Geoscience Reference
In-Depth Information
H
2
O
LiTaO
3
LiTaO
3
Li
3
TaO
4
LiTaO
3
+ Ta
2
O
5
Li
3
TaO
4
10
9
8
7
6
5
4
3
2
1
Li
3
TaO
4
LiTaO
3
Ta
2
O
5
LiOH
Figure 4.5 The phase diagram of crystallization in the system LiO
2
a
Ta
2
O
5
a
H
2
O at 750
C
and 1700 atm.
4.3 Solutions, Solubility, and Kinetics of Crystallization
This is one of the most important aspects of the hydrothermal growth of crystals.
Initial failures in the hydrothermal growth of a specific compound are usually the
result of lack of proper data on the type of solvents,
the solubility, and sol-
vent
solute interaction. Despite the large amount of literature data already available,
it is still a highly attractive field in hydrothermal research, geoscience, and so on. For
example, geologists are now in a position to tell us much about the conditions of for-
mation of hydrothermal ore deposits (e.g., temperature, pressure, oxidation potential,
pH, and fluid salinity), but in order to fully understand the mechanisms of transport
and deposition of ore minerals, information about metal complex formation, stability,
and stoichiometry in high-temperature and high-pressure aqueous electrolyte solu-
tions, thermodynamic properties of electrolytes at high pressures and high tempera-
tures, phase behavior, transport phenomena, and electrical and optical properties is
necessary
[13
15]
. Unfortunately, most of the studies have been performed only at
the saturated vapor pressure of the system and very few combined high-temperature
and high-pressure experiments have been designed to yield thermodynamic data.
Recent advances in computer technology, which have seen both speed and stor-
age capacities dramatically increased, offer the possibility that chemical speciation
modeling of multicomponent electrolyte solutions can be made much more reliable
