Activator purification system for cesium iodide scintillation screen, purification method and application

Abstract

The invention belongs to the technical field of purification of activators for cesium iodide scintillation screens, and particularly relates to a purification system and purification method for an activator for a cesium iodide scintillation screen and application. The activating agent purification system provided by the invention comprises a heating and separating device for separating an activating agent for a solid cesium iodide scintillation screen and heating and melting equipment for further purifying the solid activating agent, and the heating and separating device is mainly used for removing cesium iodide in waste and impurities such as furnace wall dust, metal particles and glass particles. The heating melting equipment is used for melting and evaporating the separated activating agent, residual impurities are removed again, and the high-purity activating agent is obtained. In addition, the invention further provides an activating agent purification method, the aim of purifying the activating agent is achieved through heating dissolution, screening filtration, pure water washing, melting evaporation and condensation collection, the whole purification process is environmentally friendly and safe, secondary pollution is not generated, the purified activating agent can be directly applied to production of cesium iodide single crystals, and the method is suitable for industrial production. And preparing the cesium iodide scintillation screen.

Description

Technical Field

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

[0002] The activator for cesium iodide scintillator is an inorganic halide. When manufacturing cesium iodide scintillator, in order to improve the stability of the scintillator and optimize the performance of the scintillator, the activator is added to the cesium iodide raw material, and then mixed and prepared by thermal evaporation process.

[0003] In the above process, solid waste containing a large amount of activators will be generated after evaporation. The types of activators for cesium iodide thin film scintillator screens contain halides of thallium, bismuth, ytterbium and other ions, which are all very toxic and harmful elements. Among them, thallium and its compounds are mutagenic, teratogenic and carcinogenic to organisms. Thallium poisoning can cause dizziness, fatigue, vomiting and other symptoms in the human body, and even cause epilepsy and blindness in severe cases. Therefore, it is necessary to recycle solid waste containing thallium.

[0004] The common treatment method is to separate soluble thallium ions through extraction, adsorption and other processes. However, the organic matter extraction process is long and complicated to handle, and the thallium ion stripping process is difficult and inefficient. During the process, a large amount of organic wastewater will be generated, which can easily cause secondary wastewater treatment problems. At present, most manufacturers prefer specific resins to selectively adsorb thallium. This adsorption process is difficult to operate, and the thallium-containing resin after adsorption also needs to be treated as hazardous waste, which also causes secondary pollution. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides an activator purification system, a purification method and an application for a cesium iodide scintillator screen, the purpose of which is to filter and recover an activator filter cake from waste materials in an environmentally friendly manner, and then undergo a melting purification step to obtain an activator material with high purity, which can be used for the production of cesium iodide crystal activator single crystals, and the purified activator material is fully suitable for the use of high-performance cesium iodide scintillator screens, thereby achieving the effects of material recycling, resource saving, cost reduction and efficiency improvement.

[0006] The invention provides an activator purification system for cesium iodide scintillation screen, comprising a heating separation device for separating an activator filter cake from a raw material containing an activator and a heating melting device for evaporating and purifying the activator filter cake; the heating separation device comprises a bracket, a tank body, a stirrer, a filtering device, and a supporting telescopic tube; the tank body is fixedly installed on the bracket; the tank body is provided with a feeding port and an open bottom; a through-port is provided on the top of the tank body; the stirrer comprises a stirring shaft and a stirring head; the stirring shaft passes through the through-port into the interior of the tank body and is sealed with the through-port; 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 installed in the tank body, and the piston is sealedly connected 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 port; 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; the telescopic supporting tube is fixedly connected to the bracket.

[0007] The above activator purification system can be used for cesium iodide crystals and waste generated after evaporation to purify, recycle and reuse the activator. The activator purification system consists of two parts: a heating separation device and a heating melting device. The heating separation device is mainly used to remove cesium iodide and impurities such as furnace wall dust, metal particles, and glass particles in the waste. The heating melting device melts and evaporates the separated activator, removes residual impurities again, and obtains a high-purity activator. The waste raw material is put into the tank body, and after adjusting the reaction conditions, it is stirred and heated so that the cesium iodide in the waste is completely dissolved in pure water. The activator still maintains a particle precipitation state. The cesium iodide aqueous solution is discharged through the filtering device, and most of the dust, metal particles, glass particles and other impurities are intercepted by the screen, while the activator is intercepted by the filter cloth. The activator filter cake after screening and filtration is fully washed to remove the residual cesium iodide salt, and a solid activator is obtained after drying. The compression of the support telescopic tube is controlled to drive the piston to be withdrawn from the bottom of the tank body, which is convenient for taking out 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; 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; the agitator shaft and the agitator head are detachably connected, and the agitator head is a paddle-type agitator blade.

[0009] The jacketed heating tank can fully mix the reactants through the agitator to increase the reaction rate and speed up the process. At the same time, the temperature of the reaction system is controlled by oil as a medium, which not only provides a stable heat source, but also ensures that the reaction is accurately controlled within the set temperature range, and is highly safe. 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 the material is alloy; the mesh number of the filter cloth is greater than 10,000 meshes, and the material is high-temperature resistant plastic; 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 effective interception of impurities such as furnace wall dust, metal particles, glass particles, etc., but cannot intercept the activator. The aperture 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 play a supporting role for 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 below the bracket, and the mounting platform in the middle position is fixedly installed on the tank body; the mounting platform below 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 to improve 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. A pulley is 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 arranged 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 collecting 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 collecting bottle.

[0019] At least part of the boiler is arc-shaped. The curved pipe can change the flow direction of the internal gas, reduce the stress on the pipe, and increase the service life. The end of the quartz glass pipe connected to the collection bottle is open downward to facilitate the collection of materials. The solid activator is placed in the heating and melting equipment and passes through three different temperature zones. With the help of different boiling points of the substances, it can be better vaporized and removed. At the same time, the gaseous activator is converted into a liquid activator and flows into the collection bottle through the quartz glass tube mouth to obtain a high-purity activator, which can be used again in the preparation process of the cesium iodide scintillation screen with the participation of the activator.

[0020] Furthermore, the collecting bottle is provided with a gas 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 collecting bottle is arranged on the support column; and a pulley is arranged at the bottom of the support frame.

[0023] The operating box and the collecting bottle are respectively installed on the supporting platform and the supporting column to ensure the stability of the whole equipment. The supporting frame is provided 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 vacuum, 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. Put the waste raw material containing activator and cesium iodide into the tank body from the feeding port, add pure water at a material-liquid ratio of 1:6-10, first perform vacuum work from the vacuum pump port on the top of the tank body, start the stirring device, raise the temperature to 110-140° C. through an oil bath, heat the waste raw material for 2-3 hours, completely dissolve cesium iodide in pure water, stop stirring, and obtain a mixed slurry containing 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 filtering device, the cesium iodide aqueous solution passes through the screen and filter cloth of the filtering assembly, and is discharged through the drain valve port at the bottom of the piston body, and the activator is retained on the filter cloth;

[0032] S3. Pump pure water from 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 collecting 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 to prepare a cesium iodide scintillation screen.

[0036] Beneficial Effects

[0037] The present invention achieves the purpose of purifying the activator by heating and dissolving, screening and filtering, washing with pure water, melting and evaporating, and condensing and collecting the waste raw materials containing the activator and cesium iodide generated after cesium iodide evaporation. The entire purification process is environmentally friendly and safe, and does not generate secondary pollution. After heating, filtering and impurity removal, the purity of the activator filter cake can reach 95%, and after the activator filter cake is washed with pure water, the purity of the activator can reach 99%, and after the dried solid activator is heated and melted, the purity of the activator collected by condensation reaches 99.99%.

[0038] The purification method and equipment of the present invention are simple to operate, safe and efficient, and can realize sustainable and continuous production. The purified activator can be directly applied to the production of activator single crystals and the preparation of cesium iodide scintillator 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 batch production cost. 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 It is a schematic diagram of the tank structure;

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

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

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

[0045] Figure 6 This is a schematic diagram of the boiler structure.

[0046] In the figure: 1. heating and separation device; 11. bracket; 111. mounting table; 12. tank body; 121. penetration 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 chamber; 15. supporting telescopic tube; 2. heating and melting equipment; 21. boiler; 211. feed port; 22. operating box; 23. supporting frame; 231. supporting table; 232. supporting 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 solution of the present invention and should not be construed as a limitation.

[0048] Example 1

[0049] like Figure 1 and Figure 5 The activator purification system for cesium iodide scintillator screen shown can be used for cesium iodide crystals and waste materials generated after evaporation to purify and recycle the activator. The activator purification system consists of a heating separation device 1 and a heating melting device 2. The heating separation device 1 is mainly used to remove cesium iodide and impurities such as furnace wall dust, metal particles, and glass particles from the waste to separate the solid activator. The heating melting device 2 melts and evaporates the separated solid activator to remove residual impurities again to obtain a high-purity activator. By purifying and recycling the activator material, recycling is achieved, which not only saves resources and achieves the effect of reducing costs and increasing efficiency, but also the purified activator can be fully used again for the use of high-performance cesium iodide scintillator screens.

[0050] like Figures 1 to 5 The activator purification system shown in the figure comprises 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 comprises 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 comprises 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 and connected to the inner wall of the tank body 12; the top of the piston body 1411 is open, and a drainage 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] The waste material containing the activator and cesium iodide is put into the tank body 12, and after adjusting the reaction conditions, it is stirred and heated so that the cesium iodide in the waste is completely dissolved in the pure water, and the activator still maintains a particle precipitation state. The cesium iodide aqueous solution is discharged through the filter device 14, and most of the dust, metal particles, glass particles and other impurities are intercepted by the upper screen, while the activator is intercepted by the filter cloth. The filter cake of the activator after screening and filtration is fully washed to remove the residual cesium iodide salt, and a solid activator is obtained after drying. The support telescopic tube 15 is controlled to be compressed to drive the piston 141 to be withdrawn from the bottom of the tank body 12, so as to facilitate the removal of the solid activator.

[0052] The tank body 12 is a jacketed heating tank body, which is heated by an oil bath and has a heat preservation design, and the heat preservation temperature is not less than 100°C. The tank body 12 is made of titanium alloy, and has a negative pressure resistance of not less than -0.1Mpa and a high pressure resistance of not less than 1Mpa.

[0053] The jacketed heating tank can fully mix the reactants through the agitator 13, increase the reaction rate, and speed up the process. At the same time, the temperature of the reaction system is controlled by oil as a medium, which provides a stable heat source and ensures that the reaction is accurately controlled within the set temperature range, and the safety is also high. Titanium alloy material has the advantages of high temperature resistance and strong corrosion resistance. The tank structure can withstand performance changes at different pressures, which also ensures the safety and effectiveness of the tank.

[0054] like Figure 2As shown, 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 .

[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 number of the screen 1421 is 30-325 meshes, and it is made of titanium alloy; the mesh number of the filter cloth 1422 is not less than 1.5 meshes, and it is made of PTFE high temperature resistant plastic material. The filter cloth 1422 is arranged on a layer of screen 1421 near the bottom of the piston body 1411.

[0059] The mesh size of the upper screen of the filter assembly 142 can ensure effective interception of impurities such as furnace wall dust, metal particles, glass particles, etc., but cannot intercept the activator. The aperture design of the filter cloth layer can effectively intercept the activator to achieve the purpose of separation. The filter cloth is set on the bottom screen and can support 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 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 device. A pulley is provided at the bottom of the bracket 11 to facilitate the movement of the device.

[0064] like Figure 5 , Figure 6 As shown, the heating and melting equipment 2 includes a boiler 21, an operation box 22 and a support frame 23, and at least part of the boiler 21 is arc-shaped; a quartz glass pipe is arranged 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 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 used to fix the operation box 22 and the collection bottle 24 .

[0066] At least part of the boiler 21 is arc-shaped. The curved pipe can change the flow direction of the internal gas, reduce the stress on the pipe, and increase the service life. The end of the quartz glass pipe connected to the collecting bottle 24 is open downward to facilitate the collection of materials. The solid activator is placed in the heating and melting device 2 and passes through three different temperature zones. With the help of different boiling points of the substances, it can be better vaporized and removed. At the same time, in the low temperature zone, the gaseous activator becomes a liquid activator and flows into the collecting bottle 24 through the quartz glass pipe mouth to obtain a high-purity activator, which can be used again in the preparation process of the cesium iodide scintillation screen with the participation of the activator.

[0067] The collecting bottle 24 is provided with a gas extraction port 241 .

[0068] The excess gas in the device can be 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 arranged on the support platform 231 ; the collection bottle 24 is arranged on the support column 232 ; and a pulley 233 is arranged 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 vacuum, 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 put into the tank body 12 from the feeding port, 30 L of pure water is added, and vacuuming is first performed from the vacuum pump port 122 at the top of the tank body 12, and the stirring device 13 is started. The temperature is raised to 110° C. through an oil bath, and the waste raw materials are heated 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 filtering device 14, wherein the mesh numbers of the three-stage screens are 30 mesh, 100 mesh and 325 mesh from top to bottom, and the mesh number of the filter cloth is 10000 mesh. The cesium iodide aqueous solution passes through the screen and the filter cloth and is discharged through the drain valve port at the bottom of the piston body 1411, and the activator is retained on the filter cloth;

[0081] S3, pumping pure water from 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 10us / 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 after exhausting for 10 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.

[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 scintillator 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 put into the tank body 12 from the feeding port, 52 L of pure water is added, and vacuuming is first performed from the vacuum pump port 122 at the top of the tank body 12, and the stirring device 13 is started. The temperature is raised to 140° C. through an oil bath, and the waste raw materials are heated 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 filtering device 14, wherein the mesh numbers of the three-stage screens are 30 mesh, 100 mesh and 325 mesh from top to bottom, and the mesh number of the filter cloth is 10000 mesh. The cesium iodide aqueous solution passes through the screen and filter cloth of the set screen assembly 141 and is discharged through the drain valve port at the bottom of the piston body 1411, and the activator is retained on the filter cloth;

[0089] S3, pumping pure water from 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 10us / 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, then 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 effect of the above purification method, the concentration of common impurities contained in the activator raw materials before and after purification in Example 3 and Example 4 was tested by inductively coupled plasma (ICP test).

[0095] Table 1 is a table showing the concentration of common impurities contained 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 screens to improve the stability of the scintillator screens and optimize the performance of the scintillator screens.

[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 production experiment

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

[0101] Table 2 is a table showing the performance measurement results of the cesium iodide scintillator screen made from 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 of 600-800. 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 scintillator screen provided by the present invention can be directly applied to the preparation of cesium iodide scintillator screen, and the prepared high-performance cesium iodide scintillator screen can meet application requirements.

[0107] The above embodiments are exemplary, and their purpose is to illustrate the technical concept and features of the present invention so that people familiar with the technology in this field can understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope 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 support (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 support (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 stirrer (13) comprises a stirring shaft (131) and a stirring head (132); the stirring shaft (131) passes through the through-port (121) and enters the interior of the tank body (12), and is sealed with the through-port (121); the filtering device (14 ) comprises a piston (141) and a filter assembly (142); the piston (141) comprises 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 sealedly connected 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 mounted on the side of the bracket (11), and the lifting mechanism is fixedly connected to the stirrer (13); mounting platforms (111) are provided in the middle and below the bracket (11), and the mounting platform (111) in the middle is fixedly mounted on the tank body (12); the mounting platform (111) at the bottom is fixedly mounted 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 device (2) comprises a boiler (21), an operating box (22) and a support frame (23); at least part of the boiler (21) is arc-shaped; a quartz glass pipe is arranged inside the boiler (21); both ends of the quartz glass pipe are open, one end is a feed inlet (211), and the other end is open downward and connected to a collection bottle (24); the quartz glass pipe passes through at least three adjustable temperature zones; the support frame (23) is fixedly mounted with the operating box (22) and the collection bottle (24).

6. The activator purification system according to claim 5, characterized in that: The collecting bottle (24) is provided with a gas 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 when 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 6, characterized in that: The steps include: S1. Feeding the cesium iodide waste material containing the activator into the tank body (12) from the feeding port, adding pure water at a material-liquid ratio of 1:6-10, first performing vacuuming from the vacuum pump port (122) at the top of the tank body (12), starting the stirring device (13), heating the waste material to 110-140° C. in an oil bath for 2-3 hours, so that the cesium iodide is completely dissolved in the pure water, stopping stirring, and obtaining 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 filtering through the filtering 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 body (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, heating is performed for 2-3 hours, the exhaust port (241) is opened, exhaust is performed for 10-12 hours, the heating temperature is set again, heating is performed for 8-12 hours, the exhaust port (241) is opened, exhaust is performed for 10-12 hours, the temperature control switch is turned off, an inert gas is pumped into the exhaust port (241), and 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 scintillator screen according to claim 8 or 9 to obtain a high-purity activator for use as a luminescent dopant for cesium iodide crystals and scintillator screens.

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