Method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore

Abstract

The invention discloses a method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore, which comprises the following steps: grinding the associated tantalum-niobium ore to a preset particle size, carrying out heating reaction on the ground associated tantalum-niobium ore and a dilute sulfuric acid solution to obtain a leaching solution containing uranium, thorium and rare earth, and then carrying out solid-liquid separation to obtain a leaching solution clear solution and a filter cake; adding a sodium hydroxide solution into the leachate clear liquid, controlling the pH value, then separating and extracting uranium by adopting 201 * 7 strongly basic anion exchange resin to obtain uranium saturated resin and adsorption tail liquid, leaching the uranium saturated resin to obtain uranium leaching qualified liquid, and precipitating the uranium leaching qualified liquid through sodium hydroxide to obtain sodium diuranate; carrying out extraction treatment on the adsorption tail liquid to obtain a saturated organic phase and raffinate; carrying out back extraction treatment on the saturated organic phase to obtain thorium carbonate back water, and carrying out sulfuric acid precipitation to obtain thorium sulfate; and adding a sodium carbonate solution into the raffinate for neutralization and precipitation, and filtering to obtain the rare earth carbonate. The method aims at improving the metal extraction rate of the associated tantalum-niobium ore.

Description

Technical Field

[0001] The invention relates to the technical field of tantalum-niobium ore smelting, and in particular to a method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore. Background Art

[0002] Tantalum-niobium ores are usually accompanied by valuable resources such as uranium, thorium, and rare earths. In addition, high-concentration hydrofluoric acid-sulfuric acid is generally used as a leaching agent to extract tantalum-niobium resources for tantalum-niobium hydrometallurgical industrial production, and the associated resources such as uranium, thorium, and rare earths in tantalum-niobium ores are not recycled. As a result, part of the uranium, thorium, and rare earths in the tantalum-niobium ores are inevitably dissolved, and waste slag is formed after wastewater treatment, which is a radioactive hazardous waste slag; another part of uranium, thorium, and rare earths form fluoride salt waste slag, which is difficult to recycle; not only does it cause a waste of strategic resources, but it also increases the difficulty and cost of wastewater and waste slag treatment and environmental risks. Among them, the associated tantalum-niobium ores contain metals such as uranium, thorium, and rare earths, and their corresponding mass fractions are U3O8: 0.32%~4.84%, ThO2: 0.16%~1.57%, and RE2O3: 8.64%~20.96%.

[0003] The existing invention patent with patent publication number CN 106676291 A discloses a method for comprehensive recovery of uranium, niobium and tantalum from ores. The method adopts a low-concentration hydrofluoric acid-sulfuric acid system to simultaneously leach uranium, niobium and tantalum. However, compared with the existing tantalum-niobium production that adopts a high-concentration hydrofluoric acid-sulfuric acid system to simultaneously leach niobium and tantalum, there are still problems such as low tantalum-niobium leaching rate and imperfect resource recovery. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for recovering uranium, thorium and rare earth from associated tantalum-niobium ores, aiming to solve the technical problem of low recovery and extraction rate of associated ores in existing tantalum-niobium ores.

[0005] To achieve the above object, the present invention provides a method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore, the method comprising the following steps:

[0006] Step 1, grinding the associated tantalum-niobium ore into tantalum-niobium ore powder of a preset particle size, and heating and reacting with a dilute sulfuric acid solution for a preset time to obtain a leaching solution containing uranium, thorium and rare earth, wherein the volume mass ratio of the sulfuric acid solution to the tantalum-niobium ore powder is (1.5-2.0):1;

[0007] Step 2, performing solid-liquid separation on the uranium, thorium and rare earth leaching solution to obtain a leaching solution clear liquid and a filter cake, wherein the filter cake contains tantalum and niobium;

[0008] Step 3, adding sodium hydroxide solution to the clear solution of the leaching solution, and controlling the pH value to be 1.8-2.2, to obtain a uranium adsorption stock solution;

[0009] Step 4, separating and extracting uranium from the uranium adsorption stock solution using 201×7 strong alkaline anion exchange resin to obtain uranium saturated resin and adsorption tail liquid, eluting the uranium saturated resin to obtain eluted uranium qualified liquid, and precipitating with sodium hydroxide to obtain sodium diuranate;

[0010] Step 5, extracting the adsorption tail liquid to obtain a saturated organic phase and raffinate water;

[0011] Step 6, stripping the saturated organic phase to obtain thorium carbonate water, and then precipitating with sulfuric acid to obtain thorium sulfate;

[0012] Step 7, adding sodium carbonate solution to the raffinate water for neutralization and precipitation, and filtering to obtain rare earth carbonate.

[0013] Optionally, in step 2, the filter cake is subjected to multi-stage countercurrent washing to obtain entrained leachate, and the washing water is incorporated into the clear leachate to prepare a uranium adsorption stock solution.

[0014] Optionally, in step 1, the particle size of the tantalum-niobium ore powder is less than 200 mesh.

[0015] Optionally, in step 1, the reaction temperature is 85°C±5°C, and the reaction time is 6h to 10h.

[0016] Optionally, in step 4, the uranium saturated resin is rinsed with slightly acidic water.

[0017] Optionally, in step 5, the extractant is primary amine, the extraction system is 5% primary amine + 5% mixed alcohol + 90% sulfonated kerosene, and the O / A ratio of the organic phase to the aqueous phase is 1 / 4.

[0018] Optionally, in step 6, the stripping agent is a 2 mol / L (NH4)2CO3 solution, and the O / A ratio between the organic phase and the aqueous phase is (25-35) / 1.

[0019] Optionally, in step 7, 20% Na2CO3 is added to the raffinate water, and the pH value of the neutralization precipitate is controlled to be 6.8-7.5.

[0020] Optionally, in step 1, the dilute sulfuric acid is prepared by using concentrated sulfuric acid to prepare a 10% to 12% H2SO4 solution.

[0021] Optionally, in step 2, a chamber filter press is used to separate the solid and liquid of the leachate.

[0022] Beneficial effects:

[0023] The present invention is to add a certain amount of dilute sulfuric acid to the associated tantalum-niobium ore for leaching, control the leaching reaction conditions, and obtain a leachate containing uranium, thorium, and rare earths; adjust the acidity of the clear solution of the leachate to prepare a uranium adsorption stock solution, separate and extract uranium through 201×7 strong alkaline anion exchange resin, and recover uranium through precipitation; use primary amine extraction to separate and extract thorium from the uranium adsorption tail liquid, and recover thorium through acid precipitation; use sodium carbonate to precipitate and recover rare earths from the thorium extraction residual water, so that tantalum and niobium in the tantalum-niobium ore can be enriched. It not only realizes the recycling of strategic resources such as uranium, thorium, and rare earths, but also reduces the amount of high-concentration hydrofluoric acid-sulfuric acid required in the decomposition process of tantalum-niobium ore, and effectively reduces the cost of neutralizing the decomposition residual acid and acidic leaching water during the acid decomposition of the ore and the treatment of acidic wastewater. The entire process technology is reliable, easy to operate, and easy to achieve large-scale production. The quality of the sodium diuranate product meets the standard requirements of the "Technical Conditions for Diuranates" (EJ / T803-93). The rare earth carbonate produced can be used as a production raw material for rare earth separation enterprises, and then efficiently recover strategic resources such as uranium, thorium, and rare earths from associated tantalum-niobium ores. It is green and environmentally friendly and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of an embodiment of a method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to the present invention;

[0025] Figure 2 for Figure 1 The flow chart shown.

[0026] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0028] See also Figure 1-2 The present invention provides a schematic flow diagram of a method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore, the method comprising the following steps:

[0029] Step 1: Grind the associated tantalum-niobium ore into tantalum-niobium ore powder of a preset particle size, and heat it with a dilute sulfuric acid solution for a preset reaction time to obtain a leaching solution containing uranium, thorium and rare earth.

[0030] Among them, the associated tantalum-niobium ore components include Ta2O5: 20.00% to 50.00%, Nb2O5: 10.00% to 22.00%, U3O8: 0.32% to 4.84%, ThO2: 0.16% to 1.57%, RE2O3: 8.64% to 20.96%. In actual application, the associated tantalum-niobium ore is ground to a particle size of less than 200 meshes. The added dilute sulfuric acid is prepared with concentrated sulfuric acid, and the mass fraction of the dilute sulfuric acid is controlled to be 10% to 12%, and the volume mass ratio of the dilute sulfuric acid solution to the tantalum-niobium ore powder is (1.5 to 2.0): 1, and the dilute sulfuric acid solution is heated to 60°C, and then the tantalum-niobium ore powder is added until the temperature is heated to 85°C ± 5°C, the reaction time is 6h to 10h, and the residual acid content of the leaching solution after the reaction is completed is H2SO4: 45.00g / L to 55.00g / L.

[0031] Step 2, solid-liquid separation of the uranium, thorium and rare earth leaching solution to obtain a leaching solution clear solution and a filter cake, wherein the filter cake contains tantalum and niobium. Preferably, a chamber filter press is used to separate the leaching solution solid-liquid.

[0032] Step 3, adding sodium hydroxide solution to the clear solution of the leaching solution, and controlling the pH value to be 1.8-2.2, to obtain a uranium adsorption stock solution; wherein the mass fraction of the sodium hydroxide solution is 30%, and the contents of U in the uranium adsorption stock solution are: U: 0.80 g / L-2.20 g / L; ThO2: 0.40 g / L-3.70 g / L; RE2O3: 5.40 g / L-11.50 g / L; (Ta+Nb)2O5<0.50 g / L.

[0033] Step 4: Separate and extract uranium from the uranium adsorption stock solution using 201×7 strong alkaline anion exchange resin to obtain uranium saturated resin and adsorption tail liquid, wherein the uranium content in the adsorption tail liquid is controlled to be U≤5 mg / L.

[0034] Furthermore, the uranium saturated resin is eluted to obtain a qualified uranium eluted solution, which is a refined uranyl sulfate solution with a uranium content of 10.00 g / L to 40.00 g / L, and is precipitated with sodium hydroxide to obtain sodium diuranate; preferably, the uranium saturated resin is eluted with slightly acidic water. And 30% NaOH solution is added to the qualified uranium solution to control the pH value of the neutralized precipitated uranium to 6.8 to 7.2 to recover uranium, and the sodium diuranate product is obtained by filtering with a chamber filter press and washing the filter cake, and the product quality meets the standard requirements of "Technical Conditions for Diuranates" (EJ / T803-93).

[0035] Step 5, extracting the adsorption tail liquid to obtain a saturated organic phase and raffinate water; wherein the extractant in the extraction treatment is a primary amine, the extraction system is 5% primary amine + 5% mixed alcohol + 90% sulfonated kerosene, four-stage countercurrent extraction is used to extract and separate from the adsorption tail liquid, and the O / A ratio of the organic phase to the aqueous phase is 1 / 4, the mixed contact time is about 5 minutes, and the clarification time is about 10 minutes, to obtain a saturated organic phase, the thorium content of which is ThO2≥10.00g / L; the thorium raffinate water mainly contains rare earth sulfate, and the thorium content is ThO2<10mg / L, and the raffinate water is used for subsequent precipitation extraction of rare earth.

[0036] Step 6, stripping the saturated organic phase to obtain thorium carbonate water, and then precipitating with sulfuric acid to obtain thorium sulfate; wherein the stripping agent in the stripping treatment is 2mol / L (NH4)2CO3 solution, the organic phase and the aqueous phase have an O / A ratio of (25-35) / 1, the contact time is 5min, and the clarification time is 10min. The depleted product obtained by stripping can be returned to the thorium extraction process for recycling, and the thorium content in the depleted product is ThO2 <15mg / L.

[0037] Step 7, adding sodium carbonate solution to the raffinate water for neutralization and precipitation, filtering to obtain rare earth carbonate. Wherein, adding 20% ​​Na2CO3 solution to the raffinate water for precipitation and recovery of rare earth, and controlling the pH value of the neutralization precipitation to be 6.8-7.5.

[0038] The present invention is to add the associated tantalum-niobium ore to dilute sulfuric acid for leaching, control the leaching reaction conditions, obtain the leaching solution containing uranium, thorium and rare earth; adjust the acidity of the clear solution of the leaching solution to prepare the uranium adsorption stock solution, separate and extract uranium through 201×7 strong alkaline anion exchange resin, and recover uranium by precipitation; use primary amine extraction to separate and extract thorium from the uranium adsorption tail liquid, and recover thorium by acid precipitation; use sodium carbonate to precipitate and recover rare earth from the thorium extraction residual water. The whole process technology is reliable, easy to operate, and has low production cost, and the quality of the obtained sodium diuranate product meets the standard requirements of "Technical Conditions for Diuranate" (EJ / T803-93).

[0039] Furthermore, in step 2, the obtained filter cake can be subjected to multi-stage countercurrent washing to obtain the entrained leachate, and the washing water is incorporated into the leachate clear solution for preparing the uranium adsorption stock solution, thereby avoiding uranium loss and achieving the purpose of increasing the uranium content. Preferably, the filter cake is subjected to three-stage countercurrent washing to obtain a filter residue. The filter residue mainly contains tantalum and niobium metal oxides.

[0040] Further, in order to better illustrate the process and effect of a method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore, the following is described in detail through specific examples, the details are as follows:

[0041] Example 1

[0042] The associated tantalum-niobium ore components are (on a dry basis) Ta2O5: 20.47%, Nb2O5: 12.08%, U3O8: 3.20%, ThO2: 1.11%, RE2O3: 16.16%. It needs to be ground into ore powder with a particle size of less than -200 mesh.

[0043] A certain amount of concentrated sulfuric acid was added to the leaching tank, stirring was started, and a 11.80% H2SO4 solution was prepared. After heating to 60°C, the ground tantalum-niobium ore powder was added, and the liquid-to-solid mass ratio of the leaching reaction was controlled to be 1.5:1, the temperature was 87°C±2°C, the time was 10.0h, and the residual acid content of the leaching solution was H2SO4: 46.64g / L to obtain a leaching solution.

[0044] The leachate was subjected to solid-liquid separation by a chamber filter press, and the filter cake was subjected to three-stage countercurrent washing to obtain a filter residue, the components of which were (on a dry basis) Ta2O5: 22.68%, Nb2O5: 14.46%, U3O8: 0.08%, ThO2: 0.51%, and RE2O3: 3.47%;

[0045] The pH value of the combined solution of the leaching solution and the washing water was adjusted with 30% NaOH solution to prepare a uranium adsorption stock solution with the following contents: U: 1.58 g / L; ThO2: 0.78 g / L; RE2O3: 9.27 g / L; (Ta+Nb)2O5: 0.32 g / L, pH: 1.9.

[0046] 201×7 strong alkaline anion exchange resin was used to separate and extract uranium from the adsorption raw solution, and the adsorption tail liquid was used for subsequent extraction of thorium. The content of the adsorption tail liquid was U: 3.8 mg / L, ThO2: 0.78 g / L, and RE2O3: 9.27 g / L.

[0047] Using 0.01mol / L H2SO4 slightly acidic water as eluent, the saturated resin was desorbed to obtain a qualified uranium solution containing uranyl sulfate, with U: 32.68g / L in the qualified solution. 30% NaOH solution was added to the qualified solution to neutralize the precipitated uranium to a pH value of 7.2, and the sodium diuranate product composition (on a dry basis) was 52.67% U, SO4 2- : 1.82%, PO4 3- :0.12%, SiO2: 0.25%, F - :0.09%、Cl - : 0.06%.

[0048] The uranium adsorption tail liquid was subjected to four-stage countercurrent extraction to separate thorium using 5% primary amine + 5% mixed alcohol + 90% sulfonated kerosene organic phase. The organic phase and the aqueous phase had an O / A ratio of 1 / 4, a contact time of about 5 minutes, and a clarification time of about 10 minutes. The thorium content in the thorium raffinate water was ThO2: 8.1 mg / L, and the thorium content in the thorium saturated organic phase was ThO2: 15.36 g / L.

[0049] Thorium was extracted from the thorium-saturated organic phase by back extraction with 2 mol / L (NH4)2CO3 solution, using six-stage countercurrent back extraction, with the organic phase and aqueous phase ratio of O / A = 30 / 1, contact time of 5 minutes, and clarification time of 10 minutes. The thorium content in the depleted medium was ThO2: 13.0 mg / L.

[0050] Add 20% Na2CO3 solution to the raffinate water to precipitate and prepare rare earth carbonate, and recover rare earth. The precipitation pH is controlled to 7.2, and the prepared rare earth carbonate components are (on a dry basis) RE2O3: 80.91%, U: 2.64Bq / g.

[0051] Example 2

[0052] The associated tantalum-niobium ore components are (on a dry basis) Ta2O5: 36.57%, Nb2O5: 18.82%, U3O8: 2.16%, ThO2: 0.98%, RE2O3: 9.26%. It needs to be ground into ore powder with a particle size of <-200 mesh.

[0053] A certain amount of concentrated sulfuric acid was added to the leaching tank, stirring was started to prepare a 10.38% H2SO4 solution, and the ground tantalum-niobium ore powder was added after heating to 60°C. The liquid-to-solid mass ratio of the leaching reaction was controlled to be 1.7:1, the temperature was 85°C±2°C, the time was 8.0h, the residual acid content of the leaching solution was H2SO4: 53.28g / L, and a leaching solution was obtained.

[0054] The leachate was subjected to solid-liquid separation by a chamber filter press, and the filter cake was subjected to three-stage countercurrent washing to obtain a filter residue, the components of which were (on a dry basis) Ta2O5: 38.12%, Nb2O5: 20.98%, U3O8: 0.07%, ThO2: 0.64%, and RE2O3: 1.86%;

[0055] The pH value of the solution of the combined leaching solution and the washing water was adjusted with 30% NaOH solution to prepare a uranium adsorption stock solution, which contained U: 1.26 g / L; ThO2: 0.62 g / L; RE2O3: 8.20 g / L; (Ta+Nb)2O5: 0.39 g / L, and pH: 2.1.

[0056] 201×7 strong alkaline anion exchange resin was used to separate and extract uranium from the uranium adsorption stock solution. The adsorption tail liquid was used for subsequent extraction of thorium, and the components of the adsorption tail liquid were U: 4.2 mg / L, ThO2: 0.62 g / L, and RE2O3: 8.20 g / L.

[0057] Using 0.01 mol / L H2SO4 slightly acidic water as eluent, the saturated resin was desorbed to obtain a qualified uranium solution containing uranyl sulfate, with U: 28.12 g / L in the qualified solution. 30% NaOH solution was added to the qualified solution to neutralize the precipitated uranium to a pH of 6.9, and the sodium diuranate product composition (on a dry basis) was 58.40% U, SO4 2- :0.98%、PO4 3- :0.16%, S iO2: 1.36%, F - :0.08%、Cl - : 0.05%.

[0058] The obtained uranium adsorption tail liquid is subjected to four-stage countercurrent extraction to separate thorium using 5% primary amine + 5% mixed alcohol + 90% sulfonated kerosene. The organic phase and the aqueous phase have an O / A ratio of 1 / 4, a contact time of about 5 minutes, and a clarification time of about 10 minutes. The thorium content in the thorium raffinate water is ThO2: 7.9 mg / L, and the thorium content in the thorium-saturated organic phase is ThO2: 13.21 g / L.

[0059] Thorium was extracted from the thorium-saturated organic phase by back extraction with 2 mol / L (NH4)2CO3 solution, using six-stage countercurrent back extraction, with the organic phase and aqueous phase ratio of O / A = 28 / 1, contact time of 5 minutes, and clarification time of 10 minutes. The thorium content in the depleted medium was ThO2: 10.8 mg / L.

[0060] Add 20% Na2CO3 solution to the thorium extraction residual water to precipitate and prepare rare earth carbonate, recover the rare earth, control the precipitation pH to 7.0, and the prepared rare earth carbonate components are (on a dry basis) RE2O3: 78.98%, U: 3.54Bq / g.

[0061] Example 3

[0062] The associated tantalum-niobium ore components are (on a dry basis) Ta2O5: 26.40%, Nb2O5: 21.82%, U3O8: 0.32%, ThO2: 0.16%, and RE2O3: 20.96%.

[0063] A certain amount of concentrated sulfuric acid was added to the leaching tank, stirring was started to prepare a 10.86% H2SO4 solution, and the ground tantalum-niobium ore powder was added after heating to 60°C. The liquid-to-solid mass ratio of the leaching reaction was controlled to be 1.7:1, the temperature was 86°C±2°C, the time was 6.0h, the residual acid content of the leaching solution was H2SO4:51.61g / L, and a leaching solution was obtained.

[0064] The leachate is subjected to solid-liquid separation by a chamber filter press, and the filter cake is subjected to three-stage countercurrent washing to obtain a filter residue, the filter residue components of which are (on a dry basis) Ta2O5: 28.47%, Nb2O5: 33.19%, U3O8: 0.07%, ThO2: 0.08%, RE2O3: 4.57%;

[0065] The pH value of the combined solution of the leaching solution and the washing water was adjusted with 30% NaOH solution to prepare a uranium adsorption stock solution with the following contents: U: 0.98 g / L; ThO2: 0.40 g / L; RE2O3: 11.50 g / L; (Ta+Nb)2O5: 0.40 g / L, pH: 1.8.

[0066] 201×7 strong alkaline anion exchange resin was used to separate and extract uranium from the adsorption raw solution, and the adsorption tail liquid was used for subsequent extraction of thorium. The content of the adsorption tail liquid was U: 3.0 mg / L, ThO2: 0.40 g / L, and RE2O3: 11.50 g / L.

[0067] Using 0.01mol / L H2SO4 slightly acidic water as eluent, the saturated resin was desorbed to obtain a qualified uranium solution containing uranyl sulfate, and the U in the qualified solution was 16.50g / L. 30% NaOH solution was added to the qualified solution, and the pH value of the uranium recovered by neutralization precipitation was 7.2, and the components of the sodium diuranate product obtained were (on a dry basis) U: 52.67%, SO4 2- :1.75%、PO4 3- :0.08%, SiO2: 0.45%, F - :0.08%、Cl - : 0.05%.

[0068] The obtained uranium adsorption tail liquid is subjected to four-stage countercurrent extraction to separate thorium using 5% primary amine + 5% mixed alcohol + 90% sulfonated kerosene. The organic phase and the aqueous phase have an O / A ratio of 1 / 4, a contact time of about 5 minutes, and a clarification time of about 10 minutes. The thorium content in the thorium raffinate water is ThO2: 8.2 mg / L, and the thorium content in the thorium-saturated organic phase is ThO2: 10.06 g / L.

[0069] Thorium was extracted from the thorium-saturated organic phase by back extraction with 2 mol / L (NH4)2CO3 solution, using six-stage countercurrent back extraction, with the organic phase and aqueous phase ratio of O / A = 35 / 1, contact time of 5 minutes, and clarification time of 10 minutes. The thorium content in the depleted medium was ThO2: 10.5 mg / L.

[0070] Add 20% Na2CO3 solution to the raffinate water to precipitate and prepare rare earth carbonate, recover the rare earth, control the precipitation pH to 7.5, and the prepared rare earth carbonate components are (on a dry basis) RE2O3: 76.91%, U: 3.60Bq / g.

[0071] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0072] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0073] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore, characterized in that: The method comprises the following steps: Step 1, grinding the associated tantalum-niobium ore into tantalum-niobium ore powder of a preset particle size, and heating and reacting with a dilute sulfuric acid solution for a preset time to obtain a leaching solution containing uranium, thorium and rare earth, wherein the volume mass ratio of the dilute sulfuric acid solution to the tantalum-niobium ore powder is (1.5-2.0):1; Step 2, performing solid-liquid separation on the uranium, thorium and rare earth leaching solution to obtain a leaching solution clear liquid and a filter cake, wherein the filter cake contains tantalum and niobium; Step 3, adding sodium hydroxide solution to the clear solution of the leaching solution, and controlling the pH value to be 1.8-2.2, to obtain a uranium adsorption stock solution; Step 4, separating and extracting uranium from the uranium adsorption stock solution using 201×7 strong alkaline anion exchange resin to obtain uranium saturated resin and adsorption tail liquid, eluting the uranium saturated resin to obtain eluted uranium qualified liquid, and precipitating with sodium hydroxide to obtain sodium diuranate; Step 5, extracting the adsorption tail liquid to obtain a saturated organic phase and raffinate water; Step 6, stripping the saturated organic phase to obtain thorium carbonate water, and then precipitating with sulfuric acid to obtain thorium sulfate; Step 7, adding sodium carbonate solution to the raffinate water for neutralization and precipitation, and filtering to obtain rare earth carbonate.

2. The method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to claim 1, characterized in that: In step 2, the filter cake is subjected to multi-stage countercurrent washing to obtain the entrained leachate, and the washing water is incorporated into the leachate clear solution to prepare the uranium adsorption stock solution.

3. The method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to claim 1, characterized in that: In step 1, the particle size of the tantalum-niobium ore powder is less than 200 mesh.

4. The method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to claim 1, characterized in that: In step 1, the reaction temperature is 85°C ± 5°C, and the reaction time is 6h to 10h.

5. The method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to claim 1, characterized in that: In step 4, the uranium saturated resin is eluted with slightly acidic water.

6. The method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to claim 1, characterized in that: In step 5, the extractant is primary amine, the extraction system is 5% primary amine + 5% mixed alcohol + 90% sulfonated kerosene, and the O / A ratio of the organic phase to the aqueous phase is 1 / 4.

7. The method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to claim 1, characterized in that: In step 6, the stripping agent is 2 mol / L (NH4)2CO3 solution, and the O / A ratio between the organic phase and the aqueous phase is (25-35) / 1.

8. The method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to claim 1, characterized in that: In step 7, 20% Na2CO3 is added to the raffinate water, and the pH value of the neutralization precipitate is controlled to be 6.8-7.

5.

9. The method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to any one of claims 1 to 8, characterized in that: In step 1, the dilute sulfuric acid is prepared by using concentrated sulfuric acid to prepare a 10% to 12% H2SO4 solution.

10. The method for recovering uranium, thorium and rare earth from associated tantalum-niobium ore according to claim 9, characterized in that: In step 2, a chamber filter press is used to separate the solid and liquid of the leaching solution.

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