Method and device for directly preparing high-purity rhenium powder from high-purity ammonium rhenate

Abstract

The invention relates to the technical field of preparation of high-purity metal materials, in particular to a method and device for directly preparing high-purity rhenium powder from high-purity ammonium rhenate. The device comprises a reaction furnace, a microwave device arranged at the top of the inner side of the reaction furnace, an ultrasonic device arranged at the bottom of the inner side of the reaction furnace, and multiple layers of shelves arranged in the middle of the inner side of the reaction furnace at intervals up and down; a plurality of pure molybdenum trays with upward openings are arranged on each layer of storage rack; the method is simple, raw material adaptability is high, high-purity ammonium rhenate which is evaporated and crystallized after extraction or ion exchange and contains 99.99% of moisture purity can be directly used as a raw material, the raw material is heated and dried through microwaves, meanwhile, the material is evenly dispersed under the ultrasonic effect, after the material is dried, the material is in full contact with hydrogen under the high-temperature condition for reduction, and the high-purity ammonium rhenate is obtained. The purity of the rhenium powder is larger than 99.99%, the particle size of the rhenium powder is smaller than 100 micrometers, the overall preparation efficiency is improved, the production cost is reduced, and the purity and the particle size of the product are fully guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of high-purity metal material preparation, and in particular to a method and device for directly preparing high-purity rhenium powder from high-purity ammonium rhenate. Background Art

[0002] Metal rhenium and its alloys have a series of excellent properties, and therefore are widely used in industries such as petrochemicals, aerospace, and electronics. In particular, they play an irreplaceable role in certain high-tech fields related to national security and national development strategies.

[0003] At present, the main methods for preparing high-purity rhenium powder include electrolysis, hydrogen reduction, and vapor deposition. Among them, hydrogen reduction is the most commonly used method in industry. The general practice is to evaporate and crystallize the high-purity ammonium rhenate solution prepared by ion exchange or extraction, and then vacuum dry it. Then, the dried material is ball-milled to a certain particle size and screened. It is then loaded into a hydrogen reduction furnace for multi-stage reduction to prepare high-purity rhenium powder. However, this method is greatly affected by the properties of the raw materials. The prepared rhenium powder particles are unevenly distributed, and there are a series of disadvantages such as severe agglomeration, poor fluidity, and low tap density. In addition, the process is long and requires ball milling, screening, and other processes for the material. It is not only time-consuming and labor-intensive, and consumes a large amount of high-purity hydrogen, but also very easy to contact with the outside world during operation, resulting in material contamination, thereby reducing the purity of the product, which greatly affects the performance of related products prepared by the subsequent high-purity rhenium metal. Summary of the invention

[0004] The present invention provides a method and device for directly preparing high-purity rhenium powder from high-purity ammonium rhenate, which overcomes the shortcomings of the above-mentioned prior art and effectively solves the problems of long process flow of preparing high-purity rhenium powder by the existing hydrogen reduction method, which makes the product exposed to the air for a long time, resulting in reduced product purity and uneven particle size of the prepared high-purity rhenium powder.

[0005] To solve the above problems, one of the technical solutions of the present invention is achieved by the following method: A method for directly preparing high-purity rhenium powder from high-purity ammonium rhenate comprises the following steps: The first step: placing the water-containing high-purity ammonium rhenate obtained by evaporating and crystallizing the high-purity ammonium rhenate solution into a pure molybdenum material tray of a reaction furnace; wherein the high-purity ammonium rhenate solution is prepared by an extraction method or an ion exchange method; Step 2: high-purity nitrogen is introduced into the reaction furnace, microwave heating is started, and the water-containing high-purity ammonium rhenate is dried at a temperature of 200°C; Step 3: During the drying process, turn on the ultrasonic function to disperse the dry high-purity ammonium rhenate containing water into tiny particles; Step 4: After the water-containing high-purity ammonium rhenate is fully dried, the temperature of the reactor is raised to 300°C, and hydrogen is introduced to reduce the high-purity ammonium rhenate; Step 5: After the temperature in the reaction furnace rises to 800°C, keep it warm; Step 6: After the heat preservation is completed, nitrogen is introduced to cool down to obtain high-purity rhenium powder.

[0006] In the fourth step above, the equation for the reduction reaction between high-purity ammonium rhenate and hydrogen is: 2NH4ReO4+ H2→ Re2O7+ 4H2O + 2NH3.

[0007] In the fifth step, during the heating process, the heating rate is controlled at 5-10°C / min; the insulation time is 2-3h.

[0008] In the sixth step, after the insulation is completed, when the temperature in the reaction furnace drops to 300° C., nitrogen is introduced to cool the furnace down to a temperature of less than or equal to 50° C., and then the high-purity rhenium powder is taken out.

[0009] The second technical solution of the present invention is achieved in the following way: a device for directly preparing high-purity rhenium powder from high-purity ammonium rhenate, comprising a reactor, a microwave device is provided at the top of the inner side of the reactor, an ultrasonic device is provided at the bottom of the inner side of the reactor, and a multi-layer rack is provided at intervals between the upper and lower parts of the middle of the inner side of the reactor, each layer of the rack is provided with a plurality of pure molybdenum material trays opening upward, and a plurality of vertically penetrating air holes are provided on the upper side of the rack corresponding to the outer side of the pure molybdenum material tray; a gas inlet is provided on the lower side of the outside of the reactor, and a gas outlet is provided on the upper side of the outside of the reactor; a temperature measuring device is installed in the middle of the reactor, a gas flowmeter is installed at the bottom of the reactor, and a control device is provided at the bottom of the reactor, and the control device is connected to the microwave device and the ultrasonic device respectively.

[0010] The control device comprises an ultrasonic control end and a microwave control end, wherein the ultrasonic control end is connected to the ultrasonic device, and the microwave control end is connected to the microwave device.

[0011] The above-mentioned temperature measuring device is a thermocouple.

[0012] The method of the invention is simple and has strong adaptability to raw materials. High-purity ammonium rhenate with a water purity of 99.99% obtained by evaporation and crystallization after extraction or ion exchange can be directly used as a raw material. The raw material is dried by microwave heating, and the material is uniformly dispersed under the action of ultrasound. After the material is dried, the material is fully contacted with hydrogen under high temperature conditions for reduction to generate high-purity ultrafine rhenium powder. The purity of the rhenium powder is greater than 99.99%, and the particle size is less than 100 μm. Conventional vacuum drying and ball milling process are avoided, the overall preparation efficiency is improved, the production cost is reduced, and the purity and particle size of the product are fully guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the device structure of Example 2 of the present invention.

[0015] Figure 2 It is a top view of the storage rack in Example 2 of the present invention.

[0016] In the figure: 1-reaction furnace, 2-microwave device, 3-ultrasonic device, 4-storage rack, 5-pure molybdenum material tray, 6-air vent, 7-gas inlet, 8-gas outlet, 9-temperature measuring device, 10-gas flow meter, 11-ultrasonic control end, 12-microwave control end. DETAILED DESCRIPTION

[0017] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0018] Example 1: The present invention discloses a method for directly preparing high-purity rhenium powder from high-purity ammonium rhenate, comprising the following steps: The first step: placing the water-containing high-purity ammonium rhenate obtained by evaporating and crystallizing the high-purity ammonium rhenate solution into the pure molybdenum material tray 5 of the reaction furnace 1; wherein the high-purity ammonium rhenate solution is prepared by extraction method or ion exchange method.

[0019] Step 2: high-purity nitrogen is introduced into the reaction furnace 1, microwave heating is started, and the high-purity ammonium rhenate containing water is dried at a temperature of 200°C; thus, the air in the reaction furnace 1 is replaced by the introduction of nitrogen, and the high-purity nitrogen is used to protect the high-purity ammonium rhenate containing water from being contaminated and oxidized, while the air and water vapor in the reaction furnace 1 are discharged, and the flow rate of nitrogen is determined by the volume of the reaction furnace 1; microwave heating has the characteristics of fast heating speed and small heat loss, and can quickly heat and dry the moist high-purity ammonium rhenate, thereby shortening the process time.

[0020] Step 3: During the drying process, the ultrasonic function is turned on to disperse the dry high-purity ammonium rhenate containing water into tiny particles; thus, during the reaction process, the high-frequency vibrating ultrasonic wave disperses the high-purity ammonium rhenate into tiny particles, thereby achieving efficient and uniform dispersion of the high-purity ammonium rhenate.

[0021] Step 4: After the high-purity ammonium rhenate containing water is fully dried, the temperature of the reaction furnace 1 is increased to 300° C., and hydrogen is introduced to reduce the high-purity ammonium rhenate; wherein the flow rate of the hydrogen is determined according to the amount of high-purity ammonium rhenate containing water. Due to the effect of ultrasound, the dispersed high-purity ammonium rhenate is fully contacted with the hydrogen, thereby accelerating the reaction speed.

[0022] Step 5: After the temperature in the reaction furnace 1 is raised to 800°C, it is kept warm; during the heating process, the heating rate is controlled to be 5-10°C / min; the insulation time is 2-3h.

[0023] Step 6: After the heat preservation is completed, nitrogen is introduced to cool down to obtain high-purity rhenium powder. After the heat preservation is completed, when the temperature in the reaction furnace 1 drops to 300° C., nitrogen is introduced to cool down to a temperature of less than or equal to 50° C., and then the prepared high-purity rhenium powder is taken out.

[0024] Among them, in the fourth step, the equation for the reduction reaction between high-purity ammonium rhenate and hydrogen is: 2NH4ReO4+ H2→ Re2O7+ 4H2O + 2NH3.

[0025] Example 2: Figure 1 , 2 As shown, an embodiment of the present invention discloses a device for directly preparing high-purity rhenium powder from high-purity ammonium rhenate, comprising a reactor 1, a microwave device 2 is provided on the top of the inner side of the reactor 1, an ultrasonic device 3 is provided on the bottom of the inner side of the reactor 1, and a multi-layer rack 4 is provided at intervals in the middle of the inner side of the reactor 1, and each layer of the rack 4 is provided with a plurality of pure molybdenum material trays 5 opening upward, and a plurality of vertically penetrating vents 6 are provided on the upper side of the rack 4 corresponding to the outer side of the pure molybdenum material tray 5; a gas inlet 7 penetrating inside and outside is provided on the lower side of the outside of the reactor 1, and a gas outlet 8 penetrating inside and outside is provided on the upper side of the outside of the reactor 1; a temperature measuring device 9 is installed in the middle of the reactor 1, a gas flowmeter 10 is installed at the bottom of the reactor 1, and a control device is provided at the bottom of the reactor 1, and the control device is connected to the microwave device 2 and the ultrasonic device 3 respectively.

[0026] The control device includes an ultrasonic control terminal 11 and a microwave control terminal 12, wherein the ultrasonic control terminal 11 is connected to the ultrasonic device 3, and the microwave control terminal 12 is connected to the microwave device 2. Both the ultrasonic control terminal 11 and the microwave control terminal 12 can be switches, and the microwave device 2 and the ultrasonic device 3 can be turned on and off by turning on the corresponding switches.

[0027] The temperature measuring device 9 is a thermocouple as required. When in use, the thermocouple is connected to an external display instrument, and the thermocouple converts the measured temperature signal into an electrical signal, and then outputs it to the display instrument, which processes and converts the received electrical signal and finally displays the corresponding temperature value.

[0028] Embodiment 3: The embodiment of the present invention discloses a method for directly preparing high-purity rhenium powder from high-purity ammonium rhenate. The high-purity ammonium rhenate containing water after extraction or ion exchange evaporation crystallization is placed in the pure molybdenum material tray 5 in the reaction furnace 1. Each pure molybdenum material tray 5 contains about 0.5 kg of ammonium rhenate, which is evenly distributed and has a thickness of about 5 to 6 cm. The furnace door is closed, and high-purity nitrogen is introduced at a flow rate of 3 to 4 L / min. After the nitrogen has completely replaced the controlled ventilation inside the furnace body, microwave heating and ultrasonic functions are started. When the temperature rises to 200°C, it is kept warm for 30 minutes. After the high-purity ammonium rhenate containing water is dried, high-purity hydrogen is introduced when the temperature in the furnace is continued to rise to 300°C. The flow rate of hydrogen is 3 to 4 L / min, and the heating rate is 10°C / min. After the temperature rises to 800°C, it is kept warm for 2 hours. After the insulation is completed, sufficient nitrogen is introduced and the temperature is lowered to below 50°C to take out the high-purity rhenium powder.

[0029] In summary, the method of the present invention is simple and has strong adaptability to raw materials. High-purity ammonium rhenate with a water purity of 99.99% that is evaporated and crystallized after extraction or ion exchange can be directly used as a raw material. The raw material is dried by microwave heating, and the high-purity ammonium rhenate is uniformly dispersed under the action of ultrasound. After the high-purity ammonium rhenate with water is dried, the high-purity ammonium rhenate is fully contacted with hydrogen under high temperature conditions for reduction to generate high-purity ultrafine rhenium powder. The purity of the rhenium powder is greater than 99.99%, and the particle size is less than 100 μm. The conventional vacuum drying and ball milling process is avoided, the overall preparation efficiency is improved, the production cost is reduced, and the purity and particle size of the product are fully guaranteed.

Claims

1. A method for directly preparing high-purity rhenium powder from high-purity ammonium rhenate, characterized in that: The following steps are involved: The first step: placing the water-containing high-purity ammonium rhenate obtained by evaporating and crystallizing the high-purity ammonium rhenate solution into a pure molybdenum material tray of a reaction furnace; wherein the high-purity ammonium rhenate solution is prepared by an extraction method or an ion exchange method; Step 2: high-purity nitrogen is introduced into the reaction furnace, microwave heating is started, and the water-containing high-purity ammonium rhenate is dried at a temperature of 200°C; Step 3: During the drying process, turn on the ultrasonic function to disperse the dry high-purity ammonium rhenate containing water into tiny particles; Step 4: After the water-containing high-purity ammonium rhenate is fully dried, the temperature of the reactor is raised to 300°C, and hydrogen is introduced to reduce the high-purity ammonium rhenate; Step 5: After the temperature in the reaction furnace rises to 800°C, keep it warm; Step 6: After the heat preservation is completed, nitrogen is introduced to cool down to obtain high-purity rhenium powder.

2. The method for directly preparing high-purity rhenium powder from high-purity ammonium rhenate according to claim 1, characterized in that: In the fourth step, the equation for the reduction reaction between high-purity ammonium rhenate and hydrogen is: 2NH4ReO4 + H2 → Re2O7 + 4H2O + 2NH3.

3. The method for directly preparing high-purity rhenium powder from high-purity ammonium rhenate according to claim 1, characterized in that: In the fifth step, during the heating process, the heating rate is controlled to be 5-10°C / min; and the insulation time is 2-3h.

4. The method for directly preparing high-purity rhenium powder from high-purity ammonium rhenate according to claim 1, characterized in that: In the sixth step, after the insulation is completed, when the temperature in the reaction furnace drops to 300° C., nitrogen is introduced to cool the temperature until the temperature is less than or equal to 50° C., and then the high-purity rhenium powder is taken out.

5. A device for directly preparing high-purity rhenium powder from high-purity ammonium rhenate, characterized in that: It includes a reaction furnace, a microwave device is arranged on the top of the inner side of the reaction furnace, an ultrasonic device is arranged on the bottom of the inner side of the reaction furnace, and multiple layers of shelves are arranged at intervals in the middle of the inner side of the reaction furnace, each layer of the shelves is provided with multiple pure molybdenum material trays with openings upward, and the upper side of the shelves corresponding to the outer side of the pure molybdenum material trays is provided with multiple vertically penetrating air holes; a gas inlet is arranged on the lower side of the outside of the reaction furnace, and a gas outlet is arranged on the upper side of the outside of the reaction furnace; a temperature measuring device is installed in the middle of the reaction furnace, a gas flow meter is installed at the bottom of the reaction furnace, and a control device is arranged at the bottom of the reaction furnace, which is respectively connected with the microwave device and the ultrasonic device.

6. The device for directly preparing high-purity rhenium powder from high-purity ammonium rhenate according to claim 5, characterized in that: The control device comprises an ultrasonic control end and a microwave control end, wherein the ultrasonic control end is connected to the ultrasonic device, and the microwave control end is connected to the microwave device.

7. The device for directly preparing high-purity rhenium powder from high-purity ammonium rhenate according to claim 5, characterized in that: The temperature measuring device is a thermocouple.

Images