A purification system, purification method and application of activator for cesium iodide scintillating screen

Abstract

The present invention belongs to the technical field of purification of activators for cesium iodide scintillating screens, and specifically relates to a purification system, purification method, and application of activators for cesium iodide scintillating screens. The activator purification system provided by the present invention includes a heating and separation device for separating solid activators for cesium iodide scintillating screens and a heating and melting device for further purifying the solid activators. The heating and separation device is mainly used to remove cesium iodide and impurities such as furnace wall dust, metal particles, and glass particles from waste materials. The heating and melting device melts and evaporates the separated activators, removes residual impurities again, and obtains a high-purity activator. In addition, the present invention also provides an activator purification method, which achieves the purpose of purifying the activator through heating and dissolving, screening and filtering, pure water washing, melting and evaporating, and condensing and collecting. The entire purification process is environmentally friendly and safe, does not generate secondary pollution, and the purified activator can be directly used in the production of cesium iodide crystal single crystals and the preparation of cesium iodide scintillating screens.

Description

Technical Field

[0001] The invention belongs to the technical field of purification of activators for cesium iodide scintillating screens, and in particular relates to a purification system, a purification method and an application of an activator for cesium iodide scintillating screens. Background Art

[0002] The activator for cesium iodide scintillator screens is an inorganic halide. To improve the stability and performance of cesium iodide scintillator screens, the activator is added to the cesium iodide raw material. After mixing, the screen is prepared through a thermal evaporation process.

[0003] The above-mentioned process generates solid waste containing a large amount of activator after evaporation. The activator for cesium iodide thin-film scintillator screens contains halides of thallium, bismuth, and ytterbium ions, all of which are highly toxic and hazardous elements. Thallium and its compounds are mutagenic, teratogenic, and carcinogenic to organisms. Thallium poisoning can cause symptoms such as dizziness, fatigue, and vomiting, and in severe cases, can even cause epilepsy and blindness. Therefore, it is necessary to recycle and treat thallium-containing solid waste.

[0004] Common treatment methods primarily involve separating soluble thallium ions through extraction and adsorption. However, organic extraction processes are lengthy and complex, while stripping thallium ions is difficult and inefficient. This process generates large amounts of organic wastewater, creating challenges in secondary wastewater treatment. Currently, most manufacturers prefer to selectively adsorb thallium using specific resins. This adsorption process is difficult to operate, and the thallium-containing resins after adsorption also require hazardous waste disposal, creating secondary pollution. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides an activator purification system, purification method and application for cesium iodide scintillator screens. The purpose is to filter and recover activator filter cakes from waste materials in an environmentally friendly manner. The activator material obtained through a melting purification step is high in purity and can be used for the production of cesium iodide crystal activator single crystals. The purified activator material is fully suitable for use in high-performance cesium iodide scintillator screens, achieving the effects of material recycling, resource conservation, cost reduction and efficiency improvement.

[0006] The present invention provides an activator purification system for a cesium iodide scintillation screen, comprising a heating and separating device for separating an activator filter cake from a raw material containing the activator and a heating and melting device for evaporating and purifying the activator filter cake; the heating and separating device comprises a bracket, a tank body, an agitator, a filtering device, and a supporting telescopic tube; the tank body is fixedly mounted on the bracket; the tank body is provided with a feeding port and an open bottom; a through-hole is provided at the top of the tank body; the agitator comprises a stirring shaft and a stirring head; the stirring shaft passes through the through-hole into the interior of the tank body and is sealed with the through-hole; the filtering device comprises a piston and a filtering assembly; the piston comprises a piston body and a piston cavity located in the piston body; the piston is movably mounted in the tank body and is sealed to the inner wall of the tank body; the top of the piston body is open and the bottom is provided with a drain valve; the filtering assembly is arranged in the piston cavity; the filtering assembly contains at least three levels of screens and a layer of filter cloth; the telescopic supporting tube is fixedly connected to the bottom of the piston body; and the telescopic supporting tube is fixedly connected to the bracket.

[0007] The activator purification system can be used to purify and recycle cesium iodide crystals and waste materials generated after vapor deposition. The activator purification system consists of two parts: a heating and separation device and a heating and melting device. The heating and separation device is primarily used to remove cesium iodide from the waste material, as well as impurities such as furnace wall dust, metal particles, and glass particles. The heating and melting device melts and evaporates the separated activator, further removing residual impurities to produce a high-purity activator. The waste material is placed in a tank. After adjusting the reaction conditions, it is stirred and heated to completely dissolve the cesium iodide in the waste material in pure water. The activator remains in a granular precipitate. The cesium iodide aqueous solution is discharged through a filtration device. Most of the dust, metal particles, and glass particles, and other impurities, are intercepted by a screen, while the activator is retained by a filter cloth. The activator filter cake after screening and filtration is thoroughly washed to remove residual cesium iodide salts. After drying, a solid activator is obtained. The support telescopic tube is controlled to compress, driving the piston to withdraw from the bottom of the tank, facilitating the removal of the solid activator.

[0008] Furthermore, the tank body is a jacketed heating tank body, which is heated by an oil bath and is made of alloy material; the top of the tank body is also provided with an air pump port, a water inlet and a sensor insertion port; the agitator is made of alloy material; the stirring shaft and the stirring head are detachably connected, and the stirring head is a paddle-type stirring blade.

[0009] The jacketed heating tank allows the reactants to be fully mixed through the agitator, increasing the reaction rate and accelerating the process. At the same time, the temperature of the reaction system is controlled by oil as a medium, providing a stable heat source while ensuring that the reaction is precisely controlled within the set temperature range, thereby increasing safety. The alloy material has the advantages of high temperature resistance and strong corrosion resistance.

[0010] The gas in the tank can be effectively removed through the vacuum pump port to avoid the influence of the gas. The water inlet is set to facilitate direct washing of the filter cake. The sensor insertion port is set to measure the pressure and temperature in the tank. It can accurately monitor the changes in pressure and temperature in the tank and improve the safety of the equipment.

[0011] The stirring shaft and stirring head are detachably connected for easy cleaning. The stirring head uses paddle-type stirring blades, which can effectively mix liquid and solid substances evenly. It occupies a small area and is easy to maintain. The alloy material has the advantages of high temperature resistance and strong corrosion resistance.

[0012] Furthermore, the mesh number of the screen is 30-325 meshes and is made of alloy material; the mesh number of the filter cloth is greater than 10,000 meshes and is made of high-temperature resistant plastic material; the filter cloth is arranged on a layer of screen near the bottom of the piston body 1411.

[0013] The mesh size of the filter assembly 142 can ensure that impurities such as furnace wall dust, metal particles, glass particles, etc. are effectively intercepted, but the activator cannot be intercepted. The pore size design of the filter cloth layer can effectively intercept the activator to achieve the separation purpose.

[0014] The filter cloth is arranged on the screen and can support the filter cloth.

[0015] Furthermore, a lifting mechanism is fixedly installed on the side of the bracket, and the lifting mechanism is fixedly connected to the agitator; mounting platforms are provided in the middle and bottom of the bracket, and the mounting platform in the middle position is fixedly installed on the tank body; the mounting platform at the bottom is fixedly installed to support the telescopic tube; a pulley is provided at the bottom of the bracket.

[0016] The lifting mechanism allows the stirrer to flexibly adjust the height and position of the stirring head according to different stirring requirements, thereby improving stirring efficiency. A pulley is provided at the bottom of the bracket to facilitate the movement of the equipment.

[0017] The tank body and supporting telescopic tube are installed on the mounting platform to ensure the stability of the entire equipment. Pulleys are provided at the bottom of the bracket to facilitate the movement of the equipment.

[0018] Furthermore, the heating and melting equipment includes a boiler, an operating box and a support frame, wherein at least part of the boiler is arc-shaped; a quartz glass pipe is provided in the boiler; both ends of the quartz glass pipe are open, one end is a feed port, and the other end is open downward and connected to a collection bottle; the quartz glass pipe passes through at least three adjustable temperature zones; the support frame is fixedly installed with the operating box and the collection bottle.

[0019] At least part of the boiler is curved. The curved pipe redirects the internal gas flow, reduces stress on the pipe, and increases its service life. The end of the quartz glass pipe connected to the collection flask is open downward, facilitating material collection. The solid activator is placed in a heating and melting device and passes through three different temperature zones. The different boiling points of the substances allow for better vaporization and impurity removal. Simultaneously, the gaseous activator is converted into liquid activator, which flows through the quartz glass pipe opening into the collection flask, resulting in a high-purity activator that can be reused in the preparation of cesium iodide scintillation screens, which also involve the activator.

[0020] Furthermore, the collecting bottle is provided with an air extraction port.

[0021] Through the exhaust port, the excess gas in the equipment can be effectively removed to avoid the impact of gas.

[0022] Furthermore, the support frame includes a support platform and a support column; the operation box is arranged on the support platform; the collection bottle is arranged on the support column; and a pulley is provided at the bottom of the support frame.

[0023] The operating box and collecting bottle are installed on the supporting platform and supporting column respectively to ensure the stability of the whole equipment. The supporting frame is equipped with pulleys to facilitate the movement of the equipment.

[0024] Furthermore, a method for purifying an activator is provided, characterized in that it comprises the following steps:

[0025] Step (1): placing the waste material containing the activator and cesium iodide in a closed container, adding pure water, stirring and heating to dissolve under a vacuum state, and stopping stirring when the cesium iodide is completely dissolved in the pure water to obtain a mixed slurry containing the activator and cesium iodide;

[0026] Step (2): subjecting the mixed slurry containing the activator and cesium iodide obtained in step (1) to multi-stage screening and filtering, and separating the activator filter cake at the bottom layer;

[0027] Step (3): washing and drying the activator filter cake obtained in step (2) to obtain a solid activator;

[0028] Step (4): The solid activator obtained in step (3) is subjected to multi-stage melting heating to convert the solid activator into a gaseous activator first and then into a liquid activator, and then cooled to obtain a highly pure activator solid.

[0029] Furthermore, a method for purifying an activator is provided, characterized in that it comprises the following steps:

[0030] S1. The waste raw material containing the activator and cesium iodide is put into the tank from the feeding port, pure water is added at a material-liquid ratio of 1:6-10, vacuuming is first performed from the vacuum pump port on the top of the tank, the stirring device is started, and the temperature is raised to 110-140° C. in an oil bath. The waste raw material is heated for 2-3 hours to completely dissolve the cesium iodide in the pure water, and the stirring is stopped to obtain a mixed slurry containing the activator and cesium iodide;

[0031] S2. The mixed slurry containing the activator and cesium iodide is subjected to multi-stage screening and filtration by a filtration device. The cesium iodide aqueous solution passes through the screen and filter cloth of the filter assembly and is discharged through the drain valve at the bottom of the piston body, while the activator is retained on the filter cloth.

[0032] S3. Pump pure water into the water inlet on the top of the tank to wash the activator until the conductivity of the washed water is less than 10us / cm;

[0033] S4. Pumping inert gas from the vacuum pump port on the top of the tank body to pressurize and dehydrate the activator to obtain a solid activator;

[0034] S5. Transfer the solid activator obtained in S4 into the feed port of the heating and melting equipment, set the temperature, heat for 2-3 hours, open the vacuum port, and vacuum for 10-12 hours. Set the heating temperature again, heat for 8-12 hours, open the vacuum port, and vacuum for 10-12 hours. Then, turn off the temperature control switch, pump inert gas from the vacuum port, and after the temperature drops to room temperature, remove the collection bottle to obtain a highly purified solid activator.

[0035] The present invention also provides an application of the solid activator purified by the above activator purification method in preparing a cesium iodide scintillation screen.

[0036] Beneficial effects

[0037] The present invention purifies the activator by heating and dissolving the waste raw material containing the activator and cesium iodide produced after cesium iodide evaporation, screening and filtering, washing with pure water, melting and evaporating, and condensing and collecting. The entire purification process is environmentally friendly and safe, and does not generate secondary pollution. After heating and filtering to remove impurities, the activator filter cake has a purity of up to 95%. After washing the activator filter cake with pure water, the purity of the activator can reach 99%. After heating and melting the dried solid activator, the activator collected by condensation has a purity of up to 99.99%.

[0038] The purification method and equipment of the present invention are simple to operate, safe and efficient, and can achieve sustainable and continuous production. The purified activator can be directly applied to the production of activator single crystals and the preparation of cesium iodide scintillating screens.

[0039] In addition, since the present invention simplifies the separation and purification equipment, the requirements for the environment and high specifications of the equipment are reduced, thereby reducing the cost of batch production. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the overall structure of the heating separation device;

[0041] Figure 2 Schematic diagram of the tank structure;

[0042] Figure 3 It is a cross-sectional view of the heating separation device;

[0043] Figure 4 is a cross-sectional view of the filter device;

[0044] Figure 5 It is a schematic diagram of the overall structure of the heating and melting equipment;

[0045] Figure 6 Schematic diagram of boiler structure.

[0046] In the figure: 1. Heating and separating device; 11. Bracket; 111. Mounting platform; 12. Tank body; 121. Through-port; 122. Vacuum pump port; 123. Water inlet; 124. Sensor insertion port; 13. Agitator; 131. Agitator shaft; 132. Agitator head; 14. Filtering device; 141. Piston; 142. Filtering assembly; 1421. Screen; 1411. Piston body; 1412. Piston cavity; 15. Support telescopic tube; 2. Heating and melting equipment; 21. Boiler; 211. Feed port; 22. Operation box; 23. Support frame; 231. Support platform; 232. Support column; 24. Collecting bottle; 241. Vacuum port. DETAILED DESCRIPTION

[0047] The present invention is further illustrated by the following examples, which are intended to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the present invention.

[0048] Example 1

[0049] like Figure 1 and Figure 5 The illustrated activator purification system for cesium iodide scintillator screens can be used to purify, recycle, and reuse cesium iodide crystals and waste materials generated after vapor deposition. The activator purification system consists of a heating and separation device 1 and a heating and melting device 2. The heating and separation device 1 primarily removes cesium iodide, as well as impurities such as furnace wall dust, metal particles, and glass particles, from the waste material to obtain a solid activator. The heating and melting device 2 melts and evaporates the separated solid activator, further removing any remaining impurities to obtain a high-purity activator. Purifying and recycling the activator material allows for recycling, saving resources and reducing costs while increasing efficiency. Furthermore, the purified activator is fully compatible with use in high-performance cesium iodide scintillator screens.

[0050] like Figures 1 to 5 The activator purification system shown in the figure includes a heating separation device 1 for separating the activator filter cake and a heating melting device 2 for further purifying the solid activator; the heating separation device 1 includes a bracket 11, a tank body 12, an agitator 13, a filtering device 14, and a supporting telescopic tube 15; the tank body 12 is fixedly mounted on the bracket 11; the tank body 12 is provided with a feeding port and an open bottom; the top of the tank body 12 is provided with a through-port 121; the agitator 13 includes a stirring shaft 131 and a stirring head 132; the stirring shaft 131 passes through the through-port 121 into the interior of the tank body 12 and is sealed with the through-port 121; the filtering device 14 It includes a piston 141 and a filter assembly 142; the piston 141 includes a piston body 1411 and a piston cavity 1412 located in the piston body 1411; the piston 141 is movably installed in the tank body 12, and the piston 141 is sealed to the inner wall of the tank body 12; the top of the piston body 1411 is open, and a drain valve is provided at the bottom; the filter assembly 142 is arranged in the piston cavity 1412; the filter assembly 142 contains a three-stage screen 1421 and a layer of filter cloth 1422; the support telescopic tube 15 is fixedly connected to the bottom of the piston body 1411; the support telescopic tube 15 is fixedly connected to the bracket 11.

[0051] Waste material containing an activator and cesium iodide is placed into the tank 12. After adjusting the reaction conditions, it is stirred and heated until the cesium iodide in the waste material is completely dissolved in pure water, while the activator remains in a granular precipitated state. The cesium iodide aqueous solution is discharged through the filter device 14. Most impurities such as dust, metal particles, and glass particles are intercepted by the upper screen, while the activator is intercepted by the filter cloth. The activator filter cake after screening and filtration is thoroughly washed to remove residual cesium iodide salts. After drying, a solid activator is obtained. The support telescopic tube 15 is controlled to be compressed, driving the piston 141 to be withdrawn from the bottom of the tank 12 to facilitate the removal of the solid activator.

[0052] The tank body 12 is a jacketed heating tank body, which adopts oil bath heating and thermal insulation design, and the thermal insulation is not lower than 100°C. The tank body 12 is made of titanium alloy and has a negative pressure resistance of not lower than -0.1Mpa and a high pressure resistance of not lower than 1Mpa.

[0053] The jacketed heated tank uses an agitator 13 to thoroughly mix the reactants, increasing the reaction rate and accelerating the process. Oil is also used as a medium to control the temperature of the reaction system, providing a stable heat source while ensuring the reaction is precisely controlled within the set temperature range, resulting in high safety. Titanium alloy offers advantages such as high temperature resistance and strong corrosion resistance. The tank structure can withstand performance changes at different pressures, ensuring its safety and effectiveness.

[0054] like Figure 2As shown, the top of the tank body 12 is further provided with an air pump port 122 , a water inlet 123 and a sensor insertion port 124 .

[0055] The gas in the tank body 12 is effectively removed through the vacuum pump port 122 to avoid the influence of the gas. The water inlet 123 is provided to facilitate direct washing of the filter cake. The sensor insertion port 124 is provided to measure the pressure and temperature in the tank, which can accurately monitor the changes in the pressure and temperature in the tank and improve the safety of the equipment.

[0056] like Figure 3 As shown, the stirring shaft 131 and the stirring head 132 are detachably connected, the stirring head 132 is a paddle-type stirring blade, and the stirrer 13 is made of titanium alloy.

[0057] The stirring shaft 131 and the stirring head 132 are detachably connected for easy cleaning. The stirring head 132 uses a paddle-type stirring blade, which can effectively mix liquid and solid substances evenly, and has a small footprint and is easy to maintain. The titanium alloy material has the advantages of high temperature resistance and strong corrosion resistance.

[0058] like Figure 3 and Figure 4 As shown, the mesh size of the screen 1421 is 30-325 mesh and is made of titanium alloy; the mesh size of the filter cloth 1422 is not less than 1.5 mesh and is made of PTFE high-temperature resistant plastic. The filter cloth 1422 is set on a layer of screen 1421 near the bottom of the piston body 1411.

[0059] The mesh size of the upper screen of filter assembly 142 ensures effective retention of impurities such as furnace wall dust, metal particles, and glass particles, while preventing the activator from being retained. The pore size of the filter cloth layer is designed to effectively retain the activator, achieving separation. The filter cloth is placed on the bottom screen layer to provide support for the filter cloth.

[0060] like Figure 1 As shown, a lifting mechanism is fixedly installed on the side of the bracket 11, and the lifting mechanism is fixedly connected to the stirrer 13.

[0061] The lifting mechanism allows the stirrer 13 to flexibly adjust the height and position of the stirring head 132 according to different stirring requirements to improve stirring efficiency. A pulley is provided at the bottom of the bracket 11 to facilitate the movement of the equipment.

[0062] Mounting platforms 111 are provided in the middle and below the bracket 11 , and the mounting platform 111 in the middle is used to fix the tank body 12 ; the mounting platform 111 below is used to fix and support the telescopic tube 15 ; a pulley is provided at the bottom of the bracket 11 .

[0063] The tank body 12 and the supporting telescopic tube 15 are installed on the mounting platform 111 to ensure the stability of the entire equipment. A pulley is provided at the bottom of the bracket 11 to facilitate the movement of the equipment.

[0064] like Figure 5 、 Figure 6 As shown, the heating and melting equipment 2 includes a boiler 21, an operating box 22, and a support frame 23. The boiler 21 is at least partially arc-shaped. A quartz glass pipe is installed in the boiler 21. The quartz glass pipe is open at both ends, one end is a feed inlet 211, and the other end is open downward and connected to the collection bottle 24. The quartz glass pipe passes through three adjustable temperature zones, including a high temperature zone, a medium temperature zone, and a low temperature zone. The high temperature zone is 850-950°C, the medium temperature zone is 600-850°C, and the low temperature zone is 450-600°C.

[0065] The support frame 23 is fixed with the operation box 22 and the collection bottle 24 .

[0066] At least part of the boiler 21 is curved. The curved pipe redirects the internal gas flow, reduces stress on the pipe, and increases its service life. The end of the quartz glass pipe connected to the collection flask 24 is open downward, facilitating material collection. The solid activator is placed in the heating and melting apparatus 2 and passes through three different temperature zones. The different boiling points of the substances facilitate vaporization and impurity removal. Simultaneously, in the low-temperature zone, the gaseous activator transforms into a liquid activator, which flows through the quartz glass pipe opening into the collection flask 24, resulting in a high-purity activator that can be reused in the preparation of cesium iodide scintillator screens.

[0067] The collecting bottle 24 is provided with an air extraction port 241 .

[0068] The excess gas in the device is effectively removed through the gas extraction port 241 to avoid the influence of the gas.

[0069] like Figure 1 As shown, the support frame 23 includes a support platform 231 and a support column 232 ; the operation box 22 is set on the support platform 231 ; the collection bottle 24 is set on the support column 232 ; and a pulley 233 is provided at the bottom of the support frame 23 .

[0070] The operating box 22 and the collecting bottle 24 are respectively mounted on the supporting platform 231 and the supporting column 232 to ensure the stability of the entire device. The supporting frame 23 is provided with a pulley 233 to facilitate the movement of the device.

[0071] Example 2

[0072] Based on Example 1, the present invention also provides a method for purifying an activator, comprising the following steps:

[0073] Step (1): placing the waste material containing the activator and cesium iodide in a closed container, adding pure water, stirring and heating to dissolve under a vacuum state, and stopping stirring when the cesium iodide is completely dissolved in the pure water to obtain a mixed slurry containing the activator and cesium iodide;

[0074] Step (2): subjecting the mixed slurry containing the activator and cesium iodide obtained in step (1) to multi-stage screening and filtering, and separating the activator filter cake at the bottom layer;

[0075] Step (3): washing and drying the activator filter cake obtained in step (2) to obtain a solid activator;

[0076] Step (4): The solid activator obtained in step (3) is subjected to multi-stage melting heating to convert the solid activator into a gaseous activator first and then into a liquid activator, and then cooled to obtain a highly pure activator solid.

[0077] Example 3

[0078] A method for purifying an activator using the activator purification system of Example 1 specifically comprises the following steps:

[0079] S1. 5 kg of cesium iodide and activator raw materials (the activator accounts for 90%) are added into the tank body 12 from the feeding port, 30 L of pure water is added, and vacuum work is first performed from the vacuum pump port 122 on the top of the tank body 12. The stirring device 13 is started and the temperature is raised to 110° C. in an oil bath to heat the waste raw materials for 2 hours to completely dissolve the cesium iodide in the pure water. The stirring is stopped to obtain a mixed slurry containing the activator and cesium iodide;

[0080] S2. The mixed slurry containing the activator and cesium iodide is subjected to multi-stage screening and filtration through the filter device 14. The mesh sizes of the three-stage screens are 30 mesh, 100 mesh, and 325 mesh from top to bottom, and the mesh size of the filter cloth is 10,000 mesh. The cesium iodide aqueous solution passes through the screens and filter cloth and is discharged through the drain valve at the bottom of the piston body 1411. The activator is retained on the filter cloth.

[0081] S3. Pump pure water into the water inlet 123 at the top of the tank body 12 to wash the activator until the conductivity of the washed water is less than 10 μs / cm;

[0082] S4, pumping nitrogen from the vacuum pump port 122 at the top of the tank body 12 to pressurize and dehydrate the activator for 1 hour to obtain a solid activator;

[0083] S5. Transfer the solid activator obtained in S4 to the feed port 211 of the heating and melting equipment 2, set the temperature of the high temperature zone to 120°C, the temperature of the medium temperature zone to 110°C, and the temperature of the low temperature zone to 100°C, heat for 2 hours, open the exhaust port 241, and exhaust for 10 hours. Set the temperature of the high temperature zone to 880°C, the temperature of the medium temperature zone to 800°C, and the temperature of the low temperature zone to 550°C again, heat for 8 hours, open the exhaust port 241, and exhaust for 10 hours. Then, turn off the temperature control switch, pump nitrogen from the exhaust port 241, and after the temperature drops to room temperature, remove the collecting bottle 24 to obtain a highly purified solid activator.

[0084] The amount of activator collected in this embodiment is 4.32 kg, and the yield is 96%.

[0085] Example 4

[0086] A method for purifying an activator using the activator purification system for a cesium iodide scintillating screen of Example 1 specifically comprises the following steps:

[0087] S1. 5.2 kg of cesium iodide and activator raw materials (the activator accounts for 90%) are added into the tank body 12 from the feeding port, 52 L of pure water is added, and vacuum work is first performed from the vacuum pump port 122 on the top of the tank body 12. The stirring device 13 is started and the temperature is raised to 140° C. in an oil bath to heat the waste raw materials for 3.5 hours to completely dissolve the cesium iodide in the pure water. The stirring is stopped to obtain a mixed slurry containing the activator and cesium iodide;

[0088] S2. The mixed slurry containing the activator and cesium iodide is subjected to multi-stage screening and filtration through the filter device 14. The mesh sizes of the three-stage screens are 30 mesh, 100 mesh, and 325 mesh from top to bottom, and the mesh size of the filter cloth is 10,000 mesh. The cesium iodide aqueous solution passes through the screen and filter cloth of the screen assembly 141 and is discharged through the drain valve at the bottom of the piston body 1411. The activator is retained on the filter cloth.

[0089] S3. Pump pure water into the water inlet 123 at the top of the tank 12 to wash the activator until the conductivity of the washed water is less than 10 μs / cm.

[0090] S4, pumping nitrogen from the vacuum pump port 122 at the top of the tank body 12 to pressurize and dehydrate the activator for 3 hours to obtain a solid activator;

[0091] S5. Transfer the solid activator obtained in S4 to the feed port 211 of the heating and melting equipment 2, set the temperature of the high temperature zone to 140°C, the temperature of the medium temperature zone to 120°C, and the temperature of the low temperature zone to 110°C, heat for 3 hours, open the exhaust port 241, and exhaust for 12 hours. Set the temperature of the high temperature zone to 900°C, the temperature of the medium temperature zone to 850°C, and the temperature of the low temperature zone to 580°C again, heat for 12 hours, open the exhaust port 241, and after exhausting for 12 hours, turn off the temperature control switch, pump nitrogen from the exhaust port 241, and after the temperature drops to room temperature, remove the collecting bottle 24 to obtain a highly purified solid activator.

[0092] The amount of activator collected in this embodiment is 4.5 kg, and the yield is 96.15%.

[0093] Activator ICP test experiment

[0094] In order to verify the effectiveness of the above purification method, inductively coupled plasma testing (ICP testing) was performed on the concentrations of common impurities contained in the activator raw materials before and after purification in Example 3 and Example 4.

[0095] Table 1 is a table showing the concentrations of common impurities in the activators before and after purification in Examples 3 and 4 of the present invention.

[0096] As shown in Table 1, the impurity concentration of the purified activator is significantly reduced, and the purity of the activator reaches 99.99%. It can be used as a luminescent agent in the manufacture of cesium iodide scintillator, thereby improving the stability of the scintillator and optimizing the performance of the scintillator.

[0097] Table 1: Common impurity concentrations of activators before and after purification

[0098]

[0099] The purified activator was used in the cesium iodide scintillation screen fabrication experiment

[0100] A uniform cesium iodide thin film scintillating screen was formed on a substrate by vacuum coating using the activator purified in Example 4 of the present invention at a ratio of cesium iodide to activator of 1000:2.

[0101] Table 2 shows the performance test results of the cesium iodide scintillator produced using the purified activator in Example 4 of the present invention.

[0102] As shown in Table 2, the sensitivity of the prepared cesium iodide scintillator screen exceeds 600, which meets the requirement between 600 and 800. The MTF value spatial resolution of the scintillator screen exceeds the limit requirements under different X-ray metrology tests.

[0103] Table 2: Cesium iodide scintillation screen performance test report

[0104]

[0105]

[0106] In summary, the activator obtained by the activator purification system and purification method for cesium iodide scintillating screen provided by the present invention can be directly applied to the preparation of cesium iodide scintillating screen, and the high-performance cesium iodide scintillating screen prepared can meet application requirements.

[0107] The above embodiments are illustrative only and are intended to illustrate the technical concepts and features of the present invention so that those skilled in the art can understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A system for purifying an activator for a cesium iodide scintillator screen, characterized in that: The invention comprises a heating separation device (1) for separating an activator filter cake from a raw material containing an activator, and a heating melting device (2) for evaporating and purifying the activator filter cake; the heating separation device (1) comprises a bracket (11), a tank body (12), a stirrer (13), a filtering device (14), and a supporting telescopic tube (15); the tank body (12) is fixedly mounted on the bracket (11); the tank body (12) is provided with a feeding port and an open bottom; the top of the tank body (12) is provided with a through-hole (121); the stirrer (13) comprises a stirring shaft (131) and a stirring head (132); the stirring shaft (131) passes through the through-hole (121) and enters the interior of the tank body (12), and is sealed with the through-hole (121); the filtering device (14 ) includes a piston (141) and a filter assembly (142); the piston (141) includes a piston body (1411) and a piston cavity (1412) located in the piston body (1411); the piston (141) is movably installed in the tank body (12), and the piston (141) is sealed to the inner wall of the tank body (12); the top of the piston body (1411) is open, and the bottom is provided with a drain valve; the filter assembly (142) is arranged in the piston cavity (1412); the filter assembly (142) contains at least three levels of screens (1421) and a layer of filter cloth; the supporting telescopic tube (15) is fixedly connected to the bottom of the piston body (1411); the supporting telescopic tube (15) is fixedly connected to the bracket (11).

2. The activator purification system according to claim 1, characterized in that: The tank body (12) is a jacketed heating tank body, which is heated by an oil bath, and the tank body (12) is made of an alloy material; the top of the tank body (12) is also provided with an air pump port (122), a water inlet (123) and a sensor insertion port (124); the stirring shaft (131) and the stirring head (132) are detachably connected, and the stirring head (132) is a paddle-type stirring blade.

3. The activator purification system according to claim 2, characterized in that: The mesh number of the screen (1421) is 30-325 meshes and is made of alloy material; the mesh number of the filter cloth is not less than 1.5 meshes and is made of high-temperature resistant plastic material; the filter cloth is arranged on a layer of screen (1421) close to the bottom of the piston body (1411).

4. The activator purification system according to claim 1, characterized in that: A lifting mechanism is fixedly installed on the side of the bracket (11), and the lifting mechanism is fixedly connected to the stirrer (13); a mounting platform (111) is provided in the middle and below of the bracket (11), and the mounting platform (111) in the middle is fixedly installed on the tank body (12); the mounting platform (111) below is fixedly installed on the supporting telescopic tube (15); and a pulley is provided at the bottom of the bracket (11).

5. The activator purification system according to claim 3, characterized in that: The heating and melting equipment (2) comprises a boiler (21), an operating box (22) and a support frame (23), wherein at least a portion of the boiler (21) is arc-shaped; a quartz glass pipe is provided in the boiler (21); both ends of the quartz glass pipe are open, one end is a feed port (211), and the other end is open downward and connected to a collecting bottle (24); the quartz glass pipe passes through at least three adjustable temperature zones; and the support frame (23) is fixedly mounted with the operating box (22) and the collecting bottle (24).

6. The activator purification system according to claim 5, characterized in that: The collecting bottle (24) is provided with an air extraction port (241).

7. The activator purification system according to claim 5, characterized in that: The support frame (23) comprises a support platform (231) and a support column (232); the operation box (22) is arranged on the support platform (231); the collection bottle (24) is arranged on the support column (232); and a pulley (233) is provided at the bottom of the support frame (23).

8. The method for purifying an activator for a cesium iodide scintillator screen according to any one of claims 1 to 7, characterized in that: The steps include: Step (1): placing the waste raw material of cesium iodide containing the activator in a closed container, adding pure water, stirring and heating to dissolve under vacuum, and stopping stirring after the cesium iodide is completely dissolved in the pure water to obtain a mixed slurry containing the activator and cesium iodide; Step (2): subjecting the mixed slurry containing the activator and cesium iodide obtained in step (1) to multi-stage screening and filtering, and separating the activator filter cake at the bottom layer; Step (3): washing and drying the activator filter cake obtained in step (2) to obtain a solid activator; Step (4): The solid activator obtained in step (3) is subjected to multi-stage melting heating to convert the solid activator into a gaseous activator first and then into a liquid activator. After cooling to room temperature, a highly pure activator solid is obtained.

9. The activator purification method according to claim 8, characterized in that: The steps include: S1. Add the cesium iodide waste material containing the activator into the tank body (12) from the feeding port, add pure water at a material-liquid ratio of 1:6-10, first perform vacuuming from the vacuum pump port (122) at the top of the tank body (12), start the stirring device (13), raise the temperature to 110-140°C in an oil bath, heat the waste material for 2-3 hours, and completely dissolve the cesium iodide in the pure water. Stop stirring to obtain a mixed slurry containing the activator and cesium iodide; S2, the mixed slurry containing the activator and cesium iodide is subjected to multi-stage screening and filtration through the filter device (14), the cesium iodide aqueous solution passes through the screen (1421) and the filter cloth, and is discharged through the drain valve at the bottom of the piston body (1411), and the activator is retained on the filter cloth; S3, pumping pure water from the water inlet (123) at the top of the tank (12) to wash the activator until the conductivity of the washed water is less than 10 us / cm; S4, pumping inert gas from the vacuum pump port (122) at the top of the tank (12) to pressurize and dehydrate the activator to obtain a solid activator; S5. The solid activator obtained in S4 is transferred to the feed port (211) of the heating and melting device (2), the temperature is set, and heating is carried out for 2-3 hours. The exhaust port (241) is opened and the exhaust is carried out for 10-12 hours. The heating temperature is set again, and heating is carried out for 8-12 hours. The exhaust port (241) is opened and the exhaust is carried out for 10-12 hours. The temperature control switch is turned off, and an inert gas is pumped into the exhaust port (241). After the temperature drops to room temperature, the collecting bottle (24) is removed to obtain a highly purified solid activator.

10. A method for purifying an activator for a cesium iodide scintillating screen according to claim 8 or 9, to obtain a high-purity activator for use as a luminescent dopant for cesium iodide crystals and scintillating screens.

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