Spherical alumina produced by the high-temperature melt spraying method has the characteristics of high sphericity and high content of α-phase alumina. It shows superior performance when used as a filler for rubber, plastics and ceramic raw materials.
Ultrafine spherical alumina has excellent characteristics such as corrosion resistance, high temperature resistance, high hardness, high strength, wear resistance, oxidation resistance, good insulation and large surface area. It is widely used in metallurgy, chemical industry, electronics, national defense, aerospace and nuclear industries, etc. High-tech field. At present, the annual growth rate of the demand for ultra-fine spherical alumina in the domestic and foreign markets is increasing. Therefore, it is of great significance to further explore new methods for preparing ultrafine spherical alumina powder.
The essence of the spray method for preparing spherical alumina is to realize the phase transition in a relatively short period of time. The surface tension is used to make the product spherical. According to the characteristics of the phase transition, it can be divided into spray pyrolysis, spray drying and spray melting. Law.
1. Spray pyrolysis
The spray pyrolysis method uses Al(SO4)3, Al(NO3)3 and AlCl3 solutions as raw materials to form spherical droplets through atomization, and then form spherical alumina powder through high-temperature pyrolysis. The pyrolysis process of this method requires 900°C and consumes a lot of energy.
2. Spray drying method
The spray drying method firstly reacts aluminum salt solution with ammonia water to prepare alumina sol, and then spray-drying the alumina sol at 150-240°C to prepare spherical alumina powder.
Compared with the spray pyrolysis method, this method has the advantage of reducing energy consumption.
3. Jet melting method
Jet melting method uses plasma flame to directly melt solid aluminum powder or aluminum oxide powder, and then immediately do annealing treatment. The degree of spheroidization can be controlled by adjusting the composition of the carrier gas and the power of the DC arc, and a hollow structure can be prepared.
Luoyang Trunnano Tech Co., Ltd (TRUNNANO) is a professional spherical alumina supplier with over 12 years experience in chemical products research and development. We accept payment via Credit Card, T/T, West Union and Paypal. Trunnano will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.
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