Preparation method of 4N-grade high-purity rhenium powder

Abstract

The invention discloses a preparation method of 4N-grade high-purity rhenium powder, and belongs to the field of metal processing.According to the method, common 3N-grade ammonium perrhenate serves as a raw material, and after pretreatment, a 4N-grade target product can be obtained through a specific acid pickling mode. The method has the advantages of simple operation steps, low equipment requirement and low dependence on manual operation, and can guarantee the quality stability of the product in the industrial large-scale production process.

Description

Technical Field

[0001] The invention relates to the field of metal processing, and in particular to a method for preparing 4N grade high-purity rhenium powder. Background Art

[0002] Metal rhenium is a rare metal with high melting point, high density, high mechanical strength and high chemical stability. It is widely used in aerospace, military, medical, chemical and other fields. However, the existing methods for preparing metal rhenium powder are mainly hydrogen reduction method or wet method. These two methods have high requirements for raw material quality and equipment, so it is difficult to reduce production difficulty and production cost. Although some laboratory methods have lower production difficulty and cost, the manual operation process is cumbersome and it is difficult to ensure product quality stability. Summary of the invention

[0003] Based on the defects of the prior art, the purpose of the present invention is to provide a method for preparing 4N grade high-purity rhenium powder, which uses common 3N grade ammonium perrhenate as a raw material, and after pretreatment, a 4N grade target product can be obtained by a specific pickling method. The method has simple operation steps, low equipment requirements, low dependence on manual operation, and can ensure product quality stability during industrial-scale production.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for preparing 4N grade high-purity rhenium powder comprises the following steps:

[0006] (1) crushing, hydrogen reduction, ball milling, and passing through a 325-mesh sieve to obtain a coarse rhenium powder; the purity of the ammonium perrhenate is ≥3N;

[0007] (2) placing the crude rhenium powder in an acid solution for pickling treatment, and then washing and drying to obtain the 4N grade high-purity rhenium powder; the mass ratio of the acid solution to the crude rhenium powder is ≥6:1; the solute of the acid solution includes hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is ≥5%, and the mass concentration of hydrofluoric acid is ≥5%; the time of the pickling treatment is ≥6h.

[0008] The existing industrial preparation processes of metal rhenium powder mostly require the use of high-quality raw materials and specially formulated equipment to ensure the purity and stability of the product. However, this type of process production line is difficult to build, has high production costs, and is difficult to expand the production line. On the other hand, some laboratory methods for preparing metal rhenium powder have low production equipment requirements and low production difficulty, but they rely on some manual operation steps (such as multiple soaking, filtering, washing, etc. of the material), resulting in large differences in product quality between different batches, making it difficult to achieve industrial stability. In order to overcome the above technical difficulties, in the technical scheme of the present invention, common and low-priced 3N grade ammonium perrhenate can be used as a raw material for implementation. During implementation, the raw material is subjected to conventional crushing and hydrogen reduction treatment to convert it into elemental rhenium. At this time, the impurity content of the product is relatively high. Compared with the general industrial process that requires secondary hydrogen reduction or impurity removal treatment under specific atmosphere protection conditions, the technical scheme of the present invention directly carries out acid washing treatment on the product with an acid solution of a specific solute and concentration without the aid of special equipment or environment. After a specific period of time, various target metals or non-metallic impurities in the product can be effectively dissolved and separated to obtain a rhenium powder product with a purity of at least 4N grade. At the same time, the method does not need to rely on manual operation, the batch quality stability of the prepared product is high, and the production cost performance is high.

[0009] Preferably, in step (1), the hydrogen reduction is carried out in a tubular furnace, the temperature during the hydrogen reduction is 850-900° C., the time is 6-10 h, and the flow rate of the hydrogen atmosphere is 5-8 L / min.

[0010] The conventional quality ammonium perrhenate of the present invention can be effectively converted into elemental rhenium by hydrogen reduction treatment under the above-mentioned preferred conditions, and the target metal or non-metallic impurities in the product can be effectively removed by a subsequent specific pickling treatment step, and the operating energy consumption and hydrogen consumption are both low.

[0011] Preferably, in step (2), the mass ratio of the acid solution to the coarse rhenium powder is (6-8):1.

[0012] After multiple screenings, the inventors found that when the acid solution configured in the above mass ratio is used to carry out pickling treatment on the crude rhenium powder, the best impurity removal effect can be achieved while keeping the production cost at a low level.

[0013] Preferably, in the acid solution, the mass concentration of hydrogen chloride is 5-10%, and the mass concentration of hydrofluoric acid is 5-10%.

[0014] As the concentration of the solute in the acid solution gradually increases, the impurity removal effect of the coarse rhenium powder is gradually improved. However, after reaching a certain level, the acid solution's effect on dissolving impurities is no longer obvious. Considering the overall effect and cost, the acid solution prepared within the above preferred range is the best.

[0015] Preferably, the mass concentration ratio of the hydrogen chloride to the hydrofluoric acid is (0.7-1.4):1.

[0016] In the acid solution, hydrogen chloride and hydrofluoric acid have different treatment efficiencies for different impurity elements in the crude rhenium powder. The inventors found that when hydrogen chloride and hydrofluoric acid are combined in the above-mentioned proportion, the resulting acid solution can achieve the best impurity removal effect under the conditions described in the present invention.

[0017] Preferably, in step (2), the pickling treatment time is 8 to 12 hours.

[0018] Preferably, in step (2), the washing treatment is carried out with deionized water, and after washing until the conductivity of the obtained supernatant is less than 10 μs / cm, the supernatant is removed by suction filtration.

[0019] Preferably, in step (2), the drying temperature is 80 to 120° C. and the drying time is 3 to 6 hours.

[0020] The beneficial effect of the present invention is that the present invention provides a method for preparing 4N grade high-purity rhenium powder, which uses common 3N grade ammonium perrhenate as a raw material, and after pretreatment, a 4N grade target product can be obtained by a specific pickling method. The method has simple operation steps, low equipment requirements, low dependence on manual operation, and can ensure product quality stability during industrial-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the process for preparing the 4N grade high purity rhenium powder of the present invention. DETAILED DESCRIPTION

[0022] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and comparative examples, the purpose of which is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative work premise belong to the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention, unless otherwise specified, are all commonly used common reagents and instruments.

[0023] Example 1

[0024] An embodiment of a method for preparing a 4N grade high purity rhenium powder according to the present invention, the preparation method is as follows Figure 1 As shown, the following steps are included:

[0025] (1) 100 g of 3N grade ammonium perrhenate was crushed, passed through a 200 mesh sieve, loaded into a quartz boat and placed in a tube furnace, hydrogen was introduced at a flow rate of 6 L / min, and then hydrogen was reduced at 880° C. for 8 h. The obtained powder was ball milled and passed through a 325 mesh sieve to obtain a coarse rhenium powder;

[0026] (2) placing the crude rhenium powder in an acid solution for pickling treatment, then washing it with deionized water for multiple times until the conductivity of the obtained supernatant is less than 10μs / cm, filtering out the supernatant, transferring it to a vacuum drying oven and drying it at 80°C for 6 hours under a vacuum degree of less than -0.1MPa, to obtain the 4N grade high-purity rhenium powder; the mass ratio of the acid solution to the crude rhenium powder is 6:1; the acid solution is an aqueous solution of hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is 10%, and the mass concentration of hydrofluoric acid is 10%; the time of the pickling treatment is 10 hours.

[0027] Example 2

[0028] An embodiment of a method for preparing a 4N grade high-purity rhenium powder according to the present invention comprises the following steps:

[0029] (1) 100 g of 3N grade ammonium perrhenate was crushed, passed through a 200 mesh sieve, loaded into a quartz boat and placed in a tube furnace, hydrogen was introduced at a flow rate of 6 L / min, and then hydrogen was reduced at 880° C. for 8 h. The obtained powder was ball milled and passed through a 325 mesh sieve to obtain a coarse rhenium powder;

[0030] (2) placing the crude rhenium powder in an acid solution for pickling treatment, then washing it with deionized water for multiple times until the conductivity of the obtained supernatant is less than 10μs / cm, filtering out the supernatant, transferring it to a vacuum drying oven and drying it at 100°C for 4 hours under a vacuum degree of less than -0.1MPa, to obtain the 4N grade high-purity rhenium powder; the mass ratio of the acid solution to the crude rhenium powder is 7:1; the acid solution is an aqueous solution of hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is 7%, and the mass concentration of hydrofluoric acid is 7%; the time of the pickling treatment is 12 hours.

[0031] Example 3

[0032] An embodiment of a method for preparing a 4N grade high-purity rhenium powder according to the present invention comprises the following steps:

[0033] (1) 100 g of 3N grade ammonium perrhenate was crushed, passed through a 200 mesh sieve, loaded into a quartz boat and placed in a tube furnace, hydrogen was introduced at a flow rate of 6 L / min, and then hydrogen was reduced at 880° C. for 8 h. The obtained powder was ball milled and passed through a 325 mesh sieve to obtain a coarse rhenium powder;

[0034] (2) placing the crude rhenium powder in an acid solution for pickling treatment, then washing it with deionized water for multiple times until the conductivity of the obtained supernatant is less than 10μs / cm, filtering out the supernatant, transferring it to a vacuum drying oven and drying it at a vacuum degree of less than -0.1MPa and 120°C for 3h to obtain the 4N grade high-purity rhenium powder; the mass ratio of the acid solution to the crude rhenium powder is 8:1; the acid solution is an aqueous solution of hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is 5%, and the mass concentration of hydrofluoric acid is 5%; the time of the pickling treatment is 12h.

[0035] Example 4

[0036] The embodiment of the method for preparing high-purity rhenium powder described in the present invention is different from Example 2 only in that the acid solution is an aqueous solution of hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is 6%, and the mass concentration of hydrofluoric acid is 8%.

[0037] Example 5

[0038] The embodiment of the method for preparing high-purity rhenium powder described in the present invention is different from Example 2 only in that the acid solution is an aqueous solution of hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is 5%, and the mass concentration of hydrofluoric acid is 9%.

[0039] Example 6

[0040] The embodiment of the method for preparing high-purity rhenium powder described in the present invention is different from Example 2 only in that the acid solution is an aqueous solution of hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is 9%, and the mass concentration of hydrofluoric acid is 5%.

[0041] Comparative Example 1

[0042] A method for preparing high-purity rhenium powder, which is different from Example 2 only in that the mass ratio of the acid solution to the coarse rhenium powder is 5:1.

[0043] Comparative Example 2

[0044] A method for preparing high-purity rhenium powder, which is different from Example 2 only in that the pickling treatment time is 5 hours.

[0045] Comparative Example 3

[0046] A method for preparing high-purity rhenium powder, which is different from Example 2 only in that the acid solution is an aqueous solution of hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is 3%, and the mass concentration of hydrofluoric acid is 3%.

[0047] Comparative Example 4

[0048] A method for preparing high-purity rhenium powder, which is different from Example 2 only in that the acid solution is an aqueous solution of hydrogen chloride, and the mass concentration of hydrogen chloride is 14%.

[0049] Comparative Example 5

[0050] A method for preparing high-purity rhenium powder, which is different from Example 2 only in that the acid solution is an aqueous solution of hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is 2%, and the mass concentration of hydrofluoric acid is 12%.

[0051] Comparative Example 6

[0052] A method for preparing high-purity rhenium powder, which is different from Example 2 only in that the acid solution is an aqueous solution of nitric acid and hydrofluoric acid, the mass concentration of the nitric acid is 7%, and the mass concentration of the hydrofluoric acid is 7%.

[0053] Comparative Example 7

[0054] A method for preparing high-purity rhenium powder, which is different from Example 2 only in that the acid solution is an aqueous solution of hydrogen chloride and sulfuric acid, the mass concentration of hydrogen chloride is 7%, and the mass concentration of sulfuric acid is 7%.

[0055] Effect Example 1

[0056] In order to verify the quality of the product obtained by the method for preparing high-purity rhenium powder of the present invention, the products obtained in each embodiment and comparative example were analyzed and tested for the contents of various impurity elements such as Al and As in the product by GDMS method, and the total content of each impurity element was counted. Since the test items are the same, only the test results of all the test elements of Examples 1 to 3 are listed, as shown in Table 1, and other embodiments and comparative examples are not repeated, and only the total content results are listed, as shown in Table 2; at the same time, the yield of each product (based on rhenium in ammonium perrhenate) was counted.

[0057] Table 1

[0058]

[0059]

[0060] Table 2

[0061]

[0062]

[0063] It can be seen from the test results that each embodiment uses common 3N grade ammonium perrhenate as raw material, and only needs simple reduction and pickling treatment to obtain 4N grade rhenium powder products. The content of key impurity elements in the product is low, less than 80ppm, and the yield of the product can reach more than 90%, with high production cost performance.

[0064] In the scheme described in the present invention, the pickling stage is very critical. In addition to affecting its impurity removal efficiency, it will also affect the yield of the product. If the ratio of the acid solution during pickling is too small, or the pickling time is too short, or the concentration of the acid solution used for pickling is too low, as shown in Comparative Examples 1 to 3, not only the content of key impurities in the product will increase, but the yield will also decrease. On the other hand, during acid treatment, the selection and ratio of the acid are also crucial. In the technical scheme of the present invention, based on the characteristics of rhenium powder, a specific combination of hydrogen chloride and hydrofluoric acid is required as the solute. Otherwise, as shown in Comparative Examples 1 to 3, the product will not only have an increased content of key impurities, but also a decreased yield. As shown in Example 4, Comparative Examples 6 and 7, it is difficult to achieve the ideal impurity removal effect by using a single acid solute or other acid solutes for compounding, and the target cannot be reached, and the yield is difficult to follow up. According to Example 2, Examples 4 to 6 and Comparative Example 5, it can be seen that even if hydrogen chloride and hydrofluoric acid are selected as solutes, the concentration ratio of the two needs to be maintained within a certain range, otherwise the expected impurity removal effect cannot be achieved. Among them, when the mass concentration ratio of hydrogen chloride and hydrofluoric acid is preferably (0.7 to 1.4): 1, the impurity content of the product is lower and the quality is better.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing 4N grade high purity rhenium powder, characterized in that: The following steps are involved: (1) crushing, hydrogen reduction, ball milling, and passing through a 325-mesh sieve to obtain a coarse rhenium powder; the purity of the ammonium perrhenate is ≥3N; (2) placing the crude rhenium powder in an acid solution for pickling treatment, and then washing and drying to obtain the 4N grade high-purity rhenium powder; the mass ratio of the acid solution to the crude rhenium powder is ≥6:1; the solute of the acid solution includes hydrogen chloride and hydrofluoric acid, the mass concentration of hydrogen chloride is ≥5%, and the mass concentration of hydrofluoric acid is ≥5%; the time of the pickling treatment is ≥6h.

2. The method for preparing 4N grade high purity rhenium powder according to claim 1, characterized in that: In the step (1), the hydrogen reduction is carried out in a tubular furnace, the temperature of the hydrogen reduction is 850-900° C., the time is 6-10 hours, and the flow rate of the hydrogen atmosphere is 5-8 L / min.

3. The method for preparing 4N grade high purity rhenium powder as claimed in claim 1, characterized in that: In the step (2), the mass ratio of the acid solution to the coarse rhenium powder is (6-8):

1.

4. The method for preparing 4N grade high purity rhenium powder as claimed in claim 1, characterized in that: In the acid solution, the mass concentration of hydrogen chloride is 5-10%, and the mass concentration of hydrofluoric acid is 5-10%.

5. The method for preparing 4N grade high purity rhenium powder as claimed in claim 1, characterized in that: The mass concentration ratio of the hydrogen chloride and the hydrofluoric acid is (0.7-1.4):

1.

6. The method for preparing 4N grade high purity rhenium powder as claimed in claim 1, characterized in that: In the step (2), the pickling treatment time is 8 to 12 hours.

7. The method for preparing 4N grade high purity rhenium powder as claimed in claim 1, characterized in that: In the step (2), the drying temperature is 80 to 120° C. and the drying time is 3 to 6 hours.

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