An extraction column device dedicated to continuous production of high-purity tantalum oxide

Abstract

The one or more embodiments of the specification provide an extraction column device special for continuously producing high-purity tantalum oxide; comprising a first extraction column, a second extraction column and a third extraction column connected in sequence. The first extraction column is used for extracting and washing a tantalum and niobium-containing liquid and discharging residual liquid, the bottom of the first extraction column is provided with a first heavy liquid outlet, the side wall of the first extraction column is provided with a first side wall feed inlet, and the first extraction column is provided with a partition plate and a liquid suction pipe; the second extraction column is used for stripping niobium from the organic phase from the first extraction column, the bottom of the second extraction column is provided with a bottom pipe, and the top of the second extraction column is provided with a top pipe; the third extraction column is used for stripping tantalum from the organic phase from the second extraction column, and the bottom of the third extraction column is provided with a second heavy liquid outlet; the columns are communicated through connecting pipes; and the extraction efficiency is significantly improved. The application replaces the mixed clarifier with the packed extraction column, upgrades the step-by-step contact mass transfer to continuous countercurrent contact mass transfer, and eliminates the clarification waiting time between stages.

Description

Technical Field

[0001] This invention relates to the field of extraction technology for high-purity tantalum oxide, and more particularly to an extraction tower device specifically designed for the continuous production of high-purity tantalum oxide. Background Technology

[0002] Tantalum (Ta) and niobium (Nb) are rare high-melting-point metals. Their compounds, high-purity tantalum oxide and high-purity niobium oxide, are widely used in high-tech fields such as electronics, aerospace, high-temperature alloys, optical glass, and medical devices.

[0003] Currently, the mainstream method for producing high-purity tantalum oxide in industry is solvent extraction, which involves using hydrofluoric acid-sulfuric acid to decompose tantalum and niobium mineral raw materials to obtain an acid leaching solution containing tantalum, niobium and impurities. Then, by utilizing the difference in the partition coefficients of tantalum and niobium in a specific extraction system, tantalum and niobium are separated through multi-stage extraction.

[0004] In existing hydrometallurgical processes for tantalum and niobium, the extraction and separation section typically uses a mixed clarification tank as the core extraction equipment. A typical process flow is as follows: after acid leaching, the active components (tantalum, niobium, and some impurities) are dissolved in an aqueous solution and sent to the mixed clarification tank for extraction. An extractant is used to extract both tantalum and niobium from the aqueous solution. Then, dilute sulfuric acid is used to wash away some of the impurities. The extraction solution containing tantalum and niobium is then back-extracted using a niobium-removing agent, allowing niobium to enter the aqueous phase for the production of high-purity niobium oxide. The remaining extractant contains only tantalum, which is then back-extracted using a tantalum-removing agent to obtain tantalum solution for the production of high-purity tantalum oxide. In existing technologies, niobium-removing agent washing typically requires 20 stages, and tantalum-removing agent extraction requires 10 stages.

[0005] However, the existing process using a mixing clarifier has the following prominent technical problems: First, the long material residence time leads to delayed product quality control. Due to the long extraction route and the need for numerous extraction stages, the residence time of materials from entering the system to producing qualified products exceeds two days. If fluctuations in individual process parameters cause product quality defects, by the time this is discovered, two days' worth of defective products have already accumulated in the system, making them impossible to process and resulting in significant economic losses for the company.

[0006] Secondly, the large amount of raw materials tied up in inventory results in significant capital expenditure. The mixing and clarification tanks have a large volume and contain a huge amount of raw materials. For example, in a factory with an annual output of 1,500 tons of oxides, the extraction tanks typically tie up more than 30 million yuan in capital annually.

[0007] Third, they require a large footprint. The mixing and clarification tank is a horizontal rectangular structure, and with multiple stages connected in series, it occupies a vast area. For example, in a plant producing 1500 tons of oxides annually, the extraction tank occupies over 1000 square meters. 2 .

[0008] Fourth, cleaning is difficult. Solid impurities are generated during the tantalum-niobium extraction process, causing equipment blockage. The mixing and clarification tank needs to be cleaned 2-4 times a year, each time requiring 6 workers to work continuously for about 7 days, which is labor-intensive and results in long downtime.

[0009] Fifth, extraction efficiency is limited. The mixing and clarification tank is a staged contact extraction method, and each stage requires a mixing chamber and a clarification chamber. The efficiency between stages is limited by the clarification rate. Increasing the number of extraction stages means that the equipment size and footprint will increase exponentially, which limits further improvement in product purity.

[0010] Existing technologies include continuous extraction towers with detachable structures, which facilitate disassembly and cleaning through modular tower structures. There are also reports of packed extraction towers being used in liquid-liquid extraction. However, none of the above technologies offer a systematic solution to the specific problem of solid impurity blockage during tantalum-niobium extraction, nor do they involve complete sets of equipment with multiple towers connected in series for the entire tantalum-niobium extraction process. Summary of the Invention

[0011] In view of this, the purpose of one or more embodiments of this specification is to provide an extraction tower device specifically for the continuous production of high-purity tantalum oxide, which addresses the problems of long material residence time, large material volume, large footprint, difficult cleaning, and limited extraction efficiency in existing mixed clarification tank extraction processes.

[0012] For the purposes described above, one or more embodiments of this specification provide an extraction tower device specifically for producing high-purity tantalum oxide, comprising a first extraction tower, a second extraction tower, and a third extraction tower connected in series.

[0013] The first extraction tower is used to extract and wash the feed liquid containing tantalum and niobium and discharge the residual liquid. The bottom of the tower is provided with a first heavy liquid outlet, the side wall of the tower body is provided with a first side wall feed inlet, and the tower is provided with a dividing plate and a liquid extraction pipe. The second extraction tower is used to back-extract niobium from the organic phase from the first extraction tower. It has a bottom port at the bottom and a top pipe at the top. The third extraction tower is used to back-extract tantalum from the organic phase from the second extraction tower, and a second heavy liquid outlet is provided at the bottom of the tower; the towers are connected by connecting pipes.

[0014] Furthermore, the dividing plate is provided with filter through holes, and the pipe wall or opening of the liquid extraction tube is provided with filter holes, thus the dividing plate and the liquid extraction tube constitute a two-stage filtration structure.

[0015] Furthermore, each extraction tower is provided with a top cover, on which a first threaded hole and a second threaded hole are provided, a groove is provided on the top cover, a sealing ring is provided in the groove, and an inner hole is provided in the center of the top cover.

[0016] Furthermore, the second threaded hole has a dual-mode working state; In the first working state, screw in the fastening bolts to engage with the first threaded hole to fix the top cover onto the tower flange; In the second working state, the hollow connector is screwed in as an auxiliary feeding channel independent of the inner hole.

[0017] Each extraction tower is equipped with a flange located below the light liquid inlet and above the heavy liquid inlet.

[0018] It also includes a washing mechanism, which is provided with a first drain outlet, a second drain outlet, a side pipe and an inlet pipe.

[0019] As another technical solution, a continuous extraction process using the above-mentioned extraction tower equipment is provided, characterized by the following steps: introducing a feed liquid containing tantalum and niobium and an extractant into a first extraction tower, and performing countercurrent extraction and washing with the heavy liquid as the continuous phase and the light phase as the dispersed phase to obtain a loaded organic phase; The supported organic phase is introduced into the second extraction tower and contacted countercurrently with the anti-niobium agent to obtain an organic phase containing only tantalum; An organic phase containing only tantalum is introduced into the third extraction tower and contacted countercurrently with an anti-tantalum agent to obtain a high-purity tantalum solution.

[0020] Furthermore, in the first extraction tower, the low-concentration primary wash water, after contacting the organic phase through at least one packing layer, is mixed with the acid-adjusting solution and continues to contact the organic phase.

[0021] Furthermore, if the flow rate of a certain phase in any tower is insufficient, nitrogen is introduced to promote the upward movement of the organic phase. The nitrogen is then discharged after recovering the entrained organic phase in the recovery tank.

[0022] Furthermore, the extractant is a 2-octanol system, with a 2-octanol volume fraction of 85%~100%; The anti-niobium agent is 3~3.5 mol / L pure water; the anti-tantalum agent is 2.5~3.5 mol / L dilute sulfuric acid.

[0023] The present invention has the following advantages over the prior art: First, the extraction efficiency is significantly improved. This invention uses a packed extraction tower instead of a mixing and clarification tank, upgrading the stepwise contact mass transfer to a continuous countercurrent contact mass transfer, eliminating the inter-stage clarification waiting time; by selecting the heavy liquid as the continuous phase and the light phase as the dispersed phase and precisely controlling the droplet size and feed rate, a larger phase contact area and a higher mass transfer coefficient are obtained.

[0024] Second, product quality is controllable in real time. The residence time of materials from entering the system to producing qualified products is reduced from more than 2 days in the past to 50-65 minutes, a reduction of about 98%. When process parameters fluctuate, the amount of defective products generated is reduced by 98%, greatly reducing production risks.

[0025] Third, inventory and floor space have been significantly reduced. For example, a factory producing 1500 tons of oxides annually saw its inventory costs decrease from over 30 million to approximately 600,000, and its floor space from 1000 square meters... 2 The above drops to approximately 100m 2 .

[0026] Fourth, cleaning and maintenance are extremely convenient. The two-stage filtration system formed by the liquid extraction pipe 14 and the dividing plate 13 intercepts solid impurities at the source, preventing the packing layer from clogging; combined with the detachable flange slag discharge structure, it forms a complete anti-clogging solution of "source interception + end discharge". Cleaning time is reduced from 6 people × 7 days / time to 1 person × 1 day / time.

[0027] Fifth, it has strong fine-tuning capabilities. The second threaded hole 44 of the top cover 4 has a dual-mode working state, which can be used as a fastener or as an independent auxiliary feeding fine-tuning channel, realizing fine-tuning without stopping the machine or depressurizing. When combined with the nitrogen-assisted system, it forms a pressure closed loop, which significantly improves the system's operational stability.

[0028] Sixth, the product purity is higher. Due to the four-tower series segmented operation, the process conditions of each segment can be optimized independently, and solid impurities are effectively intercepted, the purity of tantalum oxide products can reach over 99.95%, and the tantalum recovery rate can reach over 98.5%. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in one or more embodiments of this specification or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one or more embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the overall structure of the extraction tower equipment of the present invention; Figure 2 This is a schematic diagram of the structure of the first extraction tower of the present invention; Figure 3 This is a schematic diagram of the structure of the third extraction tower of the present invention; Figure 4 This is a schematic diagram of the washing mechanism of the present invention; Figure 5 This is a structural schematic diagram of the invention from another perspective; Figure 6 For the present invention Figure 2 A magnified structural diagram of region A in the middle.

[0031] In the diagram: 1. First extraction tower; 11. First heavy liquid outlet; 12. First side wall feed inlet; 13. Dividing plate; 14. Liquid extraction pipe; 15. Connecting pipe; 2. Second extraction tower; 21. Feed pipe; 22. Side wall port; 23. Bottom port; 24. Top pipe; 3. Third extraction tower; 31. Second heavy liquid outlet; 32. Second side wall feed inlet; 33. Base frame; 34. Through hole; 4. Top cover; 41. Threaded hole; 42. Groove; 43. Sealing ring; 44. Threaded hole; 45. Inner hole; 5. Washing mechanism; 51. First drain outlet; 52. Second drain outlet; 53. Side pipe; 54. Liquid inlet pipe. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments.

[0033] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of this specification should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar words used in one or more embodiments of this specification do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] I. Overall Connection and Positional Relationships of the Equipment (I) Overall Layout This extraction tower equipment includes a first extraction tower 1, a second extraction tower 2, a third extraction tower 3, and a fourth extraction tower (standby tower) connected in series. Each tower is a vertical cylindrical packed extraction tower, which is arranged and installed on the equipment foundation in a horizontal direction.

[0035] The positional relationship between the towers is as follows: the first extraction tower 1 is located at the foremost (upstream), the second extraction tower 2 is located after the first extraction tower 1, the third extraction tower 3 is located after the second extraction tower 2, and the fourth extraction tower is located after the third extraction tower 3 as a backup. The central axes of the towers are parallel to each other, and the bottoms of the towers are located on the same horizontal plane.

[0036] (ii) Inter-tower connection relationship The top outlet of the first extraction tower (1) is connected to the bottom inlet (i.e., bottom port 23) of the second extraction tower 2 through a connecting pipe 15. One end of the connecting pipe 15 is welded or flanged to the side wall outlet of the top of the first extraction tower 1, and the other end is welded or flanged to the inlet of the bottom side wall of the second extraction tower 2. A control valve and a flow meter are installed on the connecting pipe 15 to regulate the flow rate of the organic phase entering the second extraction tower 2.

[0037] The top outlet (top pipe 24) of the second extraction tower 2 is connected to the bottom inlet of the third extraction tower 3 through the connecting pipe 15. One end of the top pipe 24 is welded or flanged to the central inner hole 45 of the top cover 4 of the second extraction tower 2, and the other end extends laterally along the top of the tower and then bends downward, connecting to the bottom inlet of the third extraction tower 3 through the connecting pipe 15.

[0038] The top outlet of the third extraction tower 3 is connected to the circulating organic phase inlet of the first extraction tower 1 through a connecting pipe 15, so as to realize the recycling of the blank organic phase.

[0039] The fourth extraction tower serves as a backup tower. Its inlet and outlet are connected to the connecting pipe 15 via bypass pipes. A switching valve is installed on the bypass pipe, which can be switched to be put into use when any extraction tower needs to be shut down for maintenance.

[0040] II. Specific structure, connection relationship and positional relationship of the first extraction tower 1 (a) Tower body The first extraction tower 1 is a vertical cylindrical steel structure tower body with its axis set in the vertical direction. The tower body is made of carbon steel lined with corrosion-resistant materials (such as polytetrafluoroethylene or glass enamel) to withstand the strong corrosion of the hydrofluoric acid-sulfuric acid system. The tower body is divided into the top section, the packing section and the bottom section from top to bottom.

[0041] The tower body has an upper flange at the top and a lower flange at the bottom. The upper flange is used to connect the top cover 4, and the lower flange is used to seal the bottom of the tower or connect the bottom pipes.

[0042] (ii) First heavy liquid outlet 11 Positional relationship: The first heavy liquid outlet 11 is located at the lowest point of the bottom of the first extraction tower 1, at the center of the bottom of the tower body or at the lowest point of the bottom side wall, to ensure that the heavy liquid (aqueous phase) in the tower can be completely discharged by gravity.

[0043] Connection: The first heavy liquid outlet 11 is a pipe joint structure, with one end welded to the opening at the bottom end cap of the tower body, and the other end connected to the external residual liquid discharge pipeline via a flange connection. A control valve is installed on this pipe joint to regulate the discharge flow rate of the residual liquid.

[0044] Function: The heavy liquid (aqueous phase, i.e. raffinate / residual liquid) as the continuous phase flows from top to bottom in the column and is discharged from the system through the first heavy liquid outlet 11.

[0045] (iii) First side wall feed inlet 12 Positional relationship: The first side wall feed inlet 12 is located in the lower middle part of the side wall of the first extraction tower 1, specifically below the packing section of the tower body. This position ensures that the introduced liquid and extractant can enter the tower below the packing section and flow upward or downward after mixing with the existing liquid phase in the tower.

[0046] Connection relationship: The first side wall feed port 12 is a pipe joint structure. Its root is welded to the opening on the side wall of the tower body. One end of the pipe joint extends into the tower body, and the other end is connected to the external feed pipe through a flange connection. The feed pipe is equipped with a feed pump, flow meter and control valve for precise control of feed flow.

[0047] Function: Used to introduce the acid leaching solution and / or extractant of the raw material to be extracted into the tower.

[0048] (iv) Divider 13 Positional relationship: The dividing plate 13 is horizontally set inside the first extraction tower 1, located in the middle of the packing section of the tower body, dividing the internal space of the tower body into an upper packing area and a lower packing area. The outer diameter of the dividing plate 13 is adapted to the inner diameter of the tower body, and a sealing structure (such as a sealing ring or welded seal) is provided between its edge and the inner wall of the tower body to prevent the liquid phase from short-circuiting along the tower wall without passing through the through holes on the dividing plate.

[0049] Connection relationship: The dividing plate 13 is fixedly connected to the inner wall of the tower body by a support member. The support member consists of multiple support blocks or support rings spaced apart along the circumference of the inner wall of the tower body. One end of the support block is welded to the inner wall of the tower body, and the other end supports the edge of the dividing plate 13. The dividing plate 13 and the support member are fixed by bolt connection or slot connection, which is convenient for disassembly and cleaning.

[0050] Structural details: The dividing plate 13 is a circular plate with multiple leakage holes and filter holes. The leakage holes have a diameter of 5-15 mm and are distributed in the central and outer areas of the plate, allowing the liquid phase to flow downwards through the dividing plate. The filter holes have a diameter of 0.5-3 mm and are distributed in the outer area of ​​the plate, trapping solid impurities as the liquid phase passes through. The total area of ​​the filter holes accounts for 10%-30% of the total area of ​​the dividing plate to ensure both filtration function and to avoid excessively increasing the resistance to liquid phase flow.

[0051] Function: ① Divide the internal space of the tower into different functional areas, so that low-concentration wash water and acid conditioning solution can enter in stages and come into contact with the organic phase in different areas; ② The filter holes on it trap residual fine solid impurities as the liquid phase passes through, completing the second stage of filtration; ③ Ensure smooth flow of liquid phase through leakage through-holes to maintain normal hydrodynamic state inside the tower.

[0052] (v) Liquid extraction tube 14 Positional relationship: The liquid extraction pipe 14 is installed inside the first extraction tower 1. It is arranged in a vertical or inclined direction. The lower end (liquid inlet) of the liquid extraction pipe 14 is located at a specific liquid level in the tower (such as above or below the dividing plate 13, the liquid extraction position is determined according to the process requirements). The upper end (liquid outlet) of the liquid extraction pipe 14 extends out of the tower through the side wall or top cover 4 of the tower body.

[0053] Connection relationship: The upper end of the liquid extraction pipe 14 is connected to the external piping system of the tower body through a flange connection or welding. A sealing sleeve is provided at the position where the liquid extraction pipe 14 passes through the side wall of the tower body. The sealing sleeve is welded to the opening of the side wall of the tower body. The liquid extraction pipe 14 passes through the sealing sleeve and achieves dynamic or static sealing through sealing packing or sealing ring. The liquid extraction pipe 14 is fixedly connected to the inner wall of the tower body through pipe clamps or brackets to prevent it from shaking under liquid impact.

[0054] Structural details: The wall or inlet of the liquid extraction tube 14 is provided with filter holes. Specifically, multiple filter holes with a diameter of 1~5mm are opened on the wall of the liquid inlet end of the liquid extraction tube 14, distributed in the circumferential and axial directions of the tube wall. Alternatively, a filter screen is provided at the liquid inlet of the liquid extraction tube 14, with a mesh size of 1~5mm. The filter screen is fixed to the liquid inlet end of the liquid extraction tube 14 by threaded connection or snap-fit ​​connection. The filter holes or filter screen intercept large solid particles when the liquid phase is extracted, completing the first stage of solid-liquid separation. The diameter of the filter holes or filter screen is larger than the diameter of the filter through holes on the dividing plate 13 (0.5~3mm), forming a graded relationship of "large holes in front (liquid extraction tube), small holes in back (dividing plate)" to achieve graded interception.

[0055] Function: ① To extract the liquid phase from a specific location within the tower and guide it to a designated area or the next process; ② The first-stage solid-liquid separation is completed simultaneously with the suction of liquid phase through the filtration structure of its pipe wall or pipe opening, intercepting large solid particles and preventing them from entering subsequent pipelines and equipment; ③ In conjunction with the filter holes of the dividing plate 13, a two-stage filtration system of "large particle interception + fine impurity retention" is formed.

[0056] III. Specific structure, connection relationship and positional relationship of the second extraction tower 2 (a) Tower body The second extraction tower 2 is a vertical cylindrical steel structure tower body with its axis set vertically. The tower body material is the same as that of the first extraction tower 1. The tower body is divided into a top section, a packing section, and a bottom section from top to bottom. The top of the tower body is equipped with an upper flange for connecting the top cover 4, and the bottom is equipped with a lower flange for sealing the bottom of the tower.

[0057] (ii) Feed pipe 21 Positional relationship: The feed pipe 21 is located at the top of the second extraction tower 2, specifically in the center or side wall of the top cover 4, and is used to introduce an organic phase containing tantalum and niobium (from the top of the first extraction tower) into the tower.

[0058] Connection relationship: The feed pipe 21 is fixed to the inner hole 45 or the dedicated feed port on the top cover 4 by means of flange connection. Its lower end extends into the interior of the tower body and is connected to a liquid distributor. The upper end of the feed pipe 21 is connected to the connecting pipe 15 from the top of the first extraction tower 1 by means of flange connection.

[0059] Function: To introduce the supported organic phase from the first extraction tower 1 into the second extraction tower 2.

[0060] (iii) Side wall pipe opening 22 Positional relationship: The side wall port 22 is located in the upper middle part of the side wall of the second extraction tower 2, above the packing section.

[0061] Connection relationship: The side wall pipe port 22 is a pipe joint structure. Its root is welded to the opening on the side wall of the tower body. One end extends into the tower body and is connected to a liquid distributor. The other end is connected to the external anti-niobium agent supply pipeline through a flange connection. The anti-niobium agent supply pipeline is equipped with a delivery pump, flow meter and control valve.

[0062] Function: Serves as the inlet for the anti-niobium agent, introducing the anti-niobium agent (pure water or dilute sulfuric acid solution) into the tower.

[0063] (iv) Bottom pipe opening 23 Positional relationship: The bottom port 23 is located at the lowest point of the bottom of the second extraction tower 2, at the center of the bottom end cap or the lowest side wall of the tower body.

[0064] Connection relationship: The bottom pipe port 23 is a pipe joint structure. One end is welded to the opening of the bottom end cap of the tower body, and the other end is connected to the external niobium liquid discharge pipe through a flange connection. A control valve is installed on the discharge pipe.

[0065] Function: The high-purity niobium solution obtained from back-extraction is discharged from the bottom of the tower and sent to the subsequent process for producing high-purity niobium oxide.

[0066] (v) Top pipe 24 Positional relationship: The top pipe 24 is located at the top of the second extraction tower 2, and its lower end is connected to the central inner hole 45 of the top cover 4 or a dedicated outlet.

[0067] Connection relationship: The top pipe 24 is fixed to the top cover 4 by a flange connection. Its lower end is connected to the inside of the tower body, and its upper end extends horizontally along the top of the tower and then bends downward. It is connected to the connecting pipe 15 by a flange connection. The other end of the connecting pipe 15 is connected to the bottom feed port of the third extraction tower 3.

[0068] Function: The organic phase containing only tantalum after niobium back-extraction is discharged from the top of the column and sent to the third extraction column 3.

[0069] IV. Specific structure, connection relationship and positional relationship of the third extraction tower 3 (a) Tower body The third extraction tower 3 is a vertical cylindrical steel structure tower body with its axis set in the vertical direction. The tower body material is the same as that of the first extraction tower 1. The top of the tower body is equipped with an upper flange for connecting the top cover 4, and the bottom is equipped with a lower flange for sealing the bottom of the tower.

[0070] (ii) Second heavy liquid outlet 31 Positional relationship: The second heavy liquid outlet 31 is located at the lowest point of the bottom of the third extraction tower 3, at the center of the bottom head of the tower body or at the lowest side wall.

[0071] Connection: The second heavy liquid outlet 31 is a pipe joint structure, with one end welded to the opening at the bottom end cap of the tower body, and the other end connected to the external tantalum liquid discharge pipeline via a flange connection. A control valve is installed on the discharge pipeline.

[0072] Function: The high-purity tantalum solution obtained from back-extraction is discharged from the bottom of the tower and sent to the subsequent process for producing high-purity tantalum oxide.

[0073] (iii) Second side wall feed inlet 32 Positional relationship: The second side wall inlet 32 ​​is located in the upper middle part of the side wall of the third extraction tower 3, above the packing section.

[0074] Connection: The feed inlet 32 ​​on the second side wall is a pipe joint structure, with its root welded to the opening on the side wall of the tower. One end extends into the tower body and is connected to a liquid distributor, while the other end is connected to the external anti-tantalum agent supply pipeline via a flange connection. The anti-tantalum agent supply pipeline is equipped with a delivery pump, a flow meter, and control valves.

[0075] Function: Used to introduce anti-tantalum agent (dilute sulfuric acid solution) into the tower.

[0076] (iv) Base frame 33 Positional relationship: The base frame 33 is set at the bottom of the third extraction tower 3, below the lower flange of the tower body.

[0077] Connection relationship: The upper end of the base frame 33 is fixed to the lower flange or support skirt at the bottom of the tower body by bolts or welding, and the lower end of the base frame 33 is fixed to the equipment foundation by anchor bolts. The base frame 33 is a steel frame structure, which is composed of multiple columns and beams welded or bolted together.

[0078] Function: To support the third extraction tower 3, fix the tower body to the equipment foundation, and bear the gravity load of the tower body and the materials inside.

[0079] (v) Through hole 34 Positional relationship: Through hole 34 is set on the side wall of the third extraction tower 3, at an appropriate height position of the tower body (such as the middle or bottom of the packing section).

[0080] Connection relationship: Through hole 34 is a through hole opened on the side wall of the tower body. A pipe joint is welded on the outside of it. The pipe joint is connected to the external pipeline or instrument through a flange connection. When the through hole 34 is not in use, it is closed by a blind flange or a plug.

[0081] Function: Used to connect pipelines (such as sampling pipelines, venting pipelines) or install instruments (such as thermometers, pressure gauges, level gauges) to facilitate monitoring and control of the operating status inside the tower.

[0082] V. Specific structure, connection relationship and positional relationship of top cover 4 (a) Overall top cover Each extraction tower (first extraction tower 1, second extraction tower 2, third extraction tower 3 and fourth extraction tower) is provided with a top cover 4. The top cover 4 is a circular cover plate structure and is set at the upper flange of the tower body. The outer diameter of the top cover 4 is consistent with the outer diameter of the upper flange of the tower body. The inner surface (lower surface) of the top cover (4) is set opposite to the sealing surface of the upper flange of the tower body.

[0083] (ii) First threaded hole 41 Positional relationship: The first threaded hole 41 is opened in the edge area of ​​the top cover 4 and is evenly distributed along the circumference of the top cover 4. The position of the first threaded hole 41 corresponds one-to-one with the position of the bolt hole on the flange of the tower body.

[0084] Connection relationship: The first threaded hole 41 is a threaded through hole that passes through the upper and lower surfaces of the top cover 4. After the bolt passes through the first threaded hole 41 and the bolt hole of the flange on the tower body, the top cover (4) is fixedly connected to the flange on the tower body with the nut. The preload of the bolt is transmitted to the sealing ring 43 through the top cover 4, so that the sealing ring 43 is compressed and fills the groove 42, thereby achieving the sealing of the top of the tower.

[0085] Function: As the main fastening hole, the top cover 4 is fixed to the upper flange of the tower body by bolts, and provides basic pre-tightening force to compress the sealing ring 43 to ensure the sealing of the tower top.

[0086] (iii) Groove 42 and sealing ring 43 Positional relationship: The groove 42 is formed on the lower surface (inner surface) of the top cover 4. It is an annular groove, and its shape is adapted to the sealing surface of the flange on the tower body. The groove 42 is located inside the first threaded hole 41, that is, the diameter of the groove 42 is smaller than the diameter of the circumference of the first threaded hole 41. The sealing ring 43 is set inside the groove 42.

[0087] Connection relationship: The sealing ring 43 is embedded in the groove 42, and the cross-sectional shape of the sealing ring 43 is adapted to the cross-sectional shape of the groove 42 (such as the circular cross-section of the O-ring is adapted to the semi-circular cross-section of the groove). The sealing ring 43 is made of corrosion-resistant elastic material (such as fluororubber, polytetrafluoroethylene coated rubber, etc.). When the top cover 4 is fastened to the upper flange of the tower body through the bolt in the first threaded hole 41, the sealing ring 43 is compressed between the top cover 4 and the upper flange of the tower body. Its elastic deformation fills the tiny gap between the lower surface of the top cover 4 and the sealing surface of the upper flange of the tower body, thus achieving a seal.

[0088] Function: The groove 42 is used to accommodate and position the sealing ring 43, preventing the sealing ring 43 from shifting during compression; the sealing ring 43 undergoes elastic deformation under the action of bolt preload, filling the gap between the top cover and the tower flange, achieving a seal at the top of the tower, and preventing leakage of liquid and gas inside the tower.

[0089] (iv) Second threaded hole 44 Positional relationship: The second threaded hole 44 is opened in the area between the edge and the center of the top cover 4, located inside the circumference of the first threaded hole 41 and outside the inner hole 45. The number of second threaded holes 44 is 8 to 18, which are distributed at intervals along the circumference of the top cover 4. The position of the second threaded hole 44 does not interfere with the functional areas of the first threaded hole 41, the groove 42 and the inner hole 45.

[0090] Connection relationships: The second threaded hole 44 is a threaded through hole that penetrates the upper and lower surfaces of the top cover 4, and it has two working states: First working state (as fastening hole): The fastening bolt is screwed into the second threaded hole 44. The bolt passes through the second threaded hole 44 and presses against the upper surface of the top cover 4. In this state, the second threaded hole 44 and the first threaded hole 41 work together to provide additional preload force, pressing the top cover 4 against the sealing ring 43 and fixing it to the flange on the tower body.

[0091] Second working state (as an auxiliary feeding channel): A hollow connector (such as a pipe connector with external threads) is screwed into the second threaded hole 44. The lower end of the hollow connector extends into the second threaded hole 44 and enters the tower body. The upper end of the hollow connector is connected to an external regulator supply source or online detection instrument through a pipe. In this state, the second threaded hole 44 serves as an auxiliary feeding fine-tuning channel or detection channel independent of the inner hole 45.

[0092] Function: ① In the first working state, it serves as an auxiliary fastening hole to enhance the connection strength between the top cover 4 and the tower flange; ② In the second working state, it serves as an independent auxiliary feed fine-tuning channel, used to selectively introduce trace amounts of regulators (such as surfactants, pH regulators, etc.) into the tower or insert online detection probes (such as pH electrodes, temperature probes, etc.) to achieve fine control without stopping the machine or depressurizing. ③ Since the top cover 4 is provided with basic preload by the main bolt in the first threaded hole 41, the switching of the working state of the second threaded hole 44 does not affect the overall compression ratio of the sealing ring 43, thus ensuring the reliability of the seal.

[0093] (v) Inner hole 45 Positional relationship: The inner hole 45 is located in the center of the top cover 4, that is, the central axis of the inner hole 45 coincides with the central axis of the tower body.

[0094] Connection: The inner hole 45 is a circular through hole that penetrates the upper and lower surfaces of the top cover 4. Its inner diameter is adapted to the outer diameter of the pipe. The pipe extends into the tower body through the inner hole 45. A sealing structure (such as a sealing packing gland or mechanical seal) is provided between the pipe and the inner hole 45. The pipe is fixed to the top cover 4 by flange connection or welding.

[0095] Function: As an outlet pipe or passageway for the light phase (organic phase) or internal pipeline, in the first extraction tower 1, the inner hole 45 is used to pass through the output pipe of the loaded organic phase; in the second extraction tower 2, the inner hole 45 is used to pass through the output pipe containing only tantalum organic phase (i.e., top pipe 24); in the third extraction tower 3, the inner hole 45 is used to pass through the output pipe of the blank organic phase.

[0096] The specific structure, connection relationship and positional relationship of the washing mechanism 5 (a) Overall washing facility The washing mechanism 5 is installed in the washing section of the first extraction tower 1, located in the washing area outside the tower body or on the side wall of the tower body, and is used to wash the organic phase during the extraction process to remove impurities.

[0097] (ii) First drain port 51 and second drain port 52 Positional relationship: The first drain port 51 and the second drain port 52 are respectively located at different heights on the side wall of the housing of the washing mechanism 5. The first drain port 51 is located in the upper middle part of the washing mechanism 5 and is used to discharge the waste liquid generated in the first stage of the washing process. The second drain port 52 is located at the bottom or lower middle part of the washing mechanism 5 and is used to discharge the waste liquid generated in the second stage of the washing process.

[0098] Connection relationship: Both the first drain port 51 and the second drain port 52 are pipe joint structures. One end of the pipe joint is welded or threaded to the opening on the side wall of the washing mechanism 5, and the other end is connected to the external waste liquid collection pipe through a flange connection. A control valve is installed on the drain pipe.

[0099] Function: To separately discharge waste liquid generated in different washing stages, achieving graded discharge and treatment of washing waste liquid.

[0100] (III) Side tube 53 Positional relationship: The side tube 53 is set on the side wall of the shell of the washing mechanism 5, with one end connected to the washing mechanism 5 and the other end connected to the side wall of the first extraction tower 1.

[0101] Connection relationship: The two ends of the side pipe 53 are fixed to the shell of the washing mechanism 5 and the tower body of the first extraction tower 1 by flange connection or welding respectively. The side pipe 53 connects the internal space of the washing mechanism 5 with the internal space of the tower body of the first extraction tower 1. The side pipe 53 is equipped with a control valve to control the flow of washing liquid or material.

[0102] Function: Connects the washing mechanism 5 to the first extraction tower 1 for introducing washing liquid or discharging waste liquid.

[0103] (iv) Liquid inlet pipe 54 Positional relationship: The liquid inlet pipe 54 is located on the top of the housing or the upper part of the side wall of the washing mechanism 5, at the highest position of the washing mechanism 5.

[0104] Connection relationship: The liquid inlet pipe 54 is a pipe joint structure. One end is welded or threaded to the opening of the housing of the washing mechanism 5, and the other end is connected to the external fresh washing liquid supply pipeline through a flange connection. The washing liquid supply pipeline is equipped with a delivery pump, a flow meter and a control valve.

[0105] Function: To supply fresh detergent to the washing unit 5, ensuring that the detergent is sufficient.

[0106] Connection and positional relationships of the nitrogen-assisted system This equipment is also equipped with a nitrogen-assisted delivery system, which is used to promote the upward movement of the organic phase when the flow rate of a certain phase in any extraction tower is insufficient.

[0107] Each extraction tower (first extraction tower 1, second extraction tower 2, and third extraction tower 3) has a nitrogen inlet pipe on the bottom side wall. One end of the nitrogen inlet pipe is welded to the opening at the bottom of the tower side wall, and the other end is connected to an external nitrogen source through a pipe. The nitrogen inlet pipe is equipped with a pressure reducing valve, a flow meter, and a control valve to regulate the nitrogen pressure and flow rate entering the tower.

[0108] Each extraction tower is equipped with a nitrogen outlet pipe at the top, located on the top cover 4 or the top of the tower side wall. One end of the nitrogen outlet pipe is connected to the interior of the tower, and the other end is connected to a recovery tank via a pipe. The recovery tank is a sealed container with internal baffles or partitions to trap trace amounts of organic phase entrained in the nitrogen. The top of the recovery tank is equipped with an exhaust pipe to release the purified nitrogen into the atmosphere; the bottom of the recovery tank is equipped with a drain pipe to discharge the recovered organic phase for recycling.

[0109] The working principle of the nitrogen-assisted system is as follows: When the flow rate of a certain phase is insufficient, the nitrogen source is turned on. After the nitrogen is regulated by the pressure reducing valve, it enters the tower body from the nitrogen inlet pipe at the bottom of the tower. During the upward flow in the tower, it carries the organic phase upward. The nitrogen carrying a trace amount of organic phase is discharged from the nitrogen outlet pipe at the top of the tower and enters the recovery tank. In the recovery tank, gas and liquid are separated, and the organic phase is deposited at the bottom of the recovery tank. The purified nitrogen is discharged from the exhaust pipe at the top of the recovery tank.

[0110] Working relationship between components (a) The coordination relationship of dual filtration The filter holes (first-stage filtration) of the liquid extraction tube 14 and the filter through holes (second-stage filtration) of the dividing plate 13 are spatially connected in series and functionally complementary: First-stage filtration (liquid extraction pipe 14): The filter holes or filter screen at the inlet end of the liquid extraction pipe 14 have a diameter of 1~5mm, which intercepts large solid particles with a diameter ≥1mm when extracting the liquid phase. The advantages of this stage of filtration are high interception efficiency and large throughput, but it is difficult to intercept fine particles.

[0111] Second-stage filtration (segmentation plate 13): The pore size of the filter holes on the segmentation plate 13 is 0.5~3mm. When the liquid phase passes through the segmentation plate 13, it intercepts residual fine impurities (particle size ≥0.5mm) that the suction pipe filtration failed to intercept. The advantage of this stage of filtration is high interception accuracy, but the throughput is relatively small.

[0112] The two-stage filtration system forms a hierarchical relationship of "large pores first, small pores later," which enables graded interception and step-by-step purification of solid impurities. Large particles of impurities are intercepted by the liquid extraction pipe 14, preventing them from clogging the fine filter holes of the dividing plate 13. Fine impurities are intercepted by the dividing plate 13, preventing them from entering the next stage of the tower and the packing layer. The two-stage filtration works together to reduce the amount of solid impurities entering the packing layer from the source, forming a complete anti-clogging system of "source interception + end discharge" with the detachable flange slag discharge structure.

[0113] (II) The working relationship between the dual-mode top cover and the nitrogen-assisted system In the second working state (screwed into the hollow connector as an auxiliary feed channel), the second threaded hole 44 of the top cover 4 can introduce a small amount of conditioning agent into the tower without stopping the machine or depressurizing. When nitrogen is introduced into the nitrogen auxiliary system, causing pressure fluctuations in the tower, the opening of the second threaded hole 44 does not affect the overall compression ratio of the sealing ring 43 because the main bolt in the first threaded hole 41 provides the basic pre-tightening force for the top cover 4. This ensures the reliability of the seal.

[0114] Meanwhile, the trace amount of regulator introduced through the second threaded hole 44 is rapidly dispersed in the tower under the influence of nitrogen gas flow, achieving a rapid response to phase imbalance. This combination of "top cover fine-tuning feeding + nitrogen-assisted dispersion + main bolt pressure sealing" enables the entire extraction system to complete fine control without stopping the machine or depressurizing, significantly improving the system's operational stability and adaptability.

[0115] Example: The complete working process of the device of the present invention will be described below with reference to specific operating procedures.

[0116] (a) Start-up preparation The operator first checks whether the top cover 4 of each extraction tower (1, 2, 3) is fastened to the flange on the tower body through the bolts in the first threaded hole 41 and the second threaded hole 44, whether the sealing ring 43 is intact and embedded in the groove 42, confirms that the valves on each connecting pipe 15 are in the closed state, cleans the filter screen of the liquid extraction pipe 14 and installs it on the liquid inlet end of the liquid extraction pipe 14, and checks whether the filter through holes on the dividing plate 13 are unobstructed.

[0117] (ii) Feeding and Extraction Washing Start the feed pump and introduce the raw material acid leaching solution containing tantalum and niobium (total oxide concentration 105.83 g / L, HF 2.0 mol / L, H2SO4 1.5 mol / L) and the extractant (90% 2-octanol) into the bottom of the first extraction tower 1 from the first side wall feed inlet 12, respectively.

[0118] Meanwhile, low-concentration primary wash water is introduced from the wash water inlet at the top of the first extraction tower 1, and acid-adjusting solution is introduced from the acid-adjusting solution inlet in the middle of the first extraction tower 1 (located above the dividing plate 13).

[0119] Inside the first extraction tower 1, the heavy liquid (aqueous phase, including primary wash water and acid conditioning solution) flows from top to bottom as a continuous phase, while the light phase (organic phase) moves from bottom to top as a dispersed phase. The low-concentration primary wash water comes into contact with the organic phase and passes through the upper packing layer, where it mixes with the acid conditioning solution at the dividing plate 13. The mixture continues to flow downwards, coming into contact with the organic phase and passing through the lower packing layer.

[0120] During the liquid flow process, the liquid extraction pipe 14 intercepts large solid impurities through the filter screen (2mm aperture) at its inlet end when it draws in the liquid (first-stage filtration); when the liquid phase passes through the dividing plate 13, the filter through holes (1mm aperture) on the dividing plate trap residual fine impurities (second-stage filtration). The two-stage filtration together ensure that the content of solid impurities in the liquid phase entering the subsequent tower is greatly reduced.

[0121] The residual liquid after extraction and washing is discharged from the system through the first heavy liquid outlet 11. The loaded organic phase enters the second extraction column 2 from the top of the first extraction column 1 via the connecting pipe 15.

[0122] (III) Back-extraction of niobium The loaded organic phase enters from the bottom of the second extraction tower 2 and flows upwards. The anti-niobium agent (0.5 mol / L, H2SO4) enters the second extraction tower 2 through the side wall port 22 and flows downwards. The two phases contact countercurrently in the packing layer, and the niobium in the organic phase is back-extracted to the aqueous phase. The high-purity niobium solution is discharged from the bottom port 23 and sent to the subsequent process for producing high-purity niobium oxide. The organic phase containing only tantalum enters the third extraction tower 3 through the top pipe 24 and connecting pipe 15.

[0123] (iv) Back-extraction of tantalum The organic phase containing only tantalum enters from the bottom of the third extraction tower 3 and flows from bottom to top. The anti-tantalum agent (3.0 mol / L, H2SO4) enters the third extraction tower 3 from the feed inlet 32 ​​on the second side wall and flows from top to bottom. The two phases come into countercurrent contact in the packing layer. The tantalum in the organic phase is back-extracted to the aqueous phase. The high-purity tantalum solution is discharged from the outlet 31 of the second heavy liquid and sent to the subsequent process for producing high-purity tantalum oxide. The blank organic phase is discharged from the top of the third extraction tower 3 and recycled back to the first extraction tower 1 for continued use.

[0124] (v) Nitrogen-assisted regulation During operation, operators observe the position and flow rate of the two-phase interface through sight glasses or online instruments in each tower. When the flow rate of the organic phase in the second extraction tower 2 is found to be insufficient, the nitrogen source is turned on. After the nitrogen is regulated to 0.2MPa by the pressure reducing valve, it enters the tower body from the nitrogen inlet pipe at the bottom of the second extraction tower 2, promoting the upward movement of the organic phase. The nitrogen carries a trace amount of organic phase and is discharged from the nitrogen outlet pipe at the top of the tower, entering the recovery tank for gas-liquid separation. The organic phase is deposited at the bottom of the recovery tank for recovery, and the purified nitrogen is discharged from the exhaust pipe at the top of the recovery tank.

[0125] (vi) Operation monitoring and fine-tuning During system operation, if a trace amount of regulator (such as defoamer, surfactant, etc.) needs to be introduced into a certain tower, the operator unscrews the fastening bolt in the second threaded hole 44, screws in the hollow connector and connects the regulator supply pipeline. Without stopping the machine or depressurizing, the trace amount of regulator is introduced into the tower through the second threaded hole 44. After the introduction is completed, the hollow connector is unscrewed, the fastening bolt is screwed in again, and the first working state is restored. Throughout the entire operation, since the main bolt in the first threaded hole 41 always maintains the preload, the compression state of the sealing ring 43 is not affected, and the tower top seal is reliable.

[0126] (vii) Shutdown and Cleanup After the system has been running for a certain period of time (e.g., 3-6 months), it needs to be shut down for cleaning. The operator first stops the feeding and empties the material in each tower. Then, the equipment flanges below the light liquid inlet and above the heavy liquid inlet of each tower are removed. After opening the upper and lower flanges, the bulk packing material in the tower is discharged from the bottom of the tower body under the action of gravity, along with the trapped solids. The operator cleans or replaces the discharged packing material, reinstalls it into the tower body, and installs the flanges to restore the tower to use. The entire process can be completed by one worker in one day.

[0127] Furthermore, the apparatus may be illustrated in block diagram form to avoid obscuring one or more embodiments of this specification, and this also takes into account the fact that the details of implementation of these block diagram apparatuses are highly dependent on the platform on which one or more embodiments of this specification will be implemented (i.e., such details should be fully within the understanding of those skilled in the art). While specific details (e.g., circuitry) have been set forth to describe exemplary embodiments of this disclosure, it will be apparent to those skilled in the art that one or more embodiments of this specification may be implemented without these specific details or with variations thereof.

[0128] Therefore, these descriptions should be considered illustrative rather than restrictive.

[0129] Although the present disclosure has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0130] One or more embodiments of this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification should be included within the scope of protection of this disclosure.

Claims

1. An extraction tower device specifically for producing high-purity tantalum oxide, comprising a first extraction tower (1), a second extraction tower (2), and a third extraction tower (3) connected in series, characterized in that: The first extraction tower (1) is used to extract and wash the feed liquid containing tantalum and niobium and discharge the residual liquid. The bottom of the tower is provided with a first heavy liquid outlet (11), the side wall of the tower is provided with a first side wall feed inlet (12), and the tower is provided with a dividing plate (13) and a liquid extraction pipe (14). The second extraction tower (2) is used to back-extract niobium from the organic phase from the first extraction tower. It has a bottom port (23) at the bottom and a top pipe (24) at the top. The third extraction tower (3) is used to back-extract tantalum from the organic phase from the second extraction tower, and a second heavy liquid outlet (31) is provided at the bottom of the tower; the towers are connected by a connecting pipe (15).

2. The extraction column apparatus of claim 1, wherein: The dividing plate (13) has a filter through hole, and the pipe wall or opening of the liquid extraction pipe (14) has a filter hole. The dividing plate and the liquid extraction pipe form a two-stage filtration structure.

3. The extraction tower equipment according to claim 1, characterized in that: Each extraction tower is provided with a top cover (4), and the top cover (4) is provided with a first threaded hole (41) and a second threaded hole (44). The top cover (4) is provided with a groove (42), and a sealing ring (43) is provided in the groove. An inner hole (45) is provided in the center of the top cover.

4. The extraction tower equipment according to claim 3, characterized in that: The second threaded hole (44) has a dual-mode working state; In the first working state, screw in the fastening bolts to engage with the first threaded hole (41) to fix the top cover to the tower flange; In the second working state, the hollow connector is screwed in as an auxiliary feeding channel independent of the inner hole (45).

5. The extraction tower equipment according to claim 1, characterized in that: Each extraction tower is equipped with a flange located below the light liquid inlet and above the heavy liquid inlet.

6. The extraction tower equipment according to claim 1, characterized in that: It also includes a washing mechanism (5), which is provided with a first drain port (51), a second drain port (52), a side pipe (53) and an inlet pipe (54).

7. A continuous extraction process using the extraction tower equipment described in any one of claims 1-6, characterized in that... Includes the following steps: The feed solution containing tantalum and niobium and the extractant are introduced into the first extraction tower (1), and countercurrent extraction and washing are performed with the heavy liquid as the continuous phase and the light phase as the dispersed phase to obtain the loaded organic phase; The loaded organic phase is introduced into the second extraction tower (2) and contacted countercurrently with the anti-niobium agent to obtain an organic phase containing only tantalum; An organic phase containing only tantalum is introduced into the third extraction tower (3) and contacted countercurrently with an anti-tantalum agent to obtain a high-purity tantalum solution.

8. The continuous extraction process according to claim 7, characterized in that: In the first extraction tower (1), the low-concentration primary wash water comes into contact with the organic phase and passes through at least one packing layer before being mixed with the acid-adjusting solution and continuing to come into contact with the organic phase.

9. The continuous extraction process according to claim 7, characterized in that: When the flow rate of a certain phase in any tower is insufficient, nitrogen is introduced to promote the upward movement of the organic phase. The nitrogen is then discharged after recovering the entrained organic phase in the recovery tank.

10. The continuous extraction process according to claim 7, characterized in that: The extractant is a 2-octanol system, with a 2-octanol volume fraction of 85%~100%. The anti-niobium agent is 3~3.5 mol / L pure water; the anti-tantalum agent is 2.5~3.5 mol / L dilute sulfuric acid.

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