Preparation of high-purity beryllium oxide
Beryllium oxide (BeO), also known as beryllia, is an important inorganic non-metallic material, which has high thermal conductivity, dielectric constant, acoustic impedance, corrosion resistance, ultra-high temperature resistance, and excellent radiation absorption performance. It is not only widely used in high-temperature thermal elements, high-frequency communication devices, light-weight and space industry, electro-acoustics and nuclear power industry, but also used as an important material for making cemented carbide and diamond tools.Due to its excellent thermal performance, high-purity beryllium oxide (BeO) is often used for special applications, such as optical components, semiconductor substrates, and microelectronics. To obtain a high-purity product of BeO, a correct and optimized preparation process is necessary.
The traditional method of preparing BeO involves calcining Be2CO3 powder at temperatures of 1000-1550 ˚C in a furnace. However, this method is not suitable for high-purity products due to the presence of impurity carbonates caused by the action of the furnace atmosphere and solid impurities carried with the raw materials.
A main method for the preparation of high-purity BeO is to reduce powder and the calcination of beryllium hydroxide (Be(OH)2). The preparation process includes the reduction of beryllium chloride with hydrogen gas(H2), the evaporative concentration of beryllium hydroxide,the slow crystallization from saturated solutions, and the precipitation of fines materials by adding electrolyte to the solution.The calcination of the beryllium hydroxide is carried out in the closed pump kiln at about 1000°C.
In order to obtain high-purity beryllium oxide, each step of the preparation process must be carefully determined. In order to achieve a high yield of BeO, it is important that the amount of Be2CO3 is sufficient.In addition, the amount of hydrogen used for the reduction should be controlled and the filtration of the mud should be minimized. The concentration of the solution used for slow crystallization should also be controlled, and it is recommended that the thickness of the beryllium hydroxide is between 0.2 and 0.5 μm. Finally, the calcination process must be conducted in a sealed pump kiln to ensure that no impurity is introduced.
In conclusion, the preparation of high-purity beryllium oxide requires careful process control and optimization to obtain a high yield product. The key steps of the preparation process involve a proper amount of Be2CO3 and hydrogen, the minimization of filtration of the mud, and the control of solution concentration and calcination in a sealed pipe kiln. Following these steps carefully can lead to a successful production of high-purity BeO.
