A process for the separation of rhenium from molybdenum concentrate leach solutions

Abstract

The present application relates to a method for separating rhenium from molybdenum concentrate leaching solution, belonging to the technical field of hydrometallurgy. The method comprises: obtaining acid sedimentation filtrate by ammonia pressure leaching and molybdenum acidification precipitation of low-grade molybdenum concentrate; using a mixture of Alamine 336 and D2EHPA as a synergistic extractant, and a hydrophobic ionic liquid as a diluent, extracting the acid sedimentation filtrate to obtain an organic phase containing molybdenum and rhenium; then using a stripping agent containing NH3H2O and H2O2, sequentially carrying out selective stripping of molybdenum and selective stripping of rhenium to obtain a molybdenum-containing stripping solution and a rhenium-rich solution, respectively. The present application replaces the traditional volatile organic diluent with an ionic liquid and constructs a synergistic extraction-stepwise stripping system, discarding the toxic thiocyanate and the strongly corrosive nitric acid, and realizing the efficient separation and enrichment of molybdenum and rhenium. The method is green and environmentally friendly, has high rhenium extraction rate and high product purity, and is especially suitable for the recovery of trace rhenium in low-grade molybdenum concentrate leaching solution.

Description

Technical Field

[0001] This invention relates to a method for separating rhenium from molybdenum concentrate leaching solution, belonging to the field of hydrometallurgical technology. Background Technology

[0002] Rhenium, as a scarce and dispersed strategic metal, possesses an ultra-high melting point, excellent high-temperature mechanical properties, and catalytic activity, making it irreplaceable in high-end fields such as aerospace high-temperature alloys, petrochemical catalysis, special metallurgy, and electronic new materials. Rhenium is extremely rare in the Earth's crust, with no independent exploitable deposits. It mainly occurs isomorphously in molybdenum concentrates, with low-grade molybdenum concentrates being a significant source of rhenium resources. Low-grade molybdenum concentrates generally have very low rhenium content, while also containing high levels of impurities such as iron and silicon. Achieving efficient separation of molybdenum and trace amounts of rhenium from its leachate, as well as the enrichment and recovery of rhenium, is of significant economic and strategic importance for improving the comprehensive utilization rate of rare and dispersed metal resources, revitalizing secondary mineral resources, and reducing resource waste.

[0003] Currently, common industrial processes for recovering rhenium from molybdenum concentrate leaching solutions include pyrometallurgical roasting enrichment, ion exchange, chemical precipitation, and traditional solvent extraction. Pyrometallurgical roasting easily generates large amounts of sulfur-containing flue gas, requiring significant investment in environmental protection and presenting high management challenges. Furthermore, some rhenium is converted into non-volatile rhenium salts during roasting, resulting in rhenium loss and a low overall rhenium recovery rate, making it difficult to meet the requirements for large-scale processing of low-grade molybdenum concentrate. Ion exchange processes require frequent adjustments to the solution's pH, consuming large quantities of reagents and generating significant amounts of process wastewater. The high cost of synthesizing specialized high-selectivity chelating resins further hinders their large-scale industrial application. Chemical precipitation processes easily lead to the co-precipitation of impurities such as arsenic and heavy metals with rhenium, resulting in low-grade rhenium-rich materials with high impurity content. Subsequent purification processes for high-purity rhenium products are lengthy, leading to poor overall production economics.

[0004] Solvent extraction, with its advantages of short process flow, high metal enrichment ratio, and ease of continuous automated production, has become the mainstream technology for the separation and recovery of molybdenum and rhenium in molybdenum concentrate leaching solutions in hydrometallurgy. However, existing traditional extraction processes still have many inherent defects. Traditional extraction systems mostly use volatile organic solvents such as kerosene and sulfonated kerosene as diluents, which easily generate volatile organic waste gases during operation. This not only poses safety hazards of flammability and explosion but also causes environmental pollution and ineffective solvent loss. The stability of organic phase recycling is also difficult to guarantee. Conventional extraction often uses single amine or phosphorus extractants, which cannot form an effective synergistic extraction effect and has limited co-extraction capacity for molybdenum and rhenium. Even when conventional organophosphorus reagents such as tributyl phosphate are used in combination with amine extractants, it is difficult to achieve ideal extraction results. The extraction efficiency of molybdenum and rhenium decreases significantly, and it is impossible to effectively capture trace amounts of rhenium in low-grade leaching solutions. Furthermore, the mutual entrainment of molybdenum and rhenium is serious, resulting in poor separation selectivity. While existing research has attempted to introduce ionic liquids to replace traditional organic diluents, most studies have opted for hydrophilic ionic liquids. These liquids have high solubility in aqueous phases, which easily leads to problems such as emulsification of the extraction system, interface blurring, and significantly prolonged phase separation time. Simultaneously, they cause continuous dissolution of organic phase components, resulting in rapid degradation of the extraction system structure and performance after repeated cycles, making it impossible to maintain continuous and stable operation in industrial production. In the back-extraction process, traditional processes commonly use reagents such as thiocyanate and concentrated nitric acid for molybdenum-rhenium back-extraction. Thiocyanate is highly toxic and carries a carcinogenic risk, while concentrated nitric acid is extremely corrosive and easily generates toxic nitrogen oxide gases during the reaction. This not only accelerates equipment corrosion and aging and increases operation, maintenance, and environmental treatment costs, but also easily introduces impurity ions into the solution system, severely reducing the purity of the rhenium-rich solution and making it difficult to prepare high-purity ammonium perrhenate products. In addition, existing conventional processes are difficult to achieve precise selective stepwise back-extraction of molybdenum and rhenium, and mostly adopt simultaneous back-extraction mode. The subsequent deep purification process is complicated, and the enrichment and recovery effect of trace rhenium in the leaching solution of low-grade molybdenum concentrate is not good. The comprehensive utilization rate of rhenium resources in minerals has always been low.

[0005] In summary, existing processes for separating and recovering rhenium from molybdenum concentrate leaching solutions generally suffer from insufficient environmental friendliness, low extraction and separation efficiency, poor molybdenum-rhenium selectivity, significant reagent toxicity and corrosiveness, weak organic phase circulation stability, and difficulty in adapting to the efficient recovery of trace rhenium from low-grade molybdenum concentrate. Developing a novel separation method that is environmentally friendly, achieves high molybdenum-rhenium extraction and separation purity, ensures a clean and pollution-free back-extraction process, allows for long-term stable recycling of the organic phase, and is suitable for the recovery of trace rhenium from low-grade molybdenum concentrate leaching solutions has become a pressing technical challenge in the field of hydrometallurgy. Summary of the Invention

[0006] The present invention aims to overcome the deficiencies of the prior art and provide a method for separating rhenium from molybdenum concentrate leaching solution, which is particularly suitable for the recovery of trace amounts of rhenium from low-grade molybdenum concentrate.

[0007] On one hand, the present invention relates to a method for separating rhenium from molybdenum concentrate leaching solution, comprising:

[0008] Molybdenum concentrate is subjected to ammonia pressure leaching to obtain molybdenum concentrate leaching solution, and the molybdenum concentrate leaching solution is acidified to precipitate molybdenum to obtain acid precipitation filtrate. The acid precipitation filtrate was extracted to obtain a molybdenum-rhenium-containing organic phase; The extractant used in the extraction process consists of Alamine 336 (trioctyl tertiary amine) and D2EHPA (di-2-ethylhexyl phosphoric acid), and the diluent is a hydrophobic ionic liquid. Selective back-extraction of molybdenum from the molybdenum-rhenium-containing organic phase yields a molybdenum-containing back-extraction solution and a rhenium-containing organic phase; Selective back-extraction of rhenium from the rhenium-containing organic phase yields a rhenium-containing back-extract. The stripping agents used for selective stripping of molybdenum and selective stripping of rhenium each independently contain NH3·H2O and H2O2.

[0009] Furthermore, in the method for separating rhenium from molybdenum concentrate leaching solution provided by the present invention, the extraction ratio O / A is 1:1 to 2:1, and the extraction method is 3 to 4 stages of countercurrent extraction.

[0010] Furthermore, in the method for separating rhenium from molybdenum concentrate leaching solution provided by the present invention, the ratio of O / A for selective back-extraction of molybdenum is 2:1 to 4:1, and the back-extraction method is 1 to 2 stages of countercurrent extraction.

[0011] Furthermore, in the method for separating rhenium from molybdenum concentrate leaching solution provided by the present invention, the ratio of O / A for selective back-extraction of rhenium is 1:1 to 1:2, the back-extraction method is 3 to 4 stages of countercurrent extraction, and the temperature is 35 to 40°C.

[0012] Generally, the parameters for any of the aforementioned countercurrent extractions are 10 min of mixing per stage followed by 15 min of settling.

[0013] Furthermore, in the method for separating rhenium from molybdenum concentrate leaching solution provided by the present invention, the molar ratio of Alamine 336 to D2EHPA is 1:1 to 2:1.

[0014] Furthermore, in the method for separating rhenium from molybdenum concentrate leaching solution provided by the present invention, the extracted organic phase, by volume percentage, consists of 10-20% of the extractant, 3-5% of long-chain alcohol, and the balance being the diluent.

[0015] Generally, the long-chain alcohol is a phase modifier, and the long-chain alcohol is isodecanol or n-octanol.

[0016] Furthermore, in the method for separating rhenium from molybdenum concentrate leaching solution provided by the present invention, the hydrophobic ionic liquid is [C8mim][NTf2] (1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt) or [C4mim][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate).

[0017] Furthermore, in the method for separating rhenium from molybdenum concentrate leaching solution provided by the present invention, the stripping agent for selectively stripping molybdenum contains 1.5~2.5 mol / L NH3·H2O, 0.15~0.30 mol / L H2O2, and the balance is water.

[0018] Furthermore, in the method for separating rhenium from molybdenum concentrate leaching solution provided by the present invention, the stripping agent in the selective stripping of rhenium contains 5.0~6.5 mol / L NH3·H2O, 0.15~0.30 mol / L H2O2, and the balance is water.

[0019] Furthermore, in the method for separating rhenium from molybdenum concentrate leaching solution provided by the present invention, the pH of the stripping agent in the selective stripping of rhenium is 11-12.

[0020] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages: This invention fundamentally eliminates VOC emissions during the extraction process by replacing traditional organic diluents with ionic liquids. Utilizing the synergistic effect of Alamine 336 and D2EHPA, one-step co-extraction of molybdenum and rhenium is achieved, significantly shortening the process. Simultaneously, using alkaline solutions of NH3·H2O / H2O2 at different concentrations as clean stripping agents avoids the introduction of toxic pollutants such as sulfur and nitrogen oxides. Stepwise selective stripping of molybdenum and rhenium completely eliminates toxic and harmful thiocyanates and highly corrosive nitric acid, making the entire separation process more environmentally friendly. Detailed Implementation

[0021] The technical solution of the present invention will be described below with reference to embodiments; however, the present invention is not limited to the following embodiments. Unless otherwise specified, the experimental and detection methods described in each embodiment are conventional methods; the reagents and materials described are commercially available unless otherwise specified. Unless otherwise specified, all percentages in the following embodiments refer to weight percentages. Unless otherwise specified, all ratios in the following embodiments refer to weight ratios. In the following embodiments, each experiment was repeated three times, and the average value of the experimental results was taken.

[0022] The low-grade molybdenum concentrate used in the following examples contains the following main chemical components by weight percentage: Mo 43.50%, Re 0.044% (440 g / t), Cu 0.85%, Ca 0.65%, P 0.09%, S 30.20%, Fe 5.80%, SiO2 16.40%, with the remainder being trace impurities such as Al, Mg, Mn, and As. This low-grade ore has a moderate molybdenum content, rhenium content within the typical low-grade resource range (0.03~0.05%), and relatively high levels of impurities such as iron and silicon.

[0023] Example 1 The synergistic extraction system used in this embodiment is Alamine 336+D2EHPA+[C8mim][NTf2], employing a medium ammonia immersion intensity and a three-stage extraction process.

[0024] (1) Ammonia pressure leaching Weigh out molybdenum concentrate and add ammonia solution at a slurry concentration of 180 g / L, along with 0.7 g NH3 / g ore. Place the solution in a high-pressure reactor. Start stirring at 450 rpm, introduce oxygen into the reactor to maintain an oxygen partial pressure of 1.2 MPa, raise the temperature to 140℃, and maintain the temperature and pressure for leaching for 150 min. After the reaction, cool to room temperature, filter, and obtain the molybdenum concentrate ammonia leaching solution. The concentrations of its main elements were measured as follows: Mo = 77.5 g / L (leaching rate approximately 99.0%), Re = 78 mg / L, and Cu = 1.51 g / L.

[0025] (2) Acidizing molybdenum precipitation Concentrated sulfuric acid was slowly added to the ammonia leaching solution with stirring to adjust the pH to 2.5. Stirring was continued for 30 minutes, followed by standing. The solution was then filtered to obtain ammonium molybdate crystals and an acid precipitation filtrate. The acid precipitation filtrate contained Mo = 1.04 g / L, Re = 78 mg / L, pH = 2.5, and redox potential ORP = +410 mV.

[0026] (3) Synergistic extraction of molybdenum and rhenium Organic phase preparation: By volume fraction, take 15% of the synergistic extractant (Alamine 336 and D2EHPA molar ratio 1.5:1), 4% of n-octanol, and the remainder is the hydrophobic ionic liquid [C8mim][NTf2], and stir until homogeneous.

[0027] Extraction procedure: Using the acid precipitate obtained in step (2) as the aqueous phase, the organic phase to aqueous phase volume ratio (O / A) was 1.5:1. A three-stage countercurrent extraction was performed at room temperature (25±2℃), with each stage mixing time of 10 min and a settling time of 15 min for phase separation. The organic phases were combined to obtain a molybdenum-rhenium-containing organic phase. Analysis of the aqueous raffinate showed that the Mo concentration decreased to <0.008 g / L and the Re concentration was <0.4 mg / L. Calculations showed that the rhenium extraction rate was approximately 99.5%, and the molybdenum extraction rate was approximately 99.2%.

[0028] (4) Selective back-extraction of molybdenum Preparation of the back-extraction agent: an aqueous solution containing 2.0 mol / L NH3·H2O and 0.20 mol / L H2O2.

[0029] Back-extraction operation: The supported organic phase was contacted with the above-mentioned back-extractant at a ratio of O / A = 3:1 for a first-stage countercurrent back-extraction. The mixture was stirred for 10 min, allowed to stand for 15 min at room temperature. After back-extraction, the Mo concentration in the aqueous phase (containing molybdenum back-extraction solution) was approximately 2.0 g / L, and the Re concentration was less than 0.5 mg / L. Molybdenum was essentially removed from the organic phase, and rhenium retention was ≥98.5%, yielding a rhenium-containing organic phase.

[0030] (5) Selective back-extraction of rhenium Preparation of the back-extraction agent: an aqueous solution containing 5.5 mol / L NH3·H2O and 0.20 mol / L H2O2, with a pH of 11.6.

[0031] Back-extraction operation: The rhenium-containing organic phase obtained in step (4) was contacted with the back-extractant at a ratio of O / A = 1:1.5 (organic phase volume: back-extractant volume = 1:1.5), and a three-stage countercurrent back-extraction was performed at 38°C, with each stage mixing for 10 min and standing for 15 min. The aqueous phases were combined to obtain a rhenium-rich solution, in which the Re concentration was approximately 35 mg / L and the Mo concentration was less than 10 mg / L. The rhenium back-extraction rate was 99.4%. After evaporation and concentration, the rhenium-rich solution was cooled and crystallized to obtain high-purity ammonium perrhenate crystals with a purity ≥99%. The organic phase could be reused in the extraction step after washing with water, and no performance degradation was observed after 20 cycles.

[0032] Example 2 This embodiment employs relatively mild ammonia leaching conditions and fewer extraction stages, while optimizing separation performance by using different ionic liquids [C4mim][PF6] and higher back-extraction.

[0033] (1) Ammonia pressure leaching The slurry was prepared with a slurry concentration of 120 g / L and an ammonia dosage of 0.5 g NH3 / g ore. It was stirred at 350 rpm in an autoclave, oxygen was introduced to maintain an oxygen partial pressure of 1.8 MPa, and the temperature was raised to 155℃. The reaction was carried out for 200 min. After cooling and filtration, the main components of the ammonia leaching solution were: Mo = 51.6 g / L (leaching rate approximately 98.9%), Re = 52 mg / L, and Cu = 1.00 g / L.

[0034] (2) Acidizing molybdenum precipitation The pH of the solution was adjusted to 2.2 with sulfuric acid, stirred, and then filtered to obtain the acid precipitate. The filtrate had a Mo concentration of 0.87 g / L, a Re concentration of 52 mg / L, a pH of 2.2, and an ORP of +425 mV.

[0035] (3) Synergistic extraction of molybdenum and rhenium Organic phase preparation: by volume percentage, the concentration of the co-extractant was 12% (Alamine 336:D2EHPA molar ratio 2:1), the phase modifier was 5% isodecanol, and the diluent was [C4mim][PF6].

[0036] Extraction procedure: A 4-stage countercurrent extraction was performed at room temperature (O / A = 1:1, mixing for 10 min per stage, followed by standing for 15 min). The raffinate contained Mo < 5 mg / L and Re < 0.2 mg / L. The rhenium extraction rate was approximately 99.6%, and the molybdenum extraction rate was approximately 99.4%.

[0037] (4) Selective back-extraction of molybdenum Back-extraction agent: NH3·H2O concentration 2.5mol / L, H2O2 concentration 0.30mol / L.

[0038] Back-extraction operation: Two-stage countercurrent back-extraction (room temperature) was performed at an O / A ratio of 4:1. The Mo concentration in the molybdenum-containing back-extraction solution was approximately 3.2 g / L, and Re < 0.6 mg / L; the rhenium retention rate in the organic phase was ≥ 99.0%.

[0039] (5) Selective back-extraction of rhenium Back-extraction agent: NH3·H2O concentration 6.0 mol / L, H2O2 concentration 0.30 mol / L, pH=11.9.

[0040] Back-extraction operation: Compared to O / A=1:1, a 4-stage countercurrent back-extraction was performed at 40℃. The resulting rhenium-rich solution had a Re concentration of approximately 52 mg / L and a Mo concentration below 8 mg / L. The rhenium back-extraction rate was 99.6%. This rhenium-rich solution was then evaporated and concentrated, followed by cooling and crystallization to obtain ammonium perrhenate product with a purity exceeding 99%. Furthermore, the organic phase showed stable phase separation time and extraction capacity after 25 cycles.

[0041] Example 3 This embodiment uses a higher extractant concentration, a lower back-extraction intensity, and a large phase ratio operation, which is suitable for different process conditions on site, and uses the same ionic liquid as in Example 1 but with a different ratio.

[0042] (1) Ammonia pressure leaching The pulp concentration was 200 g / L, the ammonia dosage was 0.6 g NH3 / g ore, the stirring speed was 500 r / min, the oxygen partial pressure was 1.0 MPa, the temperature was 130℃, and the leaching time was 220 min. The resulting ammonia leachate had the following properties: Mo = 85.8 g / L (leaching rate approximately 98.6%), Re = 86 mg / L, and Cu = 1.68 g / L.

[0043] (2) Acidizing molybdenum precipitation Adjust the pH to 3.0 with sulfuric acid, stir, and then filter. The concentration of Mo in the acid precipitation filtrate is 1.12 g / L, Re is 86 mg / L, pH is 3.0, and ORP is +390 mV.

[0044] (3) Synergistic extraction of molybdenum and rhenium Organic phase preparation: by volume, the concentration of the co-extractant was 18% (Alamine 336:D2EHPA molar ratio 1:1), the phase modifier was 3% n-octanol, and the diluent was [C8mim][NTf2].

[0045] Extraction procedure: A three-stage countercurrent extraction was performed at room temperature, with an O / A ratio of 2:1. The raffinate concentration of Mo was less than 10 mg / L, and the concentration of Re was less than 0.5 mg / L. The rhenium extraction rate was approximately 99.4%, and the molybdenum extraction rate was approximately 99.1%.

[0046] (4) Selective back-extraction of molybdenum Back-extraction agent: NH3·H2O concentration 1.5mol / L, H2O2 concentration 0.15mol / L.

[0047] Back-extraction operation: Perform stage 1 countercurrent back-extraction (room temperature) at a ratio of O / A = 4:1. The molybdenum-containing back-extraction solution has a Mo concentration of approximately 2.0 g / L and Re < 0.8 mg / L; the rhenium retention rate in the organic phase is ≥ 98.0%.

[0048] (5) Selective back-extraction of rhenium Back-extraction agent: NH3·H2O concentration 5.0 mol / L, H2O2 concentration 0.15 mol / L, pH=11.5.

[0049] Back-extraction operation: Compared to O / A = 1:1, a three-stage countercurrent back-extraction was performed at 35℃. The Re concentration in the rhenium-rich solution was approximately 43 mg / L (0.043 g / L), and the Mo concentration was less than 12 mg / L. The rhenium back-extraction rate was 99.1%. After evaporation and concentration, cooling and crystallization yielded ammonium perrhenate product with a purity of over 99%.

[0050] Comparative Example 1 The difference between this comparative example and Example 1 is that the organophosphate component in the synergistic extractant is replaced by TBP (tributyl phosphate) instead of D2EHPA, while the other conditions remain the same.

[0051] The molybdenum concentrate was subjected to pressure leaching with ammonia and acid precipitation to obtain an acid precipitation filtrate (same as in Example 1, Mo=1.04g / L, Re=78mg / L).

[0052] For organic phase preparation, 15% (by volume) of the co-extractant (with a molar ratio of Alamine 336 to TBP of 1.5:1), 4% n-octanol, and the remainder being a hydrophobic ionic liquid [C8mim][NTf2] were used. Three-stage countercurrent extraction was performed at room temperature with a phase ratio of O / A = 1.5:1, with each stage mixed for 10 min and allowed to stand for 15 min. Analysis of the raffinate after extraction revealed that the molybdenum concentration remained high at approximately 0.30 g / L, and the rhenium concentration was 12.8 mg / L. The molybdenum extraction rate was only 71.2%, and the rhenium extraction rate was only 83.6%.

[0053] Due to the significantly low organic phase loading, the subsequent back-extraction effect was greatly affected. After selective back-extraction of molybdenum, the molybdenum concentration in the molybdenum-containing back-extraction solution was only about 0.85 g / L, while the rhenium concentration was as high as about 23 mg / L, with a rhenium retention rate of about 82% in the organic phase. Finally, the rhenium-rich solution obtained from rhenium back-extraction had a rhenium concentration of only about 21 mg / L, while the molybdenum entrainment was as high as about 55 mg / L, making it impossible to obtain a high-purity rhenium product.

[0054] Comparative Example 2 The only difference between this comparative example and Example 1 is that the diluent is replaced by the hydrophobic ionic liquid [C8mim][NTf2] with the hydrophilic ionic liquid [BMIM]BF4 (1-butyl-3-methylimidazolium tetrafluoroborate), while all other conditions remain the same.

[0055] The pretreatment steps were the same as in Example 1, resulting in an acid precipitation filtrate. The filtrate was prepared using an organic phase containing 15% (v / v) of synergistic extractant (Alamine 336:D2EHPA molar ratio 1.5:1), 4% n-octanol, and the balance [BMIM]BF4.

[0056] Extraction conditions remained unchanged: O / A = 1.5:1, room temperature, 3-stage countercurrent extraction. However, in actual operation, due to the strong hydrophilicity of [BMIM]BF4, severe emulsification and three-phase phenomena occurred in the first stage, forcing the phase separation time to be extended to over 40 minutes, and the phase interface remained unclear. After combining the raffinates from each stage, severe emulsification made it impossible to obtain a homogeneous and representative sample for accurate analysis; simultaneously, the volume of the organic phase decreased significantly after each extraction stage, indicating that the ionic liquid continuously dissolved into the aqueous phase. After three cycles, the organic phase almost completely lost its phase separation ability, and the extraction performance declined to less than 30% of its initial value. The entire extraction system could not operate stably, and subsequent back-extraction was impossible, rendering it unsuitable for industrial application.

[0057] As described above, the basic principles, main features, and advantages of the present invention have been well described. The above embodiments and specifications are merely descriptions of preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. Various changes and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit and scope of the present invention should fall within the protection scope defined by the present invention.

Claims

1. A method for separating rhenium from molybdenum concentrate leaching solution, characterized in that, include: Molybdenum concentrate is subjected to ammonia pressure leaching to obtain molybdenum concentrate leaching solution, and the molybdenum concentrate leaching solution is acidified to precipitate molybdenum to obtain acid precipitation filtrate. The acid precipitation filtrate was extracted to obtain a molybdenum-rhenium-containing organic phase; The extractant used in the extraction process consists of Alamine 336 and D2EHPA, and the diluent is a hydrophobic ionic liquid. Selective back-extraction of molybdenum from the molybdenum-rhenium-containing organic phase yields a molybdenum-containing back-extraction solution and a rhenium-containing organic phase; Selective back-extraction of rhenium from the rhenium-containing organic phase yields a rhenium-containing back-extract. The stripping agents used for selective stripping of molybdenum and selective stripping of rhenium each independently contain NH3·H2O and H2O2.

2. The method for separating rhenium from molybdenum concentrate leaching solution according to claim 1, characterized in that, The extraction ratio O / A is 1:1 to 2:1, and the extraction method is 3 to 4 stages of countercurrent extraction.

3. The method for separating rhenium from molybdenum concentrate leaching solution according to claim 1, characterized in that, The selective back-extraction of molybdenum has an O / A ratio of 2:1 to 4:1, and the back-extraction method is 1 to 2 stages of countercurrent extraction.

4. The method for separating rhenium from molybdenum concentrate leaching solution according to claim 1, characterized in that, The selective back-extraction of rhenium has an O / A ratio of 1:1 to 1:2, and the back-extraction method is 3 to 4 stages of countercurrent extraction at a temperature of 35 to 40°C.

5. The method for separating rhenium from molybdenum concentrate leaching solution according to claim 1, characterized in that, The molar ratio of Alamine336 to D2EHPA is 1:1 to 2:

1.

6. The method for separating rhenium from molybdenum concentrate leaching solution according to claim 5, characterized in that, The extracted organic phase, by volume percentage, consists of 10-20% of the extractant, 3-5% of long-chain alcohols, and the balance being the diluent.

7. The method for separating rhenium from molybdenum concentrate leaching solution according to claim 1, characterized in that, The hydrophobic ionic liquid is [C8mim][NTf2] or [C4mim][PF6].

8. The method for separating rhenium from molybdenum concentrate leaching solution according to claim 1, characterized in that, The selectively stripped molybdenum stripping agent contains 1.5~2.5 mol / L NH3·H2O, 0.15~0.30 mol / L H2O2, and the balance is water.

9. The method for separating rhenium from molybdenum concentrate leaching solution according to claim 1, characterized in that, The selectively back-extracting rhenium contains 5.0-6.5 mol / L NH3·H2O, 0.15-0.30 mol / L H2O2, and the balance is water.

10. The method for separating rhenium from molybdenum concentrate leaching solution according to claim 9, characterized in that, The pH of the stripping agent in the selectively stripped rhenium is 11-12.