Device and method for preparing calcium fluoride microspheres by high-temperature fluidization

Abstract

The application relates to the technical field of calcium fluoride sludge recycling, and provides a device and method for preparing calcium fluoride microspheres through high-temperature fluidization, the device comprising a fluidized bed reaction furnace, a feeding assembly and a cyclone separator, the fluidized bed reaction furnace is provided with a combustion cavity, a feeding port communicated with the combustion cavity, a cooling cavity communicated with the combustion cavity and a discharging port communicated with the cooling cavity, and the combustion cavity is arranged above the cooling cavity along the height direction of the fluidized bed reaction furnace; the feeding assembly is communicated with the combustion cavity through the feeding port, and the feeding assembly is used for mixing calcium fluoride sludge and a mineralizing agent; the cyclone separator is provided with a feeding end, a first discharging end and a second discharging end, the feeding end is communicated with the discharging port, the first discharging end is communicated with the combustion cavity, and the second discharging end is used for outputting calcium fluoride microspheres; and the application can solve the problems that calcium fluoride needs to be mechanically broken, ground, screened and controlled in particle size, and the operation is complicated and the particle size distribution of calcium fluoride particles is uneven.

Description

Technical Field

[0001] This application relates to the field of calcium fluoride sludge reuse technology, and in particular to an apparatus and method for preparing calcium fluoride microspheres by high-temperature fluidization. Background Technology

[0002] Currently, calcium salt precipitation is the mainstream process for treating fluoride-containing wastewater, but it produces calcium fluoride sludge as a byproduct.

[0003] Among the related technologies, a process of directly calcining calcium fluoride sludge in a rotary kiln at a high temperature of 1100℃ is used. This process melts the sludge into blocks at high temperature, and calcium fluoride can be used as a raw material for the preparation of hydrofluoric acid.

[0004] However, calcium fluoride requires mechanical crushing, grinding and sieving, and particle size control, which presents problems such as complex operation and uneven particle size distribution. Summary of the Invention

[0005] This application provides an apparatus and method for preparing calcium fluoride microspheres by high-temperature fluidization, which can solve the problems of complex operation and uneven particle size distribution of calcium fluoride, which require mechanical crushing, grinding and sieving and particle size control of calcium fluoride.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] In a first aspect, this application provides an apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres, comprising:

[0008] A fluidized bed reactor has a combustion chamber and a feed inlet connected to the combustion chamber, as well as a cooling chamber connected to the combustion chamber and a discharge inlet connected to the cooling chamber. Along the height direction of the fluidized bed reactor, the combustion chamber is located above the cooling chamber.

[0009] The feeding assembly is connected to the combustion chamber through the feed inlet. The feeding assembly is used to mix calcium fluoride sludge and mineralizer.

[0010] The cyclone separator has a feed end, a first discharge end and a second discharge end connected together. The feed end is connected to the discharge port, the first discharge end is connected to the combustion chamber, and the second discharge end is used to output calcium fluoride microspheres.

[0011] In some implementations, the feeding assembly includes:

[0012] The mixer has a mixing chamber and a feeding port and a discharging port connected to the mixing chamber. The feeding port is used to feed calcium fluoride sludge and mineralizer into the mixing chamber.

[0013] The feed pipe has one end connected to the discharge port and the other end connected to the feed port.

[0014] The discharge valve is connected to the feed pipe;

[0015] The powder conveying component is connected to the feed pipe and is located at the end of the discharge valve away from the mixer along the length of the feed pipe.

[0016] In some implementations, it also includes:

[0017] The burner is located in the fluidized bed reactor, with its ignition end situated inside the combustion chamber.

[0018] A gas distributor is installed in the fluidized bed reactor. The gas distributor is used to deliver combustible gas and combustion-supporting gas toward the combustion chamber.

[0019] The first thermocouple is located in the combustion chamber and is used to measure the internal temperature of the combustion chamber.

[0020] The first pressure sensor is located in the combustion chamber and is used to measure the internal pressure of the combustion chamber.

[0021] A first gas distribution plate is disposed inside the combustion chamber and is used to deliver airflow toward the combustion chamber.

[0022] In some implementations, it also includes:

[0023] A flow guiding assembly is located inside the combustion chamber, and the flow guiding assembly connects the combustion chamber and the cooling chamber;

[0024] The diversion components include:

[0025] The flow guide is detachably connected to the inner wall of the fluidized bed reactor.

[0026] An atomizing nozzle is connected to the flow guide and is located inside the cooling chamber.

[0027] In some implementations, it also includes:

[0028] A cylindrical partition is disposed in the cooling cavity and connected to the flow guide. The cylindrical partition has an inner cavity and a through hole communicating with the inner cavity. The inner cavity is connected to the cooling cavity through the through hole.

[0029] The second gas distribution plate is located in the inner cavity and is used to deliver cooling airflow toward the inner cavity.

[0030] The third gas distribution plate is located inside the cooling chamber along the height of the fluidized bed reactor. The third gas distribution plate is spaced below the second gas distribution plate and is used to deliver cooling airflow toward the cooling chamber.

[0031] In some implementations, it also includes:

[0032] A first gas conveying assembly, one end of which is connected to a first discharge end, and the other end of which is connected to a first gas distribution plate, is used to convey the gas flow from the first discharge end to the first gas distribution plate.

[0033] The second gas delivery component is connected to the second gas distribution plate and is used to deliver the cooling airflow to the second gas distribution plate.

[0034] The third gas delivery component is connected to the third gas distribution plate. The third gas delivery component is used to deliver the cooling airflow to the third gas distribution plate. The third gas delivery component and the second gas delivery component are connected in parallel.

[0035] The first induced draft fan is connected to the second gas conveying assembly and the third gas conveying assembly respectively;

[0036] A cooling coil is arranged around the outside of the third gas delivery assembly. The cooling coil is used to cool the third gas delivery assembly.

[0037] In some embodiments, the first gas delivery assembly includes:

[0038] The first conveyor has one end connected to the first gas distribution plate and the other end connected to the first discharge end.

[0039] The second induced draft fan is connected to the first conveyor;

[0040] A first electric diamond-shaped valve is connected to the first conveying component;

[0041] A first thermal mass flow meter is connected and installed in the first conveying component;

[0042] The second thermocouple is located on the first conveying member. Along the length of the first conveying member, the second induced draft fan, the first electric diamond valve, the first thermal mass flow meter, and the second thermocouple are arranged sequentially at intervals.

[0043] An exhaust pipe is connected to the first conveyor and is located between the second induced draft fan and the first electric diamond valve along the length of the first conveyor.

[0044] An exhaust valve is located on the exhaust pipe.

[0045] In some embodiments, the second gas delivery assembly includes:

[0046] The second conveyor has one end connected to the second gas distribution plate and the other end connected to the first induced draft fan.

[0047] A second electric diamond-shaped valve is connected to the second conveying component;

[0048] The second thermal mass flow meter is connected to the second conveying component.

[0049] In some embodiments, the fluidized bed reactor has a support base, a cooling coil is arranged in a ring within the support base, and a third gas delivery assembly passes through the support base;

[0050] The third gas delivery assembly includes:

[0051] The third conveyor is connected at one end to the third gas distribution plate and at the other end to the first induced draft fan.

[0052] The third electric diamond-shaped valve is connected to the third conveying component;

[0053] The third thermal mass flow meter is connected to the third conveying component.

[0054] In some implementations, it also includes:

[0055] An air filter is connected to the air inlet of the first induced draft fan;

[0056] The third thermocouple is located at the outlet of the first induced draft fan;

[0057] The fourth thermocouple is located on the support base;

[0058] The fifth thermocouple is located in the cooling chamber.

[0059] In some implementations, it also includes:

[0060] An automatic feeder is connected and installed at the second discharge end;

[0061] The cooling tower is connected to the automatic discharge device;

[0062] An online particle size analyzer is connected to the finished product collection end of the cooling tower and is used to analyze the particle size of calcium fluoride microspheres.

[0063] The control unit is electrically connected to the online particle size analyzer. Based on the particle size obtained from the online particle size analyzer, the control unit controls at least one of the following actuators: a discharge valve, a separate conveyor, a burner, a first thermocouple, a first pressure sensor, a first induced draft fan, a second induced draft fan, a first electric rhomboid valve, a first thermal gas mass flow meter, a second thermocouple, an exhaust valve, a second electric rhomboid valve, a second thermal mass flow meter, a third electric rhomboid regulating valve, a third thermal gas mass flow meter, a third thermocouple, a fourth thermocouple, a fifth thermocouple, a combustible gas electric rhomboid regulating valve, a combustible gas thermal mass flow meter, an auxiliary gas electric rhomboid regulating valve, and an auxiliary gas thermal mass flow meter.

[0064] Secondly, this application provides a method for preparing calcium fluoride microspheres by high-temperature fluidization, the method comprising an apparatus suitable for preparing calcium fluoride microspheres by high-temperature fluidization, and the method including the following steps:

[0065] The calcium fluoride sludge and mineralizing agent in the feed assembly are conveyed to the combustion chamber of the fluidized bed reactor through the feed inlet;

[0066] The calcium fluoride sludge and mineralizer in the combustion chamber are melted;

[0067] The molten calcium fluoride sludge and mineralizing agent are transported to the cooling chamber to form calcium fluoride microspheres;

[0068] The calcium fluoride microspheres in the cooling chamber are conveyed to a cyclone separator to separate them into calcium fluoride microspheres of a preset particle size and calcium fluoride microspheres of a smaller particle size;

[0069] Small-diameter calcium fluoride microspheres are delivered to the combustion chamber;

[0070] Output calcium fluoride microspheres with a preset particle size.

[0071] This high-temperature fluidized bed reactor for preparing calcium fluoride microspheres utilizes a fluidized bed reactor, a feeding assembly, and a cyclone separator. The feed assembly allows calcium fluoride sludge and mineralizing agent to melt in the combustion chamber, recrystallize in the cooling chamber, and then exit through the cyclone separator, thus forming calcium fluoride microspheres. The combustion chamber melts the calcium fluoride sludge and mineralizing agent, triggering a eutectic reaction between them, achieving rapid melting of the particle surface and reconstruction of active sites. Positioning the combustion chamber above the cooling chamber allows the molten calcium fluoride sludge and mineralizing agent to drip into the cooling chamber. During the flow, the molten calcium fluoride droplets undergo forced convection heat exchange with the low-temperature gas, causing a rapid drop in surface temperature and triggering a homogeneous nucleation process in the supersaturated liquid phase, forming nanoscale initial crystal nuclei. These nanoscale primary crystal nuclei serve as active sites for calcium fluoride crystal growth within the cooling chamber. Based on the Ostwald ripening mechanism, nanoscale primary crystal nuclei continuously capture surrounding molten calcium fluoride molecules through surface adsorption and diffusion. In the turbulent flow field unique to fluidized bed reactors, particle collisions occur frequently, promoting the uniform spreading and epitaxial growth of molten droplets on the surface of the crystal nuclei. This allows the crystals to preferentially grow along the crystal planes, ultimately forming large-diameter, regular crystals.

[0072] Therefore, the high-temperature fluidized bed preparation apparatus for calcium fluoride microspheres provided in the embodiments of this application can solve the problems of complex operation and uneven particle size distribution of calcium fluoride, which require mechanical crushing, grinding and sieving and particle size control of calcium fluoride. Attached Figure Description

[0073] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0074] Figure 1 A schematic diagram of the main structure of the apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres provided in the embodiments of this application;

[0075] Figure 2 A flowchart illustrating the method for preparing calcium fluoride microspheres by high-temperature fluidization according to an embodiment of this application.

[0076] Explanation of reference numerals in the attached figures:

[0077] 100-Fluidized bed reactor; 101-Combustion chamber; 102-Feed inlet; 103-Cooling chamber; 104-Discharge outlet; 105-Support base;

[0078] 200 - Feed assembly; 201 - Mixer; 202 - Feed pipe; 203 - Discharge valve; 204 - Powder conveying component;

[0079] 300 - Cyclone separator; 301 - Feed end; 302 - First discharge end; 303 - Second discharge end;

[0080] 400 - Burner; 401 - Gas distributor; 402 - First thermocouple; 403 - First pressure sensor; 404 - First gas distribution plate;

[0081] 500 - Flow guiding assembly; 501 - Flow guiding element; 502 - Atomizing nozzle;

[0082] 600 - Cylindrical segment; 601 - Second gas distribution plate; 602 - Third gas distribution plate;

[0083] 700-First gas conveying assembly; 7001-First conveying component; 7002-Second induced draft fan; 7003-First electric diamond valve; 7004-First thermal mass flow meter; 7005-Second thermocouple; 7006-Exhaust pipe; 7007-Exhaust valve;

[0084] 701-Second gas conveying assembly; 7011-Second conveying component; 7012-Second electric rhomboid valve; 7013-Second thermal mass flow meter;

[0085] 702-Third gas conveying assembly; 7021-Third conveying component; 7022-Third electric rhomboid valve; 7023-Third thermal mass flow meter;

[0086] 703 - First induced draft fan; 704 - Cooling coil;

[0087] 800 - Air filter; 801 - Third thermocouple; 802 - Fourth thermocouple; 803 - Fifth thermocouple; 804 - Automatic discharge device; 806 - Cooling tower; 807 - Online particle size analyzer; 808 - Control components. Detailed Implementation

[0088] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0089] In existing technologies, the water in fluoride-containing wastewater from the photovoltaic and semiconductor industries has a relatively high degree of crystallinity, and the resulting sludge contains ≥90% calcium fluoride, making it a high-quality raw material for the preparation of hydrofluoric acid. However, the particle size of calcium fluoride sludge formed by chemical precipitation processes is generally ≤10μm, which is significantly different from the 50μm to 100μm feed particle size required by hydrofluoric acid production equipment. If directly applied to hydrofluoric acid production, it will lead to many problems such as poor material flowability, insufficient reaction interface, and dust, severely restricting its industrial application value.

[0090] Currently, for low-concentration fluoride-containing wastewater, particle growth can be controlled during the wastewater treatment stage through chemical crystallization. By adjusting crystallization conditions, the particle size can be reduced to 1mm to 3mm, followed by grinding and crushing to 50μm to 100μm to meet the needs of hydrofluoric acid production. However, for fluoride-containing wastewater with a fluoride ion concentration ≥500mg / L, the crystallization kinetics are difficult to control under high-concentration systems, easily forming fine particles. If a large proportion of reflux is used to promote crystal growth, it will lead to a sharp increase in equipment load, high operating costs, and a significant reduction in economic efficiency, making large-scale application difficult.

[0091] Furthermore, existing technologies include a process that directly calcines calcium fluoride sludge in a rotary kiln at a high temperature of 1100℃. This process melts the sludge into blocks at high temperatures, and subsequent particle size control relies on mechanical crushing, grinding, and screening equipment. While this process can achieve a certain degree of particle size control, the high-temperature calcination consumes a lot of energy, and the mechanical crushing process inevitably results in uneven particle size distribution and excessive fine powder content, failing to meet the stringent requirements for material uniformity in hydrofluoric acid production.

[0092] To overcome the shortcomings of existing technologies, a fluidized bed reactor, a feeding assembly, and a cyclone separator are incorporated. This allows the calcium fluoride sludge and mineralizing agent in the feeding assembly to melt in the combustion chamber, recrystallize in the cooling chamber, and then be output through the cyclone separator, enabling the calcium fluoride sludge to form calcium fluoride microspheres. The combustion chamber melts the calcium fluoride sludge and mineralizing agent, triggering a eutectic reaction between the mineralizing agent and calcium fluoride, achieving rapid melting of the particle surface and reconstruction of active sites. Positioning the combustion chamber above the cooling chamber allows the molten calcium fluoride sludge and mineralizing agent to drip into the interior of the cooling chamber. During the flow, the molten calcium fluoride droplets undergo forced convection heat exchange with the low-temperature gas, causing a rapid drop in surface temperature and triggering a homogeneous nucleation process in the supersaturated liquid phase, forming nanoscale initial crystal nuclei. These nanoscale primary crystal nuclei serve as active sites for calcium fluoride crystal growth within the cooling chamber. Based on the Ostwald ripening mechanism, the nanoscale primary crystal nuclei continuously capture surrounding molten calcium fluoride molecules through surface adsorption and diffusion. In the turbulent flow field unique to fluidized bed reactors, particle collisions occur frequently, promoting the uniform spreading and epitaxial growth of molten droplets on the surface of crystal nuclei. This allows crystals to grow preferentially along crystal planes, ultimately forming large-diameter regular crystals.

[0093] Therefore, the high-temperature fluidized bed preparation apparatus for calcium fluoride microspheres provided in the embodiments of this application can solve the problems of complex operation and uneven particle size distribution of calcium fluoride, which require mechanical crushing, grinding and sieving and particle size control of calcium fluoride.

[0094] The contents of this application will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can have a clearer and more detailed understanding of the contents of this application.

[0095] like Figure 1 As shown in the embodiment of this application, an apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres is provided, including: a fluidized bed reactor 100, a feed assembly 200, and a cyclone separator 300. The fluidized bed reactor 100 has a combustion chamber 101 and a feed inlet 102 communicating with the combustion chamber 101, a cooling chamber 103 communicating with the combustion chamber 101, and a discharge outlet 104 communicating with the cooling chamber 103. Along the height direction of the fluidized bed reactor 100, the combustion chamber 101... 1. Located above the cooling chamber 103; the feeding assembly 200 is connected to the combustion chamber 101 through the feeding port 102, and the feeding assembly 200 is used to mix calcium fluoride sludge and mineralizer; the cyclone separator 300 has a connected feeding end 301, a first discharge end 302 and a second discharge end 303, the feeding end 301 is connected to the discharge port 104, the first discharge end 302 is connected to the combustion chamber 101, and the second discharge end 303 is used to output calcium fluoride microspheres.

[0096] The following sections provide a detailed description of the specific structure of the apparatus and method for preparing calcium fluoride microspheres by high-temperature fluidization, as well as various possible implementation methods.

[0097] It should be noted that, since the melting point of calcium fluoride sludge is approximately 1000℃, this application achieves melting temperature control by adding a specific mineralizing agent to lower its melting point. The mineralizing agent undergoes a solid-phase reaction within the temperature range of 650℃ to 750℃, generating a eutectic system. Through an ion substitution mechanism, the active components in the mineralizing agent penetrate into the calcium fluoride crystal lattice, disrupting the regularity of the original crystal structure and reducing the ion migration activation energy, thereby lowering the actual melting temperature to 800±50℃. This process utilizes the thermodynamic eutectic effect, ensuring complete melting of calcium fluoride while significantly reducing energy consumption and refractory material costs.

[0098] It should be noted that the active component in the mineralizer can be Al. 3+ Or Si 4+ There are no restrictions here; you can choose according to your actual usage needs.

[0099] It should be noted that the mineralizer can be aluminum oxide or aluminum fluoride, and there are no restrictions. It can be selected according to the actual needs of the application.

[0100] In one embodiment, the mineralizing agent is aluminum oxide.

[0101] Understandably, aluminum oxide has a high melting point and good thermal stability, and it can also form a eutectic mixture with calcium fluoride, thereby lowering the overall melting point and promoting the sintering and densification of calcium fluoride.

[0102] In one embodiment, the mineralizing agent is aluminum fluoride.

[0103] Understandably, aluminum fluoride can lower the melting point of calcium fluoride, thus helping to reduce the melting point of calcium fluoride. It can also improve the fluidity and uniformity of the material, and improve the sintering and densification process of calcium fluoride.

[0104] It should be noted that the feeding assembly 200 provided in the embodiments of this application includes: a mixer 201, a feed pipe 202, a discharge valve 203, and a powder conveying component 204. The mixer 201 has a mixing chamber and a feeding port and a discharge port communicating with the mixing chamber. The feeding port is used to feed calcium fluoride sludge and mineralizer into the mixing chamber. One end of the feed pipe 202 is connected to the discharge port, and the other end of the feed pipe 202 is connected to the feed inlet 102. The discharge valve 203 is connected to the feed pipe 202, and the powder conveying component 204 is connected to the feed pipe 202. Along the length direction of the feed pipe 202, the powder conveying component 204 is located at the end of the discharge valve 203 away from the mixer 201.

[0105] It is understandable that by setting up the mixer 201, the calcium fluoride sludge and mineralizer can be stirred to make the distribution of the calcium fluoride sludge and mineralizer more uniform. After stirring, the calcium fluoride sludge and mineralizer can be conveyed to the combustion chamber 101 through the feed pipe 202, the discharge valve 203, the powder conveying component 204, and the feed port 102.

[0106] Furthermore, the fluidized bed reactor 100 is equipped with a feed distributor, which is connected to the feed pipe 202.

[0107] Understandably, by setting up a feed distributor, calcium fluoride sludge and mineralizer can be more evenly dispersed into the combustion chamber 101, and the feed distributor can also optimize the flow and distribution of materials, thereby improving the production efficiency of the device for preparing calcium fluoride microspheres by high-temperature fluidization.

[0108] Furthermore, the number of dispensing ports can be one or two, with no restriction, and can be selected according to actual usage needs.

[0109] In one embodiment, two inlet ports are provided, wherein the first inlet port is used to add calcium fluoride sludge, and the second inlet port is used to add mineralizer.

[0110] Understandably, by setting up two feeding ports, the distribution of calcium fluoride sludge and mineralizer can be more uniform when feeding materials from both ports simultaneously.

[0111] Furthermore, the mixer 201 includes: a mixer 201 housing, a propeller blade, and a mixing motor. The mixing motor is mounted on the mixer 201 housing, and the propeller blade is fixedly connected to the mixing motor and rotatably connected to the mixer 201 housing.

[0112] Understandably, by setting up the mixer 201 housing, the calcium fluoride sludge powder and mineralizer can be contained, and the stirring motor drives the propeller blades to rotate, so that the calcium fluoride sludge powder and mineralizer can be stirred by the rotation of the propeller blades.

[0113] Specifically, calcium fluoride sludge powder pre-dried to a moisture content of 15% to 20% and a mineralizer are added to a mixer 201. The mixture is then uniformly dispersed through mechanical shearing and convection within the mixer 201. The mixed calcium fluoride sludge powder and mineralizer are then injected into a fluidized bed reactor 100 via a powder conveyor 204. By adjusting the feed rate and material quantity, and by uniformly spraying the material through a feed distributor, a stable fluidized state is ensured within the combustion chamber 101, providing a uniform material distribution basis for the low-temperature melting reaction.

[0114] The apparatus for preparing calcium fluoride microspheres by high-temperature fluidization provided in the embodiments of this application further includes: a burner 400, a gas distributor 401, a first thermocouple 402, a first pressure sensor 403, and a first gas distribution plate 404. The burner 400 is disposed in a fluidized bed reactor, and the ignition end of the burner 400 is located inside the combustion chamber 101. The gas distributor 401 is disposed in the fluidized bed reactor 100 and is used to deliver combustible gas and combustion-supporting gas toward the combustion chamber 101. The first thermocouple 402 is disposed in the combustion chamber 101 and is used to measure the internal temperature of the combustion chamber 101. The first pressure sensor 403 is disposed in the combustion chamber 101 and is used to measure the internal pressure of the combustion chamber 101. The first gas distribution plate 404 is disposed inside the combustion chamber 101 and is used to deliver gas flow toward the combustion chamber 101.

[0115] It is understood that by setting up a burner 400 and a gas distributor 401, the burner 400 can ignite the combustible gas, thereby increasing the temperature inside the combustion chamber 101. In this case, the combustion-supporting gas can promote the combustion of the combustible gas. By setting up a first thermocouple 402 and a first pressure sensor 403, the flow rate or volume of the combustible gas and the combustion-supporting gas can be adjusted based on the temperature and pressure inside the combustion chamber 101, thereby achieving the adjustment of the temperature and pressure inside the combustion chamber 101. By setting up a first gas distributor, airflow can be delivered toward the combustion chamber 101. Through the above implementation method, the calcium fluoride sludge and mineralizer inside the combustion chamber 101 can be in a bubbling fluidized state.

[0116] Furthermore, the first pressure sensor 403 can be a first diaphragm pressure sensor, or a first strain gauge pressure sensor, or other pressure sensors. There are no restrictions here, and the appropriate sensor can be selected according to actual usage requirements.

[0117] It should be noted that the apparatus for preparing calcium fluoride microspheres by high-temperature fluidization provided in the embodiments of this application further includes: a combustible gas supply branch, an auxiliary gas supply branch, and a premixed air inlet. One end of the combustible gas supply branch is used to connect to an external combustible gas source, and the other end of the combustible gas delivery pipe is connected to the premixed air inlet. One end of the auxiliary gas supply branch is used to connect to an external auxiliary gas source, and the other end of the auxiliary gas supply branch is connected to the premixed air inlet. The premixed air inlet is connected to the gas distributor 401.

[0118] It is understandable that by setting up a combustible gas supply branch, the combustible gas in the combustible gas source can be delivered to the gas distributor 401. By setting up an auxiliary gas supply branch, the auxiliary gas in the auxiliary gas source can be delivered to the gas distributor 401. By setting up a premixed air inlet, the combustible gas and the auxiliary gas can be mixed, and the mixed gas can be delivered to the gas distributor 401 to be input into the combustion chamber 101.

[0119] Furthermore, the apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres provided in the embodiments of this application further includes: a combustible gas electric rhomboid regulating valve, a combustible gas thermal mass flow meter, a gas-supporting electric rhomboid regulating valve, and a gas-supporting thermal mass flow meter. The combustible gas electric rhomboid regulating valve and the combustible gas thermal mass flow meter are respectively arranged in the combustible gas supply branch. Along the length direction of the combustible gas supply branch, the premixed air inlet, the combustible gas thermal mass flow meter, and the combustible gas electric rhomboid regulating valve are arranged in sequence at intervals. The gas-supporting electric rhomboid regulating valve and the gas-supporting thermal mass flow meter are respectively arranged in the gas-supporting gas supply branch. Along the length direction of the gas-supporting gas supply branch, the premixed air inlet, the gas-supporting thermal mass flow meter, and the gas-supporting electric rhomboid regulating valve are arranged in sequence at intervals.

[0120] Understandably, by installing a combustible gas-operated electric diamond-shaped regulating valve, the flow rate of combustible gas in the combustible gas supply branch can be controlled, and remote control and automated operation can be achieved, thus improving the automation level and operational convenience of the high-temperature fluidized bed preparation device for calcium fluoride microspheres. By installing a combustible gas thermal mass flow meter, the mass flow rate of combustible gas in the combustible gas supply branch can be dynamically measured, and the combustible gas thermal mass flow meter can detect low-velocity and low-flow-rate gas flows, thus improving the measurement accuracy of combustible gas in the combustible gas supply branch. Similarly, by installing a combustion-supporting gas-operated electric diamond-shaped regulating valve, the flow rate of combustion-supporting gas in the combustion-supporting gas supply branch can be controlled, and remote control and automated operation can be achieved, thus improving the automation level and operational convenience of the high-temperature fluidized bed preparation device for calcium fluoride microspheres. Furthermore, by installing a combustion-supporting gas thermal mass flow meter, the mass flow rate of combustion-supporting gas in the combustion-supporting gas supply branch can be dynamically measured, and the combustion-supporting gas thermal mass flow meter can detect low-velocity and low-flow-rate gas flows, thus improving the measurement accuracy of combustion-supporting gas in the combustion-supporting gas supply branch.

[0121] It should be noted that the outer wall of the fluidized bed reactor 100, where the combustion chamber 101 is located, adopts a high-temperature resistant double-shell structure, filled with high-temperature resistant insulation material. A burner 400 is vertically installed at the top center, and a first gas distribution plate 404 is installed at the bottom. The first gas distribution plate 404 adopts a porous conical structure with an opening ratio of 25%-35% and a gradient pore size distribution. The gas distribution uniformity within the channels is ≥95%, ensuring that the calcium fluoride sludge can stably achieve a fluidized state in the combustion chamber 101. Specifically, the channel layout can be optimized through CFD simulation to ensure that the gas distribution uniformity within the channels is ≥95%.

[0122] In one embodiment, the right side wall of the fluidized bed reactor 100 is provided with an air inlet and equipped with a dual-channel premixed air inlet. The combustible gas supply branch is constructed of SUS304 seamless steel pipe, and consists of a combustible gas electric rhomboid regulating valve with a rated flow coefficient KV=50 and a combustible gas thermal mass flow meter with a measurement range of 0-100 Nm³ / h and an accuracy of ±0.5% connected in series. This combustible gas supply branch is welded to the first air inlet of the premixed air inlet. Furthermore, the auxiliary gas supply branch uses the same specifications of pipe material, the same model of auxiliary gas electric rhomboid regulating valve, and the same model of auxiliary gas thermal mass flow meter, and is welded to the second air inlet of the premixed air inlet.

[0123] Furthermore, the premixed air inlet is connected to the combustion chamber 101 air inlet via a metal hose wrapped with a 50-100mm thick aluminum silicate fiber insulation layer. A gas distributor 401 made of 2507 stainless steel sintered mesh with a thickness of 10mm and an average pore size of 100μm is installed inside the air inlet to enhance the uniformity of the intake gas flow.

[0124] Furthermore, a first thermocouple 402 with a temperature measurement range of 0-1500℃ and a response time of ≤0.5s and a first diaphragm pressure sensor with a range of 0-2MPa and an accuracy of 0.25 are respectively installed on the left side wall of the fluidized bed reactor 100. The probes of both sensors are inserted into the combustion chamber 101 by about 150mm, and the signal output terminals of both sensors are led out through explosion-proof wiring boxes.

[0125] Effect: Pre-dried calcium fluoride sludge powder with a moisture content of 15%-20% and mineralizing agent are injected into the combustion chamber 101 of the fluidized bed reactor 100 via powder conveyor 204. The first gas distribution plate 404 at the bottom of the combustion chamber 101 adopts a gradient porous structure, which can make the fluidizing gas velocity uniformly distributed in the range of 0.5-5m / s and ensure that the powder particles are in a bubbling fluidized state. At the same time, combustible gas and combustion-supporting gas are uniformly distributed in the combustion chamber 101 through the premixed distributor and the gas distributor 401, and the axial burner 400 at the top sprays out a high-temperature flame, thereby forming a high-temperature flame region in the combustion chamber 101. The temperature of the combustion chamber 101 is monitored in real time by the first thermocouple 402, and then the two electric diamond-shaped regulating valves of the combustible gas and combustion-supporting gas supply branches are adjusted to form a closed-loop temperature control system, so that the temperature of the combustion chamber 101 reaches 800-900℃. Within this region, calcium fluoride sludge powder and mineralizer undergo heat transfer via radiation and convection coupling. Under the scorching of a high-temperature combustion flame, they absorb a large amount of heat, causing the surface temperature to rise rapidly to 800±50℃. This triggers a eutectic reaction between the mineralizer and calcium fluoride, achieving rapid melting of the particle surface and reconstruction of active sites.

[0126] The apparatus for preparing calcium fluoride microspheres by high-temperature fluidization provided in the embodiments of this application further includes: a flow guiding component 500, which is disposed in the combustion chamber 101 and connects the combustion chamber 101 and the cooling chamber 103. The flow guiding component 500 includes: a flow guiding element 501 and an atomizing nozzle 502. The outer ring of the flow guiding element 501 is detachably connected to the inner wall of the fluidized bed reactor 100. The atomizing nozzle 502 is connected to the flow guiding element 501 and is located in the cooling chamber 103.

[0127] It is understood that the combustion chamber 101 and the cooling chamber 103 can be separated by providing a detachable flow guide 501. Through the above implementation, the combustion chamber 101 and the cooling chamber 103 can be connected through the flow guide 501 and the atomizing nozzle 502, so that the high-temperature calcium fluoride can enter the cooling chamber 103 from the combustion chamber 101, thereby cooling it down.

[0128] In one embodiment, the outer wall of the fluidized bed reactor 100 corresponding to the location of the cooling chamber 103 adopts a high-temperature resistant double-shell structure, and is filled with high-temperature resistant heat insulation material. A detachable flow guide 501 is vertically installed at the top center of the cooling chamber 103. The upper end of the flow guide 501 has an flared angle of 120 degrees and presents a funnel-mouth flow guiding structure, and then tapers downward to form a cylindrical section with a diameter of 200 mm. The lower end of the flow guide 501 forms a cylindrical diverter. The interior of the diverter is uniformly arranged in a circumferential gradient. A molten atomizing nozzle 502 with a high temperature resistance of 1500℃ is used. The atomizing nozzle 502 adopts a tungsten carbide-cobalt hard alloy coating, i.e., WC-Co hard alloy coating. The cone angle of the atomized spray is 90 degrees to 120 degrees and the angle is adjustable.

[0129] Furthermore, multiple atomizing nozzles 502 are provided, and multiple atomizing nozzles 502 are arranged at intervals along the circumferential direction of the flow divider.

[0130] It is understood that, through the above implementation method, after the calcium fluoride sludge powder completes the melting reaction, it is collected by the guide element 501 and enters the cooling chamber 103 through multiple atomizing nozzles 502 to achieve crystallization.

[0131] The apparatus for preparing calcium fluoride microspheres by high-temperature fluidization provided in the embodiments of this application further includes: a cylindrical dividing member 600, a second gas distribution plate 601, and a third gas distribution plate 602. The cylindrical dividing member 600 is disposed in the cooling chamber 103 and connected to the flow guide member 501. The cylindrical dividing member 600 has an inner cavity and a through hole communicating with the inner cavity. The inner cavity is connected to the cooling chamber 103 through the through hole. The second gas distribution plate 601 is disposed in the inner cavity and delivers cooling gas flow toward the inner cavity. The third gas distribution plate 602 is disposed in the cooling chamber 103. Along the height direction of the fluidized bed reactor 100, the third gas distribution plate 602 is spaced below the second gas distribution plate 601 and is used to deliver cooling gas flow toward the cooling chamber 103.

[0132] It is understood that, through the above-described embodiments, the second gas distribution plate 601 can deliver cooling airflow toward the inner cavity, and the cooling airflow in the inner cavity can enter the cooling chamber 103 through the through holes, thereby reducing the internal temperature of the cooling chamber 103. The third gas distribution plate 602 can also deliver cooling airflow toward the cooling chamber 103, further reducing the internal temperature of the cooling chamber 103. By positioning the third gas distribution plate 602 at intervals below the second gas distribution plate 601 along the height direction of the fluidized bed reactor 100, the distribution of cooling gas within the cooling chamber 103 can be made more uniform.

[0133] In one embodiment, a cylindrical dividing member 600 is fixedly connected to the center of the bottom of the cylindrical diverter of the guide member 501, thereby dividing the cooling chamber 103 into a cold zone I located inside the chamber and a cold zone II located outside the chamber; wherein, cooling zone I is a rapid cooling zone and cold zone II is a normal cooling zone. The second gas distribution plate 601 provided at the bottom of cooling zone I adopts a porous conical structure design with an opening ratio of 25%-35% and a gradient distribution of pore size, and a gas distribution uniformity of ≥95%, which can achieve uniform diffusion of cooling gas; the third gas distribution plate 602 provided at the bottom of cooling zone II adopts a porous conical structure design with an opening ratio of 25%-35% and a gradient distribution of pore size, and a gas distribution uniformity of ≥95%, which can achieve uniform diffusion of cooling gas.

[0134] Understandably, a second gas distribution plate 601 is installed at the bottom of cooling zone I, allowing the cooling airflow to uniformly pass through the inner cavity and through holes at a velocity of 1.5-3 m / s, forming a gas-solid countercurrent heat exchange field. Molten calcium fluoride droplets undergo forced convection heat exchange with the low-temperature gas during the flow process, causing a rapid drop in surface temperature and triggering a homogeneous nucleation process in the supersaturated liquid phase, forming nanoscale initial crystal nuclei with a particle size of approximately 50-100 nm. These nanoscale primary crystal nuclei move rapidly through the cylindrical partition 600 with the airflow to cooling zone II, serving as active sites for calcium fluoride crystal growth. A third gas distribution plate 602 is installed at the bottom of cooling zone II, allowing the cooling gas to uniformly pass through the cooling cavity 103 at a velocity of 0.5-1.2 m / s. Within cooling zone II, based on the Ostwald ripening mechanism, the nanoscale primary crystal nuclei continuously capture surrounding molten calcium fluoride molecules through surface adsorption and diffusion. In the unique turbulent flow field of the fluidized bed reactor 100, particle collisions occur frequently, promoting the uniform spreading and epitaxial growth of molten droplets on the crystal nucleus surface. This allows the crystals to preferentially grow along the crystal plane, ultimately forming large-diameter, regular crystals. The process also allows for the directional control of crystal growth by adjusting the cooling rate and gas-solid contact time.

[0135] Furthermore, the inlet temperature of the cooling gas is ≤32℃.

[0136] The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres provided in the embodiments of this application further includes: a first gas conveying component 700, a second gas conveying component 701, a third gas conveying component 702, a first induced draft fan 703, and a cooling coil 704. One end of the first gas conveying component 700 is connected to a first discharge end 302, and the other end of the first gas conveying component 700 is connected to a first gas distribution plate 404. The first gas conveying component 700 is used to convey the gas flow from the first discharge end 302 to the first gas distribution plate 404. The second gas conveying component 701 is connected to and disposed on the second gas distribution plate 601. The second gas delivery assembly 701 is used to deliver the cooling airflow to the second gas distribution plate 601. The third gas delivery assembly 702 is connected to the third gas distribution plate 602 and is used to deliver the cooling airflow to the third gas distribution plate 602. The third gas delivery assembly 702 and the second gas delivery assembly 701 are connected in parallel. The first induced draft fan 703 is connected to the second gas delivery assembly 701 and the third gas delivery assembly 702 respectively. The cooling coil 704 is arranged around the outside of the third gas delivery assembly 702 and is used to cool the third gas delivery assembly 702.

[0137] It is understood that, through the above-described embodiments, the airflow exiting the cooling chamber 103 can pass through the cyclone separator, and then be conveyed through the first discharge end 302 and the first gas conveying assembly 700 to the first gas distribution plate 404, thereby entering the combustion chamber 101, thus improving the utilization rate of the airflow within the cooling chamber 103. The airflow output from the first induced draft fan 703 can also be conveyed through the second gas conveying assembly 701 to the second gas distribution plate 601 to reach the inner cavity. Furthermore, the airflow output from the first induced draft fan 703 can also be conveyed through the third gas conveying assembly 702 to the third gas distribution plate 602. The second gas conveying assembly 701 and the third gas conveying assembly 702 are arranged in parallel, allowing both to be conveyed by a single first induced draft fan 703 for cooling airflow, thereby improving the utilization rate of the first induced draft fan 703. By setting up the cooling coil 704, the third gas delivery assembly 702 can be cooled down, so that the temperature of the airflow inside the third gas delivery assembly 702 can be further reduced, thereby reducing the internal temperature of the cooling airflow flowing into the cooling chamber 103.

[0138] The first gas delivery assembly 700 provided in the embodiments of this application includes: a first delivery component 7001, a second induced draft fan 7002, a first electric diamond valve 7003, a first thermal mass flow meter 7004, a second thermocouple 7005, an exhaust pipe 7006, and an exhaust valve 7007. One end of the first conveying component 7001 is connected to the first gas distribution plate 404, and the other end of the first conveying component 7001 is connected to the first discharge end 302. The second induced draft fan 7002 is connected to the first conveying component 7001. The first electric rhomboid valve 7003 is connected to the first conveying component 7001. The first thermal mass flow meter 7004 is connected to the first conveying component 7001. The second thermocouple 7005 is located on the first conveying component 7001. Along the length of the first conveying component 7001, the second induced draft fan 7002, the first electric rhomboid valve 7003, the first thermal mass flow meter 7004, and the second thermocouple 7005 are spaced apart. The exhaust pipe 7006 is connected to the first conveying component 7001. Along the length of the first conveying component 7001, the exhaust pipe 7006 is located between the second induced draft fan 7002 and the first electric rhomboid valve 7003. The exhaust valve 7007 is located on the exhaust pipe 7006.

[0139] It is understood that, through the above-described embodiments, the airflow in the cooling chamber 103 can pass through the cyclone separator 300, the first conveying component 7001, the second induced draft fan 7002, the first electric rhomboid valve 7003, and the first thermal mass flow meter 7004 before flowing into the first gas distribution plate 404, thereby conveying the airflow in the cooling chamber 103 to the combustion chamber 101 and improving the utilization rate of the airflow in the cooling chamber 103. By setting the first electric rhomboid regulating valve, the flow rate of the airflow in the first conveying component 7001 can be controlled, and remote control and automated operation can be realized, which can improve the automation level and operational convenience of the device for preparing calcium fluoride microspheres by high-temperature fluidization. By setting the first thermal mass flow meter 7004, the mass flow rate of the airflow in the first conveying component 7001 can be dynamically measured, and the first thermal mass flow meter 7004 can detect low-velocity and low-flow-rate gas flow, which can improve the measurement accuracy of the airflow in the first conveying component 7001. By setting up an exhaust pipe 7006 and an exhaust valve 7007, exhaust treatment can be performed on the first conveyor 7001 to control the pressure in the combustion chamber 101, and the waste heat of the exhaust pipe 7006 can also be used to dry the original calcium fluoride sludge.

[0140] It should be noted that the first conveying component 7001 can be a heat-resistant flexible hose with an inner diameter of DN100-DN150, or a seamless steel pipe with an inner diameter of DN100-DN150. There are no restrictions here, and the appropriate type can be selected according to actual usage requirements.

[0141] In one embodiment, the feed end 301 of the cyclone separator 300 is sealed to the discharge port 104 of the cooling chamber 103 via a seamless steel pipe with an expansion joint. The inner diameter of the seamless steel pipe is DN200-DN250. The first discharge end 302 at the top of the cyclone separator 300 is connected to the air inlet of the second induced draft fan 7002 via a first conveyor 7001. The second induced draft fan 7002 provides driving circulation force for the cyclone separator. The first conveyor 7001 is sequentially connected to... The system is equipped with a first electric diamond-shaped regulating valve with a KV=80 and a leakage class of VI, a second thermal mass flow meter 7013 with a measurement range of 0-500 Nm³ / h and an accuracy of ±0.5%, and a second thermocouple 7005 with a temperature measurement range of 0-300℃ and a response time ≤1s. These components are then connected to a first gas distribution plate 404 in the combustion chamber 101 of the fluidized bed reactor 100 to provide power circulation for the fluidized bed reactor 100. The exhaust pipe 7006 has an inner diameter of DN80-DN100 and is equipped with a sintered metal filter element made of 316L stainless steel fiber felt and an exhaust valve 7007 with a KV=60 to achieve purified gas emission.

[0142] Furthermore, the average pore size of the stainless steel fiber felt is 5 μm.

[0143] Understandably, during the crystallization process, the particles continuously increase in size as the crystal nuclei grow. When they reach the target particle size and possess sufficient mechanical strength, gas-solid separation is achieved by the cyclone separator 300 at the top of the cooling zone. The cyclone separator 300 is driven by a second induced draft fan 7002, which draws the airflow containing coarse particles from the cooling chamber 103 of the fluidized bed reactor 100 into the cyclone separator 300. Under the action of centrifugal force, the coarse particles are thrown against the wall of the separator and, under the action of gravity, spiral downwards near the wall, entering the automatic discharge device 804 and further falling into the cooling tower 806 below. At the same time, the fine particles discharged from the first discharge end 302 of the cyclone separator 300, along with the airflow, return to the combustion chamber 101 of the fluidized bed reactor 100 through the first gas conveying assembly 700, forming a closed-loop processing system. The particle size of the fine particles is approximately < 10 μm, and the temperature of the airflow is approximately 300-500℃. In this system, fine particles undergo further melting and granulation. The high-temperature airflow, after passing through the second induced draft fan 7002, serves as a fluidizing medium. Under the action of the first gas distribution plate 404 within the combustion chamber 101, the calcium fluoride sludge powder maintains a fluidizing gas velocity of 0.5-5 m / s. Simultaneously, the waste heat carried by the airflow preheats the calcium fluoride sludge through radiation and convection heat transfer, reducing combustion energy consumption. Furthermore, the above-described embodiment can also adjust the fluidizing gas velocity and pressure within the cooling chamber 103 in real time and use it for pre-drying the raw calcium fluoride sludge material. Pre-drying refers to drying the calcium fluoride sludge with a moisture content of 40% to a moisture content of 15-20%. This circulating process fully utilizes the gas-solid circulation characteristics of the fluidized bed reactor 100, allowing the fine particles to undergo multiple melting-crystallization processes, significantly improving material conversion rate while substantially reducing fuel consumption.

[0144] The second gas delivery assembly 701 provided in the embodiments of this application includes: a second delivery member 7011, a second electric rhomboid valve 7012, and a second thermal mass flow meter 7013. One end of the second delivery member 7011 is connected to the second gas distribution plate 601, and the other end of the second delivery member 7011 is connected to the first induced draft fan 703. The second electric rhomboid valve 7012 is connected to the second delivery member 7011, and the second thermal mass flow meter 7013 is connected to the second delivery member 7011.

[0145] It is understood that, through the above-described embodiments, the airflow from the first induced draft fan 703 can pass through the second conveying component 7011, the second electric rhomboid valve 7012, and the second thermal mass flow meter 7013 before flowing into the second gas distribution plate 601. By setting the second electric rhomboid regulating valve, the flow rate of the airflow within the second conveying component 7011 can be controlled, enabling remote control and automated operation, thus improving the automation level and ease of operation of the high-temperature fluidized bed calcium fluoride microsphere preparation device. By setting the second thermal mass flow meter 7013, the mass flow rate of the airflow within the second conveying component 7011 can be dynamically measured, and the second thermal mass flow meter 7013 can detect low-velocity and low-flow-rate gas flows, thereby improving the measurement accuracy of the airflow within the second conveying component 7011.

[0146] The fluidized bed reactor 100 provided in the embodiments of this application has a support base 105, a cooling coil 704 is arranged in a ring within the support base 105, and a third gas conveying assembly 702 passes through the support base 105. The third gas conveying assembly 702 includes: a third conveying member 7021, a third electric rhomboid valve 7022, and a third thermal mass flow meter 7023. One end of the third conveying member 7021 is connected to the third gas distribution plate 602, and the other end of the third conveying member 7021 is connected to the first induced draft fan 703. The third electric rhomboid valve 7022 is connected to the third conveying member 7021, and the third thermal mass flow meter 7023 is connected to the third conveying member 7021.

[0147] Understandably, the support base 105 supports the fluidized bed reactor 100 and accommodates the cooling coil 704. The cooling coil 704 also cools the support base 105 and the third conveying component 7021. Through this embodiment, the airflow from the first induced draft fan 703 can pass through the third conveying component 7021, the third electric rhomboid valve 7022, and the third thermal mass flow meter 7023 before flowing into the third gas distribution plate 602. The third electric rhomboid regulating valve controls the flow rate within the third conveying component 7021, enabling remote control and automated operation, thus improving the automation level and ease of operation of the high-temperature fluidized bed preparation device for calcium fluoride microspheres. By setting a third thermal mass flow meter 7023, the mass flow rate of the airflow in the third conveying component 7021 can be dynamically measured. The third thermal mass flow meter 7023 can detect gas flow with low velocity and small flow rate, which can improve the measurement accuracy of the airflow in the third conveying component 7021.

[0148] In one embodiment, the support base 105 adopts a hollow structure design, and a cooling coil 704 is provided inside the support base 105. The cooling coil 704 has cooling water inlet and outlet, and a fourth thermocouple 802 is installed on the upper part of the support base 105.

[0149] Understandably, the support base 105 provides the fluidized bed reactor 100 with both rigid support and thermal protection. The support base 105 adopts a hollow structure design, integrating a cooling coil 704 system internally. Through cooling water inlets and outlets, it achieves circulating heat dissipation, keeping the surface temperature of the support base 105 below 60℃, thus preventing deformation of the equipment foundation due to high-temperature conduction. A fourth thermocouple 802 is installed on the upper part of the support base 105. The fourth thermocouple 802 has a temperature measurement range of 0-300℃ and a response time ≤1s, allowing for real-time monitoring of temperature changes and coordinated adjustment of cooling water flow, forming a closed-loop thermal protection system to ensure the support stability and structural safety of the fluidized bed reactor 100 under high-temperature conditions.

[0150] It should be noted that the second conveying component 7011 can be a seamless steel pipe with an inner diameter of DN60-DN80, or a heat-resistant flexible hose with an inner diameter of DN60-DN80. There are no restrictions here, and it can be selected according to the actual use requirements.

[0151] It should be noted that the third conveying component 7021 can be a seamless steel pipe with an inner diameter of DN120-DN150, or a heat-resistant flexible hose with an inner diameter of DN120-DN150. There are no restrictions here, and it can be selected according to the actual use requirements.

[0152] In one embodiment, the third gas distribution plate 602 is connected to the outlet of the first induced draft fan 703 via a second seamless steel pipe of DN120-DN150. The third conveying component 7021 is connected in series with a third electric rhomboid regulating valve with a rated flow coefficient KV=50 and a third thermal mass flow meter 7023 with a measurement range of 0-300Nm³ / h and an accuracy of ±0.5%. The second gas distribution plate 601 assembly is connected to the outlet of the first induced draft fan 703 via a seamless steel pipe of DN60-DN80. The second conveying component 7011 is connected in series with a fourth electric rhomboid regulating valve and a fourth thermal mass flow meter of the same type.

[0153] It is understood that, through the above implementation method, the airflow of the first induced draft fan 703 can be delivered to the second gas distribution plate 601 and the third gas distribution plate 602.

[0154] The apparatus for preparing calcium fluoride microspheres by high-temperature fluidization provided in the embodiments of this application further includes: an air filter 800, a third thermocouple 801, a fourth thermocouple 802 and a fifth thermocouple 803. The air filter 800 is connected to the air inlet of the first induced draft fan 703, the third thermocouple 801 is located at the air outlet of the first induced draft fan 703, the fourth thermocouple 802 is located on the support base 105, and the fifth thermocouple 803 is located in the cooling chamber 103.

[0155] In one embodiment, the first induced draft fan 703 is equipped with a G4-grade air filter 800 at its air inlet end, with a filtration efficiency of ≥90% for particles larger than 5μm, and a third thermocouple 801 with a temperature measurement range of 0-100℃ and a response time of ≤0.5s at its air outlet end; a fifth thermocouple 803 with a temperature measurement range of 0-1500℃ and a response time of ≤0.5s is installed on the left side wall of the cooling chamber 103; and a discharge port 104 with a diameter of DN200-DN250 is provided on the right side wall of the cooling chamber 103.

[0156] The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres provided in the embodiments of this application further includes: an automatic discharge device 804, a cooling tower 806, an online particle size analyzer 807, and a control unit 808. The automatic discharge device 804 is connected to the second discharge end 303, the cooling tower 806 is connected to the automatic discharge device 804, and the online particle size analyzer 807 is connected to the finished product collection end of the cooling tower 806. The online particle size analyzer 807 is used to analyze the particle size of the calcium fluoride microspheres. The control unit 808 is electrically connected to the online particle size analyzer 807 and is used to control at least one of the following actuators based on the particle size obtained by the online particle size analyzer 807: a discharge valve. Door 203, split conveyor, burner 400, first thermocouple 402, first pressure sensor 403, first induced draft fan 703, second induced draft fan 7002, first electric rhomboid valve 7003, first thermal gas mass flow meter, second thermocouple 7005, exhaust valve 7007, second electric rhomboid valve 7012, second thermal mass flow meter 7013, third electric rhomboid regulating valve, third thermal gas mass flow meter, third thermocouple 801, fourth thermocouple 802, fifth thermocouple 803, combustible gas electric rhomboid regulating valve, combustible gas thermal mass flow meter, combustion-supporting gas electric rhomboid regulating valve, combustion-supporting gas thermal mass flow meter.

[0157] Understandably, the calcium fluoride microspheres entering the automatic discharger 804 can be cooled by the cooling tower 806 and then discharged to the outside through the finished product collection end of the cooling tower 806. By setting up an online particle size analyzer 807, the particle size of the calcium fluoride microspheres at the finished product collection end can be detected to ensure product quality and system efficiency. One or more parameters such as the feeding speed, combustion zone temperature, gas flow rate, cooling chamber residence time, cooling rate, and feeding / discharging frequency of the fluidized bed reactor 100 can be adjusted to achieve intelligent control of the entire process.

[0158] In one embodiment, a pneumatic flap valve automatic discharge device 804 is connected to the second discharge end 303. Coarse calcium fluoride microspheres can be fed into the middle of a counter-current cooling tower 806 through a discharge pipe with an inner diameter of DN100-DN150. The counter-current cooling tower 806 further cools the coarse finished product separated from the fluidized bed reaction system. The online particle size analyzer 807 has a measurement range of 0.1-1500 μm and an accuracy of ±0.5%. The control component 808 can be a distributed control system, i.e., a DCS control system. The unloading valve 203, the separate conveyor, the burner 400, the first thermocouple 402, the first pressure sensor 403, the first induced draft fan 703, the second induced draft fan 7002, the first electric rhomboid valve 7003, the first thermal gas mass flow meter, the second thermocouple 7005, the exhaust valve 7007, the second electric rhomboid valve 7012, the second thermal mass flow meter 7013, the third electric rhomboid regulating valve, the third thermal gas mass flow meter, the third thermocouple 801, the fourth thermocouple 802, the fifth thermocouple 803, the combustible gas electric rhomboid regulating valve, the combustible gas thermal mass flow meter, the auxiliary gas electric rhomboid regulating valve, and the auxiliary gas thermal mass flow meter are all connected to the DCS control system.

[0159] It is understandable that, through the above implementation methods, the apparatus for preparing calcium fluoride microspheres by high-temperature fluidization can achieve intelligent control of the entire process.

[0160] like Figure 2 As shown, embodiments of this application provide a method for preparing calcium fluoride microspheres by high-temperature fluidization. The method is based on an apparatus suitable for preparing calcium fluoride microspheres by high-temperature fluidization as provided in any of the above embodiments, and includes the following steps:

[0161] S01: The calcium fluoride sludge and mineralizer in the feed assembly 200 are conveyed to the combustion chamber 101 of the fluidized bed reactor 100 through the feed inlet 102;

[0162] S02: Melt the calcium fluoride sludge and mineralizer in the combustion chamber 101;

[0163] S03: The molten calcium fluoride sludge and mineralizing agent are transported to the cooling chamber 103 to form calcium fluoride microspheres;

[0164] S04: The calcium fluoride microspheres in the cooling chamber 103 are conveyed to the cyclone separator 300 to separate the calcium fluoride microspheres into calcium fluoride microspheres of a preset particle size and calcium fluoride microspheres of a smaller particle size;

[0165] S05: Deliver small-diameter calcium fluoride microspheres to combustion chamber 101;

[0166] S06: Output calcium fluoride microspheres with a preset particle size.

[0167] Through the above implementation method, the calcium fluoride sludge and mineralizer in the feeding assembly 200 can be melted in the combustion chamber 101, recrystallized in the cooling chamber 103, and then output through the cyclone separator 300, so that the calcium fluoride sludge can form calcium fluoride microspheres. By setting the combustion chamber 101, the calcium fluoride sludge and mineralizer can be melted, and the eutectic reaction between the mineralizer and calcium fluoride can be triggered, realizing rapid melting of the particle surface and reconstruction of active sites. By setting the combustion chamber 101 above the cooling chamber 103, the molten calcium fluoride sludge and mineralizer can drip into the interior of the cooling chamber 103. During the flow process, the molten calcium fluoride droplets undergo forced convection heat exchange with the low-temperature gas, the surface temperature drops rapidly, triggering the homogeneous nucleation process of the supersaturated liquid phase, forming nanoscale initial crystal nuclei. These nanoscale primary crystal nuclei serve as active sites for the growth of calcium fluoride crystals within the cooling chamber 103. Based on the Ostwald ripening mechanism, nanoscale primary crystal nuclei continuously capture surrounding molten calcium fluoride molecules through surface adsorption and diffusion. In the unique turbulent flow field of the fluidized bed reactor 100, particle collisions occur frequently, promoting the uniform spreading and epitaxial growth of molten droplets on the surface of the crystal nuclei, enabling the crystals to preferentially grow along the crystal planes, ultimately forming large-diameter regular crystals.

[0168] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0169] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0170] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on something” but also “on something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0171] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90° or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0172] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres, characterized in that, include: A fluidized bed reactor (100) has a combustion chamber (101) and a feed inlet (102) communicating with the combustion chamber (101), a cooling chamber (103) communicating with the combustion chamber (101) and a discharge outlet (104) communicating with the cooling chamber (103). Along the height direction of the fluidized bed reactor (100), the combustion chamber (101) is located above the cooling chamber (103). The feeding assembly (200) is connected to the combustion chamber (101) through the feed inlet (102). The feeding assembly (200) is used to mix calcium fluoride sludge and mineralizer, wherein the active component in the mineralizer is Al. 3+ Or Si 4+ ; Cyclone separator (300) has a feed end (301), a first discharge end (302) and a second discharge end (303) connected together. The feed end (301) is connected to the discharge port (104). The first discharge end (302) is connected to the first gas distribution plate (404) in the combustion chamber (101). The second discharge end (303) is used to output calcium fluoride microspheres.

2. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to claim 1, characterized in that, The feeding assembly (200) includes: A mixer (201) has a mixing chamber and a feeding port and a discharging port communicating with the mixing chamber. The feeding port is used to feed the calcium fluoride sludge and the mineralizing agent into the mixing chamber. Feed pipe (202), one end of which is connected to the discharge port, and the other end of which is connected to the feed port (102); A discharge valve (203) is connected to the feed pipe (202); A powder conveying component (204) is connected to the feed pipe (202). Along the length of the feed pipe (202), the powder conveying component (204) is located at the end of the discharge valve (203) away from the mixer (201).

3. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to claim 1, characterized in that, Also includes: A burner (400) is provided in the fluidized bed reactor (100), and the ignition end of the burner (400) is located in the combustion chamber (101); A gas distributor (401) is provided in the fluidized bed reactor (100), and the gas distributor (401) is used to deliver combustible gas and combustion-supporting gas toward the combustion chamber (101); A first thermocouple (402) is disposed in the combustion chamber (101), and the first thermocouple (402) is used to measure the internal temperature of the combustion chamber (101); A first pressure sensor (403) is disposed in the combustion chamber (101), and the first pressure sensor (403) is used to measure the internal pressure of the combustion chamber (101); A first gas distribution plate (404) is disposed in the combustion chamber (101) and is used to deliver airflow toward the combustion chamber (101).

4. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to any one of claims 1-3, characterized in that, Also includes: A flow guiding assembly (500) is disposed in the combustion chamber (101), and the flow guiding assembly (500) connects the combustion chamber (101) and the cooling chamber (103). The flow guiding component (500) includes: A flow guide (501), the outer ring of which is detachably connected to the inner wall of the fluidized bed reactor (100); An atomizing nozzle (502) is connected to the flow guide (501) and the atomizing nozzle (502) is located inside the cooling chamber (103).

5. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to claim 4, characterized in that, Also includes: A cylindrical dividing member (600) is disposed in the cooling cavity (103) and connected to the flow guide (501). The cylindrical dividing member (600) has an inner cavity and a through hole communicating with the inner cavity. The inner cavity is connected to the cooling cavity (103) through the through hole. A second gas distribution plate (601) is disposed in the inner cavity, and the second gas distribution plate (601) is used to deliver cooling airflow toward the inner cavity; The third gas distribution plate (602) is disposed in the cooling chamber (103) along the height direction of the fluidized bed reactor (100). The third gas distribution plate (602) is spaced below the second gas distribution plate (601) and is used to deliver cooling airflow toward the cooling chamber (103).

6. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to claim 5, characterized in that, Also includes: A first gas conveying assembly (700) is connected at one end to the first discharge end (302) and at the other end to the first gas distribution plate (404). The first gas conveying assembly (700) is used to convey the gas flow from the first discharge end (302) to the first gas distribution plate (404). The second gas delivery assembly (701) is connected to the second gas distribution plate (601) and is used to deliver the cooling gas flow to the second gas distribution plate (601). A third gas delivery assembly (702) is connected to the third gas distribution plate (602). The third gas delivery assembly (702) is used to deliver the cooling airflow to the third gas distribution plate (602). The third gas delivery assembly (702) and the second gas delivery assembly (701) are connected in parallel. The first induced draft fan (703) is connected to the second gas delivery assembly (701) and the third gas delivery assembly (702), respectively; A cooling coil (704) is arranged around the outside of the third gas delivery assembly (702) for cooling the third gas delivery assembly (702).

7. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to claim 6, characterized in that, The first gas delivery assembly (700) includes: The first conveying component (7001) has one end connected to the first gas distribution plate (404) and the other end connected to the first discharge end (302). The second induced draft fan (7002) is connected to the first conveyor (7001); The first electric rhomboid valve (7003) is connected to the first conveying member (7001). A first thermal mass flow meter (7004) is connected to the first conveying member (7001). The second thermocouple (7005) is disposed on the first conveying member (7001). Along the length direction of the first conveying member (7001), the second induced draft fan (7002), the first electric diamond valve (7003), the first thermal mass flow meter (7004) and the second thermocouple (7005) are arranged in sequence at intervals. An exhaust pipe (7006) is connected to the first conveying member (7001) along the length of the first conveying member (7001), and the exhaust pipe (7006) is located between the second induced draft fan (7002) and the first electric diamond valve (7003). An exhaust valve (7007) is provided on the exhaust pipe (7006).

8. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to claim 6, characterized in that, The second gas delivery assembly (701) includes: The second conveying component (7011) has one end connected to the second gas distribution plate (601) and the other end connected to the first induced draft fan (703). The second electric diamond valve (7012) is connected to the second conveying member (7011); The second thermal mass flow meter (7013) is connected to the second conveying member (7011).

9. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to claim 8, characterized in that, The fluidized bed reactor (100) has a support base (105), the cooling coil (704) is arranged in a ring around the support base (105), and the third gas delivery assembly (702) passes through the support base (105). The third gas delivery assembly (702) includes: The third conveying component (7021) has one end connected to the third gas distribution plate (602) and the other end connected to the first induced draft fan (703). The third electric diamond valve (7022) is connected to the third conveying component (7021); The third thermal mass flow meter (7023) is connected to the third conveying component (7021).

10. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to claim 9, characterized in that, Also includes: An air filter (800) is connected to the air inlet of the first induced draft fan (703); The third thermocouple (801) is located at the outlet end of the first induced draft fan (703); The fourth thermocouple (802) is provided on the support base (105); The fifth thermocouple (803) is located in the cooling chamber (103).

11. The apparatus for high-temperature fluidized bed preparation of calcium fluoride microspheres according to any one of claims 1-3, characterized in that, Also includes: An automatic feeder (804) is connected to the second discharge end (303); Cooling tower (806) is connected to the automatic discharger (804); An online particle size analyzer (807) is connected to the finished product collection end of the cooling tower (806), and the online particle size analyzer (807) is used to analyze the particle size of the calcium fluoride microspheres; A control unit (808) is electrically connected to the online particle size analyzer (807). The control unit (808) is used to control at least one of the following actuators based on the particle size obtained by the online particle size analyzer (807): unloading valve (203), split conveyor, burner (400), first thermocouple (402), first pressure sensor (403), first induced draft fan (703), second induced draft fan (7002), first electric rhomboid valve (7003), first thermal gas mass flow meter, second thermocouple (7005), exhaust valve (7007), second electric rhomboid valve (7012), second thermal mass flow meter (7013), third electric rhomboid regulating valve, third thermal gas mass flow meter, third thermocouple (801), fourth thermocouple (802), fifth thermocouple (803), combustible gas electric rhomboid regulating valve, combustible gas thermal mass flow meter, combustion-supporting gas electric rhomboid regulating valve, and combustion-supporting gas thermal mass flow meter.

12. A method for preparing calcium fluoride microspheres by high-temperature fluidization, characterized in that, The method is based on the apparatus for preparing calcium fluoride microspheres by high-temperature fluidization as described in any one of claims 1-11, and the method includes the following steps: The calcium fluoride sludge and mineralizer in the feed assembly (200) are conveyed to the combustion chamber (101) of the fluidized bed reactor (100) through the feed inlet (102). The calcium fluoride sludge and the mineralizing agent in the combustion chamber (101) are melted; The molten calcium fluoride sludge and the mineralizing agent are transported to the cooling chamber (103) to form calcium fluoride microspheres; The calcium fluoride microspheres in the cooling chamber (103) are conveyed to the cyclone separator (300) to separate the calcium fluoride microspheres into calcium fluoride microspheres of a preset particle size and calcium fluoride microspheres of a smaller particle size; The small-diameter calcium fluoride microspheres are delivered to the combustion chamber (101). The calcium fluoride microspheres with the preset particle size are output.

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