A synergistic extractant for acidic tungsten solutions and a method for the extraction separation of tungsten

Abstract

The application discloses a synergistic extractant of an acidic tungsten solution and a method for extracting and separating tungsten by using the same. The synergistic extractant of the acidic tungsten solution is composed of the following components: 20-30% of a phosphine amine composite extractant in volume; 0.5-1.0% of a pH responsive polyoxyethylene polyoxypropylene ether in mass; and the balance of a diluent. The phosphine amine composite extractant is a mixture of P227 and N235 in a volume ratio of 1.2-1.8:1. The pH responsive polyoxyethylene polyoxypropylene ether is a product obtained by grafting modification of a polyoxyethylene polyoxypropylene ether by using methyl acrylate as a functional monomer. The synergistic extractant of the acidic tungsten solution prepared by the application is suitable for deep extraction and purification of various kinds of acidic tungsten solutions, and has a remarkable improvement effect on problems such as low load capacity, slow mass transfer and large impurity interference in a traditional process.

Description

Technical Field

[0001] This invention belongs to the field of tungsten separation and purification technology in hydrometallurgy, and particularly relates to a synergistic extractant for acidic tungsten solution and a method for extracting and separating tungsten. Background Technology

[0002] Tungsten is a key strategic resource in national defense, military industry, and high-end manufacturing. Acidic extraction is a core process in tungsten smelting for separating and enriching tungsten from impurities. Existing technologies using commonly used extractants such as P204 and N235 have significant drawbacks, specifically: the loading capacity of a single extractant is limited (typically ≤8 g / L), requiring multiple extraction cycles; polytungstate has high mass transfer resistance, resulting in an extraction equilibrium time of 30-60 minutes; and impurities such as silicon and phosphorus compete with tungsten for extraction sites, leading to fluctuations in extraction rate and decreased product purity. Although some studies have attempted to improve performance through extractant blending, these efforts have largely focused on simple ratio adjustments and have not addressed the fundamental issues of extractant functional group synergy and interfacial mass transfer. Therefore, process innovation is urgently needed.

[0003] In summary, how to address the technical bottlenecks of traditional acidic tungsten extraction processes and provide a highly efficient acidic tungsten loading method with high loading capacity, fast mass transfer, and strong resistance to impurity interference, thereby achieving a dual improvement in the efficiency and purity of tungsten extraction, has become a pressing technical challenge. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a synergistic extractant for acidic tungsten solutions and a method for extracting and separating tungsten from them.

[0005] The objective of this invention is achieved through the following technical solution: A synergistic extractant for acidic tungsten solutions comprises the following components: by volume, 20-30% phosphonoamine composite extractant; by mass, 0.5-1.0% pH-responsive polyoxyethylene polyoxypropylene ether; and the remainder being a diluent. The phosphonoamine composite extractant is a mixture of P227 and N235 in a volume ratio of 1.2~1.8:1; The pH-responsive polyoxyethylene polyoxypropylene ether is a product obtained by grafting polyoxyethylene polyoxypropylene ether with methyl acrylate as a functional monomer.

[0006] Preferably, the diluent is sulfonated kerosene.

[0007] Preferably, the pH-responsive polyoxyethylene polyoxypropylene ether is prepared according to the following method: (1) Dissolve polyoxyethylene polyoxypropylene ether in anhydrous ethanol, add an initiator, then add methyl acrylate, and carry out the grafting reaction at 70~75℃ under a protective atmosphere. (2) After the grafting reaction is completed, the unreacted methyl acrylate and initiator are removed to obtain the crude product, which is then dried under vacuum to obtain the pH-responsive polyoxyethylene polyoxypropylene ether.

[0008] Preferably, the number average molecular weight of the polyoxyethylene polyoxypropylene ether in step (1) is 2000~3000, and the molar ratio of EO / PO is 3:1.

[0009] Preferably, the amount of initiator added in step (1) is 0.5 to 0.6 wt% of the polyoxyethylene polyoxypropylene ether.

[0010] Preferably, the initiator in step (1) is selected from azobisisobutyronitrile (AIBN).

[0011] Preferably, the amount of methyl acrylate added in step (1) accounts for 8 to 10 wt% of the polyoxyethylene polyoxypropylene ether.

[0012] Preferably, the protective atmosphere in step (1) is at least one of an inert gas or nitrogen.

[0013] Preferably, the grafting reaction in step (1) takes 4 to 6 hours.

[0014] Preferably, the specific steps for removing unreacted methyl acrylate and initiator in step (2) are as follows: add the product obtained after the reaction to petroleum ether, stir to allow the precipitate to fully separate, filter and collect the solid to obtain the crude product.

[0015] Preferably, the vacuum drying temperature in step (2) is 60~65℃ and the time is 7.5~8h.

[0016] A method for extracting and separating tungsten using the above-mentioned acidic tungsten solution as a synergistic extractant includes the following steps: S1. Take an acidic tungsten solution and adjust its pH to 1.0~2.8, add an impurity pre-complexing agent, and react at 30~45℃ under stirring conditions to obtain a pretreated acidic tungsten solution; The impurity complexing agent is a mixture of aminotrimethylphosphonic acid (ATMP) and sodium gluconate; The pre-complexing agent of ATMP and sodium gluconate can preferentially form stable complexes with silicon and phosphorus impurities, reducing their competitive adsorption on the extractant and ensuring the selectivity of tungsten extraction. S2. The synergistic extractant of the acidic tungsten solution and the pretreated acidic solution described in step S1 are mixed at a ratio of 1:1.5 to 3.0, and extracted at 35 to 50°C with stirring for 5 to 10 minutes. After extraction, the mixture is allowed to stand and separate to obtain the tungsten-loaded organic phase and the raffinate. In the synergistic extractant of the acidic tungsten solution, the phosphono group of P227 in the phosphonoamine composite extractant can achieve high-capacity binding of tungsten, and the amino functional group of N235 can enhance impurity repulsion. The synergistic effect of the two allows a single molecule of extractant to bind 3 to 4 tungsten ions, greatly improving the loading capacity. pH-responsive polyoxyethylene polyoxypropylene ether exhibits a high HLB value in acidic tungsten solution, significantly reducing the interfacial tension between the organic and aqueous phases, accelerating cross-phase mass transfer of tungsten species, and shortening the extraction equilibrium time to 5-10 min. The corresponding response mechanism is as follows: In acidic tungsten solution (pH=1.0~2.8), the carboxyl groups of pH-responsive polyoxyethylene polyoxypropylene ether are protonated, increasing molecular polarity and raising the HLB value (hydrophilic-lipophilic balance value) to 12~14, significantly reducing the interfacial tension between the organic phase (sulfonated kerosene + extractant) and the aqueous phase (from 35 mN / m to 8~10 mN / m); while in the back-extraction stage (dilute sulfuric acid / sodium hydroxide solution, pH=0.5~13), the carboxyl groups dissociate or react further, and the HLB value drops to 6~8, without affecting the back-extraction phase separation and avoiding emulsification problems.

[0017] S3. The tungsten-loaded organic phase described in step S2 is mixed with dilute sulfuric acid solution at a ratio of 1:1.5~3.0, and subjected to primary back-extraction at 40~55℃ under stirring for 15~25 minutes to obtain the organic phase after primary back-extraction and the waste liquid after primary back-extraction. S4. The organic phase after primary back-extraction described in step S3 is mixed with sodium hydroxide solution at a ratio of 1:1.1~2.0, and subjected to secondary back-extraction at 50~60℃ under stirring conditions for 20~35 minutes to obtain the organic phase after secondary back-extraction and high-purity tungsten back-extraction solution.

[0018] Preferably, the concentration of the acidic tungsten solution in step S1, calculated as WO3, is 2~16 g / L.

[0019] Preferably, the volume ratio of the acidic tungsten solution to the impurity complexing agent in step S1 is 10:0.8~1.

[0020] Preferably, the impurity pre-complexing agent in step S1 is prepared by the following method: aminotrimethylphosphonic acid and sodium gluconate are dissolved in water at a molar ratio of 1.25~1.67:1. After complete dissolution, a mixed solution with an aminotrimethylphosphonic acid concentration of 0.05~0.1mol / L and a sodium gluconate concentration of 0.03~0.08mol / L is obtained.

[0021] Preferably, the reaction time in step S1 is 15-30 min.

[0022] Preferably, the tungsten concentration in the raffinate in step S2 is ≤0.06 g / L.

[0023] Preferably, the concentration of the dilute sulfuric acid solution in step S3 is 5-8 wt%.

[0024] Preferably, the waste liquid after primary back-extraction in step S3 is recycled after resin adsorption, desorption, and regeneration.

[0025] Preferably, the concentration of the sodium hydroxide solution in step S4 is 12-18 wt%.

[0026] Preferably, the concentration of the high-purity tungsten back-extraction solution in step S4, calculated as WO3, is 40~65 g / L.

[0027] Preferably, the organic phase after secondary back-extraction in step S4 is recycled after regeneration treatment. The specific steps of the regeneration treatment are as follows: hydrochloric acid with a concentration of 0.5-1.0 mol / L is added to the organic phase after secondary back-extraction at a ratio of 1:1.0-2.0. After regeneration treatment for 10-20 min and phase separation, the organic phase is washed with water several times. The content of phosphine amine composite extractant and pH-responsive polyoxyethylene polyoxypropylene ether is detected and replenished, and recycled as a synergistic extractant for acidic tungsten solution to step S2.

[0028] Compared with the prior art, the beneficial effects of the present invention include: (1) The initial saturated loading capacity of the extractant described in this invention is 2.97~47.8 g / L. After the organic phase after secondary back-extraction is regenerated and recycled 15 times, the loading capacity can still be maintained at 50.5~66.11%, which is significantly improved compared with the loading capacity of existing single extractants (usually ≤8 g / L). Moreover, this invention can reduce the number of extraction stages and reduce equipment investment.

[0029] (2) The extraction equilibrium time of the present invention is shortened to 5-10 min, and the production efficiency is increased by 3-6 times compared with the prior art.

[0030] (3) Using the extraction method of the present invention, the tungsten extraction rate is ≥99.3%, the silicon and phosphorus removal rate is ≥97%, and the purity of the back-extraction solution is ≥99.7%. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] Example 1 (Medium tungsten concentration + medium impurity content) A synergistic extractant for acidic tungsten solutions comprises the following components: by volume, 25% phosphine-amine composite extractant; by mass, 0.7% pH-responsive polyoxyethylene-polyoxypropylene ether; and the balance being sulfonated kerosene. The phosphonoamine composite extractant is a mixture of P227 and N235 in a volume ratio of 1.5:1; The pH-responsive polyoxyethylene polyoxypropylene ether was prepared according to the following method: (1) Polyoxyethylene polyoxypropylene ether (number average molecular weight 2000~3000, EO / PO molar ratio 3:1) was dissolved in anhydrous ethanol, and 0.5 wt% of azobisisobutyronitrile was added, followed by 8 wt% of methyl acrylate. The grafting reaction was carried out at 70°C for 4 h under a nitrogen atmosphere. (2) After the grafting reaction is completed, the product obtained after the reaction is added to petroleum ether, stirred to allow the precipitate to be fully separated, filtered and collected to obtain the crude product. The crude product is vacuum dried at 60°C for 8 hours to obtain the pH-responsive polyoxyethylene polyoxypropylene ether.

[0033] A method for extracting and separating tungsten using the above-mentioned acidic tungsten solution as a synergistic extractant comprises the following steps: S1. Take 10L of acidic tungsten solution, with WO3 concentration of 10g / L, silicon concentration of 0.4g / L, and phosphorus concentration of 0.15g / L, and adjust its pH to 2.0; add 1L of impurity pre-complexing agent (an aqueous solution of a mixture of aminotrimethylphosphonic acid (ATMP) and sodium gluconate, with ATMP concentration of 0.08mol / L and sodium gluconate concentration of 0.05mol / L, and a molar ratio of 1.6:1), and react at 35℃ and stirring speed of 300r / min for 20min to complete the pre-complexing and fixation of silicon and phosphorus impurities, and obtain the pretreated acidic tungsten solution; S2. The synergistic extractant of the acidic tungsten solution and the pretreated acidic solution described in step S1 are mixed at a ratio of 1:2.5, and extracted at 40°C with stirring (450 r / min) for 8 min. After extraction, the mixture is allowed to stand for 20 min to separate the phases, resulting in a tungsten-loaded organic phase and a raffinate (the tungsten concentration in the raffinate is ≤0.04 g / L). S3. The tungsten-loaded organic phase described in step S2 is mixed with a 6 wt% dilute sulfuric acid solution at a ratio of 1:2.5, and subjected to a first-stage back-extraction treatment at 50°C with stirring for 20 min to remove the adsorbed silicon and phosphorus impurities in the organic phase, thereby obtaining the organic phase after first-stage back-extraction and the waste liquid after first-stage back-extraction. The waste liquid after primary back-extraction is recycled after resin adsorption, desorption, and regeneration. The specific operating steps are as follows: Resin adsorption: The waste liquid after primary back-extraction (containing silicon and phosphorus complexes, pH=1.0~2.0) is pumped into a D201 macroporous anion exchange resin column (column diameter:column height=1:8), and the flow rate is controlled at 2 BV / h (bed volume / hour). The resin has an adsorption rate of more than 95% for silicon-ATMP and phosphorus-ATMP complexes. The waste liquid after adsorption mainly contains sulfate ions, which are neutralized and then discharged. Eluent regeneration: A 2 mol / L sodium hydroxide solution (flow rate 1 BV / h) is passed into the resin column to elute the silicon-phosphorus complex, yielding an eluent (containing 0.03~0.05 mol / L ATMP and 0.02~0.03 mol / L sodium gluconate). Circulation preparation: ATMP and sodium gluconate are added to the eluent in proportion (to restore the concentration to 0.08mol / L and 0.05mol / L), which are directly used as the "impurity pre-complexing agent" in step S1, so as to realize the recycling of ATMP and sodium gluconate. The reagent loss rate can be reduced by 40%, and the amount of waste liquid discharged is reduced at the same time. S4. The organic phase after primary back-extraction described in step S3 is mixed with a 15wt% sodium hydroxide solution at a ratio of 1:1.5, and subjected to secondary back-extraction at 60°C under stirring for 30 minutes to obtain the organic phase after secondary back-extraction and a tungsten back-extraction solution with a concentration of 62g / L (tungsten purity of 99.8%). S5. Add 0.8 mol / L hydrochloric acid to the organic phase after the secondary back-extraction at a ratio of 1:1.5. After regeneration treatment for 15 min and phase separation, wash the organic phase with water three times. Detect and replenish the content of phosphine amine composite extractant (volume fraction to 25%) and pH-responsive polyoxyethylene polyoxypropylene ether (mass fraction to 0.7%) as synergistic extractants for acidic tungsten solution and recycle them to step S2.

[0034] Calculations showed that the initial saturated loading capacity of Example 1 should be 24.9 g / L, with an initial tungsten extraction rate of 99.5%, a silicon removal rate of 97.8%, and a phosphorus removal rate of 97.5%. After the organic phase following secondary back-extraction was regenerated and recycled 15 times, the loading capacity was 14.8 g / L, and the loading capacity retention rate was 65.46%. The initial saturated loading capacity refers to the maximum mass of tungsten (in WO3) that can be adsorbed per unit volume of the extracted organic phase. The calculation process is as follows: Formula: Loading capacity (g / L) = (Total initial tungsten in aqueous phase - Total tungsten in raffinate) ÷ Organic phase volume; Calculations corresponding to Example 1: Total initial WO3 in 10L aqueous phase = 10L × 10g / L = 100g, Total WO3 in raffinate = 10L × 0.04g / L = 0.4g, Organic phase volume = 4L (ratio 1:2.5), then Loading capacity = (100-0.4)g ÷ 4L = 24.9g / L.

[0035] Example 2 (High tungsten concentration + high impurity content) A synergistic extractant for acidic tungsten solutions comprises the following components: by volume, 30% is a phosphonoamine composite extractant; by mass, 1.0% is a pH-responsive polyoxyethylene polyoxypropylene ether; and the balance is sulfonated kerosene. The phosphonoamine composite extractant is a mixture of P227 and N235 in a volume ratio of 1.8:1; The pH-responsive polyoxyethylene polyoxypropylene ether was prepared according to the following method: (1) Polyoxyethylene polyoxypropylene ether (number average molecular weight 2000~3000, EO / PO molar ratio 3:1) was dissolved in anhydrous ethanol, and 0.5 wt% of azobisisobutyronitrile was added, followed by 8 wt% of methyl acrylate. The grafting reaction was carried out at 70°C for 4 h under a nitrogen atmosphere. (2) After the grafting reaction is completed, the product obtained after the reaction is added to petroleum ether, stirred to allow the precipitate to be fully separated, filtered and collected to obtain the crude product. The crude product is vacuum dried at 60°C for 8 hours to obtain the pH-responsive polyoxyethylene polyoxypropylene ether.

[0036] A method for extracting and separating tungsten using the above-mentioned acidic tungsten solution as a synergistic extractant comprises the following steps: S1. Take 10L of acidic tungsten solution, with WO3 concentration of 16g / L, silicon concentration of 0.7g / L, and phosphorus concentration of 0.3g / L, and adjust its pH to 2.8; add 0.8L of impurity pre-complexing agent (an aqueous solution of a mixture of aminotrimethylphosphonic acid (ATMP) and sodium gluconate, with ATMP concentration of 0.1mol / L and sodium gluconate concentration of 0.08mol / L, and a molar ratio of 1.25:1), and react at 45℃ and stirring speed of 400r / min for 30min to complete the pre-complexation and fixation of silicon and phosphorus impurities, and obtain the pretreated acidic tungsten solution; S2. The synergistic extractant of the acidic tungsten solution and the pretreated acidic solution described in step S1 are mixed at a ratio of 1:3.0, and extracted at 50°C with stirring (550 r / min) for 10 min. After extraction, the mixture is allowed to stand for 25 min to separate the phases, resulting in a tungsten-loaded organic phase and a raffinate (the tungsten concentration in the raffinate is ≤0.06 g / L). S3. The tungsten-loaded organic phase described in step S2 is mixed with a dilute sulfuric acid solution with a concentration of 8 wt% at a ratio of 1:3.0, and subjected to a first-stage back-extraction treatment at 55°C and under stirring conditions for 25 min to remove the adsorbed silicon and phosphorus impurities in the organic phase, thereby obtaining the organic phase after first-stage back-extraction and the waste liquid after first-stage back-extraction. The waste liquid after primary back-extraction is recycled after resin adsorption, desorption, and regeneration. The specific operating steps are as follows: Resin adsorption: The waste liquid after primary back-extraction (containing silicon and phosphorus complexes, pH=1.0~2.0) is pumped into a D201 macroporous anion exchange resin column (column diameter:column height=1:8), and the flow rate is controlled at 2 BV / h (bed volume / hour). The resin has an adsorption rate of more than 95% for silicon-ATMP and phosphorus-ATMP complexes. The waste liquid after adsorption mainly contains sulfate ions, which are neutralized and then discharged. Regeneration by elution: A 2 mol / L sodium hydroxide solution (flow rate of 1 BV / h) is passed into the resin column to elute the silicon-phosphorus complex and obtain the eluent. Circulation preparation: ATMP and sodium gluconate are added to the eluent in proportion (to restore the concentration to 0.1mol / L and 0.08mol / L), and used directly as the "impurity pre-complexing agent" in step S1 to realize the recycling of ATMP and sodium gluconate; S4. The organic phase after primary back-extraction described in step S3 is mixed with a sodium hydroxide solution with a concentration of 18 wt% at a ratio of 1:2.0, and subjected to secondary back-extraction at 65°C under stirring conditions for 35 min to obtain the organic phase after secondary back-extraction and a tungsten back-extraction solution with a concentration of 65 g / L (tungsten purity of 99.8%). S5. Add 1.0 mol / L hydrochloric acid to the organic phase after the secondary back-extraction at a ratio of 1:2.0. After regeneration treatment for 20 min and phase separation, wash the organic phase with water three times. Detect and replenish the content of phosphine-amine composite extractant (volume fraction to 30%) and pH-responsive polyoxyethylene polyoxypropylene ether (mass fraction to 1.0%) as synergistic extractants for acidic tungsten solution and recycle them to step S2.

[0037] Calculations show that the initial saturated loading capacity of Example 1 should be 47.8 g / L, the initial tungsten extraction rate is 99.3%, the silicon removal rate is 97.2%, and the phosphorus removal rate is 97.0%. After the organic phase after secondary back-extraction is regenerated and recycled 15 times, the loading capacity is 31.6 g / L, and the loading capacity retention rate is 66.11%.

[0038] Example 3 (Low tungsten concentration + low impurity content) A synergistic extractant for acidic tungsten solutions comprises the following components: by volume, 20% is a phosphonoamine composite extractant; by mass, 0.5% is a pH-responsive polyoxyethylene polyoxypropylene ether; and the balance is sulfonated kerosene. The phosphonoamine composite extractant is a mixture of P227 and N235 in a volume ratio of 1.2:1; The pH-responsive polyoxyethylene polyoxypropylene ether was prepared according to the following method: (1) Polyoxyethylene polyoxypropylene ether (number average molecular weight 2000~3000, EO / PO molar ratio 3:1) was dissolved in anhydrous ethanol, and 0.5 wt% of azobisisobutyronitrile was added, followed by 8 wt% of methyl acrylate. The grafting reaction was carried out at 70°C for 4 h under a nitrogen atmosphere. (2) After the grafting reaction is completed, the product obtained after the reaction is added to petroleum ether, stirred to allow the precipitate to be fully separated, filtered and collected to obtain the crude product. The crude product is vacuum dried at 60°C for 8 hours to obtain the pH-responsive polyoxyethylene polyoxypropylene ether.

[0039] A method for extracting and separating tungsten using the above-mentioned acidic tungsten solution as a synergistic extractant comprises the following steps: S1. Take 10L of acidic tungsten solution, with WO3 concentration of 2g / L, silicon concentration of 0.1g / L, and phosphorus concentration of 0.05g / L, and adjust its pH to 1.0; add 1L of impurity pre-complexing agent (an aqueous solution of a mixture of aminotrimethylphosphonic acid (ATMP) and sodium gluconate, with ATMP concentration of 0.05mol / L and sodium gluconate concentration of 0.03mol / L, and a molar ratio of 1.67:1), and react at 30℃ and stirring speed of 250r / min for 15min to complete the pre-complexing and fixation of silicon and phosphorus impurities, and obtain the pretreated acidic tungsten solution; S2. The synergistic extractant of the acidic tungsten solution and the pretreated acidic solution described in step S1 are mixed at a ratio of 1:1.5, and extracted at 35°C with stirring (300 r / min) for 5 min. After extraction, the mixture is allowed to stand for 15 min to separate the phases, resulting in a tungsten-loaded organic phase and a raffinate (the tungsten concentration in the raffinate is ≤0.02 g / L). S3. The tungsten-loaded organic phase described in step S2 is mixed with a 5 wt% dilute sulfuric acid solution at a ratio of 1:2.0, and subjected to a first-stage back-extraction treatment at 40°C with stirring for 15 min to remove the adsorbed silicon and phosphorus impurities in the organic phase, thereby obtaining the organic phase after first-stage back-extraction and the waste liquid after first-stage back-extraction. The waste liquid after primary back-extraction is recycled after resin adsorption, desorption, and regeneration. The specific operating steps are as follows: Resin adsorption: The waste liquid after primary back-extraction (containing silicon and phosphorus complexes, pH=1.0~2.0) is pumped into a D201 macroporous anion exchange resin column (column diameter:column height=1:8), and the flow rate is controlled at 2 BV / h (bed volume / hour). The resin has an adsorption rate of more than 95% for silicon-ATMP and phosphorus-ATMP complexes. The waste liquid after adsorption mainly contains sulfate ions, which are neutralized and then discharged. Regeneration by elution: A 2 mol / L sodium hydroxide solution (flow rate of 1 BV / h) is passed into the resin column to elute the silicon-phosphorus complex and obtain the eluent. Circulation preparation: ATMP and sodium gluconate are added to the eluent in proportion (to restore the concentration to 0.05mol / L and 0.03mol / L, respectively), and used directly as the "impurity pre-complexing agent" in step S1 to realize the recycling of ATMP and sodium gluconate; S4. The organic phase after primary back-extraction described in step S3 is mixed with a 12wt% sodium hydroxide solution at a ratio of 1:1.0, and subjected to secondary back-extraction at 50°C under stirring for 20 minutes to obtain the organic phase after secondary back-extraction and a tungsten back-extraction solution with a concentration of 40g / L (tungsten purity of 99.7%). S5. Add 0.5 mol / L hydrochloric acid to the organic phase after the secondary back-extraction at a ratio of 1:1.0. After regeneration treatment for 10 min and phase separation, wash the organic phase twice with water. Detect and replenish the contents of phosphine amine composite extractant (volume fraction to 20%) and pH-responsive polyoxyethylene polyoxypropylene ether (mass fraction to 0.5%) as synergistic extractants for acidic tungsten solution and recycle them to step S2.

[0040] Calculations show that the initial saturated loading capacity of Example 1 should be 2.97 g / L, the initial tungsten extraction rate is 99.8%, the silicon removal rate is 98.5%, and the phosphorus removal rate is 98.3%. After the organic phase after secondary back-extraction is regenerated and recycled 15 times, the loading capacity is 1.50 g / L, and the loading capacity retention rate is 50.5%.

[0041] Comparative Example 1 Compared with Example 1, the only difference is that pH-responsive polyoxyethylene polyoxypropylene ether is not added; all other operating steps, reagent dosages, and process parameters are completely consistent with Example 1.

[0042] Experimental results: The initial saturated loading capacity should be 18.47 g / L; the extraction equilibrium time was extended to 28 min (an increase of 250% compared to Example 1); the tungsten extraction rate decreased to 98.2% (a decrease of 1.3 percentage points), and the silicon and phosphorus removal rates decreased to 92.5% and 91.8% respectively (both decreased by more than 5 percentage points).

[0043] Conclusion: pH-responsive polyoxyethylene polyoxypropylene ether can significantly reduce the interfacial tension between the organic and aqueous phases, accelerate the mass transfer of tungsten species, and simultaneously improve the removal of impurities, which is key to improving loading capacity and extraction efficiency.

[0044] Comparative Example 2 Compared with Example 1, the only difference is that the "phosphonoamine complex extractant (P227+N235)" is replaced with "single P227 extractant", and the volume fraction of P227 in the organic phase is adjusted to 35% (to ensure that the total amount of extractant is equivalent to that in Example 1). All other operations are completely consistent with Example 1.

[0045] Experimental results: The initial saturated loading capacity should be 14.96 g / L; the tungsten extraction rate decreased to 96.7% (a decrease of 2.8 percentage points); the silicon and phosphorus removal rates decreased to 89.3% and 88.5% respectively (a decrease of more than 8 percentage points); the tungsten purity in the back-extraction solution was only 98.5% (99.8% in Example 1).

[0046] Conclusion: The synergistic effect of P227 and N235 can achieve both "high loading capacity" and "high selectivity" at the same time. A single extractant cannot achieve both. The dual-effect synergistic system is the core innovation of the process.

[0047] Comparative Example 3 Compared with Example 1, the only difference is that the acidic tungsten solution is not pretreated and is directly used for subsequent steps; all other operations are completely the same as in Example 1.

[0048] Experimental results: The initial saturated loading capacity should be 20.61 g / L; the tungsten extraction rate fluctuated to 97.1% (a decrease of 2.4 percentage points, and the extraction rate fluctuation range in parallel experiments reached ±1.5%); the accumulation of silicon and phosphorus impurities in the organic phase increased by 3 times compared with Example 1; the extractant showed a "poisoning" phenomenon after being recycled 5 times, and the loading capacity dropped to 14.34 g / L.

[0049] Conclusion: Impurity pre-complexing agents can fix silicon and phosphorus impurities in advance, avoiding their competition with tungsten for extraction sites and contamination of the extractant, which is the key to ensuring process stability and long extractant life.

[0050] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A synergistic extractant for acidic tungsten solutions, characterized in that, It consists of the following components: by volume, phosphine-amine composite extractant accounts for 20-30%; by mass, pH-responsive polyoxyethylene polyoxypropylene ether accounts for 0.5-1.0%; the balance is diluent; The phosphonoamine composite extractant is a mixture of P227 and N235 in a volume ratio of 1.2~1.8:1; The pH-responsive polyoxyethylene polyoxypropylene ether is a product obtained by grafting polyoxyethylene polyoxypropylene ether with methyl acrylate as a functional monomer.

2. The synergistic extractant for acidic tungsten solution according to claim 1, characterized in that, The diluent is sulfonated kerosene.

3. The synergistic extractant for acidic tungsten solution according to claim 1, characterized in that, The pH-responsive polyoxyethylene polyoxypropylene ether was prepared according to the following method: (1) Dissolve polyoxyethylene polyoxypropylene ether in anhydrous ethanol, add an initiator, then add methyl acrylate, and carry out the grafting reaction at 70~75℃ under a protective atmosphere. (2) After the grafting reaction is completed, the unreacted methyl acrylate and initiator are removed to obtain the crude product, which is then dried under vacuum to obtain the pH-responsive polyoxyethylene polyoxypropylene ether.

4. The synergistic extractant for acidic tungsten solution according to claim 3, characterized in that, The number-average molecular weight of the polyoxyethylene polyoxypropylene ether in step (1) is 2000~3000, and the molar ratio of EO / PO is 3:1; and / or The amount of initiator added in step (1) is 0.5~0.6 wt% of the polyoxyethylene polyoxypropylene ether; and / or The initiator in step (1) is selected from azobisisobutyronitrile; and / or In step (1), the amount of methyl acrylate added is 8-10 wt% of the polyoxyethylene polyoxypropylene ether; and / or The protective atmosphere in step (1) is at least one of an inert gas or nitrogen; and / or The grafting reaction in step (1) takes 4 to 6 hours.

5. The synergistic extractant for acidic tungsten solution according to claim 3, characterized in that, The specific steps for removing unreacted methyl acrylate and initiator in step (2) are as follows: add the product obtained after the reaction to petroleum ether, stir to allow the precipitate to fully separate, filter and collect the solid to obtain the crude product; and / or The vacuum drying temperature in step (2) is 60~65℃ and the time is 7.5~8h.

6. A method for extracting and separating tungsten using a synergistic extractant of the acidic tungsten solution according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Take an acidic tungsten solution and adjust its pH to 1.0~2.8, add an impurity pre-complexing agent, and react at 30~45℃ under stirring conditions to obtain a pretreated acidic tungsten solution; The impurity complexing agent is a mixture of aminotrimethylphosphonic acid and sodium gluconate; S2. The synergistic extractant of the acidic tungsten solution and the pretreated acidic solution described in step S1 are mixed at a ratio of 1:1.5 to 3.0, and extracted at 35 to 50°C with stirring for 5 to 10 minutes. After extraction, the mixture is allowed to stand and separate to obtain the tungsten-loaded organic phase and the raffinate. S3. The tungsten-loaded organic phase described in step S2 is mixed with dilute sulfuric acid solution at a ratio of 1:1.5~3.0, and subjected to primary back-extraction at 40~55℃ under stirring for 15~25 minutes to obtain the organic phase after primary back-extraction and the waste liquid after primary back-extraction. S4. The organic phase after primary back-extraction described in step S3 is mixed with sodium hydroxide solution at a ratio of 1:1.1~2.0, and subjected to secondary back-extraction at 50~60℃ under stirring conditions for 20~35 minutes to obtain the organic phase after secondary back-extraction and high-purity tungsten back-extraction solution.

7. The method for extracting and separating tungsten according to claim 6, characterized in that, The concentration of the acidic tungsten solution in step S1, calculated as WO3, is 2~16 g / L; and / or The reaction time in step S1 is 15-30 minutes.

8. The method for extracting and separating tungsten according to claim 6, characterized in that, The volume ratio of the acidic tungsten solution to the impurity complexing agent in step S1 is 10:0.8~1; and / or The impurity pre-complexing agent mentioned in step S1 is prepared by the following method: aminotrimethylphosphonic acid and sodium gluconate are dissolved in water at a molar ratio of 1.25~1.67:

1. After complete dissolution, a mixed solution with an aminotrimethylphosphonic acid concentration of 0.05~0.1mol / L and a sodium gluconate concentration of 0.03~0.08mol / L is obtained. and / or The tungsten concentration in the raffinate in step S2 is ≤0.06 g / L.

9. The method for extracting and separating tungsten according to claim 6, characterized in that, The waste liquid after primary back-extraction in step S3 is recycled after resin adsorption, desorption, and regeneration; and / or The concentration of the high-purity tungsten back-extraction solution in step S4, calculated as WO3, is 40~65 g / L.

10. The method for extracting and separating tungsten according to claim 6, characterized in that, The organic phase after secondary back-extraction in step S4 is recycled after regeneration treatment. The specific steps of the regeneration treatment are as follows: hydrochloric acid with a concentration of 0.5-1.0 mol / L is added to the organic phase after secondary back-extraction at a ratio of 1:1.0-2.

0. After regeneration treatment for 10-20 min and phase separation, the organic phase is washed with water several times. The content of phosphine amine composite extractant and pH-responsive polyoxyethylene polyoxypropylene ether is detected and replenished, and recycled as a synergistic extractant for acidic tungsten solution to step S2.