CN120420934B

CN120420934B - Fluorine recovery and gypsum crystal form reconstruction integrated device and method in wet production

Info

Publication number: CN120420934B
Application number: CN202510933623.2A
Authority: CN
Inventors: 陈奕帆; 姜乐田; 李陶睿
Original assignee: Sichuan Terui Sha Chemical Technology Co ltd
Current assignee: Sichuan Zhuoyan Runze Technology Co ltd
Priority date: 2025-07-08
Filing date: 2025-07-08
Publication date: 2025-09-05
Anticipated expiration: 2045-07-08
Also published as: CN120420934A

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

Fluorine recovery and gypsum crystal form reconstruction integrated device and method in wet production

Technical Field

The invention belongs to the field of wet-process phosphoric acid preparation, relates to an integrated device and method for fluorine recovery and gypsum crystal form reconstruction in wet-process production, and particularly relates to a novel wet-process phosphoric acid processing process capable of efficiently recovering fluorine resources and realizing gypsum crystal form reconstruction.

Background

In the field of wet-process phosphoric acid production, the effective recovery of fluorine resources and the crystal form reconstruction of phosphogypsum are always important points of industry. Although the traditional wet-process phosphoric acid process realizes fluorine recovery and phosphogypsum treatment to a certain extent, a plurality of defects still exist, and improvement is needed.

In the existing wet-process phosphoric acid production process, an acidolysis reaction and a crystal form reconstruction are generally carried out by adopting a fixed reaction device respectively. The split type device design not only occupies a large area, but also can cause heat loss in the material transferring process, and reduces the energy utilization efficiency. In addition, traditional reaction unit adopts single stirring rake to mix generally, to the reaction mass of high viscosity, this kind of stirring mode often is difficult to realize intensive mixing, influences reaction efficiency and product quality.

The prior research result CN118877896A provides a new process for processing phosphoric acid by a wet method for recycling fluorine, and the high-efficiency recycling of fluorine and the quality improvement of phosphogypsum are realized for the first time through acidolysis reaction and crystal form reconstruction steps. However, as the technology is being studied deeply, the inventors found that the technology still has some limitations in practical application:

1. acidolysis reaction and crystal form reconstruction are respectively carried out in different equipment, so that the equipment utilization rate is low, and the operation is complex;

2. The risk of secondary fluorine pollution exists in the process from acidolysis reaction to crystal form reconstruction transfer, and about 2% -3% of fluorine-containing gas escapes;

3. In acidolysis and crystal form reconstruction processes, the temperature and material flow are not accurately controlled, so that the improvement of the crystal form quality and purity of phosphogypsum is limited;

4. The grain size of the crystal form reconstruction product of the constant temperature tank is still to be further improved;

5. the fineness requirement of the mineral powder is strict, more than 200 meshes are needed, and the grinding energy consumption is high.

Disclosure of Invention

Aiming at the problems, the invention provides an integrated device and method for fluorine recovery and gypsum crystal form reconstruction in wet production, which solve the problems of high energy consumption, fluorine leakage and low gypsum quality caused by equipment separation in the prior patent by means of device-process collaborative innovation, and realize the high-efficiency recovery of fluorine resources and the high-value utilization of phosphogypsum.

The integrated device and the method solve the problems of low equipment utilization rate, complex operation, insufficient material mixing, large heat loss and the like in the prior art by optimizing the structure and the process flow of the device, realize the efficient recovery of fluorine resources and the reconstruction of the high-quality crystal form of phosphogypsum, reduce the production cost and improve the production efficiency and the product quality.

The inventor through long-term exploration and try, and many times experiment and effort, innovate constantly, in order to solve above-mentioned technical problem, the technical scheme that the invention provides is, a fluorine recovery and gypsum crystal form reconfigurations integrated device in the wet process production, including integrated absorption unit, multipurpose pipe first end communicates the reaction section and communicates, the absorption bottle is connected to multipurpose pipe second end, the vacuum pump is connected to the absorption bottle, still include:

The mounting frame is provided with a mounting shaft, and a joint fork and a support bearing are mounted on the mounting shaft, wherein the joint fork comprises a first shaft sleeve and a second shaft sleeve, the shaft axes of the first shaft sleeve and the second shaft sleeve are mutually perpendicular;

The tilting reaction furnace tube sequentially comprises a first supporting section, a reaction section and a second supporting section along the axial direction, wherein a polytetrafluoroethylene coating is sprayed on the inner wall of the reaction section, and a bulge component for inhibiting tangential flow is arranged on the inner wall of the reaction section;

the rotary driving assembly is meshed with the third bevel gear through the first bevel gear and the second bevel gear and drives the tilting reaction furnace tube to rotate;

The inclination angle adjusting mechanism comprises a lifting adjusting unit and a supporting wheel set, wherein the lifting adjusting unit and the supporting wheel set are used for adjusting the inclination angle of the tilting reaction furnace tube to 30-60 degrees, and the supporting wheel set and the outer wall of the tilting reaction furnace tube form a high-amplitude mechanism.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, the acidolysis reaction and the crystal form reconstruction function are integrated in the same device, so that the seamless connection of the reaction and the crystallization process is realized. The device adopts tilting reaction furnace tube design, and is matched with an adjustable inclination mechanism, so that the inclination angle of the reaction furnace tube is flexibly adjusted in acidolysis reaction and crystal form reconstruction stages, the reaction condition is optimized, the heat loss is reduced, and the reaction efficiency and the product quality are improved.

Based on the technical scheme, the invention can also be improved as follows:

Further, the protruding members are hemispherical, prismatic or trapezoidal and uniformly distributed on the inner wall of the reaction chamber for enhancing axial flow and radial flow.

Compared with the prior art, the beneficial effects of adopting the further technical scheme are as follows:

According to the invention, the convex members are designed into hemispherical shapes, prismatic shapes or trapezoid shapes and are uniformly distributed on the inner wall of the reaction cavity, so that the fluid flow mode in the reaction cavity is further optimized, and the axial flow and the radial flow are obviously enhanced, thereby improving the mass transfer efficiency and the reaction rate, and ensuring the high efficiency of the fluorine recovery and gypsum crystal form reconstruction process.

Based on the technical scheme, the invention can also be improved as follows:

The tilting reaction furnace tube is 0 degree in acidolysis mode, the rotating speed is 500-1000 rpm, the crystal form reconstruction mode is adjusted to 35-55 degrees, and the rotating speed is 100-500 rpm.

The horizontal high-speed rotation (0 DEG/500-1000 rpm) in the acidolysis stage ensures the reaction sufficiency, the inclined low-speed rotation (35 DEG-55 DEG/100-500 rpm) in the crystal form reconstruction stage cooperatively controls the crystal growth direction and the temperature gradient, so that the purity of the alpha-hemihydrate gypsum is increased to be more than or equal to 98.5%, the crystal size is increased to be 100-500 mu m, and the filtration efficiency is higher.

Based on the technical scheme, the invention can also be improved as follows:

Further, the lifting adjusting unit of the inclination angle adjusting mechanism is a hydraulic lifting assembly, a screw lifting assembly or a multi-stage sleeve lifting assembly.

According to the invention, the hydraulic lifting assembly, the screw lifting assembly or the multi-stage sleeve type lifting assembly is adopted as the lifting adjusting unit, so that various efficient and stable realization modes are provided for angle adjustment of the tilting reaction furnace tube, the assemblies not only can accurately control the tilting angle of the furnace tube to meet different process requirements of acidolysis and crystal form reconstruction, but also can ensure the stability and reliability of device operation, prolong the service life of equipment, and improve the flexibility and automation level of operation.

Based on the technical scheme, the invention can also be improved as follows:

the reaction section and the first support section are provided with a detachable graphene-fluorinated resin composite baffle, and the connecting end of the reaction section and the second support section is provided with a polytetrafluoroethylene plug with holes.

The graphene-fluorinated resin composite baffle plate not only effectively prevents fluoride leakage and corrosion, but also is convenient for cleaning a reaction cavity and discharging slurry due to the detachable design, so that maintenance time and cost are reduced. The polytetrafluoroethylene plug with holes further enhances the tightness and corrosion resistance of the device, simultaneously allows gas to escape, ensures the pressure stability in the reaction process, and improves the safety and reliability of operation. The improvements effectively improve the stability and durability of the device in acidolysis reaction and crystal form reconstruction, prolong the service life of equipment, and improve the fluorine recovery rate and the gypsum crystal form reconstruction efficiency.

Based on the technical scheme, the invention can also be improved as follows:

further, the first bevel gear is in transmission connection with a belt wheel transmission mechanism, and the belt wheel transmission mechanism is in transmission connection with the power input equipment.

the invention realizes stable and efficient power transmission, and enables the tilting reaction furnace tube to rotate accurately and stably, thereby improving the mixing uniformity and the reaction efficiency of reaction materials, simplifying the transmission structure and facilitating maintenance and adjustment.

Based on the technical scheme, the invention can also be improved as follows:

Further, the multipurpose pipe is connected with the material supply unit and the integrated absorption unit in a detachable mode or through a multi-way valve.

The invention obviously improves the operation flexibility and convenience of the device. The connecting mode enables the material supply and gas absorption functions to be switched rapidly in different production stages, reduces the production interruption time caused by switching operation, improves the production efficiency and reduces the maintenance cost. Meanwhile, the use of the multi-way valve can also effectively prevent cross contamination among different materials, and ensures the safety of the production process and the stability of the product quality.

The invention also provides a wet-process phosphoric acid processing method based on the device, which comprises the following steps:

a) Acidolysis reaction, namely throwing fluorapatite mineral powder with the water content less than or equal to 28% and granularity of 100 meshes and excessive concentrated sulfuric acid into a tilting reaction furnace tube, reacting for 2-4 hours at 120-160 ℃ and 500-1000 r/min, and recycling the escaped fluorine-containing gas through an integrated absorption unit;

b) The crystal form reconstruction, namely tilting a reaction furnace tube to 30-60 degrees through a tilt angle adjusting mechanism, adding water to adjust the liquid-solid ratio to 2.5-4:1, reacting for 3-4 hours at 110-120 ℃ and 100-500 r/min, converting anhydrous calcium sulfate into alpha-calcium sulfate hemihydrate, and recovering the escaped fluorine-containing gas through an integrated absorption unit;

c) Filtering and washing, namely separating phosphoric acid filtrate and a calcium sulfate hemihydrate filter cake, and countercurrent washing the filter cake.

Through acidolysis-crystal form reconstruction integrated process collaborative optimization, the comprehensive improvement of fluorine recovery rate, gypsum quality and energy efficiency is realized:

The concentration of the slurry P ₂O₅ is more than or equal to 55 percent at high temperature and high rotating speed in the acidolysis stage, and the total escaping rate of fluorine reaches 99.21 percent by combining with continuous gas absorption, the residual fluorine is absorbed for the second time in the crystal form reconstruction stage, and the water-soluble fluorine of phosphoric acid is reduced to less than or equal to 101ppm;

The inclined reactor forms a temperature gradient, and the crystal breakage is restrained by cooperation with low-speed rotation, so that the purity of the obtained alpha-hemihydrate gypsum is more than or equal to 98.5 percent, the size is 100-500 mu m, and the filtering efficiency is higher;

And a slurry transferring link is omitted, the acidolysis waste heat is directly utilized to maintain the crystal form reconstruction temperature, the granularity requirement of mineral powder is relaxed to 100 meshes, and the energy consumption and the grinding cost are greatly reduced.

Based on the technical scheme, the invention can also be improved as follows:

Further, the water added in the step b) is gypsum-washing liquid, the purity of alpha-CaSO ₄·0.5H₂ O after crystal form reconstruction is more than or equal to 98.5%, the crystal size is 100-500 mu m, the water-soluble phosphorus of the final phosphogypsum product is less than or equal to 800ppm, the water-soluble fluorine of the final phosphogypsum product is less than or equal to 200ppm, and the water-soluble fluorine of the phosphoric acid product is less than or equal to 1000ppm.

According to the invention, the gypsum-washing liquid is used for hydration reaction in the crystal form reconstruction step, so that the cyclic utilization of water resources is realized, and the production cost is reduced. The improvement effectively improves the quality of phosphogypsum and phosphoric acid, widens the application range of phosphogypsum in the fields of building materials, medical materials and the like, realizes the high-efficiency recovery of fluorine resources and the high-added-value utilization of phosphogypsum, further reduces the environmental pollution risk, and enhances the economic and environmental benefits of the whole wet-process phosphoric acid process.

Based on the technical scheme, the invention can also be improved as follows:

Further, the total escape rate of fluorine in the steps a) and b) is up to 99.21%, a sodium hydroxide solution is adopted for absorbing fluorine-containing gas, and the concentration of the sodium fluoride solution is controlled to be 10-18wt%.

According to the invention, through optimizing acidolysis reaction and crystal form reconstruction steps, the total escape rate of fluorine is up to 99.21%, and the sodium hydroxide solution is adopted to absorb fluorine-containing gas, so that the concentration of the sodium fluoride solution is precisely controlled to be 10-18wt%, the recovery efficiency and purity of fluorine resources are obviously improved, the waste of fluorine resources and the risk of environmental pollution are effectively reduced, and the economic and environmental benefits of wet-process phosphoric acid production are further improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some examples of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram showing the structure of a front view of a preferred embodiment of an integrated apparatus for fluorine recovery and gypsum crystal form reconstruction in wet process production according to the present invention.

Fig. 2 is a right-side view of the structure of fig. 1.

Fig. 3 is a left-hand structural schematic diagram of fig. 1.

Fig. 4 is a schematic rear view of the structure of fig. 1.

Fig. 5 is a schematic top view of fig. 1.

Fig. 6 is a schematic perspective view of fig. 1.

FIG. 7 is a schematic perspective view showing a crystal form reconstruction state of a preferred embodiment of an integrated apparatus for fluorine recovery and gypsum crystal form reconstruction in wet process production according to the present invention.

FIG. 8 is a schematic diagram showing a cross-sectional structure of a tilting reaction furnace tube in a preferred embodiment of an integrated apparatus for fluorine recovery and gypsum crystal form reconstruction in wet process production according to the present invention.

FIG. 9 is a schematic view of a perspective view of a yoke in a preferred embodiment of an integrated apparatus for fluorine recovery and gypsum crystal form reconstruction in wet process production according to the present invention.

The marks in the figure are respectively:

100 the mounting frame,

110 Is provided with a shaft,

A 120-degree triangular support frame,

130 Support the bearing and,

140 Knots of the fork are used for connecting the fork,

141 A first sleeve of the first sleeve,

142 A second sleeve, the second sleeve,

200 A heating assembly is provided to heat the substrate,

300-Degree-of-tilt type reaction furnace tube,

A first support section 310 is provided which has a first support,

The tail end of the shaft 311 is provided with a tail end,

312 The third bevel of the pair of teeth,

A 320 reaction section, wherein in the reaction section,

A 321 reaction chamber, a reaction,

A 322-polytetrafluoroethylene plug, the material of which is,

A protruding member of 323 the convex shape,

A second support section 330 is provided which has a first support section,

331 A multi-purpose tube,

400 Of the rotary drive assembly,

The motor 410 is operated by a motor,

The first pulley is designated 421 and,

422 A drive belt, the belt is driven by a motor,

423 A second pulley is provided, which is arranged on the first pulley,

431 A first one of the teeth of the umbrella,

432 A second one of the plurality of tines 432,

500 An inclination angle adjusting mechanism,

510 A lifting and lowering adjusting unit,

520 Support the wheelset.

Detailed Description

The following description is of one embodiment with reference to the accompanying drawings.

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, based on the embodiments of the invention, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the invention. Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.

It should be noted that like reference numerals and letters refer to like items in the following figures, and thus once an item is defined in one figure, it may not be further defined and explained in subsequent figures.

Example 1

See fig. 1 to 9. The integrated device for fluorine recovery and gypsum crystal form 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 driving assembly 400 and an inclination angle adjusting mechanism 500.

The mounting frame 100 is used as a supporting foundation of the whole device, and foundation bolt holes are formed in the bottom of the mounting frame and used for being fixed on the foundation, so that running stability is ensured. The heating assembly 200 provides heat for acidolysis reaction, especially in the initial stage, and ensures stable reaction temperature. Tilting reaction furnace tube 300 is the only place for acidolysis reaction and crystal form reconstruction. The rotary drive assembly 400 provides a rotary drive force to effect material mixing and mass transfer. The inclination adjustment mechanism 500 is responsible for adjusting the inclination angle of the tilting reaction furnace tube 300.

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

The installation frame 100 is made of 2205 steel, has the dimensions of 3000mm long, 2000mm wide and 1500mm high, is in a rectangular frame structure, and is subjected to paint spraying and corrosion prevention treatment. Of course, according to practical application requirements, the length of the mounting frame 100 can be specifically selected within the range of 500-5000 mm. The bottom of the mounting frame 100 is provided with a foundation bolt hole for fixing the whole device on a foundation and ensuring the stability of the equipment during operation. The frame structure design makes it possible to disperse the weight and acting forces of the whole device homogeneously and ensure the safety and stability of the device during operation.

The mounting shaft 110 is mounted on the top of the mounting frame 100, and is made of 45 # steel, and has a shaft diameter of 120mm and a length of 2000mm. The installation shaft is fixed on the installation frame through four high-strength bolts, so that stability of the installation shaft in the process of bearing and transmitting torque is ensured. The middle part of the mounting shaft 110 is provided with a yoke 140, and the mounting shaft 110 is provided with support bearings 130 on both sides of the yoke 140.

When the bearing of the installation shaft 110 is large, the triangular support frame 120 is arranged, wherein the triangular support frame 120 is made of Q235 steel plates with the thickness of 10mm and is triangular in shape, and the triangular support frame 120 is positioned below the yoke 140. The bottom edge of the triangular support frame 120 is fixed to the bottom of the mounting frame 100 by welding, and the vertex is connected to the middle of the mounting shaft 110. The design of the tripod 120 can effectively enhance the bearing capacity and bending rigidity of the installation shaft 110, prevent vibration and deformation caused by the overlong installation shaft, and ensure the stable operation of the device.

The support bearing 130 is a self-aligning roller bearing. The support bearings 130 are mounted on both sides of the yoke 140 on the mounting shaft 110, and are used for supporting the rotary motion of the tilting reaction furnace tube 300, reducing the load between the tilting reaction furnace tube 300 and the bevel gear assembly, and simultaneously reducing the friction force between the yoke 140 and the mounting shaft 110. The selection of the self-aligning roller bearing can automatically adapt to micro-bending and installation errors of the shaft, and the reliable operation of the device is ensured.

Referring to fig. 9, the yoke 140 is composed of a first sleeve 141 and a second sleeve 142, and axes of the first sleeve 141 and the second sleeve 142 are perpendicular to each other. The first sleeve 141 is fitted over the mounting shaft 110 and is rotatable about the mounting shaft. The second sleeve 142 is used for connecting the tail shaft 311 of the tilting reaction furnace tube 300 and is rotatably matched with the tail shaft 311. Bearings are also installed between the second shaft sleeve 142 and the tail shaft 311 to ensure smooth rotation of the tilting reaction furnace tube 300. The two shaft sleeves of the yoke 140 are respectively matched with the mounting shaft and the tail shaft 311 to realize the functions of rotation and inclination adjustment of the tilting reaction furnace tube 300. The structural design of the yoke enables the reaction furnace tube to keep stable during rotation and inclination, and equipment faults caused by interference of moving parts are avoided.

In a preferred embodiment of the present invention, the heating assembly 200 may be electrically heated, or may be heated by a heat carrier. The embodiment describes an electric heating mode, and the main components and characteristics are as follows:

The heating box furnace adopts a resistance wire heating element which is arranged outside the tilting reaction furnace tube 300 and uniformly distributed in the circumferential direction, so that the heat can be ensured to be uniformly transferred to each position of the reaction furnace tube. The shell of the heating box furnace is made of stainless steel, has good heat resistance and corrosion resistance, and is filled with heat insulation materials, so that heat dissipation is reduced, and heat efficiency is improved.

The resistance wire heating element is a high-temperature alloy resistance wire, and has high resistivity, high melting point and good oxidation resistance. The resistance wire is wound into a spiral shape and is arranged in the heating box furnace, and heat is generated by the thermal effect of current. The power of the resistance wire is designed according to the size and process requirements of the reaction furnace tube, so that enough heat can be provided to maintain the temperature required by the reaction.

And the temperature sensor is arranged in the heating box furnace and is used for monitoring the temperature of the heating assembly in real time. The thermocouple is adopted as a temperature sensor, and has the characteristics of high response speed, high precision, high temperature resistance and the like. The temperature sensor is connected with the temperature control system to realize accurate control of the heating process.

The temperature control system consists of a temperature controller, a power regulator and an 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 output of the power regulator through a PID control algorithm to realize the accurate control of heating power. The electric control system is responsible for controlling the on-off of the heating element, so that the safety and stability of the heating process are ensured.

In a preferred embodiment of the present invention, the tilting reaction furnace tube 300 is a core component of an integrated fluorine recovery and gypsum crystal reconstruction device in wet production. Referring to fig. 8, the tilting reaction furnace tube 300 is formed by sequentially connecting a first support section 310, a reaction section 320 and a second support section 330 along the axial direction, and the whole is in sealed connection by adopting a flange, so that the tightness of the device in the operation process is ensured, and the gas leakage and the material loss are prevented. The reaction furnace tube is made of 2205 steel, has good strength and corrosion resistance, and can adapt to the severe chemical environment in the wet-process phosphoric acid production.

The first support section 310 includes a tail shaft 311 and a third bevel 312.

The tail shaft 311 is arranged on the same axis as the first supporting section 310 and is in rotary fit with the second sleeve 142 of the yoke 140, so that the tilting reaction furnace tube 300 can perform rotary motion under the constraint of the second sleeve 142. The tail shaft 311 is connected with the yoke 140 through a bearing, the tail shaft 311 is tightly matched with the inner ring of the bearing, the yoke 140 is tightly matched with the outer ring of the bearing, and the distance between the tilting reaction furnace tube 300 and the mounting shaft 110 is ensured to be consistent.

A third bevel gear 312 is mounted on the end of the tail shaft 311. The third bevel gear 312 is meshed with the first bevel gear 431 and the second bevel gear 432 of the rotary driving assembly 400 to form a part of a gear transmission system, so as to realize the rotary driving of the tilting reaction furnace tube 300.

A detachable graphene-fluorinated resin composite baffle is arranged between the reaction section 320 and the first support section 310, and can effectively prevent leakage of corrosive gas and materials in the reaction process, and meanwhile, the detachable graphene-fluorinated resin composite baffle is convenient to detach and clean, and reduces maintenance time and cost.

The reaction section 320 is internally provided with a reaction cavity 321, the reaction cavity 321 is a core area for acidolysis reaction and crystal form reconstruction, the inner wall of the reaction section is sprayed with a polytetrafluoroethylene coating, the thickness of the coating is uniform, and the reaction section can effectively resist the corrosion of corrosive substances such as high-concentration sulfuric acid, hydrogen fluoride, silicon tetrafluoride and the like, so that long-term stable operation of equipment is ensured. In one embodiment, the reaction chamber is 2000mm long and 600mm in inner diameter.

The polytetrafluoroethylene plug 322 is installed at the connecting end of the reaction section 320 and the second support section 330, is made of polytetrafluoroethylene, has good chemical stability and sealing performance, can prevent leakage of gas and materials in the reaction process, is convenient for disassembly and installation of the multipurpose tube 331, and is convenient for maintenance and cleaning of equipment.

The protruding members 323 are uniformly distributed on the inner wall of the reaction chamber 321. In one embodiment, the protruding members 323 are in the form of a ladder pillar having a height of 10mm and a pitch of 20mm. The convex components can effectively destroy the laminar bottom layer of the fluid and inhibit the formation of tangential flow, thereby enhancing axial flow and radial flow, optimizing the flow mode of reaction slurry, improving mass transfer and mixing efficiency, and improving reaction efficiency and fluorine escape rate.

The second support section 330 includes a multi-purpose tube 331. The multipurpose tube 331 is arranged coaxially with the tilting reaction furnace tube 300, and the inner end sequentially passes through the second supporting section 330 and the polytetrafluoroethylene plug 322 and is communicated with the reaction section 320. In the rotation process of the tilting reaction furnace tube 300, the multipurpose tube 331 can keep synchronous rotation and is externally connected with a rotary joint, and the multipurpose tube 331 can be always kept fixed by installing a sealing bearing between the polytetrafluoroethylene plug 322 and the multipurpose tube 331. The outer end of the multipurpose pipe can be detachably connected with the material supply unit and the integrated absorption unit according to production process requirements, and the material supply unit comprises a water supply unit.

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 in the drawing) in which sodium hydroxide solution is contained for absorption of escaping fluorine-containing gas. The absorption bottle is connected with a vacuum pump, and fluorine-containing gas is led into the absorption bottle through negative pressure, so that fluorine resources are effectively recovered.

In a preferred embodiment of the present invention, the rotary drive assembly 400 is responsible for driving the rotation of the tilt reaction furnace tube 300.

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

The first pulley 421 is mounted on the output shaft of the motor 410. The belt 422 adopts a V-belt, has high tensile strength and good elasticity, and can effectively transmit power and reduce the slipping phenomenon in the transmission process. The second pulley 423 is mounted on the mounting shaft 110. The first bevel gear 431 is installed at the other side of the second pulley 423 to coaxially and synchronously rotate with the second pulley 423 as a driving 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 tooth 312 is located between the first tooth 431 and the second tooth 432 and intermeshes with both.

The motor 410 smoothly transmits power to the bevel gear set through a combination of pulleys and a transmission belt. The belt transmission has the characteristics of buffering and absorbing vibration, can reduce impact load when the motor is started, and prolongs the service life of equipment.

The design of the bevel gear set can change the rotation direction by 90 degrees, and simultaneously adjust the rotation speed and the torque. The engagement of the first and second tines 431, 432 transfers torque to the third tines 312 of the first support section 310 of the tilt-type reactor tube 300, which drives the reactor tube to rotate. The high-precision machining of the bevel gear ensures the stability and accuracy of transmission.

The rotation speed and torque output of the tilting reaction furnace tube 300 can be flexibly adjusted by selecting pulleys with different diameters and bevel gears with different numbers of teeth so as to adapt to different process requirements.

All parts are made of the existing high-strength materials and subjected to precision machining and heat treatment, so that the reliability and durability of the rotary driving assembly in a severe working environment are ensured.

In a preferred embodiment, a gearbox is also mounted between the motor 410 and the first pulley 421. The speed changing box is recommended to adopt a planetary speed changing box, and the speed ratio range is preferably 0.5-2.0.

The inclination angle adjustment mechanism 500 is used for adjusting the inclination angle of the tilting reaction furnace tube 300.

In a preferred embodiment of the present invention, the elevation adjustment unit 510 employs a hydraulic elevation mechanism, which is composed of a hydraulic pump station, a hydraulic cylinder, and a control system. The hydraulic pump station provides a high-pressure oil source and drives the hydraulic cylinder to stretch out and draw back, so that the supporting wheel set 520 is driven to move up and down. The hydraulic lifting mechanism has the characteristics of strong bearing capacity, stable lifting, accurate positioning and the like, and can accurately adjust the inclination angle of the tilting reaction furnace tube 300 to 30-60 degrees according to the process requirements. The control system adopts PLC control, can realize automatic operation, improves production efficiency and security.

The supporting wheel set 520 is disposed at the top of the lifting adjusting unit 510, and is composed of two high-strength and wear-resistant supporting wheels, which are respectively located at two sides of the vertical opposite sides of the tilting reaction furnace tube 300. The supporting wheel group contacts with the outer wall of the tilting reaction furnace tube 300 and forms a high-amplitude mechanism, so that the reaction furnace tube is ensured to be stably supported in the tilting process, the furnace tube is prevented from shaking and shifting, and the safety and the stability of the production process are ensured. The design of the supporting wheel set 520 can adapt to the reaction furnace tubes with different diameters, and has good universality and adjustability.

The following is a description of a method for producing wet phosphoric acid using the integrated apparatus for fluorine recovery and gypsum crystal form reconstruction in the wet process of example 1. In the following method embodiment and comparative example, 1000kg of fluorapatite mineral powder is used as raw materials, wherein the content of P ₂O₅ is 28.78%, the content of fluorine is 2.37%, the content of amorphous SiO ₂ is 5.04%, the content of water is 26%, D ₅₀ is expanded to 100 meshes from 200 meshes in the original method, the concentration of sulfuric acid is 98%, the addition amount is 106% of the stoichiometric ration of acidolysis phosphorite, and the acidolysis reaction time is shortened to 2 hours from 6 hours. The fluorine gas evolved during acidolysis is absorbed using sodium hydroxide solution. The temperature of the absorption liquid is strictly controlled to be 50-55 ℃, and the vacuum degree of the absorption system is maintained to be about 90kPa.

The tilting reaction furnace tube 300 is kept in a horizontal state (0 DEG) in the acidolysis step, and the rotating speed is 750 rpm, so that the full mixing reaction of the fluorapatite mineral powder and the concentrated sulfuric acid is ensured, and the escape rate of fluorine is improved. In the crystal form reconstruction step, the inclination angle of the tilting reaction furnace tube 300 is adjusted to 45 degrees by the inclination angle adjusting mechanism 500, and the rotation speed is reduced to 200 revolutions per minute, so that the conversion of anhydrous calcium sulfate into alpha-calcium sulfate hemihydrate is promoted, and excessive abrasion and energy consumption are avoided.

Example 2

Acidolysis step, namely reacting for 2 hours at 140 ℃, wherein the fluorine content in the acidolysis slurry is 764ppm, and the mass fraction of P ₂O₅ is 59.03%.

And the crystal form reconstruction step is that the reaction is carried out for 4 hours at the temperature of 110 ℃, the mass ratio of the phosphorite to the water is 1:2, and the mass ratio of the phosphorite to the sulfuric acid is 1:1.25.

The absorption step is that acidolysis and crystal form reconstruction process continuously absorb, the temperature of the absorption liquid is 50 ℃ and the concentration of fluosilicic acid is 15%.

And filtering, namely washing the filter cake with water for 3 times in countercurrent.

The final effect is that the escaping rate of fluorine in the acidolysis process is 95.14%, the total escaping rate of fluorine is 97.33%, the mass fraction of P ₂O₅ in the phosphoric acid product is 42.65%, the water-soluble fluorine is 305ppm, the calcium sulfate hemihydrate content in the phosphogypsum product is 96.45%, the crystal size is 100-300 mu m, the water-soluble phosphorus content is 625ppm, and the water-soluble fluorine content is 153ppm.

Example 3

Acidolysis step, namely reacting for 2 hours at 150 ℃, wherein the fluorine content in the slurry after acidolysis is 423ppm, and the mass fraction of P ₂O₅ is 60.12%.

And the crystal form reconstruction step is that the reaction is carried out for 4 hours at the temperature of 110 ℃, the mass ratio of the phosphorite to the water is 1:2.5, and the mass ratio of the phosphorite to the sulfuric acid is 1:1.2.

The final effect is that the escaping rate of fluorine in the acidolysis process is 96.28%, the total escaping rate of fluorine is 98.69%, the mass fraction of P ₂O₅ in the phosphoric acid product is 43.89%, the water-soluble fluorine is 168ppm, the calcium sulfate hemihydrate content in the phosphogypsum product is 97.16%, the crystal size is 100-300 mu m, the water-soluble phosphorus content is 609ppm, and the water-soluble fluorine content is 121ppm.

Example 4

Acidolysis step, namely reacting for 2 hours at 160 ℃, wherein the fluorine content in the acidolysis slurry is 276ppm, and the mass fraction of P ₂O₅ is 61.23%.

And the crystal form reconstruction step is that the reaction is carried out for 4 hours at the temperature of 110 ℃, the mass ratio of the phosphorite to the water is 1:2.25, and the mass ratio of the phosphorite to the sulfuric acid is 1:1.35.

The absorption step is that acidolysis and crystal form reconstruction process continuously absorb, the temperature of the absorption liquid is 55 ℃ and the concentration of fluosilicic acid is 15%.

The final effect is that the escaping rate of fluorine in the acidolysis process is 97.34%, the total escaping rate of fluorine is 99.21%, the mass fraction of P ₂O₅ in the phosphoric acid product is 44.74%, the water-soluble fluorine is 101ppm, the calcium sulfate hemihydrate content in the phosphogypsum product is 98.88%, the crystal size is 100-300 mu m, the water-soluble phosphorus content is 667ppm, and the water-soluble fluorine content is 126ppm.

Comparative example

Acidolysis step, namely reacting for 2 hours at 150 ℃, wherein the fluorine content in the acidolysis slurry is 1.38%, and the mass fraction of P ₂O₅ is 55.65%.

The absorption step is that only acidolysis is carried out, the temperature of the absorption liquid is 50 ℃, and the concentration of fluosilicic acid is 15%.

And (3) reconstructing a crystal form of the constant temperature tank, namely reacting for 4 hours at 110 ℃, wherein the mass ratio of the phosphorite to water is 1:2.25, and the mass ratio of the phosphorite to sulfuric acid is 1:1.35.

The final effect is that the escaping rate of fluorine in acidolysis process is 68.45%, the total escaping rate of fluorine is 68.45%, the mass fraction of P ₂O₅ in phosphoric acid product is 42.57%, water-soluble fluorine is 1165ppm, calcium sulfate hemihydrate in phosphogypsum product is 95.23%, crystal size is about 50 μm, water-soluble phosphorus content is 1064ppm, and water-soluble fluorine content is 348ppm.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed, mechanically connected, electrically connected, directly connected, indirectly connected via an intervening medium, or in communication between two elements or in an interaction relationship between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that the above-mentioned preferred embodiment should not be construed as limiting the invention, and the scope of the invention should be defined by the appended claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and such modifications and adaptations are intended to be comprehended within the scope of the 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 thereto, characterized in that it also comprises:

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 is characterized in that the protruding members are hemispherical, prismatic or trapezoidal in shape and are evenly distributed on the inner wall of the reaction chamber to enhance axial flow and radial flow.

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

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

6 . The device according to claim 1 , wherein 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 it comprises the following steps:

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 fluorine-containing gas released 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 gypsum washing liquid, the purity of α- _CaSO4 · _0.5H2O after crystal reconstruction 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.

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%; sodium hydroxide solution is used to absorb the fluorine-containing gas, and the concentration of the sodium fluoride solution is controlled to be 10-18 wt%.