Drying of zirconia ceramic powder - Supercritical fluid drying

The previous article introduced the direct high-temperature calcination method and freeze-drying method for zirconia ceramic powder, each of which has its own advantages. Below, Kezhong Ceramic Factory will continue to introduce the supercritical fluid drying method to everyone.

Supercritical Fluid Drying (SCFD) refers to a fluid whose pressure and temperature are higher than the critical pressure and temperature, respectively. It has many important and unique properties, such as its density being similar to that of a liquid but its viscosity being similar to that of a gas, and its diffusion coefficient being about 100 times higher than that of a liquid. In the supercritical state, there is no gas-liquid interface, and surface tension and capillary forces are also eliminated, Moreover, due to its ability to significantly dissolve volatile substances, its solubility varies with changes in temperature and pressure.

Zirconia ceramic plate

Therefore, if the operating conditions are properly controlled, the liquid in the gel can be removed without affecting the framework of the gel, and agglomeration will not occur. Supercritical fluid drying technology is a new technology and method for preparing nanomaterials. The prepared powder has good thermal stability, and has the characteristics of good collection, large sample size, high solvent recovery rate, and pure sample.

However, because supercritical fluid drying is generally carried out under high pressure, and the system involved is also complex, industrial scale-up process process and phase equilibrium research are required to ensure the optimization of industrial scale production. Although this drying method is costly, the resulting zirconia ceramic powder is relatively pure, and there are almost no pores on the surface of some processed ceramic rods.

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