Method for purifying electronic-grade yellow phosphorus by multi-stage series microreactor-rectification-adsorption system

Abstract

The invention discloses a method for purifying electronic-grade yellow phosphorus through a multi-stage series microreactor-rectification-adsorption system, and belongs to the technical field of phosphorus chemical industry. The invention discloses a yellow phosphorus continuous purification process which takes industrial-grade yellow phosphorus as a raw material and is subjected to hydrogen peroxide continuous oxidation in a micro-channel, halogenated hydrocarbon continuous extraction in the micro-channel, water washing, alkali washing, rectification in a rectifying tower and adsorption in an adsorption tower, and belongs to the field of yellow phosphorus purification. According to the method, the temperature in the reaction process is accurately controlled by utilizing the characteristics of high mass transfer and high heat transfer of the micro-channel reactor, and an efficient continuous production process is formed by combining a multi-stage purification unit. The process is mild in condition, short in reaction time, safe and stable in reaction process, continuous in production, high in impurity removal rate and high in production efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of phosphorus chemical industry and relates to a production method for purifying electronic-grade yellow phosphorus. The method uses yellow phosphorus-high pure water as raw materials, hydrogen peroxide-oxidation enhancer (potassium dichromate) as oxidants, and performs enhanced oxidation reaction and halogenated hydrocarbon extraction in a microchannel reactor. Subsequently, the obtained product is subjected to water washing, rectification, and adsorption steps to remove impurities. The purification method of the present invention has low cost, safe operation, is conducive to industrialization, and has good economic benefits. Background Art

[0002] Yellow phosphorus is a key raw material in the phosphorus chemical industry, especially for high-purity phosphorus chemicals, and its application scope is very wide. In the field of the electronics industry, materials such as InP and GaP play important roles and are indispensable dopants in the production of planar epitaxial transistors and integrated circuits. In the petrochemical industry, high-purity PCl3 and P2O5 are used as additives for high-grade lubricating oils. In the pharmaceutical field, high-purity phosphorus is a raw material for the production of various drugs such as immunosuppressants, vasodilator drugs, and drugs for improving brain metabolism. In addition, high-purity phosphorus is widely used in multiple fields such as the food industry, automobile manufacturing, military industry, and aviation. It is inevitable that yellow phosphorus products are mixed with impurities such as arsenic, organic matter, silicon, sulfur, iron, and metals, which will greatly limit their applications. Therefore, the purification of yellow phosphorus is particularly important. However, due to the special properties of yellow phosphorus itself, considering aspects such as safety, economy, reaction conditions, and processes, the industrial yellow phosphorus purification technology is difficult, and many purification methods have not been industrialized.

[0003] However, industrial yellow phosphorus contains various trace impurities, especially the enrichment of arsenic. As a highly toxic substance, arsenic must be effectively removed from yellow phosphorus.

[0004] The main methods for purifying yellow phosphorus reported in the existing processes are as follows: (1) Chemical method, generally used for the refining and purification of low-arsenic yellow phosphorus, with high arsenic and antimony removal rates, but it is difficult to remove the impurity ions brought in by the reagents during the refining process. Among them, the aqueous phase oxidation method in China has developed most rapidly in the chemical refining method; (2) Physical method, which separates based on the physical properties between phosphorus and arsenic, including zone melting method, distillation method, and adsorption method.

[0005] Patent CN 109607501 A proposes a purification method using hydrogen peroxide and arsenic removal adsorbent, nitric acid and oxidation enhancer, and iron removal adsorbent. This method can remove arsenic and iron in yellow phosphorus. However, a large amount of waste liquid of mixed acids such as nitric acid and phosphoric acid will be generated in this method; the use of multiple adsorbents increases the production cost, the operation is complex, and it is difficult to achieve industrial scale-up.

[0006] The traditional processes for purifying electronic-grade yellow phosphorus at home and abroad currently have the following main scientific problems: (1) The mechanism of directional migration of arsenic elements is unclear, and the impurity removal efficiency is low. Arsenic and phosphorus will form As-P covalent bonds, resulting in only about 30% of arsenic impurities being removed by the traditional pickling method; (2) The mechanism of multi-metal synergistic pollution is complex. Metals form Fe-P intermetallic compounds during the gas-liquid-solid three-phase migration process, and the d-p orbital hybridization between transition metals and phosphorus severely restricts their application in semiconductors; (3) The entrainment effect of organic solvents is prominent. Organic pollutants crack to produce phosphorus carbide in high-temperature processes, leading to lattice defects.

[0007] To address the above scientific problems, the present invention uses microchannel process intensification oxidation, extraction technology, and distillation-adsorption deep impurity removal technology to remove main impurities such as arsenic, metals, and organic substances, meeting the purity requirements of electronic-grade phosphoric acid for chips. It has incomparable advantages over traditional batch production methods, providing an important way for the improvement of industrial continuous production, realizing the continuous, safe, efficient, and stable production of this product. In addition, the product purity and quality have also been significantly improved. Summary of the Invention

[0008] The purpose of the present invention is to overcome the defects of the prior art, adopt a method of synergistic action of chemical and physical methods, and introduce a microchannel reactor with higher safety, enabling the invention to deeply remove various impurities and achieve the purpose of improving the purity of refined yellow phosphorus.

[0009] A method for purifying electronic-grade yellow phosphorus using a multi-stage series microreactor-distillation-adsorption system is carried out according to the following steps:

[0010] (1) At room temperature, industrial yellow phosphorus containing various impurities such as arsenic, metal compounds, and organic substances is melted and mixed with high-purity water in a certain proportion, and continuously stirred to make material A. Hydrogen peroxide and the oxidation enhancer potassium dichromate are mixed in a certain proportion and continuously stirred and mixed evenly to make material B. The two materials are respectively fed into the microreactor through metering pumps for mixing and reaction. The mixing temperature is controlled by an external heat exchanger, and the heat transfer medium is heat-conducting oil;

[0011] (2) The reaction product is fully mixed with the organic solvent chloroform through a microchannel mixer. The mixed product flows out from the reactor outlet. Then, the organic phase in the product collection area is separated and washed with water to obtain refined yellow phosphorus, which then enters the distillation column;

[0012] (3) After purging the distillation column with nitrogen, add yellow phosphorus that has been intensively oxidized with hydrogen peroxide and purified by extraction into the distillation column. After heating, pump the bottom material of the column to the falling film evaporator through a circulation pump, and conduct the top condenser water circulation and bottom heating. After the temperature stabilizes, start refluxing. The gaseous yellow phosphorus taken out comes into full contact with the adsorbent in the adsorption column, and impurities are further removed. After condensation, it enters the product collector, which is the required product. Through content analysis, the removal rate of arsenic impurities in industrial yellow phosphorus impurities reaches 99.9952%, the removal rate of metal impurities is 99.11%, the removal rate of organic impurities is 99.9995%, the yield of yellow phosphorus is 76.03%, and the purity of yellow phosphorus is 99.9999913% (i.e., 7N grade).

[0013] In step (1), the temperature of the microchannel reactor is 45°C to 65°C, preferably 55°C; the concentration of hydrogen peroxide is 22% to 28%, preferably 26%; the material ratio of hydrogen peroxide to yellow phosphorus is (2 - 5):1, preferably 4:1; potassium dichromate is added to hydrogen peroxide in a volume ratio of 1500:1 with yellow phosphorus and mixed thoroughly. High-purity water and yellow phosphorus are heated to 45°C and mixed in a liquid-solid ratio of 1:5.

[0014] In step (2), the extraction agents involved include halogenated hydrocarbons (such as chloroform, carbon tetrachloride, chloroethane, chlorobenzene, etc.), alcohols (such as isoamyl alcohol, sec-octanol, isobutanol, etc.), esters (such as ethyl acetate, amyl acetate, butyl acetate, etc.), etc.

[0015] In step (2), the reaction product and the organic solvent chloroform are mixed in a volume ratio of 1:3 in the microchannel, and the standing outflow material separates the organic solvent from yellow phosphorus. The separated yellow phosphorus is washed 3 times with water and 1 time with alkali.

[0016] In step (3), the number of trays in the distillation column is 50 to 90, preferably 90; the number of feed trays is 20 to 35, preferably 34; the reflux ratio is (10 - 6):1, preferably 8:1; the specific surface area of the activated carbon is 8000m 2 / g to 12000m 2 / g, preferably 1000m 2 / g; the vacuum degree is 11 kPa.

[0017] All the above purification processes are carried out in a multi-stage series microreactor, distillation column, and adsorption column. The reaction system includes different functional areas such as a feed zone, preheating zone, reaction zone, extraction zone, water washing zone, distillation zone, adsorption zone, and discharge zone. Among them, the preheating zone, reaction zone, and extraction zone are all arranged by n series-connected microchannel reactor modules, and the module arrangement method is in series.

[0018] The microreactor channel structure adopted by the microchannel reactor module includes a chain type, an enhanced hybrid circular cake type rectangular flat pipe structure, a heart shape structure, a fish shape, a direct current shape, and a circular cake type pulse variable diameter type rectangular flat pipe structure.

[0019] The present invention has the following main characteristics compared with the prior art:

[0020] 1. The present invention adopts a hydrogen peroxide enhanced oxidation method-chloroform extraction microchannel reaction process, which solves the problems of easy decomposition of hydrogen peroxide at high temperature, fast oxidation heat release, and high explosion risk. The reaction time is short, shortened from several hours in the traditional process to several minutes, significantly improving the purification efficiency.

[0021] 2. Aiming at the difficulty of removing metal and organic impurities in industrial grade yellow phosphorus with hydrogen peroxide to meet the requirements of electronic grade yellow phosphorus, rectification and adsorption methods are used to further remove impurities from the oxidized and refined yellow phosphorus. The operation is simple, the cost is low, and the safety is high. While greatly improving the purity of yellow phosphorus, it effectively solves the safety hazards such as spontaneous combustion and explosion in traditional yellow phosphorus production, and is suitable for large-scale industrial production.

[0022] 3. Different structures of microchannel reactors adopted in the present invention can strengthen mass transfer and heat transfer performance, keep the reaction temperature constant, and improve the safety of the reaction process. Description of the Drawings

[0023] Figure 1 is the synthesis process flow chart of yellow phosphorus purification of the present invention;

[0024] Figure 2 is the flow chart of the reactor system used in the present invention; In the figure: 1, 11, 12, 13, 14, 15, 16, 17: feed pumps, 2, 21, 22, 23, 24, 25, 26, 27, 28, 29: pressure gauges, 3, 31, 32, 33, 34, 35, 36, 37, 38: flow meters, 4, 41, 42, 43, 44, 45: temperature gauges, 5, 51, 52: microchannel reactors, 6: water washing tank, 61: alkali washing tank, 7: rectification tower, 71: adsorption tower, 8, 81: condensers, 9: product receiving device.

[0025] Figure 3 is the chain structure adopted in the process of the present invention;

[0026] Figure 4 is the enhanced hybrid circular cake type rectangular flat pipe structure adopted in the process of the present invention;

[0027] Figure 5 is the heart shape structure adopted in the process of the present invention.

[0028] Figure 6 is the fish shape structure adopted in the process of the present invention;

[0029] Figure 7 is the DC structure adopted in the process of the present invention;

[0030] Figure 8 is the circular cake type pulse variable diameter rectangular flat pipe structure adopted in the process of the present invention. Specific embodiments

[0031] The present invention will be described in detail below with reference to the embodiments. However, the following embodiments are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

[0032] Example 1

[0033] A method for purifying electronic-grade yellow phosphorus by a multi-stage series microreactor - rectification - adsorption system, comprising the following steps:

[0034] (1) Device: Refer to Figure 2 Determine a connection mode of a multi-stage series microreactor - rectification - adsorption system. The pipeline type is a heart-shaped structure + circular cake type pulse variable diameter rectangular flat pipe structure. The inner diameter of the pipeline and the liquid holdup are determined according to the flow rate and reaction residence time, and the heat exchange medium is heat-conducting oil.

[0035] (2) At 45 °C, hydrogen peroxide with a mass concentration of 26% and potassium dichromate as an oxidation enhancer are fully mixed, denoted as material A, where the amount of potassium dichromate is added according to a volume ratio of 1:1500 to yellow phosphorus. At the same time, industrial-grade yellow phosphorus with a purity of more than 99.5% and high-purity water are fully mixed at a ratio of 1:5 at 45 °C, denoted as material B. Adjust the flow pumps of materials A and B according to the mass ratio of hydrogen peroxide:yellow phosphorus of 4:1, and introduce them into the microchannel reactor. React fully at 45 °C. Then introduce it into the microchannel mixer, and mix it with the organic solvent chloroform at a volume ratio of 1:3 to extract organic impurities. Separate the organic solvent and water through 3 times of water washing and 1 time of alkali washing. First, purge the rectification column with nitrogen to create an inert environment, and then use a vacuum pump to evacuate the rectification system to a vacuum, with a vacuum degree of 11 kPa. Refined yellow phosphorus is added to the rectification column. The total number of trays in the rectification column is 90, and the feeding position is at the 34th tray. The yellow phosphorus vapor is condensed by the top condenser of the column and refluxed into the column at a reflux ratio of 8:1. The yellow phosphorus liquid refluxed from the top of the column and the yellow phosphorus vapor rising from the bottom of the column are in full contact in the column for vapor-liquid exchange. The gas phase passes through the activated carbon in the adsorption column with a specific surface area of 1200 m 2 / g to obtain high-purity yellow phosphorus. After content analysis, the purity of yellow phosphorus is 99.999842%, and the yield is 90.54%.

[0036] Example 2

[0037] A method for purifying electronic-grade yellow phosphorus by a multi-stage series microreactor-distillation-adsorption system, comprising the following steps:

[0038] (1) Equipment: Refer to Figure 2 Determine the connection mode of a multi-stage series microreactor-distillation-adsorption system. The pipeline type is enhanced hybrid circular cake type rectangular flat pipeline structure + chain type. The inner diameter of the pipeline and the holdup are determined according to the flow rate and the reaction residence time. The heat exchange medium is heat-conducting oil.

[0039] (2) At 45 °C, 28% hydrogen peroxide by mass and potassium dichromate as an oxidation enhancer are fully mixed and denoted as material A, where the amount of potassium dichromate is added according to a volume ratio of 1:1500 to yellow phosphorus. At the same time, above 99.5% industrial-grade yellow phosphorus and high-purity water are fully mixed at a ratio of 1:5 at 45 °C and denoted as material B. Adjust the flow pumps of materials A and B according to the mass ratio of hydrogen peroxide:yellow phosphorus of 4:1, and introduce them into the microchannel reactor. React fully at 55 °C. Then introduce it into the microchannel mixer and mix it with the organic solvent chloroform at a volume ratio of 1:3 to extract organic impurities. Separate the organic solvent and water by washing with water three times and washing with alkali once. First, purge the distillation column with nitrogen to create an inert environment, and then use a vacuum pump to evacuate the distillation system to a vacuum with a vacuum degree of 11 kPa. Refined yellow phosphorus is added to the distillation column. The total number of trays in the distillation column is 90, and the feeding position is at the 34th tray. The yellow phosphorus vapor is condensed by the top condenser and refluxed into the column at a reflux ratio of 8:1. The yellow phosphorus liquid refluxed from the top of the column and the yellow phosphorus vapor rising from the bottom of the column are in full contact in the column for vapor-liquid exchange. The gas phase passes through the activated carbon in the adsorption column with a specific surface area of 1000 m 2 / g to obtain high-purity yellow phosphorus. After content analysis, the purity of yellow phosphorus is 99.999989% and the yield is 90.96%.

[0040] Example 3

[0041] A method for purifying electronic-grade yellow phosphorus by a multi-stage series microreactor-distillation-adsorption system, comprising the following steps:

[0042] (1) Equipment: Refer to Figure 2 Determine the connection mode of a multi-stage series microreactor-distillation-adsorption system. The pipeline type is enhanced hybrid circular cake type rectangular flat pipeline structure + circular cake type pulse variable diameter type rectangular flat pipeline structure. The inner diameter of the pipeline and the holdup are determined according to the flow rate and the reaction residence time. The heat exchange medium is heat-conducting oil.

[0043] (2) At 45 °C, hydrogen peroxide with a mass concentration of 26% is fully mixed with potassium dichromate as an oxidation enhancer, denoted as material A, where the amount of potassium dichromate is added according to a volume ratio of 1:1500 to yellow phosphorus. Meanwhile, at 45 °C, industrial-grade yellow phosphorus with a purity of over 99.5% and high-purity water are fully mixed at a ratio of 1:5, denoted as material B. Adjust the flow pumps of material A and material B according to the mass ratio of hydrogen peroxide to yellow phosphorus of 5:1, and introduce them into a microchannel reactor. React fully at 45 °C. Then introduce them into a microchannel mixer and mix fully with chloroform as an organic solvent at a volume ratio of 1:3 to extract organic impurities. Separate the organic solvent and water through 3 times of water washing and 1 time of alkali washing. First, purge the distillation column with nitrogen to create an inert environment, and then use a vacuum pump to evacuate the distillation system to a vacuum, with a vacuum degree of 11 kPa. Add refined yellow phosphorus into the distillation column. The total number of trays in the distillation column is 90, and the feeding position is at the 34th tray. The yellow phosphorus vapor is condensed by the condenser at the top of the column and refluxed into the column according to a reflux ratio of 8:1. The yellow phosphorus liquid refluxed at the top of the column and the yellow phosphorus vapor rising from the bottom of the column are in full contact in the column for vapor-liquid exchange. The gas phase passes through an adsorption column with activated carbon having a specific surface area of 800 m 2 / g to obtain high-purity yellow phosphorus. Through content analysis, the purity of yellow phosphorus is 99.99997% and the yield is 91.22%.

[0044] Example 4

[0045] A method for purifying electronic-grade yellow phosphorus by a multi-stage series microreactor-distillation-adsorption system, comprising the following steps:

[0046] (1) Device: Refer to Figure 2 Determine the connection mode of a multi-stage series microreactor-distillation-adsorption system. The pipeline type is an enhanced mixed circular cake type rectangular flat pipeline structure + straight-through type. The inner diameter of the pipeline and the holdup are determined according to the flow rate and the reaction residence time. The heat exchange medium is heat-conducting oil.

[0047] (2) At 45 °C, hydrogen peroxide with a mass concentration of 26% is fully mixed with potassium dichromate as an oxidation enhancer, denoted as material A, where the amount of potassium dichromate is added according to a volume ratio of 1:1500 to yellow phosphorus. Meanwhile, at 45 °C, industrial-grade yellow phosphorus with a purity above 99.5% and high-purity water are fully mixed at a ratio of 1:5, denoted as material B. Adjust the flow pumps of materials A and B according to the mass ratio of hydrogen peroxide to yellow phosphorus of 3:1, and introduce them into a microchannel reactor. React fully at 55 °C. Then introduce it into a microchannel mixer and mix it fully with the organic solvent chloroform at a volume ratio of 1:3 to extract organic impurities. Separate the organic solvent and water through 3 times of water washing and 1 time of alkali washing. First, purge the distillation column with nitrogen to create an inert environment, and then use a vacuum pump to evacuate the distillation system to a vacuum with a vacuum degree of 11 kPa. Refined yellow phosphorus is added to the distillation column. The total number of trays in the distillation column is 90, and the feeding position is at the 34th tray. The yellow phosphorus vapor is condensed by the condenser at the top of the column and refluxed into the column according to a reflux ratio of 8:1. The yellow phosphorus liquid refluxed at the top of the column and the yellow phosphorus vapor rising from the bottom of the column are in full contact in the column for vapor-liquid exchange. The gas phase passes through an adsorption column with activated carbon having a specific surface area of 1000 m 2 / g to obtain high-purity yellow phosphorus. Through content analysis, the purity of yellow phosphorus is 99.99999576%, and the yield is 89.88%.

[0048] Example 5

[0049] A method for purifying electronic-grade yellow phosphorus by a multi-stage series microreactor-distillation-adsorption system, comprising the following steps:

[0050] (1) Device: Refer to Figure 2 Determine the connection mode of a multi-stage series microreactor-distillation-adsorption system. The pipeline type is straight-through + straight-through. The inner diameter of the pipeline and the holdup are determined according to the flow rate and the reaction residence time. The heat exchange medium is heat-conducting oil.

[0051] (2) At 45 °C, hydrogen peroxide with a mass concentration of 22% is fully mixed with potassium dichromate as an oxidation enhancer, denoted as material A, where the amount of potassium dichromate is added according to a volume ratio of 1:1500 to yellow phosphorus. Meanwhile, at 45 °C, industrial-grade yellow phosphorus with a purity of over 99.5% is fully mixed with high-purity water at a ratio of 1:5, denoted as material B. Adjust the flow pumps of material A and material B according to the mass ratio of hydrogen peroxide to yellow phosphorus of 4:1, and introduce them into a microchannel reactor. React fully at 55 °C. Then introduce it into a microchannel mixer and mix it fully with the organic solvent chloroform at a volume ratio of 1:3 to extract organic impurities. Separate the organic solvent and water through 3 times of water washing and 1 time of alkali washing. First, purge the distillation column with nitrogen to create an inert environment, and then use a vacuum pump to evacuate the distillation system to a vacuum with a vacuum degree of 11 kPa. Refined yellow phosphorus is added to the distillation column. The total number of trays in the distillation column is 90, and the feeding position is at the 34th tray. The yellow phosphorus vapor is condensed by the top condenser and refluxed into the column at a reflux ratio of 10:1. The yellow phosphorus liquid refluxed from the top of the column and the yellow phosphorus vapor rising from the bottom of the column come into full contact in the column for vapor-liquid exchange. The gas phase passes through an adsorption column with activated carbon having a specific surface area of 1000 m 2 / g to obtain high-purity yellow phosphorus. Through content analysis, the purity of yellow phosphorus is 99.9999902% and the yield is 89.31%.

[0052] Example 6

[0053] A method for purifying electronic-grade yellow phosphorus by a multi-stage series microreactor-distillation-adsorption system, comprising the following steps:

[0054] (1) Device: Refer to Figure 2 Determine the connection mode of a multi-stage series microreactor-distillation-adsorption system. The pipeline type is a circular cake type pulse variable diameter rectangular flat pipeline structure + chain type. The inner diameter of the pipeline and the holdup are determined according to the flow rate and reaction residence time. The heat transfer medium is heat-conducting oil.

[0055] (2) At 45 °C, hydrogen peroxide with a mass concentration of 26% is fully mixed with potassium dichromate as an oxidation enhancer, denoted as material A, where the amount of potassium dichromate is added according to a volume ratio of 1:1500 to yellow phosphorus. At the same time, industrial-grade yellow phosphorus with a purity of over 99.5% and high-purity water are fully mixed at a ratio of 1:5 at 45 °C, denoted as material B. Adjust the flow pumps of material A and material B according to the mass ratio of hydrogen peroxide to yellow phosphorus of 4:1, and introduce them into a microchannel reactor. React fully at 55 °C. Then introduce it into a microchannel mixer and mix it fully with the organic solvent chlorobenzene at a volume ratio of 1:3 to extract organic impurities. Separate the organic solvent and water through 3 times of water washing and 1 time of alkali washing. First, purge the distillation column with nitrogen to create an inert environment, and then use a vacuum pump to evacuate the distillation system to a vacuum with a vacuum degree of 11 kPa. Refined yellow phosphorus is added to the distillation column. The total number of trays in the distillation column is 90, and the feeding position is at the 34th tray. The yellow phosphorus vapor is condensed by the top condenser and refluxed into the column according to a reflux ratio of 6:1. The yellow phosphorus liquid refluxed from the top of the column and the yellow phosphorus vapor rising from the bottom of the column come into full contact in the column for vapor-liquid exchange. The gas phase passes through an adsorption column with activated carbon having a specific surface area of 1200 m 2 / g to obtain high-purity yellow phosphorus. Through content analysis, the purity of yellow phosphorus is 99.999988% and the yield is 91.18%.

[0056] Example 7

[0057] A method for purifying electronic-grade yellow phosphorus using a multi-stage series microreactor-distillation-adsorption system, comprising the following steps:

[0058] (1) Device: Refer to Figure 2 Determine the connection mode of a multi-stage series microreactor-distillation-adsorption system. The pipeline type is a circular cake type pulse variable diameter rectangular flat pipeline structure + fish shape. The inner diameter of the pipeline and the holdup are determined according to the flow rate and reaction residence time. The heat transfer medium is heat-conducting oil.

[0059] (2) At 45 °C, hydrogen peroxide with a mass concentration of 26% is fully mixed with potassium dichromate as an oxidation enhancer, denoted as material A, where the amount of potassium dichromate is added according to a volume ratio of 1:1500 to white phosphorus. At the same time, industrial-grade white phosphorus with a purity of over 99.5% and high-purity water are fully mixed at a ratio of 1:5 at 45 °C, denoted as material B. Adjust the flow pumps of material A and material B according to the mass ratio of hydrogen peroxide to white phosphorus of 4:1, and introduce them into a microchannel reactor. React fully at 60 °C. Then introduce them into a microchannel mixer and mix fully with butyl acetate as an organic solvent at a volume ratio of 1:3 to extract organic impurities. Separate the organic solvent and water through 3 times of water washing and 1 time of alkali washing. First, purge the distillation column with nitrogen to create an inert environment, and then use a vacuum pump to evacuate the distillation system to a vacuum with a vacuum degree of 11 kPa. Add refined white phosphorus into the distillation column. The total number of trays in the distillation column is 90, and the feeding position is at the 34th tray. The white phosphorus vapor is condensed by the condenser at the top of the column and refluxed into the column according to a reflux ratio of 6:1. The white phosphorus liquid refluxed at the top of the column and the white phosphorus vapor rising from the bottom of the column are in full contact in the column for vapor-liquid exchange. The gas phase passes through an adsorption column with activated carbon having a specific surface area of 1000 m 2 / g to obtain high-purity white phosphorus. Through content analysis, the purity of white phosphorus is 99.999979% and the yield is 90.01%.

[0060] Example 8

[0061] A method for purifying electronic-grade white phosphorus by a multi-stage series microreactor-distillation-adsorption system, comprising the following steps:

[0062] (1) Device: Refer to Figure 2 Determine the connection mode of a multi-stage series microreactor-distillation-adsorption system. The pipeline type is an enhanced mixed circular cake type rectangular flat pipeline structure + fish shape. The inner diameter of the pipeline and the holdup are determined according to the flow rate and the reaction residence time. The heat transfer medium is heat-conducting oil.

[0063] (2) At 45 °C, hydrogen peroxide with a mass concentration of 28% is fully mixed with potassium dichromate as an oxidation enhancer, denoted as material A, where the amount of potassium dichromate is added according to a volume ratio of 1:1500 to yellow phosphorus. Meanwhile, at 45 °C, industrial-grade yellow phosphorus with a purity above 99.5% and high-purity water are fully mixed at a ratio of 1:5, denoted as material B. Adjust the flow pumps of materials A and B according to the mass ratio of hydrogen peroxide to yellow phosphorus of 4:1, and introduce them into a microchannel reactor. React fully at 45 °C. Then introduce them into a microchannel mixer and mix fully with the organic solvent n-butanol at a volume ratio of 1:3 to extract organic impurities. Separate the organic solvent and water through 3 times of water washing and 1 time of alkali washing. First, purge the distillation column with nitrogen to create an inert environment, and then use a vacuum pump to evacuate the distillation system to a vacuum with a vacuum degree of 11 kPa. Add refined yellow phosphorus to the distillation column. The total number of trays in the distillation column is 90, and the feed position is at the 34th tray. The yellow phosphorus vapor is condensed by the top condenser of the column and refluxed into the column according to a reflux ratio of 8:1. The yellow phosphorus liquid refluxed from the top of the column and the yellow phosphorus vapor rising from the bottom of the column come into full contact in the column for vapor-liquid exchange. The gas phase passes through an adsorption column with activated carbon having a specific surface area of 1000 m 2 / g to obtain high-purity yellow phosphorus. Through content analysis, the purity of yellow phosphorus is 99.999875% and the yield is 90.87%.

[0064] Example 9

[0065] A method for purifying electronic-grade yellow phosphorus using a multi-stage series microreactor-distillation-adsorption system, comprising the following steps:

[0066] (1) Equipment: Refer to Figure 2 Determine the connection mode of a multi-stage series microreactor-distillation-adsorption system. The pipeline type is chain + heart-shaped. The inner diameter of the pipeline and the holdup are determined according to the flow rate and the reaction residence time. The heat exchange medium is heat-conducting oil.

[0067] (2) At 45 °C, hydrogen peroxide with a mass concentration of 26% is fully mixed with potassium dichromate as an oxidation enhancer, denoted as material A, where the amount of potassium dichromate is added according to a volume ratio of 1:1500 to yellow phosphorus. At the same time, industrial-grade yellow phosphorus with a purity of over 99.5% and high-purity water are fully mixed at a ratio of 1:5 at 45 °C, denoted as material B. The flow pumps of materials A and B are adjusted according to the mass ratio of hydrogen peroxide to yellow phosphorus of 4:1 and fed into a microchannel reactor, and they react fully at 55 °C. Then it is fed into a microchannel mixer and fully mixed with the organic solvent chloroform at a volume ratio of 1:3 to extract organic impurities, and the organic solvent and water are separated by 3 times of water washing and 1 time of alkali washing. First, nitrogen is used to purge the distillation column to create an inert environment, and then the distillation system is evacuated to a vacuum of 11 kPa with a vacuum pump. The refined yellow phosphorus is added to the distillation column. The total number of trays in the distillation column is 90, and the feeding position is at the 34th tray. The yellow phosphorus vapor is condensed by the condenser at the top of the column and refluxed into the column at a reflux ratio of 8:1. The yellow phosphorus liquid refluxed at the top of the column and the yellow phosphorus vapor rising from the bottom of the column come into full contact in the column for vapor-liquid exchange. The gas phase passes through an adsorption column with activated carbon having a specific surface area of 1000 m 2 / g to obtain high-purity yellow phosphorus. Through content analysis, the purity of yellow phosphorus is 99.9999913% and the yield is 91.41%.

Claims

1. A method for purifying electronic-grade yellow phosphorus by a multi-stage series microreactor-rectification-adsorption system, characterized in that The following steps are carried out: (1) At room temperature, industrial yellow phosphorus containing various impurities such as arsenic, metal compounds, and organic substances is melted and then mixed with high-purity water in a certain proportion, and continuously stirred to make material A. Hydrogen peroxide and potassium dichromate as an oxidation enhancer are mixed in a certain proportion and continuously stirred and mixed evenly to make material B. The two materials are respectively fed into a micro-reactor through metering pumps for mixing and reaction. The mixing temperature is controlled by an external heat exchanger, and the heat exchange medium is heat-conducting oil; (2) The reaction product is fully mixed with the organic solvent chloroform through a micro-channel mixer. The mixed product flows out from the reactor outlet. Then, the organic phase in the product collection area is separated and washed with water to obtain refined yellow phosphorus, which then enters the distillation column; (3) After purging the distillation column with nitrogen, yellow phosphorus after being strengthened and oxidized by hydrogen peroxide and extracted and purified is added into the distillation column. After heating, the bottom material of the column is transported from the circulation pump to the falling-film evaporator, and the top condensate water circulation and bottom heating are carried out. After the temperature is stable, reflux starts. The gaseous yellow phosphorus taken out is in full contact with the adsorbent in the adsorption column, and impurities are further removed. After condensation, it enters the product collector, which is the required product.

2. The method for purifying electronic-grade yellow phosphorus by using a multi-stage series microreactor-rectification-adsorption system according to claim 1, characterized in that Among them, in step (1), the temperature of the micro-channel reactor is 45°C to 65°C, preferably 55°C; the concentration of hydrogen peroxide is 22% to 28%, preferably 26%; the material ratio of hydrogen peroxide to yellow phosphorus is (2 to 5):1, preferably 4:1; among them, potassium dichromate is added to hydrogen peroxide according to the volume ratio of 1500:1 with yellow phosphorus, and high-purity water and yellow phosphorus are heated to 45°C and fully mixed according to the liquid-solid ratio of 1:

5.

3. The method for purifying electronic-grade yellow phosphorus by using a multi-stage series microreactor-rectification-adsorption system according to claim 1, wherein Among them, the extraction agents involved in step (2) include halogenated hydrocarbons (such as chloroform, carbon tetrachloride, chloroethane, chlorobenzene, etc.), alcohols (such as isoamyl alcohol, sec-octanol, isobutanol, etc.), esters (such as ethyl acetate, amyl acetate, butyl acetate, etc.).

4. The method for purifying electronic-grade yellow phosphorus by using a multi-stage series micro-reactor - distillation - adsorption system according to claim 1, wherein Among them, in step (2), the reaction product and the organic solvent chloroform are mixed in a micro-channel according to the volume ratio of 1:3, and the standing outflow material separates the organic solvent from yellow phosphorus. The separated yellow phosphorus is washed 3 times with water and 1 time with alkali.

5. The method for purifying electronic-grade yellow phosphorus by using a multi-stage series microreactor-rectification-adsorption system according to claim 1, characterized in that Among them, in step (3), the number of distillation column trays is 50 to 90, preferably 90; the number of feed trays is 20 to 35, preferably 34; the reflux ratio is (10 to 6):1, preferably 8:1; the specific surface area of the activated carbon is 8000 m 2 / g to 12000 m 2 / g, preferably 1000 m 2 / g; the vacuum degree is 11 kPa.

6. The method for purifying electronic-grade yellow phosphorus by using a multi-stage series microreactor-rectification-adsorption system according to claim 1, characterized in that All the above purification processes are carried out in a multi-stage series micro-reactor, distillation column, and adsorption column. The reaction system includes different functional areas such as a feeding area, a preheating area, a reaction area, an extraction area, a water washing area, a distillation area, an adsorption area, and a discharging area. Among them, the preheating area, reaction area, and extraction area are all composed of n series-connected micro-channel reactor modules arranged in series, and the module arrangement method is series connection.

7. A method for purifying electronic-grade yellow phosphorus by using a multi-stage series microreactor-rectification-adsorption system according to claim 1, characterized in that The micro-reactor channel structure adopted by the micro-channel reactor module includes a chain type, an enhanced hybrid circular cake type rectangular flat pipe structure, a heart shape, a fish shape, a straight flow type, and a circular cake type pulse variable diameter type rectangular flat pipe structure.

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