Ultrafine rhenium powder with low oxygen content and preparation method thereof

Abstract

The invention provides low-oxygen-content superfine rhenium powder and a preparation method thereof, and relates to the field of metal powder preparation. Mixing the ammonium rhenate solution, citric acid and polyethylene glycol, and performing ultrasonic treatment and spray drying on the obtained mixture to obtain solid powder; in reducing gas, the solid powder is subjected to reduction roasting, and reduced powder is obtained; and in a vacuum environment, the reduced powder is subjected to deoxidation treatment, and the low-oxygen-content superfine rhenium powder is obtained. The method is simple and convenient to operate, good in economical efficiency and convenient for industrial batch production.

Description

Technical Field

[0001] The present application relates to the field of metal powder preparation, and in particular to an ultrafine rhenium powder with a low oxygen content and a preparation method thereof. Background Art

[0002] Rhenium metal has a melting point of 3180℃, second only to tungsten at 3410℃, and is a refractory metal. Rhenium is rare and dispersed in the earth's crust, and is one of the rarest elements in the earth's crust. Its average content is estimated to be one billionth, and it is a dispersed metal. Rhenium has developed into an important strategic resource. As an important alloy element, its smelting quality has strict requirements on indicators such as metal purity and gas content.

[0003] In industry, the method of ammonium rhenate reduction is commonly used to prepare metal rhenium powder. Existing studies have shown that ammonium rhenate reacts to form rhenium powder very quickly under hydrogen, which is completely different from tungsten and molybdenum, which produce different intermediate oxides at different temperature stages under hydrogen atmosphere. Ammonium rhenate basically completes the phase transformation process from ammonium rhenate to rhenium powder at about 400-500°C under hydrogen atmosphere. The reaction speed is too fast, resulting in impurities such as oxygen in the rhenium powder not having time to precipitate, so the oxygen content of the rhenium powder is generally high. At the same time, the rapid reaction also leads to the large microscopic size of the rhenium powder, and a large number of flaky powder hard agglomerates are formed. The electron microscope photo of the single particle size of the rhenium powder shows that the general size is >50μm, which affects the powder molding performance.

[0004] Therefore, there is an urgent need to provide a method for preparing ultrafine rhenium powder with low oxygen content to solve the problems of coarse particles, flaky appearance and high oxygen content of rhenium powder prepared in the prior art. Summary of the invention

[0005] The purpose of the present application is to provide an ultrafine rhenium powder with low oxygen content and a preparation method thereof to solve the above problems.

[0006] To achieve the above objectives, the present application provides a first aspect of a method for preparing ultrafine rhenium powder with low oxygen content, comprising:

[0007] The ammonium rhenate solution, citric acid and polyethylene glycol are mixed, and the obtained mixture is subjected to ultrasonication and spray drying to obtain a solid powder;

[0008] The solid powder is subjected to reduction roasting in a reducing gas to obtain a reduced powder;

[0009] The reduced powder is subjected to a deoxidation treatment under a vacuum environment to obtain ultrafine rhenium powder with a low oxygen content.

[0010] Optionally, the ammonium rhenate solution is prepared by mixing ammonium rhenate and water in a mass ratio of 1:(3-5).

[0011] Optionally, the mass ratio of the citric acid to the ammonium rhenate solution is (1 - 5):100;

[0012] The mass ratio of the polyethylene glycol to the ammonium rhenate solution is (5 - 20):100.

[0013] Optionally, the preparation method of the ultrafine rhenium powder with low oxygen content satisfies at least one of the following conditions:

[0014] A. The temperature of the mixture during ultrasonic treatment is 80°C - 100°C;

[0015] B. The ultrasonic frequency during ultrasonic treatment is 20 kHz - 30 kHz, and the time is 30 min - 60 min.

[0016] Optionally, the preparation method of the ultrafine rhenium powder with low oxygen content satisfies at least one of the following conditions:

[0017] A. The diameter of the spray disk for spray drying is ≤50 mm, the atomization working speed is 20000 r / min - 25000 r / min, the inlet temperature is 180°C - 220°C, and the feeding rate of the peristaltic pump is 20 mL / min - 50 mL / min;

[0018] B. Before the spray drying, spray preheating is also carried out, and the temperature of the spray preheating is 60°C - 100°C.

[0019] Optionally, the particle size of the solid powder is less than or equal to 1 μm.

[0020] Optionally, the preparation method of the ultrafine rhenium powder with low oxygen content satisfies at least one of the following conditions:

[0021] A. The reducing gas includes hydrogen;

[0022] B. The reduction roasting includes first reduction roasting and second reduction roasting carried out in sequence;

[0023] The temperature of the first reduction roasting is 250°C - 300°C, and the time is 2 h - 4 h;

[0024] The temperature of the second reduction roasting is 600°C - 800°C, and the time is 4 h - 6 h;

[0025] C. The flow rate of the reducing gas during the reduction roasting process is 0.5 m 3 / h - 1.5 m 3 / h.

[0026] Optionally, the preparation method of the ultrafine rhenium powder with low oxygen content satisfies at least one of the following conditions:

[0027] A. The vacuum degree of the vacuum environment is greater than 10 -3 Pa;

[0028] B. The temperature of the deoxidation treatment is 800°C - 900°C, and the time is 4h - 6h.

[0029] The second aspect of the present application provides a low-oxygen-content ultrafine rhenium powder, which is prepared by the preparation method of the low-oxygen-content ultrafine rhenium powder described above.

[0030] Optionally, the oxygen content is less than or equal to 0.1%, and the particle size is 0.8μm - 1.2μm.

[0031] Compared with the prior art, the beneficial effects of the present application include:

[0032] For the preparation method of the low-oxygen-content ultrafine rhenium powder provided by the present application, in order to obtain finer rhenium powder, the ammonium perrhenate aqueous solution dispersed by adding a complexing agent is spray-dried to form atomized droplets and instantaneously dried to obtain ammonium perrhenate ultrafine powder. After deagglomeration - spray drying - reduction roasting, ultrafine rhenium powder is obtained, and vacuum deoxidation is carried out on the rhenium powder to obtain low-oxygen-content ultrafine rhenium powder; this method is simple and convenient to operate, has good economy, and is convenient for industrial mass production.

[0033] The low-oxygen-content ultrafine rhenium powder provided by the present application has low oxygen content, small particle size, and uniform particles. Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope of the present application.

[0035] Figure 1 SEM image of the dried powder prepared in Example 1;

[0036] Figure 2 SEM image of the low-oxygen-content ultrafine rhenium powder prepared in Example 1;

[0037] Figure 3 SEM image of the rhenium powder prepared in Comparative Example 5. Detailed Embodiments

[0038] As used herein, the terms:

[0039] "Prepared by..." is synonymous with "comprising". As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or apparatus comprising the listed elements need not be limited to those elements alone, but may include other elements not expressly listed or elements inherent to such composition, step, method, article or apparatus.

[0040] The conjunctive "consisting of" excludes any unrecited element, step or component. If used in a claim, this phrase renders the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause within the body of a claim rather than immediately following the subject, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0041] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, whether or not the ranges are separately disclosed. For example, when the range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.

[0042] In these examples, unless otherwise specified, the parts and percentages are by mass.

[0043] "Parts by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 2.689 g, etc. If we say that the mass of component A is a parts by mass and the mass of component B is b parts by mass, it means the mass ratio of component A to component B is a:b. Or, it means the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the number of parts by mass, the sum of the parts by mass of all components is not limited to 100 parts.

[0044] "And / or" is used to indicate that either or both of the stated circumstances may occur. For example, A and / or B includes (A and B) and (A or B).

[0045] The first aspect of the present application provides a method for preparing ultrafine rhenium powder with low oxygen content, comprising:

[0046] Mix ammonium perrhenate solution, citric acid and polyethylene glycol, and subject the resulting mixture to ultrasonic treatment and spray drying to obtain solid powder;

[0047] It should be noted that citric acid contains multiple carboxyl groups, which can form stable complexes with rhenium ions, effectively preventing the agglomeration of ammonium perrhenate during spray drying. As a strong complexing agent, citric acid can reduce the concentration of free rhenium ions and the supersaturation of ammonium perrhenate solution to control crystal growth. However, when citric acid is added alone, the viscosity of the ammonium perrhenate solution is low, and it is easily atomized into thin droplets, resulting in the problem of excessive dispersion, increasing the probability of collision between droplets and increasing the risk of agglomeration; the purpose of adding polyethylene glycol (PEG) is to increase the viscosity of the solution. The higher viscosity can reduce the migration rate of free rhenium ions and reduce the possibility of rapid nucleation, thereby making crystal growth slower and more stable. At the same time, an appropriate viscosity of the ammonium perrhenate solution helps to form a stable droplet flow during spray drying, and the droplets will not be overly dispersed, reducing the secondary agglomeration of the ammonium perrhenate powder after spray drying; but when PEG is added alone, since PEG itself does not have the ability to complex metal ions, it cannot directly form a stable complex with rhenium ions and cannot effectively control the concentration of free rhenium ions in the solution, which may lead to irregular or larger particles during the crystallization process; in addition, without the citric acid complexing agent, the ammonium perrhenate in the solution may have local high or low concentrations, resulting in uneven composition inside the droplets during spray drying and affecting the product quality;

[0048] In a reducing gas, subject the solid powder to reduction roasting to obtain reduced powder;

[0049] In a vacuum environment, subject the reduced powder to deoxidation treatment to obtain ultrafine rhenium powder with low oxygen content.

[0050] In some embodiments, the ammonium perrhenate solution is prepared by mixing ammonium perrhenate and water at a mass ratio of 1:(3 - 5).

[0051] Optionally, when preparing the ammonium perrhenate solution, the mass ratio of ammonium perrhenate to water can be 1:3, 1:4, 1:5 or any value between 1:(3 - 5).

[0052] In some embodiments, the mass ratio of citric acid to the ammonium perrhenate solution is (1 - 5):100;

[0053] Optionally, the mass ratio of citric acid to the ammonium perrhenate solution can be 1:100, 2:100, 3:100, 4:100, 5:100 or any value between (1 - 5):100;

[0054] It should be noted that citric acid, as a strong complexing agent, can reduce the concentration of free rhenium ions and control crystal growth by reducing the supersaturation of ammonium perrhenate solution. When the mass ratio of citric acid to ammonium perrhenate solution is less than 1:100, the complexing effect is not obvious; when the mass ratio of citric acid to ammonium perrhenate solution is greater than 5:100, its excessive molecules will be adsorbed on the surface of the formed ammonium perrhenate crystal nuclei in large quantities, hindering the deposition and growth of ammonium perrhenate on the crystal nuclei, thereby reducing the crystal crystallization rate.

[0055] The mass ratio of the polyethylene glycol to the ammonium perrhenate solution is (5 - 20):100.

[0056] Optionally, the mass ratio of polyethylene glycol to ammonium perrhenate solution can be 5:100, 10:100, 15:100, 20:100 or any value between (5 - 20):100.

[0057] The purpose of adding polyethylene glycol (PEG) is to increase the viscosity of the solution. When the mass ratio of polyethylene glycol to ammonium perrhenate solution is less than 5:100, the degree of viscosity increase is small, resulting in a poor effect of forming stable droplets; when the mass ratio of polyethylene glycol to ammonium perrhenate solution is greater than 20:100, the solution viscosity is high, resulting in too large droplets and larger particle sizes of the solid powder after spraying.

[0058] In some embodiments, the preparation method of the ultrafine rhenium powder with low oxygen content satisfies at least one of the following conditions:

[0059] A. The temperature of the mixture during ultrasonic treatment is 80°C - 100°C;

[0060] Optionally, the temperature of the mixture during ultrasonic treatment can be 80°C, 85°C, 90°C, 95°C, 100°C or any value between 80°C - 100°C;

[0061] It should be noted that when the temperature of the mixture during ultrasonic treatment is 80°C - 100°C, the solubility of ammonium perrhenate is relatively high, increasing the ammonium perrhenate content in the unit solution, which can improve the spray drying efficiency and thus facilitate batch production;

[0062] B. The ultrasonic frequency during ultrasonic treatment is 20 kHz - 30 kHz, and the time is 30 min - 60 min.

[0063] Optionally, the ultrasonic frequency during ultrasonic treatment can be 20 kHz, 25 kHz, 30 kHz or any value between 20 kHz - 30 kHz, and the time can be 30 min, 40 min, 50 min, 60 min or any value between 30 min - 60 min.

[0064] It should be noted that ultrasonic dispersion utilizes the locally high temperature and high pressure environment and strong mechanical vibration generated by ultrasonic cavitation, which can effectively break up the ammonium perrhenate aggregates that may exist in the solution and evenly disperse the solute. At the same time, ultrasonic treatment can also promote the precipitation of dissolved gases in the solution, reduce the surface defects of particles caused by gas escape during spray drying, and improve the product quality.

[0065] In some embodiments, the method for preparing the ultra-fine rhenium powder with low oxygen content satisfies at least one of the following conditions:

[0066] A. The diameter of the spray disk for spray drying is ≤50 mm, the atomization working rotational speed is 20000 r / min - 25000 r / min, the inlet temperature is 180°C - 220°C, and the feeding rate of the peristaltic pump is 20 mL / min - 50 mL / min;

[0067] Optionally, the diameter of the spray disk for spray drying can be 10 mm, 20 mm, 30 mm, 40 mm, 50 mm or any value ≤50 mm, the atomization working rotational speed can be 20000 r / min, 21000 r / min, 22000 r / min, 23000 r / min, 24000 r / min, 25000 r / min or any value between 20000 r / min - 25000 r / min, the inlet temperature can be 180°C, 190°C, 200°C, 210°C, 220°C or any value between 180°C - 220°C, and the feeding rate of the peristaltic pump can be 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min or any value between 20 mL / min - 50 mL / min;

[0068] It should be noted that using a small-diameter atomization disk, atomizing at a very high rotational speed, with an inlet temperature of 180 - 220°C, which is lower than the thermal decomposition temperature of ammonium perrhenate, can prevent the thermal decomposition and volatilization of ammonium perrhenate, and a slow feeding rate ensures fine atomized particles and good drying effect;

[0069] B. Before performing the spray drying, spray preheating is also carried out, and the temperature of the spray preheating is 60°C - 100°C.

[0070] Optionally, the temperature of the spray preheating can be 60°C, 70°C, 80°C, 90°C, 100°C or any value between 60°C - 100°C.

[0071] It should be noted that the main function of spray preheating is to prevent blockage of pipelines and nozzles. The peristaltic pump liquid delivery pipeline before spraying is at room temperature. When the heated solution first passes through these pipelines, sudden temperature drop is likely to cause crystallization and precipitation, resulting in blockage of parts such as pipelines and nozzles, and malfunction of the production process. Preheating to 60°C - 100°C in advance can ensure the smooth progress of production.

[0072] In some embodiments, the particle size of the solid powder is less than or equal to 1 μm.

[0073] Optionally, the particle size of the solid powder can be 0.1, 0.2, 0.3, 0.5, 1 μm or any value less than or equal to 1 μm.

[0074] In some embodiments, the method for preparing the ultrafine rhenium powder with low oxygen content satisfies at least one of the following conditions:

[0075] A. The reducing gas includes hydrogen;

[0076] B. The reduction roasting includes a first reduction roasting and a second reduction roasting carried out in sequence;

[0077] The temperature of the first reduction roasting is 250°C - 300°C, and the time is 2 h - 4 h;

[0078] Optionally, the temperature of the first reduction roasting can be 250°C, 260°C, 270°C, 280°C, 290°C, 300°C or any value between 250°C - 300°C, and the time can be 2 h, 3 h, 4 h or any value between 2 h - 4 h;

[0079] The temperature of the second reduction roasting is 600°C - 800°C, and the time is 4 h - 6 h;

[0080] Optionally, the temperature of the second reduction roasting can be 600°C, 650°C, 700°C, 750°C, 800°C or any value between 600°C - 800°C, and the time can be 4 h, 5 h, 6 h or any value between 4 h - 6 h;

[0081] It should be noted that a low-temperature first reduction roasting is carried out to avoid the volatilization and deposition during the reduction of ammonium perrhenate to rhenium powder caused by too violent primary reduction, resulting in the growth of powder particles. A medium-temperature second reduction roasting is carried out. After reduction, the oxygen content of the powder is relatively high, and vacuum deoxidation is used;

[0082] C. The flow rate of the reducing gas during the reduction roasting is 0.5 m 3 / h - 1.5 m 3 / h.

[0083] Optionally, the flow rate of the reducing gas during the reduction roasting can be 0.5 m 3 / h, 1 m 3 / h, 1.5 m 3 / h or any value between 0.5 m 3 / h - 1.5 m 3 / h.

[0084] In some embodiments, the method for preparing the ultrafine rhenium powder with low oxygen content satisfies at least one of the following conditions:

[0085] A. The vacuum degree of the vacuum environment is greater than 10 -3 Pa;

[0086] Optionally, the vacuum degree of the vacuum environment can be 10 -5 Pa, 10 -4 Pa or any value between higher than 10 -3 Pa;

[0087] B. The temperature of the deoxidation treatment is 800°C - 900°C, and the time is 4h - 6h.

[0088] Optionally, the temperature of the deoxidation treatment can be 800°C, 850°C, 900°C or any value between 800°C - 900°C, and the time can be 4h, 5h, 6h or any value between 4h - 6h.

[0089] The second aspect of the present application provides an ultrafine rhenium powder with low oxygen content, which is prepared by the method for preparing the ultrafine rhenium powder with low oxygen content.

[0090] In some embodiments, the oxygen content is less than or equal to 0.1%, and the particle size is 0.8μm - 1.2μm.

[0091] Optionally, the oxygen content can be 0.001%, 0.01%, 0.1% or any value less than or equal to 0.1%, and the particle size can be 0.8μm, 0.9μm, 1.0μm, 1.1μm, 1.2μm or any value between 0.8μm - 1.2μm.

[0092] The following will describe the implementation solutions of the present application in detail with specific embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are followed. For the reagents or instruments not specified for the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0093] Example 1

[0094] This example provides a method for preparing an ultrafine rhenium powder with low oxygen content, and the specific steps are as follows:

[0095] S1: Prepare an ammonium perrhenate solution according to the mass ratio of ammonium perrhenate to high-purity water of 1:4, heat and stir the mixed solution until it is clear; add citric acid and polyethylene glycol to the ammonium perrhenate solution, wherein the mass ratio of citric acid to the ammonium perrhenate solution is 3:100, and the mass ratio of polyethylene glycol (PEG) to the ammonium perrhenate solution is 10:100;

[0096] S2: Ultrasonically disperse the mixed solution obtained in S1, and maintain the solution temperature at 80 - 85 °C; the ultrasonic frequency is 20 kHz, and the time is 40 min;

[0097] S3: Preheat the spray pipeline and spray system for spray drying with pure water at 80 °C;

[0098] S4: Spray - dry the dispersed mixed solution in step S2 to obtain dry powder with a single - particle size less than 1 μm. The SEM of this dry powder is as Figure 1 shown; among them, the diameter of the spray disk for spray drying is 50 mm, the atomization working rotational speed is 20000 r / min, the inlet temperature is 200 °C - 205 °C, and the feeding rate of the peristaltic pump is 30 mL / min;

[0099] S5: After taking out the powder in step S4, load it into a molybdenum boat and place it in a hydrogen - atmosphere tubular furnace for first - stage and second - stage reduction roasting to obtain reduced powder; among them, the temperature of the first - stage reduction roasting is 260 °C and the time is 3 h; the temperature of the second - stage reduction roasting is 750 °C and the time is 5 h; the flow rate of hydrogen is 1.0 m 3 / h;

[0100] S6: Deoxidize the reduced powder in step S5 in a vacuum heating furnace to obtain ultrafine rhenium powder with a low oxygen content. The SEM of this ultrafine rhenium powder with a low oxygen content is as Figure 2 shown, where the left figure is at a magnification of 1000 times and the right figure is at a magnification of 5000 times.

[0101] Example 2

[0102] The difference from Example 1 is that the mass ratio of citric acid to ammonium perrhenate solution is 5:100, and the mass ratio of polyethylene glycol (PEG) to ammonium perrhenate solution is 20:100.

[0103] Example 3

[0104] The difference from Example 1 is that the diameter of the spray disk for spray drying is 40 mm, the atomization working rotational speed is 25000 r / min, the inlet temperature is 205 °C - 220 °C, and the feeding rate of the peristaltic pump is 50 mL / min.

[0105] Example 4

[0106] The difference from Example 1 is that the temperature of the first - stage reduction roasting is 300 °C and the time is 4 h; the temperature of the second - stage reduction roasting is 800 °C and the time is 6 h; the flow rate of hydrogen is 1.5 m 3 / h.

[0107] Comparative Example 1

[0108] The difference from Example 1 is that in step S5, only one-stage reduction roasting is carried out, the temperature is 600°C - 800°C, and the time is 6h.

[0109] Comparative Example 2

[0110] The difference from Example 1 is that citric acid is not added in step S1.

[0111] Comparative Example 3

[0112] The difference from Example 1 is that polyethylene glycol is not added in step S1.

[0113] Comparative Example 4

[0114] The difference from Example 1 is that the mass ratio of citric acid to ammonium perrhenate solution is 20:100, and the mass ratio of polyethylene glycol (PEG) to ammonium perrhenate solution is 30:100.

[0115] Comparative Example 5

[0116] The difference from Example 1 is that neither citric acid nor polyethylene glycol is added in step S1.

[0117] Comparative Example 6

[0118] The difference from Example 1 is that ammonium perrhenate crystals obtained by the ammonium perrhenate solution freeze crystallization method are used to prepare rhenium powder by a traditional process of one-stage reduction roasting at 450°C with a hydrogen flow rate of 1.5 m 3 / h and two-stage reduction roasting at 850°C with a hydrogen flow rate of 1.5 m 3 / h without vacuum deoxidation treatment.

[0119] The SEM of the prepared rhenium powder is as Figure 3 shown, where the left figure is at a magnification of 1000 times and the right figure is at a magnification of 5000 times.

[0120] Comparative Example 7

[0121] The difference from Example 1 is that no deoxidation treatment is carried out.

[0122] The material parameters of the rhenium powder prepared in the above examples and comparative examples are shown in Table 1.

[0123] Table 1 Material Parameters

[0124]

[0125]

[0126] Analysis:

[0127] As can be seen from Table 1: In Examples 1-4, rhenium powder with an average particle size in the range of 0.8-1.2 μm can be obtained; in Comparative Example 1, directly subjecting the ultrafine powder obtained by spray drying to secondary reduction and high-temperature roasting will cause the powder to grow rapidly; in Comparative Examples 2-5, adding citric acid or polyethylene glycol alone or adding beyond the scope will all cause a slight increase in the final particle size of the rhenium powder; in Comparative Example 6, the size of the rhenium powder after reduction of ammonium perrhenate produced by the conventional crystallization method is significantly coarser; in Comparative Example 7, without vacuum annealing, the particle size remains basically unchanged. In terms of oxygen content, the oxygen content of the rhenium powder after vacuum treatment is less than 0.1%, while the oxygen content of the rhenium powder obtained by secondary reduction roasting using the ammonium perrhenate solution freeze crystallization method in Comparative Example 6 is 0.24%, and the oxygen content of the rhenium powder without vacuum deoxidation treatment in Comparative Example 7 is 0.20%, indicating that the effect of vacuum deoxidation treatment is very significant.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0129] In addition, those skilled in the art can understand that although some of the embodiments herein include certain features included in other embodiments but not others, the combination of the features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the above claims, any one of the claimed embodiments can be used in any combination. The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present application and should not be regarded as an admission or any form of implication that this information constitutes the prior art known to those skilled in the art.

Claims

1. A method for preparing ultrafine rhenium powder with low oxygen content, characterized in that: include: The ammonium rhenate solution, citric acid and polyethylene glycol are mixed, and the obtained mixture is subjected to ultrasonication and spray drying to obtain a solid powder; The solid powder is subjected to reduction roasting in a reducing gas to obtain a reduced powder; The reduced powder is subjected to a deoxidation treatment under a vacuum environment to obtain ultrafine rhenium powder with a low oxygen content.

2. The method for preparing ultrafine rhenium powder with low oxygen content according to claim 1, characterized in that: The ammonium rhenate solution is prepared by mixing ammonium rhenate and water in a mass ratio of 1:3-5.

3. The method for preparing ultrafine rhenium powder with low oxygen content according to claim 1, characterized in that: The mass ratio of the citric acid to the ammonium rhenate solution is 1-5:100; The mass ratio of the polyethylene glycol to the ammonium rhenate solution is 5-20:

100.

4. The method for preparing ultrafine rhenium powder with low oxygen content according to claim 1, characterized in that: At least one of the following conditions is met: A. the temperature of the mixture during the ultrasound is 80°C-100°C; B. The ultrasonic frequency is 20kHz-30kHz and the time is 30min-60min.

5. The method for preparing ultrafine rhenium powder with low oxygen content according to claim 1, characterized in that: At least one of the following conditions is met: A. The spray disk diameter of the spray dryer is ≤50mm, the atomization speed is 20000r / min-25000r / min, the inlet temperature is 180℃-220℃, and the peristaltic pump feed rate is 20mL / min-50mL / min; B. Before the spray drying, spray preheating is also performed, and the spray preheating temperature is 60°C-100°C.

6. The method for preparing ultrafine rhenium powder with low oxygen content according to claim 1, characterized in that: The particle size of the solid powder is less than or equal to 1 μm.

7. The method for preparing ultrafine rhenium powder with low oxygen content according to claim 1, characterized in that: At least one of the following conditions is met: A. The reducing gas includes hydrogen; B. the reduction roasting comprises a first reduction roasting and a second reduction roasting performed sequentially; The temperature of the first reduction roasting is 250°C-300°C, and the time is 2h-4h; The temperature of the second reduction roasting is 600°C-800°C, and the time is 4h-6h; C. The flow rate of the reducing gas during the reduction roasting process is 0.5m 3 / h-1.5m 3 / h.

8. The method for preparing ultrafine rhenium powder with low oxygen content according to any one of claims 1 to 7, characterized in that: At least one of the following conditions is met: A. The vacuum degree of the vacuum environment is greater than 10 -3 Pa; B. The temperature of the deoxidation treatment is 800°C-900°C and the time is 4h-6h.

9. An ultrafine rhenium powder with low oxygen content, characterized in that: The invention is prepared by the method for preparing ultrafine rhenium powder with low oxygen content according to any one of claims 1 to 8.

10. The ultrafine rhenium powder with low oxygen content according to claim 9, characterized in that: The oxygen content is less than or equal to 0.1%, and the particle size is 0.8μm-1.2μm.

Images