Device and method for preparing high-purity metal through vacuum distillation and bidirectional stepped condensation

Abstract

The invention relates to a device and method for preparing high-purity metal through vacuum distillation and two-way cascade condensation, the device comprises an atmosphere control device, a vacuum distillation device, a charging device, an intelligent control device and a tail gas treatment device, the atmosphere control device comprises a nitrogen cylinder and a first control valve arranged above a bottle opening of the nitrogen cylinder and used for controlling opening and closing of the nitrogen cylinder; the vacuum distillation device comprises a vacuum distillation device and a vacuum pump connected with the vacuum distillation device through a pipeline, the charging device is arranged in the middle of the vacuum distillation device, and the intelligent control device is connected with the vacuum distillation device; the tail gas treatment device comprises an impurity removal device; the vacuum distillation device is provided with a plurality of heaters, and the heaters are arranged in parallel along the length directions of the charging device and the condensation areas on the two sides of the vacuum distillation device. The invention further comprises a method for preparing the high-purity metal by using the device. The device is simple in structure, free of gravity field limitation, convenient to sample and high in impurity removal efficiency.

Description

Technical Field

[0001] The 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 electronic instruments, aerospace, modern communications, photovoltaic semiconductors, etc., the demand for high-purity metals is growing. High-purity metals play a vital role in these fields due to their excellent physical and chemical properties. For example, high-purity tellurium is widely used in special alloys, high-end special steels, semiconductors and battery materials due to its excellent thermoelectric properties, optical properties, physical properties, heat transfer properties, etc., which significantly improves the performance and quality of these materials.

[0003] To date, the main methods for preparing high-purity metals include electrolysis, zone melting and vacuum distillation. The metals produced by electrolysis are generally not of high purity; the zone melting method has low production efficiency; 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 currently 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, the process of preparing high-purity metals by vacuum distillation still faces 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 mainly depends on the difference in saturated vapor pressure of substances, which directly affects the purification effect and efficiency. It can be said that saturated vapor pressure is the key factor affecting the purification effect and efficiency of vacuum distillation. Taking tellurium as an example, the saturated vapor pressure of tellurium and impurity metals is calculated to judge 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 calculation results are shown in Table 1 below.

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

[0006]

[0007]

[0008] When the temperature is 550℃~650℃, the saturated vapor pressure of tellurium and some impurity elements is quite different. At this time, tellurium and impurities are easier to separate during vacuum distillation. Therefore, the experimental and production processes are generally controlled at 550℃~650℃. As shown in Table 1, in the temperature range of 550℃~650℃, the saturated vapor pressure of impurities such as Na, Mg, Se, and As is similar to that of tellurium, and it is difficult to remove them by traditional vacuum distillation equipment and methods.

[0009] CN117821762A discloses a coupling device and production method for preparing high-purity metals by vacuum distillation and zone melting, which can prepare 6N high-purity metals using 2N raw materials. However, the device is equipped with multiple complex precision components and control systems, with high manufacturing costs and difficult maintenance; the coupling of vacuum distillation and zone melting technology will cause problems such as high energy consumption.

[0010] CN117298634A discloses a vacuum distillation device for preparing high-purity metals by vacuum gradient condensation, which uses 2N-3N raw materials to prepare 4N-5N high-purity metals. The device belongs to a vertical distillation furnace, and has the following problems: impurity migration is easily affected by the gravity field during the vacuum distillation of high-purity metals, the impurity removal efficiency is not stable, and the gradient condensation is not obvious. At the same time, due to the characteristics of some high-purity metals, the device has the disadvantages of 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 metal by vacuum distillation bidirectional step condensation with simple structure, no gravity field limitation, 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 by utilizing the device for preparing high-purity metal by vacuum distillation bidirectional step condensation.

[0013] The technical solution adopted by the present invention to solve its technical problems is: a device for preparing high-purity metal by vacuum distillation bidirectional step condensation, comprising an atmosphere control device, a vacuum distillation device and its control device, and a charging device, wherein the atmosphere control device comprises a nitrogen bottle and a control valve 1 arranged above the bottle mouth for controlling the opening and closing of the nitrogen bottle, the vacuum distillation device comprises a shell, a vacuum distiller installed in the shell, and a vacuum pump arranged outside the shell and connected to the vacuum distillation device through a pipeline, the charging device is arranged in the middle of the vacuum distillation device, and 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, and condensation zone 1 and condensation zone 2 are respectively connected by connecting valves between condensation zone 1 and distillation zone and between condensation zone 2 and distillation zone. The connecting channel 1 is connected with 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 arranged 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 arranged at the 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 tail gas treatment device includes an impurity removal device, in which filter cotton and tail gas treatment liquid are installed, which is used to collect metal particles and impurity gases volatilized from the vacuum distillation device, which is helpful to obtain high-purity metal.

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

[0016] Further, 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 50-70mm, 370-500mm, and 80-100mm from right to left, respectively, and the heights of each step from bottom to top are 0mm, 5-10mm, and 10-20mm, respectively; the lengths of the distillation graphite boat one and the distillation graphite boat two are 500-670mm; the lengths of the three stepped platforms of the three-step condensation graphite boat two are 50-70mm, 370-500mm, and 80-100mm from left to right, respectively, and the heights of each step from bottom to top are 0mm, 5-10mm, and 10-20mm, respectively; the widths of each stepped platform 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.

[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, and also to 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 grade; 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 metals.

[0023] Furthermore, in a preferred embodiment of the device of the present invention, four heaters are respectively set in the two condensation zones, and four heaters are set in the distillation zone. Each heater and the connection port of the connecting channel between the distillation zone and the condensation zone are electrically connected to the intelligent control device respectively. Each heater can realize independent control of 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. The reasonable operation of the vacuum distillation device is realized by sharing some equipment and components. The distillation operation is located in the distillation zone, and the raw material is evaporated by providing heat through the heater. The steam of the raw material enters the condensation zone through the connection port of the connecting channel and condenses in the condensation zone. During the distillation process, a partition is provided between the first distillation graphite boat and the second distillation graphite boat to avoid cross contamination between the raw materials.

[0024] Furthermore, another embodiment of the device of the present invention is to set 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 arranged 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 technical solution adopted by the present invention to further solve the technical problem 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 device;

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

[0028] (S3) according to the saturated vapor pressure of the raw materials, the distillation temperature and distillation time of the distillation zone and the condensation temperature and condensation 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, and the first step condensation graphite boat and the second step condensation graphite boat. After the distillation and condensation of the distillation zone, the condensation zone 1 and the condensation zone 2 are completed respectively, 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 products in the middle-stage platform part of the staged condensed graphite boat are 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 adjusted to 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 relatively high temperature is set so that impurities with similar saturated vapor pressures 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 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 material loaded in step S1 is determined according to the volume of the distillation graphite boat.

[0037] Since some impurity metals in high-purity metals have a saturated vapor pressure similar to that of the base metal, it is difficult to effectively separate such impurity metals from the base metal during the distillation process. Therefore, a relatively high temperature is first set during the distillation and condensation process, so that the impurities with similar saturated vapor pressures are first volatilized to the outermost graphite boat platform of the stepped condensation graphite boat; after maintaining for a period of time, the distillation and condensation temperatures are appropriately lowered, so that the base metal is uniformly condensed in the middle of the stepped condensation graphite boat; after all raw materials are distilled, the condensation zone is continuously heated at the original condensation temperature, so that the impurities with higher volatilization temperatures and more difficult to volatilize are volatilized 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 in the stepped platforms on both sides have a lower purity.

[0038] Since the raw materials contain more main metal and less 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 treatment 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 device for preparing high-purity metal by vacuum distillation bidirectional step condensation of the present invention is a device for preparing high-purity metal by bidirectional step condensation, which can effectively realize step condensation impurity removal, clarify the impurity migration mechanism, realize vacuum distillation of two batches of raw materials in the same device at the same time, and has high production efficiency. It is suitable for the preparation of various 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 metals, thereby improving the purity of the obtained metal products; (2) Setting up independent temperature-controlled heaters: The condensation zone and the distillation zone in the device are respectively provided with a plurality of heaters, each of which can achieve independent temperature control; this design enables the distillation and condensation processes to be more accurately controlled, thereby improving the production efficiency and quality of high-purity metals; (3) Application of intelligent control devices: Through the intelligent control device, the switch of each heater and the heating and cooling speed and amplitude can be controlled separately, and the opening and closing of each connection port can be controlled separately, thereby improving the degree of automation of the operation, reducing the error of manual operation, and helping to improve production efficiency and safety; (4) The filter cotton and the 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, thereby helping to obtain high-purity metals. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0043] Figure 2 It is a 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 bottle; 2. control valve one; 3. vacuum distillation device; 31. condensation zone one; 32. distillation zone one; 33. condensation zone two; 311. heater one; 312. first-stage condensation graphite boat; 321. heater two; 322. partition; 323. first distillation graphite boat; 324. second distillation graphite boat; 331. heater three; 332. second-stage condensation graphite boat; 34. connecting channel one, 341. connecting port one; 342. connecting pipe one; 35. connecting channel two, 351. connecting pipe two; 352. connecting port two; 4. intelligent control device; 5. vacuum pump; 6. control valve two; 7. exhaust gas treatment device. DETAILED DESCRIPTION

[0046] The specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings and embodiments. These embodiments shall 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 embodiments of the present invention are purchased from the market or prepared by known existing methods.

[0048] Example 1

[0049] Reference Figure 1 , 2The device for preparing high-purity metal by vacuum distillation bidirectional step condensation in this embodiment comprises an atmosphere control device, a vacuum distillation device 3 and its control device, and a charging device. The atmosphere control device comprises a nitrogen bottle 1 and a control valve 2 arranged 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 arranged outside the shell and connected to the vacuum distillation device 3 through a pipeline. The charging device is arranged in the middle of the vacuum distillation device 3. The vacuum distillation device 3 is laterally divided into a condensation zone 1 31, a distillation zone 32 and a condensation zone 2 33 in sequence by a partition. The condensation zone 1 31 and the condensation zone 2 33 are located on both sides of the distillation zone 32. The condensation zone 1 31 and the distillation zone 32 are connected as well as the condensation zone 2 33 and the distillation zone 32 through a connecting channel 1 34 and a connecting channel 2 35 respectively. The connecting channel 1 34 is connected by a connecting pipe 341 and a connecting pipe 341 arranged at the connecting pipe 341. 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 tube 2 351 and a connecting port 2 352 that can be switched on and off at the end of the connecting tube 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 in parallel 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 plate 322 is provided between the first distillation graphite boat 323 and the second distillation graphite boat 324 .

[0051] The tail gas treatment device 7 includes an impurity removal device; the impurity removal device is equipped with filter cotton and tail gas treatment liquid; it is used to collect metal particles and impurity gases volatilized from the vacuum distillation device, which is helpful 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, the length of each heater is 150 mm, the lateral parallel spacing of each heater in the condensation zone 1, the distillation zone and the condensation zone 2 is 10 mm, and the lateral parallel spacing between the condensation zone 1, the distillation zone and the condensation zone 2 is 15 mm.

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

[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, and 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 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.

[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 heating and cooling, and 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 metallic tellurium using the apparatus for preparing high-purity metal by vacuum distillation 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 device 3;

[0060] (S2) Open the connection port 1 341 and the connection port 2 352, 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 is below; close the connection port 1 341 and the connection port 2 352;

[0061] (S3) starting the intelligent control device 4, turning on the heater 1 311, the heater 2 321, and the heater 3 331 through the intelligent control device 4, starting heating and distillation, and after the distillation and condensation of 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;

[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 in the first three-step condensation graphite boat 312 of the condensation zone 1 and the second three-step condensation graphite boat 332 of the condensation zone 2 respectively; retaining the products in the middle step platform part of the three-step condensation graphite boat;

[0064] (S6) Using the products in the step 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, repeating steps S1 to S5 to achieve continuous production of high-purity tellurium.

[0065] In this embodiment, in step S1, the tellurium material loading amount is 1000g; when nitrogen is introduced, the nitrogen flow rate is regulated to be 1L / min, and the ventilation time is 30min; the distillation temperature of the distillation zone 42 is first set to 450°C, maintained for 180min, and then set to 525°C, maintained for 270min, 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 180min, and then set to 200°C, maintained for 270min.

[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 length of the first distillation graphite boat 423 and the second distillation graphite boat 424 .

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

[0068] Table 2 Statistical table 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] Embodiment 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 device 3;

[0073] (S2) Open the connection port 1 341 and the connection port 2 352, 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 is below; close the connection port 1 341 and the connection port 2 352;

[0074] (S3) turning on the heater 321 to start heating distillation, and after the distillation and condensation of 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 restoring 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, repeat steps S1 to S5 to achieve continuous production of high-purity selenium.

[0078] In this embodiment, in the step S1, the amount of selenium material loaded is 1000g; in the step S2, when nitrogen is introduced, the nitrogen flow rate is regulated to 1L / min, and the ventilation time is 30min; in the step S3, the distillation temperature of the distillation zone 42 is first set to 220°C, maintained for 90min, and then set to 450°C, maintained for 240min, 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 90min, and then set to 100°C, maintained for 240min.

[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 tested by ICP-MS. 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 Statistical table 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] Embodiment 4:

[0084] This embodiment uses the device 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 device 3;

[0086] (S2) Open the connection port 1 341 and the connection port 2 352, 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 is below; close the connection port 1 341 and the connection port 2 352;

[0087] (S3) turning on the heater 321 to start heating distillation, and after the distillation and condensation of 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 restoring to normal pressure;

[0089] (S5) taking out the products in the step-condensation graphite boat 1 312 and the step-condensation graphite boat 2 332 respectively; the products in the middle part of the step-condensation graphite boat are 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 loading amount of the indium material is 1000g; in the step S2, when the nitrogen is introduced, the nitrogen flow rate is adjusted to 1L / min, and the ventilation time is 30min; in the step S3, the distillation temperature of the distillation zone 42 is first set to 200°C, the distillation time is 80min, and then set to 1000°C, and maintained for 240min, and the condensation temperature of the step condensation zone 1 31 and the step condensation zone 2 33 is first set to 850°C, maintained for 80min, and then set to 700°C, and maintained for 240min.

[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 Statistical table 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 The apparatus described in the invention firstly loads the tellurium material into the horizontal vacuum distillation furnace, then starts the vacuum pump to evacuate the horizontal vacuum distillation furnace, and finally starts the heating program. The distillation temperature of the distillation zone is first set to 450°C, maintained for 180 minutes, then set to 525°C, maintained for 270 minutes, and the temperature of the condensation zone is first set to 400°C, maintained for 180 minutes, then set to 200°C, maintained for 270 minutes. The results of the impurity content analysis of the distillation product by ICP-MS are 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: Figure 3 The device described in the invention firstly loads the selenium material into the horizontal vacuum distillation furnace, then starts the vacuum pump to evacuate the horizontal vacuum distillation furnace, and finally starts the heating program. The distillation temperature of the distillation zone is first set to 220°C, maintained for 90 minutes, then set to 450°C, maintained for 240 minutes, and the temperature of the condensation zone is first set to 200°C, maintained for 90 minutes, then set to 100°C, maintained for 240 minutes. The results of the impurity content analysis of the distillation product by ICP-MS are shown in Table 6.

[0102] Table 6 Statistical table 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 The device described in the invention firstly loads the indium material into the horizontal vacuum distillation furnace, then starts the vacuum pump to evacuate the horizontal vacuum distillation furnace, and finally starts the heating program. The distillation temperature of the distillation zone is first set to 200°C, the distillation time is 80min, then set to 1000°C, and maintained for 240min. The temperature of the condensation zone is first set to 850°C, maintained for 80min, then set to 700°C, and maintained for 240min. The results of the impurity content analysis of the distillation product by ICP-MS are shown in Table 7.

[0106] Table 7 Statistical table 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 contents of impurity elements meet the industry standards for high-purity metals. The purification device provided by the present invention can be used to prepare high-purity metals.

[0109] Although the above embodiment describes the present invention in detail, 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 protection scope of the present invention.

Claims

1. A device for preparing high-purity metal by vacuum distillation and bidirectional step condensation, comprising an atmosphere control device, a vacuum distillation device (3) and its 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 housing, a vacuum distiller installed in the housing, and a vacuum pump (5) disposed outside the housing and connected to the vacuum distillation device (3) through a pipeline; the charging device is disposed in the vacuum distillation device The vacuum distillation device (3) is in the middle of the vacuum distillation device (3), and the interior of the vacuum distillation device (3) is divided into a condensation zone 1 (31), a distillation zone (32) and a condensation zone 2 (33) in sequence by a partition plate in the horizontal direction. The condensation zone 1 (31) and the condensation zone 2 (33) are located on both sides of the distillation zone (32). The condensation zone 1 (31) and the distillation zone (32) are connected by a connecting channel 1 (34) and a connecting channel 2 (35) respectively. The connecting channel 1 (34) is connected by a connecting pipe (341) and a connecting pipe (342) provided on the connecting pipe (343). 41) is composed of a connecting port 1 (342) that can be opened and closed at the end of the connecting pipe (351); the connecting channel 2 (35) is composed of a connecting pipe 2 (351) and a connecting port 2 (352) that can be opened and closed 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 step condensation graphite boat (312) and a second step condensation graphite boat (332); the condensation zone A plurality of heaters (311, 321, 331) are provided on both sides of the first (31), distillation zone (32) and condensation zone second (33), and the plurality of heaters are arranged in parallel along the length direction of the charging device and the distillation zone (32), condensation zone one (31) and condensation zone two (33); an exhaust gas treatment device (7) is also provided outside the shell of the vacuum distillation device (3); and 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).

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

3. The device for preparing high-purity metal by vacuum distillation bidirectional step condensation according to claim 1 or 2, characterized in that: The first-stage condensed graphite boat (312) and the second-stage condensed graphite boat (332) are both three-stage condensed graphite boats.

4. The device for preparing high-purity metal by vacuum distillation bidirectional step 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 impurity removal device (7) is equipped with filter cotton and tail gas treatment liquid.

5. The device for preparing high-purity metal by vacuum distillation bidirectional step condensation according to claim 4, characterized in that: The lengths of the three stepped platforms of the first to third step 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 second 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 to third step 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 boats and the width of the distillation graphite boats are adapted to the inner wall of the shell of the vacuum distillation device (3).

6. The device for preparing high-purity metal by vacuum distillation bidirectional step condensation according to any one of claims 1 to 5, characterized in that: 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).

7. The device for preparing high-purity metal by vacuum distillation bidirectional step condensation according to any one of claims 1 to 6, characterized in that: 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).

8. A method for preparing high-purity metal by vacuum distillation bidirectional step condensation using the device according to any one of claims 1 to 7, 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) Opening the connection port 1 (341) and the connection port 2 (352) through the intelligent control device 4, introducing nitrogen into the vacuum distillation device (3) to remove air impurities in the device; closing the control valve 1 (2) and the control valve 2 (6); using the vacuum pump (5) to reduce the vacuum degree in the vacuum distillation device (3) to 10 -4 Pa or less; 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 step condensation zone 1 (31) and the step 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 step condensation graphite boat (312) and the second step 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 part 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, and realizing continuous production of high-purity metal.

9. The method for preparing high-purity metal by vacuum distillation bidirectional step condensation according to claim 8, characterized in that: When nitrogen is introduced, the nitrogen flow rate is adjusted to 0.8-1.2 L / min and the ventilation time is 30 min-60 min.

10. The method for preparing high-purity metal by vacuum distillation bidirectional step condensation according to claim 8 or 9, 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 distillation graphite boat 1 (323) and the distillation graphite boat 2 (324); During the condensation process, a relatively high temperature is first set so that impurities with similar saturated vapor pressures evaporate to the outermost graphite boat platform of the stepped condensation graphite boat; after maintaining this temperature 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 matrix metal.

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