Geoscience Reference
In-Depth Information
Figure 10.94 Flexural
strength per manufacturing
energy (MPa, m
3
/GJ) for the
hydrothermally solidified
waste soil (earth ceramics) and
other common ceramic
products
[418]
.
1.3
Ceramic tile
1.5
Sanitary ware
1.0
Autoclaved aerated
concrete
2.6
Hydrothermally solidified
waste soil
(Earth ceramics)
2 1 0
Flexural strength per manufacturing
energy (MPa, m
3
/GJ)
10.10 Future Trends in Hydrothermal Research
Hydrothermal technology, whether it is hydrothermal or solvothermal or supercriti-
cal, has a great perspective owing to its multifaceted advantages in processing of a
wide variety of advanced materials starting from bulk single crystals to fine and
ultrafine crystals and finally the nanocrystals or nanoparticles. The hydrothermal
technology has been revived significantly in the last few years for the growth of
most strategic crystals like ZnO, GaPO
4
, langasite, and GaN, as bulk single crys-
tals, followed by the synthesis of diamond, silicon carbide, silicon nitride, ruby,
emerald, zoisite, etc. The processing of fine particles and nanoparticles is growing
fast as a most attractive tool owing to several advantages in comparison with the
conventional methodologies. More recently the concept of multienergy hydrother-
mal technology has been introduced and it is going to play a vital role in future
materials processing because of its speed, cost, and convenience and environmen-
tally benign conditions. Here, it is very important to note the role played by the
chemistry, especially the precursor's preparation for materials processing whether
it is hydrothermal or other conventional methods. For industrial scale production of
materials, the supercritical hydrothermal, particularly the supercritical CO
2
and
H
2
O will have a greater role to play for a wide range of materials, as they are part
of the green chemistry. Also the wasteless processing is the future of materials pro-
cessing with an eye on the environmentally benign conditions without leading to
the global warming. In this context, the soft solution processing, which embraces
