Rotary kiln for reducing tantalum and niobium oxides by using gaseous magnesium

Abstract

The utility model discloses a rotary kiln for reducing tantalum and niobium oxides by using gaseous magnesium, which belongs to the technical field of metal reduction and comprises a rotary kiln body and a gas inlet spray gun. The rotary kiln body comprises a feeding port, an air outlet, a discharging port and an air inlet. The gas inlet spray gun comprises a main flow channel used for circulating gaseous magnesium, at least one rotating node exists between the gas inlet spray gun and the gas inlet, the main flow channel is communicated with an inner cavity of the rotary kiln body through the gas inlet, and an annular jet flow nozzle is formed in the side wall of a cavity body of the main flow channel and used for forming annular gas jet flow on the periphery of the gaseous magnesium. And annular inert gas high-speed jet flow is jetted out through an annular jet flow nozzle arranged near the rotating node. The annular gas jet forms a layer of constraint at the periphery of the gaseous magnesium to prevent the gaseous magnesium from diffusing to the periphery, so that the gaseous magnesium is prevented from being in contact with the rotating node, the service life of the rotating node is effectively prolonged, and the maintenance cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of metal reduction, and specifically relates to a rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium. Background Art

[0002] As rare metals, tantalum and niobium are widely used in the electronics industry due to their unique chemical and physical properties, especially in the manufacture of high-performance capacitors. The basic working principle of tantalum capacitors is based on the anodic oxidation of tantalum. By generating a dense tantalum oxide film on the surface of tantalum powder. This film serves as the dielectric of the capacitor and has a high dielectric constant, enabling a large capacitance to be provided in a small volume. The working principle of niobium capacitors is similar to that of tantalum capacitors, and the niobium oxide film has slightly different dielectric properties but also shows excellent performance.

[0003] The production of tantalum and niobium powders requires highly controlled material purity, particle size distribution, and particle morphology to meet the requirements of high-performance capacitor manufacturing. Common production methods include vacuum carbon reduction method, hydrogen reduction method, and sodium reduction method. Among them, the metal powder produced by the vacuum carbon reduction method has a high impurity content and is severely contaminated by carbon; the hydrogen reduction method has certain safety risks during the process manufacturing and requires high production equipment; the sodium reduction method has a complex process and high cost, especially in dealing with by-products (such as sodium oxides) requires special processes.

[0004] Over the years, people have made many attempts to develop alternative methods for reducing tantalum and niobium oxides to the metallic state, including using metallic magnesium. The mixture is placed in a reaction vessel such as a rotary kiln, and the reaction vessel is placed in a vacuum or an inert atmosphere (such as argon) to prevent oxidation and impurity mixing. Gaseous magnesium reacts with tantalum oxide or niobium oxide to generate powdered metallic tantalum or niobium.

[0005] However, the production and transportation of gaseous metals such as magnesium to the reaction zone are extremely difficult. Gaseous magnesium may condense at any cold point in the transmission path to cause blockage, especially at the rotating node positions of the rotary kiln. Over time, the metal will erode components such as the container, seals, and bearings to reduce their integrity, resulting in serious maintenance problems. Summary of the Utility Model

[0006] The purpose of the utility model is to provide a rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium to solve the problems mentioned in the above existing technologies.

[0007] Provided is a rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium, comprising:

[0008] The rotary kiln body, which includes a feed inlet and an air outlet at the upstream end of the material, and a discharge outlet and an air inlet at the downstream end of the material;

[0009] An intake spray gun, the intake spray gun includes a main flow channel for gaseous magnesium to flow through. There is at least one rotation node between the intake spray gun and the intake port. The main flow channel is communicated with the inner cavity of the rotary kiln body through the intake port. An annular jet nozzle is arranged on the side wall of the cavity of the main flow channel, and the annular jet nozzle is used to form an annular gas jet around the gaseous magnesium.

[0010] Furthermore, the intake port is formed by a through hole opened on the end wall of the rotary kiln body, and the intake spray gun is rotationally connected to the through hole on the rotary kiln body through a rotation node. Since the output end of the intake spray gun is located inside the rotary kiln body, the annular gas jet formed by the annular jet nozzle can directly spray into the rotary kiln body after constraining the gaseous magnesium, which can shorten the conveying path of the gaseous magnesium.

[0011] Furthermore, the extension line of the gas jet direction of the intake spray gun forms an angle of α degrees with the rotation center axis of the rotary kiln body, and the α angle is 2° - 6°. The intake spray gun constrains the gaseous magnesium and sprays it at a certain angle relative to the rotary kiln body onto tantalum and niobium oxides, which can improve the contact effect between the gaseous magnesium and tantalum and niobium oxides, and thus improve the reaction rate of gaseous magnesium per unit volume.

[0012] Furthermore, the intake port is fixedly connected to the end wall of the rotary kiln body, the intake spray gun is rotationally connected to the intake port through a rotation node, and an energy dissipator is arranged in the intake port. The intake spray gun is communicated with the rotary kiln body through the intake port. The annular gas jet formed by the annular jet nozzle is dissipated in the intake port and then mixed with the gaseous magnesium and enters the rotary kiln body, which can reduce the flow rate of the gaseous magnesium, and thus increase the contact time between the gaseous magnesium and tantalum and niobium oxides.

[0013] Furthermore, annular jet nozzles arranged in a multi-layer stepped manner are arranged on the side wall of the cavity of the main flow channel. The multi-layer annular gas jets formed by the multi-layer annular jet nozzles can improve the constraint effect, maintain the stable state of the laminar flow, and delay the constraint path.

[0014] Furthermore, a booster pump is connected to the intake end of the annular jet nozzle. The booster pump can control the jet rate and intake amount of the annular gas jet to correspond to different usage situations of gaseous magnesium.

[0015] Furthermore, an air extraction pump is connected to the outlet, and the air extraction pump forms a negative pressure at the outlet end to enhance the directional flow ability of the gas and prevent some gas from flowing back to the rotation node.

[0016] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0017] Since the reaction process between gaseous magnesium and tantalum and niobium oxides needs to be carried out in an oxygen-free environment, it is a more preferred solution to introduce an inert gas into the rotary kiln body to form an inert atmosphere. In order to solve the problem that gaseous magnesium condenses at the rotating node position during the transportation process, causing corrosion of the seals and bearings at the rotating node, a ring-shaped inert gas high-speed jet is ejected through a ring-shaped jet nozzle arranged near the rotating node. The ring-shaped gas jet forms a layer of restraint around the gaseous magnesium to prevent the gaseous magnesium from diffusing around, avoiding the contact between the gaseous magnesium and the rotating node, effectively improving the service life at the rotating node and reducing the maintenance cost. Brief Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present drawings or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following-described drawings are only some embodiments of the present drawings. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0019] Figure 1 It is a schematic diagram A of the overall structure of a rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium;

[0020] Figure 2 It is Figure 1 an enlarged view of area A in

[0021] Figure 3 It is a schematic diagram B of the overall structure of a rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium;

[0022] Figure 4 It is Figure 3 an enlarged view of area B in

[0023] Figure 5 It is a schematic diagram of the structure of the intake spray gun in an embodiment of the present utility model.

[0024] In the figure: 1, rotary kiln body; 11, feed inlet; 12, air outlet; 13, discharge outlet; 14, intake port; 141, energy dissipator; 2, intake spray gun; 21, main flow channel; 22, ring-shaped jet nozzle; 3, rotating node. Detailed Embodiments

[0025] In order to make the purpose, technical solutions and advantages of the present application clearer, the following will describe and explain the present application in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Based on the embodiments provided by the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0026] Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. In addition, it can also be understood that although the efforts made in such a development process may be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacturing, or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be understood as the content disclosed in the present application being insufficient.

[0027] However, there will be cases where unnecessary details are omitted. For example, there are cases where the detailed description of well-known matters and the repeated description of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter recited in the claims.

[0028] Please refer to Figures 1-4 As shown, in an embodiment of the present utility model, a rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium includes a rotary kiln body 1 and an intake spray gun 2. The rotary kiln body 1 includes a feed inlet 11 and an air outlet 12 at the upstream end of the material, and a discharge outlet 13 and an air inlet 14 at the downstream end of the material. The intake spray gun 2 includes a main flow channel 21 for circulating gaseous magnesium. There is at least one rotation node 3 between the intake spray gun 2 and the air inlet 14. The main flow channel 21 is communicated with the inner cavity of the rotary kiln body 1 through the air inlet 14. A ring-shaped jet nozzle 22 is provided on the side wall of the cavity of the main flow channel 21. The ring-shaped jet nozzle 22 is used to form a ring-shaped gas jet around the gaseous magnesium.

[0029] Since the reaction between gaseous magnesium and tantalum and niobium oxides needs to be carried out in a closed environment to facilitate the formation of an inert atmosphere by inert gas in the rotary kiln body 1, the downstream end of the material of the rotary kiln body 1 is sealed by an end cover, and the material is discharged from the rotary side wall of the rotary kiln body 1. The intake spray gun 2 or the air inlet 14 is arranged at the end cover, and gaseous magnesium is conveyed into the inner cavity of the rotary kiln body 1 through the main flow channel 21. At the same time, an inert gas (such as argon) is ejected through the ring-shaped jet nozzle 22 to form a ring-shaped gas jet. The ring-shaped jet nozzle 22 is arranged near the upstream of the relative rotation node 3 in the intake spray gun 2. The ring-shaped gas jet surrounds the gaseous magnesium to form a layer of restraint to prevent the diffusion of gaseous magnesium, so as to protect the rotation node 3.

[0030] In one embodiment, please refer to Figure 1 and Figure 2As shown, the air inlet 14 is formed by a through hole opened in the end wall of the rotary kiln body 1. The air inlet spray gun 2 is rotatably connected to the through hole on the rotary kiln body 1 through a rotating node 3. The air inlet spray gun 2 can directly input gaseous magnesium and an annular inert gas jet into the inner cavity of the rotary kiln body 1. The gaseous magnesium is guided towards the upstream end of the material in the rotary kiln body 1, and the gaseous magnesium is isolated from the rotating node 3 at the end cover by the annular inert gas to play a protective role. In this solution, since the air inlet spray gun 2 can directly act on tantalum and niobium oxides, the flow path of the gaseous magnesium is shortened, and the influence of the gaseous magnesium on the cavity wall of the conveying pipeline is reduced.

[0031] The extension line of the gas injection direction of the air inlet spray gun 2 forms an angle of α degrees with the rotation center axis of the rotary kiln body 1, and the α angle is 2° - 6°. This setting makes the gas tend to flow directly towards the material direction, improving the contact rate between the gaseous magnesium and the material, and avoiding waste of travel caused by most of the gas not participating in the reaction. It should be noted here that the gas injection direction of the air inlet spray gun 2 is controlled by the output direction of the output port of the main flow channel 21. In order not to cause interference when the rotary kiln body 1 rotates, the central axis of the main body structure of the air inlet spray gun 2 coincides with the rotation center axis of the rotary kiln body 1, while there is an angle of α degrees between the output port of the main flow channel 21 of the air inlet spray gun 2 and the rotation center axis of the rotary kiln body 1.

[0032] In one embodiment, please refer to Figure 3 and Figure 4 As shown, the air inlet 14 is fixedly connected to the end wall of the rotary kiln body 1. The air inlet spray gun 2 is rotatably connected to the air inlet 14 through a rotating node 3. An energy dissipator 141 is arranged in the air inlet 14. The structure between the air inlet 14 and the end cover of the rotary kiln body 1 is airtight, and the air inlet 14 is driven to rotate synchronously when the rotary kiln body 1 rotates. The air inlet spray gun 2 is transitioned with the rotary kiln body 1 through the air inlet 14. Therefore, the rotating node 3 is located between the end wall of the air inlet 14 and the air inlet spray gun 2, and the annular gas jet output from the annular jet nozzle 22 is used to protect the rotating node 3 here. In this solution, after the high-speed gas enters the air inlet 14, it is dissipated under the action of the energy dissipator 141 in the air inlet 14 to reduce the flow rate of the air flow, so that the reaction time of the gaseous magnesium in the rotary kiln body 1 is increased.

[0033] Specifically, the energy dissipator 141 can be a baffle with through holes, which changes the laminar flow into turbulent flow by disturbing the flow mode of the air flow to achieve the purpose of energy dissipation. In addition, the specific structure of the energy dissipator 141 can be selected according to actual needs as long as the purpose of energy dissipation can be achieved.

[0034] Please refer to Figure 5As shown, annular jet nozzles 22 arranged in a multi-layer stepped manner are provided on the side wall of the cavity of the main runner 21. When the conveying pipelines of the respective annular jet nozzles 22 operate independently and are supplied with gas through separate pump systems, the annular gas jets output by the outer annular jet nozzles 22 can supplement the inner annular gas jets that are decaying, and the regulation of the inert gas delivery power is more flexible. When the respective annular jet nozzles 22 are supplied with gas by a single pump system, the annular gas jets are significantly stratified after being ejected through the multiple annular jet nozzles 22, and the laminar flow effect reduces the attenuation rate of the gas jets, which can improve the isolation effect of the gas jets.

[0035] The intake end of the annular jet nozzle 22 is connected to a booster pump, and the booster pump can control the injection rate and intake amount of the annular gas jet formed by the inert gas to correspond to different gaseous magnesium usage situations.

[0036] The air outlet 12 is connected to an air extraction pump, and the air extraction pump forms a negative pressure at the air outlet 12 end to enhance the directional flow ability of the gas and prevent some gas from flowing back to the rotation node 3.

[0037] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same composition and the same effect as the technical idea within the technical solution scope of this application are all included in the technical scope of this application. In addition, within the scope not departing from the gist of this application, various deformations that those skilled in the art can think of imposed on the embodiments, and other ways constructed by combining some constituent elements in the embodiments are also included in the scope of this application.

Claims

1. A rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium, characterized in that, Comprising: The rotary kiln body (1), which includes a feed inlet (11) and an air outlet (12) at the upstream end of the material, and a discharge outlet (13) and an air inlet (14) at the downstream end of the material; An air inlet spray gun (2), the air inlet spray gun (2) includes a main flow channel (21) for flowing gaseous magnesium, there is at least one rotation node (3) between the air inlet spray gun (2) and the air inlet (14), the main flow channel (21) is communicated with the inner cavity of the rotary kiln body (1) through the air inlet (14), and an annular jet nozzle (22) is arranged on the side wall of the cavity of the main flow channel (21), and the annular jet nozzle (22) is used to form an annular gas jet around the gaseous magnesium.

2. A rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium according to claim 1, characterized in that, The air inlet (14) is formed by a through hole opened on the end wall of the rotary kiln body (1), and the air inlet spray gun (2) is rotatably connected to the through hole on the rotary kiln body (1) through the rotation node (3).

3. A rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium according to claim 2, characterized in that, The extension line of the gas injection direction of the air inlet spray gun (2) forms an angle of α degrees with the rotation center axis of the rotary kiln body (1), and the α angle is 2° - 6°.

4. A rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium according to claim 1, characterized in that, The air inlet (14) is fixedly connected to the end wall of the rotary kiln body (1), the air inlet spray gun (2) is rotatably connected to the air inlet (14) through the rotation node (3), and an energy dissipator (141) is arranged in the air inlet (14).

5. A rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium according to any one of claims 1-4, characterized in that, The annular jet nozzles (22) arranged in a multi-layer stepped manner are provided on the side wall of the cavity of the main flow channel (21).

6. A rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium according to any one of claims 1-4, characterized in that, A booster pump is communicated with the air inlet end of the annular jet nozzle (22).

7. A rotary kiln for reducing tantalum and niobium oxides with gaseous magnesium according to any one of claims 1-4, characterized in that, The air outlet (12) is communicated with an air extraction pump.

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