Preparation method and device for phosphorus pentafluoride

Abstract

Provided in the present invention are a preparation method and device for phosphorus pentafluoride. The preparation method comprises the following steps: 1) subjecting a hexafluorophosphoric acid solution to a first atomization treatment, so as to obtain atomized hexafluorophosphoric acid; and 2) subjecting a sulfuric acid solution and the atomized hexafluorophosphoric acid to a gas-liquid contact reaction at 80-140°C, so as to obtain phosphorus pentafluoride and a post-reaction solution. The preparation method for phosphorus pentafluoride provided by the present invention can prepare high-purity phosphorus pentafluoride, and has the advantages of a high reaction efficiency, a simple process, etc.

Description

A method and apparatus for preparing phosphorus pentafluoride

[0001] Priority information

[0002] This application claims priority and benefit to patent application 202410975941.0 filed with the China National Intellectual Property Administration on July 19, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a method and apparatus for preparing phosphorus pentafluoride, belonging to the field of chemical material preparation technology. Background Technology

[0004] With the rapid development of the new energy industry, especially the lithium battery market, the demand for lithium hexafluorophosphate (LiPF6), a key component of electrolyte lithium salts, is increasing. Currently, lithium hexafluorophosphate is prepared industrially using a mixed acid gasification method. This method typically involves reacting a hexafluorophosphoric acid solution with sulfuric acid to release phosphorus pentafluoride (PF5), which is then further synthesized with lithium-containing compounds such as lithium hydroxide or lithium carbonate to obtain the target product.

[0005] However, the existing mixed acid gasification method has several technical bottlenecks and operational difficulties. For example, the reaction is violent or incomplete, resulting in low product purity and yield. Heating control is difficult, which may not only disrupt the reaction equilibrium and reduce gasification efficiency, but may also lead to equipment damage and safety hazards. Intermittent production results in low production efficiency.

[0006] Therefore, optimizing reaction conditions to improve the purity of phosphorus pentafluoride, reduce the generation of byproducts, and increase production efficiency are problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0007] This invention provides a method for preparing phosphorus pentafluoride, which can produce high-purity phosphorus pentafluoride, and the preparation method is simple and has high production efficiency.

[0008] This invention provides an apparatus for preparing phosphorus pentafluoride, which provides excellent preparation conditions for the preparation of phosphorus pentafluoride and facilitates the preparation of high-purity phosphorus pentafluoride.

[0009] This invention provides a method for preparing phosphorus pentafluoride, comprising the following steps:

[0010] 1) The hexafluorophosphate solution is subjected to a first atomization treatment to obtain atomized hexafluorophosphate;

[0011] 2) The sulfuric acid solution is reacted with atomized hexafluorophosphoric acid at 80-140℃ to obtain phosphorus pentafluoride gas and the remaining reaction liquid.

[0012] In the preparation method of phosphorus pentafluoride as described above, the droplet size in the atomized hexafluorophosphoric acid is 5-200 μm.

[0013] In the preparation method of phosphorus pentafluoride as described above, the first atomization treatment is ultrasonic atomization treatment, the atomization temperature of the ultrasonic atomization treatment is 25-60℃, the atomization treatment rate is 200-1000kg / h, and the ultrasonic frequency is 1.4-1.7MHz.

[0014] In the method for preparing phosphorus pentafluoride as described above, the contact reaction is a reverse contact reaction.

[0015] In the method for preparing phosphorus pentafluoride as described above, the sulfuric acid solution participates in the contact reaction in a spray state.

[0016] In the preparation method of phosphorus pentafluoride as described above, the reaction time of the contact reaction is 0.1-3 min, and the temperature of the phosphorus pentafluoride is 100-150℃.

[0017] The method for preparing phosphorus pentafluoride as described above, wherein the hexafluorophosphoric acid solution comprises, by mass percentage, 39.5-65% hexafluorophosphoric acid, 25-55.5% hydrofluoric acid, and 5-10% water.

[0018] The sulfuric acid solution has a mass concentration of over 98%.

[0019] In the method for preparing phosphorus pentafluoride as described above, the volume flow ratio of the sulfuric acid solution to the atomized hexafluorophosphoric acid is 1:(3-1).

[0020] The method for preparing phosphorus pentafluoride as described above further includes the following steps after step 2):

[0021] At least a portion of the reaction residue is mixed with the sulfuric acid solution and circulated to participate in the contact reaction.

[0022] In the method for preparing phosphorus pentafluoride as described above, the reaction residue includes a first portion of residue and a second portion of residue, wherein...

[0023] The first portion of the remaining liquid is used to mix with the sulfuric acid solution and participate in the contact reaction in a cyclical manner;

[0024] The second portion of the remaining liquid was subjected to a second atomization treatment and a thermal decomposition treatment in sequence to obtain phosphorus pentafluoride gas;

[0025] The flow rate ratio of the first portion of residual liquid to the second portion of residual liquid is (15-30):1.

[0026] The present invention provides an apparatus for phosphorus pentafluoride, comprising a first atomizing unit and a contact unit. The first atomizing unit is used to atomize the hexafluorophosphate solution, and the contact unit is used to react sulfuric acid solution and atomized hexafluorophosphate. The atomizing outlet of the first atomizing unit is connected to the atomized liquid raw material inlet of the contact unit.

[0027] In the phosphorus pentafluoride apparatus described above, the elevation of the sulfuric acid solution inlet in the contact unit is higher than the elevation of the atomizing liquid feed inlet, and the orientation of the sulfuric acid inlet is opposite to that of the atomizing liquid feed inlet.

[0028] In the phosphorus pentafluoride apparatus described above, the contact unit is provided with N spray elements, the inlet of each spray element is connected to the sulfuric acid solution inlet, and there is a gap between the N spray elements and the inner wall of the contact unit.

[0029] In the phosphorus pentafluoride apparatus described above, the contact unit is a reaction tower, and the height-to-diameter ratio of the reaction tower is (3-10):1.

[0030] In the phosphorus pentafluoride apparatus described above, the bottom outlet of the contact unit is connected to the sulfuric acid solution inlet.

[0031] The phosphorus pentafluoride apparatus as described above further includes a second atomizing unit and a pyrolysis unit, wherein the bottom outlet of the contact unit is also connected to the inlet of the second atomizing unit, and the outlet of the second atomizing unit is connected to the inlet of the pyrolysis unit.

[0032] The method for preparing phosphorus pentafluoride provided by this invention increases the mass transfer interface area and the number of reactive centers by atomizing a hexafluorophosphate solution. This improves the reaction efficiency of the contact reaction between atomized hexafluorophosphate and sulfuric acid, and makes the reaction temperature more controllable, thus maintaining stable reaction conditions and increasing the purity of phosphorus pentafluoride. Subsequently, the atomized hexafluorophosphate is reacted with a sulfuric acid solution. The sulfuric acid solution provides a non-reactive medium and a highly efficient heat source. Hexafluorophosphate absorbs the heat from the sulfuric acid solution, overcoming intermolecular attraction and the activation energy required for its decomposition. Furthermore, atomization and the contact reaction allow for rapid separation of phosphorus pentafluoride gas from the liquid phase, facilitating gas collection and reducing the possibility of phosphorus pentafluoride recombinating into hexafluorophosphate or other byproducts in the liquid phase. This improves the purity and production efficiency of phosphorus pentafluoride.

[0033] The apparatus for preparing phosphorus pentafluoride provided by this invention is applicable to the preparation method of phosphorus pentafluoride provided by this invention. The apparatus can precisely control the atomization temperature, atomization amount and reaction temperature of the contact reaction, so that hexafluorophosphoric acid can be efficiently thermally decomposed into phosphorus pentafluoride, thereby achieving the preparation of high-purity phosphorus pentafluoride. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0035] This invention provides a method for preparing phosphorus pentafluoride, comprising the following steps:

[0036] 1) The hexafluorophosphate solution is subjected to a first atomization treatment to obtain atomized hexafluorophosphate;

[0037] 2) The sulfuric acid solution is reacted with atomized hexafluorophosphoric acid at 80-140℃ to obtain phosphorus pentafluoride gas and the remaining reaction liquid.

[0038] Specifically, in step 1), the hexafluorophosphate solution is subjected to a first atomization treatment to obtain atomized hexafluorophosphate.

[0039] The hexafluorophosphate solution of the present invention comprises hexafluorophosphate solvent and hydrofluoric acid solution. The present invention does not limit the mass concentration of the hexafluorophosphate solution and can be selected according to actual needs.

[0040] The present invention does not limit the specific parameters of the first atomization process, and can be selected according to actual needs.

[0041] Step 2): At 80-140℃, the sulfuric acid solution is brought into contact with the atomized hexafluorophosphoric acid obtained in step 1) to undergo a contact reaction, resulting in phosphorus pentafluoride gas and the remaining reaction liquid.

[0042] The present invention does not limit the mass percentage of sulfuric acid solution, and can be selected according to actual needs.

[0043] The present invention does not limit the specific parameters of the contact reaction, which can be selected according to actual needs.

[0044] The preparation method of this invention first involves atomizing a hexafluorophosphate solution, breaking it into fine droplets. Then, the atomized hexafluorophosphate is reacted with a sulfuric acid solution. On one hand, atomization significantly increases the mass transfer interface area and the number of reactive centers, which is beneficial for improving the reaction efficiency of the contact reaction between the atomized hexafluorophosphate and sulfuric acid. Furthermore, it allows for more controllable temperature control during the contact reaction, avoiding localized overheating during direct contact between the hexafluorophosphate and sulfuric acid solutions, thus helping to maintain stable reaction conditions, thereby improving the purity of phosphorus pentafluoride and reducing HF gas contamination in the gas phase. On the other hand… In this contact reaction, the sulfuric acid solution provides a non-reactive medium and a highly efficient heat source. Hexafluorophosphoric acid absorbs the heat from the sulfuric acid solution, thereby overcoming the intermolecular attraction and the activation energy required for its own decomposition, thus converting hexafluorophosphoric acid into gaseous phosphorus pentafluoride. This contact reaction enables efficient thermal decomposition of hexafluorophosphoric acid, which is beneficial to improving the production efficiency of phosphorus pentafluoride. Furthermore, this method achieves continuous operation, eliminating the need for tedious and precise manual control of the amount of sulfuric acid added. Instead, it utilizes the exothermic reaction itself to drive the decomposition of hexafluorophosphoric acid, effectively reducing energy consumption and human error, and improving production safety and stability.

[0045] Furthermore, atomization and contact reaction can rapidly separate phosphorus pentafluoride gas from the liquid phase system, which is beneficial for its collection and reduces the possibility of phosphorus pentafluoride recombinating into hexafluorophosphate or other byproducts in the liquid phase system. This helps improve the purity and production efficiency of phosphorus pentafluoride. Simultaneously, the water and hydrofluoric acid in the hexafluorophosphate solution can react with sulfur trioxide in the system to produce sulfuric acid and fluorosulfonic acid. These two reactions are accompanied by significant exothermic effects, further providing energy for the thermal decomposition of hexafluorophosphate, thereby maximizing the production efficiency of phosphorus pentafluoride.

[0046] In one specific embodiment, the droplet size in the atomized hexafluorophosphoric acid is 5-200 μm, for example, droplet sizes of 5 μm, 10 μm, 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, or 200 μm. When the droplet size in the atomized hexafluorophosphoric acid is within the above range, the heat transfer surface area and reaction contact surface area of ​​the droplets in the contact reaction can be increased to a greater extent, the endothermic mass transfer effect of the droplets in the atomized hexafluorophosphoric acid can be further enhanced, thereby increasing the thermal decomposition efficiency of hexafluorophosphoric acid to a greater extent, and allowing for greater control of the reaction temperature in the contact reaction. Simultaneously, it enables faster separation of phosphorus pentafluoride gas from the liquid phase, thereby further improving the purity of phosphorus pentafluoride.

[0047] In one specific embodiment, the first atomization treatment is ultrasonic atomization treatment. The atomization temperature of the ultrasonic atomization treatment is 25-60℃, for example, the atomization temperature is 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃ or 60℃, etc. The atomization treatment rate is 200-1000kg / h, for example, the atomization treatment rate is 200kg / h, 300kg / h, 400kg / h, 500kg / h, 600kg / h, 700kg / h, 800kg / h, 900kg / h or 1000kg / h, etc. The ultrasonic frequency is 1.4-1.7MHz, for example, the ultrasonic frequency is 1.4MHz, 1.45MHz, 1.5MHz, 1.55MHz, 1.6MHz, 1.65MHz or 1.7MHz, etc. When the parameters of the first atomization treatment are within the above range, it is beneficial to control the droplets in the atomized hexafluorophosphoric acid within the range of 5-200μm, thereby ensuring the efficient thermal decomposition of the atomized hexafluorophosphoric acid, and enabling greater control over the reaction temperature of the contact reaction, as well as faster separation of phosphorus pentafluoride gas from the liquid phase, resulting in higher purity of phosphorus pentafluoride. Furthermore, this atomization treatment volume can further accelerate the production speed of phosphorus pentafluoride, avoiding the waste of energy and time caused by low atomization treatment volume.

[0048] In one specific embodiment, the contact reaction is a reverse contact reaction. Specifically, the contact reaction between atomized hexafluorophosphoric acid and sulfuric acid solution is a reverse contact reaction, meaning that the flow directions of the atomized hexafluorophosphoric acid and sulfuric acid solution are opposite. When the contact reaction is a reverse contact reaction, the atomized hexafluorophosphoric acid and sulfuric acid solution form a good countercurrent collision contact, allowing the temperature of hexafluorophosphoric acid to rapidly reach its decomposition temperature. This dynamic and highly refined contact mode is more conducive to the rapid generation of phosphorus pentafluoride gas and reduces mass transfer resistance, further enhancing mass transfer efficiency, thereby increasing the reaction rate of the contact reaction to a greater extent and resulting in higher production efficiency of phosphorus pentafluoride.

[0049] In one specific embodiment, the sulfuric acid solution participates in the contact reaction in a spray state. Specifically, the sulfuric acid solution is presented as a sulfuric acid spray liquid, which reacts with atomized hexafluorophosphoric acid. When the sulfuric acid solution is in a spray state, the contact area between the sulfuric acid solution and the atomized hexafluorophosphoric acid can be further increased, resulting in higher heat transfer efficiency of the sulfuric acid solution. This allows the atomized hexafluorophosphoric acid to reach its decomposition temperature more quickly, thereby further improving production efficiency. Furthermore, it can reduce the contact time between the atomized hexafluorophosphoric acid and the sulfuric acid solution, inhibiting the formation of fluorosulfonic acid and thus resulting in higher purity of phosphorus pentafluoride.

[0050] In one specific embodiment, the reaction time of the contact reaction is 0.1-3 min, for example, 0.1 min, 0.5 min, 1 min, 1.5 min, 2 min, 2.5 min, or 3 min, etc., and the temperature of phosphorus pentafluoride is 100-150℃, for example, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, or 150℃, etc. When the reaction time and temperature of phosphorus pentafluoride are within the above ranges, the atomized hexafluorophosphoric acid and the sulfuric acid solution can come into sufficient contact, allowing more heat from the sulfuric acid solution to be transferred to the atomized hexafluorophosphoric acid. This provides more heat energy for the thermal decomposition of hexafluorophosphoric acid, enabling it to reach its decomposition temperature more quickly. This ensures the high-purity preparation of phosphorus pentafluoride and improves its production efficiency.

[0051] In one specific embodiment, the hexafluorophosphate solution comprises, by mass percentage, 39.5-65% hexafluorophosphate, 25-55.5% hydrofluoric acid, and 5-10% water; the sulfuric acid solution has a mass concentration higher than 98%. When the mass percentages of the hexafluorophosphate and sulfuric acid solutions are within the above ranges, the atomized hexafluorophosphate and sulfuric acid solutions can undergo better contact reaction, and the formation of byproducts in the contact reaction can be reduced, thereby resulting in higher purity and production efficiency of phosphorus pentafluoride.

[0052] In one specific embodiment, the volumetric flow rate ratio of sulfuric acid solution to atomized hexafluorophosphoric acid is 1:(3-1), for example, a volumetric flow rate ratio of 1:1, 1, 1:1.5, 1:2, 1:2.5, or 1:3. When the volumetric flow rate ratio of sulfuric acid solution to atomized hexafluorophosphoric acid is within the above range, the sulfuric acid solution can provide sufficient heat for atomized hexafluorophosphoric acid, allowing for sufficient thermal decomposition of hexafluorophosphoric acid. This further suppresses the formation of byproducts in the contact reaction, thereby further improving the purity and production efficiency of phosphorus pentafluoride, while avoiding waste of hexafluorophosphoric acid or sulfuric acid solution and reducing production costs.

[0053] In one specific embodiment, after step 2), the method further includes the following step: mixing at least a portion of the reaction residue with a sulfuric acid solution and cyclically participating in the contact reaction. Specifically, after step 2), a portion of the reaction residue is mixed with a sulfuric acid solution and returned to the contact reaction, allowing the reaction residue to react with atomized hexafluorophosphoric acid. The reaction residue of this invention includes unreacted hexafluorophosphoric acid and unreacted sulfuric acid solution. Cycling a portion of the reaction residue with the sulfuric acid solution allows for the use of unreacted sulfuric acid solution in the contact reaction with hexafluorophosphoric acid, thereby ensuring complete utilization of the sulfuric acid solution, reducing the amount of sulfuric acid solution used, and saving production costs.

[0054] In one specific embodiment, the reaction residue includes a first portion of residue and a second portion of residue. The first portion of residue is used to mix with sulfuric acid solution and participate in the contact reaction in a cyclic manner. The second portion of residue is subjected to a second atomization treatment and a thermal decomposition treatment in sequence to obtain phosphorus pentafluoride gas. The flow ratio of the first portion of residue and the second portion of residue is (15-30):1, for example, a flow ratio of 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, or 30:1, etc.

[0055] Specifically, the reaction residue is divided into a first part and a second part, and the flow ratio of the first part and the second part is controlled at (15-30):1. The first part is mixed with sulfuric acid solution and returned to the contact reaction, so that the unreacted sulfuric acid solution in the reaction residue can react with hexafluorophosphoric acid, thereby ensuring the complete utilization of sulfuric acid solution and reducing the amount of raw materials input. At the same time, the second part is subjected to a second atomization treatment to obtain atomized reaction residue. Then, the atomized reaction residue is subjected to thermal decomposition treatment to obtain phosphorus pentafluoride gas.

[0056] The present invention does not limit the specific parameters of the second atomization treatment, which can be selected according to actual needs. As long as the second part of the residual liquid is atomized into droplets with a particle size of 5-200μm, for example, the atomization temperature is 30-150℃ and the atomization treatment rate is 2-100kg / h.

[0057] The present invention does not limit the specific parameters of the pyrolysis treatment, which can be selected according to actual needs. For example, the reaction temperature of the pyrolysis treatment is 100-150℃ and the reaction time is 3-10min.

[0058] This invention involves atomizing and thermally decomposing the second portion of the residual liquid to convert unreacted hexafluorophosphoric acid into phosphorus pentafluoride, achieving continuous thermal decomposition of hexafluorophosphoric acid. This allows for uninterrupted utilization of all input hexafluorophosphoric acid, significantly improving overall production efficiency and resource utilization. Furthermore, by extracting the second portion of the residual liquid from the contact reaction system, the low-concentration solution generated from the reaction of sulfur trioxide with water and hydrofluoric acid can be removed. Fresh sulfuric acid solution is continuously added to the contact reaction to ensure sufficient sulfur trioxide participation, thus enabling the continuous and efficient preparation of high-purity phosphorus pentafluoride.

[0059] In one specific embodiment, the present invention combines phosphorus pentafluoride gas obtained from a contact reaction with phosphorus pentafluoride gas obtained from thermal decomposition, and then performs high-pressure low-temperature treatment and distillation to obtain high-purity phosphorus pentafluoride. The pressure of the high-pressure low-temperature treatment is 1-3 MPa, for example, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, or 3 MPa, and the temperature is -30-20℃, for example, -30℃, -25℃, -20℃, -15℃, -10℃, or -5℃. The distillation temperature is -10 to 20°C, for example, -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, or 20°C. The distillation pressure is 0.7-2.7 MPa, such as 0.7 MPa, 0.9 MPa, 1.1 MPa, 1.3 MPa, 1.5 MPa, 1.7 MPa, 1.9 MPa, 2.1 MPa, 2.3 MPa, 2.5 MPa, or 2.7 MPa. The distillation temperature is -10 to 20°C, such as -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, or 20°C. Using the method of this invention, high-purity phosphorus pentafluoride can be efficiently prepared. The purity of this high-purity phosphorus pentafluoride can reach up to 99.99%, with HF ≤ 25 ppm and moisture ≤ 15 ppm.

[0060] The present invention provides an apparatus for phosphorus pentafluoride, the apparatus comprising a first atomizing unit and a contact unit, the first atomizing unit being used to atomize a hexafluorophosphoric acid solution, and the contact unit being used to react sulfuric acid solution and atomized hexafluorophosphoric acid in a contact reaction, the atomizing outlet of the first atomizing unit being connected to the atomized liquid raw material inlet of the contact unit.

[0061] Specifically, the phosphorus pentafluoride apparatus provided by this invention is applicable to the phosphorus pentafluoride preparation method provided by this invention. The apparatus includes a first atomizing unit and a contact unit, with the atomizing outlet of the first atomizing unit connected to the atomizing liquid raw material inlet of the contact unit. It is understood that the first atomizing unit is used to atomize a hexafluorophosphoric acid solution to obtain atomized hexafluorophosphoric acid; the contact unit is used to react sulfuric acid solution and atomized hexafluorophosphoric acid to form phosphorus pentafluoride and a reaction residue.

[0062] In one specific embodiment, the elevation of the sulfuric acid solution inlet in the contact unit is higher than the elevation of the atomizing liquid raw material inlet, and the orientation of the sulfuric acid inlet is opposite to that of the atomizing liquid raw material inlet. Specifically, the elevation in this invention refers to the distance from the inlet along the vertical direction to the absolute datum. The fact that the elevation of the sulfuric acid solution inlet in the contact unit of this invention is higher than the elevation of the atomizing liquid raw material inlet, and that the orientation of the sulfuric acid inlet is opposite to that of the atomizing liquid raw material inlet, facilitates a reverse contact reaction between the sulfuric acid solution in a spray state and the atomized hexafluorophosphoric acid. This allows the hexafluorophosphoric acid to fully receive heat transfer from the sulfuric acid solution, resulting in efficient thermal decomposition of hexafluorophosphoric acid and ultimately achieving efficient production of high-purity phosphorus pentafluoride.

[0063] In one specific embodiment, the contact unit is provided with N spray elements, each spray element's inlet being connected to the sulfuric acid solution inlet, and the N spray elements are spaced apart from the inner wall of the contact unit. The present invention does not limit the number of spray elements and can select them according to actual needs. When spray elements are provided in the contact unit and the spray element placement area is controlled, the sulfuric acid solution can more uniformly contact the atomized hexafluorophosphoric acid in a sprayed state, and the sulfuric acid solution can be prevented from flowing down the inner wall, further expanding the contact area, thereby greatly improving the reaction rate and efficiency of the contact reaction.

[0064] In one specific embodiment, the contact unit is a reaction tower with a height-to-diameter ratio of (3-10):1, such as 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1. When the contact unit is a reaction tower and the height-to-diameter ratio is within the above range, the atomized hexafluorophosphoric acid can achieve sufficient gas-liquid contact with the sulfuric acid solution, providing sufficient time for the contact reaction, avoiding waste of raw materials, and reducing production costs.

[0065] In one specific embodiment, the bottom outlet of the contact unit is connected to the sulfuric acid solution inlet. This connection between the bottom outlet of the contact unit and the sulfuric acid solution inlet allows the residual reaction liquid from the contact reaction to be recycled back into the contact unit, thereby maximizing the utilization of the sulfuric acid solution, improving raw material utilization, and reducing production costs.

[0066] In one specific embodiment, the device further includes a second atomizing unit and a pyrolysis unit. The bottom outlet of the contact unit is also connected to the inlet of the second atomizing unit, and the outlet of the second atomizing unit is connected to the inlet of the pyrolysis unit. Specifically, the device of the present invention further includes a second atomizing unit and a pyrolysis unit. The second atomizing unit is used to atomize the second portion of the residual liquid, and the pyrolysis unit is used to perform a thermal pyrolysis reaction on the atomized reaction residual liquid. The bottom outlet of the contact unit is also connected to the inlet of the second atomizing unit, and the outlet of the second atomizing unit is connected to the inlet of the pyrolysis unit. The present invention can extract a portion of the reaction residual liquid obtained from the contact reaction through this device, and perform a second atomization treatment and thermal pyrolysis treatment, thereby further thermally decomposing the unreacted hexafluorophosphoric acid, achieving complete utilization of hexafluorophosphoric acid, and thus improving the raw material utilization rate.

[0067] The present invention will be further described in detail below through specific embodiments.

[0068] Example 1

[0069] The preparation process of phosphorus pentafluoride provided in this embodiment includes the following steps:

[0070] 1) Add hexafluorophosphate solution into the first atomization unit for the first atomization treatment to obtain atomized hexafluorophosphate;

[0071] The hexafluorophosphate solution comprises 60% hexafluorophosphate, 32% hydrofluoric acid, and 8% water by mass percentage; the atomization temperature of the first atomization treatment is 25℃, the atomization rate is 400kg / h, and the ultrasonic frequency is 1.5MHz; according to the aerosol particle size analyzer, the droplet size in the atomized hexafluorophosphate is 100μm.

[0072] 2) Atomized hexafluorophosphoric acid is introduced through the atomized liquid raw material inlet of the reaction tower, and sulfuric acid solution is added through the No. 1 spray element in the reaction tower, so that the atomized hexafluorophosphoric acid and sulfuric acid solution undergo gas-liquid contact reaction at 100°C to obtain phosphorus pentafluoride gas and reaction residue.

[0073] The elevation of the spray element is higher than that of the atomized liquid raw material inlet, and the orientation of the spray element is opposite to that of the atomized liquid raw material inlet. The distance between the spray element and the inner wall of the reaction tower is 300mm. The height-to-diameter ratio of the reaction tower is 8:1.

[0074] The sulfuric acid solution has a mass percentage of 98%, the reaction time of the contact reaction is 2.5 min, the temperature of phosphorus pentafluoride at the top of the reaction tower is 100℃, and the volume flow ratio of sulfuric acid solution to atomized hexafluorophosphoric acid is 1:2.

[0075] 3) The reaction residue is divided into a first part and a second part. The first part is returned to the spray nozzle of the reaction tower and sprayed into the reaction tower. The second part enters the second atomization unit for second atomization treatment to obtain atomized reaction residue. Then, the atomized reaction residue is introduced into the cracking unit for thermal cracking treatment to obtain phosphorus pentafluoride gas.

[0076] The flow rate ratio of the first part of the residual liquid to the second part of the residual liquid is 25:1; the atomization temperature of the second atomization treatment is 150℃ and the atomization treatment rate is 4kg / h; the thermal pyrolysis treatment has a thermal pyrolysis temperature of 140℃ and a thermal pyrolysis time of 8min.

[0077] 4) Combine the phosphorus pentafluoride gas obtained from the contact reaction with the phosphorus pentafluoride gas obtained from the thermal decomposition treatment.

[0078] 5) The combined phosphorus pentafluoride gas is subjected to high-pressure and low-temperature treatment, followed by distillation to obtain high-purity phosphorus pentafluoride;

[0079] The high-pressure low-temperature treatment has a pressure of 2 MPa and a temperature of 10℃, while the distillation treatment has a distillation pressure of 1.8 MPa and a distillation temperature of 20℃.

[0080] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 20 ppm, and the water content was 15 ppm by mass.

[0081] Example 2

[0082] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the hexafluorophosphate solution includes 65% hexafluorophosphate, 27% hydrofluoric acid, and 8% water by mass percentage.

[0083] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 18 ppm, and the water content was 13 ppm by mass.

[0084] Example 3

[0085] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the hexafluorophosphate solution includes 70% hexafluorophosphate, 22% hydrofluoric acid, and 8% water by mass percentage.

[0086] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.97%, the HF content was 40 ppm, and the water content was 20 ppm by mass.

[0087] Example 4

[0088] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the mass percentage of sulfuric acid solution is 100%.

[0089] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 18 ppm, and the water content was 12 ppm by mass.

[0090] Example 5

[0091] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the mass percentage of sulfuric acid solution is 90%.

[0092] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.92%, the HF content was 21 ppm, and the water content was 54 ppm by mass.

[0093] Example 6

[0094] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomization temperature of the first atomization treatment is 25°C, the atomization rate is 400 kg / h, and the ultrasonic frequency is 1.7 MHz. According to the aerosol particle size analyzer, the droplet size in the atomized hexafluorophosphoric acid is 50 μm.

[0095] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 21 ppm, and the water content was 15 ppm by mass.

[0096] Example 7

[0097] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomization temperature of the first atomization treatment is 25°C, the atomization rate is 400 kg / h, and the ultrasonic frequency is 1.55 MHz. According to the aerosol particle size analyzer, the droplet size in the atomized hexafluorophosphoric acid is 80 μm.

[0098] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 20 ppm, and the water content was 15 ppm by mass.

[0099] Example 8

[0100] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomization temperature of the first atomization treatment is 25°C, the atomization rate is 400 kg / h, and the ultrasonic frequency is 1.45 MHz. According to the aerosol particle size analyzer, the droplet size in the atomized hexafluorophosphoric acid is 150 μm.

[0101] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 21 ppm, and the water content was 15 ppm by mass.

[0102] Example 9

[0103] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomization temperature of the first atomization treatment is 25°C, the atomization rate is 400 kg / h, and the ultrasonic frequency is 1.4 MHz. According to the aerosol particle size analyzer, the droplet size in the atomized hexafluorophosphoric acid is 200 μm.

[0104] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 23 ppm, and the water content was 15 ppm by mass.

[0105] Example 10

[0106] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomization temperature of the first atomization treatment is 25°C, the atomization rate is 400 kg / h, and the ultrasonic frequency is 1.2 MHz. According to the aerosol particle size analyzer, the droplet size in the atomized hexafluorophosphoric acid is 220 μm.

[0107] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 31 ppm, and the water content was 15 ppm by mass.

[0108] Example 11

[0109] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomization temperature of the first atomization treatment is 40°C, the atomization rate is 200 kg / h, and the ultrasonic frequency is 1.4 MHz.

[0110] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 17 ppm, and the water content was 15 ppm by mass.

[0111] Example 12

[0112] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomization temperature of the first atomization treatment is 60°C, the atomization rate is 700 kg / h, and the ultrasonic frequency is 1.4 MHz.

[0113] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 18 ppm, and the water content was 15 ppm by mass.

[0114] Example 13

[0115] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomization temperature of the first atomization treatment is 60°C, the atomization treatment amount is 1000 kg / h, and the ultrasonic frequency is 2 MHz.

[0116] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 20 ppm, and the water content was 15 ppm by mass.

[0117] Example 14

[0118] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomized hexafluorophosphoric acid and sulfuric acid solution undergo a gas-liquid contact reaction at 80°C.

[0119] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 24 ppm, and the water content was 14 ppm by mass.

[0120] Example 15

[0121] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the atomized hexafluorophosphoric acid and sulfuric acid solution undergo a gas-liquid contact reaction at 140°C.

[0122] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 25 ppm, and the water content was 14 ppm by mass.

[0123] Example 16

[0124] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the elevation of the spray element is the same as the elevation of the atomizing liquid raw material inlet, and the orientation of the spray element is the same as the orientation of the atomizing liquid raw material inlet.

[0125] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 26 ppm, and the water content was 16 ppm by mass.

[0126] Example 17

[0127] The preparation process of phosphorus pentafluoride provided in this embodiment includes the following steps:

[0128] 1) Add hexafluorophosphate solution into the first atomization unit for the first atomization treatment to obtain atomized hexafluorophosphate;

[0129] The hexafluorophosphate solution comprises 60% hexafluorophosphate, 32% hydrofluoric acid, and 8% water by mass percentage; the atomization temperature of the first atomization treatment is 25℃, the atomization rate is 400kg / h, and the ultrasonic frequency is 1.5MHz; according to the aerosol particle size analyzer, the droplet size in the atomized hexafluorophosphate is 100μm.

[0130] 2) Atomized hexafluorophosphoric acid is introduced through the atomized liquid feed inlet of the reaction tower, and sulfuric acid solution is introduced into the bottom of the reaction tower, so that the atomized hexafluorophosphoric acid and sulfuric acid solution react at 100°C to obtain phosphorus pentafluoride gas and reaction residue.

[0131] The sulfuric acid solution has a mass percentage of 98%, the reaction time for the decomposition reaction is 2.5 min, and the temperature of phosphorus pentafluoride at the top of the reaction tower is 100℃.

[0132] 3) The reaction residue is divided into a first part of residue and a second part of residue. The first part of residue is returned to the bottom of the reaction tower, and the second part of residue enters the second atomization unit for second atomization treatment to obtain atomized reaction residue. Then, the atomized reaction residue is introduced into the cracking unit for thermal cracking treatment to obtain phosphorus pentafluoride gas.

[0133] The flow rate ratio of the first part of the residual liquid to the second part of the residual liquid is 25:1; the atomization temperature of the second atomization treatment is 150℃ and the atomization treatment rate is 4kg / h; the thermal pyrolysis treatment has a thermal pyrolysis temperature of 140℃ and a thermal pyrolysis time of 8min.

[0134] 4) Combine the phosphorus pentafluoride gas obtained from the contact reaction with the phosphorus pentafluoride gas obtained from the thermal decomposition treatment.

[0135] 5) The combined phosphorus pentafluoride gas is subjected to high-pressure and low-temperature treatment, followed by distillation to obtain high-purity phosphorus pentafluoride;

[0136] The high-pressure low-temperature treatment has a pressure of 2 MPa and a temperature of 10℃, while the distillation treatment has a distillation pressure of 1.8 MPa and a distillation temperature of 20℃.

[0137] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 28 ppm, and the water content was 17 ppm by mass.

[0138] Example 18

[0139] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the reaction time of the contact reaction is 0.1 min and the temperature of phosphorus pentafluoride at the top of the reaction tower is 150°C.

[0140] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 35 ppm, and the water content was 18 ppm by mass.

[0141] Example 19

[0142] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the reaction time of the contact reaction is 0.1 min and the temperature of phosphorus pentafluoride at the top of the reaction tower is 120°C.

[0143] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 28 ppm, and the water content was 17 ppm by mass.

[0144] Example 20

[0145] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the reaction time of the contact reaction is 1 minute and the temperature of phosphorus pentafluoride at the top of the reaction tower is 110°C.

[0146] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 24 ppm, and the water content was 15 ppm by mass.

[0147] Example 21

[0148] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the reaction time of the contact reaction is 2 minutes and the temperature of phosphorus pentafluoride at the top of the reaction tower is 100°C.

[0149] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 24 ppm, and the water content was 15 ppm by mass.

[0150] Example 22

[0151] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the reaction time of the contact reaction is 3 minutes and the temperature of phosphorus pentafluoride at the top of the reaction tower is 90°C.

[0152] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 23 ppm, and the water content was 15 ppm by mass.

[0153] Example 23

[0154] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the reaction time of the contact reaction is 3.5 min and the temperature of phosphorus pentafluoride at the top of the reaction tower is 80°C.

[0155] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 30 ppm, and the water content was 20 ppm by mass.

[0156] Example 24

[0157] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the volume flow ratio of sulfuric acid solution to atomized hexafluorophosphoric acid is 1:1.

[0158] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 22 ppm, and the water content was 15 ppm by mass.

[0159] Example 25

[0160] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the volume flow ratio of sulfuric acid solution to atomized hexafluorophosphoric acid is 1:3.

[0161] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 25 ppm, and the water content was 15 ppm by mass.

[0162] Example 26

[0163] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the volume flow ratio of sulfuric acid solution to atomized hexafluorophosphoric acid is 1:4.

[0164] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 31 ppm, and the water content was 25 ppm by mass.

[0165] Example 27

[0166] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the height-to-diameter ratio of the reaction tower is 10:1.

[0167] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 27 ppm, and the water content was 15 ppm by mass.

[0168] Example 28

[0169] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the height-to-diameter ratio of the reaction tower is 5:1.

[0170] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 28 ppm, and the water content was 15 ppm by mass.

[0171] Example 29

[0172] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the height-to-diameter ratio of the reaction tower is 3:1.

[0173] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 29 ppm, and the water content was 17 ppm by mass.

[0174] Example 30

[0175] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the height-to-diameter ratio of the reaction tower is 1:1.

[0176] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content in high-purity phosphorus pentafluoride was 41 ppm, and the water content was 25 ppm by mass.

[0177] Example 31

[0178] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the flow ratio of the first part of the residual liquid to the second part of the residual liquid is 30:1.

[0179] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 20 ppm, and the water content was 15 ppm by mass.

[0180] Example 32

[0181] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the flow ratio of the first part of the residual liquid to the second part of the residual liquid is 20:1.

[0182] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 24 ppm, and the water content was 15 ppm by mass.

[0183] Example 33

[0184] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the flow ratio of the first part of the residual liquid to the second part of the residual liquid is 15:1.

[0185] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 25 ppm, and the water content was 16 ppm by mass.

[0186] Example 34

[0187] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that the flow ratio of the first part of the residual liquid to the second part of the residual liquid is 10:1.

[0188] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 38 ppm, and the water content was 16 ppm by mass.

[0189] Example 35

[0190] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1, except that it does not include the high-pressure low-temperature treatment and distillation treatment in step 5).

[0191] GC-MS and online infrared spectroscopy tests showed that the purity of phosphorus pentafluoride was 95.7%, the HF content was 4270 ppm, and the moisture content was 30 ppm.

[0192] Example 36

[0193] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the pressure of the high-pressure low-temperature treatment is 1 MPa and the temperature is 20°C, and the distillation pressure of the distillation treatment is 2.7 MPa and the distillation temperature is -10°C.

[0194] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 24 ppm, and the water content was 15 ppm by mass.

[0195] Example 37

[0196] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the pressure of the high-pressure low-temperature treatment is 3 MPa and the temperature is -30°C, and the distillation pressure of the distillation treatment is 0.7 MPa and the distillation temperature is 20°C.

[0197] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 21 ppm, and the water content was 17 ppm by mass.

[0198] Example 38

[0199] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the pressure of the high-pressure low-temperature treatment is 2.5 MPa and the temperature is 5°C, and the distillation pressure of the distillation treatment is 1.5 MPa and the distillation temperature is 5°C.

[0200] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.99%, the HF content was 23 ppm, and the water content was 16 ppm by mass.

[0201] Example 39

[0202] The preparation process of phosphorus pentafluoride provided in this embodiment is roughly the same as that in Example 1. The difference is that the pressure of the high-pressure low-temperature treatment is 0.5 MPa and the temperature is 25°C, and the distillation pressure of the distillation treatment is 0.5 MPa and the distillation temperature is 25°C.

[0203] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.97%, the HF content was 47 ppm, and the water content was 18 ppm by mass.

[0204] Comparative Example 1

[0205] The preparation process of phosphorus pentafluoride provided in this comparative example includes the following steps:

[0206] 1) Hexafluorophosphoric acid and sulfuric acid are introduced into the raw material inlet of the reaction tower respectively, so that hexafluorophosphoric acid and sulfuric acid solution react at 100°C to obtain phosphorus pentafluoride gas and reaction residue.

[0207] The sulfuric acid solution has a mass percentage of 98%, the reaction time of the contact reaction is 2.5 min, the temperature of phosphorus pentafluoride at the top of the reaction tower is 100℃, and the volume flow ratio of sulfuric acid solution to hexafluorophosphoric acid is 1:2.

[0208] 3) The reaction residue is divided into a first part of residue and a second part of residue. The first part of residue is returned to the reaction tower, and the second part of residue enters the second atomization unit for the second atomization treatment to obtain atomized reaction residue. Then, the atomized reaction residue is introduced into the cracking unit for thermal cracking treatment to obtain phosphorus pentafluoride gas.

[0209] The flow rate ratio of the first part of the residual liquid to the second part of the residual liquid is 25:1; the atomization temperature of the second atomization treatment is 150℃ and the atomization treatment rate is 4kg / h; the thermal pyrolysis treatment has a thermal pyrolysis temperature of 140℃ and a thermal pyrolysis time of 8min.

[0210] 4) Combine the phosphorus pentafluoride gas obtained from the contact reaction with the phosphorus pentafluoride gas obtained from the thermal decomposition treatment.

[0211] 5) The combined phosphorus pentafluoride gas is subjected to high-pressure and low-temperature treatment, followed by distillation to obtain high-purity phosphorus pentafluoride;

[0212] The high-pressure low-temperature treatment has a pressure of 2 MPa and a temperature of 10℃, while the distillation treatment has a distillation pressure of 1.8 MPa and a distillation temperature of 20℃.

[0213] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.8%, the HF content was 500 ppm, and the water content was 50 ppm by mass.

[0214] Comparative Example 2

[0215] The preparation process of phosphorus pentafluoride provided in this comparative example is roughly the same as that in Example 1, except that the atomized hexafluorophosphoric acid and sulfuric acid solution are subjected to a gas-liquid contact reaction at 150°C.

[0216] GC-MS and online infrared spectroscopy tests on high-purity phosphorus pentafluoride showed that the purity of high-purity phosphorus pentafluoride was 99.87%, the HF content was 45 ppm, and the water content was 15 ppm by mass.

[0217] In summary, the method for preparing phosphorus pentafluoride provided by this invention can produce high-purity phosphorus pentafluoride, and can shorten the contact reaction time to within 10 minutes and reduce the contact reaction temperature to 80°C. Experimental results show that under the above-mentioned apparatus and method conditions, the purity of the obtained phosphorus pentafluoride can reach up to 99.99%, and the HF and moisture content in the phosphorus pentafluoride is low.

[0218] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for the preparation of phosphorus pentafluoride, wherein, The method comprises the following steps: 1) performing a first atomization treatment on a hexafluorophosphoric acid solution to obtain atomized hexafluorophosphoric acid; 2) performing a contact reaction between a sulfuric acid solution and the atomized hexafluorophosphoric acid at 80-140 ℃ to obtain phosphorus pentafluoride gas and a reaction residue.

2. The process for the preparation of phosphorus pentafluoride according to claim 1, wherein, The particle size of the droplets in the atomized hexafluorophosphoric acid is 5-200 μm.

3. The process for the preparation of phosphorus pentafluoride according to claim 1 or 2, wherein, The first atomization treatment is ultrasonic atomization treatment, the atomization temperature of the ultrasonic atomization treatment is 25-60 ℃, the atomization treatment capacity is 200-1000 kg / h, and the ultrasonic frequency is 1.4-1.7 MHz.

4. The process for the preparation of phosphorus pentafluoride according to claim 3, wherein, The contact reaction is a reverse contact reaction.

5. The process for the preparation of phosphorus pentafluoride according to claim 4, wherein, The sulfuric acid solution participates in the contact reaction in a spraying state; and / or, the reaction time of the contact reaction is 0.1-3 min, and the temperature of the phosphorus pentafluoride is 60-120 ℃.

6. The process for the preparation of phosphorus pentafluoride according to claim 5, wherein, The hexafluorophosphoric acid solution comprises, in terms of mass percentage, 39.5-65% of hexafluorophosphoric acid, 25-55.5% of hydrofluoric acid, and 5-10% of water; the mass concentration of the sulfuric acid solution is higher than 98%; and / or, The volume flow rate ratio of the sulfuric acid solution to the atomized hexafluorophosphoric acid is 1:(3-1).

7. The process for the preparation of phosphorus pentafluoride according to claim 6, wherein, After step 2), the following steps are further included: Mixing at least part of the reaction residue with the sulfuric acid solution to participate in the contact reaction.

8. The process for the preparation of phosphorus pentafluoride according to claim 7, wherein, The reaction residue comprises a first part of the residue and a second part of the residue, wherein, The first part of the residue is used to mix with the sulfuric acid solution to participate in the contact reaction; The second part of the residue is sequentially subjected to a second atomization treatment and a thermal cracking treatment to obtain phosphorus pentafluoride gas; The flow rate ratio of the first part of the residue to the second part of the residue is (15-30):

1.

9. The process for the preparation of phosphorus pentafluoride according to claim 8, wherein, After the thermal cracking treatment, the following steps are further included: Combining the phosphorus pentafluoride gas obtained by the contact reaction with the phosphorus pentafluoride gas obtained by the thermal cracking treatment, and then performing high-pressure low-temperature treatment and rectification treatment to obtain high-purity phosphorus pentafluoride; The pressure of the high-pressure low-temperature treatment is 1-3 MPa, and the temperature is -30-20 ℃; the rectification pressure of the rectification treatment is 0.7-2.7 MPa, and the rectification temperature is -10-20 ℃.

10. An apparatus for phosphorus pentafluoride, wherein, The device comprises a first atomization unit and a contact unit, the first atomization unit is used to perform atomization treatment on the hexafluorophosphoric acid solution, and the contact unit is used to perform a contact reaction between a sulfuric acid solution and atomized hexafluorophosphoric acid; the atomization outlet of the first atomization unit is in communication with the atomized liquid raw material inlet of the contact unit.

11. The apparatus of claim 10, wherein, The elevation of the sulfuric acid solution inlet in the contact unit is higher than the elevation of the atomized liquid raw material inlet, and the direction of the sulfuric acid inlet is opposite to the direction of the atomized liquid raw material inlet.

12. The apparatus of claim 11, wherein, The contact unit is provided with N spraying members, the inlet of each spraying member is in communication with the sulfuric acid solution inlet, and the N spraying members have a spacing from the inner wall of the contact unit.

13. The apparatus of claim 12, wherein the phosphorus pentafluoride is generated by the reaction of phosphorus trichloride and hydrogen fluoride. The contact unit is a reaction tower, and the height-diameter ratio of the reaction tower is (3-10):

1.

14. The apparatus of claim 13, wherein the phosphorus pentafluoride is generated by the reaction of phosphorus trichloride and hydrogen fluoride. The bottom outlet of the contact unit is in communication with the sulfuric acid solution inlet.

15. The apparatus of claim 14, wherein the phosphorus pentafluoride is generated by the reaction of phosphorus trichloride and hydrogen fluoride. The device further comprises a second atomization unit and a cracking unit, the bottom outlet of the contact unit is further in communication with the inlet of the second atomization unit, the outlet of the second atomization unit is in communication with the inlet of the cracking unit.