Repeated continuous vacuum sublimation purification device and method

Abstract

The invention discloses a multi-continuous vacuum sublimation purification device and method. The device comprises a tubular furnace body and a vacuum extraction system, the periphery of the furnace body is sleeved with a heating device; a detachable baffle and a condensation base plate are arranged in the furnace body in the axial direction front and back, a closed sublimation purification section is formed in the furnace body, and the condensation base plate is made of a high-purity material; when the heating device slowly moves towards the baffle, the to-be-purified material at one end of the baffle can be sublimated and condensed at one end of the condensation base plate; and if n times of vacuum sublimation purification are needed, the length of the furnace body is not less than the length of the constructed n sublimation purification sections. According to the invention, through the axial movement of the baffle plate in the furnace body and the addition of a new condensation substrate, a new sublimation purification section is continuously constructed, and a new sublimation purification section is formed after each purification. According to the vacuum sublimation purification device, repeated and continuous vacuum sublimation purification of materials is realized on the premise that discharging and charging do not need to be carried out again.

Description

Technical Field

[0001] The invention belongs to the technical field of vacuum sublimation of single substances / compounds, and in particular relates to a multiple continuous vacuum sublimation purification device and method. Background Art

[0002] High-purity elements and compounds have been widely used in electronic information, optoelectronics, photovoltaics, 5G communications and other fields, which usually have extremely high requirements for the purity of elements and compounds. For example, high-purity arsenic can be used to synthesize compounds such as gallium arsenide, indium arsenide, and arsenic selenide to prepare diodes, cathode ray tubes, microwave ovens, and solar cells; high-purity cadmium telluride is the core key material for preparing cadmium telluride solar thin-film batteries, and its purity is usually required to be above 5N. At present, vacuum sublimation is the main method for preparing high-purity elements and compounds, which can effectively remove high and low vapor pressure impurities in elements and compounds. The vacuum sublimation technology in the prior art has limited efficiency in one-time purification, and multiple purifications require re-extraction and reloading of the furnace, which is inconvenient to operate. After multiple sublimation purifications, the residual material will increase, and it may also lead to an increase in high vapor pressure impurities.

[0003] Prior art CN202210188924.3 discloses a vacuum sublimation purification device, comprising: a weight sensor, a fixing, a sealing member, a controller, a heating wire and a vacuum sublimation tube; sealing members are respectively provided at both ends of the vacuum sublimation tube; the sealing member is provided with an opening, and a part of the fixing member extends into the vacuum sublimation tube through the opening, and the connection between the fixing member and the opening is sealed so as not to destroy the airtightness of the vacuum sublimation tube; the weight sensor is arranged at the part of the fixing member extending into the vacuum sublimation tube, and is connected to the controller; a heating wire connected to the controller is provided on the outer wall of the vacuum sublimation tube, and different heating wires are provided in different temperature zones; the controller is used to obtain the diffusion rate of the raw material according to the weight information returned by the weight sensor, and control the temperature of each heating wire according to the diffusion rate. In addition, patents CN210856291U, CN211158660U, CN114558343B, and CN101225479A announced solutions for vacuum sublimation purification technology, which mainly develop and transform the furnace structure, condensation device, and temperature control system.

[0004] In order to obtain materials with higher purity, it is often necessary to undergo multiple vacuum sublimation purifications. In the above prior art, each purification requires re-discharging and refilling of materials, making the entire purification process more cumbersome. In addition, other impurities are easily introduced during the refilling process, further affecting the purity of the material. Summary of the invention

[0005] In view of this, the present invention provides a multiple continuous vacuum sublimation purification device and method, which can purify materials multiple times continuously without re-discharging and refilling materials. In order to solve the above technical problems, the technical solution of the present invention is to adopt a multiple continuous vacuum sublimation purification device, including a tubular furnace body and a vacuum extraction system connected to the furnace body for extracting vacuum for the furnace body; a heating device is arranged on the outer periphery of the furnace body; the furnace body and the heating device can move axially relative to each other; a detachable baffle and a condensation substrate are arranged in the axial front and rear of the furnace body to form a closed sublimation purification section in the furnace body, and the condensation substrate is made of high-purity material; the heating device is located between the baffle and the condensation substrate, and the axial distance between the heating device and the material to be purified is initially threshold distance, and when the heating device moves toward the baffle, the material to be purified at one end of the baffle can be sublimated and condensed at one end of the condensation substrate; when the material in the sublimation purification section is sublimated and condensed, the baffle can be moved toward one end of the condensation substrate in the furnace body, and another condensation substrate can be installed to form a new sublimation purification section, and the condensed material is located at one end of the baffle; the relative position of the heating device and the furnace body is changed, so that the axial spacing between the heating device and the condensed material is the threshold distance; if n vacuum sublimation purifications are required, the length of the furnace body shall not be less than the length of constructing n sublimation purification sections.

[0006] As an improvement, it also includes a displacement control system for driving the axial movement of the furnace body; the displacement control system includes a transmission rod arranged parallel to the furnace body, and the furnace body is connected to the transmission rod by a connecting frame, so that the furnace body can move axially along the transmission rod. As a further improvement, it also includes a displacement control system for driving the axial movement of the heating device; the displacement control system includes a transmission rod arranged parallel to the furnace body, and the heating device is connected to the transmission rod by a connecting frame, so that the heating device can move axially along the transmission rod. As another further improvement, the transmission rod is a lead screw, and the connecting frame is threadedly matched with the lead screw; the transmission rod is driven to rotate by a servo motor.

[0007] As an improvement, the furnace body is made of quartz, the baffle is made of graphite, and the condensation substrate is made of high-purity material.

[0008] As an improvement, the length of the heating device is not less than 1.2 times the length of the material to be purified.

[0009] As an improvement, the vacuum extraction system includes a vacuum pump, and the vacuum pump is connected to two ends of the furnace body by a vacuum pipe; a vacuum gauge and a vacuum valve are provided on the vacuum pipe.

[0010] As an improvement, the heating device is a resistance wire.

[0011] The present invention also provides a multiple continuous vacuum sublimation purification method, which is applied to the multiple continuous vacuum sublimation purification device, comprising: S1: Fill the material to be purified at the end of the baffle in the sublimation purification section of the furnace body, and make the axial distance between the heating device and the material to be purified be a threshold distance; S2 draws vacuum on the furnace body; S3: heating the sublimation purification section of the furnace to a first threshold temperature range by means of a heating device, and heating the temperature for a first threshold time; S4 drives the heating device to move toward the baffle end, so that the material to be heated sublimates during the movement and condenses at one end of the condensation substrate; S5: After the material to be purified is completely sublimated and re-condensed, the condensed material is cooled; S6: moving the baffle plate toward one end of the condensation substrate in the furnace body, and installing another condensation substrate to form a new sublimation purification section, so that the condensed material is located at one end of the baffle plate, and at the same time, the axial distance between the heating device and the material to be purified is maintained at the threshold distance again; S7 repeats steps S2 to S6 until the purification times are completed.

[0012] As an improvement, during vacuum sublimation purification, the relative movement speed of the heating device and the furnace body is 70-100 mm / h; The time for one purification is calculated using the formula t=kl / v, where t is time, k is the correction coefficient, l is the length of the material, and v is the relative movement speed of the heating device and the furnace body.

[0013] The present invention is beneficial in that: The existing vacuum sublimation purification technology can purify elements and compounds such as arsenic and cadmium telluride, but the impurity removal efficiency of a single purification is low. Although multiple sublimations can improve the impurity removal efficiency, the operation is complicated, the residual material will increase (the yield will decrease), and high vapor pressure impurities may be enriched in the product.

[0014] The present invention continuously constructs a new sublimation purification section by axially moving the baffle in the furnace body and adding a new condensation substrate. Each additional purification must form a new sublimation purification section. The present invention realizes multiple and continuous vacuum sublimation purification of materials without the need for re-discharging and reloading, so that impurities in simple substances and compounds remain on the furnace wall of the sublimated material or are enriched at the end (left end) of the purified material, and the purified simple substance or compound is obtained by cutting off the end. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the initial state in Example 1 of the present invention.

[0016] Figure 2 This is a schematic diagram of a portion of the material after sublimation and condensation in Example 1 of the present invention.

[0017] Figure 3This is a schematic diagram after one purification is completed in Example 1 of the present invention.

[0018] Markings in the figure: 1a is a heating device, 1b is a material to be purified, 1c is a baffle, 1d is a condensation substrate, 1e is a furnace body, and 1f is the condensed material; 2a is a vacuum gauge, 2b is a vacuum valve, and 2c is a vacuum pump; 3a is a servo motor, 3b is a transmission rod, and 3c is a connecting frame. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific implementation methods.

[0020] Example 1 In order to achieve multiple continuous vacuum sublimation purification of materials, such as Figure 1 As shown, the present invention provides a multiple continuous vacuum sublimation purification device, comprising a tubular furnace body 1e and a vacuum extraction system connected to the furnace body 1e for extracting vacuum for the furnace body 1e; a heating device 1a is provided on the outer periphery of the furnace body 1e; the furnace body 1e and the heating device 1a can move relative to each other in the axial direction; a detachable baffle 1c and a condensation substrate 1d are arranged in the furnace body 1e along the axial direction to form a closed sublimation purification section in the furnace body 1e, and the condensation substrate 1d is made of high-purity material; the heating device 1a is located between the baffle 1c and the condensation substrate 1d, and the axial distance between the heating device 1a and the material to be purified 1b (i.e. Figure 1 The distance between the left end face of the heating device 1a and the right end face of the material 1b to be purified is initially a threshold distance (generally 1-2 cm), and when the heating device 1a moves toward the baffle 1c, the material 1b to be purified at one end of the baffle 1c can be sublimated and condensed at one end of the condensation substrate 1d; when the material in the sublimation and purification section is sublimated and condensed, the baffle 1c can be moved in the furnace body 1e to one end of the condensation substrate 1d, and another condensation substrate 1d can be installed to form a new sublimation and purification section, and the condensed material 1f is located at one end of the baffle 1c; the relative position of the heating device 1a and the furnace body 1e is changed, so that the left end face of the heating device 1a and the right end face of the material 1f after the last sublimation and purification maintain the threshold distance again.

[0021] Since each purification requires the construction of a new sublimation purification section, it can be understood that if n vacuum sublimation purifications are required, the length of the furnace body should not be less than the length of constructing n sublimation purification sections.

[0022] In fact, there will be a partial overlap between two adjacent sublimation purification sections, that is, the length of the condensed material 1f. Therefore, the length of the furnace body 1e at least reserves the length of two heating devices 1a, so as to achieve at least two consecutive purifications.

[0023] Of course, the reserved length of the furnace body 1e can be determined according to the number of purification times. For example, if continuous purification is required for three times, the reserved length of the furnace body 1e cannot be less than three times of the heating device 1a; if continuous purification is required for five times, the reserved length of the furnace body 1e cannot be less than five times of the heating device 1a, and so on.

[0024] The "high purity material" used to make the condensation substrate 1d in the present invention refers to a material whose purity is not lower than the target purity of the material to be purified 1b. For example, if 4N cadmium telluride needs to be purified to 5N, the purity of the cadmium telluride used to make the condensation substrate 1d cannot be lower than 5N.

[0025] The actual relative distance between the newly added condensation substrate 1d and the moved baffle 1c is the sum of the length of the last sublimation purification section and the thickness of the condensation substrate 1d, thereby ensuring that the relative positions of the heating device, the right end face of the material to be purified, and the condensation substrate remain unchanged during multiple purification processes.

[0026] In the present invention, the material 1b to be purified is sublimated from one end of the baffle 1c in the sublimation purification section and condensed at one end of the condensation substrate 1d to achieve one purification. After one purification is completed, a new sublimation purification section is formed in the furnace body 1e by moving the baffle 1c and adding a condensation substrate 1d to perform the next purification. Theoretically, as long as the furnace body 1e is long enough, unlimited continuous purification can be achieved, and each purification does not require refilling of the condensed material 1f, but only relies on moving the baffle 1c and adding a condensation substrate 1d. Compared with the existing vacuum sublimation purification, it is more efficient and has a lower risk of introducing other impurities.

[0027] Specifically, the furnace body 1e and the heating device 1a of the present invention can move axially relative to each other, that is, the furnace body 1e can be fixed and the heating device 1a can move axially, or the heating device 1a can be fixed and the furnace body 1e can move axially, or even both of them can move axially.

[0028] Therefore, in this embodiment, when the heating device 1a is fixed and the furnace body 1e moves axially, it also includes a displacement control system for driving the furnace body 1e to move axially; the displacement control system includes a transmission rod 3b arranged parallel to the furnace body 1e, and the furnace body 1e is connected to the transmission rod 3b by a connecting frame 3c, so that the furnace body 1e can move axially along the transmission rod 3b.

[0029] When the furnace body 1e is fixed and the heating device 1a moves axially, it also includes a displacement control system for driving the heating device 1a to move axially; the displacement control system includes a transmission rod 3b arranged parallel to the furnace body 1e, and the heating device 1a is connected to the transmission rod 3b by a connecting frame 3c, so that the heating device 1a can move axially along the transmission rod 3b.

[0030] More specifically, the transmission rod 3b is a lead screw, and the connecting frame 3c is threadedly matched with the lead screw; the transmission rod 3b is driven to rotate by the servo motor 3a. The rotation of the transmission rod 3b causes the connecting frame 3c and the furnace body 1e or the heating device 1a fixed to the connecting frame 3c to move axially.

[0031] It is understandable that there are many mechanisms that can drive the furnace body 1e or the heating device 1a to move axially, as long as the purpose of the invention can be achieved, and the present invention does not limit the specific structure of the displacement control system.

[0032] In this embodiment, the furnace body 1e is made of high-purity quartz tube; the baffle 1c is made of high-purity graphite to prevent the material from being contaminated.

[0033] In addition, in order to allow the material 1b to be purified to condense on the condensation substrate 1d, it is foreseeable that the heating device 1a will not cover the entire sublimation purification section, but will reserve a sufficient length so that the sublimated material vapor can be cooled and condensed. In addition, the area where the material in the furnace body 1e forms vapor after sublimation is the vaporization space area, and the length of the heating device 1a can determine the length of the vaporization space (the two are proportional), and the vaporization space contains a large amount of high vapor pressure impurities. In order to ensure the purification effect, generally speaking, the length of the heating device 1a should not be less than 1.2 times the length of the material 1b to be purified.

[0034] In this embodiment, the heating device 1a is a resistance wire arranged around the outer periphery of the furnace body 1e, and the temperature inside the furnace body can be conveniently adjusted by energizing in groups or increasing or decreasing the power. Of course, the heating device 1a can also be in other forms, which is also not limited in the present invention.

[0035] The vacuum extraction system in this embodiment includes a vacuum pump 2c, which is connected to both ends of the furnace body 1e by a vacuum pipe; a vacuum gauge 2a and a vacuum valve 2b are provided on the vacuum pipe. The vacuum pump 2c is used to extract vacuum from the furnace body 1e, thereby providing dynamic conditions for the volatilization of the material and preventing the material from reacting with the gas in the air at high temperature.

[0036] Figure 1~Figure 3 The whole process of purification is demonstrated.

[0037] Figure 1In the figure, the furnace body 1e area covered by the heating device 1a is roughly the gasification space area, the left end of the gasification space is the material to be purified 1b, and the right end of the gasification space is the condensation substrate 1d that provides suitable condensation conditions. The specific position is in the gasification space 2 to 3 cm away from the right line of the gasification space, so that the temperature of the condensation substrate 1d is slightly lower than the condensation (desublimation) temperature of the gaseous material. When the furnace body 1e moves, the servo motor 3a can drive the furnace body 1e to move slowly from left to right through the transmission rod 3b and the connecting frame 3c. At this time, the material to be purified 1b at the left end enters the gasification space and begins to sublimate, and then the gaseous material is transmitted from the left end to the right end of the gasification space, and the condensation substrate 1d at the right end will begin to gradually leave the heating zone, so that the gaseous material will slowly condense on the condensation substrate 1d after reaching the condensation conditions, that is, the gasification space moves from right to left relative to the furnace body 1e.

[0038] Figure 2 In the process, the gasification space is between the material to be purified 1b and the condensed material 1f. The material on the left side of the gasification space is almost completely volatilized, and the low vapor pressure impurities will remain on the wall of the furnace body 1e at the location together with a very small part of the material. Then the gaseous material will condense at the right side of the gasification space. During the condensation process, high vapor pressure impurities are volatile and tend to be enriched in the gas phase. They are not easy to condense relative to the purified material, resulting in a relatively low concentration of high vapor pressure impurities in the condensed material, which is much lower than the impurity concentration in the gas phase. At this time, there is a significant difference in the impurity concentration in the gas and solid phases, so this technology uses the difference in the concentration of impurities in the gas and solid phases for purification.

[0039] As the furnace body 1e moves slowly, the high vapor pressure impurities will also move to the left end of the furnace body 1e along with the gasification space, and finally condense at the left end of the purified material. Figure 3 Therefore, after one purification, the high vapor pressure impurities are enriched at the left end of the condensed material 1f, and the low vapor pressure impurities will remain on the wall of the furnace body 1e where the original material is located together with a very small part of the material.

[0040] After one purification is completed, the condensed material 1f remains in the furnace body without moving. When performing the second purification, it is only necessary to move the baffle 1c to the right and add a condensation substrate 1d at the corresponding spacing so that the condensed material 1f is located at the end of the baffle 1c. At this time, the furnace body 1e or the heating device 1a is moved so that the left end of the vaporization space formed by the heating device 1a on the furnace body 1e is relocated to the right side of the material to start the second purification.

[0041] Example 2 The present invention also provides a multiple continuous vacuum sublimation purification method, which is applied to the multiple continuous vacuum sublimation purification device. The present invention can be applied to the purification of single substances and compounds, with arsenic being an example of a single substance and cadmium telluride being an example of a compound, and the specific steps thereof include: S1: The material to be purified is densely packed at the end of the baffle in the sublimation purification section of the furnace body, and the axial distance between the heating device and the material to be purified is a threshold distance.

[0042] Before loading the material, pre-treatment can be performed: the furnace body is soaked in aqua regia and cleaned with ultrapure water; the baffle is cleaned with ultrapure water to remove graphite powder. Subsequently, the baffle is placed in the area covered by the heating device in the furnace body, vacuumed to below 20Pa, heated to 500-700℃, and baked for 2-4h to remove moisture and other impurities before use.

[0043] After the pretreatment is completed, the furnace body is densely filled with 5N arsenic or 4N cadmium telluride. The right end of the material to be purified is at a threshold distance (about 1 cm) from the left end of the heating device. The left end of the material to be purified is in complete and close contact with the baffle. The condensed substrate is at the right end of the vaporization space. Figure 1 shown.

[0044] S2 draws vacuum on the furnace body.

[0045] After the furnace is loaded and the furnace cover is closed, the vacuum pump is turned on and the vacuum is evacuated to below 20Pa.

[0046] S3: The sublimation purification section of the furnace is heated to a first threshold temperature range by a heating device and maintained for a first threshold time.

[0047] For arsenic, the temperature of the vaporization space is raised to 480-530° C. For cadmium telluride, the temperature of the vaporization space is raised to 750-800° C. After the temperature is raised to the first threshold temperature range, it is also necessary to maintain the first threshold time, such as 30 minutes.

[0048] S4 drives the heating device to move toward the baffle end, so that the material to be purified sublimates during the movement and condenses at one end of the condensation substrate.

[0049] After the temperature rises to the first threshold temperature range for 30 minutes, the furnace body (or heating device) is slowly moved from left to right by the servo motor through the transmission rod and the connecting frame, and the vaporization space moves from right to left relative to the furnace body. During the slow movement of the vaporization space, the vaporization space is controlled to be between the condensed material and the material to be purified. At the same time, in a vacuum environment of less than 20Pa, the material to be purified at the left end will slowly vaporize after entering the vaporization space. After the vaporized material migrates, it will continue to condense on the condensed material at the right end of the vaporization space. Figure 2 After the purified material has completely passed through the gasification space, the purification is completed. Figure 3As shown. The moving speed v of the quartz tube is controlled within the range of 70-100 mm / h. The purification time t can be determined according to the moving speed of the quartz tube and the length l of the material to be purified, which can be determined according to the empirical formula t=kl / v, where k is the correction coefficient, 0.95-1.1. The preferred time for one purification is controlled at 4-8h, and the length is about 40-60cm. Finally, one purification realizes the unidirectional condensation of the material along the axial direction.

[0050] S5 After the material to be purified is completely sublimated and re-condensed, the condensed material is cooled.

[0051] In this embodiment, air cooling can be used for cooling to improve cooling efficiency.

[0052] S6 moves the baffle toward one end of the condensation substrate in the furnace body, and installs another condensation substrate to form a new sublimation purification section, so that the condensed material is located at one end of the baffle, and at the same time, the axial distance between the heating device and the material to be purified is maintained at the threshold distance again.

[0053] After the material cools down after the last purification, close the vacuum valve and vacuum pump. Remove the cover on the left end of the furnace body, move the baffle so that the left end of the material is in complete and close contact with the graphite baffle, and move the gasification space (it can be a mobile furnace or a mobile heating device) so that it is at the right end of the material. Remove the cover on the right end of the furnace body, and place the new condensation substrate at the right end of the gasification space. The relative positions of the gasification space, baffle, and condensation substrate are the same as Figure 1 The relative positions of the three move to the right along the furnace body as a whole (the relative positions of the three move to the right along the furnace body as a whole).

[0054] S7 repeats steps S2 to S6 until the purification times are completed.

[0055] Repeat the operations in steps S2 to S6, the number of times 5N arsenic is purified to 7N is about 4-5 times, and the number of times 4N cadmium telluride is purified to 5N is about 2-3 times. Due to the migration of gaseous materials, multiple purifications can move the purified materials from the left end to the right end again and again. Therefore, in order to achieve multiple purifications, a certain length needs to be reserved at the right end of the furnace body, which is reserved according to the number of purifications (n). Therefore, the reserved length of the furnace body should not be less than nL, where L is the length of the heating device. Finally, multiple purifications can achieve unidirectional advancement of materials along the quartz tube.

[0056] S8 stops the furnace and discharges the materials.

[0057] After multiple purifications, close the vacuum valve and vacuum pump, wait for cooling, and take out the purified arsenic or cadmium telluride material. Since there are high vapor pressure impurities at the left end of the material, about 4-6% of the material at the left end needs to be removed, and the remaining material is 7N arsenic and 5N cadmium telluride. Low vapor pressure impurities will remain on the wall of the left end of the quartz tube that has passed through the heating device.

[0058] Example 1: For arsenic, the setting temperature of the heating area is 500℃, and the dynamic vacuum degree is 7-15Pa. The moving speed is 100mm / h, the purification times are 5 times, the moving time of one purification is 5.5h, the material length is 55cm, the length of the heating device is 70cm, and the material of about 3cm on the left end of the material is cut off. After purification, 5N arsenic can be purified to 7N.

[0059] The raw material is 5N arsenic, and the impurity content is as follows:

[0060] The purity of the purified arsenic is 7N, and the impurity content is as follows:

[0061] Example 2: For cadmium telluride, the setting temperature of the heating area is 760℃, and the dynamic vacuum is 6-11Pa. The moving speed is 95mm / h, the purification times are 2 times, the moving time of one purification is 5h, the material length is 50cm, the length of the heating device is 70cm, and the material of about 2.5cm on the left end of the material is cut off. After purification, 4N cadmium telluride can be purified to 5N. The raw material is 4N cadmium telluride, and the impurity content is as follows:

[0062] The purity of the purified cadmium telluride is 5N, and the impurity content is as follows: The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A multiple continuous vacuum sublimation purification device, characterized in that: The invention comprises a tubular furnace body and a vacuum extraction system connected to the furnace body for extracting vacuum for the furnace body; a heating device is provided on the outer periphery of the furnace body; the furnace body and the heating device can move relative to each other in the axial direction; a detachable baffle and a condensation substrate are arranged in the furnace body in the axial direction to form a closed sublimation purification section in the furnace body, and the condensation substrate is made of high-purity material; the heating device is located between the baffle and the condensation substrate, the axial spacing between the heating device and the material to be purified is a threshold distance at the beginning, and when the heating device moves toward the baffle, the material to be purified at one end of the baffle can be sublimated and condensed at one end of the condensation substrate; when the material in the sublimation purification section is sublimated and condensed, the baffle can be moved in the furnace body toward one end of the condensation substrate, and another condensation substrate can be added to form a new sublimation purification section, and the condensed material is located at one end of the baffle; the relative position of the heating device and the furnace body is changed so that the axial spacing between the heating device and the condensed material is a threshold distance; if n vacuum sublimation purifications are required, the length of the furnace body is not less than the length of constructing n sublimation purification sections.

2. A multiple continuous vacuum sublimation purification device according to claim 1, characterized in that: It also includes a displacement control system for driving the axial movement of the furnace body; the displacement control system includes a transmission rod arranged parallel to the furnace body, and the furnace body is connected to the transmission rod by a connecting frame, so that the furnace body can move axially along the transmission rod.

3. A multiple continuous vacuum sublimation purification device according to claim 1, characterized in that: It also includes a displacement control system for driving the heating device to move axially; the displacement control system includes a transmission rod arranged parallel to the furnace body, and the heating device is connected to the transmission rod by a connecting frame, so that the heating device can move axially along the transmission rod.

4. A multiple continuous vacuum sublimation purification device according to any one of claims 2 or 3, characterized in that: The transmission rod is a lead screw, and the connecting frame is threadedly matched with the lead screw; the transmission rod is driven to rotate by a servo motor.

5. A multiple continuous vacuum sublimation purification device according to claim 1, characterized in that: The furnace body is made of quartz, and the baffle is made of graphite.

6. A multiple continuous vacuum sublimation purification device according to claim 1, characterized in that: The length of the heating device is not less than 1.2 times the length of the material to be purified.

7. A multiple continuous vacuum sublimation purification device according to claim 1, characterized in that: The vacuum extraction system comprises a vacuum pump, and the vacuum pump is connected to two ends of the furnace body by means of a vacuum pipe; a vacuum gauge and a vacuum valve are arranged on the vacuum pipe.

8. A multiple continuous vacuum sublimation purification device according to claim 1, characterized in that: The heating method of the heating device is resistance heating.

9. A multiple continuous vacuum sublimation purification method, applied to the multiple continuous vacuum sublimation purification device according to any one of claims 1 to 8, characterized in that include: S1: Fill the material to be purified at the end of the baffle in the sublimation purification section of the furnace body, and make the axial distance between the heating device and the material to be purified be a threshold distance; S2 draws vacuum on the furnace body; S3: heating the sublimation purification section of the furnace to a first threshold temperature range by means of a heating device, and heating the temperature for a first threshold time; S4 drives the heating device to move toward the baffle end, so that the material to be heated sublimates during the movement and condenses at one end of the condensation substrate; S5: After the material to be purified is completely sublimated and re-condensed, the condensed material is cooled; S6: moving the baffle plate toward one end of the condensation substrate in the furnace body, and installing another condensation substrate to form a new sublimation purification section, so that the condensed material is located at one end of the baffle plate, and at the same time, the axial distance between the heating device and the material to be purified is maintained at the threshold distance again; S7 repeats steps S2 to S6 until the purification times are completed.

10. A multiple continuous vacuum sublimation purification method according to claim 9, characterized in that: During vacuum sublimation purification, the relative movement speed of the heating device and the furnace body is 70-100 mm / h; The time for one purification is calculated using the formula t=kl / v, where t is time, k is the correction coefficient, l is the length of the material, and v is the relative movement speed of the heating device and the furnace body.

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