue.

[0008] Step 4: Perform multi-stage countercurrent washing on the filter residue from Step 3 to obtain multi-stage washing water. Mix the multi-stage washing water with the uranium-containing leaching solution, and then add a preset amount of sulfuric acid solution to obtain the uranium-containing adsorption stock solution.

[0009] Step 5: Uranium in the uranium-containing adsorption solution is adsorbed using ion exchange resin, and the saturated resin after adsorption is leached to obtain uranium-containing eluent.

[0010] Step 6: Add sodium hydroxide to the uranium-containing eluent to perform precipitation and uranium recovery treatment.

[0011] Optionally, in step 1, the preset pH value is 6.5 ± 0.2.

[0012] Optionally, step 3 specifically includes placing the slurry obtained in step 2 into a reaction vessel, adding a carbonate solution to the reaction vessel and heating and stirring. When the temperature of the solution in the reaction vessel rises to 40°C, ozone is introduced and the temperature is raised to 60°C to 90°C and stirred continuously for 3 to 6 hours, while controlling the pH value to 9.5 to 10.5. Finally, the solution is filtered to obtain uranium-containing leaching solution and filter residue.

[0013] Optionally, in step 3, the liquid-to-solid ratio of the carbonate solution to the slurry is (1.2-1.5) L:1 kg, and the carbonate solution is a mixed solution of sodium carbonate and sodium bicarbonate, wherein the concentration ratio of sodium carbonate to sodium bicarbonate is (25 g / L to 60 g / L): (5 g / L to 25 g / L).

[0014] Optionally, in step 2, the solids content of the slurry is 45%-55%.

[0015] Optionally, in step 4, the solid-liquid ratio in the multi-stage countercurrent washing is (0.5-1.0):1, and the washing water temperature is 55℃~65℃.

[0016] Optionally, in step 5, the ion exchange resin is a 201×7 strongly basic anion exchange resin.

[0017] Optionally, in step 6, a neutralization reaction is carried out with 30% NaOH and uranium-containing leaching solution to obtain a precipitated slurry, which is then aged and separated by sedimentation. The sedimented underflow slurry is filtered through a chamber filter press to obtain a filter cake, which is then washed to remove mother liquor residue. After washing, the target sodium diuranate product is obtained.

[0018] Optionally, before step 1, a lime slurry with a mass fraction of 7%-10% may be prepared using lime.

[0019] Optionally, the supernatant obtained in step 2 can be used as part or all of the solvent required to prepare lime milk.

[0020] Beneficial effects:

[0021] (1) The mineral extraction residue is pretreated by neutralization and precipitation to remove residual acid and fluorine entrained in the liquid phase and recover uranium;

[0022] (2) By selecting ozone and carbonate for alkaline leaching to extract uranium, the uranium leaching rate can be effectively improved. The oxidation-reduction potential of ozone in alkaline solution is 1.24V, which makes the oxidation-reduction efficiency higher and can also effectively avoid introducing other impurities into the solution.

[0023] (3) Uranium diuranate products are prepared by separating and purifying uranium by ion exchange, neutralizing and precipitating uranium;

[0024] (4) The supernatant from sedimentation separation is used to prepare effective lime slurry, thereby achieving effective recycling;

[0025] (5) This process is simple and reasonable, the process technology is feasible and the method is reliable. It is easy to achieve large-scale production and realize the purpose of efficiently extracting and recovering uranium resources associated with tantalum and niobium ore. Attached Figure Description

[0026] Figure 1 This is a schematic flowchart of a method for extracting uranium from tantalum-niobium ore extraction residue according to the present invention. Detailed Implementation

[0027] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0028] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0029] Reference Figure 1 This is a schematic flowchart of the method for extracting uranium from tantalum-niobium ore extraction residue according to the present invention. The method includes:

[0030] Step 1, the pretreatment step, involves adding the tantalum-niobium ore extraction residue to lime slurry and stirring thoroughly until the mixed slurry reaches the preset pH value, which is controlled at 6.5 ± 0.2. Specifically, based on the residual sulfuric acid and hydrofluoric acid entrained in the liquid phase of the tantalum-niobium ore extraction residue, the amount and feeding rate of the extraction residue are controlled, and the final pH value of the neutralization precipitation is controlled at 6.5 ± 0.2 to allow the sulfuric acid and hydrofluoric acid to generate calcium fluoride and calcium sulfate, thereby removing the residual acid and defluorinating the liquid phase of the extraction residue. If the pH value of the neutralization precipitation drops to 8.5, a slow feeding method for the extraction residue can be used to ensure the reaction conditions required for the neutralization precipitation reaction, effectively reducing and removing sulfate and defluorinating in the slurry, and effectively reducing the amount of carbonate required for subsequent uranium leaching from the extraction residue slurry. After the neutralization reaction is complete, the temperature of the mixed slurry is further controlled to rise to 50℃~65℃ and kept at this temperature for 0.5~1.5h with stirring. The purpose is to completely convert the uranium entrained in the liquid phase of the mineral extraction residue into calcium diuranate and transfer it into the solid phase, so as to realize the recovery of uranium, that is, to recover uranium from the liquid phase entrained in the mineral extraction residue, which can improve the uranium recovery rate. At the same time, the precipitation of fluorine into calcium fluoride also plays a role in fixing fluorine, which is beneficial to the process control of subsequent ion exchange separation and extraction of uranium.

[0031] The main reaction equations are as follows:

[0032] H + +OH - =H2O

[0033] Ca 2+ +SO4 2- =CaSO4↓

[0034] Ca 2+ +2F - =CaF2↓

[0035] 2UO2SO4+3Ca(OH)2=CaU2O7↓+2CaSO4↓+3H2O

[0036] 2UO2F2+3Ca(OH)2=CaU2O7↓+2CaF2↓+3H2O.

[0037] Step 2, sedimentation separation: The mixed slurry treated in Step 1 is subjected to sedimentation separation to obtain supernatant and slurry. Specifically, the mixed slurry treated in Step 1 is transferred to a thickener for sedimentation separation. The thickened supernatant is returned for the preparation of lime slurry, and a thickened slurry is left. Generally, the solids content of the slurry is 45%-55%.

[0038] Step 3, alkaline leaching and filtration: The slurry obtained in step 2 is placed into a reaction vessel, and a carbonate solution is added to the reaction vessel. Ozone is then introduced and stirred continuously at 60℃~90℃ for 3h~6h. Finally, the mixture is filtered to obtain uranium-containing leaching solution and filter residue.

[0039] Specifically, the slurry obtained in step 2 is placed in a reaction vessel, and a carbonate solution is added and heated with stirring. When the solution temperature in the reaction vessel rises to 40°C, ozone is introduced and the temperature is raised to 60°C–90°C with continuous stirring for 3–6 hours, while controlling the pH value to 9.5–10.5. Finally, the mixture is filtered to obtain uranium-containing leaching solution and filter residue. The liquid-to-solid ratio of the added carbonate solution to the slurry is (1.2–1.5) L:1 kg, and the carbonate solution is a mixture of sodium carbonate and sodium bicarbonate; preferably, the concentration ratio of sodium carbonate to sodium bicarbonate is (25 g / L–60 g / L):(5 g / L–25 g / L). The reaction mechanism of this step is based on the fact that the uranium in the dense slurry is mainly in the form of uranium tetrafluoride and a small amount of diuranate. Uranium tetrafluoride needs to be oxidized to hexavalent uranium under the combined action of an oxidizing agent and an alkaline leaching agent. Then, the uranium is converted into a soluble sodium uranyl tricarbonate solution through alkaline leaching. This process converts the uranium in the solid phase into a soluble sodium uranyl tricarbonate solution, and uranium-containing leachate is obtained through solid-liquid separation. The main chemical reaction equations are as follows:

[0040] UF4+4Na2CO3+O3→Na4UO2(CO3)3+4NaF+CO2↑+O2↑

[0041] CaU2O7+Na2CO3+6NaHCO3=2Na4UO2(CO3)3+CaCO3↓+3H2O.

[0042] It is evident that the principle behind improving uranium leaching rate by selecting ozone and carbonates for alkaline leaching is that uranium tetrafluoride is poorly soluble in water, with a solubility product constant pKsp of 21.24 at room temperature. Although the solubility of uranium tetrafluoride in water is very low, it increases with increasing reaction temperature. Therefore, a higher reaction temperature is used to increase the uranium leaching rate, allowing uranium to be completely converted into a soluble sodium uranyl tricarbonate solution. Furthermore, the redox potential of ozone in alkaline solution is 1.24 V, resulting in higher redox efficiency and effectively preventing the introduction of other impurities into the solution. The leaching rate is calculated by detecting the uranium concentration in the leaching solution as C1 (g / L) and recording the leaching solution volume as V1 (ml); and by detecting the uranium concentration in the wash water to be combined with the leaching solution in step 4, calculating it to be C2 (g / L) and recording the leaching solution volume as V2 (ml). The sum of the product of the uranium concentration and its volume in the two solutions is divided by 1000, and then divided by the product of the dry basis mass m (g) of the tantalum-niobium ore extraction residue and the uranium mass percentage ω (%). The resulting value is multiplied by 100% to obtain the uranium leaching rate of the extraction residue. The calculation formula is as follows:

[0043]

[0044] In this embodiment, the uranium leaching rate is greater than 93%.

[0045] Step 4: Washing and preparation of the adsorption stock solution. The filter residue from Step 3 is subjected to multi-stage countercurrent washing to obtain multi-stage wash water. This multi-stage wash water is mixed with the uranium-containing leaching solution, and then a predetermined amount of sulfuric acid solution is added to obtain the uranium-containing adsorption stock solution. Specifically, the uranium concentration and pH value of the combined wash water and leaching solution need to be tested in advance. The adsorption stock solution is then acidified with sulfuric acid to prepare an adsorption stock solution that meets the conditions required for ion exchange. The uranium concentration of the adsorption stock solution is tested to be 0.6 g / L to 1.6 g / L, and the total acidity is pH 1.0 ± 0.2. Only after passing the tests can the next process be carried out. If the conditions are not met, the adsorption stock solution needs to be adjusted and prepared again.

[0046] Step 5: Ion exchange. Uranium in the uranium-containing adsorption solution is adsorbed using an ion exchange resin. The saturated resin after adsorption is then leached to obtain a uranium-containing eluent. Specifically, the ion exchange resin is a 201×7 strongly basic anion exchange resin. The process involves determining whether the uranium-containing eluent is a qualified uranium solution. Eluent that does not meet the qualified uranium solution standard is returned to Step 4 for sulfuric acid acidification and preparation of the adsorption solution. The criteria are: the uranium content U in the qualified uranium solution must be ≥10 g / L, and the uranium content U in the adsorption tail liquid must be <10 mg / L.

[0047] Step 6, uranium extraction: Sodium hydroxide is added to the uranium-containing eluent for precipitation and uranium recovery. Specifically, 30% NaOH is used to neutralize the uranium-containing eluent, with the reaction temperature controlled at 55℃~75℃, precipitation time at 4h-6h, and pH value at 6.5~7.5. A precipitate slurry is obtained, which is then aged and separated by sedimentation. The underflow slurry after sedimentation is filtered through a chamber filter press to obtain a filter cake. The filter cake is then washed to remove residual mother liquor, yielding the target sodium diuranate product. This ensures that the quality of the prepared sodium diuranate product meets the requirements of the "Technical Conditions for Diuranates" (EJ / T803-93).

[0048] Furthermore, prior to step 1, a lime slurry with a mass fraction of 7%-10% is prepared using lime. Specifically, industrial water or the supernatant returned from a thickener is added to a neutralization and precipitation reaction tank, stirring is started, and industrial-grade slaked lime is added to prepare a 7%-10% lime slurry. Then, the mineral extraction residue is added to the lime slurry, stirred thoroughly, and subjected to neutralization and precipitation pretreatment. The added mineral extraction residue is a wet residue with a U (dry basis) of 0.51%-3.10% and H₂O of 25%-40%. The liquid phase contains a certain amount of sulfuric acid and hydrofluoric acid, and the total acid content is ∑H₂O. + (液相夹 bring ) ≥12.00mol / L.

[0049] Furthermore, to better illustrate the above-mentioned reaction effects, the following specific examples and comparative examples are provided for further explanation, as detailed below:

[0050] Example 1

[0051] Tantalum-niobium ore extraction residue, U (干基) :0.68%, H2O:25.80%, ΣH + (液相夹带) 12.81 mol / L.

[0052] Step 1: Take a 1000ml PTFE beaker, add 550ml of industrial water or thickener supernatant to the beaker, turn on the stirrer, add industrial grade quicklime, stir for 0.5h to prepare a 7% lime slurry; add the mineral extraction residue (wet residue) to the lime slurry for neutralization and precipitation. While adding the mineral extraction residue, observe the pH value of the solution with a pH meter. When the pH value drops to 8.5, slowly add the mineral extraction residue. The final pH value of the neutralization and precipitation is 6.6. Record the amount of mineral extraction residue (wet residue) added (g).

[0053] Then, turn on the water bath to heat up the temperature, continue stirring the liquid that has been adjusted to the final pH value, and control the uranium precipitation reaction temperature at 50°C and the time at 1 hour; stop heating and stirring, and allow it to cool down naturally.

[0054] Step 2: Transfer the pretreated slurry to a thickener for sedimentation separation to obtain a thickened slurry. The supernatant is returned for preparation of lime slurry. The supernatant is sent for analysis to determine U: 0.6 mg / L, F... - 14 mg / L.

[0055] Step 3: Add the concentrated slurry to a 1000ml beaker, start stirring and heat, add a mixed solution of 43g / L Na₂CO₃ + 15g / L NaHCO₃, and maintain the liquid-to-solid ratio of carbonate solution to slurry at 1.2L:1kg. When the solution temperature reaches 40℃, introduce ozone and extract uranium using oxidation and alkaline leaching methods. Continue heating to maintain the leaching reaction temperature at 85℃±2℃ for 4.5 hours, controlling the remaining Na₂CO₃ and NaHCO₃ amounts. The final pH value of the leaching endpoint is measured to be 10.4. Filter after natural cooling to 60℃, and measure and record the volume (ml) of the leachate at room temperature.

[0056] Step 4: Add an appropriate amount of washing water (61℃ industrial water) to a 1000ml beaker, start stirring, and gradually add the filter cake to the beaker washing water for pulping and washing. The liquid-to-solid ratio is 0.65:1. After three countercurrent washings, the washing water from the third wash is combined with the leachate, and then acidified with sulfuric acid to adjust the pH to 1.0. Stirring continues for 0.5 hours to prepare the uranium adsorption stock solution. Measure and record the volume (ml) of the adsorption stock solution, the wet weight (g) and dry weight (g) of the washed filter cake, and the moisture content (%). The adsorption stock solution was sent for analysis and testing. U: 1.172 g / L; the percentage of uranium content after drying the filter cake to constant weight was U (dry basis): 0.036%. Calculations show that the uranium leaching rate E (based on slag) is 93.62% and the uranium leaching rate E (based on liquid) is 93.48%.

[0057] Step 5: The uranium in the above adsorption solution is purified and separated using a 201×7 strong basic anion exchange resin. The uranium-containing eluent is obtained by rinsing and is considered a qualified uranium solution. The volume (ml) of the qualified uranium solution is measured and recorded, and the uranium concentration (U) is 18.56 g / L.

[0058] Step 6: Using 30% NaOH as a precipitant, the precipitation temperature was 65℃, the precipitation time was 4.5h, and the pH was 7.2. The precipitated slurry underwent multiple batch aging treatments. The underflow slurry after sedimentation and separation was vacuum filtered through a Buchner funnel. A single pulping and washing process followed by two pan washings (washing liquid-to-solid ratio of 0.6 / 1) was used to remove residual mother liquor entrained in the filter cake, resulting in a "yellow cake". Sodium diuranate product (on a dry basis): U: 56.12%, SO42- 2- 0.82%, PO4 3- 0.09%, SiO2: 0.25%, F - 0.09%, Cl - 0.06%.

[0059] Example 2

[0060] Tantalum-niobium ore extraction residue, U( 干基 ):1.16%, H2O:30.12%, ∑H + (液相夹带) 13.10 mol / L.

[0061] Step 1: Take a 1000ml PTFE beaker, add 550ml of industrial water or thickener supernatant to the beaker, turn on the stirrer, add industrial grade quicklime, stir for 0.5h to prepare a 7%-10% lime slurry; add the mineral extraction residue (wet residue) to the lime slurry for neutralization and precipitation. While adding the mineral extraction residue, observe the pH value of the solution with a pH meter. When the pH value drops to 8.5, slowly add the mineral extraction residue. The final pH value of the neutralization and precipitation is 6.7. Record the amount of mineral extraction residue (wet residue) added (g).

[0062] Turn on the water bath to heat up the temperature, continue stirring the liquid that has been adjusted to the final pH value, and control the uranium precipitation reaction temperature at 65℃ and the time at 0.5h; stop heating and stirring, and allow it to cool down naturally.

[0063] Step 2: Transfer the pretreated slurry to a thickener for sedimentation separation to obtain a thickened slurry. The supernatant is returned for preparation of lime slurry. The supernatant is sent for analysis to determine U: 0.6 mg / L, F... - 12mg / L.

[0064] Step 3: Add the concentrated slurry to a 1000ml beaker, start stirring and heat, add an appropriate amount of 50g / L Na₂CO₃ + 20g / L NaHCO₃ solution, and make the liquid-solid ratio of carbonate solution to slurry 1.3L:1kg. When the solution temperature rises to 40℃, ozone is introduced. Uranium is extracted by leaching using oxidation and alkaline methods. Continue to raise the temperature to maintain the leaching reaction temperature at 60℃±2℃, and react for 6.0h. Control the amount of residual Na₂CO₃ and NaHCO₃, and measure the pH value at the leaching endpoint to be 10.2. Filter when naturally cooled to 60℃, and measure and record the volume (ml) of the leaching solution at room temperature.

[0065] Step 4: Add an appropriate amount of washing water (62℃ industrial water) to a 1000ml beaker, start stirring, and gradually add the filter cake to the beaker washing water for pulping and washing. The liquid-to-solid ratio is 0.70:1. After three countercurrent washings, the washing water from the third wash is combined with the leachate, and then acidified with sulfuric acid to adjust the pH to 1.2. Stirring continues for 0.5 hours to prepare the uranium adsorption stock solution. Measure and record the volume (ml) of the adsorption stock solution, the wet weight (g) and dry weight (g) of the washed filter cake, and the moisture content (%). The adsorption stock solution is sent for analysis and testing; U: 1.460 g / L; the percentage of uranium content after drying the filter cake to constant weight is U (dry basis): 0.051%. Calculations show that the uranium leaching rate (E(based on slag)) is 95.41% and the uranium leaching rate (E(based on liquid)) is 95.18%.

[0066] Step 5: The uranium in the above adsorption solution is purified and separated using a 201×7 strong basic anion exchange resin. The uranium-containing eluent is obtained by rinsing and is considered a qualified uranium solution. The volume (ml) of the qualified uranium solution is measured and recorded, and the uranium concentration (U) is 19.20 g / L.

[0067] Step 6: Using 30% NaOH as a precipitant, the precipitation temperature was 65℃, the precipitation time was 4.5h, and the pH was 7.2. The precipitated slurry underwent multiple batch aging treatments. The underflow slurry after sedimentation and separation was vacuum filtered through a Buchner funnel. One pulping and washing process followed by two pan washings (the washing liquid-to-solid ratio was 0.6 / 1) was used to remove residual mother liquor entrained in the filter cake, resulting in a "yellow cake". Sodium diuranate product (on a dry basis): U: 58.62%, SO42- 2- 0.98%, PO4 3- 0.11%, SiO2: 0.36%, F - 0.08%, Cl - 0.05%.

[0068] Example 3

[0069] Tantalum-niobium ore extraction residue, U( 干基 ):0.89%, H2O:30.12%, ∑H + (液相夹带) 13.10 mol / L.

[0070] Step 1: Take a 1000ml PTFE beaker, add 550ml of industrial water or thickener supernatant to the beaker, turn on the stirrer, add industrial grade quicklime, stir for 0.5h, and prepare a 7%-10% lime slurry; add the mineral extraction residue (wet residue) to the lime slurry for neutralization and precipitation. While adding the mineral extraction residue, observe the pH value of the solution with a pH meter. When the pH value drops to 8.5, slowly add the mineral extraction residue. The final pH value of the neutralization and precipitation is 6.4. Record the amount of mineral extraction residue (wet residue) added (g).

[0071] Turn on the water bath to heat up, continue stirring the liquid that has been adjusted to the final pH value, and control the uranium precipitation reaction temperature at 60℃ and the time at 1 hour; stop heating and stirring, and allow it to cool down naturally.

[0072] Step 2: Transfer the pretreated slurry to a thickener for sedimentation separation to obtain a thickened slurry. The supernatant is returned for preparation of lime slurry. The supernatant is sent for analysis to determine U: 0.6 mg / L, F... - 11 mg / L.

[0073] Step 3: Add the concentrated slurry to a 1000ml beaker, start stirring and heating, add an appropriate amount of 38g / L Na₂CO₃ + 19g / L NaHCO₃ solution, and maintain the liquid-to-solid ratio of carbonate solution to slurry at 1.5L:1kg. When the solution temperature reaches 40℃, introduce ozone and extract uranium using oxidation and alkaline leaching methods. Continue heating to maintain the leaching reaction temperature at 85℃±2℃ for 4.5 hours, controlling the remaining Na₂CO₃ and NaHCO₃ amounts. Measure the pH at the leaching endpoint, which should be 10.1. Filter after natural cooling to 60℃, and measure and record the volume (ml) of the leachate at room temperature.

[0074] Step 4: Add an appropriate amount of washing water (industrial water at 65℃) to a 1000ml beaker, start stirring, and gradually add the filter cake to the beaker washing water for pulping and washing. The liquid-to-solid ratio is 0.85:1. After three countercurrent washings, the washing water from the third wash is combined with the leachate, and then acidified with sulfuric acid to adjust the pH to 1.0. Stirring continues for 0.5 hours to prepare the uranium adsorption stock solution. Measure and record the volume (ml) of the adsorption stock solution, the wet weight (g) and dry weight (g) of the washed filter cake, and the moisture content (%). The adsorption stock solution is sent for analysis and testing; U: 1.02 g / L. The percentage of uranium content after drying the filter cake to constant weight is U (dry basis): 0.05%. Calculations show that the uranium leaching rate E (based on slag) is 94.78% and the uranium leaching rate E (based on liquid) is 94.62%.

[0075] Step 5: The uranium in the above adsorption solution is purified and separated using a 201×7 strong basic anion exchange resin. The uranium-containing eluent is obtained by rinsing and is considered a qualified uranium solution. The volume (ml) of the qualified uranium solution is measured and recorded, and the uranium concentration (U) is 16.64 g / L.

[0076] Step 6: Using 30% NaOH as a precipitant, the precipitation temperature was 65℃, the precipitation time was 4.5h, and the pH was 7.2. The precipitated slurry underwent multiple batch aging treatments. The underflow slurry after sedimentation and separation was vacuum filtered through a Buchner funnel. One pulping and washing process followed by two pan washings (the washing liquid-to-solid ratio was 0.6:1) was used to remove residual mother liquor entrained in the filter cake, resulting in a "yellow cake". Sodium diuranate product (on a dry basis): U: 53.67%, SO42- 2- 0.75%, PO4 3- 0.08%, SiO2: 0.45%, F - 0.08%, Cl - 0.05%.

[0077] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0078] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0079] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for extracting uranium from tantalum-niobium ore processing residues, characterized in that, The method comprises the following steps: Step 1, the tantalum niobium ore leaching residue is added into lime milk, and the mixed slurry is stirred until the preset pH value is reached, and then the mixed slurry is heated to 50-65 DEG C, and heated and stirred for 0.5-1.5 h; Step 2, the mixed slurry treated in step 1 is subjected to sedimentation separation to obtain supernatant and ore slurry; Step 3, the ore slurry obtained in step 2 is placed in a reaction container, and a carbonate solution is added into the reaction container and ozone is introduced for continuous stirring at 60-90 DEG C for 3-6 h, and finally filtered to obtain a uranium-containing leaching solution and a filter residue; Step 4, the filter residue in step 3 is subjected to multi-stage countercurrent washing to obtain multi-stage washing water, and the multi-stage washing water is mixed with the uranium-containing leaching solution, and then a preset amount of sulfuric acid solution is added to obtain a uranium-containing adsorption stock solution; Step 5, ion exchange resin is used to adsorb uranium in the uranium-containing adsorption stock solution, and the saturated resin after adsorption is eluted to obtain a uranium-containing elution solution; Step 6, sodium hydroxide is added to the uranium-containing elution solution for precipitation and recovery of uranium.

2. The method of claim 1, wherein the method further comprises, In the step 1, the preset pH value is 6.5±0.

2.

3. The method of extracting uranium from a tantalum-niobium ore processing residue according to claim 1 or 2, characterized in that, In the step 3, the ore slurry obtained in step 2 is placed in a reaction container, and a carbonate solution is added into the reaction container and heated and stirred, when the solution temperature in the reaction container is increased to 40 DEG C, ozone is introduced and the temperature is increased to 60-90 DEG C for continuous stirring for 3-6 h, and the pH value is controlled to 9.5-10.5, and finally filtered to obtain a uranium-containing leaching solution and a filter residue.

4. The method of claim 3, wherein the method further comprises, In the step 3, the liquid-solid ratio of the carbonate solution to the ore slurry is (1.2-1.5) L:1 kg, the carbonate solution is a mixed solution of sodium carbonate and sodium bicarbonate, and the concentration ratio of sodium carbonate to sodium bicarbonate is (25-60 g / L):(5-25 g / L).

5. The method of claim 3, wherein the method further comprises, In the step 2, the solid content of the ore slurry is 45%-55%.

6. The method of extracting uranium from a tantalum-niobium ore processing residue as claimed in claim 3, characterized in that, In the step 4, the solid-liquid ratio in the multi-stage countercurrent washing is (0.5-1.0):1, and the washing water temperature is 55-65 DEG C.

7. The method of claim 3, wherein the method further comprises, In the step 5, the ion exchange resin is 201x7 strong alkaline anion exchange resin.

8. The method of claim 3, wherein the method further comprises, In the step 6, a neutralization reaction is carried out between 30% NaOH and the uranium-containing elution solution to obtain a precipitation slurry, which is aged and subjected to sedimentation separation, and the sedimentation underflow slurry is filtered by a box filter to obtain a filter cake, which is washed to remove residual mother liquor, and the target sodium diuranate product is obtained after washing.

9. The method of extracting uranium from a tantalum niobium ore processing residue according to any one of claims 4 to 8, characterised in that, Before the step 1, a lime milk with a mass fraction of 7%-10% is prepared by using lime.

10. The method of claim 9, wherein the method further comprises the step of: The supernatant obtained in the step 2 is used for part or all of the solvent required for preparing lime milk. ​

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