Development of Hydrothermal Hot-Pressing Apparatus Available in Supercritical Region

Takashi Ishiyama*, Tsunetaka Banba*, Hisayoshi Mitamura* and Toshikatsu Maeda*
* Department of Environmental Sciences, Japan Atomic Energy Research Institute
+ Correspondence should be addressed to Tsunetaka Banba:
(2-4 Shirane, Shirakata, Tokai-mura, Ibaraki 319-1195, Japan)

Abstract
A hydrothermal hot-pressing apparatus equipped with special carbon packings was developed for use in a supercritical region. The apparatus was applied to hydrothermal solidification of simulated incineration fly ash at 500*C[Celsius degeree] and 64 MPa. In the products formed after hydrothermal hot-pressing under these conditions, considerable amounts of three new crystalline phases were formed although no new crystalline phase was found in a product after conventional hydrothermal hot-pressing at 250*C[Celsius degeree] and 64 MPa.

Key words: supercritical region, hydrothermal hot-pressing apparatus, carbon packing, incineration fly ash, and solidification