Continuous hydrothermal synthesis of inorganic nanopowders in supercritical water: Towards a better control of the process

Abstract

A hydrothermal synthesis process working in supercritical conditions ( T > 374 °C, P > 22 MPa) and in a continuous mode has been developed for inorganic nanopowder synthesis. This paper presents a review of the past 5 years of research conducted on this process. Numerous materials (oxides: ZrO 2, TiO 2, Fe 2O 3…, ferrites: Fe 2CoO 4…, or BaZrO 3) were obtained with specific features. Some technical issues have been solved, that are presented here. Heat transfer was studied, leading to a more efficient design of the reactor. Future developments have been examined through process engineering, in which our group is engaged, especially through CFD modelling.