Method for purifying ammonium rhenate and ammonium rhenate

Abstract

The application provides a purification method of ammonium rhenate and ammonium rhenate, and belongs to the technical field of chemical industry. The purification method comprises the following steps: under a protective atmosphere, a complexing agent system is added to an ammonium rhenate solution to perform a complexing reaction; the material liquid after the complexing is subjected to ultrasonic treatment, and a scum generated after the ultrasonic treatment is separated to obtain a purified clear liquid; based on the metastable zone critical value control of a crystallization system, an anti-solvent is added to make ammonium rhenate crystals precipitate, and ammonium rhenate crystal slurry is obtained; the ammonium rhenate crystal slurry is subjected to solid-liquid separation, washing and drying to obtain high-purity ammonium rhenate. The application realizes efficient purification of crude ammonium rhenate, and the prepared refined ammonium rhenate has the advantages of high purity, low impurity content, good yield and the like, and can meet the demand of high-end fields for high-purity ammonium rhenate.

Description

Technical Field

[0001] This application relates to the field of chemical technology, and in particular to a method for purifying ammonium perrylate and the ammonium perrylate itself. Background Technology

[0002] Rhenium and its alloys possess unique properties, making them indispensable industrial raw materials for modern large-scale production. They are crucial raw materials in modern high-tech fields such as national defense, aerospace, electronics, and petrochemicals. When rhenium products are used as superalloying elements, chemical purity is the primary indicator of their quality. To meet the requirements for manufacturing ultra-high temperature alloys, the current domestic and international standards for rhenium particle chemical purity are ≥99.9%, which necessitates the use of raw materials with correspondingly higher purity. Ammonium perrhenate is an important intermediate in the preparation of other rhenium products; to obtain high-performance rhenium powder or rhenium products, high-purity ammonium perrhenate must be prepared.

[0003] Currently, the industrial purification of ammonium peroxide involves purifying the ammonium peroxide solution using appropriate methods, followed by crystallization to obtain high-purity ammonium peroxide. The main methods include chemical dissolution, extraction, recrystallization, and ion exchange. However, all of these methods have some drawbacks to varying degrees. For example, the washing process generates a large amount of alkaline wastewater, resulting in a heavy burden on wastewater treatment and making it unsuitable for large-scale industrial production. Furthermore, the addition of oxidants such as hydrogen peroxide is only effective in removing a few metallic impurities such as Fe and Cu, with weak removal effects on other metallic impurities.

[0004] Patent application CN202310350380.0 discloses a method for purifying crude ammonium perrhenate from copper smelting. The specific process is as follows: crude ammonium perrhenate is leached into a slurry to obtain leaching residue and leaching solution. Part of the leaching solution is returned to the acid adsorption process in an open circuit. The leaching residue obtained in the previous step is leached into a slurry and heated, followed by solid-liquid separation to obtain leaching residue and leaching solution. The leaching residue is returned to the system. The leaching solution from the previous step is oxidized by adding oxidant A and heated, followed by fine filtration. The oxidized residue is returned to the system. The oxidized solution is frozen and crystallized, followed by solid-liquid separation to obtain primary crystallization and post-primary crystallization solution. The primary crystallization is added to a solution and heated to dissolve. The filtrate is then crystallized under controlled temperature. The crystallized residue is separated and returned to dissolve. The post-primary crystallization solution is frozen and crystallized again, followed by filtration and washing to obtain secondary crystallization and post-secondary crystallization solution. The secondary crystallization solution is dried to obtain the final product, ammonium perrhenate.

[0005] Patent application CN202311392670.8 discloses a method for purifying ammonium permanganate. The method uses crude ammonium permanganate as raw material, and uses deionized water or distilled water, supplemented with oxidant and ammonia water, to dissolve it by heating. After ultrasonic activation, impurities are removed, and the solution is filtered to obtain ammonium permanganate solution. The solution is then cooled and crystallized, washed to remove soluble ions, and redissolved a second time to further remove impurity ions. After freeze crystallization, high-purity ammonium permanganate crystals are obtained by vacuum drying.

[0006] Since rhenium often coexists with molybdenum (Mo) and tungsten (W), its anions are similar in structure to those of high-rhenium anions. Traditional recrystallization methods have low separation coefficients, and improving purity often requires multiple recrystallizations, resulting in a significant decrease in rhenium recovery. On the other hand, pursuing high yields sacrifices purity. Summary of the Invention

[0007] This application is made in view of the above-mentioned problems, and its purpose is to provide a method for purifying ammonium perrylate and ammonium perrylate.

[0008] Specifically, the first aspect of this application provides a method for purifying ammonium perrylate, comprising the following steps: Crude ammonium perrylate was dissolved in water to obtain an ammonium perrylate solution containing impurities; Under a protective atmosphere, a complexing agent system is added to the ammonium perrylate solution to carry out a complexation reaction. The complexing agent system includes a thiol-containing complexing agent and a synergistic impurity remover. The complexed liquid is subjected to ultrasonic treatment and the scum is separated to obtain a purified clear liquid. The purified liquid was subjected to crystallization treatment, and an anti-solvent was added during the crystallization process to obtain ammonium perrylate slurry; The ammonium perrylate slurry was subjected to solid-liquid separation, washing, and drying to obtain high-purity ammonium perrylate.

[0009] Furthermore, the complexing agent system also includes polyaminocarboxylic acid complexing agents and antioxidants.

[0010] Furthermore, the protective atmosphere is an inert gas atmosphere; The antioxidant is ascorbic acid or its salt; The polyaminocarboxylic acid complexing agent is selected from at least one of ethylenediaminetetraacetic acid, cyclohexanediaminetetraacetic acid, or their soluble salts.

[0011] Furthermore, the thiol-containing complexing agent is selected from at least one of mercaptoethylamine, mercaptoethylamine salt, thioglycolic acid, or a salt thereof.

[0012] Furthermore, the synergistic impurity remover is mercapto-modified attapulgite.

[0013] Furthermore, the ultrasonic treatment involves intermittently ultrasonicating the complexed liquid at a frequency of 20-40 kHz for 15-60 minutes; after the ultrasonic treatment, the mixture is allowed to stand for 0.5-2 hours.

[0014] Furthermore, the initial dropping rate of the antisolvent addition is 0.5-0.8 mL / min, and the dropping rate is increased to 1.0-1.5 mL / min after crystal nuclei appear in the system.

[0015] Furthermore, the antisolvent is a mixture of C1-C4 lower alcohols and water, or a mixed solvent of two or more C1-C4 lower alcohols.

[0016] Furthermore, the antisolvent is preferably a mixture of ethanol and isopropanol, wherein the volume ratio of ethanol to isopropanol is 1-5:1.

[0017] Furthermore, the precipitation process of the ammonium perrylate crystals includes a programmed temperature control step, which includes: After antisolvent-induced nucleation, the temperature is first reduced from 44-46℃ to 23-26℃ at a rate of 1-3℃ / h. Then maintain the temperature at 23-26℃ for 6-10 hours; Finally, the temperature is reduced from 23-26℃ to 4-6℃ at a rate of 1-2℃ / h.

[0018] Further, the washing step includes: using a washing solution to prepare a slurry from the wet crystals of ammonium perrylate obtained from the initial solid-liquid separation, stirring and washing for 20-40 minutes under a heat preservation condition of 0-10°C, and then performing solid-liquid separation again; The washing solution is an aqueous solution of ethanol with a volume percentage of not less than 90% and a temperature of 0-10℃.

[0019] The second aspect of this application provides an ammonium perrylate, which is prepared by a purification method for said ammonium perrylate.

[0020] The present invention has the following beneficial effects: The ammonium perrye purification method provided by this invention utilizes a complexing agent system composed of a thiol complexing agent and a synergistic impurity remover. This system enables deep complexation and capture of various metallic impurities in the ammonium perrye solution. Combined with ultrasonic treatment, it promotes the aggregation of complexed impurities to form scum, facilitating separation and removal. This effectively solves the problems of narrow impurity removal range and poor impurity removal effect of traditional methods. Furthermore, this application precisely controls the antisolvent addition rate and the programmed cooling process during crystallization, regulating crystal growth based on the metastable region characteristics of the crystallization system. This avoids impurity encapsulation and co-crystallization, while ensuring high product purity and achieving a high rhenium yield. It balances product purity and yield, overcoming the limitation of traditional recrystallization methods that cannot simultaneously achieve both purity and yield. The ammonium perrye purified by this method has a low impurity content, and its purity meets the raw material requirements for high-purity ammonium perrye in high-end fields. Moreover, the process is simple and suitable for industrial-scale production. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following description and illustration are provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0022] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to the design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0023] The first aspect of this application provides a method for purifying ammonium perrylate, comprising the following steps: Crude ammonium perrylate was dissolved in water to obtain an ammonium perrylate solution containing impurities; Under a protective atmosphere, a complexing agent system is added to the ammonium perrylate solution to carry out a complexation reaction. The complexing agent system includes a thiol-containing complexing agent and a synergistic impurity remover. The complexed liquid is subjected to ultrasonic treatment, and the scum produced after ultrasonic treatment is separated to obtain purified clear liquid. The purified liquid is subjected to crystallization treatment. The addition of antisolvent is controlled based on the critical value of the metastable region of the crystallization system, so that ammonium perrylate crystals are precipitated to obtain ammonium perrylate slurry. The ammonium perrylate slurry was subjected to solid-liquid separation, washing, and drying to obtain high-purity ammonium perrylate.

[0024] In this embodiment, the complexing agent system further includes a polyaminocarboxylic acid complexing agent for complexing metal cation impurities, and an antioxidant for protecting the thiol-containing complexing agent from oxidation.

[0025] In this embodiment, the protective atmosphere is an inert gas protective atmosphere, such as a nitrogen atmosphere; the antioxidant is ascorbic acid or its salt; the polyaminocarboxylic acid complexing agent is selected from at least one of ethylenediaminetetraacetic acid (EDTA), cyclohexanediaminetetraacetic acid (CDTA), or their soluble salts; and the thiol-containing complexing agent is selected from at least one of mercaptoethylamine, mercaptoethylamine salt, thioglycolic acid, or their salts.

[0026] Specifically, under nitrogen protection, crude ammonium rheniumate is slowly added to deionized water, with stirring at 80-100 rpm, and the temperature raised to 50-60°C. The mixture is then kept at this temperature and stirred until completely dissolved. A polyaminocarboxylic acid complexing agent, such as EDTA-2Na, for complexing metal cation impurities is added to the ammonium rheniumate solution at a concentration of 0.5%-1.0% of the raw material mass. Simultaneously, 0.3%-0.6% of a thiol-containing complexing agent, such as mercaptoethylamine hydrochloride, and an antioxidant, such as ascorbic acid, are added.

[0027] The order of addition is as follows: first add EDTA-2Na and stir for 10 minutes; then add ascorbic acid; and finally slowly add mercaptoethylamine hydrochloride.

[0028] This application uses EDTA-2Na as a polyaminocarboxylic acid complexing agent, which can react with Fe in solution. 3+ Cu 2+ Ni 2+ This process allows metal cation impurities to form stable, soluble complexes, effectively reducing the risk of co-precipitation during subsequent crystallization. Mercaptoethylamine hydrochloride, as a mercapto-containing complexing agent, has a mercapto group (-SH) that can react with molybdate (MoO4) ions. 2- ), tungstate (WO4) 2- Impurity anions such as ) form complexes with specific structures. This complexation effect has high selectivity, especially for those with perrhenate (ReO4) - The presence of structurally similar impurities such as molybdenum and tungsten significantly enhances their separation from rhenium ions. The addition of ascorbic acid acts as an antioxidant, effectively protecting the thiol groups in mercaptoethylamine hydrochloride from oxidation by trace amounts of oxidizing substances in the solution or by oxygen in the air, thus ensuring its complexing activity against molybdenum and tungsten impurities.

[0029] The pH of the system is precisely controlled between 5.8 and 6.2 by adding dilute acid or alkali solutions dropwise. The complexation reaction time is usually controlled between 30 and 60 minutes to ensure that all impurities react fully with the complexing agent.

[0030] During the complexation reaction, ammonia (or dilute hydrochloric acid) is used to finely adjust the pH of the solution to 7-8.5. This pH range not only facilitates the formation of stable complexes between the complexing agent and various impurity ions, but also prevents ammonium rheniumate from decomposing or precipitating under excessively acidic or alkaline conditions, ensuring the dissolution rate of rhenium and the stability of the solution. The complexation reaction temperature is controlled at 50-60℃, the stirring rate is maintained at 150-200 rpm, and the reaction time is 40-60 minutes to ensure that impurities fully combine with the complexing agent to form stable complexes. Ammonium sulfate, a flocculant aid, is added to remove precipitates such as MoS3 and WS3.

[0031] The synergistic impurity removal agent is thiol-modified attapulgite. This material combines the physical adsorption properties of attapulgite with the chemical selectivity of its surface thiol groups, forming a micro-nano reaction system in solution. Through a synergistic mechanism of "adsorption enrichment-surface complexation," it significantly enhances the capture capacity for trace amounts of molybdenum, tungsten, and heavy metal ions. Simultaneously, this solid-phase medium is easily separated from the system, avoiding the influence of soluble complexing agent residues on subsequent crystallization. Combined with subsequent staged ultrasonic treatment (low-frequency cavitation exfoliation and high-frequency microbubble flotation), rapid phase transfer and separation of loaded impurities can be achieved, thereby simultaneously improving the product purity and metal recovery rate of ammonium rheniumate without the need for multiple recrystallizations.

[0032] The preparation method of mercapto-modified attapulgite is as follows: Take attapulgite (Lon brand attapulgite purchased from the market), stir and activate it with 5%-8% hydrochloric acid solution at 80-90℃ for 2-3 hours, wash it, and dry it at 105-110℃ for 4-6 hours to obtain acidified attapulgite.

[0033] Acidified attapulgite was added to an ethanol-water solution of 10%-15% by mass of 3-mercaptopropyltrimethoxysilane (ethanol to water volume ratio of 3:1), with a solid-liquid ratio of 1:10 (g / mL). The mixture was refluxed and stirred at 60-70℃ for 4-6 hours to achieve thiol functionalization modification.

[0034] After the reaction is complete, the mixture is washed and then vacuum dried at 80-90℃ for 6-8 hours to obtain mercapto-modified attapulgite.

[0035] During the complexation reaction stage, the amount added is 2%-5% of the mass of crude ammonium perrylate raw material. It is added after the addition of the mercapto complexing agent, and the reaction is continued to be stirred for 30-40 minutes to allow the modified attapulgite to fully adsorb and complex the impurities and micro-particles in the system.

[0036] In this embodiment, the ultrasonic treatment involves intermittently ultrasonicating the complexed liquid at a frequency of 20-40 kHz for 15-60 minutes; after ultrasonic treatment, the liquid is allowed to stand for 0.5-2 hours. Preferably, the complexed liquid is placed in a stirred tank equipped with a low-frequency ultrasonic transducer and subjected to intermittent ultrasonic treatment at a frequency of 28 kHz for 30 minutes, with the power density controlled at 0.3-0.5 W / cm³. 2 The low-frequency cavitation effect is used to break down agglomerates and promote adsorption. After ultrasonication, the mixture is allowed to stand for 1 hour, allowing the impurities to settle naturally due to the specific gravity of the modified attapulgite. The purified liquid is then separated by supernatant overflow or bottom filtration.

[0037] In this embodiment, the purified liquid is pumped into the crystallization vessel, and stirring is started at a speed of 40 rpm.

[0038] In this embodiment, the antisolvent is a mixture of C1-C4 lower alcohols and water, or a mixed solvent of two or more C1-C4 lower alcohols. The antisolvent is preferably a mixture of ethanol and isopropanol, wherein the volume ratio of ethanol to isopropanol is 1-5:1.

[0039] The specific operation of this step is as follows: The purified liquid is pumped into the crystallization vessel at a speed of 40 rpm. The antisolvent is a mixture of ethanol and isopropanol at a volume ratio of 7:3, with a total addition amount of 1.2-1.5 times the volume of the purified liquid. The antisolvent is added in stages at a preset rate: the initial dropping rate is controlled at 0.5-0.8 mL / min; after crystal nuclei appear, the dropping rate is increased to 1.0-1.5 mL / min to promote crystal growth. During the antisolvent addition process, the temperature control program is activated simultaneously, and the system is slowly reduced from 45℃ to 25℃ at a rate of 0.1-0.3℃ / h, and finally reduced to 5℃ to perfect the crystal lattice, ensuring slow crystal growth to obtain high purity.

[0040] In this embodiment, the precipitation process of the ammonium perrylate crystals includes a programmed temperature control step, which includes: After crystal growth is complete, resume stirring, reducing the speed to 20 rpm to prevent crystal breakage and promote mass transfer. Cool from 44-46℃ to 23-26℃ at a rate of 1-3℃ / h. Simultaneously, add the remaining antisolvent dropwise to the reactor at an extremely slow rate of 9-11 L / h. Ensure that the supersaturation is maintained at a low and stable level.

[0041] After the temperature drops to 23-26℃, stop cooling and maintain a constant temperature for 6-10 hours. During this stage, small crystals dissolve, and large crystals continue to grow.

[0042] After aging is complete, the cooling process is restarted, reducing the temperature from 23-26℃ to 4-6℃ at an extremely slow rate of 1-2℃ / h. Once the temperature reaches 4-6℃, the temperature is maintained at a constant level for 1-5 hours to ensure the crystallization process is completely finished.

[0043] In this embodiment, the washing step includes: using a pre-cooled washing liquid to prepare a slurry from the wet crystals of ammonium perrhenate obtained from the initial solid-liquid separation, stirring and washing for 20-40 minutes under a heat preservation condition of 0-10℃, and then performing solid-liquid separation again; placing the separated wet material in a vacuum oven at a temperature ≤ 60℃ and a vacuum degree ≤ -0.08 MPa, and drying it to constant weight to obtain high-purity ammonium perrhenate.

[0044] The second aspect of this application provides an ammonium perrylate, which is prepared by the purification method of the ammonium perrylate.

[0045] Example The following examples describe the disclosure of this invention in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight. Unless otherwise stated, all reagents used in the examples are available commercially or synthesized using conventional methods and are ready for use without further processing. Unless otherwise stated, all instruments used in the examples are available commercially.

[0046] The crude ammonium rhenium in the following examples were all taken from a comprehensive recovery workshop of a tungsten-molybdenum mine, with a purity of 98.2%. The main impurities were: Mo: 2350ppm, W: 920ppm, Fe: 180ppm, Cu: 65ppm, K: 210ppm, Na: 150ppm.

[0047] Example 1 A method for purifying ammonium perrylate includes the following steps: S1: Take 500g of crude ammonium rhenium sulfate, add 2L of deionized water to a 5L four-necked flask, purge with nitrogen gas (flow rate 0.5 L / min) and bubble for 30min, then heat to 55℃ to dissolve; pre-adjust the pH to 8.0 with ammonia water, add polyaminocarboxylic acid complexing agent (5g EDTA-2Na), mercapto-containing complexing agent (2g mercaptoethylamine), and antioxidant (0.2g ascorbic acid), and stir for 30min; add flocculant (1.5g ammonium sulfate), react at 55℃ for 1h, and collect the filtrate; Preparation of thiol-modified attapulgite: Attapulgite (commercially available Ron brand attapulgite) was activated by stirring at 85°C for 2 hours with a 6% hydrochloric acid solution. After washing, it was dried at 110°C for 5 hours to obtain acidified attapulgite. The acidified attapulgite was added to a 12% (w / w) aqueous solution of 3-mercaptopropyltrimethoxysilane in ethanol (ethanol to water volume ratio of 3:1), with a solid-liquid ratio of 1:10 (g / mL). The solution was refluxed and stirred at 60°C for 5 hours to achieve thiol functionalization modification. Adjust the pH of the filtrate to 2.5 with 2 mol / L dilute sulfuric acid, add 2g of mercapto-modified attapulgite, sonicate for 30 min, and filter to obtain purified liquid. S2: The purified liquid is subjected to intermittent ultrasonic treatment at a frequency of 30 kHz for 35 minutes, with a 5-minute working period followed by a 2-minute pause; after the ultrasonic treatment is completed, the liquid is allowed to stand for 1 hour to separate the scum and obtain the purified clear liquid. S3: The purified liquid is pumped into the crystallization vessel at a set speed of 40 rpm. The antisolvent is a mixture of ethanol and isopropanol at a volume ratio of 7:3, with a total addition amount of 1.3 times the volume of the purified liquid. The antisolvent is added in stages at a preset rate: the initial dropping rate is controlled at 0.6 mL / min; after reaching 38% of the total addition amount, the dropping rate is adjusted to 1.2 mL / min. During the antisolvent addition process, the system temperature is reduced from 45℃ to 25℃ at a rate of 2℃ / h, and maintained at this temperature for 8 hours. Finally, the temperature is reduced to 5℃ and maintained at this temperature for 1 hour. S4: Centrifuge the crystal slurry, transfer the filter cake to a washing tank, add 500 mL of 95% ethanol aqueous solution pre-cooled to 0℃, stir and wash for 30 minutes at 5℃, place the separated wet material in a vacuum oven at 55℃ and a vacuum of -0.08 MPa, and dry to constant weight to obtain ammonium rheniumate.

[0048] Example 2 This embodiment is basically the same as Embodiment 1, except that the amount of ascorbic acid added in step S1 is 0.15g.

[0049] Example 3 This embodiment is basically the same as embodiment 1, except that in step S2, the liquid is subjected to intermittent ultrasonic treatment at a frequency of 35kHz for 40 minutes, with a 1-minute pause every 3 minutes; after the ultrasonic treatment is completed, it is left to stand for 1 hour.

[0050] Example 4 This embodiment is basically the same as Embodiment 1, except that the antisolvent in step S3 is replaced with anhydrous ethanol (single solvent), while the dropping method remains unchanged.

[0051] Example 5 This embodiment is basically the same as Embodiment 1, except that the system temperature is slowly reduced from 45°C to 25°C at a rate of 2.5°C / h, held at that temperature for 6 hours, and finally reduced to 5°C for lattice improvement, held at that temperature for 1 hour.

[0052] Comparative Example 1 Take 500g of crude ammonium perrylate, add 2L of deionized water, heat to 80℃ to dissolve, cool naturally to room temperature (about 25℃), let stand to crystallize for 12h, filter, wash the filter cake with a small amount of cold water, and vacuum dry at 60℃.

[0053] Comparative Example 2 This comparative example is basically the same as Example 1, except that nitrogen protection is removed in step S1 (open system) and ascorbic acid is not added.

[0054] Comparative Example 3 This comparative example is basically the same as Example 1, except that the mercapto-modified attapulgite is replaced with ordinary attapulgite.

[0055] Comparative Example 4 This comparative example is basically the same as Example 1, except that mercapto-modified attapulgite is not added.

[0056] Comparative Example 5 This embodiment is basically the same as embodiment 1, except that the cooling procedure in step S3 is modified to: directly reduce the temperature from 45°C to 5°C at a constant rate of 5°C / h (without a constant temperature curing stage).

[0057] Experimental Case The purity of purified ammonium perrylate from Examples 1-5 and Comparative Examples 1-5 was determined using an inductively coupled plasma mass spectrometer (ICP-MS, Agilent 7900) with a detection limit of 0.1 ppb. The samples were dissolved in nitric acid before being tested. The results are shown in Table 1.

[0058]

[0059] As shown in Table 1, the ammonium permanganate purification method provided in this application, through the synergistic effect of multiple steps, can significantly reduce the content of major impurities in crude ammonium permanganate and greatly improve product purity. Compared with the traditional direct dissolution and cooling crystallization method (Comparative Example 1), the product purity of Examples 1-5 all reached 99.996% or higher, with Example 1 achieving a purity as high as 99.996%, and the impurity contents of Mo, W, and Fe as low as 3.2 ppm, 1.5 ppm, and 0.8 ppm, respectively, far superior to Comparative Example 1. Simultaneously, the method of this application, while ensuring high purity, also achieves a high product yield; the yield of Example 1 reached 96.8%, significantly higher than the 65.3% of Comparative Example 1.

[0060] Comparative Example 1 did not incorporate a synergistic complexation impurity removal system, so the impurities could not be removed through complexation-adsorption. It could only rely on the impurity separation effect of single crystallization. Therefore, the final product had a high impurity content and a purity of only 99.987%, which was lower than that of the embodiments in this application. This shows that the impurity removal system in this application has a good removal effect on the target impurities.

[0061] In Comparative Example 2, without nitrogen protection and without the addition of ascorbic acid, the thiol groups were easily oxidized and lost their complexing activity, failing to effectively bind impurity ions such as Mo and W. This resulted in a significant increase in the residual amount of Mo and W impurities in the final product, demonstrating that the combination of inert atmosphere protection and antioxidants can effectively maintain the complexing activity of thiol groups and ensure the impurity removal effect.

[0062] Comparative Example 3 used ordinary unmodified attapulgite, which relied solely on physical adsorption for impurity removal. Lacking the selective chemical complexation ability of thiol groups, its removal effect on Mo and W was far inferior to that of thiol-modified products. The final Mo residue reached 150 ppm, indicating that thiol modification is a key step in achieving deep impurity removal.

[0063] Comparative Example 4, without the addition of mercapto-modified attapulgite, relied solely on soluble complexing agents for complexation, which failed to achieve effective separation of impurity complexes. Some complexed impurities remained in the solution and were mixed into the product during final crystallization, leading to an increase in impurity content. This demonstrates that the synergistic mechanism of "complexation-adsorption-separation" can further enhance the impurity removal effect.

[0064] Comparative Example 5 eliminated the segmented temperature-controlled constant-temperature curing step and adopted rapid cooling for direct crystallization. The solution supersaturation fluctuated greatly, and a large number of impurities were encapsulated inside the crystal lattice during the crystallization process. The final product yield was reduced to 94.1%. This shows that the programmed temperature-controlled crystallization process of this application can maintain a stable supersaturation while ensuring the separation effect of impurities, thus taking into account both product purity and metal yield.

[0065] In summary, the ammonium perrhenate purification method of this application achieves efficient purification of crude ammonium perrhenate through the organic combination of steps such as complexation and protection during the dissolution stage, staged ultrasonic purification, programmed temperature control, and ultrasonic-assisted washing. The refined ammonium perrhenate prepared has the advantages of high purity, low impurity content, and good yield, which can meet the demand for high-purity ammonium perrhenate in high-end fields.

[0066] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for purifying ammonium perrylate, characterized in that, Includes the following steps: Crude ammonium perrylate was dissolved in water to obtain an ammonium perrylate solution containing impurities; Under a protective atmosphere, a complexing agent system is added to the ammonium perrylate solution to carry out a complexation reaction. The complexing agent system comprises a thiol-containing complexing agent, a synergistic impurity remover, a polyaminocarboxylic acid complexing agent, and an antioxidant. The antioxidant is ascorbic acid or a salt thereof. The polyaminocarboxylic acid complexing agent is selected from at least one of ethylenediaminetetraacetic acid, cyclohexanediaminetetraacetic acid, or a soluble salt thereof. The thiol complexing agent is selected from at least one of mercaptoethylamine, mercaptoethylamine salt, thioglycolic acid, or a salt thereof. The synergistic impurity remover is thiol-modified attapulgite. The complexed liquid is subjected to ultrasonic treatment and the scum is separated to obtain a purified clear liquid. The purified liquid is subjected to crystallization treatment, and an antisolvent is added during the crystallization process to obtain ammonium permanganate slurry; the antisolvent is a mixture of C1-C4 lower alcohols and water, or a mixed solvent of two or more C1-C4 lower alcohols; the initial dropping rate of the antisolvent is 0.5-0.8 mL / min, and the dropping rate is increased to 1.0-1.5 mL / min after crystal nuclei appear in the system; After antisolvent-induced nucleation, the temperature is first reduced from 44-46℃ to 23-26℃ at a rate of 1-3℃ / h. Then maintain the temperature at 23-26℃ for 6-10 hours; Finally, the temperature is reduced from 23-26℃ to 4-6℃ at a rate of 1-2℃ / h. The ammonium perrylate slurry was subjected to solid-liquid separation, washing, and drying to obtain high-purity ammonium perrylate.

2. The method for purifying ammonium perrylate according to claim 1, characterized in that, The ultrasonic treatment involves intermittently ultrasonicating the complexed liquid at a frequency of 20-40 kHz for 15-60 minutes; after the ultrasonic treatment, the mixture is allowed to stand for 0.5-2 hours.

3. The method for purifying ammonium perrylate according to claim 1, characterized in that, The antisolvent is a mixture of ethanol and isopropanol, wherein the volume ratio of ethanol to isopropanol is 1-5:

1.

4. The method for purifying ammonium perrylate according to claim 1, characterized in that, The washing step includes: using a washing solution to prepare a slurry from the wet crystals of ammonium perrylate obtained from the initial solid-liquid separation, stirring and washing for 20-40 minutes under a heat preservation condition of 0-10℃, and then performing solid-liquid separation again; The washing solution is an aqueous solution of ethanol with a volume percentage of not less than 90% and a temperature of 0-10℃.

5. An ammonium perrylate, characterized in that, It is prepared by the purification method of ammonium perrylate as described in any one of claims 1-4.

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