An integrated device and method for fluorine recovery and gypsum crystal reconstruction in wet production

Abstract

The present invention discloses an integrated device and method for fluorine recovery and gypsum crystal reconstruction in wet production. The device includes an integrated absorption unit, a mounting frame, and a tilting reaction furnace tube. The tilting reaction furnace tube includes a reaction section. A protruding member for suppressing tangential flow is provided in the reaction section. A rotary drive assembly drives the tilting reaction furnace tube to rotate, and an inclination adjustment mechanism is used to adjust the inclination angle of the tilting reaction furnace tube. The present invention achieves a seamless connection between the reaction and crystallization processes by integrating the acidolysis reaction and crystal reconstruction functions in the same device. The device adopts a tilting reaction furnace tube design, combined with an adjustable inclination mechanism, to flexibly adjust the inclination angle of the reaction furnace tube during the acidolysis reaction and crystal reconstruction stages, thereby shortening the acidolysis time, reducing heat loss, and improving reaction efficiency and product quality.

Description

Technical Field

[0001] The present invention belongs to the field of wet-process phosphoric acid preparation, and relates to an integrated device and method for fluorine recovery and gypsum crystal reconstruction in wet-process production, and in particular to a new process for wet-process phosphoric acid processing that can efficiently recover fluorine resources and achieve gypsum crystal reconstruction. Background Art

[0002] In the field of wet-process phosphoric acid production, the effective recovery of fluorine resources and the crystal reconstruction of phosphogypsum have always been key industry concerns. While the traditional wet-process phosphoric acid process has achieved some success in fluorine recovery and phosphogypsum treatment, it still has many shortcomings and urgently needs improvement.

[0003] Existing wet-process phosphoric acid production processes typically utilize fixed reaction units for separate acidolysis and crystal reconstruction. This separate unit design not only occupies a large footprint but also results in heat loss during material transfer, reducing energy efficiency. Furthermore, conventional reaction units typically utilize a single agitator for mixing. This mixing method often struggles to achieve adequate mixing for highly viscous reaction materials, impacting reaction efficiency and product quality.

[0004] Prior research results, CN118877896A, proposed a new wet phosphoric acid processing process for fluorine recovery. Through acid hydrolysis and crystal reconstruction steps, it achieved efficient fluorine recovery and improved phosphogypsum quality for the first time. However, as research on this technology continued to deepen, the inventors discovered that this process still has some limitations in practical application:

[0005] 1. Acid hydrolysis reaction and crystal reconstruction are carried out in different equipment, resulting in low equipment utilization and complex operation;

[0006] 2. There is a risk of secondary fluorine contamination during the acidolysis reaction to crystal reconstruction process, with about 2% to 3% of fluorine-containing gas escaping;

[0007] 3. During the acid hydrolysis and crystal reconstruction process, the control of temperature and material flow is not precise enough, which limits the improvement of the crystal quality and purity of phosphogypsum;

[0008] 4. The particle size of the product reconstructed in the constant temperature bath needs to be further improved;

[0009] 5. The fineness of the mineral powder is very demanding: it needs to be above 200 mesh, and the grinding energy consumption is high. Summary of the Invention

[0010] In response to the above problems, the present invention proposes an integrated device and method for fluorine recovery and gypsum crystal reconstruction in wet production. Through device-process collaborative innovation, it solves the problems of high energy consumption, fluorine leakage and low gypsum quality caused by equipment separation in the original patent, and realizes efficient recovery of fluorine resources and high-value utilization of phosphogypsum.

[0011] The integrated device and method of the present invention solve the problems of low equipment utilization, complex operation, insufficient material mixing, large heat loss, etc. in the prior art by optimizing the device structure and process flow, thereby achieving efficient recovery of fluorine resources and high-quality crystal reconstruction of phosphogypsum, reducing production costs, and improving production efficiency and product quality.

[0012] Through long-term exploration and experimentation, as well as numerous experiments and efforts, the inventors have continuously innovated and reformed to solve the above technical problems. The present invention provides a technical solution that provides an integrated device for fluorine recovery and gypsum crystal reconstruction in wet production, comprising an integrated absorption unit, a multi-purpose tube having a first end connected to a reaction section, a second end connected to an absorption bottle, and a vacuum pump connected thereto, and further comprising:

[0013] The mounting frame is provided with a mounting shaft, on which a yoke and a support bearing are mounted; the yoke includes a first sleeve and a second sleeve, the axis lines of which are perpendicular to each other; the first sleeve is rotatably engaged with the mounting shaft; the support bearing and the end of the first support section constitute a high-amplitude mechanism;

[0014] The tilting reactor tube includes a first support section, a reaction section, and a second support section in the axial direction. The inner wall of the reaction section is sprayed with a polytetrafluoroethylene coating and is provided with a protruding member to suppress tangential flow. The tail of the first support section is provided with a tail shaft and a third bevel gear. The tail shaft is rotatably engaged with the second sleeve.

[0015] A rotation drive assembly drives the tilting reaction furnace tube to rotate by engaging the first bevel gear and the second bevel gear with the third bevel gear;

[0016] The tilt angle adjustment mechanism includes a lifting adjustment unit and a supporting wheel group, which is used to adjust the tilt angle of the tilting reaction furnace tube to 30°~60°; the supporting wheel group and the outer wall of the tilting reaction furnace tube form a height mechanism.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention integrates the acidolysis reaction and crystal reconstitution functions into a single device, achieving a seamless transition between the reaction and crystallization processes. The device utilizes a tilting reactor tube design with an adjustable tilt mechanism, allowing for flexible adjustment of the reactor tube's tilt angle during the acidolysis and crystal reconstitution phases. This optimizes reaction conditions, reduces heat loss, and improves reaction efficiency and product quality.

[0019] On the basis of the above technical solution, the present invention can also be improved as follows:

[0020] Furthermore: the protruding components are hemispherical, prismatic or trapezoidal, and are evenly distributed on the inner wall of the reaction chamber to enhance the axial flow and radial flow.

[0021] Compared with the prior art, the beneficial effects of adopting the above further technical solution are:

[0022] The present invention further optimizes the fluid flow pattern in the reaction chamber by designing the protruding members into a hemispherical, prismatic or trapezoidal shape and evenly distributing them on the inner wall of the reaction chamber, significantly enhancing the axial flow and radial flow, thereby improving the mass transfer efficiency and reaction rate, and ensuring the high efficiency of the fluorine recovery and gypsum crystal reconstruction processes.

[0023] On the basis of the above technical solution, the present invention can also be improved as follows:

[0024] Furthermore, the tilting reaction furnace tube is at an angle of 0° and a rotation speed of 500-1000 rpm in the acidolysis mode; and is adjusted to 35°-55° and a rotation speed of 100-500 rpm in the crystal reconstruction mode.

[0025] Compared with the prior art, the beneficial effects of adopting the above further technical solution are:

[0026] Horizontal high-speed rotation (0° / 500~1000rpm) during the acid hydrolysis stage ensures the completeness of the reaction, while inclined low-speed rotation (35°~55° / 100~500rpm) during the crystal reconstruction stage synergistically controls the crystal growth direction and temperature gradient, thereby increasing the purity of α-hemihydrate gypsum to ≥98.5%, increasing the crystal size to 100~500μm, and improving the filtration efficiency.

[0027] On the basis of the above technical solution, the present invention can also be improved as follows:

[0028] Furthermore: the lifting adjustment unit of the tilt adjustment mechanism is a hydraulic lifting assembly, a screw lifting assembly or a multi-stage sleeve lifting assembly.

[0029] Compared with the prior art, the beneficial effects of adopting the above further technical solution are:

[0030] The present invention adopts hydraulic lifting components, screw lifting components or multi-stage sleeve lifting components as lifting and adjusting units, providing multiple efficient and stable implementation methods for adjusting the angle of the tilting reaction furnace tube. These components can not only accurately control the inclination angle of the furnace tube to meet the different process requirements of acid hydrolysis and crystal reconstruction, but also ensure the stability and reliability of the device operation, extend the service life of the equipment, and at the same time improve the flexibility and automation level of operation.

[0031] On the basis of the above technical solution, the present invention can also be improved as follows:

[0032] Furthermore: a detachable graphene-fluorinated resin composite baffle is provided between the reaction section and the first support section; a polytetrafluoroethylene plug with a hole is installed at the connecting end of the reaction section and the second support section.

[0033] Compared with the prior art, the beneficial effects of adopting the above further technical solution are:

[0034] The graphene-fluorinated resin composite baffle not only effectively prevents fluoride leakage and corrosion, but its removable design also facilitates cleaning of the reaction chamber and slurry discharge, reducing maintenance time and costs. A perforated polytetrafluoroethylene plug further enhances the device's sealing and corrosion resistance, while allowing gas to escape, ensuring stable pressure during the reaction and improving operational safety and reliability. These improvements effectively enhance the stability and durability of the device during the acidolysis reaction and crystal reconstruction process, extending the equipment's service life while also improving fluorine recovery and the efficiency of gypsum crystal reconstruction.

[0035] On the basis of the above technical solution, the present invention can also be improved as follows:

[0036] Furthermore: the first bevel gear is in transmission connection with a pulley transmission mechanism, and the pulley transmission mechanism is in transmission connection with a power input device.

[0037] Compared with the prior art, the beneficial effects of adopting the above further technical solution are:

[0038] The present invention realizes smooth and efficient transmission of power, enables the tilting reaction furnace tube to rotate accurately and stably, thereby improving the mixing uniformity and reaction efficiency of the reaction materials, and at the same time simplifies the transmission structure and facilitates maintenance and adjustment.

[0039] On the basis of the above technical solution, the present invention can also be improved as follows:

[0040] Furthermore: the multi-purpose pipe is detachable or connected to the material supply unit and the integrated absorption unit through a multi-way valve.

[0041] Compared with the prior art, the beneficial effects of adopting the above further technical solution are:

[0042] This invention significantly enhances the operational flexibility and convenience of the device. This connection method allows for rapid switching between material supply and gas absorption functions during different production stages, reducing production interruptions caused by switching operations, improving production efficiency, and reducing maintenance costs. Furthermore, the use of a multi-way valve effectively prevents cross-contamination between different materials, ensuring production process safety and stable product quality.

[0043] The present invention also provides a method for wet processing phosphoric acid based on the above-mentioned device, comprising the following steps:

[0044] a) Acid hydrolysis reaction: Fluorapatite ore powder with a moisture content of ≤28% and a particle size of 100 mesh is placed in a tilting reactor tube with excess concentrated sulfuric acid. The reaction is carried out at 120-160°C and 500-1000 rpm for 2-4 hours. The escaping fluorine-containing gas is recovered through an integrated absorption unit;

[0045] b) Crystal reconstruction: Tilt the reactor tube to 30°-60° using the tilt adjustment mechanism, add water to adjust the liquid-to-solid ratio to 2.5-4:1, and react at 110-120°C and 100-500 rpm for 3-4 hours to convert anhydrous calcium sulfate into α-calcium sulfate hemihydrate. The escaping fluorine-containing gas is recovered via an integrated absorption unit.

[0046] c) Filtration and washing: Separate the phosphoric acid filtrate and the calcium sulfate hemihydrate filter cake, and wash the filter cake in countercurrent.

[0047] Compared with the prior art, the beneficial effects of adopting the above further technical solution are:

[0048] Through the coordinated optimization of the integrated acid hydrolysis-crystal reconstruction process, the fluorine recovery rate, gypsum quality and energy efficiency are comprehensively improved:

[0049] During the acidolysis stage, high temperature and high speed drive the slurry P2O5 concentration to ≥55%. Combined with continuous gas absorption, the total fluorine escape rate reaches 99.21%. During the crystal reconstruction stage, the residual fluorine is absorbed twice, and the fluorine soluble in phosphoric acid is reduced to ≤101ppm.

[0050] The tilted reactor forms a temperature gradient, which, in conjunction with low-speed rotation, suppresses crystal breakage, resulting in α-hemihydrate gypsum with a purity of ≥98.5% and a size of 100-500 μm, resulting in higher filtration efficiency.

[0051] The slurry transfer process is eliminated, and the residual heat from acid decomposition is directly used to maintain the crystal reconstruction temperature. The particle size requirement of the mineral powder is relaxed to 100 mesh, and the energy consumption and grinding costs are greatly reduced.

[0052] On the basis of the above technical solution, the present invention can also be improved as follows:

[0053] Furthermore, the water added in step b) is a gypsum wash solution, and after crystal reconstruction, the purity of α-CaSO4·0.5H2O is ≥98.5%, and the crystal size is 100-500 μm; the final phosphogypsum product has a water-soluble phosphorus content ≤800 ppm and a water-soluble fluorine content ≤200 ppm, and the phosphoric acid product has a water-soluble fluorine content ≤1000 ppm.

[0054] Compared with the prior art, the beneficial effects of adopting the above further technical solution are:

[0055] By using a gypsum wash solution for the hydration reaction during the crystal reconstruction step, the present invention not only achieves water resource recycling and reduces production costs, but also effectively improves the quality of phosphogypsum and phosphoric acid, broadens the application of phosphogypsum in building materials, medical materials, and other fields, achieves efficient recovery of fluorine resources and high-value-added utilization of phosphogypsum, further reduces environmental pollution risks, and enhances the economic and environmental benefits of the entire wet-process phosphoric acid process.

[0056] On the basis of the above technical solution, the present invention can also be improved as follows:

[0057] Furthermore, the total fluorine emission rate in steps a) and b) is as high as 99.21%. The fluorine-containing gas is absorbed using a sodium hydroxide solution, and the concentration of the sodium fluoride solution is controlled to be 10-18 wt%.

[0058] Compared with the prior art, the beneficial effects of adopting the above further technical solution are:

[0059] The present invention achieves a total fluorine release rate of up to 99.21% by optimizing the acidolysis reaction and crystal reconstruction steps. It also uses sodium hydroxide solution to absorb fluorine-containing gases and precisely controls the concentration of the sodium fluoride solution between 10 and 18 wt%. This significantly improves the recovery efficiency and purity of fluorine resources, effectively reduces fluorine resource waste and environmental pollution risks, and further enhances the economic and environmental benefits of wet-process phosphoric acid production. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0061] Figure 1 It is a front structural schematic diagram of a preferred embodiment of the integrated device for fluorine recovery and gypsum crystal reconstruction in wet production of the present invention.

[0062] Figure 2 yes Figure 1 Schematic diagram of the right view structure.

[0063] Figure 3 yes Figure 1 Schematic diagram of the left view structure.

[0064] Figure 4 yes Figure 1 Schematic diagram of the rear view structure.

[0065] Figure 5 yes Figure 1 Schematic diagram of the top view structure.

[0066] Figure 6 yes Figure 1 Schematic diagram of the three-dimensional structure.

[0067] Figure 7 It is a schematic diagram of the three-dimensional structure of the crystal reconstruction state of a preferred embodiment of the integrated device for fluorine recovery and gypsum crystal reconstruction in wet production of the present invention.

[0068] Figure 8 It is a schematic diagram of the cross-sectional structure of the tilting reaction furnace tube in a preferred embodiment of the integrated device for fluorine recovery and gypsum crystal reconstruction in wet production of the present invention.

[0069] Figure 9 It is a schematic diagram of the three-dimensional structure of the fork in a preferred embodiment of the integrated device for fluorine recovery and gypsum crystal reconstruction in wet production of the present invention.

[0070] The marks in the figure are:

[0071] 100 mounting rack,

[0072] 110 installation shaft,

[0073] 120 triangle support frame,

[0074] 130 support bearings,

[0075] 140 forks,

[0076] 141 first sleeve,

[0077] 142 second sleeve,

[0078] 200 heating components,

[0079] 300 tilting reactor tube,

[0080] 310 first support section,

[0081] 311 tail shaft,

[0082] 312 third bevel gear,

[0083] 320 reaction section,

[0084] 321 reaction chamber,

[0085] 322 PTFE plug,

[0086] 323 raised member,

[0087] 330 second support section,

[0088] 331 multi-purpose tube,

[0089] 400 rotary drive assembly,

[0090] 410 motor,

[0091] 421 first pulley,

[0092] 422 transmission belt,

[0093] 423 second pulley,

[0094] 431 first bevel gear,

[0095] 432 second bevel gear,

[0096] 500° tilt adjustment mechanism,

[0097] 510 lifting adjustment unit,

[0098] 520 support wheels. DETAILED DESCRIPTION

[0099] The following describes a specific embodiment with reference to the accompanying drawings.

[0100] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention.

[0101] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it may not be further defined or explained in subsequent drawings.

[0102] Example 1

[0103] See also Figures 1 to 9 The integrated device for fluorine recovery and gypsum crystal reconstruction in wet production described in this embodiment is composed of a mounting frame 100 , a heating assembly 200 , a tilting reaction furnace tube 300 , a rotary drive assembly 400 , and an inclination adjustment mechanism 500 .

[0104] The mounting frame 100 serves as the supporting foundation for the entire device. It has anchor bolt holes at the bottom for securing it to the foundation to ensure operational stability. The heating assembly 200 provides heat for the acidolysis reaction, especially during the initial stages, ensuring a stable reaction temperature. The tilting reactor tube 300 is the only location for the acidolysis reaction and crystal reconstruction. The rotary drive assembly 400 provides the rotary drive force to achieve material mixing and mass transfer. The tilt adjustment mechanism 500 is responsible for adjusting the tilt angle of the tilting reactor tube 300.

[0105] Specifically, in this embodiment, the specific structure and reference parameters of the mounting frame 100 and its related components are as follows:

[0106] The mounting frame 100 is made of 2205 steel and measures 3000 mm long, 2000 mm wide, and 1500 mm high. It has a rectangular frame structure and is painted for corrosion protection. Depending on the application, the length of the mounting frame 100 can be adjusted between 500 and 5000 mm. Anchor bolt holes are provided at the bottom of the mounting frame 100 for securing the entire device to a foundation, ensuring stability during operation. The frame design evenly distributes the weight and forces of the entire device, ensuring safety and stability during operation.

[0107] Mounting shaft 110 is mounted at the top of mounting frame 100. Made of 45-gauge steel, it has a diameter of 120 mm and a length of 2000 mm. Four high-strength bolts secure the shaft to the mounting frame, ensuring stability when carrying and transmitting torque. A yoke 140 is mounted in the middle of shaft 110; support bearings 130 are mounted on either side of yoke 140.

[0108] When the mounting shaft 110 bears a heavy load, a triangular support frame 120 is installed. Made of 10mm-thick Q235 steel plate and shaped like a triangle, triangular support frame 120 is located below yoke 140. The base of triangular support frame 120 is welded to the bottom of mounting frame 100, and its apex is connected to the middle of mounting shaft 110. The design of triangular support frame 120 effectively enhances the load-bearing capacity and bending stiffness of mounting shaft 110, preventing vibration and deformation caused by an excessively long mounting shaft and ensuring stable operation of the device.

[0109] The support bearings 130 are spherical roller bearings. Installed on either side of the yoke 140 on the mounting shaft 110, they support the rotation of the tilting reactor tube 300, reduce the load between the tilting reactor tube 300 and the bevel gear assembly, and reduce friction between the yoke 140 and the mounting shaft 110. The spherical roller bearings automatically adapt to slight shaft bending and installation errors, ensuring reliable operation of the device.

[0110] See also Figure 9 The yoke 140 is composed of a first sleeve 141 and a second sleeve 142, and the axis lines of the first sleeve 141 and the second sleeve 142 are perpendicular to each other. The first sleeve 141 is mounted on the mounting shaft 110 and can rotate around the mounting shaft. The second sleeve 142 is used to connect the tail shaft 311 of the tilting reactor tube 300 and rotate with the tail shaft 311. A bearing is also installed between the second sleeve 142 and the tail shaft 311 to ensure smooth rotation of the tilting reactor tube 300. The two sleeves of the yoke 140 cooperate with the mounting shaft and the tail shaft 311 respectively to realize the rotation and inclination adjustment functions of the tilting reactor tube 300. The structural design of the yoke enables the reactor tube to remain stable during rotation and tilting, avoiding equipment failures caused by interference from moving parts.

[0111] In a preferred embodiment of the present invention, the heating component 200 can be heated by electricity or by a heat carrier. This embodiment introduces the electric heating method, and its main components and features are as follows:

[0112] Heating Box Furnace: Utilizing resistance wire heating elements, installed on the exterior of the tilting reactor tube 300, these elements are evenly distributed around the circumference, ensuring even heat transfer to all locations within the tube. The heating box furnace's outer shell is constructed of stainless steel, offering excellent heat and corrosion resistance. The interior is filled with insulation to minimize heat loss and improve thermal efficiency.

[0113] Resistance Wire Heating Element: High-temperature alloy resistance wire is selected, featuring high resistivity, a high melting point, and excellent oxidation resistance. The resistance wire is wound into a spiral and installed inside the heating box furnace, generating heat through the thermal effect of the current. The power of the resistance wire is designed based on the size of the reactor tube and process requirements to ensure it provides sufficient heat to maintain the required reaction temperature.

[0114] Temperature sensor: Installed inside the heating box furnace, it monitors the temperature of the heating element in real time. Thermocouples are used as temperature sensors, offering fast response, high accuracy, and high-temperature resistance. The temperature sensor is connected to the temperature control system to precisely control the heating process.

[0115] Temperature control system: Consists of a temperature controller, power regulator, and electrical control system. The temperature controller compares the real-time temperature signal fed back by the temperature sensor with the set temperature and adjusts the power regulator's output using a PID control algorithm to achieve precise control of heating power. The electrical control system is responsible for turning the heating element on and off, ensuring the safety and stability of the heating process.

[0116] In a preferred embodiment of the present invention, the tilting reactor tube 300 is the core component of the integrated device for fluorine recovery and gypsum crystal reconstruction in wet process production. Figure 8The tilting reactor tube 300 consists of a first support section 310, a reaction section 320, and a second support section 330, connected axially. Flanges are used to seal the entire tube, ensuring a tight seal during operation and preventing gas leakage and material loss. The reactor tube is made of 2205 steel, which offers excellent strength and corrosion resistance, making it suitable for the harsh chemical environment of wet-process phosphoric acid production.

[0117] The first support section 310 includes a tail shaft 311 and a third bevel gear 312 .

[0118] The tail shaft 311 is coaxially arranged with the first support section 310 and rotatably engages with the second sleeve 142 of the yoke 140, enabling the tilting reactor tube 300 to rotate within the constraints of the second sleeve 142. The tail shaft 311 and yoke 140 are connected via a bearing. The tail shaft 311 tightly fits the inner ring of the bearing, while the yoke 140 tightly fits the outer ring of the bearing, ensuring a consistent distance between the tilting reactor tube 300 and the mounting shaft 110.

[0119] The third bevel gear 312 is mounted on the end of the tail shaft 311 and meshes with the first bevel gear 431 and the second bevel gear 432 of the rotation drive assembly 400 to form a part of the gear transmission system, thereby achieving rotational drive of the tilting reactor tube 300.

[0120] A detachable graphene-fluorinated resin composite baffle is provided between the reaction section 320 and the first support section 310. The baffle can effectively prevent the leakage of corrosive gases and materials during the reaction process, and is easy to disassemble and clean, thereby reducing maintenance time and cost.

[0121] Reaction section 320 houses a reaction chamber 321, the core area where the acidolysis reaction and crystal reconstruction occur. Its inner walls are coated with a uniform polytetrafluoroethylene coating, effectively resisting corrosion from corrosive substances such as high-concentration sulfuric acid, hydrogen fluoride, and silicon tetrafluoride, ensuring long-term, stable operation of the equipment. In one embodiment, the reaction chamber measures 2000 mm in length and 600 mm in inner diameter.

[0122] The polytetrafluoroethylene plug 322 is installed at the connection end between the reaction section 320 and the second support section 330. It is made of polytetrafluoroethylene and has good chemical stability and sealing properties. It can prevent the leakage of gas and materials during the reaction process, facilitate the disassembly and installation of the multi-purpose tube 331, and facilitate the maintenance and cleaning of the equipment.

[0123] Raised members 323 are evenly distributed along the inner wall of reaction chamber 321. In one embodiment, raised members 323 are ladder-shaped, 10 mm in height, and 20 mm apart. These raised members effectively disrupt the laminar flow substratum of the fluid, inhibiting the formation of tangential flow, thereby enhancing axial and radial flow, optimizing the flow pattern of the reaction slurry, improving mass transfer and mixing efficiency, and increasing reaction efficiency and fluorine escape rate.

[0124] The second support section 330 includes a multi-purpose tube 331. The multi-purpose tube 331 is coaxially arranged with the tilting reactor tube 300. Its inner end passes through the second support section 330 and the polytetrafluoroethylene plug 322, connecting to the reaction section 320. During the rotation of the tilting reactor tube 300, the multi-purpose tube 331 can maintain synchronous rotation by connecting to a rotary joint on the outside. Alternatively, the multi-purpose tube 331 can be kept stationary by installing a sealed bearing between the polytetrafluoroethylene plug 322 and the multi-purpose tube 331. The outer end of the multi-purpose tube can be detachably connected to a material supply unit and an integrated absorption unit, depending on the production process requirements. The material supply unit includes a water supply unit. This design allows the reactor tube to quickly switch functions during different process stages, improving production efficiency and reducing maintenance costs.

[0125] One end of the multipurpose tube 331 is connected to the reaction chamber 321, and the other end is connected to an absorption bottle (not shown). The absorption bottle contains sodium hydroxide solution, which absorbs the escaping fluorine-containing gas. The absorption bottle is connected to a vacuum pump, which uses negative pressure to guide the fluorine-containing gas into the absorption bottle, achieving effective fluorine resource recovery.

[0126] In a preferred embodiment of the present invention, the rotation drive assembly 400 is responsible for driving the rotation of the tilting reactor tube 300 .

[0127] The motor 410 is mounted on the mounting frame 100 and fixed by bolts to ensure stability during operation. The output shaft of the motor is connected to the first pulley 421 to provide power for the entire rotary drive system.

[0128] The first pulley 421 is mounted on the output shaft of the motor 410. The transmission belt 422 is a V-belt with high tensile strength and good elasticity, which can effectively transmit power and reduce slippage during transmission. The second pulley 423 is mounted on the mounting shaft 110. The first bevel gear 431 is mounted on the other side of the second pulley 423 and rotates coaxially and synchronously with the second pulley 423, serving as the active bevel gear. The second bevel gear 432 is mounted on the mounting shaft 110 and forms a symmetrical gear set with the first bevel gear 431. The third bevel gear 312 is located between the first bevel gear 431 and the second bevel gear 432, and meshes with both.

[0129] Motor 410 smoothly transmits power to the bevel gear set through a combination of a pulley and a transmission belt. Belt drive provides a buffering and vibration-absorbing feature, reducing the impact load during motor startup and extending the life of the equipment.

[0130] The bevel gear set is designed to change the direction of rotation by 90 degrees, simultaneously adjusting speed and torque. The meshing of the first bevel gear 431 and the second bevel gear 432 transmits torque to the third bevel gear 312 of the first support section 310 of the tilting reactor tube 300, driving the tube's rotation. The high-precision machining of the bevel gears ensures smooth and accurate transmission.

[0131] By selecting pulleys with different diameters and bevel gears with different numbers of teeth, the rotational speed and torque output of the tilting reactor tube 300 can be flexibly adjusted to meet different process requirements.

[0132] All components are made of existing high-strength materials and are precision machined and heat-treated, ensuring the reliability and durability of the rotary drive components in harsh working environments.

[0133] In a preferred embodiment, a gearbox is further installed between the motor 410 and the first pulley 421. A planetary gearbox is recommended for the gearbox, and the speed ratio range is preferably 0.5-2.0.

[0134] The tilt angle adjustment mechanism 500 is used to adjust the tilt angle of the tilting reaction furnace tube 300 .

[0135] In a preferred embodiment of the present invention, the lifting and adjustment unit 510 utilizes a hydraulic lifting mechanism consisting of a hydraulic pump station, a hydraulic cylinder, and a control system. The hydraulic pump station provides a high-pressure oil source, driving the hydraulic cylinder to extend and retract, thereby driving the support wheel assembly 520 up and down. This hydraulic lifting mechanism offers strong load-bearing capacity, smooth lifting, and precise positioning. It can precisely adjust the tilt angle of the tilting reactor tube 300 to a range of 30° to 60° according to process requirements. The control system utilizes a PLC, enabling automated operation and improving production efficiency and safety.

[0136] The support wheel assembly 520 is mounted atop the lifting and adjusting unit 510 and consists of two high-strength, wear-resistant support wheels, one located on each side of the vertically opposite sides of the tilting reactor tube 300. The support wheel assembly 520 contacts the outer wall of the tilting reactor tube 300 and forms a high-amplitude mechanism, ensuring stable support during the tilting process, preventing tube sway and displacement, and ensuring safety and stability during the production process. The support wheel assembly 520 is designed to accommodate reactor tubes of varying diameters, offering excellent versatility and adjustability.

[0137] The following describes a method for producing wet-process phosphoric acid using the integrated device for fluorine recovery and gypsum crystal reconstruction in wet production in Example 1. In the following method implementation and comparative example, the raw material is 1000 kg of fluorapatite ore powder, wherein the P2O5 content is 28.78%, the fluorine content is 2.37%, the amorphous SiO2 content is 5.04%, the water content is 26%, and the D 50 The original method expanded the mesh size from 200 to 100 mesh; the sulfuric acid concentration was 98%, and the amount added was 106% of the stoichiometric amount for acid hydrolysis of phosphate rock. The acid hydrolysis reaction time was shortened from 6 hours to 2 hours. Sodium hydroxide solution was used to absorb the fluorine gas released during the acid hydrolysis process. The absorption liquid temperature was strictly controlled at 50°C to 55°C, and the absorption system maintained a vacuum of approximately 90kPa.

[0138] During the acid hydrolysis step, the tilting reactor tube 300 is kept horizontal (0°) and rotated at 750 rpm to ensure thorough mixing and reaction between the fluorapatite ore powder and the concentrated sulfuric acid, thereby increasing the fluorine release rate. During the crystal reconstruction step, the tilting mechanism 500 adjusts the tilting angle of the tilting reactor tube 300 to 45° and reduces the rotation speed to 200 rpm to promote the conversion of anhydrous calcium sulfate to α-calcium sulfate hemihydrate while minimizing excessive wear and energy consumption.

[0139] Example 2

[0140] Acid hydrolysis step: react at 140°C for 2 hours. After acid hydrolysis, the fluorine content in the slurry is 764 ppm and the P2O5 mass fraction is 59.03%.

[0141] Crystal reconstruction steps: react at 110°C for 4 hours, with a mass ratio of phosphate rock to water of 1:2 and a mass ratio of phosphate rock to sulfuric acid of 1:1.25.

[0142] Absorption step: The acid hydrolysis and crystal reconstruction process continued to absorb, the absorption liquid temperature was 50 ° C, and the fluosilicic acid concentration was 15%.

[0143] Filtration step: The filter cake was washed three times with water in countercurrent.

[0144] Final effect: The fluorine escape rate during acid hydrolysis was 95.14%, the total fluorine escape rate was 97.33%, the P2O5 mass fraction in the phosphoric acid product was 42.65%, and the water-soluble fluorine was 305 ppm; the calcium sulfate hemihydrate content in the phosphogypsum product was 96.45%, the crystal size was 100~300μm, the water-soluble phosphorus content was 625ppm, and the water-soluble fluorine content was 153ppm.

[0145] Example 3

[0146] Acid hydrolysis step: react at 150°C for 2 hours. After acid hydrolysis, the fluorine content in the slurry is 423 ppm and the P2O5 mass fraction is 60.12%.

[0147] Crystal reconstruction steps: react at 110°C for 4 hours, with a mass ratio of phosphate rock to water of 1:2.5 and a mass ratio of phosphate rock to sulfuric acid of 1:1.2.

[0148] Absorption step: The acid hydrolysis and crystal reconstruction process continued to absorb, the absorption liquid temperature was 50 ° C, and the fluosilicic acid concentration was 15%.

[0149] Filtration step: The filter cake was washed three times with water in countercurrent.

[0150] Final effect: The fluorine escape rate during acid hydrolysis was 96.28%, the total fluorine escape rate was 98.69%, the P2O5 mass fraction in the phosphoric acid product was 43.89%, and the water-soluble fluorine was 168 ppm; the calcium sulfate hemihydrate content in the phosphogypsum product was 97.16%, the crystal size was 100~300μm, the water-soluble phosphorus content was 609 ppm, and the water-soluble fluorine content was 121 ppm.

[0151] Example 4

[0152] Acid hydrolysis step: react at 160°C for 2 hours. After acid hydrolysis, the fluorine content in the slurry is 276 ppm and the P2O5 mass fraction is 61.23%.

[0153] Crystal reconstruction step: react at 110°C for 4 hours, with a mass ratio of phosphate rock to water of 1:2.25 and a mass ratio of phosphate rock to sulfuric acid of 1:1.35.

[0154] Absorption step: The acid hydrolysis and crystal reconstruction process continued to absorb, the absorption liquid temperature was 55 ° C, and the fluosilicic acid concentration was 15%.

[0155] Filtration step: The filter cake was washed three times with water in countercurrent.

[0156] Final effect: The fluorine escape rate during acid hydrolysis was 97.34%, the total fluorine escape rate was 99.21%, the P2O5 mass fraction in the phosphoric acid product was 44.74%, and the water-soluble fluorine was 101 ppm; the calcium sulfate hemihydrate content in the phosphogypsum product was 98.88%, the crystal size was 100~300μm, the water-soluble phosphorus content was 667ppm, and the water-soluble fluorine content was 126ppm.

[0157] Comparative Example

[0158] Acid hydrolysis step: react at 150°C for 2 hours. After acid hydrolysis, the fluorine content in the slurry is 1.38%, and the P2O5 mass fraction is 55.65%.

[0159] Absorption step: Only the acid hydrolysis process is used for absorption, the absorption liquid temperature is 50°C, and the fluosilicic acid concentration is 15%.

[0160] Crystal reconstruction in a constant temperature bath: react at 110°C for 4 hours, with a mass ratio of phosphate rock to water of 1:2.25 and a mass ratio of phosphate rock to sulfuric acid of 1:1.35.

[0161] Filtration step: The filter cake was washed three times with water in countercurrent.

[0162] Final effect: The fluorine escape rate during the acidolysis process was 68.45%, the total fluorine escape rate was 68.45%, the P2O5 mass fraction in the phosphoric acid product was 42.57%, and the water-soluble fluorine was 1165 ppm; the calcium sulfate hemihydrate content in the phosphogypsum product was 95.23%, the crystal size was about 50 μm, the water-soluble phosphorus content was 1064 ppm, and the water-soluble fluorine content was 348 ppm.

[0163] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0164] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0165] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0166] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0167] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An integrated device for fluorine recovery and gypsum crystal reconstruction in wet production, comprising an integrated absorption unit, a multi-purpose tube having a first end connected to a reaction section, a second end connected to an absorption bottle, and a vacuum pump connected to the absorption bottle, characterized in that: Also includes: The mounting frame is provided with a mounting shaft, on which a yoke and a support bearing are mounted; the yoke includes a first sleeve and a second sleeve, the axis lines of which are perpendicular to each other; the first sleeve is rotatably engaged with the mounting shaft; the support bearing and the end of the first support section constitute a high-amplitude mechanism; The tilting reactor tube includes a first support section, a reaction section, and a second support section in the axial direction. The inner wall of the reaction section is sprayed with a polytetrafluoroethylene coating and is provided with a protruding member to suppress tangential flow. The tail of the first support section is provided with a tail shaft and a third bevel gear. The tail shaft is rotatably engaged with the second sleeve. A rotation drive assembly drives the tilting reaction furnace tube to rotate by engaging the first bevel gear and the second bevel gear with the third bevel gear; The tilt angle adjustment mechanism includes a lifting adjustment unit and a supporting wheel group, which is used to adjust the tilt angle of the tilting reaction furnace tube to 30°~60°; the supporting wheel group and the outer wall of the tilting reaction furnace tube form a height mechanism.

2. The device according to claim 1, characterized in that The protruding components are in the shape of a hemisphere, a prism or a trapezoid, and are evenly distributed on the inner wall of the reaction chamber to enhance the axial flow and the radial flow.

3. The device according to claim 1, characterized in that The tilting reaction furnace tube is at an angle of 0° and a rotation speed of 500-1000 rpm in the acidolysis mode; and is adjusted to 35°-55° and a rotation speed of 100-500 rpm in the crystal reconstruction mode.

4. The device according to claim 1, characterized in that The lifting adjustment unit of the tilt adjustment mechanism is a hydraulic lifting assembly, a screw lifting assembly or a multi-stage sleeve lifting assembly.

5. The device according to claim 1, characterized in that A detachable graphene-fluorinated resin composite baffle is provided between the reaction section and the first supporting section; a polytetrafluoroethylene plug with a hole is installed at the connecting end of the reaction section and the second supporting section.

6. The device according to claim 1, characterized in that The first bevel gear is in transmission connection with a pulley transmission mechanism, and the pulley transmission mechanism is in transmission connection with a power input device.

7. The device according to claim 1, characterized in that The multi-purpose pipe is detachable or connected to the material supply unit and the integrated absorption unit through a multi-way valve.

8. A method for wet processing phosphoric acid based on the apparatus according to any one of claims 1 to 7, characterized in that: The following steps are involved: a) Acid hydrolysis reaction: Fluorapatite ore powder with a moisture content of ≤28% and a particle size of 100 mesh is placed in a tilting reactor tube with excess concentrated sulfuric acid. The reaction is carried out at 120-160°C and 500-1000 rpm for 2-4 hours. The escaping fluorine-containing gas is recovered through an integrated absorption unit; b) Crystal reconstruction: Tilt the reactor tube to 30°-60° using the tilt adjustment mechanism, add water to adjust the liquid-to-solid ratio to 2.5-4:1, and react at 110-120°C and 100-500 rpm for 3-4 hours to convert anhydrous calcium sulfate into α-calcium sulfate hemihydrate. The escaping fluorine-containing gas is recovered via an integrated absorption unit. c) Filtration and washing: Separate the phosphoric acid filtrate and the calcium sulfate hemihydrate filter cake, and wash the filter cake in countercurrent.

9. The method according to claim 8, characterized in that The water added in step b) is a gypsum wash solution. After crystal reconstruction, the purity of α-CaSO4·0.5H2O is ≥98.5%, and the crystal size is 100-500 μm. The final phosphogypsum product has a water-soluble phosphorus content of ≤800 ppm and a water-soluble fluorine content of ≤200 ppm, and the phosphoric acid product has a water-soluble fluorine content of ≤1000 ppm.

10. The method according to claim 8, characterized in that The total fluorine emission rate in steps a) and b) is as high as 99.21%. The fluorine-containing gas is absorbed using a sodium hydroxide solution, and the concentration of the sodium fluoride solution is controlled to be 10-18 wt%.

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