Geoscience Reference
In-Depth Information
Figure 5.17 Negative solubility for berlinite in
6.1 M H
3
PO
4
[76]
.
T
(
°
C)
245
225
205
185
165
145
0
1.0
2.0
3.0
AIPO
4
(moles)
Figure 5.18 Solubility of AlPO
4
(in wt%) as a function of
temperature
[83]
.
10
8
6
4
2
100
200
300
400
Temperature (
°
C)
authors have also carried out thermodynamic interpretation of the solubility data.
The dissolution of berlinite in the mixtures of acids H
2
SO
4
and HCl is a process of
complex formation between Al
3
1
and the ligands present in the solution: OH
2
,
H
2
O, Cl
2
, HSO
4
;
At low temperature, the complexes are similar to
those of AlPO
4
in HCl; i.e., with Al
SO
4
;
H
2
PO
4
:
Cl complexes predominating. Even polynu-
clear complexes might form a broader metastable zone under these circumstances.
