Preparation method of high-purity rhenium powder

Abstract

The invention discloses a preparation method of high-purity rhenium powder, and belongs to the field of metal processing.The method prepares a final product through first-stage gradient type high-temperature reduction treatment and second-stage low-temperature reduction treatment.The method is simple in production process, simple in manual operation step, low in production energy consumption, high in crystallinity of the produced product, low in oxygen content and suitable for industrial production. And the purity can reach 4N or above.

Description

Technical Field

[0001] The invention relates to the field of metal processing, and in particular to a method for preparing 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. At present, the preparation process of metal rhenium powder is mainly the reduction method, which uses ammonium rhenate as the raw material, and after pre-treatment such as ball milling and crushing, it is reduced with a reducing agent (usually hydrogen) to prepare the single rhenium powder. However, most of the existing rhenium powder preparation processes have high temperature requirements and high energy consumption. At the same time, the operation steps in the production process are cumbersome, and by-products are easily produced. The oxygen content of the product is high and the purity is low. 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 high-purity rhenium powder, which prepares the final product through a one-stage gradient high-temperature reduction treatment and a two-stage low-temperature reduction treatment. The method has a simple production process and simple manual operation steps. At the same time, the production energy consumption is low, the product has high crystallinity and low oxygen content, and the purity can reach 4N and above.

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

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

[0006] (1) After crushing, the ammonium perrhenate powder is placed in a sintering mold and the filling height is maintained at ≤10 mm, and then a first gradient sintering treatment is performed at 200-300° C. in a hydrogen atmosphere, and then the temperature is raised to 500-600° C. for a second gradient sintering treatment, and finally the temperature is raised to 850-950° C. for a third gradient sintering treatment to obtain a coarse rhenium powder; the flow rate of the hydrogen atmosphere is ≥5 L / min;

[0007] (2) placing the coarse rhenium powder in a sintering mold and maintaining the filling height ≤10 mm, and then performing a secondary sintering treatment at 400-600° C. in a hydrogen atmosphere to obtain the high-purity rhenium powder; the flow rate of the hydrogen atmosphere is ≥5 L / min.

[0008] In order to reduce the difficulty and energy consumption of producing metal rhenium powder and improve the purity of the final product, in the preparation method of the product of the present invention, after the ammonium perrhenate powder is crushed, a sintering treatment is performed in advance in three specific gradient temperature ranges. In this treatment stage, the ammonium perrhenate is fully reduced without experiencing an intermediate idle period, so no intermediate by-products are produced, and the crystallinity of the metal rhenium powder is relatively high; subsequently, in order to further improve the purity of the product and reduce the oxygen content in the product, the obtained coarse rhenium powder needs to be sintered in the second stage at 400-600°C. The setting temperature of the two-stage sintering is low, the overall energy consumption is low, and the temperature range is set with an obvious gradient, the manual operation setting is simple, and the production efficiency is high.

[0009] In the process described above, the temperature range during gradient sintering is very critical. If it is not set properly, the full reduction of the rhenium powder in the first stage and the degree of impurity removal of the rhenium powder in the second stage cannot be guaranteed. At the same time, in the production process, the hydrogen flow rate and the material loading height require specific settings. Otherwise, the purity index of the product may not be fully guaranteed under the low-temperature process and simple operation.

[0010] Preferably, the purity of the ammonium perrhenate is ≥4N.

[0011] The use of high-purity ammonium perrhenate for preparing the product of the present invention can not only avoid the influence of its impurities on the purity of the final product, but also improve the yield of the product and ensure production efficiency.

[0012] Preferably, the average particle size of the ammonium perrhenate powder after crushing is 50-100 μm.

[0013] Preferably, the sintering process in step (1) is carried out in a tube furnace.

[0014] Preferably, the sintering mold is a quartz boat, and the length of the quartz boat is 280-320 mm and the width is 100-150 mm.

[0015] Preferably, in step (1), the first sintering treatment takes 2 to 3 hours, the second sintering treatment takes 2.5 to 3.5 hours, and the third sintering treatment takes 6 to 8 hours.

[0016] More preferably, in step (1), the temperature of the first sintering treatment is 220-280°C and the time is 2.3-2.7 hours, the temperature of the second sintering treatment is 520-580°C and the time is 2.8-3.2 hours, and the temperature of the third sintering treatment is 880-920°C and the time is 6.5-7.5 hours.

[0017] In a single-stage sintering process, in addition to the range setting of the gradient temperature interval, the sintering time in different temperature intervals also needs to be matched accordingly. When the sintering treatment time range under the above preferred range is selected, the single-stage sintering can not only ensure the reduction degree effect of ammonium perrhenate, but also ensure the optimal production efficiency and production energy consumption, thereby improving the production cost performance of the product.

[0018] Preferably, the secondary sintering treatment in step (2) is carried out in a tube furnace.

[0019] Preferably, in step (2), the secondary sintering treatment is performed for 4 to 6 hours.

[0020] More preferably, in the step (2), the temperature during the secondary sintering treatment is 450-550° C. and the time is 4.5-5.5 hours.

[0021] Corresponding to the primary sintering treatment stage, the main function of the secondary sintering treatment is to reduce the content of impurity elements (especially oxygen) in the product. Choosing a suitable sintering time can reduce the sintering energy consumption and hydrogen consumption while ensuring sufficient impurity removal effect of the product.

[0022] Preferably, the flow rate of the hydrogen atmosphere in step (1) and step (2) is 5 to 10 L / min.

[0023] Theoretically, in the preparation process of the high-purity rhenium powder described in the present invention, the higher the flow rate of the hydrogen atmosphere, the better the effect. However, too high a flow rate will not only cause a waste of raw materials, but also cause safety problems. By selecting the hydrogen atmosphere setting at the above preferred flow rate, a balance between raw material consumption and product quality can be taken into account.

[0024] The beneficial effect of the present invention is that the present invention provides a method for preparing high-purity rhenium powder, and the method prepares the final product through a one-stage gradient high-temperature reduction treatment and a two-stage low-temperature reduction treatment. The method has a simple production process and simple manual operation steps. At the same time, the production energy consumption is low, the product has high crystallinity and low oxygen content, and the purity can reach 4N and above.

[0025] Instruction Manual

[0026] Figure 1 This is the XRD spectrum of the product prepared by the method for preparing high-purity rhenium powder of the present invention (the purple one is the comparison standard card). DETAILED DESCRIPTION

[0027] 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.

[0028] Example 1

[0029] An embodiment of a method for preparing high-purity rhenium powder according to the present invention comprises the following steps:

[0030] (1) After crushing 4N purity ammonium perrhenate powder to an average particle size of 75 μm, the powder was placed in a quartz boat with a length of 300 mm and a width of 130 mm and the filling height was kept at about 8 mm. The powder was then placed in a tubular furnace and subjected to a first gradient sintering treatment at 200° C. for 2 h in a hydrogen atmosphere, then heated to 500° C. for a second gradient sintering treatment for 2.5 h, and finally heated to 850° C. for a third gradient sintering treatment for 6 h to obtain a coarse rhenium powder; the flow rate of the hydrogen atmosphere was 10 L / min;

[0031] (2) The crude rhenium powder is placed in a quartz boat of the same size as in step (1) and the filling height is maintained at 8 mm. The boat is then placed in a tubular furnace and subjected to secondary sintering treatment at 400° C. for 4 h in a hydrogen atmosphere to obtain the high-purity rhenium powder. The flow rate of the hydrogen atmosphere is 10 L / min.

[0032] Example 2

[0033] An embodiment of a method for preparing high-purity rhenium powder according to the present invention comprises the following steps:

[0034] (1) After crushing 4N purity ammonium perrhenate powder to an average particle size of 75 μm, the powder was placed in a quartz boat of 300 mm in length and 130 mm in width and the filling height was kept at about 8 mm. The powder was then placed in a tubular furnace and subjected to a first gradient sintering treatment at 250° C. for 2.5 h in a hydrogen atmosphere, then heated to 550° C. for a second gradient sintering treatment for 3 h, and finally heated to 900° C. for a third gradient sintering treatment for 7 h to obtain a coarse rhenium powder; the flow rate of the hydrogen atmosphere was 8 L / min;

[0035] (2) The crude rhenium powder is placed in a quartz boat of the same size as in step (1) and the filling height is maintained at 8 mm. The boat is then placed in a tubular furnace and subjected to secondary sintering treatment at 500° C. for 5 h in a hydrogen atmosphere to obtain the high-purity rhenium powder. The flow rate of the hydrogen atmosphere is 8 L / min.

[0036] Example 3

[0037] An embodiment of a method for preparing high-purity rhenium powder according to the present invention comprises the following steps:

[0038] (1) After crushing 4N purity ammonium perrhenate powder to an average particle size of 75 μm, the powder was placed in a quartz boat with a length of 300 mm and a width of 130 mm and the filling height was kept at about 8 mm. The powder was then placed in a tubular furnace and subjected to a first gradient sintering treatment at 300° C. for 3 h in a hydrogen atmosphere, then heated to 600° C. for a second gradient sintering treatment for 3.5 h, and finally heated to 950° C. for a third gradient sintering treatment for 8 h to obtain a coarse rhenium powder; the flow rate of the hydrogen atmosphere was 5 L / min;

[0039] (2) The crude rhenium powder is placed in a quartz boat of the same size as in step (1) and the filling height is maintained at 8 mm. The boat is then placed in a tubular furnace and subjected to secondary sintering treatment at 600° C. for 6 h in a hydrogen atmosphere to obtain the high-purity rhenium powder. The flow rate of the hydrogen atmosphere is 5 L / min.

[0040] Example 4

[0041] The embodiment of the method for preparing high-purity rhenium powder of the present invention is different from the embodiment 1 only in that the powder filling height of the steps (1) and (2) is 10 mm.

[0042] Example 5

[0043] The embodiment of the method for preparing high-purity rhenium powder of the present invention is different from the embodiment 1 only in that the powder filling height of the steps (1) and (2) is 6 mm.

[0044] Comparative Example 1

[0045] A method for preparing high-purity rhenium powder, the preparation method comprising the following steps:

[0046] (1) After crushing 4N pure ammonium perrhenate powder to an average particle size of 75 μm, the powder was placed in a quartz boat of 300 mm in length and 130 mm in width and the filling height was kept at about 8 mm. The powder was then placed in a tubular furnace and heated to 850° C. in a hydrogen atmosphere for a sintering treatment for 10.5 h to obtain a coarse rhenium powder; the flow rate of the hydrogen atmosphere was 10 L / min;

[0047] (2) The crude rhenium powder is placed in a quartz boat of the same size as in step (1) and the filling height is maintained at 8 mm. The boat is then placed in a tubular furnace and subjected to secondary sintering treatment at 400° C. for 4 h in a hydrogen atmosphere to obtain the high-purity rhenium powder. The flow rate of the hydrogen atmosphere is 10 L / min.

[0048] Comparative Example 2

[0049] A method for preparing high-purity rhenium powder, the preparation method comprising the following steps:

[0050] (1) After crushing 4N purity ammonium perrhenate powder to an average particle size of 75 μm, the powder was placed in a quartz boat with a length of 300 mm and a width of 130 mm and the filling height was kept at about 8 mm. The powder was then placed in a tubular furnace and subjected to a first gradient sintering treatment at 400° C. for 2 h in a hydrogen atmosphere, then heated to 700° C. for a second gradient sintering treatment for 2.5 h, and finally heated to 850° C. for a third gradient sintering treatment for 6 h to obtain a coarse rhenium powder; the flow rate of the hydrogen atmosphere was 10 L / min;

[0051] (2) The crude rhenium powder is placed in a quartz boat of the same size as in step (1) and the filling height is maintained at 8 mm. The boat is then placed in a tubular furnace and subjected to secondary sintering treatment at 400° C. for 4 h in a hydrogen atmosphere to obtain the high-purity rhenium powder. The flow rate of the hydrogen atmosphere is 10 L / min.

[0052] Comparative Example 3

[0053] A method for preparing high-purity rhenium powder, the preparation method comprising the following steps:

[0054] (1) After crushing 4N purity ammonium perrhenate powder to an average particle size of 75 μm, the powder was placed in a quartz boat of 300 mm in length and 130 mm in width and the filling height was kept at about 8 mm. The powder was then placed in a tubular furnace and subjected to a first gradient sintering treatment at 200° C. for 4.5 h in a hydrogen atmosphere, and then heated to 850° C. for a second gradient sintering treatment for 6 h to obtain a coarse rhenium powder; the flow rate of the hydrogen atmosphere was 10 L / min;

[0055] (2) The crude rhenium powder is placed in a quartz boat of the same size as in step (1) and the filling height is maintained at 8 mm. The boat is then placed in a tubular furnace and subjected to secondary sintering treatment at 400° C. for 4 h in a hydrogen atmosphere to obtain the high-purity rhenium powder. The flow rate of the hydrogen atmosphere is 10 L / min.

[0056] Comparative Example 4

[0057] A method for preparing high-purity rhenium powder, the preparation method comprising the following steps:

[0058] (1) After crushing 4N purity ammonium perrhenate powder to an average particle size of 75 μm, the powder was placed in a quartz boat of 300 mm in length and 130 mm in width and the filling height was kept at about 8 mm. The powder was then placed in a tubular furnace and subjected to a first gradient sintering treatment at 200° C. for 2 h in a hydrogen atmosphere, then heated to 500° C. for a second gradient sintering treatment for 2.5 h, and finally heated to 700° C. for a third gradient sintering treatment for 6 h to obtain a coarse rhenium powder; the flow rate of the hydrogen atmosphere was 10 L / min;

[0059] (2) The crude rhenium powder is placed in a quartz boat of the same size as in step (1) and the filling height is maintained at 8 mm. The boat is then placed in a tubular furnace and subjected to secondary sintering treatment at 400° C. for 4 h in a hydrogen atmosphere to obtain the high-purity rhenium powder. The flow rate of the hydrogen atmosphere is 10 L / min.

[0060] Comparative Example 5

[0061] An embodiment of a method for preparing high-purity rhenium powder differs from embodiment 1 only in that the coarse rhenium powder is not subjected to the secondary sintering treatment described in step (2).

[0062] Comparative Example 6

[0063] An embodiment of a method for preparing high-purity rhenium powder is different from embodiment 1 only in that the powder filling height in steps (1) and (2) is 12 mm.

[0064] Comparative Example 7

[0065] An embodiment of a method for preparing high-purity rhenium powder is different from embodiment 1 only in that the flow rate of the hydrogen atmosphere in steps (1) and (2) is 3 L / min.

[0066] Effect Example 1

[0067] In order to verify the quality of the product obtained by the preparation method of 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 (wherein Al to Zn elements are elements required to be checked according to industry standards) 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 detected elements in embodiments 1 to 3 are listed, as shown in Table 1. Other embodiments and comparative examples are not described in detail, and only the total content results are listed, as shown in Table 2. At the same time, the oxygen content in the product was tested by infrared method, as shown in Table 2.

[0068] Table 1

[0069]

[0070]

[0071] Table 2

[0072]

[0073]

[0074] It can be seen from the test results that the preparation methods of each embodiment of the present invention can achieve higher product quality at lower sintering temperature and sintering time, the total content of target detection impurities can be achieved within 41ppm, and the oxygen content can be achieved within 1000ppm, and the product production has high cost performance. Specifically, the process mainly relies on a specific three-stage gradient reduction treatment and a subsequent low-temperature secondary reduction sintering treatment, while controlling the atmosphere flow and filling height of the powder during sintering. If the process conditions are not properly set, the expected effect cannot be achieved, as shown in Comparative Examples 1 to 5, wherein the process described in Comparative Example 1 does not perform a gradient setting during a sintering reduction; although a three-stage gradient interval is set in Comparative Example 2, the interval range is not within the scope of the present invention; Comparative Example 3 sets a suitable gradient interval, but there are only two sections of the program, and the intermediate transition interval sintering program is not set; the temperature during the third gradient sintering treatment in Comparative Example 4 is too low, and the effect of the final product is not ideal. The product described in Comparative Example 5 was not subjected to secondary low-temperature sintering treatment for impurity removal during preparation, and the impurity and oxygen content of the prepared product was relatively high; the filling height of the powder in Comparative Example 6 was too high, resulting in that part of the powder at the bottom could not be fully reduced, and the flow rate of hydrogen as a reducing agent in Comparative Example 7 was too low, and the product could not be completely reduced and impurity removed under such mild sintering conditions.

[0075] The product obtained in Example 1 was subjected to XRD detection. The characteristic peaks of the product in the result spectrum corresponded one to one with the standard card, and the characteristic peaks were sharp, indicating that the product had high crystallinity and high purity.

[0076] 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 high-purity rhenium powder, characterized in that: The following steps are involved: (1) After crushing, the ammonium perrhenate powder is placed in a sintering mold and the filling height is maintained at ≤10 mm, and then a first gradient sintering treatment is performed at 200-300° C. in a hydrogen atmosphere, and then the temperature is raised to 500-600° C. for a second gradient sintering treatment, and finally the temperature is raised to 850-950° C. for a third gradient sintering treatment to obtain a coarse rhenium powder; the flow rate of the hydrogen atmosphere is ≥5 L / min; (2) placing the coarse rhenium powder in a sintering mold and maintaining the filling height ≤10 mm, and then performing a secondary sintering treatment at 400-600° C. in a hydrogen atmosphere to obtain the high-purity rhenium powder; the flow rate of the hydrogen atmosphere is ≥5 L / min.

2. The method for preparing high-purity rhenium powder according to claim 1, characterized in that: The sintering process in the step (1) is carried out in a tubular furnace; the sintering mold is a quartz boat, and the length of the quartz boat is 280 to 320 mm and the width is 100 to 150 mm.

3. The method for preparing high-purity rhenium powder according to claim 1, characterized in that: In the step (1), the first sintering treatment takes 2 to 3 hours, the second sintering treatment takes 2.5 to 3.5 hours, and the third sintering treatment takes 6 to 8 hours.

4. The method for preparing high-purity rhenium powder according to claim 3, characterized in that: In the step (1), the temperature of the first sintering treatment is 220-280°C and the time is 2.3-2.7 hours; the temperature of the second sintering treatment is 520-580°C and the time is 2.8-3.2 hours; the temperature of the third sintering treatment is 880-920°C and the time is 6.5-7.5 hours.

5. The method for preparing high-purity rhenium powder according to claim 1, characterized in that: In the step (2), the secondary sintering process is performed for 4 to 6 hours.

6. The method for preparing high-purity rhenium powder according to claim 5, characterized in that: In the step (2), the temperature during the secondary sintering treatment is 450-550° C. and the time is 4.5-5.5 hours.

7. The method for preparing high-purity rhenium powder according to claim 1, characterized in that: The flow rate of the hydrogen atmosphere in step (1) and step (2) is 5 to 10 L / min.

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