Geoscience Reference
In-Depth Information
Figure 5.61 Pa
Ca
pH diagrams of
the Ca
P
H
2
O system at 25
C for
a
Ca
5
1.67a
P
[228]
.
1.5
Ca
2+
1.5
1.5
Ca
2
P
2
O
7
Ca
5
(PO
4
)
3
OH
0
-2
Ca
3
(PO
4
)
2
202468 0 2 4 6
pH
Figure 5.62 Pa
Ca
pH diagrams of
the Ca
P
H
2
O system at 300
C
for a
Ca
5
1.67a
P
[228]
.
1.5
10
CaOH
+
Ca
2+
Ca (OH)
2
(s)
5
Ca
2
P
2
O
7
Ca
5
(PO
4
)
3
OH
0
Ca
3
(PO
4
)
2
-2
-2
0
2
4
6
8
10
12
14
16
pH
Figure 5.63 Free energy of reaction
against temperature for some calcium
phosphates according to Eqs (1)
(5)
for water vapor fugacity equal to
0.03 atm, except for the dashed line,
Eq. (3), which corresponds to water
vapor fugacity equal to 1.0 atm
[228]
.
10,000
“Eq. (3)”
“Eq. (3)”o
8000
“Eq. (1)”
6000
4000
2000
0
-2000
“Eq. (5)”
-4000
“Eq. (2)”
-6000
“Eq. (4)”
-8000
-10,000
0
200 400
800
1200
1600
T
(K)
