Method for comprehensively recovering tin and uranium from ore extraction residues of tantalum-niobium ore

Abstract

The invention discloses a method for comprehensively recovering tin and uranium from ore extraction residues of tantalum-niobium ore, and relates to the technical field of recovery treatment of ore extraction residues of tantalum-niobium ore. Comprising the following steps: pretreating ore extraction residues, filtering slurry and washing a filter cake to obtain filtrate, washing water and a washed filter cake; mixing the filtrate with washing water, performing causticization treatment, filtering to obtain precipitation mother liquor, and concentrating and returning the precipitation mother liquor for pretreatment to replace sodium hydroxide; the washed filter cake is subjected to a reselection method to obtain tin concentrate and tailing slag, and tin is recycled from the tin concentrate; uranium in the tailing slag is leached and extracted through an oxidation method and an alkaline method, uranium-containing alkaline leaching liquid is obtained through filtering, and uranium-containing crude products are obtained through neutralization and precipitation; decomposing the uranium-containing crude product through an acid method to extract uranium, filtering feed liquid to obtain uranium-containing acid decomposition liquid, and adjusting to prepare an adsorption stock solution; uranium is separated and purified through an ion exchange method, uranium qualified liquid is obtained through leaching, and a sodium diuranate product is obtained through neutralization precipitation, filtering and filter cake washing. According to the method, tin and uranium can be recycled from the tantalum-niobium ore extraction residues, and comprehensive recycling of tantalum-niobium ore resources is achieved.

Description

Technical Field

[0001] This invention relates to the field of tantalum-niobium ore extraction residue recovery and treatment technology, specifically to a method for the comprehensive recovery of tin and uranium from tantalum-niobium ore extraction residue. Background Technology

[0002] Tantalum-niobium concentrates are typically associated with tin and uranium. The mass percentage of uranium in tantalum-niobium ore is 0.2%–0.5%, while the mass percentage of tin is generally greater than 1%, and in some cases as high as 30%. Tantalum-niobium enterprises usually use a hydrometallurgical process involving concentrated hydrofluoric acid and concentrated sulfuric acid to extract tantalum-niobium from ore. During the smelting process, the extraction residue can be enriched with tin and uranium, which are associated with the tantalum-niobium ore and have high economic value. However, the enriched tin and uranium are radioactive materials, and improper management could lead to radioactive pollution or other hazards, causing significant environmental damage. Therefore, the comprehensive recovery of tin and uranium from the extraction residue is of significant environmental and economic importance.

[0003] The common practice among existing tantalum and niobium enterprises is to use lime slurry to neutralize and precipitate the extraction residue, without recovering valuable resources such as tin and uranium from the residue. Furthermore, the resulting neutralization slag is radioactive waste. Some tantalum and niobium enterprises use water washing to remove some acids and soluble salts from the extraction residue, followed by shaking table gravity separation to enrich tin, obtaining tin-containing minerals and selling them as tin concentrate. The resulting tailings have high radioactivity levels, and their temporary storage poses significant safety and environmental risks.

[0004] Because tantalum-niobium ore decomposes under high concentrations of hydrofluoric acid, the resulting extraction residue contains uranium tetrafluoride (UF4) and also contains some hydrated uranium fluoride crystals (UO2F2·nH2O), which are soluble substances. Currently, tantalum-niobium enterprises generally use water washing to process the extraction residue, which is dissolved during the washing process. After neutralization and precipitation with lime slurry, the concentration of radioactive nuclides in the neutralized precipitate is 2Bq / g to 5Bq / g. Since existing tantalum-niobium enterprises do not have the corresponding smelting and processing technology for radioactive mineral resources, the radioactivity in the neutralized precipitate is seriously exceeded, resulting in secondary pollution.

[0005] Chinese patent application CN117551894A discloses a method for improving the uranium leaching rate from tantalum-niobium ore extraction residue. This method involves pre-treating the extraction residue with neutralization and precipitation to remove residual acid and fluorine entrained in the liquid phase and recover uranium. Uranium is then extracted by alkaline leaching using ozone and carbonates to further improve the uranium leaching rate. However, this method only recovers uranium from the extraction residue and cannot achieve comprehensive recovery and utilization of tin and uranium from the residue. Therefore, there is an urgent need to develop a method for the comprehensive recovery of tin and uranium from tantalum-niobium ore extraction residue. Summary of the Invention

[0006] The technical problem this invention aims to solve is to provide a method for the comprehensive recovery of tin and uranium from the extraction residue of tantalum-niobium ore. Its purpose is to address the resource waste and radioactive environmental pollution caused by the ineffective extraction and recovery of tin and uranium resources from the extraction residue of existing tantalum-niobium ore.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for the comprehensive recovery of tin and uranium from the extraction residue of tantalum-niobium ore, the method comprising the following steps:

[0009] S1. Add the tantalum-niobium ore extraction residue to a sodium hydroxide solution, stir and heat for pretreatment, control the pretreatment reaction temperature at 40℃~65℃, the time at 3.0h~4.0h, and the final pH value at 13~14, then filter to separate the filter cake and filtrate, and wash the filter cake to obtain wash water.

[0010] S2. Mix the washing water and filtrate from S1, and perform causticization treatment with calcium hydroxide. Control the causticization reaction temperature at 92℃~105℃ and the time at 2.0h~3.0h. After the reaction is completed, filter the slurry to obtain a filtrate containing sodium hydroxide, which is then evaporated and concentrated and returned to be used for pretreatment to replace the sodium hydroxide solution.

[0011] S3. The washed filter cake from S1 is pulped and enriched by gravity separation on a shaking table to obtain tin concentrate and recover tin; the tailings obtained from gravity separation are used for uranium extraction and recovery.

[0012] S4. Uranium is extracted from the tailings slag in S3 by oxidation and alkaline leaching. The leaching solution is filtered to obtain uranium-containing alkaline leaching solution. The filter cake is washed to obtain wash water. The alkaline leaching solution and wash water are combined and subjected to sodium hydroxide alkali precipitation, filtration and filter cake washing to obtain uranium-containing crude product.

[0013] S5. Uranium-containing crude product from S4 is extracted using acid decomposition. The solution is filtered to obtain acid decomposition liquid, and the filter cake is washed to obtain wash water. The acid decomposition liquid and wash water are combined and adjusted to prepare the adsorption stock solution.

[0014] S6. The adsorbent solution in S5 is separated and purified by ion exchange. The uranium-containing qualified solution is obtained by rinsing. The uranium is recovered by neutralization and precipitation. After filtration, the filter cake is washed to obtain sodium diuranate product and the uranium is recovered.

[0015] Furthermore, in S1, sodium hydroxide is used as a pretreatment agent to pretreat uranium in the mineral extraction residue by transformation or conversion, preferably using a NaOH solution with a mass percentage concentration of ≥30%.

[0016] Furthermore, in S1, the pretreated slurry is filtered and separated by a chamber filter press to obtain filtrate and filter cake. The filter cake pulping is then subjected to two-stage cross-flow washing to obtain wash water, which is tap water.

[0017] Furthermore, in S2, the filtrate and wash water are mixed in a reaction vessel, stirring is started and heating is carried out, and industrial calcium hydroxide powder is gradually added. The industrial calcium hydroxide powder is selected from -320 mesh sieve material, and its mass percentage is ≥85.0%. Sodium carbonate is replaced with sodium hydroxide through causticization treatment. The slurry is filtered to obtain a filtrate containing sodium hydroxide, which is evaporated and concentrated to a sodium hydroxide mass percentage of ≥30%, and returned to S1 to prepare the sodium hydroxide solution required for pretreatment.

[0018] Furthermore, the S3 process is as follows: the filter cake after washing S1 is mixed with water to make a slurry, and the mass percentage of the slurry is controlled at 15%~25%; the slurry is subjected to gravity separation through a shaking table, the gravity-enriched heavy minerals are collected, and the main tin-containing minerals are obtained after dehydration, and tin is recovered, with a tin mass percentage of Sn≥40%, which can be sold as tin concentrate; the light minerals collected on the shaking table are separated into solid and liquid to obtain tailings slag.

[0019] Furthermore, the reaction process of S4 is as follows: the tailings slag is put into a reaction vessel containing the alkaline leaching agent, stirring is started and heating is carried out, an oxidant is added, the temperature is continued to rise, the reaction temperature is controlled at 95℃±5℃, the time is 12h~14h, the final pH value is 9.5~10.5, and the liquid is filtered to obtain uranium-containing alkaline leaching solution and filter cake.

[0020] Furthermore, in S4, the alkaline leaching agent is a sodium carbonate (Na2CO3) solution with a mass percentage of 10%~20% and a sodium bicarbonate (NaHCO3) solution with a mass percentage of 5%~10%, and the liquid-solid ratio of the alkaline leaching agent to the tailings slag is (1.5~3.0) L:1kg.

[0021] Furthermore, in S4, the oxidant is a sodium hypochlorite solution with an effective chlorine content (Cl) of ≥10%, and the liquid-to-solid ratio of the oxidant to the tailings slag is (0.025~0.100) L:1kg.

[0022] Furthermore, in S4, the over-alkali precipitation process is as follows: The mixture obtained by combining the alkaline leaching solution and the washing water is placed in a reaction vessel, stirring is started and heating is carried out. Sodium hydroxide solution is used as a precipitant for over-alkali precipitation to recover uranium. The mass percentage of sodium hydroxide solution is ≥30%. The over-alkali precipitation reaction temperature is controlled at 50℃±5℃, the time is 1.0h~1.5h, and the final pH value is 13~14. After that, the solution is filtered, and the filter cake after washing is the crude product containing uranium. The precipitate mother liquor obtained by filtration is concentrated by evaporation and used as a precipitant for the over-alkali precipitation of the next batch of alkaline leaching solution.

[0023] Furthermore, in S5, uranium-containing crude product is extracted by acid decomposition with dilute hydrochloric acid. The acid decomposition agent is a 15%~25% HCl solution by mass, and the liquid-to-solid ratio of dilute hydrochloric acid to filter cake is (2.0~4.0) L:1kg. The acid decomposition temperature is controlled at 40℃~60℃ and the time is 0.5h~1.5h. The uranium-containing acid decomposition solution obtained by filtration is combined with the wash water, and the pH value, uranium and chloride ion concentrations of the solution are adjusted to prepare the adsorption stock solution. The preset concentration of U (uranium) in the adsorption stock solution is 0.5~2.0g / L, and the H+ concentration is 0.5~2.0g / L. + >0.1mol / L, Cl - >4.5mol / L.

[0024] Furthermore, in S6, uranium is separated and extracted using a 201×7 strong basic anion exchange resin to obtain uranium-containing saturated resin and adsorption tail liquid; the saturated resin is eluted to obtain a qualified uranium-containing liquid, in which the uranium content U≥20g / L is obtained and the uranium content U≤20mg / L is obtained in the adsorption tail liquid.

[0025] Furthermore, in S6, the qualified uranium-containing liquid is neutralized and precipitated using industrial-grade sodium hydroxide solution to recover uranium. The mass percentage of the NaOH solution is ≥30%. The precipitated slurry is then aged and separated by sedimentation. The sedimented underflow slurry is filtered through a chamber filter press to obtain a filter cake. The filter cake is washed to remove mother liquor residue, and the target sodium diuranate product is obtained.

[0026] The present invention has the following beneficial effects:

[0027] Typically, the mass percentage of uranium in the extraction residue produced during the hydrometallurgical production process of tantalum and niobium enterprises is greater than 0.2%. This invention utilizes a pre-treated, washed filter cake that is then pulped and subjected to shaking table gravity separation to separate tin and uranium, yielding a tin concentrate enriched with tin minerals and uranium-containing tailings. Tin is then recovered from the tin concentrate, achieving comprehensive recovery of valuable tin resources from the extraction residue. Uranium is subsequently extracted through oxidation and alkaline leaching, followed by alkaline precipitation, filtration, and filter cake washing to obtain a crude uranium-containing product. Uranium is purified through acid decomposition and filtration separation, adsorption solution preparation, and ion exchange separation. The qualified uranium-containing solution is then neutralized and precipitated to recover uranium, aged, and subjected to solid-liquid separation to obtain a filter cake. After washing the filter cake to remove residual mother liquor, sodium diuranate is obtained. Thus, comprehensive recovery and utilization of tin and uranium resources from associated tantalum and niobium ores is achieved.

[0028] Compared with existing technologies, it has the following advantages:

[0029] (1) This invention utilizes the characteristics of the minerals themselves, employing sodium hydroxide to neutralize and precipitate the mineral extraction residue as a pretreatment. This process converts the hydrated uranyl fluoride (UO2F2·nH2O) crystals in the solid phase of the mineral extraction residue into water-insoluble sodium diuranate, which is then reintroduced into the solid phase. Simultaneously, it transforms the uranyl sulfate (UO2SO4) and uranyl fluoride (UO2F2) entrained in the liquid phase into water-insoluble sodium diuranate precipitate (solid), thus converting the uranium compounds in the liquid phase into the solid phase. This pretreatment enables the recovery of uranium from both the solid and liquid phases of the mineral extraction residue. Furthermore, the sodium hydroxide pretreatment of the sulfuric acid and hydrofluoric acid entrained in the liquid phase, followed by solid-liquid separation and filter cake washing, removes fluoride and sulfate ions from the residue, facilitating subsequent ion exchange separation and purification of uranium.

[0030] (2) The mixture obtained from the pretreatment is causticized to obtain sodium hydroxide by displacement. The slurry is filtered and then evaporated and concentrated. After solid-liquid separation, a filtrate containing sodium hydroxide is obtained. The filtrate is evaporated and concentrated until the mass percentage of sodium hydroxide is ≥30%. It is then returned to the pretreatment to replace the required sodium hydroxide solution, thus reducing the amount of sodium hydroxide reagent used in the pretreatment process.

[0031] (3) The mass percentage of tin in the tantalum-niobium hydrometallurgical residue is about 10%. After the filter cake obtained by pretreatment filtration is pulped, it is enriched by gravity separation using a shaking table to recover tin. The heavy minerals enriched by gravity separation are collected and dehydrated to obtain tin concentrate. The mass percentage of tin is Sn≥40%, which can be sold as tin concentrate, realizing the comprehensive recovery of valuable tin resources in the ore extraction residue.

[0032] (4) The mass percentage of uranium in the ore extraction residue produced by tantalum-niobium hydrometallurgy is U > 0.1%, and it contains uranium tetrafluoride, uranyl sulfate, and uranyl fluoride. The purpose of pretreatment is to recover the uranyl-containing substances in the ore extraction residue, that is, to achieve the transformation of its hydrated uranyl fluoride crystals, and to remove UO2[SO4] entrained in the liquid phase. n 2-2n and UO2[F2] n 2-2n The process involves the transformation and comprehensive treatment and recovery of uranium. Simultaneously, it ensures that the concentration of radioactive uranium nuclides in the slag obtained from the comprehensive treatment of mining residues and their acidic wastewater is <1 Bq / g.

[0033] (5) Uranium is extracted by leaching using oxidation and alkaline methods, which can efficiently leach and separate uranium, improving the uranium leaching rate. The uranium-containing alkaline leaching solution is obtained by filtration, and the uranium is mainly Na4[UO2(CO3)3]. The alkaline leaching solution is subjected to alkaline precipitation, filtration and filter cake washing to obtain a filter cake containing uranium as a crude product. The residual fluorine in the crude uranium product is further removed by solid-liquid separation and filter cake washing, which is beneficial to the efficiency of subsequent ion exchange separation and extraction of uranium.

[0034] The precipitate mother liquor obtained from the filtration of the alkali-precipitated slurry is evaporated and concentrated, and then used as a precipitant for the alkali precipitation of the next batch of alkali leaching solution. This process is repeated to reduce the amount of precipitant required for alkali precipitation.

[0035] (6) Uranium-containing crude products are extracted by hydrochloric acid decomposition. The adsorption solution is prepared by adjusting the acidity and chloride ion content of the adsorption solution, and the H2O is preset. + >0.1mol / L, Cl - >4.5 mol / L, causing UO2Cl2 in the liquid phase to transform into [(UO2)Cl4] 2- This is beneficial for the adsorption, separation, and purification of uranium using 201×7 strongly basic anion exchange resin.

[0036] (7) Uranium is separated and purified by ion exchange method. The saturated resin is desorbed, neutralized and precipitated, filtered and the filter cake is washed to obtain qualified sodium diuranate product and recover uranium.

[0037] (8) This process is reasonable, the 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 tin and uranium resources associated with tantalum and niobium ore. Attached Figure Description

[0038] Figure 1 This is a schematic flowchart illustrating a method for the comprehensive recovery of tin and uranium from tantalum-niobium ore extraction residues provided by the present invention. Detailed Implementation

[0039] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0041] This invention provides a method for the comprehensive recovery of tin and uranium from the extraction residue of tantalum-niobium ore, specifically including the following steps:

[0042] S1. Pretreatment. The tantalum-niobium ore extraction residue is added to a reaction vessel containing industrial-grade sodium hydroxide solution. Stirring and heating are started for pretreatment. Sodium hydroxide is used as a pretreatment agent to pretreat the uranium in the extraction residue through transformation or conversion. A NaOH solution with a mass percentage concentration ≥30% is preferred. The final pH value is 13-14. Afterwards, the residue is filtered to separate a filter cake and a filtrate. The filter cake is washed to obtain wash water.

[0043] Specifically, based on the fact that the liquid phase entrainment of tantalum-niobium ore extraction residue contains not only high concentrations of residual sulfuric acid and hydrofluoric acid, but also a certain amount of uranyl sulfate (UO2SO4) and uranyl fluoride (UO2F2), by controlling the pH value at the neutralization and precipitation endpoint to 13-14, the sulfuric acid and hydrofluoric acid can be converted into sodium fluoride and sodium sulfate, respectively, and retained in the liquid phase. Sulfate and fluoride in the filter cake are removed by solid-liquid separation filtration and filter cake washing. At the same time, the uranyl sulfate and uranyl fluoride entrained in the liquid phase are converted into sodium diuranate and transferred to the solid phase, realizing the conversion and recovery of uranium entrained in the liquid phase.

[0044] Under high concentrations of hydrofluoric acid, uranium (VI) in the solid phase of mineral extraction residue is mainly hydrated uranyl fluoride crystals (UO2F2·nH2O), which are soluble substances. The conversion of uranyl fluoride is presumably carried out under relatively long time and certain alkaline conditions, which can completely convert the hydrated uranyl fluoride crystals into diuranate precipitates, which remain in the solid phase, thus achieving the transformation and recovery of uranium (VI) in the solid phase.

[0045] Since the pretreatment agent used is sodium hydroxide solution, and the pretreatment process includes acid-base neutralization reactions, all of which are exothermic reactions, the reaction temperature can be maintained at 40℃~65℃ within the required reaction time under good heat preservation conditions.

[0046] In summary, pretreatment of mineral extraction residues not only enables the recovery of uranium from uranyl fluoride and uranyl sulfate entrained in the liquid phase of the residues, improving uranium recovery rates, but also removes fluoride ions from the liquid phase through solid-liquid separation, facilitating subsequent ion exchange separation and uranium extraction. Furthermore, it completely converts soluble hydrated uranyl fluoride in the solid phase of the mineral extraction residues into diuranate, preventing the dissolution of soluble hydrated uranyl fluoride during washing of the residues, thus avoiding uranium loss and secondary pollution. The main reaction equations are as follows:

[0047] H₂SO₄ + 2NaOH = Na₂SO₄ + 2H₂O

[0048] HF + NaOH = NaF + H2O

[0049] 2UO2SO4 + 6NaOH = Na2U2O7↓+ 2Na2SO4 + 3H2O

[0050] 2UO2F2 + 6NaOH = Na2U2O7↓ + 4NaF + 3H2O

[0051] 2UO2F2·nH2O + 6NaOH = Na2U2O7 + 4NaF + (2n+3)H2O

[0052] The pretreated slurry is filtered and separated by a chamber filter press to obtain filtrate and filter cake. The filter cake is then washed with two-stage cross-flow washing to obtain wash water, which is tap water.

[0053] S2. Causticization treatment. The mixture of washing water and filtrate from S1 is placed in a reaction vessel and mixed. Stirring and heating are started. Industrial-grade calcium hydroxide powder is added, specifically the material passing through a -320 mesh sieve, with a Ca(OH)2 mass percentage ≥85.0%. The liquid-to-solid ratio of the mixture to industrial calcium hydroxide is controlled at 1L:(255g~305g). The causticization reaction temperature is controlled at 92℃~105℃ and the time is 2.0h~3.0h.

[0054] Under high-temperature conditions, sodium salt is replaced with sodium hydroxide through a causticization reaction. After the reaction is complete, the resulting slurry is subjected to solid-liquid separation using a chamber filter press. The filtered clear liquid contains sodium hydroxide, which is then concentrated by evaporation to a predetermined sodium hydroxide mass percentage of ≥30% (NaOH). This concentrated liquid is then returned for pretreatment to replace the sodium hydroxide solution. The main reaction equations are as follows:

[0055] Ca(OH)2 + Na2CO3 = CaCO3↓ + 2NaOH

[0056] Ca(OH)2 + NaHCO3 = CaCO3↓ + NaOH + H2O

[0057] S3. Gravity separation yields tin concentrate and tailings. Specifically, the filter cake washed in S1 is mixed with water to make a slurry with a mass percentage of 15%~25%. The slurry is subjected to gravity separation on a shaking table to collect the gravity-enriched heavy minerals. After dehydration, the main tin-containing minerals are obtained, and tin is recovered. The tin mass percentage is Sn≥40%, which can be sold as tin concentrate. The light minerals are collected from the shaking table and subjected to solid-liquid separation to obtain tailings, which are used for subsequent leaching to recover uranium.

[0058] Uranium is extracted using S4 leaching, oxidation, and alkaline methods. Specifically, the tailings from S3 are added to a reaction vessel containing the alkaline leaching agent. Stirring and heating are initiated, an oxidant is added, and the temperature continues to rise. The reaction temperature is controlled at 95℃±5℃ for 12-14 hours, with a final pH of 9.5-10.5. The solution is filtered to separate uranium-containing alkaline leaching solution and filter cake. The filter cake is washed to obtain wash water. The alkaline leaching solution and wash water are combined and subjected to sodium hydroxide alkali precipitation, filtration, and filter cake washing to obtain a crude uranium-containing product.

[0059] In a preferred embodiment, the alkaline leaching agent is a sodium carbonate (Na2CO3) solution with a mass percentage of 10%~20% and a sodium bicarbonate (NaHCO3) solution with a mass percentage of 5%~10%, and the liquid-solid ratio of the alkaline leaching agent to the tailings slag is (1.5~3.0) L:1kg; the oxidant is an industrial-grade sodium hypochlorite solution with available chlorine (calculated as Cl) Cl≥10%, and the liquid-solid ratio of the oxidant to the tailings slag is (0.025~0.100) L:1kg.

[0060] Based on the fact that the uranium in the tantalum-niobium ore extraction residue mainly consists of uranium tetrafluoride (UF4) and sodium diuranate (Na2U2O7), uranium was extracted from the residue using oxidation and alkaline methods. The alkaline leaching reaction temperature was controlled at 95℃±5℃, the leaching time at 12-14 h, and the final pH value at the leaching endpoint was 9.0-10.5. If the final pH value is too high, the uranium already in the solution will be precipitated by the alkaline solution and return to the solid phase, reducing the uranium leaching rate.

[0061] The purpose of alkaline leaching is to achieve stable oxidation and conversion of uranium under high temperature and alkaline conditions for a prolonged period, controlling the reaction rate and products. The reaction mechanism in this step involves uranium in the mineral extraction residue, primarily composed of uranium tetrafluoride and sodium diuranate. Uranium tetrafluoride requires high temperature and suitable pH conditions, through the combined action of an oxidant and an alkaline leaching agent over a long period, to oxidize U(Ⅳ) in uranium tetrafluoride to U(Ⅵ), which is then oxidized and converted into a soluble sodium uranyl tricarbonate solution. Simultaneously, neutralization and precipitation convert uranium in sodium diuranate into a soluble sodium uranyl tricarbonate solution. The sodium uranyl tricarbonate solution obtained from the above leaching process can be separated by plate and frame filtration and transferred to the liquid phase, achieving the goal of extracting and recovering uranium from the mineral extraction residue. The main reaction equations are as follows:

[0062] UF4+3Na2CO3+2NaHCO3+NaClO=Na4[UO2(CO3)3]+4NaF+NaCl+H2O+2CO2↑

[0063] Na2U2O7 + 6NaHCO3 = 2Na4[UO2(CO3)3] + 3H2O

[0064] The mixture of the above-obtained leachate and wash water was subjected to alkaline precipitation with sodium hydroxide to recover uranium. After the reaction was complete, the solution was filtered to obtain a filter cake containing uranium as a crude product. Fluorine in the filter cake was removed by filtration and filter cake washing. Specifically, the precipitant was a ≥30% NaOH solution, prepared from industrial-grade solid sodium hydroxide. The final pH value for complete alkaline precipitation was controlled at 13-14, the temperature at 50℃±5℃, and the time at 1.0h-1.5h. Fluorine entrained in the uranium-containing crude product was further removed by filtration and filter cake washing. The main chemical reaction equations are as follows:

[0065] 2Na4[UO2(CO3)3] + 6NaOH = Na2U2O7↓ + 6Na2CO3 + 3H2O

[0066] S5. Preparation of Acid Decomposition and Adsorption Stock Solution. Specifically, the uranium-containing crude product from S4 is decomposed with dilute hydrochloric acid to extract uranium. The leaching solution obtained by filtration is combined with the washing water and adjusted to prepare the adsorption stock solution. The uranium, hydrogen ion, and chloride ion content in the prepared adsorption stock solution is preset and adjusted. Specifically, the uranium-containing crude product (filter cake) obtained by filtration is placed in a reaction vessel containing dilute hydrochloric acid and heated and stirred. The leaching temperature is controlled at 40℃~60℃ and the time is 0.5h~1.5h. After filtration and filter cake washing, uranium-containing alkaline leaching solution, washing water, and filter residue are obtained. Preferably, the acid decomposition agent is a (15%~25%) HCl solution, and the liquid-solid ratio of the dilute hydrochloric acid solution required for acid decomposition to the filter residue is (3.0~5.0) L:1kg. After solid-liquid separation of the acid decomposition solution, the filter cake is washed to obtain washing water. The washing water is mixed with the acid decomposition solution, and the H+ content in the mixture is adjusted. + and Cl - The concentration was prepared to obtain [UO2Cl4] 2- The adsorption stock solution. Specifically, it is necessary to pre-test the concentrations of uranium, hydrogen, and chloride ions in the combined solution of washing water and acid decomposition solution, and adjust the preparation of the adsorption stock solution to meet the conditions required for ion exchange. The uranium concentration of the adsorption stock solution was tested to be U: 0.5 g / L~2.0 g / L, H: 0.5 g / L~2.0 g / L, and the chloride ion concentration was H: 0.5 g / L~2.0 g / L. + >0.1mol / L, Cl - >4.5 mol / L, only after passing the test can the next process proceed; if it does not meet the requirement, the adsorption stock solution needs to be prepared and treated again. In a hydrochloric acid system, when the chloride ion concentration Cl... - When the concentration is >4.5 mol / L, the UO2Cl2 and Cl in the leachate - A complexation reaction occurs, forming [UO2Cl4], which is conducive to ion exchange and adsorption. 2- The main chemical reaction equations are as follows:

[0067] Na2U2O7 + 6HCl = 2UO2Cl2 + 2NaCl + 3H2O

[0068] UO2Cl2 + 2Cl - = [UO2Cl4] 2-

[0069] S6. Ion exchange separation and purification of uranium, and neutralization precipitation for uranium recovery. Specifically, the adsorbent solution in S5 is used to separate and purify uranium using ion exchange. After rinsing, a qualified uranium-containing solution is obtained. Uranium is then recovered through neutralization precipitation. After filtration, the filter cake is washed to obtain sodium diuranate product and uranium is recovered.

[0070] In a preferred embodiment, the ion exchange resin used is a 201×7 strongly basic anion exchange resin. When the adsorption stock solution comes into contact with the resin, uranyl chloride anions undergo ion exchange with the amino groups in the resin, causing uranium in the adsorption stock solution to accumulate in the resin. After removing impurities by washing with an acid wash containing the same concentration of chloride as the adsorption stock solution, the uranium in the resin is desorbed into the aqueous phase using a 0.1 mol / L HCl solution or pure water to obtain a qualified solution with the ideal uranium concentration. The resin adsorption and determination of whether the uranium-containing eluent is a qualified uranium solution are performed. Eluent that does not meet the uranium qualified solution standard is returned to step 4 for hydrochloric acid acidification to adjust the preparation of the adsorption stock solution. The judgment criteria are: the uranium content U in the qualified uranium eluent should be ≥20 g / L, and the uranium content U in the adsorption tail liquid should be <20 mg / L. The reaction equation is as follows:

[0071] 2(RN)Cl + [UO2Cl4] 2- → (RN)2[UO2Cl4] + 2Cl -

[0072] (RN)2[UO2Cl4] → 2(RN)Cl + UO2Cl2

[0073] The neutralization precipitation process for uranium recovery specifically involves using a NaOH solution with a mass percentage of ≥30% to neutralize and precipitate uranium in a qualified uranium solution. The reaction temperature is controlled at 65℃±5℃, the precipitation time at 4-6 hours, and the pH at 6.5-7.5. This yields a neutralized precipitate slurry, which is then aged and separated by sedimentation. The underflow slurry after sedimentation is filtered through a plate and frame filter press to obtain a filter cake. The filter cake is then washed to remove residual mother liquor, resulting in the target sodium diuranate product. This ensures that the prepared sodium diuranate product meets the requirements of the "Technical Conditions for Diuranates" (EJ / T803-93).

[0074] To better illustrate the above reaction effects, specific examples and comparative examples are provided below for further explanation.

[0075] Example 1

[0076] Take a sample of tantalum-niobium ore extraction residue, U （干基）:0.61%, Sn: 9.84%, H2O: 20.82%.

[0077] S1. Take a 1000ml polytetrafluoroethylene beaker, add 600ml of 31.01% NaOH solution to the beaker, start stirring, add the tantalum-niobium ore extraction residue, and at the same time observe the pH value of the solution and the temperature of the reaction material by pH meter. When the pH value drops to 14, slowly add the extraction residue. The pH value of the neutralization and precipitation endpoint is 13.5. Record the amount (g) of extraction residue (wet residue) added.

[0078] The feed solution, adjusted to the final pH value, was stirred continuously, with the pretreatment reaction temperature controlled at 45℃±2℃ and the time at 4.0h. The pretreated slurry was then transferred to a chamber filter press for solid-liquid separation to obtain a filter cake. The filter cake pulping was subjected to two stages of water washing to remove sulfate and fluoride ions entrained in the liquid phase of the filter cake.

[0079] S2: Take a 1000ml stainless steel measuring cup and place 600ml of the mixture of washing water and filtrate into a reaction vessel. Mix, turn on stirring and heat, and gradually add 180g of industrial calcium hydroxide powder. The reaction temperature is 95℃±2℃, and the reaction time is 3.0h. After naturally cooling to ≤60℃, filter the solution. Measure and record the volume (ml) of the filtrate and the mass percentage of sodium hydroxide solution (NaOH: 31.20%) at room temperature. This solution can be returned to S1 to replace part of the industrial-grade liquid sodium hydroxide.

[0080] S3: The filter cake washed in S1 is pulped with water until the slurry mass percentage is 15.92%. The slurry is then subjected to gravity separation using a shaking table. The gravity-enriched heavy minerals are collected to obtain tin concentrate. The weight (g), moisture (%), and tin mass percentage Sn (41.21%) of the tin concentrate are measured and recorded. The light minerals collected from the shaking table are then subjected to solid-liquid separation to obtain tailings. The weight (g), moisture (%), and uranium mass percentage U of the tailings are measured and recorded. （干基） : 0.51%.

[0081] For S4, take a 1000ml beaker, add 500ml of a mixture of 18.04% Na2CO3 and 5.26% NaHCO3, turn on the stirrer and heat (water bath heating), slowly add 300g of S3 tailings slag (wet slag), and add 10ml of industrial-grade NaClO solution. The reaction temperature for oxidation and alkaline leaching is 95℃±2℃, and the heating and stirring is carried out for 14h. After filtration and filter cake washing, obtain the leachate and wash water. Measure and record the volume (ml) of the alkaline leachate, the pH value of which is 10.1, and the volume (ml) of the wash water.

[0082] The obtained alkaline leaching solution and wash water were combined in a 1000 ml beaker, stirred and heated. Industrial-grade 31.28% NaOH solution was added for neutralization and precipitation to recover uranium. The temperature was controlled at 50℃±2℃ for 1.0 h, with a final pH of 13.5. The solution was filtered to obtain a crude uranium-containing filter cake. Fluorine entrained in the crude uranium-containing product was removed by filtration and filter cake washing. The weight (g) of the uranium-containing crude product after washing was measured and recorded.

[0083] S5, take a 1000ml beaker, add 600ml of 15.61% HCl solution, start stirring and heat, gradually add 150g of uranium-containing crude product (filter cake), control the acid decomposition temperature at 50℃±2℃ and the time at 1.5h; after solid-liquid separation of the acid decomposition solution, wash the filter cake to obtain wash water, mix the wash water with the acid decomposition solution, and adjust to prepare the adsorption stock solution. Measure the adsorption stock solution U: 0.98g / L, H... + 0.35 mol / L, Cl - 4.92 mol / L, to be used.

[0084] S6. Uranium in the above-mentioned adsorption stock solution was purified and separated using a 201×7 strongly basic anion exchange resin, yielding uranium-containing saturated resin and adsorption tail liquid. The adsorption tail liquid U was measured to be 10.62 mg / L. The uranium-containing saturated resin was leached to obtain a uranium-compliant eluent with U ≥ 20 g / L. The volume (ml) of the uranium-compliant eluent was measured and recorded, and the uranium-compliant eluent U was measured to be 26.86 g / L. 31.01% NaOH was used as the precipitant, with a precipitation temperature of 65℃±2℃, a precipitation time of 4.0 h, and a pH of 7.2. The precipitate slurry underwent multiple batch aging treatments. The underflow slurry after sedimentation and separation was vacuum filtered through a Buchner funnel. One pulping and washing 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," which is the sodium diuranate product.

[0085] The obtained sodium diuranate product was tested, and the results are as follows: On a dry basis, the mass percentage of each element or substance is: U: 53.32%, SO42- 2- 0.32%, PO4 3- 0.19%, SiO2: 0.25%, F-: 0.18%, Cl-: 0.16%. Meets the requirements of "Technical Conditions for Diuranates" (EJ / T803-93).

[0086] Example 2

[0087] Take a sample of tantalum-niobium ore extraction residue, U (干基) :1.02%, Sn: 12.51%, H2O: 30.12%.

[0088] S1. Take a 1000ml polytetrafluoroethylene beaker, add 600ml of 30.58% NaOH solution to the beaker, start stirring, add tantalum-niobium ore extraction residue, and at the same time observe the pH value of the solution and the temperature of the reaction material by pH meter. When the pH value drops to 14, slowly add the ore extraction residue. The pH value of the neutralization and precipitation endpoint is 13.9. Record the amount (g) of ore extraction residue (wet residue) added.

[0089] The feed solution, adjusted to the final pH value, was stirred continuously, with the pretreatment reaction temperature controlled at 55℃±2℃ and the time at 3.5h. The pretreated slurry was then transferred to a chamber filter press for solid-liquid separation to obtain a filter cake. The filter cake was then subjected to two stages of water washing to remove sulfate and fluoride ions entrained in the liquid phase.

[0090] S2: Take a 1000ml stainless steel measuring cup and place 600ml of the mixture of washing water and filtrate into a reaction vessel. Mix, turn on the stirrer and heat, and gradually add 180g of industrial calcium hydroxide powder. The reaction temperature is 98℃±2℃, and the reaction time is 2.5h. After naturally cooling to ≤60℃, filter the solution. Measure and record the volume (ml) of the filtrate and the mass percentage of sodium hydroxide solution (NaOH: 32.09%) at room temperature. This solution can be returned to S1 to replace part of the industrial-grade liquid sodium hydroxide.

[0091] S3: The filter cake washed in S1 is pulped with water until the slurry mass percentage is 18%. The slurry is then subjected to gravity separation using a shaking table. The gravity-enriched heavy minerals are collected to obtain tin concentrate. The weight (g), moisture (%), and tin mass percentage Sn (43.06%) of the tin concentrate are measured and recorded. The light minerals collected from the shaking table are then subjected to solid-liquid separation to obtain tailings. The weight (g), moisture (%), and uranium mass percentage U of the tailings are measured and recorded. （干基） : 0.89%.

[0092] For S4, take a 1000ml beaker, add 500ml of a mixed solution of 15.98% Na2CO3 and 8.56% NaHCO3, turn on the stirrer and heat (water bath heating), slowly add 300g of S3 tailings slag (wet slag), and add 20ml of industrial grade NaClO solution. The reaction temperature for oxidation and alkaline leaching is 95℃±2℃, and the heating and stirring is carried out for 12h. After filtration and filter cake washing, obtain leachate and wash water. Measure and record the volume (ml) of alkaline leachate, the pH value of which is 9.8, and the volume (ml) of wash water.

[0093] The obtained alkaline leaching solution and wash water were combined in a 1000ml beaker, stirred and heated. Industrial-grade 31.28% NaOH solution was added for neutralization and precipitation to recover uranium. The temperature was controlled at 52℃±2℃ for 1.5 hours, with a final pH of 13.2. The solution was filtered to obtain a crude uranium-containing filter cake. Fluorine entrained in the crude uranium-containing product was removed by filtration and filter cake washing. The weight (g) of the uranium-containing crude product after washing was measured and recorded.

[0094] S5, take a 1000ml beaker, add 600ml of 20.12% HCl solution, start stirring and heat, gradually add 150g of uranium-containing crude product (filter cake), control the acid decomposition temperature at 55℃±2℃ and the time at 1.0h; after solid-liquid separation of the acid decomposition solution, wash the filter cake to obtain wash water, mix the wash water with the acid decomposition solution, and adjust to prepare the adsorption stock solution. Measure the adsorption stock solution U: 1.32g / L, H... + 0.51 mol / L, Cl - 4.87 mol / L, to be used.

[0095] S6. Uranium in the above-mentioned adsorption stock solution was purified and separated using a 201×7 strongly basic anion exchange resin, yielding uranium-containing saturated resin and adsorption tail liquid. The adsorption tail liquid U was measured to be 15.41 mg / L. The uranium-containing saturated resin was leached to obtain a uranium-compliant eluent with U ≥ 20 g / L. The volume (ml) of the uranium-compliant eluent was measured and recorded, and the uranium-compliant eluent U was measured to be 22.21 g / L. 30.58% NaOH was used as the precipitant, with a precipitation temperature of 65℃±2℃, a precipitation time of 5.0 h, and a pH of 6.8. The precipitate slurry underwent multiple batch aging treatments. The underflow slurry after sedimentation and separation was vacuum filtered through a Buchner funnel. One pulping and washing 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," which is the sodium diuranate product.

[0096] The obtained sodium diuranate product was tested, and the results are as follows: On a dry basis, the mass percentage of each element or substance is: U: 56.37%, SO42-22-3 ... 2- 0.98%, PO4 3- 0.11%, SiO2: 0.36%, F - 0.12%, Cl - 0.15%. Meets the requirements of the "Technical Conditions for Diuranates" (EJ / T803-93).

[0097] Example 3

[0098] Take a sample of tantalum-niobium ore extraction residue, U (干基) :0.39%, Sn: 10.09%, H2O: 20.16%.

[0099] S1. Take a 1000ml polytetrafluoroethylene beaker, add 600ml of 30.67% NaOH solution to the beaker, start stirring, add tantalum-niobium ore extraction residue, and at the same time observe the pH value of the solution and the temperature of the reaction material by pH meter. When the pH value drops to 14, slowly add the ore extraction residue. The pH value of the neutralization and precipitation endpoint is 13.7. Record the amount of ore extraction residue (wet residue) added (g).

[0100] The feed solution, adjusted to the final pH value, was stirred continuously, with the pretreatment reaction temperature controlled at 60℃±2℃ and the time at 3.0h. The pretreated slurry was transferred to a chamber filter press for solid-liquid separation to obtain a filter cake. The filter cake was then subjected to two stages of water washing to remove sulfate and fluoride ions entrained in the liquid phase.

[0101] S2: Take a 1000ml stainless steel measuring cup and place 600ml of the mixture of washing water and filtrate into a reaction vessel. Mix, turn on the stirrer and heat, and gradually add 180g of industrial calcium hydroxide powder. The reaction temperature is 102℃±2℃, and the reaction time is 2.0h. After naturally cooling to ≤60℃, filter the solution. Measure and record the volume (ml) of the filtrate and the mass percentage of sodium hydroxide solution at room temperature (NaOH: 30.86%). This solution can be returned to S1 to replace part of the industrial-grade liquid sodium hydroxide.

[0102] S3. The filter cake washed in S1 is pulped with water until the slurry mass percentage is 20.18%. The slurry is then subjected to gravity separation using a shaking table. The gravity-enriched heavy minerals are collected to obtain tin concentrate. The weight (g), moisture (%), and tin mass percentage Sn (41.95%) of the tin concentrate are measured and recorded. The light minerals collected from the shaking table are then subjected to solid-liquid separation to obtain tailings. The weight (g), moisture (%), and uranium mass percentage U of the tailings are measured and recorded. （干基） : 0.34%.

[0103] S4. Take a 1000ml beaker, add 500ml of a mixture of 14.50% Na2CO3 and 9.82% NaHCO3, turn on the stirrer and heat (water bath heating), slowly add 300g of tailings slag (wet slag) from step 3, and add 25ml of industrial-grade NaClO solution. The reaction temperature for oxidation and alkaline leaching is 95℃±2℃, and the heating and stirring is carried out for 13h. After filtration and filter cake washing, obtain leachate and wash water. Measure and record the volume (ml) of alkaline leachate, the pH value of which is 10.4, and the volume (ml) of wash water.

[0104] The obtained alkaline leaching solution and wash water were combined in a 1000 ml beaker, stirred and heated. Industrial-grade 31.28% NaOH solution was added for neutralization and precipitation to recover uranium. The temperature was controlled at 50℃±2℃ for 0.8 h, with a final pH of 13.6. The solution was filtered to obtain a crude uranium-containing filter cake. Fluorine entrained in the crude uranium-containing product was removed by filtration and filter cake washing. The weight (g) of the uranium-containing crude product after washing was measured and recorded.

[0105] S5, take a 1000ml beaker, add 600ml of 24.01% HCl solution, start stirring and heat, gradually add 150g of uranium-containing crude product (filter cake), control the acid decomposition temperature at 50℃±2℃ and the time at 1.0h; after solid-liquid separation of the acid decomposition solution, wash the filter cake to obtain wash water, mix the wash water with the acid decomposition solution, and adjust to prepare the adsorption stock solution. Measure the adsorption stock solution U: 0.82g / L, H... + 0.40 mol / L, Cl - 4.59 mol / L, ready for use.

[0106] S6. Uranium in the above-mentioned adsorption stock solution was purified and separated using a 201×7 strongly basic anion exchange resin, yielding uranium-containing saturated resin and adsorption tail liquid. The adsorption tail liquid U was measured to be 8.76 mg / L. The uranium-containing saturated resin was leached to obtain a uranium-compliant eluent with U ≥ 20 g / L. The volume (ml) of the uranium-compliant eluent was measured and recorded, and the uranium-compliant eluent U was measured to be 23.32 g / L. 30.67% NaOH was used as the precipitant, with a precipitation temperature of 65℃±2℃, a precipitation time of 6.0 h, and a pH of 7.4. The precipitate slurry underwent multiple batch aging treatments. The underflow slurry after sedimentation and separation was vacuum filtered through a Buchner funnel. One pulping and washing 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," which is the sodium diuranate product.

[0107] The obtained sodium diuranate product was tested, and the results are as follows: On a dry basis, the mass percentage of each element or substance is: U: 51.62%, SO42- 2- 0.25%, PO4 3- 0.28%, SiO2:0.45%, F - 0.10%, Cl - 0.15%. Meets the requirements of the "Technical Conditions for Diuranates" (EJ / T803-93).

[0108] To verify the effect of the pH value at the leaching endpoint in step S4 on the uranium leaching rate, the following comparative examples 1 and 2 were set up.

[0109] Comparative Example 1

[0110] The difference from Example 1 is that the pH value at the leaching endpoint in step S4 is 11.0, while the other conditions are the same as in Example 1. The leaching rate is about 28% lower than that under normal operation.

[0111] Comparative Example 2

[0112] The difference from Example 1 is that the pH value at the leaching endpoint in step S4 is 11.5, while the other conditions are the same as in Example 1. The leaching rate is about 45% lower than that under normal operation.

[0113] Comparative Example 3

[0114] The difference from Example 1 is that the pH value at the leaching endpoint in step S4 is 13.0, while the other conditions are the same as in Example 1. The leaching rate is about 99.8% lower than that under normal operation.

[0115] Comparing Comparative Examples 1, 2, and 3 with Example 1, it can be seen that when the pH value at the leaching endpoint is too high, greater than 10.5, the uranium that has entered the solution will be precipitated by alkali and return to the solid phase due to the high pH value of the solution, thus reducing the uranium leaching rate. When the pH value reaches 13.0, the uranium that has been decomposed will be precipitated as diuranate due to the increase in solution pH and returned to the solid phase.

[0116] Comparative Example 4

[0117] The difference from Example 1 is that in step S4, the liquid-solid ratio of the oxidant (sodium hypochlorite) to the tailings slag is 0.015L:1kg, and the other conditions are the same as in Example 1, with a uranium leaching rate of 55%.

[0118] Comparative Example 5

[0119] The difference from Example 1 is that in step S4, the liquid-to-solid ratio of the oxidant (sodium hypochlorite) to the tailings slag is 0.020L:1kg, and the other conditions are the same as in Example 1, with a uranium leaching rate of 82%.

[0120] As can be seen from the comparison of Comparative Examples 4 and 5 with Example 1, when the liquid-solid ratio of the oxidant (sodium hypochlorite) to the tailings slag is low, below 0.025L:1kg, the leaching rate will be low because some U(Ⅳ) in the material will not be oxidized to U(Ⅵ) due to insufficient oxidant.

[0121] Comparative Example 6

[0122] The difference from Example 1 is that the reaction temperature for uranium extraction by oxidation and alkaline leaching in step S4 is 75℃±2℃, while other conditions are the same as in Example 1, and the uranium leaching rate is ~38%.

[0123] Comparative Example 7

[0124] The difference from Example 1 is that the reaction temperature for uranium extraction by oxidation and alkaline leaching in step S4 is 85℃±2℃, while other conditions are the same as in Example 1, and the uranium leaching rate is ~87%.

[0125] As can be seen from the comparison of Comparative Examples 6 and 7 with Example 1, when the reaction temperature is low, below 95°C, the leaching rate will be low due to the low reaction temperature.

[0126] In summary, by controlling specific processing conditions and coordinating the various steps, this invention can efficiently recover tin and uranium from the extraction residue of tantalum-niobium ore, thus achieving comprehensive recovery and utilization of tin and uranium in tantalum-niobium ore resources.

[0127] 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.

[0128] When a parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1~5” is disclosed, the described range should be interpreted as including the ranges “1~4”, “1~3”, “1~2”, “1~2 and 4~5”, “1~3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0129] 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 the comprehensive recovery of tin and uranium from the extraction residue of tantalum-niobium ore, characterized in that, The method includes the following steps: S1. Add the tantalum-niobium ore extraction residue to a sodium hydroxide solution, stir and heat for pretreatment, control the pretreatment reaction temperature to 40℃~65℃, the time to 3.0h~4.0h, and the final pH value to 13~14, then filter to separate the filter cake and filtrate, and wash the filter cake to obtain wash water and washed filter cake. S2. Mix the washing water and filtrate from S1, and perform causticization treatment with calcium hydroxide. Control the causticization reaction temperature to be 92℃~105℃ and the time to be 2.0h~3.0h. After the reaction is completed, filter the slurry to obtain a filtrate containing sodium hydroxide. After evaporation and concentration, return it to S1 for pretreatment to replace the sodium hydroxide solution. S3. The washed filter cake from S1 is pulped and enriched by gravity separation on a shaking table to obtain tin concentrate and recover tin. The tailings obtained from gravity separation are used for uranium extraction and recovery; S4. Uranium is extracted from the tailings slag in S3 by oxidation and alkaline leaching. The leaching solution is filtered to obtain uranium-containing alkaline leaching solution. The filter cake is washed to obtain wash water. The alkaline leaching solution and wash water are combined and subjected to sodium hydroxide alkali precipitation, filtration and filter cake washing to obtain uranium-containing crude product. S5. Uranium-containing crude product from S4 is extracted using acid decomposition. The solution is filtered to obtain acid decomposition liquid, and the filter cake is washed to obtain wash water. The acid decomposition liquid and wash water are combined and adjusted to prepare the adsorption stock solution. S6. The adsorbent solution in S5 is separated and purified by ion exchange. The uranium-containing qualified solution is obtained by rinsing. The uranium is recovered by neutralization and precipitation. After filtration, the filter cake is washed to obtain sodium diuranate product and the uranium is recovered.

2. The method for comprehensively recovering tin and uranium from tantalum-niobium ore extraction residue according to claim 1, characterized in that, In S1, a NaOH solution with a mass percentage concentration of ≥30% is used; the pretreated slurry is filtered and separated by a chamber filter press to obtain filtrate and filter cake. The filter cake is pulped and washed with two-stage cross-flow washing to obtain wash water, which is tap water.

3. The method for comprehensively recovering tin and uranium from tantalum-niobium ore extraction residue according to claim 1, characterized in that, In S2, the filtrate and wash water are mixed in a reaction vessel, stirred and heated, and industrial calcium hydroxide powder is gradually added. The industrial calcium hydroxide powder is selected from -320 mesh sieves and has a mass percentage ≥85.0%. Sodium carbonate is replaced with sodium hydroxide through causticization treatment. The slurry is filtered to obtain a filtrate containing sodium hydroxide, which is evaporated and concentrated to a sodium hydroxide mass percentage ≥30% and returned to S1 to prepare the sodium hydroxide solution required for pretreatment.

4. The method for comprehensively recovering tin and uranium from tantalum-niobium ore extraction residue according to claim 1, characterized in that, The S3 process is as follows: The filter cake after washing S1 is mixed with water to make a slurry, and the mass percentage of the slurry is controlled at 15%~25%; the slurry is subjected to gravity separation through a shaking table, the gravity-enriched heavy minerals are collected, and the main tin-containing minerals are obtained after dehydration. Tin is recovered, and the mass percentage of tin is ≥40%, which can be sold as tin concentrate; the light minerals are collected from the shaking table, and the tailings are obtained through solid-liquid separation.

5. The method for comprehensively recovering tin and uranium from tantalum-niobium ore extraction residue according to claim 1, characterized in that, The specific reaction process of S4 is as follows: the tailings slag is put into a reaction vessel containing the alkaline leaching agent, stirring is started and heating is carried out, an oxidant is added, the temperature is continued to rise, the reaction temperature is controlled at 95℃±5℃, the time is 12h~14h, the final pH value is 9.5~10.5, and the liquid is filtered to obtain uranium-containing alkaline leaching solution and filter cake.

6. The method for comprehensively recovering tin and uranium from tantalum-niobium ore extraction residue according to claim 5, characterized in that, The alkaline leaching agent is a sodium carbonate solution with a mass percentage of 10%~20% and a sodium bicarbonate solution with a mass percentage of 5%~10%, and the liquid-solid ratio of the leaching agent to the tailings slag is (1.5~3.0) L:1kg. The oxidant used is sodium hypochlorite solution with an effective chlorine content ≥10%, and the liquid-to-solid ratio of the oxidant to the tailings slag is (0.025~0.100) L:1kg.

7. The method for comprehensively recovering tin and uranium from tantalum-niobium ore extraction residue according to claim 1, characterized in that, In S4, the over-alkali precipitation process is as follows: The mixture obtained by combining the alkaline leaching solution and the washing water is placed in a reaction vessel, stirring is started and heating is carried out. Sodium hydroxide solution is used as a precipitant for over-alkali precipitation to recover uranium. The mass percentage of sodium hydroxide solution is ≥30%. The over-alkali precipitation reaction temperature is controlled at 50℃±5℃, the time is 1.0h~1.5h, and the final pH value is 13~14. After that, the solution is filtered, and the filter cake after washing is the crude product containing uranium. The precipitate mother liquor obtained by filtration is concentrated by evaporation and used as a precipitant for the over-alkali precipitation of the next batch of alkaline leaching solution.

8. The method for comprehensively recovering tin and uranium from tantalum-niobium ore extraction residue according to claim 1, characterized in that, In S5, uranium-containing crude product is extracted by acid decomposition with dilute hydrochloric acid. The mass percentage of the dilute hydrochloric acid solution is 15%~25%, and the liquid-to-solid ratio of dilute hydrochloric acid to filter cake is (2.0~4.0) L:1kg. The acid decomposition temperature is controlled at 40℃~60℃ and the time is 0.5h~1.5h. The uranium-containing acid decomposition solution obtained by filtration is combined with the wash water, and the pH value, uranium and chloride ion concentrations of the solution are adjusted to prepare the adsorption stock solution. In the preset adsorption stock solution, the concentration of U is 0.5~2.0 g / L, and the concentration of H is... + >0.1mol / L, Cl - >4.5mol / L.

9. The method for comprehensively recovering tin and uranium from tantalum-niobium ore extraction residue according to claim 1, characterized in that, In S6, uranium was separated and extracted using a 201×7 strong basic anion exchange resin to obtain uranium-containing saturated adsorption resin and adsorption tail liquid. The saturated adsorption resin was washed to obtain a qualified uranium-containing solution with a uranium content U≥20g / L and a uranium content U≤20mg / L in the adsorption tail liquid.

10. The method for comprehensively recovering tin and uranium from tantalum-niobium ore extraction residue according to claim 1, characterized in that, In S6, the qualified uranium-containing liquid is neutralized and precipitated with sodium hydroxide solution to recover uranium. The mass percentage of NaOH solution is ≥30%. The precipitated slurry is then aged and separated by sedimentation. The sedimented underflow slurry is filtered through a chamber filter press to obtain a filter cake. The filter cake is washed to remove mother liquor residue and obtain the target sodium diuranate product.

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