Zirconia (ZrO2) is an important inorganic non-metallic material with excellent physical and chemical properties, such as high temperature stability, corrosion resistance, high hardness and high refractive index. Therefore, zirconia has a wide range of applications in the field of raw materials for chemical production, such as ceramics, catalysts, sensors, and biomaterials. In this paper, we will introduce the manufacturing method of zirconia.
I. Raw material preparation
The first step in manufacturing zirconia is to prepare the raw material. Zircon (ZrSiO4) is usually used as the raw material because it is rich in zirconium. Zircon is first crushed and ground into powder, and then chemically treated to remove the impurities.
II. Chemical Synthesis
1. Alkali fusion method
Alkali fusion method is a commonly used method for manufacturing zirconium oxide. In this method, zirconia is mixed with sodium hydroxide or potassium hydroxide and subjected to a fusion reaction at high temperature. The zirconium silicates in the zircon are broken down by alkali to produce sodium or potassium zirconate and a silicate slag. The zirconate is then dissolved with water to give a solution of sodium or potassium zirconate, and zirconium oxide is precipitated by the addition of acid.
2. Sol-gel method
The sol-gel method is a method of generating zirconia by chemical reaction in solution. In this method, a solution of zirconium salts is mixed with a hydrolyzing agent (e.g., ammonia or acetic acid) so that the zirconium salts undergo a hydrolysis reaction to produce a zirconium sol. The sol is then converted into a gel by steps such as heating, drying and roasting, and finally zirconium oxide powder is obtained.
III. Physical processing
1. Ball milling method
Ball milling method is a method of preparing zirconia by chemical action of mechanical force. In this method, zirconia coarse powder is put into the ball mill together with grinding balls, and through long time grinding and impact, the particle size of zirconia powder is reduced and its specific surface area is increased.
2. Vapor Phase Deposition
Vapor phase deposition is a method of preparing zirconia thin films by gas phase reaction. In this method, a gas containing elemental zirconium is introduced into a reaction chamber using techniques such as metal-organic chemical vapor deposition (MOCVD) or physical vapor deposition (PVD), and a zirconia thin film is formed on the substrate by reaction deposition.
IV. Post-treatment
After manufacturing zirconia, post-treatment is often required to improve its properties and meet the needs of different applications. For example, high-temperature sintering can be performed to improve the density and mechanical properties of zirconia; surface coating can be performed to improve its corrosion resistance or biocompatibility; or doping can be performed to adjust its electrical or optical properties.
In conclusion, zirconia can be manufactured in a variety of ways, which can be selected according to different raw materials and process conditions. Different manufacturing methods will have an important impact on the performance of zirconium oxide, so in actual production you need to choose the appropriate manufacturing method according to the specific needs.
