Preparation device of tantalum powder for capacitor and preparation method of tantalum powder for capacitor

Abstract

The invention discloses a preparation device of tantalum powder for a capacitor, and the preparation device comprises a preparation part which comprises a first cavity, a first temperature regulation and control device for heating the first cavity, a material rack arranged in the first cavity, and a reaction vessel which is arranged on the material rack and is used for preparing the tantalum powder by a magnesium reduction method; the collecting part comprises a body; the collecting container is arranged on the body; the second temperature regulation and control device is used for cooling the collection container; the communication port is communicated with the collection container; a suction member connected to the communication port; the connecting pipeline is connected with the first cavity and the collecting container and is used for enabling the magnesium steam in the first cavity to pass through and enter the collecting container; the heat preservation assembly acts on the connecting pipeline; wherein the collection component is configured in a way that the suction component provides negative pressure enabling the magnesium steam in the first cavity to tend to enter the collection container, the heat preservation component enables the magnesium steam to be subjected to heat preservation when the magnesium steam passes through the connecting pipeline, and the temperature of the collection container is reduced to enable the magnesium steam entering the collection container to be solidified.

Description

Technical Field

[0001] This invention relates to the field of tantalum powder preparation technology, and particularly to an apparatus and method for preparing tantalum powder for capacitors. Background Technology

[0002] Tantalum electrolytic capacitors (hereinafter referred to as tantalum capacitors) have advantages such as high capacitance, small size, strong self-healing ability, and high reliability, and are widely used in high-end technology fields such as communications, computers, automotive electronics, medical devices, radar, aerospace, and automatic control devices. Tantalum powder is the key material for making tantalum capacitors; only by using capacitor-grade tantalum powder with higher voltage withstand performance can tantalum capacitors with better reliability be produced. Therefore, only by continuously developing capacitor-grade tantalum powder with higher voltage withstand performance can the produced tantalum capacitors continuously meet the high reliability requirements of electronic devices and electronic circuits.

[0003] Currently, the main industrial methods for preparing capacitor-grade tantalum powder include the sodium reduction of potassium fluorotantalate, the magnesium reduction of tantalum oxide, and the tantalum ingot hydrogenation method. Among these, the sodium reduction of potassium fluorotantalate and the tantalum ingot hydrogenation methods produce tantalum powder with excellent voltage withstand properties, but a relatively low specific capacitance. The magnesium reduction of tantalum oxide method, by altering the state of the reactants, is advantageous for producing capacitor-grade tantalum powder with improved specific capacitance and voltage withstand properties. However, this method typically involves using an excess of magnesium as a reducing agent to reduce tantalum oxide, which can negatively impact the physicochemical properties of the tantalum powder, such as its oxygen and magnesium content. Summary of the Invention

[0004] The purpose of this invention is to provide an apparatus and a method for preparing tantalum powder for capacitors that can produce higher quality tantalum powder.

[0005] The first aspect of this invention discloses an apparatus for preparing tantalum powder for capacitors, comprising:

[0006] The preparation component includes a first cavity, a first temperature control device for heating the first cavity, a material rack placed inside the first cavity, and a reactor dish for preparing tantalum powder by magnesium reduction placed on the material rack.

[0007] Collection components, including:

[0008] ontology;

[0009] A collection container is provided on the main body;

[0010] A second temperature control device is used to cool the collection container;

[0011] A connection port is provided, which connects to the collection container.

[0012] A suction component is connected to the communication port;

[0013] A connecting pipe is provided to connect the first chamber and the collection container, allowing magnesium vapor in the first chamber to pass through and enter the collection container;

[0014] Thermal insulation components are used in the connecting pipes;

[0015] The collecting component is configured such that the suction component provides a negative pressure that causes the magnesium vapor in the first chamber to tend to enter the collecting container, the heat preservation component keeps the magnesium vapor warm as it passes through the connecting pipe, and the temperature of the collecting container is reduced to such that the magnesium vapor entering the collecting container condenses.

[0016] In some embodiments, the connecting pipe includes a U-shaped pipe section located above the first cavity and the collection container. The U-shaped pipe section includes a first longitudinal pipe connected to the first cavity, a second longitudinal pipe connected to the collection container, and a transverse pipe connecting the first longitudinal pipe and the second longitudinal pipe. The insulation assembly includes a heating device for heating the transverse pipe arranged along the extension direction of the transverse pipe and an insulation layer covering the first longitudinal pipe and the second longitudinal pipe.

[0017] In some embodiments, the connecting pipe further includes a first on-off valve disposed on the first longitudinal pipe for controlling the on-off state of the first longitudinal pipe and a second on-off valve disposed on the second longitudinal pipe for controlling the on-off state of the second longitudinal pipe.

[0018] In some embodiments, the collection component further includes a pressure detection device for detecting the pressure of gas passing through the connecting pipe.

[0019] In some embodiments, the body further includes a second cavity in which the collection container is detachably disposed.

[0020] In some embodiments, the second temperature control device includes a water-cooled pipe and / or an external spray system disposed on the main body, wherein the water-cooled pipe is used to introduce cooling water, and the external spray system is used to spray cooling water onto the main body.

[0021] In some embodiments, the fabrication component further includes an insulated top cover for sealing the first cavity, and the connecting pipe extends into the top of the first cavity after passing through the insulated top cover.

[0022] In some embodiments, the fabrication component further includes a temperature measuring device disposed at the top of the first cavity and configured to detect the temperature of the first cavity.

[0023] In some embodiments, the collection container is made of a nickel-based alloy material.

[0024] A second aspect of this invention discloses a method for preparing tantalum powder for capacitors, using any of the aforementioned apparatus for preparing tantalum powder for capacitors, the method comprising:

[0025] Step a: The material for preparing tantalum powder is placed in the reactor vessel located in the first chamber, and the first temperature control device is used to heat the first chamber to cause the material to undergo a reduction reaction to prepare tantalum powder; the material includes tantalum oxide and magnesium powder;

[0026] Step b: After the material reduction reaction is completed, the temperature of the collection container is maintained below the condensation temperature of magnesium vapor using the second temperature control device, and the magnesium vapor in the first chamber is collected into the collection container by the collection component.

[0027] In some embodiments, step b further includes: after the material reduction reaction is completed, the temperature of the first chamber is changed to 650°C~850°C, and then the magnesium vapor in the first chamber is collected in the collection container.

[0028] In some embodiments, step b further includes: using the suction component to generate negative pressure on the communication port, and controlling the collection time of the collecting component for collecting magnesium vapor to be 3h~20h.

[0029] In some embodiments, the suction component generates a negative pressure of -0.1MPa to -0.05MPa on the communication port.

[0030] The apparatus for preparing tantalum powder for capacitors provided by this invention organically integrates the preparation and collection components through connecting pipes and suction components. Magnesium vapor is promptly removed from the reaction zone (first chamber) via negative pressure suction, and a heat-insulating component maintains the temperature of the connecting pipe, preventing premature condensation of magnesium vapor during transport due to temperature drop. This effectively avoids pipe blockage and ensures continuous unobstructed airflow. This allows magnesium vapor to be immediately and directionally transported to the collection container for condensation and recovery after the magnesium reduction of tantalum oxide reaction. This significantly improves the magnesium recovery rate and can substantially reduce the magnesium content in the final tantalum powder product, thereby improving the purity and performance stability of the tantalum powder and better meeting the requirements for tantalum powder used in capacitors.

[0031] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0032] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0033] Figure 1 This is a schematic diagram of the structure of some embodiments of the apparatus for preparing tantalum powder for capacitors disclosed herein.

[0034] Figure 2 The morphology diagram of tantalum powder formed by the apparatus for preparing tantalum powder for capacitors disclosed herein is shown. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0037] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0040] In the process of reducing tantalum oxide with magnesium to prepare tantalum powder, a large amount of magnesium is required as a reducing agent, typically 1.1 to 5 times the theoretically required amount. Therefore, a large amount of unreacted magnesium remains after the reaction. In industrial production, this excess magnesium is subjected to subsequent acid washing along with the raw tantalum powder and the byproduct magnesium oxide. Pure water and inorganic acids (preferably hydrochloric acid, nitric acid, sulfuric acid, hydrogen peroxide, or one or more of these) are added. The excess magnesium reacts violently with the inorganic acid, releasing a large amount of heat, causing the material to boil and spray. This not only results in significant material loss but also poses safety hazards to operators. Therefore, if this excess magnesium is not effectively collected and treated, it will not only waste resources and increase production costs but also lead to higher levels of impurities such as magnesium and oxygen in the final tantalum powder product, affecting product purity and electrochemical performance.

[0041] To address the technical problem of the difficulty in effectively collecting excess metallic magnesium during the magnesium reduction of tantalum oxide, which affects the performance of tantalum powder and production safety, the apparatus for preparing tantalum powder for capacitors in this embodiment includes a preparation component 1 and a collection component 2.

[0042] like Figure 1As shown, the preparation component 1 includes a first chamber 11, a first temperature control device 12 for heating the first chamber 11, a material rack 13 placed inside the first chamber 11, and a reactor vessel placed on the material rack 13 for preparing tantalum powder by magnesium reduction. The preparation component 1 is used to complete the core reaction of magnesium reducing tantalum oxide to generate tantalum powder. The preparation component 1 includes a sealed first chamber 11, which is typically a furnace body or reaction vessel made of high-temperature resistant materials (such as stainless steel, special alloys, or a steel shell lined with refractory bricks). The material rack 13 is provided inside the first chamber 11 for supporting one or more reactor vessels. The reactor vessel is used to hold the reactants, i.e., a mixture of tantalum oxide, diluent, and excess magnesium powder. Its material must be able to withstand high temperatures and not react with the reactants; for example, tantalum, nickel-based alloys, or corundum crucibles can be used. The first temperature control device 12 is used to heat the first chamber 11 to start and maintain the high-temperature environment required for the reduction reaction. The first temperature control device 12 can be a resistance heating wire or heating rod arranged around the wall of the first cavity 11, or an induction coil disposed inside the first cavity 11, or an external gas or fuel heating system. Its function is to raise the temperature inside the first cavity 11, for example, to and maintain it at the temperature required for the reduction reaction, such as 800°C to 1000°C.

[0043] The collecting component 2 includes a body 21, a collecting container 22, a second temperature control device 23, a connecting port 24, a suction component, a connecting pipe 25, and a heat insulation component 26. The collecting container 22 is mounted on the body 21; the second temperature control device 23 is used to cool the collecting container 22; the connecting port 24 is connected to the collecting container 22; the suction component is connected to the connecting port 24; the connecting pipe 25 connects the first chamber 11 and the collecting container 22, allowing magnesium vapor in the first chamber 11 to pass through and enter the collecting container 22; the heat insulation component 26 acts on the connecting pipe 25.

[0044] The collecting component 2 is configured such that the suction component provides a negative pressure that causes the magnesium vapor in the first chamber 11 to tend to enter the collecting container 22, the heat preservation component 26 keeps the magnesium vapor warm when it passes through the connecting pipe 25, and the temperature of the collecting container 22 is reduced to the point that the magnesium vapor entering the collecting container 22 condenses.

[0045] The main body 21 constitutes the main frame and support structure of the collecting component 2. The collecting container 22 is disposed on or within the main body 21 and is used to receive and condense magnesium vapor, causing it to solidify into solid magnesium. The collecting container 22 is connected to the outside via a connecting port 24. A suction component, such as a vacuum pump, is connected to the connecting port 24, and when operating, it generates and maintains a certain negative pressure (vacuum) within the collecting container 22 and in the connecting pipe 25 connected to it.

[0046] The connecting pipe 25 is a channel connecting the internal space of the first chamber 11 and the internal space of the collection container 22. One end of it extends into the first chamber 11 (preferably to the top space of the first chamber 11), and the other end is connected to the collection container 22. Magnesium vapor will be drawn from the first chamber 11 to the collection container 22 through this connecting pipe 25 under the negative pressure generated by the suction component.

[0047] The insulation component 26 is a key component acting on the connecting pipe 25. Its function is to insulate or heat the connecting pipe 25 during magnesium vapor transportation to prevent the magnesium vapor from condensing midway due to excessively low pipe wall temperature. Magnesium has a freezing point of approximately 650℃; if the vapor condenses in the pipe, magnesium particles will accumulate, eventually causing pipe blockage and interrupting the recovery operation. The insulation component 26 can be an electric heating tape or a wound heating wire for heating the pipe, or it can be insulation materials such as insulation cotton or aluminum silicate fiber blankets wrapped around the pipe, or a combination of both.

[0048] The second temperature control device 23 is used to force-cool the collection container 22. Its function is to reduce the temperature of the wall surface and internal space of the collection container 22 to below the freezing point of magnesium (approximately 650°C), preferably below 200°C or even near room temperature. When high-temperature magnesium vapor enters the cooled collection container 22, it rapidly loses heat, condenses, and solidifies, thus being effectively captured and recovered. The second temperature control device 23 can be a water-cooled jacket or coil installed around the collection container 22 or inside the main body 21, or it can be an external spray system that sprays cooling water onto the outer wall of the collection container 22.

[0049] When the collecting component 2 is operating, the suction component is activated, creating a directional airflow (flowing towards the collecting container 22) in the collecting container 22 and the connecting pipe 25. Simultaneously, the insulation component 26 operates, ensuring that the temperature inside the connecting pipe 25 is higher than the freezing point of magnesium. The second temperature control device 23 operates, creating a low-temperature zone inside the collecting container 22. Thus, magnesium vapor in the first chamber 11 flows into the connecting pipe 25 under pressure difference, maintaining its gaseous state under insulation and being smoothly transported to the collecting container 22, where it rapidly condenses and solidifies at low temperature. This embodiment ensures the continuity, efficiency, and reliability of magnesium vapor recovery.

[0050] The apparatus for preparing tantalum powder for capacitors in this embodiment organically integrates the preparation component 1 and the collection component 2 through a connecting pipe 25 and a suction component. Magnesium vapor is promptly removed from the reaction zone (first chamber 11) via negative pressure suction. A heat-insulating component 26 acts on the connecting pipe 25 to maintain its temperature, preventing premature condensation of magnesium vapor during transport due to temperature drop. This effectively avoids pipe blockage and ensures continuous unobstructed airflow. This allows magnesium vapor to be immediately and directionally transported to the collection container 22 for condensation and recovery after the magnesium reduction of tantalum oxide reaction. This significantly improves the magnesium recovery rate, substantially reduces the magnesium content in the final tantalum powder product, thereby improving the purity and performance stability of the tantalum powder and better meeting the requirements for tantalum powder used in capacitors.

[0051] In some embodiments, such as Figure 1 As shown, the connecting pipe 25 includes a U-shaped pipe section located above the first cavity 11 and the collection container 22. The U-shaped pipe section includes a first longitudinal pipe 251 connected to the first cavity 11, a second longitudinal pipe 252 connected to the collection container 22, and a transverse pipe 253 connecting the first longitudinal pipe 251 and the second longitudinal pipe 252. The insulation component 26 includes a heating device 261 arranged along the extension direction of the transverse pipe 253 for heating the transverse pipe 253, and an insulation layer covering the first longitudinal pipe 251 and the second longitudinal pipe 252. In this embodiment, the U-shaped pipe section design, due to the relatively long transverse pipe 253, facilitates the arrangement of the heating device 261 to control the temperature of the transverse pipe. Since the first longitudinal pipe 251 and the second longitudinal pipe 252 are relatively short, it is more suitable to use an insulation layer for insulation. The heating device 261 can be, for example, an electric heating strip, a heating rope, or an induction coil tightly fitted or wrapped around the outer wall of the transverse pipe 253. The heating device 261 actively heats the horizontal pipe 253, ensuring that the temperature of this horizontal section, especially the highest point, remains above the condensation temperature of magnesium vapor, effectively preventing pipe blockage. The insulation layer can be made of high-temperature resistant ceramic fiber wool, rock wool, glass wool, or other materials. Its function is to passively insulate the two longitudinal pipes, reducing heat loss to the environment. This helps maintain the pipe's internal temperature, improves energy efficiency, and enhances the working environment. This combination of "active horizontal heating + passive vertical insulation" optimizes energy consumption while ensuring effective anti-blocking.

[0052] In some embodiments, such as Figure 1As shown, the connecting pipe 25 also includes a first on / off valve 256 on the first longitudinal pipe 251 for controlling the on / off of the first longitudinal pipe 251, and a second on / off valve 257 on the second longitudinal pipe 252 for controlling the on / off of the second longitudinal pipe 252. The first on / off valve 256 and the second on / off valve 257 can be high-temperature resistant ball valves. In this embodiment, by setting the first on / off valve 256 and the second on / off valve 257, when the magnesium reduction of tantalum oxide reaction is in progress but has not yet entered the magnesium recovery stage, the first on / off valve 256 can be closed to completely isolate the preparation component 1 from the collection component 2, avoiding mutual interference of the reaction atmosphere. When it is necessary to repair the collection component 2 or replace the collection container 22, the first on / off valve 256 can be closed first, and after the residual magnesium vapor in the pipe has been treated, the second on / off valve 257 can be closed, allowing for safe operation.

[0053] In some embodiments, the collection component 2 further includes a pressure detection device 27 for detecting the pressure of the gas passing through the connecting pipe 25. The pressure detection device 27 can be installed on the connecting pipe 25 (e.g., on a horizontal pipe 253) and is used to monitor the pressure within the connecting pipe 25 in real time. Operators can use the pressure readings to determine the operating status of the suction component, whether the pipe is clear (if blocked, the pressure will be abnormal), and the progress of the recovery process (the system pressure may change as magnesium vapor is extracted). The pressure detection device 27 provides real-time parameters, making the entire recovery process more controllable and intelligent.

[0054] In some embodiments, the main body 21 further includes a second cavity, in which the collection container 22 is detachably disposed. The second cavity may be a blind hole structure recessed downwards from the top of the main body, and the collection container 22 may be designed as a cylindrical, box-shaped, or specific-shaped structure. In this embodiment, after the magnesium vapor recovery is completed and solid magnesium has condensed inside the collection container 22, the entire collection container 22 can be easily removed from the second cavity and transported to a designated area for magnesium recovery and utilization. This embodiment facilitates the installation and retrieval of the collection container.

[0055] In some embodiments, as shown in the figure, the second temperature control device 23 includes a water-cooled pipe and / or an external spray system disposed on the body 21. The water-cooled pipe is used to introduce cooling water, and the external spray system is used to spray cooling water onto the body 21. The water-cooled pipe forms a water-cooled jacket or coil inside the body 21 or around the outer wall of the collection container 22. During operation, cooling water (such as circulating cooling water) is continuously introduced into the pipe. Through heat exchange between the water and the metal wall, the heat of the collection container 22 is continuously carried away, achieving rapid and uniform cooling with high cooling efficiency and stable temperature control. The external spray system can be, for example, an array of nozzles arranged above or around the body 21. During operation, the nozzles spray cooling water onto the outer wall of the collection container 22 and / or relevant parts of the body 21, utilizing water evaporation heat absorption and direct heat exchange for cooling. This method has a simple structure, high cooling intensity, and can achieve rapid and efficient cooling. In this embodiment, the water-cooled pipe and the external spray system can be used in combination. For example, in the early stages of the recycling operation, basic temperature control is mainly achieved through water-cooled pipes. When a large amount of magnesium vapor enters and enhanced condensation is required, an external spray system is activated to provide auxiliary enhanced cooling.

[0056] The second temperature control device 23 in this embodiment can ensure that the inner wall of the collection container 22 is always at a low temperature, so that the incoming magnesium vapor will condense instantly, thereby improving the recovery speed and recovery rate.

[0057] In some embodiments, as shown in the figure, the preparation component 1 further includes an insulated top cover 14 for sealing the first cavity 11, and a connecting pipe 25 extends into the top of the first cavity 11 after passing through the insulated top cover 14. The insulated top cover 14 may be made of a high-temperature resistant material and filled with insulation material. After passing through the sealing interface on the insulated top cover 14, the connecting pipe 25 extends downward into the top space of the first cavity 11. The insulated top cover 14 can form a sealed reaction space with the first cavity 11, preventing air from entering and causing material oxidation, and maintaining the inert or reducing atmosphere (such as argon protection) required for the reaction, while reducing heat loss from the top of the first cavity 11, improving heating efficiency, and ensuring uniform temperature in the reaction zone.

[0058] In some embodiments, the preparation component 1 further includes a temperature measuring device 15, which is disposed at the top of the first cavity 11 and configured to detect the temperature of the first cavity 11. The temperature measuring device in this embodiment can be a thermocouple or an infrared thermometer, etc. Preferably, the temperature measuring device 15 is disposed at the top of the first cavity 11 and extends into the cavity to a certain depth. It is configured to detect the temperature inside the first cavity 11 in real time, and because it is arranged at the top of the first cavity, it can more accurately detect and react to the temperature of magnesium vapor, achieving efficient recovery of magnesium vapor.

[0059] In some embodiments, the collection container 22 is made of a nickel-based alloy. The collection container 22 needs to undergo repeated high-temperature magnesium vapor impacts followed by forced cooling to low temperatures, and may come into contact with condensed magnesium; therefore, its material needs to possess excellent overall performance. Thus, preferably, the collection container 22 is made of a nickel-based alloy. Using a nickel-based alloy to manufacture the collection container 22 can significantly extend its service life, reduce the frequency of maintenance and replacement, ensure the long-term stable operation of the recycling system, and avoid the introduction of additional impurities due to container material issues.

[0060] In some embodiments, a method for preparing tantalum powder for capacitors is also disclosed, using any of the above-described apparatus for preparing tantalum powder for capacitors. The method for preparing tantalum powder for capacitors includes:

[0061] Step a: The material for preparing tantalum powder is placed in a reactor dish located in the first chamber 11, and the first temperature control device 12 is used to heat the first chamber 11 to carry out a reduction reaction of the material to prepare tantalum powder; the material includes tantalum oxide and magnesium powder.

[0062] Step b: After the material reduction reaction is completed, the temperature of the collection container 22 is maintained below the condensation temperature of magnesium vapor using the second temperature control device 23, and the magnesium vapor in the first chamber 11 is collected into the collection container 22 by the collection component 2.

[0063] In some embodiments, step b further includes: after the material reduction reaction is completed, the temperature of the first chamber 11 is changed to 650°C~850°C, and then the magnesium vapor in the first chamber 11 is collected in the collection container 22.

[0064] Table 1. Vapor pressure of magnesium metal as a function of temperature

[0065] According to the table above, magnesium has a relatively high vapor pressure between 650 and 1000°C, which is suitable for evacuation and removal of magnesium. However, since the vapor pressure is high at 850°C, evacuation and removal of magnesium at temperatures above 850°C can easily cause tantalum powder to spray out and block the evacuation pipe. Therefore, the temperature setting in this embodiment can ensure the effective formation of magnesium vapor and also protect the tantalum powder and the pipe.

[0066] In some embodiments, step b further includes: using a suction component to generate negative pressure on the connecting port 24, and controlling the collection time of the collecting component 2 for magnesium vapor to be 3h~20h. Optionally, the suction component is configured to generate negative pressure on the connecting port 24 for 3h, 5h, 10h, 15h, or 20h. In the above embodiments, after the magnesium reduction tantalum oxide reaction is completed, it continues to volatilize at high temperature to form magnesium vapor. By applying negative pressure with the suction component, the magnesium vapor is continuously drawn into the collecting container for condensation and collection. If the evacuation time is too short (less than 3h), the residual magnesium vapor cannot be fully discharged, resulting in some excess magnesium remaining in the reaction zone or adhering to the surface of the tantalum powder, causing an increase in the content of magnesium and oxygen impurities in the final product, affecting the purity and electrochemical performance of the tantalum powder; it may also increase the safety risks of subsequent processing due to magnesium residue. If the evacuation time is too long (more than 20h), it will prolong the production cycle, reduce equipment turnover efficiency, and is not conducive to large-scale continuous production. Therefore, controlling the evacuation and magnesium removal time within the range of 3 to 20 hours achieves a good balance between magnesium removal efficiency, product purity, production efficiency, and process safety. Within this time frame, excess magnesium in reaction vessel 1 can be effectively and completely removed in vapor form, significantly reducing the magnesium and oxygen content in tantalum powder and improving product quality.

[0067] In some embodiments, the suction component generates a negative pressure of -0.1 MPa to -0.05 MPa at the connection port 24. In this embodiment, controlling the evacuation pressure of the suction component at -0.1 MPa to -0.05 MPa enables the collection container to form a stable vacuum environment, promoting the continuous volatilization and directional flow of residual metallic magnesium under high temperature conditions. This negative pressure environment effectively enhances the airflow driving force, allowing magnesium vapor to migrate quickly and completely from the reaction zone to the cooling zone of the collection container, preventing it from condensing and flowing back in the reaction zone or adhering to the surface of the tantalum powder product. If the evacuation pressure is too high (i.e., insufficient vacuum, such as greater than -0.05 MPa), the diffusion of magnesium vapor is hindered, the migration rate decreases, resulting in insufficient magnesium removal and affecting the final purity of the tantalum powder and the magnesium removal rate. If the evacuation pressure is too low (i.e., excessively high vacuum, such as below -0.1 MPa), it increases the difficulty of system sealing and the risk of leakage, and may also cause fine particles such as tantalum powder to be carried into the collector 2 by the strong airflow. Therefore, setting the evacuation pressure within the range of -0.1MPa to -0.05MPa can not only efficiently remove excess magnesium and significantly reduce the content of magnesium and oxygen impurities in tantalum powder, thereby improving the chemical stability and electrochemical performance of the product, but also enhance process controllability, making it suitable for continuous industrial production and conducive to the stable preparation of high-quality tantalum powder.

[0068] The following is combined Figure 1 A method for preparing tantalum powder for capacitors is given.

[0069] (1) Mix tantalum oxide, diluent and magnesium powder, which is 1.1 to 5 times the theoretical amount required to reduce tantalum oxide to tantalum powder, and place them in a tantalum crucible on the material rack 13. First, evacuate the first chamber and replace it with inert argon gas, then heat it to 800-1000℃ and keep it at that temperature for 1-5 hours to carry out high-temperature reduction.

[0070] (2) After the material reduction reaction is completed, the material temperature is reduced to 650℃-850℃. The magnesium vapor in the first chamber 11 is extracted by the vacuum pump through the connecting pipe 25 on the heat-insulating top cover 14 of the first chamber for 3-15 hours, so that the magnesium vapor rises and continues to condense into the condensation zone of the collection container 22.

[0071] (3) After all magnesium is removed, the material in the first chamber 11 is cooled to room temperature and passivated.

[0072] (4) The material is discharged from the furnace, washed with water, pickled and dried to obtain tantalum powder raw powder;

[0073] (5) Select 2 to 3 of the following processes for the tantalum powder raw powder: molten salt assisted heat treatment, high temperature heat treatment, deoxidation, etc.

[0074] (6) Perform the necessary water washing, acid washing, drying and powdering steps according to the process selected in (5) to obtain the final tantalum powder product. The morphology of the tantalum powder is as follows: Figure 2 As shown, the porosity is good, and the particle uniformity is good, with no excessively large particles.

[0075] (7) Finally, the magnesium reducing agent crystals collected in the collection container 22 are cleaned and collected, or they can be cleaned periodically according to the amount collected.

[0076] By using the preparation apparatus and method of this disclosure, the prepared tantalum powder has good performance, low oxygen content, low magnesium content, and excess magnesium is recovered, allowing for resource reuse.

[0077] The following are specific examples and comparative examples to illustrate the electrical performance data of the prepared tantalum powder.

[0078] Example:

[0079] Mix 50.0 kg of tantalum oxide (Ta2O5), diluent, and 40.5 kg of magnesium powder (theoretically, 13.5 kg of magnesium is needed to completely remove oxygen from tantalum oxide, so the excess magnesium weight is 27 kg). Place the mixture in the reactor vessel of the material rack 13. Seal the first chamber 11 with the heat-insulating top cover 14 using fasteners. Evacuate and replace the gas in the first chamber 11, and fill it with inert argon gas. During the heating process, maintain the pressure in the first chamber 11 at 0.1-0.15 MPa. Heat to 920℃ and hold for 3 hours to allow the reduction reaction to occur fully.

[0080] After the reduction reaction is complete, the temperature is lowered to 750℃. The excess magnesium vapor in the first chamber 11 still has a high vapor pressure. The excess magnesium vapor is then evacuated through the connecting pipe 25 using a suction system to the condensation zone of the collection container 22, where it cools and forms solid magnesium crystals. After evacuation for 15 hours via the connecting pipe 25, all the excess magnesium is collected. The material in the first chamber 11 is then cooled to room temperature for passivation treatment.

[0081] Next, the material in the first chamber 11 was subjected to acid washing to separate tantalum powder, which was then dried and sieved to obtain raw tantalum powder. The collected tantalum powder weighed 40 kg, with an oxygen content of 3800 ppm, a magnesium content of 9 ppm, and 25.65 kg of magnesium. During the acid washing process, no large amount of heat was generated, preventing material spraying and avoiding potential hazards to personnel and material loss. The raw tantalum powder underwent subsequent high-temperature heat treatment and oxygen reduction processes to obtain the final tantalum powder product. The final tantalum powder product's electrical properties were significantly better than the comparative example, as shown in Table 2.

[0082] Comparative example:

[0083] 50.0 kg of tantalum oxide (Ta2O5), diluent, and 40.5 kg of magnesium powder (theoretically, 13.5 kg of magnesium is needed to completely remove oxygen from tantalum oxide, so the excess magnesium weight is 27.0 kg) are mixed evenly and placed in a material rack. Then, the gas in the reaction vessel is evacuated and replaced, and inert argon gas is introduced. During the heating process, the pressure in the reaction vessel is maintained at 0.1-0.15 MPa. The temperature is raised to 920℃ and held for 3 hours. Then, the temperature is lowered to 750℃, and the excess magnesium is evacuated to remove it. At this time, the excess magnesium vapor in the reaction vessel still has a high vapor pressure. The evacuation is carried out for 15 hours, and the material in the reaction vessel is cooled to room temperature for passivation treatment.

[0084] Upon opening the reaction vessel, a large amount of residual magnesium was found in the material and even on the crucible lid. Because the large amount of magnesium inside the reaction vessel could not be completely removed, although suction was attempted, the high temperature inside the vessel prevented timely condensation of the magnesium vapor, causing it to swirl internally. Furthermore, the lack of a magnesium collector meant that the condensed magnesium vapor flowed back onto the material and the material rack. Next, the material in the reaction vessel was subjected to acid washing to separate tantalum powder. During the acid washing process, a large amount of heat was generated, causing the material to boil and spray, posing a safety hazard and resulting in significant material loss. After drying and sieving, raw tantalum powder was obtained, of which 12 kg (a significant loss) was collected, with an oxygen content of 10500 ppm and a magnesium content of 35 ppm. 3.5 kg of magnesium was collected (a large amount could not be collected). Due to the significant loss of raw tantalum powder and the high impurity content, the final tantalum powder product produced in subsequent processes had poor performance (see Table 2). Additionally, 27.0 kg of excess magnesium powder was recovered, with only a small portion being recycled, resulting in resource waste.

[0085] Table 2 Electrical performance data of finished tantalum powder

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. An apparatus for preparing tantalum powder for capacitors, characterized in that, include: The preparation component (1) includes a first chamber (11), a first temperature control device (12) for heating the first chamber (11), a material rack (13) placed in the first chamber (11), and a reactor dish for preparing tantalum powder by magnesium reduction placed on the material rack (13); The collecting component (2) includes: a body (21); a collecting container (22) disposed on the body (21); a second temperature control device (23) for cooling the collecting container (22); a connecting port (24) connected to the collecting container (22); a suction component connected to the connecting port (24); a connecting pipe (25) connecting the first chamber (11) and the collecting container (22) for allowing magnesium vapor in the first chamber (11) to pass through and enter the collecting container (22); and a heat-insulating component (26) acting on the connecting pipe (25). The collecting component (2) is configured such that the suction component provides a negative pressure that causes the magnesium vapor in the first chamber (11) to tend to enter the collecting container (22), the heat-insulating component (26) keeps the magnesium vapor warm when it passes through the connecting pipe (25), and the temperature of the collecting container (22) is reduced to the point that the magnesium vapor entering the collecting container (22) condenses.

2. The apparatus for preparing tantalum powder for capacitors as described in claim 1, characterized in that, The connecting pipe (25) includes a U-shaped pipe section located above the first cavity (11) and the collection container (22). The U-shaped pipe section includes a first longitudinal pipe (251) connected to the first cavity (11), a second longitudinal pipe (252) connected to the collection container (22), and a transverse pipe (253) connecting the first longitudinal pipe (251) and the second longitudinal pipe (252). The heat insulation component (26) includes a heating device (261) for heating the transverse pipe (253) arranged along the extension direction of the transverse pipe (253) and a heat insulation layer covering the first longitudinal pipe (251) and the second longitudinal pipe (252).

3. The apparatus for preparing tantalum powder for capacitors as described in claim 2, characterized in that, The connecting pipe (25) further includes a first on-off valve (256) disposed on the first longitudinal pipe (251) for controlling the opening and closing of the first longitudinal pipe (251) and a second on-off valve (257) disposed on the second longitudinal pipe (252) for controlling the opening and closing of the second longitudinal pipe (252).

4. The apparatus for preparing tantalum powder for capacitors as described in claim 3, characterized in that, The collecting component (2) also includes a pressure detection device (27) for detecting the pressure of the gas passing through the connecting pipe (25).

5. The apparatus for preparing tantalum powder for capacitors as described in claim 1, characterized in that, The main body (21) also includes a second cavity, in which the collection container (22) is detachably disposed.

6. The apparatus for preparing tantalum powder for capacitors as described in any one of claims 1 to 5, characterized in that, The second temperature control device (23) includes a water-cooled pipe and / or an external spray system disposed on the main body (21), wherein the water-cooled pipe is used to introduce cooling water and the external spray system is used to spray cooling water onto the main body (21).

7. The apparatus for preparing tantalum powder for capacitors as described in claim 1, characterized in that, The preparation component (1) also includes an insulated top cover (14) for sealing the first cavity (11), and the connecting pipe (25) extends into the top of the first cavity (11) after passing through the insulated top cover (14).

8. The apparatus for preparing tantalum powder for capacitors as described in claim 1, characterized in that, The preparation component (1) further includes a temperature measuring device (15), which is located on the top of the first cavity (11) and is configured to detect the temperature of the first cavity (11).

9. The apparatus for preparing tantalum powder for capacitors as described in claim 1, characterized in that, The collection container (22) is made of nickel-based alloy material.

10. A method for preparing tantalum powder for capacitors, characterized in that, Using the apparatus for preparing tantalum powder for capacitors as described in any one of claims 1 to 9, the method for preparing tantalum powder for capacitors includes: step a, placing the material for preparing tantalum powder in the reactor dish located in the first chamber (11), and using the first temperature control device (12) to heat the first chamber (11) to cause the material to undergo a reduction reaction to prepare tantalum powder; the material includes tantalum oxide and magnesium powder; step b, after the material reduction reaction is completed, using the second temperature control device (23) to maintain the temperature of the collection container (22) below the condensation temperature of magnesium vapor, and collecting the magnesium vapor in the first chamber (11) into the collection container (22) through the collection component (2).

11. The method for preparing tantalum powder according to claim 10, characterized in that, Step b further includes: after the material reduction reaction is completed, the temperature of the first chamber (11) is changed to 650℃~850℃, and then the magnesium vapor in the first chamber (11) is collected in the collection container (22).

12. The method for preparing tantalum powder according to claim 11, characterized in that, Step b further includes: using the suction component to generate negative pressure on the connecting port (24), and controlling the collection time of the collection component (2) for magnesium vapor to be 3h~20h.

13. The method for preparing tantalum powder according to claim 12, characterized in that, The suction component generates a negative pressure of -0.1MPa to -0.05MPa on the connecting port (24).

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