A device and method for preparing high-purity metal by vacuum distillation and bidirectional step condensation

Abstract

A device and method for preparing high-purity metals by vacuum distillation and bidirectional step condensation, the device comprising an atmosphere control device, a vacuum distillation device, a charging device, an intelligent control device, and an exhaust gas treatment device. The atmosphere control device comprises a nitrogen bottle and a control valve located above the bottle mouth for controlling the opening and closing of the nitrogen bottle. The vacuum distillation device comprises a vacuum distillation device and a vacuum pump connected to the vacuum distillation device via a pipeline. The charging device is located in the middle of the vacuum distillation device, and the intelligent control device is connected to the vacuum distillation device. The exhaust gas treatment device comprises an impurity removal device. The vacuum distillation device is provided with a plurality of heaters, which are arranged in parallel along the length direction of the charging device and the condensation zone on both sides of the vacuum distillation device. The present invention also includes a method for preparing high-purity metals using the device. The device of the present invention has a simple structure, is not restricted by the gravity field, is convenient for sampling, and has high impurity removal efficiency.

Description

Technical Field

[0001] The present invention relates to a device and method for preparing highly purified rare metals, and in particular to a device and method for preparing highly purified metals by vacuum distillation and bidirectional step condensation. Background Art

[0002] With the rapid development of strategic emerging industries such as precision electronics, aerospace, modern communications, and photovoltaic semiconductors, the demand for high-purity metals is growing. High-purity metals, due to their excellent physical and chemical properties, play a vital role in these fields. For example, high-purity tellurium, due to its exceptional thermoelectric, optical, physical, and thermal properties, is widely used in specialty alloys, high-end specialty steels, semiconductors, and battery materials, significantly improving the performance and quality of these materials.

[0003] To date, the main methods for preparing high-purity metals are electrolysis, zone melting and vacuum distillation. The purity of metals produced by electrolysis is generally not high; the production efficiency of zone melting is low; and the vacuum distillation method has a short process, low consumption, and no pollution to the environment. It is a clean and green high-purity metal preparation process. It is a hot topic in metal purification research and the main method widely used in industrial production. This technology is particularly suitable for the purification of low-melting-point metals and can effectively separate and collect the main metal and impurity elements. However, in the process of preparing high-purity metals by vacuum distillation, there are still challenges such as difficulty in reducing impurity content, unclear impurity migration mechanism, and limited improvement in production efficiency. 。

[0004] The fractionation mechanism of vacuum distillation technology primarily relies on differences in the saturated vapor pressures of substances, a difference that directly impacts the effectiveness and efficiency of purification. It can be said that saturated vapor pressure is a key factor influencing the effectiveness and efficiency of vacuum distillation purification. Taking tellurium as an example, the saturated vapor pressures of tellurium and impurity metals are calculated to assess whether different impurities can be separated from tellurium. Under vacuum and high-temperature conditions, the saturated vapor pressure P of pure metals can be calculated using the Clausius-Clapeyron equation. The results are shown in Table 1 below.

[0005] Table 1 Saturated vapor pressure of tellurium and impurities at various temperatures

[0006]

[0007]

[0008] At temperatures between 550°C and 650°C, the saturated vapor pressures of tellurium and some impurity elements differ significantly, making it easier to separate tellurium from impurities during vacuum distillation. Therefore, the temperature is generally controlled between 550°C and 650°C in experiments and production. As shown in Table 1, in the 550°C to 650°C temperature range, impurities such as Na, Mg, Se, and As have similar saturated vapor pressures to tellurium, making their removal difficult using traditional vacuum distillation equipment and methods.

[0009] CN117821762A discloses a coupled device and method for producing high-purity metals using vacuum distillation and zone melting. This device can produce 6N high-purity metals from 2N raw materials. However, the device is equipped with multiple complex precision components and control systems, resulting in high manufacturing costs and difficult maintenance. Furthermore, the coupled vacuum distillation and zone melting technologies also result in high energy consumption.

[0010] CN117298634A discloses a vacuum distillation apparatus for preparing high-purity metals using vacuum gradient condensation. This apparatus utilizes 2N to 3N raw materials to produce 4N to 5N high-purity metals. This apparatus, a vertical distillation furnace, suffers from the fact that impurity migration during vacuum distillation of high-purity metals is easily affected by gravity, resulting in unstable impurity removal efficiency and unclear gradient condensation. Furthermore, due to the characteristics of some high-purity metals, this apparatus also presents drawbacks such as difficulty in sampling. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned prior art and provide a device for preparing high-purity metals by vacuum distillation bidirectional cascade condensation with simple structure, no gravity field restriction, convenient sampling and high impurity removal efficiency.

[0012] A further technical problem to be solved by the present invention is to provide a method for preparing high-purity metal using the device for preparing high-purity metal by vacuum distillation and bidirectional step condensation.

[0013] The technical solution adopted by the present invention to solve its technical problems is: a device for preparing high-purity metals by vacuum distillation and bidirectional cascade condensation, including an atmosphere control device, a vacuum distillation device and its control device, and a charging device. The atmosphere control device includes a nitrogen bottle and a control valve 1 located above the bottle mouth for controlling the opening and closing of the nitrogen bottle. The vacuum distillation device includes a shell, a vacuum distiller installed in the shell, and a vacuum pump located outside the shell and connected to the vacuum distillation device through a pipeline. The charging device is located in the middle of the vacuum distillation device. The vacuum distillation device is horizontally divided into condensation zone 1, distillation zone and condensation zone 2 in sequence by partitions. Condensation zone 1 and condensation zone 2 are located on both sides of the distillation zone. Condensation zone 1 and condensation zone 2 are respectively connected to the distillation zone by connecting valves. The connecting channel 1 is connected to the connecting channel 2, and the connecting channel 1 is composed of a connecting pipe and a connecting port 1 which can be switched on and off and is provided at the end of the connecting pipe; the connecting channel 2 is composed of a connecting pipe 2 and a connecting port 2 which can be switched on and off and is provided at the second end of the connecting pipe; the distillation zone is provided with two distillation graphite boats, namely the first distillation graphite boat and the second distillation graphite boat, the condensation zone 1 and the condensation zone 2 are respectively provided with a first-stage condensation graphite boat and a second-stage condensation graphite boat, a plurality of heaters are provided on both sides of the condensation zone 1, the distillation zone and the condensation zone 2, and the plurality of heaters are arranged in parallel along the length direction of the charging device and the distillation zone, the condensation zone 1 and the condensation zone 2; an exhaust gas treatment device is also provided outside the shell of the vacuum distillation device; the intelligent control device is electrically connected to the plurality of heaters, the connecting port 1 and the connecting port 2 respectively.

[0014] Furthermore, the exhaust gas treatment device includes an impurity removal device, which is equipped with filter cotton and exhaust gas treatment liquid, and is used to collect metal particles and impurity gases volatilized from the vacuum distillation device, thereby facilitating the production of high-purity metals.

[0015] Furthermore, the length of each heater is 120 to 180 mm, the horizontal parallel spacing of each heater in condensation zone 1, distillation zone and condensation zone 2 is 8 to 12 mm, and the horizontal parallel spacing between condensation zone 1, distillation zone and condensation zone 2 is 15 to 20 mm.

[0016] Furthermore, the first-stage condensed graphite boat and the second-stage condensed graphite boat are both three-stage condensed graphite boats.

[0017] Furthermore, a partition is provided between the first distillation graphite boat and the second distillation graphite boat.

[0018] Furthermore, the lengths of the three stepped platforms of the three-step condensation graphite boat one are 50-70 mm, 370-500 mm, and 80-100 mm from right to left, respectively, and the heights of each step from bottom to top are 0 mm, 5-10 mm, and 10-20 mm, respectively; the lengths of the distillation graphite boat one and the distillation graphite boat two are 500-670 mm; the lengths of the three stepped platforms of the three-step condensation graphite boat two are 50-70 mm, 370-500 mm, and 80-100 mm from left to right, respectively, and the heights of each step from bottom to top are 0 mm, 5-10 mm, and 10-20 mm, respectively; the widths of the stepped platforms of the stepped condensation graphite boat and the width of the distillation graphite boat are adapted to the inner wall of the shell of the vacuum distillation apparatus.

[0019] Furthermore, the main function of the intelligent control device is to control the switch of the heater of the vacuum distillation device and the speed and amplitude of heating and cooling. It can also control the opening and closing of the connection port between the distillation graphite boat and the stepped condensation zone.

[0020] Furthermore, the control valve 1 is used to control the opening and closing of the nitrogen bottle, and is connected to the left side of the vacuum distillation device through a gas pipeline; the purity of the nitrogen is 6N level; the exhaust gas treatment device is connected to the right side of the vacuum distillation device through the control valve 2.

[0021] Furthermore, the tail gas treatment device is equipped with filter cotton and tail gas treatment liquid.

[0022] By adopting the above technical solution, the device of the present invention has a high degree of mechanical automation, which helps to exhaust the air inside the device and prevent air from contaminating the raw materials. At the same time, it produces a better distillation effect and helps to obtain high-purity metal.

[0023] Furthermore, a preferred embodiment of the apparatus of the present invention includes four heaters in each of the two condensing zones and four heaters in the distillation zone. Each heater and the connection ports of the connecting channels between the distillation zone and the condensing zone are electrically connected to an intelligent control device. Each heater can independently control the temperature rise and fall amplitude and speed through the intelligent control device, and the opening and closing of each connection port can also be independently controlled. By sharing some equipment and components, the vacuum distillation apparatus can operate rationally. The distillation operation is located in the distillation zone, where the heaters provide heat to evaporate the raw materials. The raw material vapor enters the condensation zone through the connection ports of the connecting channel and condenses there. During the distillation process, a partition is installed between the first and second distillation graphite boats to prevent cross-contamination between the raw materials.

[0024] Furthermore, another embodiment of the device of the present invention is to set up three heaters, wherein the first heater and the third heater correspond to the stepped condensation graphite boat one and the stepped condensation graphite boat two placed in the condensation zone one and the condensation zone two respectively, and the first heater and the third heater are mainly used to control the rising and falling amplitude and speed of the heating temperature of the condensation zone one and the condensation zone two through the intelligent control device; the second heater corresponds to the two distillation graphite boats set up in the distillation zone, and the function of the second heater is to control the rising and falling amplitude and speed of the heating temperature of the distillation zone through the intelligent control device, which is helpful to obtain high-purity metal products; the raw material located in the distillation graphite boat one is condensed in the stepped condensation zone one through the connection port one controlled by the intelligent control device, and the raw material located in the distillation graphite boat two is condensed in the stepped condensation zone two through the connection port two controlled by the intelligent control device.

[0025] The present invention further solves the technical problem by adopting a technical solution that is a method for preparing high-purity metal by vacuum distillation and bidirectional step condensation using the device, comprising the following steps:

[0026] (S1) weighing raw materials, loading them into a first distillation graphite boat and a second distillation graphite boat, and adjusting the first distillation graphite boat and the second distillation graphite boat to the middle position of the vacuum distillation apparatus;

[0027] (S2) Open the connection port 1 and the connection port 2, and introduce nitrogen into the vacuum distillation apparatus to remove air impurities in the apparatus; close the control valve 1 and the control valve 2; use a vacuum pump to reduce the vacuum degree in the vacuum distillation apparatus to 10 -4 Pa below; close connector 1 and connector 2;

[0028] (S3) According to the saturated vapor pressure of the raw materials, the distillation temperature and time of the distillation zone, and the condensation temperature and time of the step condensation zone 1 and the step condensation zone 2 are set by the intelligent control device, and then the heaters are started to heat the first distillation graphite boat and the second distillation graphite boat, as well as the first step condensation graphite boat and the second step condensation graphite boat. After the distillation and condensation in the distillation zone, the condensation zone 1, and the condensation zone 2 are respectively completed, the control valve 1, the control valve 2, the connection port 1, and the connection port 2 are opened;

[0029] (S4) stopping heating, cooling to room temperature, introducing nitrogen, and restoring the vacuum distillation apparatus to normal pressure;

[0030] (S5) taking out the products in the first-stage condensed graphite boat and the second-stage condensed graphite boat respectively; the product in the middle stage platform portion of the staged condensed graphite boat is retained;

[0031] (S6) Using the products in the step platforms on both sides of the first-stage condensed graphite boat and the second-stage condensed graphite boat as raw materials, repeating steps S1 to S5 to achieve continuous production of high-purity metal.

[0032] Furthermore, when nitrogen is introduced, the nitrogen flow rate is regulated to be 0.8 to 1.2 L / min, and the ventilation time is 30 min to 60 min.

[0033] Furthermore, in step S1, the purity of the raw material is 5N, and the length of the raw material is 50-80 mm shorter than the length of the distillation graphite boat 1 and the distillation graphite boat 2.

[0034] Furthermore, during the condensation process, a stepped cooling method is adopted: first, a higher temperature is set so that impurities with similar saturated vapor pressure are first volatilized to the outermost graphite boat platform of the stepped condensation graphite boat; after maintaining it for a period of time, the condensation temperature is appropriately lowered so that the matrix metal vapor is evenly condensed on the middle platform of the stepped condensation graphite boat; the specific values ​​of the two condensation temperatures and the specific condensation time are determined according to the saturated vapor pressure of the raw material matrix metal.

[0035] Furthermore, during the distillation process, a step-by-step heating method is adopted: first, a lower temperature is set, and after maintaining it for a period of time, the distillation temperature is appropriately increased and continued for a period of time until the raw material metal is distilled; the specific data of the two-stage distillation temperature settings and the specific duration are also determined according to the saturated vapor pressure of the raw material base metal.

[0036] The amount of raw materials charged in step S1 is determined according to the volume of the distillation graphite boat.

[0037] Because some impurity metals in high-purity metals have a saturated vapor pressure similar to that of the base metal, these impurity metals are difficult to effectively separate from the base metal during the distillation process. Therefore, during the distillation and condensation process, a higher temperature is first set to allow impurities with similar saturated vapor pressures to evaporate to the outermost graphite boat platform of the stepped condensation graphite boat. After maintaining this temperature for a period of time, the distillation and condensation temperatures are appropriately lowered to allow the base metal to condense evenly in the middle of the stepped condensation graphite boat. After all raw materials have been distilled, the condensation zone is continued to be heated at the original condensation temperature, allowing impurities with higher evaporation temperatures and less volatility to evaporate to the inner side of the stepped condensation graphite boat. Therefore, the product obtained from the middle stepped platform of the stepped condensation graphite boat has a higher purity, while the products from the stepped platforms on both sides have a lower purity.

[0038] Since the raw materials contain a large amount of main metal and a small amount of impurity metal, although some of the raw materials will be condensed on the stepped platforms of the leftmost and rightmost stepped condensation graphite boats, their impurity content is relatively high. Therefore, in step S6, they are used as raw materials again, and steps S1 to S5 are repeated for secondary processing to further purify the base metal and save the raw metal.

[0039] Furthermore, in step S1, the purity of the raw material is 4N, and the length of the raw material is 50-80 mm shorter than the length of the first distillation graphite boat and the second distillation graphite boat.

[0040] The apparatus for preparing high-purity metals by vacuum distillation and bidirectional cascade condensation of the present invention is a bidirectional cascade condensation apparatus for preparing high-purity metals. It can effectively remove impurities by cascade condensation, clarify the impurity migration mechanism, and achieve simultaneous vacuum distillation of two batches of raw materials within the same apparatus, thereby achieving high production efficiency. It is suitable for the preparation of a variety of high-purity metals.

[0041] Compared with the prior art, the present invention has the following beneficial effects: (1) Bidirectional step condenser design: The device of the present invention adopts a bidirectional step condenser design, and achieves step condensation impurity removal through step condensation graphite boat 1 and step condensation graphite boat 2. This design helps to more effectively separate impurities and base metal, and improve the purity of the metal product produced; (2) Independent temperature-controlled heaters are set: The condensation zone and distillation zone in the device are respectively provided with multiple heaters, and each heater can achieve independent temperature control; this design allows the distillation and condensation processes to be controlled more accurately, thereby improving the production efficiency and quality of high-purity metal; (3) Application of intelligent control device: Through the intelligent control device, the switch and heating and cooling speed and amplitude of each heater can be controlled separately, and the opening and closing of each connection port can be controlled separately, which improves the degree of automation of operation, reduces errors in human operation, and helps to improve production efficiency and safety; (4) The filter cotton and tail gas treatment liquid in the impurity removal device of the tail gas treatment device are used to collect metal particles and impurity gases volatilized from the vacuum distillation device, which helps to obtain high-purity metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic structural diagram of an embodiment of a device for preparing high-purity metals by vacuum distillation and bidirectional step condensation according to the present invention.

[0043] Figure 2 It is an enlarged schematic diagram of the structure of the stepped condensation graphite boat in the embodiment of the device of the present invention.

[0044] Figure 3 It is a structural schematic diagram of an existing horizontal vacuum distillation furnace.

[0045] In the figure: 1. Nitrogen cylinder; 2. Control valve 1; 3. Vacuum distillation device; 31. Condensation zone 1; 32. Distillation zone 1; 33. Condensation zone 2; 311. Heater 1; 312. First-stage condensation graphite boat; 321. Heater 2; 322. Partition; 323. First distillation graphite boat; 324. Second distillation graphite boat; 331. Heater 3; 332. Second-stage condensation graphite boat; 34. Connecting channel 1, 341. Connecting port 1; 342. Connecting pipe 1; 35. Connecting channel 2, 351. Connecting pipe 2; 352. Connecting port 2; 4. Intelligent control device; 5. Vacuum pump; 6. Control valve 2; 7. Exhaust gas treatment device. DETAILED DESCRIPTION

[0046] The following is a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings and examples. These examples should not be used to limit the scope of patent protection of the present invention.

[0047] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the examples of the present invention were purchased from the market or prepared by known existing methods.

[0048] Example 1

[0049] Reference Figure 1 、 2, the device for preparing high-purity metal by vacuum distillation and bidirectional step condensation in this embodiment includes an atmosphere control device, a vacuum distillation device 3 and its control device, and a charging device, the atmosphere control device includes a nitrogen bottle 1 and a control valve 2 located above the bottle mouth for controlling the opening and closing of the nitrogen bottle 1, the vacuum distillation device 3 includes a shell, a vacuum distiller installed in the shell, and a vacuum pump 5 located outside the shell and connected to the vacuum distillation device 3 through a pipeline, the charging device is located in the middle of the vacuum distillation device 3, and the vacuum distillation device 3 is horizontally divided into condensation zone 1 31, distillation zone 32 and condensation zone 2 33 in sequence by partitions, condensation zone 1 31 and condensation zone 2 33 are located on both sides of the distillation zone 32, and condensation zone 1 31 and distillation zone 32 are connected by connecting channel 1 34 and connecting channel 2 35 respectively, and connecting channel 1 34 is connected by connecting pipe 341 and connecting channel 35 located at the bottom of the distillation zone 32. The end of the tube 341 is composed of a connecting port 1 342 that can be switched on and off; the connecting channel 2 35 is composed of a connecting pipe 2 351 and a connecting port 2 352 that can be switched on and off provided at the end of the connecting pipe 351; the distillation zone 32 is provided with two distillation graphite boats, namely a first distillation graphite boat 323 and a second distillation graphite boat 324, the condensation zone 1 31 and the condensation zone 2 33 are respectively provided with a first-stage condensation graphite boat 312 and a second-stage condensation graphite boat 332, and multiple heaters 311, 321, 331 are provided on both sides of the condensation zone 1 31, the distillation zone 32 and the condensation zone 2 33, and the multiple heaters are arranged side by side along the length direction of the charging device and the distillation zone 32, the condensation zone 1 31 and the condensation zone 2 33; an exhaust gas treatment device 7 is also provided outside the shell of the vacuum distillation device 3; the intelligent control device 4 is electrically connected to the multiple heaters 311, 321, 331, the connecting port 1 341 and the connecting port 2 352.

[0050] A partition 322 is provided between the first distillation graphite boat 323 and the second distillation graphite boat 324 .

[0051] The exhaust gas treatment device 7 includes an impurity removal device; the impurity removal device is equipped with filter cotton and exhaust gas treatment liquid; it is used to collect metal particles and impurity gases volatilized from the vacuum distillation device, which helps to obtain high-purity metal.

[0052] In this embodiment, the condensation zone 1, the distillation zone and the condensation zone 2 of the vacuum distillation device 3 are each provided with 4 heaters, each heater is 150 mm long, the horizontal parallel spacing of each heater in the condensation zone 1, the distillation zone and the condensation zone 2 is 10 mm, and the horizontal parallel spacing between the condensation zone 1, the distillation zone and the condensation zone 2 is 15 mm.

[0053] In this embodiment, the stepped condensation graphite boats are all three-step condensation graphite boats; the lengths of the three stepped platforms of the three-step condensation graphite boat 1 312 are 60 mm, 450 mm, and 90 mm from right to left, and the heights of each step from bottom to top are 0 mm, 5 mm, and 10 mm, respectively; the lengths of the distillation graphite boat 1 323 and the distillation graphite boat 2 324 are 580 mm, respectively; the lengths of the three stepped platforms of the three-step condensation graphite boat 2 332 are 60 mm, 450 mm, and 90 mm from left to right, and the heights of each step from bottom to top are 0 mm, 5 mm, and 10 mm, respectively; the purity of the materials of the graphite boats and the impurities are less than 3 ppm.

[0054] The intelligent control device 4 is used to control the switching of each heater in the vacuum distillation device 3 and the speed and amplitude of heating and cooling. It can also control the opening and closing of the connection port 1 341 and the connection port 2 352 .

[0055] The control valve 1 2 is used to control the opening and closing of the nitrogen bottle 1, and is connected to the left side of the vacuum distillation device 3 through a gas pipeline; the purity of the nitrogen is 6N level; the tail gas treatment device 7 is connected to the right side of the vacuum distillation device 3 through the control valve 2 6.

[0056] The intelligent control device 4 is used to control the switches of the heaters of the vacuum distillation device 3 and the amplitude and speed of temperature increase and decrease. It can also control the opening and closing of the connection port 1 341 and the connection port 2 352 .

[0057] Example 2

[0058] An embodiment of a method for preparing high-purity tellurium metal using the apparatus for preparing high-purity metal by vacuum distillation and bidirectional step condensation comprises the following steps:

[0059] (S1) Weighing tellurium material, loading it into the first distillation graphite boat 323 and the second distillation graphite boat 324, and adjusting the positions of the first distillation graphite boat 323 and the second distillation graphite boat 324 in the vacuum distillation apparatus 3;

[0060] (S2) Open the connection port 1 341 and the connection port 2 352, and introduce nitrogen into the vacuum distillation apparatus 3 to remove air impurities in the apparatus; close the control valve 1 2 and the control valve 2 6; use the vacuum pump 5 to reduce the vacuum degree in the vacuum distillation apparatus 3 to 10 -4 Pa below; close the connection port 1 341 and the connection port 2 352;

[0061] (S3) Activating the intelligent control device 4, turning on the heater 1 311, the heater 2 321, and the heater 3 331 via the intelligent control device 4 to start heating and distillation. After the distillation and condensation in the distillation zone 32, the condensation zone 1 31, and the condensation zone 2 33 are completed, respectively, the control valve 1 2, the control valve 2 6, the connection port 1 341, and the connection port 2 352 are opened.

[0062] (S4) turning off each heater through the intelligent control device 4, stopping heating, cooling to room temperature, introducing nitrogen, and restoring to normal pressure;

[0063] (S5) taking out the products from the first three-step condensation graphite boat 312 of condensation zone 1 and the second three-step condensation graphite boat 332 of condensation zone 2 respectively; retaining the products from the middle step platform portion of the three-step condensation graphite boat;

[0064] (S6) Using the products in the stepped platforms on both sides of the first three-step condensed graphite boat 312 and the second three-step condensed graphite boat 332 as raw materials, repeat steps S1 to S5 to achieve continuous production of high-purity tellurium.

[0065] In this embodiment, in step S1, the amount of tellurium material loaded is 1000 g; when nitrogen is introduced, the nitrogen flow rate is regulated to 1 L / min, and the ventilation time is 30 min; the distillation temperature of the distillation zone 32 is first set to 450°C, maintained for 180 min, and then set to 525°C, maintained for 270 min, and the condensation temperature of the step condensation zone 1 31 and the step condensation zone 2 33 is first set to 400°C, maintained for 180 min, and then set to 200°C, maintained for 270 min.

[0066] In this embodiment, the purity of the tellurium raw material used in step S1 is 4N, and the length of the tellurium raw material is 60 mm shorter than the lengths of the first distillation graphite boat 423 and the second distillation graphite boat 424 .

[0067] The obtained product was subjected to ICP-MS detection. The results are shown in Table 2. The purity of the product high-purity tellurium reached 99.9999672%, and the production cycle was 24 hours.

[0068] Table 2 Statistics of impurity content of high-purity tellurium obtained in Example 2 (unit: ppbw)

[0069] element Ag Al Cu Ca Mg Ni Pb Se Zn Fe Cd standard <10 <50 <10 <100 <50 <50 <50 <100 <100 <50 <50 Example 1 5 28 4 6 24 38 41 85 53 19 25

[0070] Example 3:

[0071] Example 3 Selenium was prepared using the apparatus described in Example 1, the method comprising the following steps:

[0072] (S1) Weighing selenium material, loading it into distillation graphite boat 1 323 and distillation graphite boat 2 324, and adjusting the positions of distillation graphite boat 1 323 and distillation graphite boat 2 324 in vacuum distillation apparatus 3;

[0073] (S2) Open the connection port 1 341 and the connection port 2 352, and introduce nitrogen into the vacuum distillation apparatus 3 to remove air impurities in the apparatus; close the control valve 1 2 and the control valve 2 6; use the vacuum pump 5 to reduce the vacuum degree in the vacuum distillation apparatus 3 to 10 -4 Pa below; close the connection port 1 341 and the connection port 2 352;

[0074] (S3) turning on the heater 321 to start heating and distillation. After the distillation and condensation in the distillation zone 32, the condensation zone 1 31, and the condensation zone 2 33 are respectively completed, opening the control valve 1 2, the control valve 2 6, the connection port 1 341, and the connection port 2 352;

[0075] (S4) stopping heating, cooling to room temperature, introducing nitrogen, and returning to normal pressure;

[0076] (S5) taking out the products in the three-step condensation graphite boat 1 312 and the three-step condensation graphite boat 2 332 respectively; the product in the middle part of the three-step condensation graphite boat is retained;

[0077] (S6) Using the products on both sides of the three-step condensation graphite boat 1 312 and the three-step condensation graphite boat 2 332 as raw materials, steps S1 to S5 are repeated to achieve continuous production of high-purity selenium.

[0078] In this embodiment, in the step S1, the amount of selenium material loaded is 1000 g; in the step S2, when the nitrogen is introduced, the nitrogen flow rate is regulated to 1 L / min, and the ventilation time is 30 min; in the step S3, the distillation temperature of the distillation zone 32 is first set to 220°C, maintained for 90 min, and then set to 450°C, maintained for 240 min, and the condensation temperature of the step condensation zone 1 31 and the step condensation zone 2 33 is first set to 200°C, maintained for 90 min, and then set to 100°C, maintained for 240 min.

[0079] In this embodiment, the purity of the selenium raw material in step S1 is 4N, and the length of the selenium raw material is 60 mm shorter than the length of the first distillation graphite boat 423 and the second distillation graphite boat 424 .

[0080] The obtained product was subjected to ICP-MS detection. The results are shown in Table 3. The purity of the product high-purity selenium reached 99.9999534%, and the production cycle was 24 hours.

[0081] Table 3 Statistics of impurity content of high-purity selenium obtained in Example 3 (unit: ppbw)

[0082] element Cu Ag Mg Ni Bi In Fe Cd Te Al Ti Pb standard <50 <50 <100 <50 <50 <50 <100 <50 <100 <50 <50 <50 Example 2 41 34 81 27 12 26 73 19 84 20 23 26

[0083] Example 4:

[0084] This embodiment uses the apparatus described in Example 1 to prepare indium, and the method includes the following steps:

[0085] (S1) Weighing indium material, loading it into distillation graphite boat 1 323 and distillation graphite boat 2 324, and adjusting the positions of distillation graphite boat 1 323 and distillation graphite boat 2 324 in vacuum distillation apparatus 3;

[0086] (S2) Open the connection port 1 341 and the connection port 2 352, and introduce nitrogen into the vacuum distillation apparatus 3 to remove air impurities in the apparatus; close the control valve 1 2 and the control valve 2 6; use the vacuum pump 5 to reduce the vacuum degree in the vacuum distillation apparatus 3 to 10 -4 Pa below; close the connection port 1 341 and the connection port 2 352;

[0087] (S3) turning on the heater 321 to start heating and distillation. After the distillation and condensation in the distillation zone 32, the condensation zone 1 31, and the condensation zone 2 33 are respectively completed, opening the control valve 1 2, the control valve 2 6, the connection port 1 341, and the connection port 2 352;

[0088] (S4) stopping heating, cooling to room temperature, introducing nitrogen, and returning to normal pressure;

[0089] (S5) taking out the products in the stepped condensation graphite boat 1 312 and the stepped condensation graphite boat 2 332 respectively; the product in the middle part of the stepped condensation graphite boat is retained;

[0090] (S6) Using the products on both sides of the stepped condensation graphite boat 1 312 and the stepped condensation graphite boat 2 332 as raw materials, steps S1 to S5 are repeated to achieve continuous production of high-purity indium.

[0091] In this embodiment, in the step S1, the amount of indium material loaded is 1000 g; in the step S2, when nitrogen is introduced, the nitrogen flow rate is regulated to 1 L / min, and the ventilation time is 30 min; in the step S,3, the distillation temperature of the distillation zone 32 is first set to 200°C, the distillation time is 80 min, and then set to 1000°C and maintained for 240 min, and the condensation temperature of the step condensation zone 1 31 and the step condensation zone 2 33 is first set to 850°C and maintained for 80 min, and then set to 700°C and maintained for 240 min.

[0092] In this embodiment, the purity of the indium raw material in step S1 is 4N, and the length of the indium raw material is 60 mm shorter than the length of the first distillation graphite boat 423 and the distillation graphite boat 424 .

[0093] The obtained product was subjected to ICP-MS detection. The results are shown in Table 4. The purity of the product high-purity indium reached 99.9999687%, and the production cycle was 24 hours.

[0094] Table 4 Statistics of impurity content of high-purity indium obtained in Example 4 (unit: ppbw)

[0095] element Fe Cu Pb Sn Cd Mg Si S standard <100 <100 <100 <300 <50 <100 <100 <100 Example 3 41 34 81 27 12 26 73 19

[0096] Comparative Example 1:

[0097] Comparative Example 1 Figure 3 Using the apparatus described in [1], tellurium material was first loaded into a horizontal vacuum distillation furnace. The vacuum pump was then activated to evacuate the furnace. Finally, the heating process was initiated. The distillation zone temperature was initially set to 450°C for 180 minutes, then to 525°C for 270 minutes. The condensation zone temperature was initially set to 400°C for 180 minutes, then to 200°C for 270 minutes. The impurity content of the distillation product was analyzed by ICP-MS, as shown in Table 5.

[0098] Table 5 Statistics of impurity content of high-purity tellurium obtained in Comparative Example 1 (unit: ppbw)

[0099] element Ag Al Cu Ca Mg Ni Pb Se Zn Fe Cd standard <10 <50 <10 <100 <50 <50 <50 <100 <100 <50 <50 Comparative Example 1 16 48 18 84 61 53 49 91 104 39 28

[0100] Comparative Example 2:

[0101] Comparative Example 2 uses Figure 3 Using the apparatus described in [1], selenium material was first loaded into a horizontal vacuum distillation furnace. The vacuum pump was then activated to evacuate the furnace. Finally, the heating process was initiated. The distillation zone temperature was initially set to 220°C for 90 minutes, then to 450°C for 240 minutes. The condensation zone temperature was initially set to 200°C for 90 minutes, then to 100°C for 240 minutes. The distillation product was analyzed for impurities using ICP-MS, as shown in Table 6.

[0102] Table 6 Statistics of impurity content of high-purity selenium obtained in Comparative Example 1 (unit: ppbw)

[0103] element Cu Ag Mg Ni Bi In Fe Cd Te Al Ti Pb standard <50 <50 <100 <50 <50 <50 <100 <50 <100 <50 <50 <50 Comparative Example 2 56 61 79 72 21 42 79 91 112 29 43 58

[0104] Comparative Example 3:

[0105] Comparative Example 3 Figure 3 Using the apparatus described in [1], indium material was first loaded into a horizontal vacuum distillation furnace. The vacuum pump was then activated to evacuate the furnace. Finally, the heating process was initiated. The distillation zone temperature was initially set to 200°C for 80 minutes, then to 1000°C and held for 240 minutes. The condensation zone temperature was initially set to 850°C for 80 minutes, then to 700°C for 240 minutes. The impurity content of the distillation product was analyzed by ICP-MS, as shown in Table 7.

[0106] Table 7 Statistics of impurity content of high-purity indium obtained in Comparative Example 3 (unit: ppbw)

[0107] element Fe Cu Pb Sn Cd Mg Si S standard <100 <100 <100 <300 <50 <100 <100 <100 Comparative Example 3 109 124 85 359 81 93 106 154

[0108] The purification effect of Examples 1 to 3 on 4N raw materials is significantly better than that of Comparative Examples 1 to 3, and the content of impurity elements meets the industry standard for high-purity metals. The purification device provided by the present invention can achieve the preparation of high-purity metals.

[0109] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A device for preparing high-purity metals by vacuum distillation and bidirectional step condensation, comprising an atmosphere control device, a vacuum distillation device (3) and its intelligent control device, and a charging device, wherein the atmosphere control device comprises a nitrogen bottle (1) and a control valve (2) disposed above the bottle mouth for controlling the opening and closing of the nitrogen bottle (1), the vacuum distillation device (3) comprises a shell, a vacuum distiller installed in the shell, and a vacuum pump (5) disposed outside the shell and connected to the vacuum distillation device (3) through a pipeline, the charging device being disposed inside the vacuum distillation device. In the middle of (3), the vacuum distillation device (3) is divided into condensation zone 1 (31), distillation zone (32) and condensation zone 2 (33) in turn by partitions. Condensation zone 1 (31) and condensation zone 2 (33) are located on both sides of distillation zone (32). Condensation zone 1 (31) and distillation zone (32) are connected by connecting channel 1 (34) and connecting channel 2 (35) respectively. Connecting channel 1 (34) is composed of connecting pipe 1 (342) and a connecting pipe 2 (35) provided on connecting pipe 1 ( The first connecting port (341) of the connecting channel (342) is openable and closed at the end thereof; the second connecting channel (35) is composed of a second connecting pipe (351) and a second connecting port (352) which is openable and closed at the end thereof; the distillation zone (32) is provided with two distillation graphite boats, namely a first distillation graphite boat (323) and a second distillation graphite boat (324); the first condensation zone (31) and the second condensation zone (33) are respectively provided with a first stage condensation graphite boat (312) and a second stage condensation graphite boat (332); the condensation A plurality of heaters (311, 321, 331) are provided on both sides of the first zone (31), the distillation zone (32), and the second condensation zone (33), and the plurality of heaters are arranged in parallel along the length direction of the charging device and the distillation zone (32), the first condensation zone (31), and the second condensation zone (33); an exhaust gas treatment device (7) is further provided outside the shell of the vacuum distillation device (3); the intelligent control device (4) is electrically connected to the plurality of heaters (311, 321, 331), the first connection port (341), and the second connection port (352); The first-stage condensed graphite boat (312) and the second-stage condensed graphite boat (332) are both three-stage condensed graphite boats; The intelligent control device (4) is used to control the switching of each heater in the vacuum distillation device (3) and the speed and amplitude of heating and cooling, and can also control the opening and closing of the connection port 1 (341) and the connection port 2 (352); The control valve 1 (2) is used to control the opening and closing of the nitrogen bottle (1) and is connected to the left side of the vacuum distillation device (3) through a gas pipeline; the purity of the nitrogen is 6N grade; the tail gas treatment device (7) is connected to the right side of the vacuum distillation device (3) through the control valve 2 (6).

2. The device for preparing high-purity metal by vacuum distillation and bidirectional cascade condensation according to claim 1, characterized in that: The length of each heater is 120~180mm, the horizontal parallel spacing between the heaters in the condensation zone 1 (31), the distillation zone (32) and the condensation zone 2 (33) is 8~12mm, and the horizontal parallel spacing between the condensation zone 1 (31), the distillation zone (32) and the condensation zone 2 (33) is 15~20mm.

3. The device for preparing high-purity metal by vacuum distillation and bidirectional cascade condensation according to claim 1 or 2, characterized in that: A partition (322) is provided between the first distillation graphite boat (323) and the second distillation graphite boat (324); the tail gas treatment device (7) is equipped with filter cotton and tail gas treatment liquid.

4. The device for preparing high-purity metal by vacuum distillation and bidirectional cascade condensation according to claim 3, characterized in that: The lengths of the three stepped platforms of the first-stage condensation graphite boat (312) are 50-70 mm, 370-500 mm, and 80-100 mm from right to left, respectively, and the heights of the steps from bottom to top are 0 mm, 5-10 mm, and 10-20 mm, respectively; the lengths of the first distillation graphite boat (323) and the second distillation graphite boat (324) are 500-670 mm; the lengths of the three stepped platforms of the second-stage condensation graphite boat (332) are 50-70 mm, 370-500 mm, and 80-100 mm from left to right, respectively, and the heights of the steps from bottom to top are 0 mm, 5-10 mm, and 10-20 mm, respectively; the widths of the stepped platforms of the stepped condensation graphite boat and the width of the distillation graphite boat are adapted to the inner wall of the shell of the vacuum distillation device (3).

5. A method for preparing high-purity metal by vacuum distillation and bidirectional step condensation using the apparatus according to any one of claims 1 to 4, characterized in that: The following steps are involved: (S1) weighing raw materials, loading them into a first distillation graphite boat (323) and a second distillation graphite boat (324), and adjusting the first distillation graphite boat (323) and the second distillation graphite boat (324) to the middle position of the vacuum distillation device (3); (S2) Open the connection port 1 (341) and the connection port 2 (352) through the intelligent control device (4), and introduce nitrogen into the vacuum distillation device (3) to remove air impurities in the device; close the control valve 1 (2) and the control valve 2 (6); use the vacuum pump (5) to reduce the vacuum degree in the vacuum distillation device (3) to 10 -4 Pa below; close the connection port 1 (341) and the connection port 2 (352); (S3) According to the saturated vapor pressure of the raw materials, the distillation temperature and distillation time of the distillation zone (32) and the condensation temperature and condensation time of the condensation zone 1 (31) and the condensation zone 2 (33) are set by the intelligent control device, and then the heaters are started to heat the first distillation graphite boat (323) and the second distillation graphite boat (324), and the first-stage condensation graphite boat (312) and the second-stage condensation graphite boat (332). After the distillation and condensation of the distillation zone (32), the condensation zone 1 (31) and the condensation zone 2 (33) are completed, the control valve 1 (2), the control valve 2 (6), the connection port 1 (341) and the connection port 2 (352) are opened; (S4) stopping heating, cooling to room temperature, introducing nitrogen, and restoring the vacuum distillation apparatus (3) to normal pressure; (S5) taking out the products in the first-stage condensed graphite boat and the second-stage condensed graphite boat respectively; the products in the middle stage platform portion of the staged condensed graphite boat are retained; (S6) Using the products in the step platforms on both sides of the first-stage condensed graphite boat and the second-stage condensed graphite boat as raw materials, repeating steps S1 to S5 to achieve continuous production of high-purity metal.

6. The method for preparing high-purity metal by vacuum distillation and bidirectional cascade condensation according to claim 5, characterized in that: When introducing nitrogen, adjust the nitrogen flow rate to 0.8~1.2L / min and the ventilation time to 30min~60min.

7. The method for preparing high-purity metal by vacuum distillation and bidirectional cascade condensation according to claim 5 or 6, characterized in that: In step S1, the purity of the raw material is 5N, and the length of the raw material is 50-80 mm shorter than the length of the first distillation graphite boat (323) and the second distillation graphite boat (324); During the condensation process, a higher temperature is first set to allow impurities with similar saturated vapor pressure to evaporate to the outermost graphite boat platform of the stepped condensation graphite boat; after maintaining it for a period of time, the condensation temperature is appropriately lowered to allow the base metal vapor to condense evenly on the middle platform of the stepped condensation graphite boat; the specific values ​​of the two condensation temperatures and the specific condensation time are determined according to the saturated vapor pressure of the raw material base metal.

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