A method for recovering tungsten and rhenium from tungsten-rhenium alloy scrap

Abstract

This invention provides a method for recovering tungsten and rhenium from tungsten-rhenium alloy waste, comprising the following steps: S1. Collecting tungsten-rhenium alloy waste, crushing it to obtain tungsten-rhenium alloy waste powder; S2. Placing the cleaned tungsten-rhenium alloy waste powder into a reactor, and then adding a strongly alkaline solution containing hydrogen peroxide to it for reaction; in the strongly alkaline solution, the OH- ions dissociated by the strongly alkaline substance... ‑ The concentration of hydrogen peroxide was 2.0–4.0 mol / L, and the mass fraction of hydrogen peroxide in the strongly alkaline solution was 5–15%. During the reaction, oxidizing gas was continuously introduced into the reactor simultaneously, and ultrasonic treatment was applied. After the reaction, solid-liquid separation was performed, and the leachate was collected. Then, the tungsten-containing and rhenium-containing ions in the leachate were separated to obtain tungsten-containing and rhenium-containing solutions, respectively. These solutions were then further processed to obtain tungsten salts or metallic tungsten, and rhenium salts or metallic rhenium. This method effectively overcomes the passivation problem and improves the leaching rate and recovery rate of W and Re.

Description

Technical Field

[0001] This invention belongs to the field of rare metal hydrometallurgy and secondary resource recycling technology, specifically relating to a method for recovering tungsten and rhenium from tungsten-rhenium alloy waste. Background Technology

[0002] Tungsten-rhenium (W-Re) alloys, especially binary W-Re alloys, have important applications in cutting-edge fields such as high-temperature temperature measurement and the electronics industry due to their extremely high melting point, excellent high-temperature strength, and good plasticity. Waste W-Re alloys contain high concentrations of the strategic metal tungsten and the extremely rare metal rhenium, making them a valuable secondary resource for recycling.

[0003] Currently, the technology for recovering W-Re alloys, such as W-Re binary alloys, faces significant bottlenecks. Both tungsten and rhenium are chemically very stable metals, making them extremely difficult to dissolve with conventional acids. Existing technologies often employ high-temperature pyrometallurgical oxidation, such as oxygen roasting at temperatures above 800°C, utilizing the volatile nature of rhenium oxides for separation. However, this method is extremely energy-intensive, requires substantial equipment investment, and easily generates dust pollution. In wet processes, acid leaching faces a severe passivation problem; after tungsten is oxidized, a dense, acid-insoluble tungstic acid (H₂WO₄) protective layer forms on the alloy surface, rapidly terminating the reaction and resulting in extremely low leaching rates and incomplete reaction. Therefore, developing a technology that can effectively overcome the passivation problem under mild conditions and achieve efficient and complete leaching and separation of W and Re is a pressing technical challenge in this field. Summary of the Invention

[0004] The purpose of this invention is to solve one of the problems existing in the prior art, such as high energy consumption, severe passivation, and low leaching efficiency.

[0005] This invention provides a method for recovering tungsten and rhenium from tungsten-rhenium alloy waste, comprising the following steps: S1. Collecting tungsten-rhenium alloy waste, crushing it to obtain tungsten-rhenium alloy waste powder; S2. Placing the cleaned tungsten-rhenium alloy waste powder into a reactor, and then adding a strongly alkaline solution containing hydrogen peroxide to it for reaction; in the strongly alkaline solution, the OH- ions dissociated by the strongly alkaline substance... - The concentration of hydrogen peroxide is 2.0~4.0 mol / L, and the mass fraction of hydrogen peroxide in the strongly alkaline solution is 5~15%. During the reaction, oxidizing gas is continuously introduced into the reactor and ultrasonic treatment is applied simultaneously. S3. After the reaction is completed, solid and liquid are separated, the leachate is collected, and then the tungsten-containing ions and rhenium-containing ions in the leachate are separated to obtain tungsten-containing ion solutions and rhenium-containing ion solutions, respectively. After subsequent processing, tungsten salt or metallic tungsten and rhenium salt or metallic rhenium are obtained.

[0006] First, the collected tungsten-rhenium alloy waste is crushed, which can significantly increase the specific surface area and provide a sufficient reaction interface for the subsequent liquid-solid reaction, thereby shortening the leaching time and increasing the leaching rate.

[0007] Secondly, and most importantly, this invention utilizes a specific strongly alkaline hydrogen peroxide synergistic oxidation system to oxidize tungsten-rhenium alloy waste powder. Firstly, under strongly alkaline conditions, hydrogen peroxide is more effective at oxidizing low-valence tungsten and rhenium in the alloy to high-valence states (e.g., oxidizing W from a low valence state to WO4). 2- Re is oxidized from a lower oxidation state to ReO4 - Firstly, the strong alkaline conditions promote rapid dissolution, increasing the leaching rate of tungsten and rhenium, and thus improving their subsequent recovery rate. Secondly, the strong alkaline conditions ensure that tungsten, after oxidation, immediately generates soluble sodium tungstate (Na2WO4), completely avoiding the formation of a sparingly soluble tungstic acid passivation layer under acidic or neutral conditions, thus guaranteeing efficient leaching of tungsten and rhenium. Furthermore, controlling the concentration of OH- ions dissociated from the strong alkaline substances in the solution to 2.0–4.0 mol / L and the mass fraction of hydrogen peroxide to 5–15% facilitates the synergistic effect of both, ensuring efficient and high-recovery rates of tungsten and rhenium, as well as the safety of the reaction process. If the concentration of OH- ions dissociated from the strong alkaline substances is too low, it cannot effectively destroy the passivation layer of tungsten, leading to insufficient dissolution efficiency of tungsten and rhenium and the easy precipitation of sparingly soluble substances such as tungstic acid. If the concentration of OH- ions dissociated from a strongly alkaline substance is too high, the decomposition rate of H2O2 will be too fast (exponentially increasing), causing a sharp drop in its utilization rate as an oxidant, which is also detrimental to the full and efficient dissolution of tungsten and rhenium. Similarly, if the mass fraction of hydrogen peroxide is too low, the oxidizing kinetics for rhenium and tungsten will be insufficient, which is not conducive to the full dissolution of tungsten and rhenium and reduces the recovery rate; while if the mass fraction of hydrogen peroxide is too high, it will decompose faster under alkaline conditions, resulting in waste, and the decomposition will produce a large number of bubbles, which will disrupt the normal reaction; at the same time, the decomposition will cause local overheating, disrupt the reaction temperature window, and easily cause excessive dissolution of impurities.

[0008] Furthermore, oxidizing gases are simultaneously introduced during the above reaction process, forming a "liquid-gas dual oxidation" system. This facilitates efficient leaching at lower temperatures and normal pressures. Moreover, the oxidizing gas not only replenishes oxidation capacity, reducing H2O2 decomposition losses and total consumption, but its rising and breaking process also generates strong microscopic disturbances, further enhancing mass transfer and increasing the dissolution rates of tungsten and rhenium. Simultaneously, it avoids the co-dissolution of impurities caused by localized over-alkali treatment, improving the leaching selectivity of tungsten and rhenium. In addition, ultrasonic treatment is applied during the reaction process. The cavitation effect of ultrasound greatly accelerates the mass transfer between H2O2 and the alloy surface and can promptly remove any potentially attached localized products, ensuring continuous renewal of the reaction interface, thereby increasing the leaching rates of tungsten and rhenium and ultimately improving their recovery rates.

[0009] Therefore, under the synergistic effect of a strongly alkaline hydrogen peroxide-assisted oxidation system, oxidizing gas, and ultrasonic treatment, the leaching rate of tungsten-rhenium alloy waste can be further improved, thereby increasing the final recovery rate of tungsten and rhenium.

[0010] Preferably, in step S1, the collected tungsten-rhenium alloy waste is subjected to hydrogen embrittlement treatment before being crushed. Preferably, the hydrogen embrittlement treatment specifically involves calcining the tungsten-rhenium alloy waste at 800-1100°C for 1-3 hours, while introducing a hydrogen atmosphere at a flow rate of 200-500 mL / min. Preferably, the crushing method includes at least one of ball milling and hammer milling. After hydrogen embrittlement treatment, hydrogen atoms penetrate the alloy lattice, significantly reducing its toughness and making it brittle. After cooling, the hydrogen-embrittled alloy is easily crushed mechanically (e.g., by ball milling or hammer milling) to obtain irregular particle powder with a small particle size range.

[0011] Preferably, in step S1, the particle size of the tungsten-rhenium alloy waste powder is 0.1~1.0 mm. Preferably, after crushing, the tungsten-rhenium alloy waste powder with a particle size of 0.1~1.0 mm is obtained by sieving. Preferably, sieving is performed using a multi-stage vibrating screen. Selecting tungsten-rhenium alloy waste powder within the above particle size range for the reaction ensures that the powder has sufficient specific surface area, optimizes the reaction rate, shortens the leaching time, and improves the leaching rate of tungsten and rhenium. It also ensures uniform particle dispersion during the reaction, avoiding excessively high or low local concentrations, thereby improving reaction uniformity, mass transfer efficiency, and optimizing the leaching effect of tungsten and rhenium. If the particle size is too large, it may lead to uneven reaction and incomplete reaction of some particles; if the particle size is too small, it may lead to particle agglomeration, which also affects the reaction efficiency.

[0012] Preferably, in step S2, the tungsten-rhenium alloy waste powder is cleaned to remove surface impurities.

[0013] Preferably, in step S2, during the reaction process, the power density of the ultrasonic treatment is 30-50 W / L, and the operating frequency is 25-40 kHz. Under the ultrasonic treatment with the above power density and operating frequency, while ensuring the continuous renewal of the reaction interface, the uniformity of the dispersion of the introduced oxygen bubbles can be improved, allowing the introduced oxygen to come into contact with more reaction interfaces and further interact with H2O2, thereby improving the oxidation efficiency of tungsten and rhenium and thus increasing the leaching rate of tungsten and rhenium.

[0014] Preferably, in step S2, stirring is applied simultaneously during the reaction process at a speed of 50-150 rpm. Further stirring at a relatively slow speed, combined with ultrasonic treatment, enhances the mass transfer between H2O2 and the alloy surface. This also prevents the introduced oxygen from being broken up too quickly and leaving the reactor too rapidly, thus reducing the oxygen bubble's ability to replenish oxidation. Therefore, it better balances the process parameters, further promoting reaction efficiency, improving reaction quality, and optimizing the high-selectivity leaching rate of tungsten and rhenium.

[0015] Preferably, in S2, the reaction temperature is 60-80°C and the reaction time is 2-5 hours. Under the synergistic effect of the strongly alkaline hydrogen peroxide-assisted oxidation system of this invention, combined with supplementary oxidation with oxygen and / or ultrasonic and / or stirring treatments, the reaction temperature is controlled at a low temperature and the reaction time is short, thus achieving efficient oxidation of tungsten and rhenium, i.e., achieving high selective leaching rates of tungsten and rhenium, and greatly improving the recovery rate of tungsten and rhenium.

[0016] Preferably, in S2, the strong alkaline substance includes at least one of NaOH and KOH. More preferably, the strong alkaline substance is NaOH. Both NaOH and KOH can provide OH-. - However, the solubility of potassium tungstate produced by the reaction of KOH and tungsten is slightly lower than that of sodium tungstate. When the tungsten content is high, it is easy to cause precipitation and hinder the subsequent reaction. Therefore, considering all factors, NaOH is a better choice.

[0017] Preferably, in S2, the solid-liquid ratio of the reaction is 1 g: 8~15 mL.

[0018] Preferably, in S2, the inlet flow rate of the oxidizing gas is 0.2-1.0 VVM; and / or, the average diameter of the bubbles formed by the oxidizing gas in the reactor is 10-50 μm. "VVM" represents "gas volume / liquid volume per minute". A flow rate of 0.2-1.0 VVM plays a role in stabilizing mass transfer; too high a flow rate can easily lead to bubble coalescence, while too low a flow rate can easily lead to insufficient mass transfer. Regarding the bubble diameter range, the smaller the bubble, the larger the specific surface area; however, if the bubble is too small, insufficient buoyancy may cause retention in the liquid phase. Therefore, it is necessary to ensure that the average bubble diameter is 10-50 μm to maximize the supplementary oxidation capacity of the oxygen bubbles. The diameter of the passing bubbles can be controlled by matching the pore size and pore structure of the microporous gas distributor, while also considering the aeration rate, pressure, and liquid viscosity for comprehensive matching.

[0019] Preferably, in step S2, the oxidizing gas includes oxygen. Preferably, in step S2, the volume concentration of oxygen in the oxidizing gas is not less than 90%. Preferably, in step S2, the oxidizing gas is oxygen. Oxygen, as an oxidizing gas, can balance mass transfer and oxidation, while reducing side effects of the reaction and optimizing the reaction process and leaching efficiency. If ozone is used, although ozone will enhance mass transfer and oxidation, its strong oxidizing properties can easily lead to peroxidation, causing some impurities to be oxidized and dissolved, and also causing hydrogen peroxide decomposition, resulting in the ineffective consumption of the main oxidant. Moreover, ozone is easily decomposed under the temperature and strongly alkaline environment of this scheme, and its introduction must be accelerated to maintain the concentration. At the same time, ozone is more sensitive to pH and temperature, which can easily lead to reaction instability, and the exothermic effect of ozone decomposition causes temperature window changes, which is not conducive to the stability and safety of the reaction. Therefore, using oxygen can better balance multiple performance aspects, making the reaction efficient and safe.

[0020] Preferably, in S3, the specific operation of solid-liquid separation is as follows: collect the product after the reaction is completed, and send the product into a filter press or centrifuge for solid-liquid separation.

[0021] Preferably, in step S3, tungsten-containing ions and rhenium-containing ions in the leachate are separated using an ion exchange method.

[0022] Preferably, the ion exchange method is a strongly basic anion exchange method.

[0023] Preferably, in S3, the leachate contains tungsten ions including WO4. 2- (Tungstate), containing rhenium ions including ReO4 - (High rhenium ion). Using an alkaline hydrogen peroxide synergistic oxidation system, the tungsten and rhenium in the leachate obtained after the reaction of tungsten-rhenium alloy waste powder are mainly in the form of WO4. 2- ReO4 - It exists to facilitate subsequent separation and purification.

[0024] Preferably, in S3, the specific operation for separating tungsten-containing ions and rhenium-containing ions in the leachate using ion exchange is as follows: (1) Adjust the pH of the leachate to 9.0~10.0, then pass the leachate into a chromatography column of a strongly basic anion exchange resin at a flow rate of 2-4 BV / h, and collect the effluent as a tungsten-containing solution; (2) Elute the chromatography column with an eluent to displace the rhenium-containing ions adsorbed in the chromatography column, and collect the eluent as a rhenium-containing solution. Under pH=9.0~10.0 conditions, the quaternary ammonium functional groups on the resin react with the monovalent perrhenate group (ReO4). - ) exhibits extremely strong affinity and selectivity, and will firmly adsorb it; while divalent tungstate (WO4) ions... 2-The binding force between the rhenium and the resin is much weaker, so it will preferentially penetrate the resin column and be collected with the effluent (rhenium-poor tungsten-rich liquid).

[0025] Preferably, in step (1), the pH of the leachate is adjusted to 9.0-10.0 using sulfuric acid or hydrochloric acid. Preferably, in step (1), the chromatography column of the strongly basic anion exchange resin includes a chromatography column of type D201. D201 resin is a styrene-divinylbenzene copolymer-based strongly basic anion exchange resin with quaternary ammonium groups (-N⁺(CH3)3), specifically designed for highly selective adsorption of specific anions (such as ReO4). - MoO4 2- (etc.) design. Preferably, in step (2), the eluent includes a 1-2 M perchloric acid (HClO4) solution or a 2-4 M ammonium thiocyanate (NH4SCN) solution. The above eluent can remove the adsorbed ReO4 - The efficient displacement yields a small volume of high-purity rhenium concentrate (elution solution) with a high rhenium concentration.

[0026] Preferably, in step S3, the specific operation for further processing the obtained tungsten ion-containing solution is as follows: calcium tungstate is precipitated by adding a calcium salt, or ammonium paratungstate (APT) is obtained by acidification and crystallization. Preferably, the calcium salt includes calcium chloride. Further, after obtaining calcium tungstate or ammonium paratungstate, metallic tungsten can be obtained through relevant processing operations.

[0027] Preferably, in S3, the specific operation for subsequent processing of the obtained rhenium ion-containing solution is as follows: after subsequent processing operations such as impurity removal, precipitation or crystallization, rhenium salt or metallic rhenium is obtained.

[0028] The method for recovering tungsten and rhenium from tungsten-rhenium alloy waste provided by this invention achieves groundbreaking technical results through fundamental chemical system innovation and synergistic enhancement of multiple physical fields. First, the use of an alkaline peroxide system fundamentally solves the long-standing problem of surface passivation in the wet recovery of W-Re alloys, making complete leaching possible under mild conditions (<100℃). Second, the synergistic introduction of micro-oxygen bubbles (introduction of oxidizing gas) and / or ultrasonic treatment greatly enhances the reaction kinetics, increasing the leaching rate several times compared to traditional methods and shortening the reaction time from tens of hours to 2-5 hours. Third, the entire leaching process is green and environmentally friendly, avoiding high-temperature energy consumption and harmful gas emissions. Finally, combined with mature and efficient ion exchange separation technology, near 100% separation of tungsten and rhenium can be achieved, resulting in tungsten and rhenium products with high purity (>99.9%) and a total recovery rate (>98%) far exceeding existing technologies, possessing extremely high economic value and application prospects. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0030] Example 1

[0031] The following steps are used to recycle W and Re from W-Re binary alloy wires, sheets, or block waste:

[0032] S1. Collect tungsten-rhenium alloy waste, calcine the waste at 950℃ for 2 hours, and introduce hydrogen atmosphere during the calcination process for hydrogen embrittlement treatment. The flow rate of the hydrogen atmosphere is 350 mL / min. After cooling, mechanically crush the hydrogen-embrittled tungsten-rhenium alloy waste, such as by ball milling or hammer milling, and then screen it through a multi-stage vibrating screen to select irregular particle powder in the particle size range of 0.1-1.0 mm, which is the tungsten-rhenium alloy waste powder.

[0033] S2. The tungsten-rhenium alloy waste powder obtained in S1 is cleaned to remove surface impurities. The cleaned tungsten-rhenium alloy waste powder is then placed in a jacketed reactor, which integrates a jacketed temperature control system, an ultrasonic device, a micro-oxygen bubble distributor, and a mechanical stirring device. A sodium hydroxide (NaOH) solution containing hydrogen peroxide (H2O2) is then added to initiate the reaction at 70°C for 3.5 hours. In the NaOH solution, the OH groups dissociated from the NaOH... - The concentration of hydrogen peroxide was 3.0 mol / L, and the mass fraction of hydrogen peroxide in the NaOH solution was 10%. During the reaction, oxygen was continuously introduced into the reactor simultaneously through a micro-oxygen bubble distributor to form bubbles with an average diameter of 20-30 μm. The oxygen flow rate was 0.6 VVM. The diameter of the passing bubbles was controlled by matching the pore size and pore structure of the microporous distributor, combined with the aeration rate, pressure, and liquid viscosity. During the reaction, ultrasonic treatment and mechanical stirring were applied simultaneously. The power density of the ultrasonic treatment was 40 W / L, the working frequency was 35 kHz, and the stirring speed was 100 rpm.

[0034] S3. After the reaction is complete, the reaction product is sent to a filter press or centrifuge for solid-liquid separation. The purified leachate is collected, and the pH of the leachate is carefully adjusted to 9.0-10.0 with dilute sulfuric acid or hydrochloric acid. Then, the leachate adjusted to the specific pH value is pumped at a flow rate of 2-4 BV / h through a chromatography column packed with D201 type or equivalent strong basic anion exchange resin. Calcium chloride is added to the collected effluent (containing tungsten ion solution, i.e., tungsten-rich effluent) to precipitate calcium tungstate, or high-purity ammonium paratungstate (APT) product is obtained through acidification and crystallization. Using 1-2 A high-purity rhenium concentrate (eluent) is obtained by eluting the chromatography column with a solution of mol / L perchloric acid (HClO4) or 2-4 mol / L ammonium thiocyanate (NH4SCN) to obtain a high-purity rhenium concentrate. The high-purity rhenium concentrate is then subjected to impurity removal, precipitation (such as rhenium sulfide precipitation) or direct crystallization to finally obtain high-purity ammonium perrhenate or metallic rhenium powder.

[0035] The leaching rate and recovery rate of tungsten and rhenium provided in this embodiment are tested and calculated. The specific test method and calculation method are as follows: (1) Leaching rate: The tungsten-rhenium alloy waste powder in S1 is sampled and first prepared into a solution. Then, the contents of tungsten and rhenium are measured by ICP-OES or IPC-MS respectively, and the mass of tungsten and rhenium in the raw material is calculated by reverse calculation. Then, the purified leachate obtained in S3 is directly sampled, and the contents of tungsten and rhenium in the indium-containing leachate are measured by ICP-OES or IPC-MS. The mass of tungsten and rhenium in the leachate is calculated. The leaching rate of tungsten and rhenium is calculated using the results of the above two steps.

[0036] (2) Recovery rate: The tungsten-rhenium alloy waste powder in S1 was sampled, first prepared into a solution, and then the contents of tungsten and rhenium were determined by ICP-OES or IPC-MS respectively. The mass of tungsten and rhenium in the raw material was calculated by reverse calculation. Then, the mass of tungsten and rhenium in the ammonium paratungstate (APT) product finally obtained in S3 and in ammonium perrhenate or metallic rhenium powder was calculated. The recovery rate of tungsten and rhenium was calculated using the results of the above two steps.

[0037] The final leaching rate of tungsten was 99.95%, and the recovery rate was 99.2%; the leaching rate of rhenium was 99.97%, and the recovery rate was 99.3%.

[0038] Example 2

[0039] The method for recycling W and Re from W-Re binary alloy wires, sheets, or block waste in this embodiment differs from that in Example 1 in that the power density of the ultrasonic treatment in S2 is 65 W / L; the rest is the same as in Example 1.

[0040] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 98.64% and the recovery rate was 97.2%; the leaching rate of rhenium was 98.35% and the recovery rate was 97.3%.

[0041] Example 3

[0042] The method for recycling W and Re from W-Re binary alloy wires, sheets, or block waste in this embodiment differs from that in Embodiment 1 in that the ultrasonic treatment frequency in S2 is 15 kHz; the rest is the same as in Embodiment 1.

[0043] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 97.08% and the recovery rate was 96.1%; the leaching rate of rhenium was 97.84% and the recovery rate was 96.6%.

[0044] Example 4

[0045] In this embodiment, the method for recycling W and Re from W-Re binary alloy wires, sheets, or block waste differs from that in Embodiment 1 in that the mechanical stirring speed in S2 is 40 rpm; the rest is the same as in Embodiment 1.

[0046] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 97.27% and the recovery rate was 96.0%; the leaching rate of rhenium was 97.12% and the recovery rate was 95.8%.

[0047] Example 5

[0048] In this embodiment, the method for recycling W and Re from W-Re binary alloy wires, sheets, or block waste differs from that in Embodiment 1 in that the oxygen flow rate in S2 is 0.1 VVM; the rest is the same as in Embodiment 1.

[0049] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 95.51% and the recovery rate was 94.8%; the leaching rate of rhenium was 95.07% and the recovery rate was 94.5%.

[0050] Example 6

[0051] In this embodiment, the method for recycling W and Re from W-Re binary alloy wires, sheets, or block waste differs from that in Embodiment 1 in that the oxygen flow rate in S2 is 1.2 VVM; the rest is the same as in Embodiment 1.

[0052] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 99.23% and the recovery rate was 98.8%; the leaching rate of rhenium was 99.43% and the recovery rate was 99.1%.

[0053] Example 7

[0054] The method for recycling W and Re from W-Re binary alloy wires, sheets, or block waste in this embodiment differs from that in Example 1 in that, in S2, the average diameter of the bubbles formed by oxygen in the reactor is controlled to be 3~8μm; the rest is the same as in Example 1.

[0055] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 99.22% and the recovery rate was 98.9%; the leaching rate of rhenium was 99.31% and the recovery rate was 99.0%.

[0056] Example 8

[0057] The method for recycling W and Re from W-Re binary alloy wires, sheets, or block waste in this embodiment differs from that in Example 1 in that, in S2, the average diameter of the bubbles formed by oxygen in the reactor is controlled to be 55~65μm; the rest is the same as in Example 1.

[0058] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 99.14% and the recovery rate was 98.5%; the leaching rate of rhenium was 99.12% and the recovery rate was 98.9%.

[0059] Comparative Example 1

[0060] The following steps are used to recycle W and Re from W-Re binary alloy wires, sheets, or block waste:

[0061] S1. Mechanically crush the tungsten-rhenium alloy waste, such as by ball milling or hammer milling, and then sieve it through a multi-stage vibrating screen to obtain irregular particle powder with a particle size in the range of 0.1-1.0 mm, thus obtaining tungsten-rhenium alloy waste powder;

[0062] S2. The tungsten-rhenium alloy waste powder obtained in S1 is cleaned to remove surface impurities. The cleaned tungsten-rhenium alloy waste powder is placed in a reactor, and a leaching agent is added to the reactor at a liquid-to-solid ratio of 7.5:1 (mass ratio). The leaching agent is sulfuric acid (H2SO4, 0.55-3.5 mol / L) + oxidant (H2O2, 0.66-9 mol / L). The reaction is carried out at 70℃ for 3.5 hours.

[0063] S3. After the reaction is complete, the reaction product is sent to a filter press or centrifuge for solid-liquid separation. The purified leachate is collected and HReO4 is selectively extracted with an amine extractant (such as Alamine 336). Tungsten remains in the aqueous phase. The supported organic phase (containing rhenium) is back-extracted with industrial ammonia or sodium hydroxide solution to return the rhenium ions to the aqueous phase, resulting in a perrhenic acid solution. The perrhenic acid solution is evaporated and crystallized to obtain ammonium perrhenate or sodium perrhenate, which is then reduced with hydrogen to obtain metallic rhenium. The tungsten-containing aqueous phase obtained above is the tungsten-containing solution. The tungsten-containing solution is dissolved in ammonia and then evaporated and crystallized to obtain ammonium tungstate.

[0064] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 94.28% and the recovery rate was 90.4%; the leaching rate of rhenium was 92.06% and the recovery rate was 88.3%.

[0065] Comparative Example 2

[0066] In this comparative example, the method for recovering W and Re from W-Re binary alloy wire, sheet, or block waste differs from Example 1 in that, in S2, the OH groups dissociated from NaOH in the strongly alkaline solution... - The concentration was 5.0 mol / L; the rest was the same as in Example 1.

[0067] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 95.02% and the recovery rate was 93.2%; the leaching rate of rhenium was 94.32% and the recovery rate was 92.8%.

[0068] Comparative Example 3

[0069] In this comparative example, the method for recovering W and Re from W-Re binary alloy wire, sheet, or block waste differs from Example 1 in that, in S2, the mass fraction of hydrogen peroxide in the strongly alkaline solution is 3%; the rest is the same as in Example 1.

[0070] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 92.72% and the recovery rate was 90.3%; the leaching rate of rhenium was 92.43% and the recovery rate was 89.2%.

[0071] Comparative Example 4

[0072] In this comparative example, the method for recovering W and Re from W-Re binary alloy wire, sheet, or block waste differs from Example 1 in that oxygen is not continuously introduced into the reactor in step S2; otherwise, it is the same as Example 1.

[0073] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 93.34% and the recovery rate was 91.0%; the leaching rate of rhenium was 92.05% and the recovery rate was 90.5%.

[0074] Comparative Example 5

[0075] The method for recycling W and Re from W-Re binary alloy wires, sheets, or block waste in this comparative example differs from Example 1 in that ultrasonic treatment is not applied in S2; the rest is the same as in Example 1.

[0076] Referring to the testing and calculation methods for the leaching rate and recovery rate of tungsten and rhenium provided in Example 1, the leaching rate of tungsten was 88.21% and the recovery rate was 87.9%; the leaching rate of rhenium was 87.51% and the recovery rate was 86.3%.

[0077] Test results statistics and analysis

[0078] The results of the relevant parameters tested for all the above embodiments and comparative examples are shown in Table 1.

[0079] Table 1. Results of relevant parameters tested in the examples and comparative examples.

[0080]

[0081] As shown in Table 1, the processing method provided by this invention can effectively improve the leaching rate of tungsten and rhenium from tungsten-rhenium alloy waste, and also effectively improve the recovery rate of tungsten and rhenium. Moreover, this method can recover tungsten and rhenium simultaneously, achieving rapid and efficient recovery of tungsten and rhenium. For specific details, please refer to the performance data of Examples 1-8 above.

[0082] Comparative Example 1 uses conventional tungsten and rhenium recovery methods, which require strong acids and easily generate insoluble tungstate passivation layers, thus reducing the leaching and recovery rates of tungsten and rhenium.

[0083] In Comparative Example 2, the concentration of NaOH solution was too high, and the decomposition rate of H2O2 was too fast (exponentially increasing). Its utilization rate as an oxidant dropped sharply, which was not conducive to the full and efficient dissolution of tungsten and rhenium, and also reduced the recovery rate of tungsten and rhenium.

[0084] In Comparative Example 3, the mass fraction of hydrogen peroxide in the strongly alkaline solution was too low, which was not conducive to the full oxidation of the tungsten-rhenium alloy waste, thus significantly reducing the leaching rate and recovery rate of tungsten and rhenium.

[0085] In Comparative Example 4, the intermittent introduction of oxygen during the leaching reaction process prevented timely replenishment of the oxidizing capacity of H2O2, increasing the decomposition loss and total amount of H2O2 used, and also hindering the improvement of the leaching rate and recovery rate of tungsten and rhenium.

[0086] In Comparative Example 5, the lack of ultrasound during the leaching reaction resulted in a decrease in the contact efficiency between the reagent and the particle surface. Furthermore, the reaction product layer gradually thickened and became denser, hindering the continued reaction of the inner alloy layer and forming a "passivation effect," which was detrimental to the leaching of tungsten and rhenium, and consequently also hindered the improvement of the recovery rate of tungsten and rhenium.

[0087] Further comparison of Examples 1 and 2-9 reveals that the excessively high power density of the ultrasonic treatment in Example 2 and the excessively low operating frequency of the ultrasonic treatment in Example 3 both resulted in a decrease in the leaching and recovery rates of tungsten and rhenium. This indicates that controlling the power density and operating frequency of the ultrasonic treatment within a specific range is more conducive to the synergistic effect of ultrasonic treatment with other process parameters, thereby further improving the leaching and recovery rates of tungsten and rhenium. Similarly, the excessively low rotation speed of the mechanical stirring treatment in Example 4 also failed to fully utilize the stirring effect, such as reducing mass transfer, thus leading to a decrease in the leaching and recovery rates of tungsten and rhenium. The excessively low and high oxygen flow rates in Examples 5 and 6, respectively, also resulted in a decrease in the leaching and recovery rates of tungsten and rhenium. This demonstrates that controlling the oxygen flow rate within a specific range is more conducive to balancing the various effects of oxygen bubbles, thereby promoting the leaching of tungsten and rhenium. In Examples 7 and 8, the average diameter of the oxygen bubbles was too small and too large, respectively, which also reduced the leaching and recovery rates of tungsten and rhenium. This indicates that the average diameter of the introduced oxygen bubbles also needs to be kept within a specific range to be more conducive to the leaching of tungsten and rhenium and to improve the recovery rate of tungsten and rhenium.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention, but such modifications or substitutions are all within the scope of protection of the present invention.

Claims

1. A method of recovering tungsten and rhenium from a tungsten-rhenium alloy scrap material, characterized by, The method comprises the following steps: S1. Collecting tungsten-rhenium alloy waste, crushing to obtain tungsten-rhenium alloy waste powder; S2. The cleaned tungsten-rhenium alloy waste powder is put into a reactor, and then a strong alkaline solution containing hydrogen peroxide is added to the reactor for reaction; in the strong alkaline solution, the concentration of OH - dissociated from a strong alkaline substance is 2.0-4.0 mol / L, and the mass fraction of hydrogen peroxide in the strong alkaline solution is 5-15%; during the reaction, an oxidizing gas is continuously introduced into the reactor and ultrasonic treatment is applied simultaneously. S3. After the reaction, solid-liquid separation is performed to collect the leaching solution, and then the tungsten-containing ions and the rhenium-containing ions in the leaching solution are separated to obtain a tungsten-containing ion solution and a rhenium-containing ion solution, respectively, and after subsequent treatment, tungsten salt or metallic tungsten and rhenium salt or metallic rhenium are obtained.

2. The process of claim 1 for recovering tungsten and rhenium from tungsten-rhenium alloy scrap, characterized by: In the S2, the power density of the ultrasonic treatment is 30-50 W / L, and the working frequency is 25-40 kHz during the reaction.

3. The method of recovering tungsten and rhenium from tungsten-rhenium alloy scrap of claim 1, wherein In the S2, stirring treatment is applied synchronously during the reaction, and the stirring speed is 50-150 rpm.

4. The method of recovering tungsten and rhenium from tungsten-rhenium alloy scrap of claim 1, wherein: In the S2, the reaction temperature is 60-80℃, and the reaction time is 2-5h.

5. The method of recovering tungsten and rhenium from tungsten-rhenium alloy scrap of claim 1, wherein: In the S2, the solid-liquid ratio of the reaction is 1 g:8-15 mL.

6. The method of recovering tungsten and rhenium from tungsten-rhenium alloy scrap of claim 1, wherein: In the S2, the flow rate of the oxidative gas is 0.2-1.0 VVM. And / or, the average diameter of the gas bubbles formed by the oxidative gas in the reactor is 10-50 μm.

7. The method of recovering tungsten and rhenium from tungsten-rhenium alloy scrap of claim 1, wherein: In the S2, the oxidative gas comprises oxygen.

8. The method of recovering tungsten and rhenium from tungsten-rhenium alloy scrap of claim 1, wherein: In the S3, the ion exchange method is used to separate the tungsten-containing ions and the rhenium-containing ions in the leaching solution.

9. The method of recovering tungsten and rhenium from tungsten-rhenium alloy scrap of claim 1, wherein: In the S3, the tungsten-containing ions in the leachate include WO4 2- , and the rhenium-containing ions include ReO4 - .

10. The method of recovering tungsten and rhenium from tungsten-rhenium alloy scrap of claim 8 wherein, In the S3, the specific operation of separating the tungsten-containing ions and the rhenium-containing ions in the leaching solution by using the ion exchange method is as follows: (1) The pH of the leaching solution is adjusted to 9.0-10.0, and then the leaching solution is passed into a chromatographic column filled with strong alkaline anion exchange resin at a flow rate of 2-4 BV / h, and the obtained effluent is the tungsten-containing ion solution; (2) The chromatographic column is eluted with an eluent to displace the rhenium-containing ions adsorbed in the chromatographic column, and the obtained eluate is the rhenium-containing ion solution.

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