A device and method for the production of radioactive iodine-131

Abstract

The application relates to the technical field of radioisotope preparation, and particularly discloses a preparation device and method for radioisotope iodine-131; the preparation device comprises a dry distillation furnace, the dry distillation furnace comprises a heating furnace and a furnace pipe; the heating furnace comprises a heating furnace body and a furnace cover, a furnace cavity is formed in the heating furnace body, an opening for realizing the communication between the furnace cavity and an external space is arranged on the heating furnace body, and the furnace cover is detachably connected with the heating furnace body to realize the sealing of the opening; the furnace pipe is arranged in the furnace cavity, and the furnace pipe comprises a containing pipe body and a furnace pipe cover; the containing pipe body is used for placing a boat, a taking and placing opening for taking and placing the boat is arranged on the containing pipe body, and the furnace pipe cover is detachably connected with the containing pipe body to realize the sealing of the taking and placing opening. The application not only can meet the needs of mass production, has high production efficiency, and has simple structure and easy operation, can reduce the equipment size, and effectively reduces the risk of leakage of the present radioactive gas.

Description

Technical Field

[0001] This invention relates to the field of radioactive isotope preparation technology, specifically to an apparatus and method for preparing radioactive iodine-131. Background Technology

[0002] The main methods for preparing iodine-131 are irradiation of uranium targets and irradiation of tellurium targets. Because irradiation of uranium-235 involves numerous side reactions, produces many impurities, has complex process conditions, and generates large amounts of high-level radioactive waste, only a few countries use this method. The tellurium irradiation method for preparing iodine-131 produces less waste, avoids contamination from alpha impurities and other fission products, yields high-purity products, and has low production costs, making it the method used by most countries.

[0003] The preparation of iodine-131 from tellurium targets using different extraction methods can be divided into two processes: wet and dry. The wet process uses tellurium powder as the target material, dissolving it with a large amount of acid and then distilling to obtain the product. This method has drawbacks such as generating a large amount of radioactive waste, making treatment difficult, cumbersome operation, and long processing time. The dry process uses TeO2 as the target material, obtaining the product through high-temperature dry distillation after irradiation. It has advantages such as high yield, high radioactive concentration and radiochemical purity, short production time, less radioactive waste, and high safety and reliability, and has become the primary method for iodine-131 preparation. However, the initial dry production process could only process tens of grams of target material per batch, requiring repeated loading and unloading of the equipment, complex operation, resulting in a large workload and high radiation dose for operators, and also had sealing problems, making it unsuitable for large-scale, rapid production.

[0004] To address the issue that existing dry processes have limited capacity and cannot meet the demands of large-scale, rapid production, patent (CN110694565B) describes a continuous-feed production apparatus for preparing radioactive iodine-131. By improving the feed boat and feeding method, it enables continuous feeding and continuous output of iodine-131 without shutting down the plant. This reduces the generation of solid waste during iodine-131 production, improves production efficiency, and reduces workload and radiation exposure.

[0005] However, the production device in CN110694565B has the following problems: 1) It has a complex structure, which not only requires processing into a large volume to complete the device, but also makes processing difficult; 2) The feeding method is controlled by multiple valves, which are prone to radioactive gas leakage, i.e., the airtightness control is difficult; 3) The operation is relatively complicated. Summary of the Invention

[0006] The purpose of this invention is to provide an apparatus and method for preparing radioactive iodine-131, which not only meets the needs of mass production and has high production efficiency, but also has a simple and easy-to-operate structure, can reduce equipment size, and effectively reduce the risk of radioactive gas leakage.

[0007] This invention is achieved through the following technical solution:

[0008] A device for preparing radioactive iodine-131 includes a dry distillation furnace, which includes a heating furnace and furnace tubes; the heating furnace includes a heating furnace body and a furnace cover, a furnace cavity is formed inside the heating furnace body, an opening is provided on the heating furnace body to enable communication between the furnace cavity and the external space, and the furnace cover is detachably connected to the heating furnace body to close the opening;

[0009] The furnace tube is placed inside the furnace cavity. The furnace tube includes a receiving tube body and a furnace tube cover. The receiving tube body is used to place the material boat. The receiving tube body is provided with a loading and unloading port for loading and unloading the material boat. The furnace tube cover is detachably connected to the receiving tube body to close the loading and unloading port.

[0010] The dry distillation furnace of the present invention is equipped with a thermocouple and a heating resistance wire. The heating resistance wire is used to heat the furnace cavity, and the thermocouple is used to detect the temperature. When the temperature reaches the set value, the heating is stopped. The thermocouple and heating resistance wire are existing technologies. Existing dry distillation furnaces also contain thermocouples and heating resistance wires. That is, existing dry distillation furnaces also use the same heating method to heat the furnace cavity to the required temperature.

[0011] The difference between the dry distillation furnace described in this invention and existing dry distillation furnaces is as follows:

[0012] The dry distillation furnace in patent CN110694565B is an integrated closed structure, including a closed heating furnace body. The T-shaped furnace tube does not have an opening for feeding and discharging. Instead, a hollow tube connected to the T-shaped furnace tube is set up, and a valve is set in the hollow tube to achieve continuous feeding.

[0013] The dry distillation furnace described in this invention does not employ a single, enclosed structure. Instead, it comprises a detachably connected heating furnace body and a furnace cover. By operating the furnace cover, the heating furnace body can be sealed, and the furnace cavity can be connected to the outer wall space. Feeding and unloading can be achieved through the openings on the heating furnace body.

[0014] Meanwhile, the furnace tube of the present invention does not adopt an integral closed structure. The furnace tube of the present invention includes a detachably connected receiving tube body and a furnace tube cover. By operating the furnace tube cover, the receiving tube body can be closed and the internal space of the receiving tube body can be connected with the furnace cavity. Material feeding and unloading can be achieved through the loading and unloading ports on the receiving tube body.

[0015] In addition, the feeding method of the present invention is different from that in patent CN110694565B. In patent CN110694565B, the feeding method is to directly fix the material boat inside the T-shaped furnace tube. The material boat has a special stepped structure. Material is continuously fed into the material boat through the hollow tube, and the material boat does not move.

[0016] In this application, the feeding is achieved by placing a boat containing the irradiated target material into the furnace tube. After the reaction is completed, the boat is directly removed from the furnace tube. That is, the present invention can achieve feeding and unloading by heating the opening on the furnace body and the loading and unloading port on the receiving tube body to load and unload the boat.

[0017] The original intention of this invention is:

[0018] The production apparatus for preparing radioactive iodine-131 disclosed in patent CN110694565B has the following problems: 1) It has a complex structure, which not only requires processing into a large volume to complete the apparatus, but also makes processing difficult; 2) The feeding method uses multiple valves for control, and the valves are prone to radioactive gas leakage, that is, the airtightness control is difficult; 3) The operation is relatively complicated.

[0019] The applicant found the device inconvenient and risky during use, therefore, it was necessary to upgrade and improve it. Through multiple designs and experiments, the inventors determined the structure of the preparation device described in this invention.

[0020] This invention features a non-integrated, enclosed structure for both the heating furnace and furnace tubes. Each furnace and tube has an opening for loading and unloading the material boat. Feeding is achieved simply by operating the furnace cover and furnace tube cover to load and unload the material boat, meeting the needs of mass production, offering high production efficiency, and simplifying operation. Furthermore, the improved device eliminates the need for a complex feeding mechanism and reduces the structural requirements for the material boat and furnace tube. It avoids the stepped material boat and T-shaped furnace tube design found in existing patent CN110694565B, resulting in a simple overall preparation device structure. This simple structure facilitates manufacturing and reduces equipment size. Moreover, this invention does not use valves to control feeding, preventing radioactive gas leakage due to valve leaks. As long as the heating furnace body and furnace cover are sealed, radioactive gas leakage can be avoided. Therefore, this invention effectively reduces the risk of radioactive gas leakage.

[0021] Furthermore, an opening is provided at the top of the heating furnace body;

[0022] The outer wall of the furnace cover is provided with a first annular plate, and the outer wall of the heating furnace body is provided with a second annular plate; the first annular plate and the second annular plate are arranged opposite each other, and when the furnace cover and the heating furnace body are detachably connected, the lower end face of the first annular plate is in sealed contact with the upper end face of the second annular plate.

[0023] The sealed contact described in this invention refers to the provision of a sealing structure between the lower end face of the first annular plate and the upper end face of the second annular plate, so that there is no gap between the two, ensuring that the radioactive gas in the furnace will not leak through the gap between the first annular plate and the second annular plate.

[0024] Furthermore, a first sealing ring is provided between the lower end face of the first annular plate and the upper end face of the second annular plate.

[0025] The aforementioned first sealing ring ensures that there is no gap between the first annular plate and the second annular plate, reducing the risk of leakage.

[0026] Furthermore, the lower end face of the furnace cover is lower than the lower end face of the first annular plate, and the upper end face of the heating furnace body is lower than the upper end face of the second annular plate. When the furnace cover and the heating furnace body are detachably connected, the lower end face of the first annular plate is in sealed contact with the upper end face of the second annular plate, and the upper end face of the heating furnace body is in sealed contact with the lower end face of the furnace cover.

[0027] Conventional designs typically align the lower end of the furnace cover with the lower end of the first annular plate, and the upper end of the heating furnace body with the upper end of the second annular plate. In this invention, the arrangement of the first and second annular plates serves two purposes: firstly, it provides a positioning function, ensuring the lower part of the furnace cover is positioned inside the second annular plate when placed on top of the heating furnace body, thus acting as a guide; secondly, the contact surfaces between the lower end of the furnace cover and the upper end of the heating furnace body are not on the same horizontal plane as the contact surfaces of the first and second annular plates, forming a stepped structure. This stepped structure can reduce the risk of leakage to some extent. Furthermore, the contact surfaces between the lower end of the furnace cover and the upper end of the heating furnace body, along with the contact surfaces of the first and second annular plates, are all in sealed contact. This stepped structure, combined with the double sealing contact, improves the sealing performance between the furnace cover and the heating furnace body, effectively preventing furnace leakage.

[0028] Furthermore, a first sealing ring is provided between the lower end face of the first annular plate and the upper end face of the second annular plate, and a second sealing ring is provided between the upper end face of the furnace body and the lower end face of the furnace cover.

[0029] Furthermore, the dry distillation furnace also includes an inlet pipe and an outlet pipe;

[0030] One end of the air inlet pipe passes through the heating furnace body and is connected to the lower part of the receiving tube body, and is used to introduce gas into the furnace tube.

[0031] One end of the gas outlet pipe passes through the heating furnace body and connects to the upper part of the receiving tube body, and is used to export the gas inside the furnace tube.

[0032] Furthermore, the other end of the air inlet pipe adopts a ground joint design, which is connected to one end of the air pipe through the ground joint, and the other end of the air pipe is connected to the air supply equipment; the other end of the air outlet pipe adopts a ground joint design, which is connected to the pipeline through the ground joint to realize the connection with downstream equipment.

[0033] Furthermore, an air intake valve and an air intake filter are installed on the trachea.

[0034] Furthermore, the intake filter is located at the front end of the intake valve.

[0035] Furthermore, a pressure gauge is installed on the trachea to display the intake pressure.

[0036] Furthermore, the pressure gauge is located at the rear end of the intake valve.

[0037] Furthermore, the furnace tube cover uses a ground joint cover, which ensures the sealing effect of the furnace tube cover at the opening for taking out and putting in the furnace tube.

[0038] Furthermore, both the containment tube and the furnace tube cover are made of quartz glass.

[0039] Furthermore, the top of the receiving tube is an open end forming a loading and unloading port, and the furnace tube cover includes a top cover for closing the loading and unloading port. The outer wall of the top cover is folded down to form an annular baffle, and the inner wall of the annular baffle is in close contact with the outer wall of the receiving tube.

[0040] The aforementioned annular baffle can improve the sealing effect of the furnace tube cover at the loading and unloading port.

[0041] Furthermore, a support frame for fixing the material boat is provided at the inner bottom of the receiving tube, and the support frame has a smaller contact area with the material boat compared to the inner bottom of the receiving tube.

[0042] Because of the support frame, there is a small contact area with the material boat, which can prevent the material boat from sticking to the bottom of the furnace tube.

[0043] Furthermore, the support frame includes at least one support leg.

[0044] Furthermore, the supporting legs are cylindrical structures that are smaller at the top and larger at the bottom.

[0045] Furthermore, the support frame includes a support plate and legs. The legs are located at the bottom of the support plate to support the support plate, so that there is a gap between the support plate and the inner bottom of the receiving tube. The support plate has a hollow structure.

[0046] Furthermore, the furnace cover is provided with a furnace cover handle for cooperating with the robotic arm; the furnace tube cover is provided with a furnace tube cover handle for cooperating with the robotic arm.

[0047] Furthermore, the furnace cover is a metal cover, and a furnace cover insulation layer is provided inside the metal cover.

[0048] Furthermore, the lower end of the furnace cover is recessed upwards to form a groove, which is used to accommodate the furnace tube cover.

[0049] To ensure the temperature inside the furnace, the furnace cover needs to be designed with an insulation structure, resulting in a thicker furnace cover. Setting a groove on the furnace cover will not affect the overall insulation effect, but can reduce the overall size of the preparation device: given a certain thickness of the furnace cover, by setting a groove on the furnace cover to accommodate the furnace tube cover, the height of the heating furnace body can be reduced, so that the top of the heating furnace body does not have to be higher than the furnace tube cover.

[0050] Furthermore, the material boat includes a material boat tray and a material boat handle;

[0051] The material boat tray is used to place materials, and the material boat handle is set on the material boat tray. The material boat handle is used to cooperate with the robot arm.

[0052] Furthermore, it also includes a buffer device and an absorption device arranged sequentially at the rear end of the dry distillation furnace;

[0053] The buffer device is used to capture tellurium dioxide while releasing iodine vapor;

[0054] The absorption device is used to absorb iodine vapor.

[0055] Furthermore, the buffer device includes a buffer bottle and a heating insulation jacket;

[0056] The buffer bottle is placed inside a heating and insulation jacket, and the buffer bottle is connected to the absorption device and the dry distillation furnace through pipes.

[0057] The buffer bottle arrangement in this application is also simpler than the tellurium dioxide trap structure in patent CN110694565B. The tellurium dioxide trap in patent CN110694565B is a coil structure, which is complex. The buffer bottle arrangement of this invention includes a buffer bottle and a heating and insulation jacket. Heating and insulation are achieved through the heating and insulation jacket to ensure that the temperature inside the buffer bottle can meet the requirements for tellurium dioxide condensation, while iodine vapor is maintained in a gaseous state and enters the absorption device. The difference in sublimation temperature between iodine and its compounds and tellurium and its compounds in nuclear physics reactions is used to achieve the separation of tellurium dioxide and iodine.

[0058] Furthermore, the pipe joints utilize a ground joint design.

[0059] Furthermore, the absorption device is a two-stage absorption system. The first-stage absorption uses a 0.1-0.5 mol / L sodium hydroxide solution to absorb iodine vapor, and the second-stage absorption uses a 0.1-1 mol / L sodium hydroxide solution to absorb iodine vapor.

[0060] Furthermore, the absorption device includes an absorption pool, the outer wall of which is provided with a shielding layer.

[0061] Furthermore, a tail gas treatment device is also provided at the rear end of the absorption device, which absorbs the tail gas with a 0.5-5 mol / L sodium hydroxide solution.

[0062] Furthermore, the outer wall of the dry distillation furnace is equipped with an insulation layer.

[0063] Furthermore, it also includes a control system; the control system is used to adjust the heating temperature of the dry distillation furnace and control the heating of the dry distillation furnace.

[0064] Furthermore, the furnace tube, furnace cavity, and material boat are all circular, with the inner diameter of the furnace cavity being larger than the outer diameter of the furnace tube, and the inner diameter of the furnace tube being larger than the outer diameter of the material boat, which helps to reduce the size of the entire preparation device.

[0065] Furthermore, the inner diameter of the furnace tube is 70-160mm, and the height of the furnace tube is 70-150mm; the outer diameter of the material boat is 60-150mm, and the height of the material boat is 50-120mm.

[0066] Furthermore, the boat is a disposable quartz boat.

[0067] Furthermore, it also includes a vacuum pump for evacuating the preparation apparatus, the vacuum pump being located at the end of the preparation apparatus.

[0068] The preparation method based on the above-described preparation apparatus includes the following steps:

[0069] S1. The furnace tube cover and furnace cover are put on sequentially by a robotic arm. The end of the preparation device is evacuated. At the same time, gas is introduced into the front of the preparation device to test the airtightness of the preparation device.

[0070] S2. After the airtightness test is passed, the furnace cover and furnace tube cover are opened in sequence by a robotic arm, and the material boat containing the irradiated target material is placed into the furnace tube.

[0071] S3. Using a robotic arm, the furnace tube cover and furnace cover are sequentially covered, and the end of the preparation device is evacuated. At the same time, the dry distillation furnace starts to heat up, and the furnace temperature rises. When the temperature reaches 750-800℃, constant temperature heating is carried out, and the tellurium dioxide melts, releasing tellurium dioxide vapor and iodine vapor.

[0072] S4. Use carrier gas to guide tellurium oxide vapor and iodine vapor out of the dry distillation furnace for subsequent separation processing;

[0073] S5. After the reaction is complete, the dry distillation furnace begins to cool down. Once the dry distillation furnace has cooled to room temperature, the evacuation stops. The furnace cover and furnace tube cover are opened sequentially using a robotic arm to remove the material boat.

[0074] Repeat steps S1-S5 to continue production.

[0075] Furthermore, in step S3, the heating rate is 0-10℃ / min; the temperature control accuracy is ±1℃.

[0076] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0077] 1. This invention, by not making the heating furnace and furnace tubes an integral closed structure, has openings and ports for loading and unloading material boats in both the heating furnace and furnace tubes. Material can be fed simply by operating the furnace cover and furnace tube cover to load and unload the material boats. This not only meets the needs of mass production and has high production efficiency, but also has a simple and easy-to-operate structure, which can reduce the size of the equipment and effectively reduce the risk of radioactive gas leakage.

[0078] 2. This invention, by placing the lower end face of the furnace cover below the lower end face of the first annular plate and the upper end face of the heating furnace body below the upper end face of the second annular plate, serves two purposes: firstly, it provides a certain positioning function, guiding the furnace cover when it closes the opening; secondly, it creates a stepped structure between the contact surfaces of the lower end face of the furnace cover and the upper end face of the heating furnace body and the contact surfaces of the first and second annular plates. This stepped structure, combined with a double-seal contact, improves the sealing performance between the furnace cover and the heating furnace body, effectively preventing furnace leakage.

[0079] 3. The present invention provides a support frame for fixing the material boat at the bottom of the inner part of the accommodating tube, which can prevent the material boat from sticking to the bottom of the furnace tube.

[0080] 4. The material boat of the present invention adopts a special design; it includes a material boat tray and a material boat handle, and the furnace cover is provided with a furnace cover handle for cooperating with the robot arm; the furnace tube cover is provided with a furnace tube cover handle for cooperating with the robot arm. The material boat can be taken out and put into the furnace tube by directly operating the material boat handle, the furnace cover handle and the furnace tube cover handle by the robot arm, which improves the convenience of operation. Attached Figure Description

[0081] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0082] Figure 1 This is a structural block diagram of the apparatus for preparing radioactive iodine-131 according to the present invention;

[0083] Figure 2 This is a schematic diagram of the apparatus for preparing radioactive iodine-131 according to the present invention;

[0084] Figure 3 This is a magnified view of the connection between the furnace cover and the heating furnace body.

[0085] The attached diagram shows the markings and corresponding component names:

[0086] 1-Diesel furnace; 2-Buffer device; 3-Absorption device; 4-Tail gas treatment device; 5-Control system; 6-Outlet pipe; 7-Heating furnace body; 8-Furnace tube; 9-Furnace cover handle; 10-Furnace cover insulation layer; 11-Furnace cover; 12-Burning boat handle; 13-Burning boat tray; 14-Inlet pipe; 15-Insulation layer; 16-Gas pipe; 17-Support frame; 18-Pressure gauge; 19-Inlet valve; 20-Inlet filter; 21-First gas outlet pipe; 22-First gas inlet pipe; 23-Vacuum pump; 24-First annular plate; 25-Second annular plate. Detailed Implementation

[0087] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0088] Example 1:

[0089] like Figures 1-3 As shown, an apparatus for preparing radioactive iodine-131 includes a dry distillation furnace 1, which includes a heating furnace and furnace tubes 8.

[0090] The heating furnace includes a furnace body 7 and a furnace cover 11. A thermocouple and a heating resistance wire are installed inside the furnace body 7. The heating resistance wire is used to heat the furnace cavity, and the thermocouple is used to detect the temperature. Heating stops when the temperature reaches a set value. A furnace cavity is formed within the furnace body 7, and an opening is provided on the furnace body 7 to allow communication between the furnace cavity and the external space. The furnace cover 11 is detachably connected to the furnace body 7 to seal the opening.

[0091] The opening on the heating furnace body 7 is for loading and unloading the material boat. The form of the opening is not limited. In a specific implementation, the top of the heating furnace body 7 forms an opening, and the furnace cover 11 is placed directly on the top of the heating furnace body 7 to close the opening. The top of the heating furnace body 7 and the bottom of the furnace cover 11 are in sealed contact.

[0092] The furnace tube 8 is placed inside the furnace cavity. The furnace tube 8 can be a quartz tube. The furnace tube 8 includes a receiving tube body and a furnace tube cover. The receiving tube body is used to place the material boat. The receiving tube body is provided with a loading and unloading port for loading and unloading the material boat. The furnace tube cover is detachably connected to the receiving tube body to close the loading and unloading port.

[0093] The constant temperature zone of the distillation furnace 1 in this embodiment is adjustable from 700 to 800°C, with a maximum control temperature of 1000°C and a constant temperature accuracy of ±1°C. The heating wires and insulation materials contained in the furnace body have a service life of ≥5000h within the range of 700-800°C, and a heating rate of 0-10°C / min.

[0094] The loading and unloading port on the receiving tube is for loading and unloading the material boat. Its arrangement is not limited. In one specific implementation, the top of the receiving tube forms an opening, and the furnace tube cover is placed directly on top of the receiving tube to seal the loading and unloading port. To improve the sealing at the connection between the furnace tube cover and the receiving tube, the furnace tube cover is a ground-joint cover, and the loading and unloading port is also designed with a ground joint. To further improve the sealing at the connection between the furnace tube cover and the receiving tube, in a preferred embodiment, the furnace tube cover includes a top cover for sealing the loading and unloading port. The outer wall of the top cover is folded downwards to form an annular baffle, and the inner wall of the annular baffle is in close contact with the outer wall of the receiving tube.

[0095] This embodiment features a non-integrated, enclosed structure for both the heating furnace and furnace tube 8. Each furnace and tube has an opening for loading and unloading the material boat. Feeding is achieved simply by operating the furnace cover 11 and furnace tube cover to load and unload the material boat, meeting the needs of mass production, offering high production efficiency, and simplifying operation. Furthermore, the improved preparation device eliminates the need for a complex feeding mechanism and lowers the structural requirements for the material boat and furnace tube 8. It avoids the stepped material boat and T-shaped furnace tube design found in existing patent CN110694565B, resulting in a simpler overall structure. This simplicity facilitates manufacturing and reduces the overall size of the preparation device. Additionally, this embodiment does not use valves to control feeding, preventing radioactive gas leakage due to valve leaks. As long as the heating furnace body 7 and furnace cover 11 are sealed, radioactive gas leakage can be avoided. Therefore, this embodiment effectively reduces the risk of radioactive gas leakage.

[0096] To facilitate the introduction and export of gas into and out of the furnace tube 8, the dry distillation furnace 1 further includes an inlet pipe 14 and an outlet pipe 6. One end of the inlet pipe 14 passes through the heating furnace body 7 and connects to the lower part of the receiving tube body, for introducing gas into the furnace tube 8. The other end of the inlet pipe 14 has a ground joint design, which connects to one end of a gas pipe 16. The other end of the gas pipe 16 is connected to a gas supply device, and an inlet valve 19 is provided on the gas pipe 16. Preferably, a pressure gauge 18 and an inlet filter 20 are also provided on the gas pipe 16. The pressure gauge 18 is used to display the inlet pressure, and the inlet filter 20 is used to filter the gas. Preferably, the inlet filter 20 is located at the front end of the inlet valve 19 to reduce damage to the inlet valve 19 by the gas. The pressure gauge 18 is located at the rear end of the inlet valve 19 to improve the accuracy of pressure monitoring. In this embodiment, the front end and the rear end refer to the direction of gas flow.

[0097] One end of the gas outlet pipe 6 passes through the heating furnace body 7 and connects to the upper part of the receiving tube body to export the gas in the furnace tube 8; the other end of the gas outlet pipe 6 adopts a ground joint design and is connected to the pipeline through the ground joint to realize the connection with downstream equipment.

[0098] In this embodiment, the downstream equipment includes a buffer device 2 and an absorption device 3 arranged sequentially at the rear end of the dry distillation furnace 1; the buffer device 2 is used to capture tellurium dioxide while releasing iodine vapor; the absorption device 3 is used to absorb iodine vapor; the buffer device 2 utilizes the difference in sublimation temperature between iodine and its compounds and tellurium and its compounds in nuclear physics reactions to achieve the separation of tellurium dioxide and iodine.

[0099] In one specific implementation, the buffer device 2 includes a buffer bottle and a heating and insulation jacket. The buffer bottle is placed inside the heating and insulation jacket and is connected to the absorption device 3 and the dry distillation furnace 1 through a pipe. Specifically, the buffer bottle is provided with a first gas inlet pipe 22 and a first gas outlet pipe 21. One end of the first gas inlet pipe 22 is inserted into the lower part of the buffer bottle, and the other end is connected to the gas outlet pipe 6. The connection is designed with a ground joint. The first gas outlet pipe 21 is connected to the absorption device 3 through a connecting pipe. The connection is also designed with a ground joint.

[0100] In one specific implementation, the absorption device 3 is a two-stage absorption system. The first-stage absorption uses a 0.1-0.5 mol / L sodium hydroxide solution to absorb iodine vapor, and the second-stage absorption uses a 0.1-1 mol / L sodium hydroxide solution to absorb iodine vapor. Specifically, the absorption device 3 includes two absorption tanks, each equipped with a second gas inlet pipe, a second gas outlet pipe, a liquid addition pipe, and a liquid extraction pipe. The second gas inlet pipe is connected to the first gas outlet pipe 21 via a connecting pipe. The liquid addition pipe is used to add absorbent to the absorption tank, and the liquid extraction pipe is used to remove liquid from the absorption tank. Preferably, a shielding layer is provided on the outer wall of the absorption tank.

[0101] In a preferred embodiment, a tail gas treatment device 4 is further provided at the rear end of the absorption device 3. The tail gas treatment device 4 absorbs the tail gas with a 0.5-5 mol / L sodium hydroxide solution, and the second gas outlet pipe is connected to the tail gas treatment device 4.

[0102] The material boat described in this embodiment is a disposable quartz boat.

[0103] In this embodiment, a vacuum pump 23 for evacuating the preparation device is also included. The vacuum pump 23 is located at the end of the preparation device, that is, the vacuum pump 23 is connected to the pipe at the very end of the preparation device.

[0104] In a preferred embodiment, a preferred sealing connection between the heating furnace body 7 and the furnace cover 11 is as follows:

[0105] The outer wall of the furnace cover 11 is provided with a first annular plate 24, and the outer wall of the heating furnace body 7 is provided with a second annular plate 25. The first annular plate 24 and the second annular plate 25 are arranged vertically opposite each other. When the furnace cover 11 is placed on the heating furnace body 7, the lower end face of the first annular plate 24 is in sealing contact with the upper end face of the second annular plate 25. Specifically, a first sealing ring can be provided between the lower end face of the first annular plate 24 and the upper end face of the second annular plate 25. More specifically, a first semi-circular groove and a second semi-circular groove can be provided on the lower end face of the first annular plate 24 and the upper end face of the second annular plate 25, respectively. In use, the first sealing ring can be embedded in the first semi-circular groove, and when the furnace cover 11 is placed on the heating furnace body 7, the lower end face of the first sealing ring is embedded in the second semi-circular groove.

[0106] In a preferred embodiment, the lower end face of the furnace cover 11 is lower than the lower end face of the first annular plate 24, and the upper end face of the heating furnace body 7 is lower than the upper end face of the second annular plate 25. When the furnace cover 11 and the heating furnace body 7 are detachably connected, the lower end face of the first annular plate 24 is in sealed contact with the upper end face of the second annular plate 25, and the upper end face of the heating furnace body 7 is in sealed contact with the lower end face of the furnace cover 11. Specifically, a first sealing ring can be provided between the lower end face of the first annular plate 24 and the upper end face of the second annular plate 25, and a second sealing ring can be provided between the upper end face of the heating furnace body 7 and the lower end face of the furnace cover 11. The fixing method of the first sealing ring and the second sealing ring is the same as above.

[0107] In this embodiment, the lower end face of the furnace cover 11 is lower than the lower end face of the first annular plate 24, and the upper end face of the heating furnace body 7 is lower than the upper end face of the second annular plate 25. On the one hand, this has a certain positioning function, which guides the furnace cover 11 when it closes the opening. On the other hand, it forms a stepped structure between the contact surface of the lower end face of the furnace cover 11 and the upper end face of the heating furnace body 7 and the contact surface of the first annular plate 24 and the second annular plate 25. The contact surface of the stepped structure, combined with the double sealing contact, improves the connection and sealing between the furnace cover 11 and the heating furnace body 7, and effectively avoids the problem of furnace leakage.

[0108] In a preferred embodiment, a support frame 17 for fixing the material boat is provided at the inner bottom of the receiving tube. The support frame 17 has a smaller contact area with the material boat compared to the inner bottom of the receiving tube. Specifically, the support frame 17 may include at least one support leg, and more specifically, three support legs may be used, with the tops of the three support legs jointly supporting the material boat. Preferably, the support leg is a column with a smaller top and a larger bottom, i.e., the support leg can be a frustum of a cone or a polyhedron structure with a smaller top and a larger bottom. The support frame 17 may also include a support plate and legs, with the legs positioned at the bottom of the support plate to support the support plate, creating a gap between the support plate and the inner bottom of the receiving tube. The support plate may be a perforated structure.

[0109] In a preferred embodiment, to facilitate the operation of the robotic arm in picking up and placing the material boat, the furnace cover 11 is provided with a furnace cover handle 9 for cooperating with the robotic arm; the furnace tube cover is provided with a furnace tube cover handle for cooperating with the robotic arm. The material boat includes a material boat tray 13 and a material boat handle 12; the material boat tray 13 is used to place materials, and the material boat handle 12 is disposed on the material boat tray 13 and is used to cooperate with the robotic arm.

[0110] In a preferred embodiment, to ensure the heat preservation of the dry distillation furnace 1, the furnace cover 11 is a metal cover, and a furnace cover insulation layer 10 is provided inside the metal cover. This can be achieved by having a sandwich structure inside the metal cover with the furnace cover insulation layer 10 placed within the sandwich structure, or by directly placing the furnace cover insulation layer 10 inside the metal cover. A heat preservation layer 15 is provided on the outer wall of the dry distillation furnace 1.

[0111] In a preferred embodiment, the lower end of the furnace cover 11 is recessed upwards to form a groove, which is used to accommodate the furnace tube cover. Providing a groove on the furnace cover 11 does not significantly affect the overall insulation effect, but it reduces the overall size of the preparation device: given a fixed thickness of the furnace cover 11, by providing a groove on the furnace cover 11 to accommodate the furnace tube cover, the height of the heating furnace body 7 can be reduced, eliminating the need for the top of the heating furnace body 7 to be higher than the furnace tube cover 11.

[0112] To further reduce the overall size of the preparation apparatus, the shape and size of furnace tube 8, furnace cavity, and material boat were optimized:

[0113] The furnace tube 8, furnace cavity, and material boat are all circular. The inner diameter of the furnace cavity is larger than the outer diameter of the furnace tube 8, and the inner diameter of the furnace tube 8 is larger than the outer diameter of the material boat. Specifically, the inner diameter of the furnace tube 8 is 70-160mm, the height of the furnace tube 8 is 70-150mm, and the material is quartz glass; the outer diameter of the material boat is 60-150mm, the height of the material boat is 50-120mm, and the material is quartz glass.

[0114] In a preferred embodiment, in order to achieve automatic control, a control system 5 is also included; the control system 5 is used to adjust the heating temperature of the dry distillation furnace 1 and control the dry distillation furnace 1 to perform heating.

[0115] The preparation method of the preparation device described in this embodiment includes the following steps:

[0116] S1. Using a robotic arm, the furnace tube cover and furnace cover 11 are sequentially covered. The vacuum pump 23 is started to evacuate the preparation device and air is introduced from the air inlet 14. The air tightness of the preparation device is then checked.

[0117] S2. After the airtightness test is passed, the furnace cover 11 and the furnace tube cover are opened in sequence by a robotic arm, and the boat containing the irradiated target material is placed into the furnace tube 8.

[0118] S3. Using a robotic arm, the furnace tube cover and furnace cover 11 are sequentially covered. The vacuum pump 23 is started to evacuate the preparation device. At the same time, the dry distillation furnace 1 starts heating, and the furnace temperature rises. When the temperature reaches 750-800℃, constant temperature heating is performed. Tellurium dioxide melts and releases tellurium dioxide vapor and iodine vapor. The heating rate is 0-10℃ / min; the constant temperature accuracy is ±1℃.

[0119] S4. Using carrier gas to export tellurium dioxide vapor and iodine vapor from the dry distillation furnace 1 for subsequent separation: the carrier gas carries the mixed gas through the outlet pipe 6 to the buffer device 2. The temperature of the buffer device 2 is heated to 100-150℃. The tellurium dioxide vapor condenses in the buffer device 2, and the iodine vapor continues to pass into the absorption device 3.

[0120] S5. After the reaction is complete, the dry distillation furnace 1 begins to cool down. After the dry distillation furnace 1 cools down to room temperature, the gas extraction stops. The furnace cover 11 and the furnace tube cover are opened in sequence by a robotic arm, and the material boat is taken out.

[0121] Repeat steps S1-S5 to continue production.

[0122] This embodiment utilizes 130 Te(n, γ) 131 Te(β - ) 131 By utilizing the nuclear physics reactions of iodine and its compounds, and the difference in sublimation temperatures between iodine and tellurium and its compounds, iodine vapor is obtained from activated tellurium dioxide feedstock through a dry distillation method with controlled heating temperature. This vapor is then absorbed by a downstream vapor absorption device to generate medical-grade sodium hydroxide. 131 I. Solution product.

[0123] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0124] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the disclosed technical content. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

Claims

1. An apparatus for preparing radioactive iodine-131, comprising a dry distillation furnace (1), said dry distillation furnace (1) comprising a heating furnace and furnace tubes (8); characterized in that, The heating furnace includes a heating furnace body (7) and a furnace cover (11). A furnace cavity is formed inside the heating furnace body (7). An opening is provided on the heating furnace body (7) to enable communication between the furnace cavity and the external space. The furnace cover (11) is detachably connected to the heating furnace body (7) to close the opening. The furnace tube (8) is placed inside the furnace cavity. The furnace tube (8) includes a receiving tube body and a furnace tube cover. The receiving tube body is used to place the material boat. The receiving tube body is provided with a loading and unloading port for loading and unloading the material boat. The furnace tube cover is detachably connected to the receiving tube body to close the loading and unloading port. An opening is provided at the top of the heating furnace body (7); The outer wall of the furnace cover (11) is provided with a first annular plate (24), and the outer wall of the heating furnace body (7) is provided with a second annular plate (25); the first annular plate (24) and the second annular plate (25) are arranged opposite each other, and when the furnace cover (11) and the heating furnace body (7) are detachably connected, the lower end face of the first annular plate (24) is in sealed contact with the upper end face of the second annular plate (25); A first sealing ring is provided between the lower end face of the first annular plate (24) and the upper end face of the second annular plate (25); The lower end face of the furnace cover (11) is lower than the lower end face of the first annular plate (24), and the upper end face of the heating furnace body (7) is lower than the upper end face of the second annular plate (25). When the furnace cover (11) and the heating furnace body (7) are detachably connected, the lower end face of the first annular plate (24) is in sealed contact with the upper end face of the second annular plate (25), and the upper end face of the heating furnace body (7) is in sealed contact with the lower end face of the furnace cover (11). A first sealing ring is provided between the lower end face of the first annular plate (24) and the upper end face of the second annular plate (25), and a second sealing ring is provided between the upper end face of the hot furnace body (7) and the lower end face of the furnace cover (11). The top of the receiving tube is an open end forming a loading and unloading port. The furnace tube cover includes a top cover for closing the loading and unloading port. The outer wall of the top cover is folded down to form an annular baffle. The inner wall of the annular baffle is in close contact with the outer wall of the receiving tube. The material boat includes a material boat tray (13) and a material boat handle (12); The material boat tray (13) is used to place materials, and the material boat handle (12) is set on the material boat tray (13). The material boat handle (12) is used to cooperate with the robot arm. It also includes a buffer device (2) and an absorption device (3) arranged sequentially at the rear end of the dry distillation furnace (1); The buffer device (2) is used to capture tellurium dioxide while releasing iodine vapor; The absorption device (3) is used to absorb iodine vapor; The buffer device (2) includes a buffer bottle and a heating and insulation jacket; The buffer bottle is placed inside a heating and insulation jacket, and the buffer bottle is connected to the absorption device (3) and the dry distillation furnace (1) through pipes.

2. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The dry distillation furnace (1) also includes an inlet pipe (14) and an outlet pipe (6); One end of the air inlet pipe (14) passes through the heating furnace body (7) and is connected to the lower part of the receiving tube body, for introducing gas into the furnace tube (8); One end of the gas outlet pipe (6) passes through the heating furnace body (7) and is connected to the upper part of the receiving tube body, and is used to export the gas in the furnace tube (8).

3. The apparatus for preparing radioactive iodine-131 according to claim 2, characterized in that, The other end of the air inlet pipe (14) adopts a ground joint design, which is connected to one end of the air pipe (16) through the ground joint. The other end of the air pipe (16) is connected to the air supply equipment. The other end of the air outlet pipe (6) adopts a ground joint design, which is connected to the pipeline through the ground joint to realize the connection with the downstream equipment.

4. The apparatus for preparing radioactive iodine-131 according to claim 3, characterized in that, The air pipe (16) is equipped with an air inlet valve (19) and an air inlet filter (20).

5. The apparatus for preparing radioactive iodine-131 according to claim 4, characterized in that, The intake filter (20) is located at the front end of the intake valve (19).

6. The apparatus for preparing radioactive iodine-131 according to claim 4, characterized in that, The trachea (16) is also equipped with a pressure gauge (18) for displaying the intake pressure.

7. The apparatus for preparing radioactive iodine-131 according to claim 6, characterized in that, The pressure gauge (18) is located at the rear end of the air intake valve (19).

8. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The furnace tube cover is a ground joint cover.

9. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, Both the containment tube and the furnace tube cover are made of quartz glass.

10. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The inner bottom of the receiving tube is provided with a support frame (17) for fixing the material boat. The support frame (17) has a smaller contact area with the material boat compared to the inner bottom of the receiving tube.

11. The apparatus for preparing radioactive iodine-131 according to claim 10, characterized in that, The support frame (17) includes at least one support leg.

12. The apparatus for preparing radioactive iodine-131 according to claim 11, characterized in that, The supporting leg is a column that is smaller at the top and larger at the bottom.

13. The apparatus for preparing radioactive iodine-131 according to claim 11, characterized in that, The support frame (17) includes a support plate and legs. The legs are located at the bottom of the support plate to support the support plate, so that there is a gap between the support plate and the inner bottom of the accommodating tube. The support plate has a hollow structure.

14. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The furnace cover (11) is provided with a furnace cover handle (9) for cooperating with the robot arm; the furnace tube cover is provided with a furnace tube cover handle for cooperating with the robot arm.

15. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The furnace cover (11) is a metal cover, and a furnace cover heat insulation layer (10) is provided inside the metal cover.

16. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The lower end of the furnace cover (11) is recessed upward to form a groove, which is used to accommodate the furnace tube cover.

17. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The pipe joints are designed with ground joints.

18. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The absorption device (3) is a two-stage absorption device. The first-stage absorption uses 0.1-0.5 mol / L sodium hydroxide solution to absorb iodine vapor, and the second-stage absorption uses 0.1-1 mol / L sodium hydroxide solution to absorb iodine vapor.

19. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The absorption device (3) includes an absorption pool, and a shielding layer is provided on the outer wall of the absorption pool.

20. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The rear end of the absorption device (3) is also provided with a tail gas treatment device (4), which uses a 0.5-5 mol / L sodium hydroxide solution to absorb the tail gas.

21. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, The outer wall of the dry distillation furnace (1) is provided with a heat insulation layer (15).

22. The apparatus for preparing radioactive iodine-131 according to claim 1, characterized in that, It also includes a control system (5); the control system (5) is used to adjust the heating temperature of the dry distillation furnace (1) and control the dry distillation furnace (1) to heat.

23. The apparatus for preparing radioactive iodine-131 according to any one of claims 1-22, characterized in that, The furnace tube (8), furnace cavity, and material boat are all circular. The inner diameter of the furnace cavity is larger than the outer diameter of the furnace tube (8), and the inner diameter of the furnace tube (8) is larger than the outer diameter of the material boat.

24. The apparatus for preparing radioactive iodine-131 according to claim 23, characterized in that, The inner diameter of the furnace tube (8) is 70-160mm, and the height of the furnace tube (8) is 70-150mm; the outer diameter of the material boat is 60-150mm, and the height of the material boat is 50-120mm.

25. An apparatus for preparing radioactive iodine-131 according to any one of claims 1-22, characterized in that, The material boat is a disposable quartz boat.

26. An apparatus for preparing radioactive iodine-131 according to any one of claims 1-22, characterized in that, It also includes a vacuum pump (23) for evacuating the preparation apparatus, the vacuum pump (23) being located at the end of the preparation apparatus.

27. The method for preparing radioactive iodine-131 according to any one of claims 1-26, characterized in that, Includes the following steps: S1. The furnace tube cover and furnace cover (11) are put on sequentially by a robotic arm. The end of the preparation device is evacuated. At the same time, gas is introduced into the front end of the preparation device to test the airtightness of the preparation device. S2. After the airtightness test is passed, the furnace cover (11) and furnace tube cover are opened in sequence by using a robotic arm, and the material boat containing the irradiated target material is placed into the furnace tube (8). S3. The furnace tube cover and furnace cover (11) are put on in sequence by using a robotic arm. The end of the preparation device is evacuated. At the same time, the dry distillation furnace (1) starts to heat up and the furnace temperature rises. When the temperature rises to 750-800℃, constant temperature heating is carried out. Tellurium dioxide melts and releases tellurium dioxide vapor and iodine vapor. S4. Use carrier gas to export tellurium oxide vapor and iodine vapor to the dry distillation furnace (1) for subsequent separation processing; S5. After the reaction is complete, the dry distillation furnace (1) begins to cool down. After the dry distillation furnace (1) cools down to room temperature, the gas extraction stops. The furnace cover (11) and the furnace tube cover are opened in sequence by a robotic arm, and the material boat is taken out. Repeat steps S1-S5 to continue production.

28. The preparation method according to claim 27, characterized in that, In step S3, the heating rate is 0-10℃ / min; the temperature control accuracy is ±1℃.

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