Production device of high-purity red phosphorus

Abstract

The utility model relates to a high-purity red phosphorus production device which comprises a stainless steel sealed pressure container, an infrared electric heater is arranged in the stainless steel sealed pressure container, an outer-layer high-purity quartz tube is arranged in the infrared electric heater, an inner-layer high-purity quartz tube is arranged in the outer-layer high-purity quartz tube, and an inner-layer high-purity quartz tube is arranged in the inner-layer high-purity quartz tube. Two ends of the inner layer high-purity quartz tube are closed, through holes are formed in the circumferential surface of the inner layer high-purity quartz tube, one end of the outer layer high-purity quartz tube is closed, and the other end of the outer layer high-purity quartz tube is provided with an opening which is hermetically connected with a stainless steel tube joint which is respectively connected with a nitrogen system and a vacuum system after extending out of an end socket of the stainless steel sealed pressure vessel; the stainless steel sealed pressure container is further provided with a nitrogen charging and discharging port which is connected with a nitrogen system. According to the utility model, the nested inner-layer high-purity quartz tube and the nested outer-layer high-purity quartz tube are adopted, discharging is carried out in the inner-layer high-purity quartz tube, red phosphorus is convenient to take out, nitrogen is filled inside and outside the outer-layer high-purity quartz tube, pressure balance inside and outside the outer-layer high-purity quartz tube is kept, and safety is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of preparation of elemental phosphorus, in particular to a production device for high-purity red phosphorus. Background Art

[0002] High-purity red phosphorus can be used to synthesize semiconductor materials such as indium phosphide (InP), gallium phosphide (GaP), aluminum gallium arsenide phosphide (AlGaAsP), indium gallium arsenide phosphide (InGaAsP), and gallium arsenide phosphide (GaAsP). These materials offer advantages such as high electron mobility, high frequency response, and low noise, making them key components of high-performance electronic and optoelectronic devices.

[0003] At present, the method of producing high-purity red phosphorus is basically to directly convert yellow phosphorus (white phosphorus) into red phosphorus. The conversion forms are roughly divided into two types:

[0004] 1. High-pressure conversion: Patent CN101214935B discloses a "production process for electronic-grade red phosphorus." High-purity yellow phosphorus is transferred to a conversion pot and filled with 1-2 kg of inert gas at 20°C-80°C, 2-4 kg of inert gas at 80°C-200°C, no inert gas at 200°C-250°C, 1-2 kg of inert gas at 250°C-280°C, and 1-2 kg of inert gas at 280°C-300°C. The pot is then naturally cooled to room temperature to obtain a 99.9999% high-purity red phosphorus product. However, this method has relatively high equipment requirements, and the high-pressure conditions also pose safety risks.

[0005] 2. Atmospheric pressure conversion: In the latest technology of converting yellow phosphorus into high-purity red phosphorus at atmospheric pressure, patent number CN109081320A discloses "a device and method for converting electronic grade high-purity yellow phosphorus into red phosphorus". The device consists of a converter, a heater, a temperature controller, a condenser, and an exhaust water seal. The method is as follows: (1) high-purity yellow phosphorus is placed in the converter, covered with ultra-high purity water, and the converter is heated until the water is completely evaporated; (2) warm water is continuously introduced into the condenser to condense the yellow phosphorus vapor, and the heater is controlled to slowly heat the converter to 350°C, and then the temperature is controlled within 350°C to 370°C for 24 hours; (3) after the yellow phosphorus is completely converted into red phosphorus, the heating is stopped and the temperature is naturally cooled. At the same time, inert gas is introduced into the converter. After it cools to room temperature, the converter is placed in pure water and the converter is broken to obtain red phosphorus. This method has losses during the reaction process, and the yield of high-purity red phosphorus is not high, at around 92%. Under the same conversion efficiency, the time is long or the conversion is not complete, and post-processing such as alkaline solution purification and washing is required to ensure quality. Utility Model Content

[0006] The purpose of the utility model is to overcome the above-mentioned shortcomings and provide a high-purity red phosphorus production device, which can realize the batch production of high-purity red phosphorus of 6N (99.9999%) to 9N (99.999999%) grades, effectively stabilize the quality of red phosphorus products, maintain high yield requirements, reduce safety risks, have strong operability, reliable system and relatively low cost.

[0007] The purpose of this utility model is achieved in this way:

[0008] A high-purity red phosphorus production device comprises a stainless steel sealed pressure vessel, an infrared electric heater, an outer high-purity quartz tube, an inner high-purity quartz tube, a nitrogen system and a vacuum system. The stainless steel sealed pressure vessel is equipped with a built-in infrared electric heater, the infrared electric heater is equipped with an outer high-purity quartz tube, the outer high-purity quartz tube is equipped with an inner high-purity quartz tube, both ends of the inner high-purity quartz tube are closed, and two through holes are provided on the circumferential surface. One end of the outer high-purity quartz tube is closed, and the other end is equipped with an opening for the inner high-purity quartz tube to enter. The opening is sealed and connected to a stainless steel pipe joint. The stainless steel pipe joint extends out of the sealing head of the stainless steel sealed pressure vessel and is respectively connected to the nitrogen system and the vacuum system. The stainless steel sealed pressure vessel is also equipped with a nitrogen charging and discharging port, and the nitrogen charging and discharging port is connected to the nitrogen system.

[0009] Preferably, the nitrogen system includes a nitrogen buffer tank and a nitrogen bottle, the vacuum system includes a vacuum buffer tank and a vacuum pump, the nitrogen bottle is connected to the nitrogen buffer tank, the nitrogen buffer tank is respectively connected to the nitrogen charging and discharging port and the stainless steel pipe joint through pipelines, and the stainless steel pipe joint is also connected in parallel to the vacuum buffer tank.

[0010] Preferably, the vacuum buffer tank is connected to the exhaust buffer tank via a vacuum pump, and the exhaust vacuum tank is provided with an exhaust port and a nitrogen replenishing port, and the nitrogen replenishing port is connected to the nitrogen buffer tank.

[0011] Preferably, the infrared electric heater, the outer high-purity quartz tube, and the inner high-purity quartz tube are all concentrically arranged.

[0012] Preferably, the stainless steel sealed pressure vessel is provided with a cooling jacket, and circulating cooling water is provided in the jacket, and the circulating cooling water is provided by a circulating water system.

[0013] Preferably, the wires of the infrared electric heater extend out of a stainless steel sealed pressure vessel and are sealed and insulated by a wire sealing and heat-insulating assembly.

[0014] Preferably, the wire sealing and insulation assembly includes an air-cooling connector, a stainless steel sheath and a stainless steel capillary tube. The stainless steel sealed pressure vessel is provided with a flange corresponding to the wire of the infrared electric heater. The air-cooling connector is sealed and connected to the flange of the stainless steel sealed pressure vessel. The air-cooling connector is connected to the stainless steel sheath. Three stainless steel capillary tubes are provided in the stainless steel sheath. A porcelain tube with a built-in wire is provided in the stainless steel capillary tube. One end of the stainless steel capillary tube is welded to the air-cooling connector, and the other end is fixed by pouring high-temperature resin. A water-cooling cavity is formed between the high-temperature resin in the stainless steel sheath and the air-cooling connector. Circulating cooling water is provided in the water-cooling cavity, and the circulating cooling water is provided by a circulating water system.

[0015] The beneficial effects of the utility model are:

[0016] 1. It can achieve the conversion of white phosphorus under relatively high pressure. At the same time, it can balance the heated quartz tube and its connecting seals at a high temperature of 350°C by adjusting the nitrogen filling and releasing method through the internal and external pressure differential control, thereby reducing the risk of seal failure and leakage caused by high internal pressure.

[0017] 2. By adding sufficient nitrogen pressure into the outer high-purity quartz tube, the boiling point of white phosphorus can be raised, preventing it from volatilizing at the boiling point of 280°C to produce white phosphorus vapor. As a result, the gaseous white phosphorus overflows the inner high-purity quartz tube during conversion and enters the outer high-purity quartz tube for conversion, reducing the need to clean the red phosphorus in the outer high-purity quartz tube and improving the overall yield of the finished red phosphorus.

[0018] 3. Installing a stainless steel sealed pressure vessel outside the infrared electric heater can prevent the safety risk of white phosphorus liquid or gas leakage caused by quartz tube aging and cracking due to thermal expansion and contraction;

[0019] 4. Infrared heating is used, which has precise temperature control and can heat without conventional conduction without physical contact. The characteristic of infrared heating is that radiation heat transfer is the main method, accounting for about 90%. By mainly using radiation heat transfer, heat is transferred to the inner layer of high-purity quartz tube, making the design of inner and outer layer high-purity quartz tube possible; when discharging, only the low-cost inner layer high-purity quartz tube needs to be broken, and the high-cost outer layer high-purity quartz tube can be reused, which greatly reduces the equipment cost;

[0020] 5. The wires of the infrared electric heater extend out of the stainless steel sealed pressure vessel and are sealed and insulated through the wire sealing and insulation components to ensure the sealing and safety of the container. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The utility model is a structural schematic diagram of a high-purity red phosphorus production device.

[0022] Figure 2This is a schematic diagram of the assembly structure of the stainless steel sealed pressure vessel of the present utility model.

[0023] Figure 3 Schematic diagram of the assembly structure of the wire sealing and insulation component.

[0024] Figure 4 This is a production process flow chart of the utility model.

[0025] Wherein: stainless steel sealed pressure vessel 1; nitrogen filling and discharging port 1.1; head 1.2; infrared electric heater 2; outer high-purity quartz tube 3; inner high-purity quartz tube 4; through hole 4.1; stainless steel pipe joint 5; nitrogen buffer tank 6; nitrogen bottle 7; vacuum buffer tank 8; vacuum pump 9; exhaust buffer tank 10; wire sealing and insulation assembly 11; air-cooling connector 11.1; stainless steel sheath 11.2; stainless steel capillary tube 11.3; porcelain tube 11.4; high-temperature resin 11.5; cable external interface plug 11.6; cooling water tank 12; circulating water pump 13; fixed base 14. DETAILED DESCRIPTION

[0026] See also Figure 1-4 The utility model relates to a production device for high-purity red phosphorus, comprising a stainless steel sealed pressure vessel 1, an infrared electric heater 2, an outer high-purity quartz tube 3, an inner high-purity quartz tube 4, a nitrogen system, a vacuum system and a circulating water system. The stainless steel sealed pressure vessel 1 is equipped with an infrared electric heater 2, an outer high-purity quartz tube 3 is arranged inside the infrared electric heater 2, an inner high-purity quartz tube 4 is arranged inside the outer high-purity quartz tube 3, the infrared electric heater 2, the outer high-purity quartz tube 3 and the inner high-purity quartz tube 4 are all concentrically arranged, the inner high-purity quartz tube 4 is cylindrical, both ends of the inner high-purity quartz tube 4 are closed, and two through holes 4.1 are provided on the circumferential surface, the through holes have two functions, one is to ventilate and balance the pressure; the other is for high-purity white phosphorus and high-purity water to enter the inner high-purity quartz tube 4, the wall thickness of the inner high-purity quartz tube 4 is 2-6 mm, and it does not bear pressure.

[0027] The outer high-purity quartz tube 3 is also cylindrical, with a wall thickness of 6 mm to 20 mm. It needs to withstand pressure, has high cost, and can be reused many times. One end of the outer high-purity quartz tube 3 is closed, and the other end is provided with an opening for the inner high-purity quartz tube 4 to enter. The opening is sealed and connected to a stainless steel pipe joint 5. The stainless steel pipe joint 5 extends out of the head 1.2 of the stainless steel sealed pressure vessel 1 and is respectively connected to the nitrogen system and the vacuum system. The gap between the stainless steel pipe joint 5 and the stainless steel sealed pressure vessel 1 is sealed.

[0028] The stainless steel sealed pressure vessel 1 is further provided with a nitrogen charging and discharging port 1.1, and the nitrogen charging and discharging port 1.1 is connected to a nitrogen system.

[0029] The nitrogen system includes a nitrogen buffer tank 6 and a nitrogen bottle 7. The vacuum system includes a vacuum buffer tank 8, a vacuum pump 9 and an exhaust buffer tank 10. The nitrogen bottle 7 is connected to the nitrogen buffer tank 6. The nitrogen buffer tank 6 is respectively connected to the nitrogen charging and discharging port 1.1 and the stainless steel pipe joint 5 through pipelines. The stainless steel pipe joint 5 is also connected to the vacuum buffer tank 8 in parallel. The vacuum buffer tank 8 is used to collect condensed water vapor. The vacuum buffer tank 8 is connected to the exhaust buffer tank 10 through the vacuum pump 9. The exhaust vacuum tank 10 is provided with an exhaust port and a nitrogen replenishing port. The nitrogen replenishing port is connected to the nitrogen buffer tank 6. The nitrogen buffer tank 6 continuously releases nitrogen to the exhaust vacuum tank 10 to ensure that there is sufficient nitrogen in the exhaust buffer tank and prevent the risk of air backflow caused by return air backflow due to abnormal stop or operation of the vacuum pump.

[0030] The wires of the infrared electric heater 2 extend out of the stainless steel sealed pressure vessel 1 and are sealed and insulated by a wire sealing and heat-insulating assembly 11. The wire sealing and heat-insulating assembly 11 includes an air-cooling connector 11.1, a stainless steel sheath 11.2 and a stainless steel capillary 11.3. The stainless steel sealed pressure vessel 1 is provided with a flange corresponding to the wires of the infrared electric heater 2. The air-cooling connector 11.1 is sealedly connected to the flange of the stainless steel sealed pressure vessel 1. The air-cooling connector 11.1 is connected to the stainless steel sheath 11.2. Three stainless steel capillary 11.3 are provided in the stainless steel sheath 11.2. One end of the stainless steel capillary 11.3 is welded to the air-cooling connector 11.1, and the other end is fixed by pouring a high-temperature resin 11.5. The stainless steel capillary 11.3 is welded to the air-cooling connector 11.1. A porcelain tube 11.4 is provided in the steel capillary tube 11.3, and a conductor is provided in the porcelain tube 11.4. The porcelain tube 11.4 for passing the conductor isolates the conductor from contact with the stainless steel sheath and the stainless steel capillary tube, thereby preventing the conductor from contacting the stainless steel and causing a short circuit and other dangerous conditions. The conductor is connected to an external cable interface plug 11.6 through the porcelain tube 11.4. The three conductors in the external cable interface plug 11.6 are combined into one and then connected to an external power supply. A water-cooling chamber is formed between the high-temperature resin 11.5 in the stainless steel sheath 11.2 and the air-cooling connector 11.1. Circulating cooling water is provided in the water-cooling chamber. Water cooling prevents high-temperature gas and heat generated by heating inside the stainless steel sealed pressure vessel from being transferred to one end of the high-temperature resin, thereby effectively preventing thermal damage to the high-temperature resin and sealing failure.

[0031] The stainless steel sealed pressure vessel 1 is provided with a cooling jacket, and circulating water is provided in the jacket to facilitate cooling after the conversion of high-purity white phosphorus is completed.

[0032] The circulating water system simultaneously cools the wire sealing and insulation assembly 11 and the stainless steel sealed pressure vessel. The circulating water system includes a cooling water tank 12 and a circulating water pump 13. The circulating water in the cooling water tank 12 is pumped by the circulating water pump 13 to the jacket of the stainless steel sealed pressure vessel 1 and the water cooling cavity of the wire sealing and insulation assembly 11, respectively, and then flows into the cooling water tank 12 after heat exchange.

[0033] The stainless steel sealed pressure container 1 is cylindrical and placed horizontally. A fixed base 14 is provided at the bottom of the stainless steel sealed pressure container 1 .

[0034] The infrared electric heater 2 mainly uses radiation heat transfer to conduct heat to the inner high-purity quartz tube, making it possible to design high-layer quartz tubes in the inner and outer layers. The infrared electric heater is equipped with a temperature controller, which can accurately control the temperature rise and the white phosphorus conversion temperature. The temperature rise range and temperature rise speed or staged temperature rise can be freely adjusted.

[0035] A method for producing high-purity red phosphorus comprises the following steps:

[0036] Step 1: Place measured high-purity white phosphorus with a purity of 6N-9N into the inner high-purity quartz tube 4. For safe operation, the high-purity white phosphorus is covered with high-purity water. The high-purity water and high-purity white phosphorus enter through the through hole 4.1, which is set upward.

[0037] The inner high-purity quartz tube is first filled with some high-purity hot water through a feeding system to a position of one-third of its volume, and the temperature of the high-purity hot water is controlled at 60°C-80°C. The through hole of the inner high-purity quartz tube is then inserted into the feeding tube to below the liquid level of the high-purity hot water, and a measured amount of liquid high-purity white phosphorus is injected. The inner high-purity quartz tube with white phosphorus is then placed in water at a temperature of 20°C to cool and solidify the white phosphorus. After the liquid white phosphorus solidifies, the inner high-purity quartz tube is inserted into the outer high-purity quartz tube, and a stainless steel pipe joint is installed in the outer high-purity quartz tube. At the same time, the outer high-purity quartz tube is inserted into the infrared electric heater, and the infrared electric heater is inserted into a stainless steel sealed pressure vessel and a head is installed.

[0038] Step 2: Using a vacuum system and a nitrogen system, evacuate and inject nitrogen into the outer high-purity quartz tube. Replace the air in the outer high-purity quartz tube with nitrogen in 3-4 steps to reduce the oxygen content in the outer high-purity quartz tube to less than 100 ppm. Activate an infrared electric heater to preheat the high-purity white phosphorus in the inner high-purity quartz tube. Slowly increase the temperature (20°C / hour) to 80°C-90°C, then stop heating to liquefy the high-purity white phosphorus. Activate a vacuum pump to evacuate the tube. The vacuum degree can be controlled at 200 mmHg-400 mmHg. Gradually evaporate the moisture on the surface of the white phosphorus until the vacuum degree reaches above 730 mmHg. Nitrogen is then added to return the pressure in the inner quartz tube to normal pressure.

[0039] Step 3: Continue to slowly raise the temperature (30°C / hour) to 120°C-150°C, and vacuumize again until the vacuum degree reaches 730 mmHg or more, maintain for about 15 minutes, then add nitrogen, vacuumize again and replace with nitrogen two to three times. After replacement, fill the outer high-purity quartz tube with nitrogen and slowly increase the pressure to 0.2MPa-0.5MPa, then close the nitrogen valve. While increasing the pressure in the outer high-purity quartz tube, simultaneously introduce nitrogen through the nitrogen filling and discharging port 1.1 of the stainless steel sealed pressure vessel 1, maintain the positive pressure difference between the inside and outside of the outer high-purity quartz tube at 0.05MPa-0.10MPa, and then continue to slowly raise the temperature in stages until the temperature reaches 350°C-380°C;

[0040] By regulating the internal and external pressures, an operating pressure of at least 0.2 MPa to 0.5 MPa is maintained in the inner high-purity quartz tube to increase the boiling point of white phosphorus, thereby reducing the accumulation of white phosphorus on the inner wall of the outer high-purity quartz tube 3 after volatilization from the inner high-purity quartz tube 4. This reduces the need to clean up the broken red phosphorus formed on the inner wall of the outer high-purity quartz tube in the later stage and reduces the amount of finished red phosphorus.

[0041] The temperature starts to rise from about 150°C to the range of 350°C-380°C, and the time lasts for about 40 hours. The heating is suspended twice during this period. Specifically, the heating rate is controlled at a temperature rise of 2°C to 3°C per hour. When the temperature rises to 265°C, the heating is suspended. At this time, the white phosphorus in the inner quartz tube will automatically start to heat up for a period of time due to conversion to red phosphorus. After the automatic temperature rise ends, wait for the temperature to stabilize for 20 minutes, and then continue to slowly heat up to 285°C. The heating is suspended for the second time and maintained for 20 minutes to observe whether the temperature continues to rise. After the temperature is constant, the infrared heating is continued, and the heating rate is controlled to be 2°C per hour, until the temperature reaches 330°C and maintained for 2 hours, and then the temperature is raised to 350°C and maintained for 3 hours.

[0042] Step 4: After the heating is completed, cool naturally for about 5 hours. When the temperature drops to below 250°C, start forced cooling and discharging of the stainless steel sealed pressure vessel;

[0043] The circulating water pump is started, and circulating water enters and exits the jacket of the stainless steel sealed pressure vessel to cool the temperature. As the temperature drops, the pressure differential between the inside and outside of the outer high-purity quartz tube changes. At this time, nitrogen is automatically released or replenished through the coordinated cooperation of two automatic control regulating valves, so that the pressure differential between the inside and outside of the quartz tube can be always controlled within a pressure differential of 0.1 MPa. After the system temperature drops to room temperature, the stainless steel sealed pressure vessel is opened, and the outer and inner high-purity quartz tubes are simultaneously removed and placed in a high-purity water container under the water surface to isolate them from the air. The inner high-purity quartz tube 4 is broken underwater to obtain a block of high-purity red phosphorus. The block of high-purity red phosphorus is cut into small particles using a special tool, removed and placed in a vacuum drying oven under nitrogen protection at above 80°C for drying. After drying, the high-purity red phosphorus is weighed and packaged, and then packaged in brown clean glass containers or special bottles under nitrogen protection for storage. After passing the test, it can be sold. Example 1

[0044] A method for producing high-purity red phosphorus comprises the following steps:

[0045] (1) Place 6 kg of high-purity yellow phosphorus with a purity of 6N-9N in an inner high-purity quartz tube and cover it with ultra-high-purity water. After cooling and solidification, the inner high-purity quartz tube containing solid white phosphorus is installed in the outer high-purity quartz tube and all pipelines are sealed and connected. After the system pressure test and leak test are normal, turn on the vacuum pump, connect the outer high-purity quartz tube and evacuate it four times, and replace it with high-purity nitrogen four times to reduce the air in the outer high-purity quartz tube to less than 100PPm, then add nitrogen to normal pressure, turn on the infrared heater to heat the temperature in the outer high-purity quartz tube to 85℃, then stop heating, and turn on the vacuum pump to evacuate until the water on the upper part of the white phosphorus in the outer high-purity quartz tube is completely evaporated and the vacuum degree rises to a level that no longer rises;

[0046] (2) Add nitrogen to the inside of the quartz tube to maintain normal pressure, continue to turn on the infrared heater to slowly raise the temperature of the white phosphorus in the quartz tube to 130°C, and start the vacuum pump again to completely evaporate any bound water that may exist in the system and any water vapor that may exist in the bottom area of the white phosphorus;

[0047] (3) High-purity nitrogen is introduced again, and the pressure of high-purity nitrogen is inflated to 0.3 MPa. At the same time, the pressure of the nitrogen outside the outer quartz tube is supplemented to offset the internal pressure, so as to balance and control the pressure difference between the inner and outer layers of the outer quartz tube to operate at a relatively low pressure difference. The pressure difference control method can be controlled by automatic control;

[0048] (4) After the nitrogen filling is completed, the temperature control system is turned on to increase the temperature. The temperature rise rate is controlled at 8°C per hour. When the temperature reaches 265°C, the temperature rise is stopped. At this time, the white phosphorus in the inner quartz tube will automatically rise in temperature for a period of time due to the conversion to red phosphorus. After the automatic temperature rise is completed, the temperature is slowly raised to 290°C. The temperature rise rate is controlled at 8°C per hour. The heating is stopped and maintained for 30 minutes to observe whether the temperature continues to rise. After the temperature is constant, the infrared heating gas is turned on to increase the temperature. The heating rate is controlled at 5°C per hour until the temperature reaches 330°C and maintained for 2 hours, and then the temperature is raised to 350°C and maintained for 2 hours. Then the heating is stopped and the temperature is naturally cooled for about 3 hours. The material is then discharged at a lower temperature.

[0049] (5) During the cooling operation, when the temperature in the jacket is lower than 250℃, start the water pump and control the jacket to slowly enter the water to prevent the jacket from cooling rapidly and causing uneven stress on the shell. The cooling water tank should be properly replenished with fresh cooling water. After cooling to room temperature, the container can be opened, the quartz tube can be disassembled, and the inner high-purity quartz tube containing red phosphorus can be taken out. It can be placed in high-purity water for further cooling, and then the quartz tube can be broken to take out the red phosphorus. The red phosphorus can be cut into small particles underwater with a special tool and taken out. It can be placed in a vacuum drying system to dry, and then weighed and packaged in a brown clean glass container protected by nitrogen to obtain 5.95 kg of high-purity red phosphorus.

[0050] After product sampling and processing, it was tested by a professional testing agency. The test and analysis results of impurity content are shown in Table 1.

[0051] Table 1 Impurity content analysis results of Example 1 (unit: ppb, ND means not detected)

[0052]

[0053] It can be seen that the quality of the product obtained by the method of the present invention fully meets the quality requirements of red phosphorus required for compound semiconductors such as indium phosphide (InP) and gallium phosphide (GaP). Example 2

[0054] A method for producing high-purity red phosphorus comprises the following steps:

[0055] (1) Place 8 kg of high-purity yellow phosphorus with a purity of 6N-9N in an inner high-purity quartz tube and cover it with ultra-high-purity water. After cooling and solidification, the inner high-purity quartz tube containing solid white phosphorus is installed in the outer high-purity quartz tube and all pipelines are sealed and connected. After the system pressure test and leak test are normal, turn on the vacuum pump, connect the outer high-purity quartz tube and evacuate it four times, and replace it with high-purity nitrogen four times to reduce the air in the outer high-purity quartz tube to less than 100PPm, then add nitrogen to normal pressure, turn on the infrared heater to heat the temperature in the outer high-purity quartz tube to 90℃, then stop heating, and turn on the vacuum pump to evacuate until the water on the upper part of the white phosphorus in the outer high-purity quartz tube is completely evaporated and the vacuum degree rises to a level that no longer rises;

[0056] (2) Nitrogen is added to the quartz tube to maintain normal pressure. The infrared heater is continued to be turned on to slowly raise the temperature of the white phosphorus in the quartz tube to 150°C. The vacuum pump is then started again to completely evaporate any bound water that may exist in the system and any water vapor that may exist in the bottom area of the white phosphorus.

[0057] (3) High-purity nitrogen is introduced again, and the pressure of high-purity nitrogen is inflated to 0.3 MPa. At the same time, the pressure of the nitrogen outside the outer quartz tube is supplemented to offset the internal pressure, so as to balance and control the pressure difference between the inner and outer layers of the outer quartz tube to operate at a relatively low pressure difference. The pressure difference control method can be controlled by automatic control;

[0058] (4) After the nitrogen filling is completed, the temperature control system is turned on to increase the temperature. The temperature rise rate is controlled at 9°C per hour. When the temperature reaches 265°C, the temperature rise is stopped. At this time, the white phosphorus in the inner quartz tube will automatically rise in temperature for a period of time due to the conversion to red phosphorus. After the automatic temperature rise is completed, the temperature is slowly raised to 290°C. The temperature rise rate is controlled at 9°C per hour. The heating is stopped and maintained for 30 minutes to observe whether the temperature continues to rise. After the temperature is constant, the infrared heating gas is turned on to increase the temperature. The heating rate is controlled at 6°C per hour until the temperature reaches 330°C and maintained for 2 hours, and then the temperature is raised to 350°C and maintained for 1 hour. Then the heating is stopped and the temperature is naturally cooled for about 3 hours. The material is then discharged at a lower temperature.

[0059] (5) During the cooling operation, when the temperature in the jacket is lower than 250℃, start the water pump and control the jacket to slowly enter water to prevent the jacket from cooling rapidly and causing uneven stress on the shell. The cooling water tank should be properly replenished with fresh cooling water. After cooling to room temperature, the container can be opened, the quartz tube can be disassembled, and the inner high-purity quartz tube containing red phosphorus can be taken out. It can be placed in high-purity water for further cooling, and then the quartz tube can be broken to take out the red phosphorus. The red phosphorus can be cut into small particles underwater with a special tool and taken out. It can be placed in a vacuum drying system to dry, and then weighed and divided into brown clean glass containers protected by nitrogen for storage, to obtain 7.9 kg of high-purity red phosphorus.

[0060] After product sampling and processing, it was tested by a professional testing agency. The test and analysis results of impurity content are shown in Table 2.

[0061] Table 2 Impurity content analysis results of Example 2 (unit: ppb, ND means not detected)

[0062]

[0063] It can be seen that the quality of the product obtained by the method of the present invention fully meets the quality requirements of red phosphorus required for compound semiconductors such as indium phosphide (InP) and gallium phosphide (GaP). Example 3

[0064] A method for producing high-purity red phosphorus comprises the following steps:

[0065] (1) Place 10 kg of high-purity yellow phosphorus with a purity of 6N-9N in an inner high-purity quartz tube and cover it with ultra-high-purity water. After cooling and solidification, the inner high-purity quartz tube containing solid white phosphorus is installed in the outer high-purity quartz tube and all pipelines are sealed and connected. After the system pressure test and leak test are normal, turn on the vacuum pump, connect the outer high-purity quartz tube and evacuate it four times. At the same time, replace it with high-purity nitrogen four times to reduce the air in the outer high-purity quartz tube to less than 100PPm, then add nitrogen to normal pressure, turn on the infrared heater to heat the temperature in the outer high-purity quartz tube to 86℃, then stop heating, and turn on the vacuum pump to evacuate until the water on the upper part of the white phosphorus in the outer high-purity quartz tube is completely evaporated and the vacuum degree rises to a level that no longer rises;

[0066] (2) Add nitrogen to the inside of the quartz tube to maintain normal pressure, continue to turn on the infrared heater to slowly raise the temperature of the white phosphorus in the quartz tube to 145°C, and start the vacuum pump again to completely evaporate any bound water that may exist in the system and any water vapor that may exist in the bottom area of the white phosphorus;

[0067] (3) High-purity nitrogen is introduced again, and the pressure of high-purity nitrogen is inflated to 0.3 MPa. At the same time, the pressure of the nitrogen outside the outer quartz tube is supplemented to offset the internal pressure, so as to balance and control the pressure difference between the inner and outer layers of the outer quartz tube to operate at a relatively low pressure difference. The pressure difference control method can be controlled by automatic control;

[0068] (4) After the nitrogen filling is completed, the temperature control system is turned on to increase the temperature. The temperature rise rate is controlled at 10°C per hour. When the temperature reaches 270°C, the temperature rise is stopped. At this time, the white phosphorus in the inner quartz tube will automatically rise in temperature for a period of time due to the conversion to red phosphorus. After the automatic temperature rise is completed, the temperature is slowly raised to 295°C. The temperature rise rate is controlled at 10°C per hour. The heating is stopped and maintained for 30 minutes to observe whether the temperature continues to rise. After the temperature is constant, the infrared heating gas is turned on to increase the temperature. The heating rate is controlled at 8°C per hour until the temperature reaches 330 degrees and maintained for 3 hours. Then the temperature is raised to 350°C and maintained for 1 hour. Then the heating is stopped and the temperature is naturally cooled for about 2.5 hours. The material is then discharged at a lower temperature.

[0069] (5) During the cooling operation, when the temperature in the jacket is lower than 250℃, start the water pump and control the jacket to slowly enter the water to prevent the jacket from cooling rapidly and causing uneven stress on the shell. The cooling water tank should be properly replenished with fresh cooling water. After cooling to room temperature, the container can be opened, the quartz tube can be disassembled, and the inner high-purity quartz tube containing red phosphorus can be taken out. It can be placed in high-purity water for further cooling, and then the quartz tube can be broken to take out the red phosphorus. The red phosphorus can be cut into small particles underwater with a special tool and taken out. It can be placed in a vacuum drying system to dry, and then weighed and divided into brown clean glass containers protected by nitrogen for storage, to obtain 9.85 kg of high-purity red phosphorus.

[0070] After product sampling and processing, it was tested by a professional testing agency. The test and analysis results of impurity content are shown in Table 3.

[0071] Table 3 Impurity content analysis results of Example 3 (unit: ppb, ND means not detected)

[0072]

[0073] It can be seen that the quality of the product obtained by the method of the present invention fully meets the quality requirements of red phosphorus required for compound semiconductors such as indium phosphide (InP) and gallium phosphide (GaP).

[0074] In addition to the above embodiments, the present invention also includes other implementation methods. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of protection of the claims of the present invention.

Claims

1. A production device for high-purity red phosphorus, characterized in that: The invention comprises a stainless steel sealed pressure vessel, an infrared electric heater, an outer high-purity quartz tube, an inner high-purity quartz tube, a nitrogen system and a vacuum system. The stainless steel sealed pressure vessel is equipped with a built-in infrared electric heater, an outer high-purity quartz tube is arranged inside the infrared electric heater, an inner high-purity quartz tube is arranged inside the outer high-purity quartz tube, both ends of the inner high-purity quartz tube are closed, and a through hole is arranged on the circumferential surface. One end of the outer high-purity quartz tube is closed, and the other end is provided with an opening for the inner high-purity quartz tube to enter. The opening is sealed and connected to a stainless steel pipe joint. The stainless steel pipe joint extends out of the sealing head of the stainless steel sealed pressure vessel and is respectively connected to the nitrogen system and the vacuum system. The stainless steel sealed pressure vessel is also provided with a nitrogen charging and discharging port, and the nitrogen charging and discharging port is connected to the nitrogen system.

2. A high-purity red phosphorus production device according to claim 1, characterized in that: The nitrogen system includes a nitrogen buffer tank and a nitrogen bottle, and the vacuum system includes a vacuum buffer tank and a vacuum pump. The nitrogen bottle is connected to the nitrogen buffer tank, and the nitrogen buffer tank is respectively connected to the nitrogen charging and discharging port and the stainless steel pipe joint through pipelines. The stainless steel pipe joint is also connected in parallel to the vacuum buffer tank.

3. A production device for high-purity red phosphorus according to claim 2, characterized in that: The vacuum buffer tank is connected to the exhaust buffer tank through a vacuum pump. The exhaust buffer tank is provided with an exhaust port and a nitrogen replenishing port, and the nitrogen replenishing port is connected to the nitrogen buffer tank.

4. The production device of high-purity red phosphorus according to claim 1, characterized in that: The infrared electric heater, the outer high-purity quartz tube, and the inner high-purity quartz tube are all concentrically arranged.

5. The production device of high-purity red phosphorus according to claim 1, characterized in that: The stainless steel sealed pressure vessel is provided with a cooling jacket, and circulating cooling water is provided in the jacket, and the circulating cooling water is provided by a circulating water system.

6. The production device of high-purity red phosphorus according to claim 1, characterized in that: The wire of the infrared electric heater extends out of the stainless steel sealed pressure container and is sealed and insulated by a wire sealing and heat-insulating assembly.

7. The production device of high-purity red phosphorus according to claim 6, characterized in that: The wire sealing and insulation assembly includes an air-cooling connector, a stainless steel sheath and a stainless steel capillary tube. The stainless steel sealed pressure vessel is provided with a flange corresponding to the wire of the infrared electric heater. The air-cooling connector is sealed and connected to the flange of the stainless steel sealed pressure vessel. The air-cooling connector is connected to the stainless steel sheath. Three stainless steel capillary tubes are provided in the stainless steel sheath. A porcelain tube with a built-in wire is provided in the stainless steel capillary tube. One end of the stainless steel capillary tube is welded to the air-cooling connector, and the other end is fixed by pouring high-temperature resin. A water-cooling cavity is formed between the high-temperature resin in the stainless steel sheath and the air-cooling connector. Circulating cooling water is provided in the water-cooling cavity, and the circulating cooling water is provided by a circulating water system.

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