Hydro Thermal Method
This method is a potential method for obtaining pure and nano particle size Zirconium Oxide powder, based on Zirconium compounds derived from natural Zircon Sand. Hydro Thermal technique is once again classified into two different types
- Hydro Thermal Crystallization of Amorphous Zirconia
- Hydro Thermal Oxidation of Zircon Metal
Hydro Thermal Crystallization of Amorphous Zirconia
Hydro Thermal Crystallization method involves preparation of amorphous form Zirconia from Zirconium Chloride Solution by precipitation technique. The pure Zirconium Chloride solution is treated with ammonia which initiates the precipitation of Zirconia. The solution is passed through filtering process wherein the precipitate is separated. The separated filtered mass precipitate is dispersed in distilled water and the filtering is repeated. The re-filtering process can be done multiple times to get pure filtered mass.
An aqueous suspension of the obtained amorphous material is autoclaved at 100 MPA pressure and at a temperature of 200oC to 600oC in presence of a mineraliser. The pressure vessel is quenched in cold water. There are different types of mineralisers used in industry for this purpose, which includes potassium hydroxide, sodium hydroxide, lithium chloride and potassium chromide. The particle size of Zirconium Oxide vary with the type of mineraliser used and the process temperature adopted. The entire structural re-arrangement of Zirconium Oxide is accelerated by the presence of the mineraliser.
To be Contd…..
