Preparation method of nanoscale high-purity controllable crystal phase lead oxide
A method for preparing nanoscale high-purity β-PbO by high-temperature reaction and rapid cooling in a reaction tube has solved the environmental protection and purity problems of existing lead oxide preparation methods, and realized the industrial production of nanoscale high-purity β-PbO in a highly efficient and environmentally friendly manner.
Patent Information
- Application Number
- CN202511340750.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-18
- Publication Date
- 2025-11-18
AI Technical Summary
Existing methods for preparing lead oxide suffer from problems such as high environmental pressure, high production costs, low product purity, high energy consumption, and difficulty in large-scale production.
Nanoscale high-purity β-PbO was prepared by reacting nanoscale 5N lead powder with oxygen-containing gas at high temperature in a reaction tube and then rapidly cooling it at the tail end. The crystal phase morphology was controlled, an inert gas was used as the carrier gas, the cooling rate was controlled at 40~60℃/min, and a ceramic filter was used to capture the product.
We have achieved efficient and environmentally friendly preparation of nanoscale high-purity β-PbO. The product has high purity and is suitable for large-scale industrial production, meeting the needs of high-end electronic materials and optical devices.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of lead oxide preparation, in particular to a preparation method of nanoscale high-purity controllable crystal phase lead oxide. BACKGROUND
[0002] Lead oxide (β-PbO) is an inorganic compound, which is a yellow orthorhombic crystal with a density of 9.64 g / cm 3 Its close lattice arrangement and high bond energy make it difficult to undergo phase transition or decomposition at room temperature. β-PbO will reverse to α-PbO above 475~583℃, and is not easy to be oxidized in air at room temperature, but will be partially converted into lead trioxide when heated to 300~450℃. Grinding or mechanical pressure may induce the formation of α-PbO, but β-PbO has higher stability under static conditions.
[0003] High-purity nanoscale lead oxide (β-PbO) suitable for precision industry generally refers to the sum of non-lead impurities (such as Sn, Bi, Cd, Fe, Cu, Mg, Ni, etc.) being less than 10 ppm. In high-end industrial electronic materials, it is often used to manufacture conductive adhesive, glass powder and photoelectric conversion devices. In the preparation of optical devices, it is used as a raw material for high-refractive optical glass. At the same time, it has unique advantages in precision components such as detection instruments and thermal analysis sample cups in the semiconductor field. Due to its specific electrical and semiconductor properties, it has received widespread attention. In certain high-tech fields such as lead-acid battery production in the new energy battery field, precision optical lenses and optical fiber communication equipment production, only nanoscale high-purity can meet these performance standards. Research and development of high-purity lead oxide synthesis method not only can open up its application field, enhance market competitiveness, but also meet the development trend of lead oxide application industry at this stage, promote scientific research development, and has important significance for promoting the progress of material science and realizing the innovation of material application.
[0004] At present, the preparation methods of lead oxide mainly include lead nitrate thermal decomposition method, lead carbonate decomposition method and high-position lead compound reduction method. The lead nitrate thermal decomposition method produces a large amount of toxic gas, which puts great pressure on environmental protection and has high production cost; the lead carbonate decomposition method is easy to generate high-valence lead compounds, and the product purity is not high; the high-position lead reduction method has large energy consumption, long production time and is not suitable for large-scale production. The common high-temperature oxidation method of metallic lead (>600℃ molten lead + blast) has high energy consumption, lead vapor pollution, high operation risk and is easy to generate other by-products, and the crystal morphology is inconsistent. SUMMARY
[0005] The present application provides a preparation method of nanoscale high-purity controllable crystal phase lead oxide, which is used for efficiently preparing nanoscale high-purity β-PbO with controllable crystal form, and meets the preparation needs of industry.
[0006] In view of the above, the scheme of the present application is: The present application provides a preparation method of nanoscale high-purity controllable crystal phase lead oxide, comprising the following steps: a) obtaining or preparing nanoscale 5N lead powder; b) spraying the nanoscale lead powder into a reaction tube with continuous oxygen-containing gas, and reacting at 450-650℃ for 0.05-0.1h; c) after the reaction product is rapidly cooled and cooled by the cooler connected to the tail of the reaction tube, the pure β-PbO nanometer powder is obtained by capturing.
[0007] Further, the oxygen-containing gas is oxygen or air.
[0008] Further, the flow rate of the oxygen-containing gas is 0.05-3L / min.
[0009] Further, the flow rate of the nanoscale 5N lead powder during the spraying process is 5-10g / min.
[0010] Further, inert gas is used as the carrier gas during the spraying process of the nanoscale 5N lead powder.
[0011] Further, the cooling speed during the rapid cooling process is 40-60℃ / min to below 100℃.
[0012] Further, the preparation process of the nanoscale 5N lead powder is as follows: the 5N lead block is cooled in liquid nitrogen at-20--40℃ for 1-2h, pre-crushed, and then subjected to multi-stage ball milling in a liquid nitrogen planetary ball mill to obtain nanoscale 5N lead powder.
[0013] Preferably, the ball-to-material ratio (5-15):1 during the planetary ball milling process is 200-400rpm, and the temperature is maintained at-40--60℃.
[0014] Further, a powder injector is used during the spraying process of the nanoscale lead powder; and the material used for the inner cavity of the powder injector or the reaction tube is selected from one of platinum, alumina, zirconia, boron nitride, or quartz.
[0015] Further, a ceramic filter cartridge is used for the capturing process.
[0016] Compared with the prior art, the present application has the following beneficial effects: The preparation method provided by the present application can effectively ensure the purity of the product and control the crystal morphology of β-PbO by blending nanoscale lead powder with oxygen-containing gas in a reaction tube for high-temperature reaction and rapidly cooling at the tail, and the process flow is simple, energy-saving, environmentally friendly, and suitable for large-scale application in industrial production. DETAILED DESCRIPTION
[0017] The technical solution of the present invention will now be clearly and completely described in conjunction with preferred embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] In the following examples, the 5N lead blocks were purchased from Zhongnuo New Materials and were from the same batch. The high-purity oxygen used in the examples was oxygen with a purity ≥ 99.99%.
[0019] Example 1
[0020] 1) Take 1000g of 5N lead block and freeze it in liquid nitrogen at -40℃ for 1 hour. Take out the lead block and put it into a jaw crusher to crush it into small pieces less than 1mm. Then, put the crushed lead block into a liquid nitrogen planetary ball mill for multiple ball milling processes. The ball-to-material ratio is set to 10:1, the rotation speed is 300rpm, and liquid nitrogen is continuously injected to maintain -50℃. This includes fine grinding (0.5-0.1mm) and fine grinding (0.05μm). 2) The ball-milled powder is sieved using an argon-protected centrifugal classifier until it is vibrated to a size ≤0.05μm; 3) The sieved powder is sprayed into the oxidation tube through a powder injector. Nitrogen is used as the pressurized carrier gas at a flow rate of 5 g / min, and the oxidation tube is heated to 450℃. Then, high-purity oxygen is introduced into the tube, and the sprayed aerosol powder is kept at the temperature in the oxidation tube for 0.05 h. The flow rate of high-purity oxygen entering and exiting is controlled at 0.05 L / min. 4) The reaction product is instantly cooled to below 100°C at a rate of 50°C / min by a cooler connected to the end of the oxidation tube to avoid crystal transformation. Pure β-PbO nanopowder is then captured and collected by a ceramic filter element.
[0021] Example 2
[0022] 1) Take 1000g of 5N lead block and freeze it in liquid nitrogen at -30℃ for 1.5h. Take out the lead block and put it into a jaw crusher to crush it into small pieces less than 1mm. Then, put the crushed lead block into a liquid nitrogen planetary ball mill for multiple ball milling processes. The ball-to-material ratio is set to 8:1, the rotation speed is 400rpm, and liquid nitrogen is continuously injected to maintain -50℃. This includes fine grinding (0.5-0.1mm) and fine grinding (0.05μm). 2) The ball-milled powder is sieved using an argon-protected centrifugal classifier until it is vibrated to a size ≤0.05μm; 3) The sieved powder is sprayed into the oxidation tube through a powder injector. Nitrogen is used as the pressurized carrier gas at a flow rate of 10 g / min, and the oxidation tube is heated to 500℃. Then, high-purity oxygen is introduced into the tube, and the sprayed aerosol powder is kept at the oxidation tube temperature for 0.1 h. During the process, the flow rate of high-purity oxygen is controlled at 3 L / min. 4) The reaction product is instantly cooled to below 100°C at a rate of 60°C / min by a cooler connected to the end of the oxidation tube to avoid crystal transformation. Pure β-PbO nanopowder is then captured and collected by a ceramic filter element.
[0023] Example 3
[0024] 1) Take 1000g of 5N lead block and freeze it in liquid nitrogen at -40℃ for 1 hour. Take out the lead block and put it into a jaw crusher to crush it into small pieces less than 1mm. Then, put the crushed lead block into a liquid nitrogen planetary ball mill for multiple ball milling processes. The ball-to-material ratio is set to 12:1, the rotation speed is 300rpm, and liquid nitrogen is continuously injected to maintain -50℃. This includes fine grinding (0.5-0.1mm) and fine grinding (0.05μm). 2) The ball-milled powder is sieved using an argon-protected centrifugal classifier until it is vibrated to a size ≤0.05μm; 3) The sieved powder is sprayed into the oxidation tube through a powder injector. Nitrogen is used as the pressurized carrier gas at a flow rate of 7 g / min, and the oxidation tube is heated to 500℃. Then, high-purity oxygen is introduced into the tube, and the sprayed aerosol powder is kept at the oxidation tube temperature for 0.1 h. During the process, the flow rate of high-purity oxygen is controlled at 2 L / min. 4) The reaction product is instantly cooled to below 100°C at a rate of 50°C / min by a cooler connected to the end of the oxidation tube to avoid crystal transformation. Pure β-PbO nanopowder is then captured and collected by a ceramic filter element.
[0025] Example 4
[0026] 1) Take 1000g of 5N lead block and freeze it in liquid nitrogen at -40℃ for 2 hours. Take out the lead block and put it into a jaw crusher to crush it into small pieces less than 1mm. Then, put the crushed lead block into a liquid nitrogen planetary ball mill for multiple ball milling processes. The ball-to-material ratio is set to 10:1, the rotation speed is 300rpm, and liquid nitrogen is continuously injected to maintain -50℃. This includes fine grinding (0.5-0.1mm) and fine grinding (0.05um). 2) The ball-milled powder is sieved using an argon-protected centrifugal classifier until it is vibrated to a size ≤0.05μm; 3) The sieved powder is sprayed into the oxidation tube through a powder injector. Nitrogen is used as the pressurized carrier gas at a flow rate of 10 g / min, and the oxidation tube is heated to 650℃. Then, high-purity oxygen is introduced into the tube, and the sprayed aerosol powder is kept at the oxidation tube temperature for 0.1 h. During the process, the flow rate of high-purity oxygen is controlled at 3 L / min. 4) The reaction product is instantly cooled to below 100°C at a rate of 50°C / min by a cooler connected to the end of the oxidation tube to avoid crystal transformation. Pure β-PbO nanopowder is then captured and collected by a ceramic filter element.
[0027] Comparative Example 1
[0028] A method for preparing lead oxide, which differs from Example 1 in that the reaction product is cooled to below 100°C at a rate of 10°C / min, while the other steps are the same.
[0029] Comparative Example 2
[0030] A method for preparing lead oxide differs from Example 1 in that the oxidation tube is heated to 300°C for reaction, while the other steps are the same.
[0031] Comparative Example 3
[0032] A method for preparing lead oxide differs from Example 1 in that the oxidation tube is kept at a temperature for 0.5 hours, while the other steps are the same.
[0033] The products prepared in the above examples and / or comparative examples were tested as follows.
[0034] 1) The ICP test results of the final products of Examples 1 to 4 are shown in Table 1.
[0035] Table 1:
[0036] As can be seen from Table 1, the preparation methods of the above embodiments do not significantly change the impurity content, and the products meet the high purity level (non-lead impurity content less than 10 ppm) required for high-end industrial electronic materials applications.
[0037] 2) The test results of the technical indicators of the final products of Examples 1-4 and Comparative Examples 1-3 are shown in Table 2.
[0038] Table 2:
[0039] As can be seen from Table 2, the β-PbO content of the products obtained in Examples 1-4 is greater than 99.5%, and the contents of lead peroxide and metallic lead are less than 0.02% and 0.08%, respectively, all of which meet the requirements of the lead oxide standard. The β-PbO content of the products obtained in Comparative Examples 1-3 is less than 99%, and the contents of lead peroxide and metallic lead are greater than 1.00% and 1.00%, respectively, which do not meet the requirements of the lead oxide standard. This indicates that the present invention can effectively control the crystal form of the product by mixing nano-lead powder with oxygen-containing gas in a reaction tube at high temperature and then rapidly cooling it at the tail end.
[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for preparing nanoscale high-purity controllable crystalline phase lead oxide, characterized in that the steps include... include: a) Obtaining or preparing nanoscale 5N lead powder; b) Spray nano-sized lead powder into a reaction tube continuously supplied with oxygen-containing gas and react at 450~650℃ for 0.05~0.1h; c) After the reaction product is rapidly cooled by a cooler connected to the tail of the reaction tube, pure β-PbO nanopowder is obtained by capture.
2. The preparation method according to claim 1, characterized in that, The oxygen-containing gas is oxygen or air; and / or, the flow rate of the oxygen-containing gas is 0.05~3L / min.
3. The preparation method according to claim 1, characterized in that, The flow rate of the nano-sized 5N lead powder injection process is 5-10 g / min.
4. The preparation method according to claim 1, characterized in that, The process of injecting nano-sized 5N lead powder uses inert gas as the carrier gas.
5. The preparation method according to claim 1, characterized in that, The rapid cooling process cools the temperature to below 100°C at a cooling rate of 40-60°C / min.
6. The preparation method according to claim 1, characterized in that, The preparation process of the nano-grade 5N lead powder is as follows: 5N grade lead blocks are placed in liquid nitrogen at -20~-40℃ and cooled for 1~2 hours. After pre-crushing, they are placed in a liquid nitrogen planetary ball mill for multi-stage ball milling to obtain nano-grade 5N lead powder.
7. The preparation method according to claim 6, characterized in that, The planetary ball mill ball mill process has a ball-to-material ratio of (5-15):1, a rotation speed of 200-400 rpm, and a temperature maintained at -40~-60℃.
8. The preparation method according to claim 1, characterized in that, The nano-level lead powder injection process uses a powder injector; the material used for the inner cavity or reaction tube of the powder injector is selected from platinum, alumina, zirconium oxide, boron nitride or quartz.
9. The preparation method according to claim 1, characterized in that, The capture process uses a ceramic filter cartridge capture device.