Rare Earth Elements in Mineral Deposits: Speciation in Hydrothermal Fluids and Partitioning in Calcite
Table 3
Starting conditions for the different model types. Parameters that were varied include temperature, pressure, salinity and XCO2; REE concentrations were fixed at 100 ppm.
Model type
T
Calcite
REE
NaCl
XCO2
HCl
(°C)
(bar)
(g)
(ppm)
(wt.%)
(m)
(m)
Speciation (Ia) NaCl-CO2-poor system
150
2
1.27
100
0.5
0.01
0.1
0.003–1.05
350
2
2.30
100
0.5
0.01
0.1
0.003–1.05
Speciation (Ib) CO2-rich NaCl-poor system
150
1000
0.5
1.34
100
0.5
0.1
0.1
0.05–12.53
350
1000
0.5
1.65
100
0.5
0.1
0.1
0.05–12.53
Speciation (Ic) CO2-NaCl-rich system
150
1000
0.5
1.35
100
20
0.1
0.1
0.05–12.53
350
1000
0.5
2.27
100
20
0.1
0.1
0.05–12.53
Fluid-calcite partitioning (IIa)
25–400
1000
5–10
4.87
100
0.5
0.1
-
-
25–400
1000
5–10
4.82
100
5
0.1
-
-
25–400
1000
5–10
4.76
100
20
0.1
-
-
Fluid-calcite partitioning (IIb)
25–400
1000
50
4.76
100
0.5
0.1
-
-
25–400
1000
50
4.76
100
20
0.1
-
-
is water vapor saturation pressure. (150°C): 4.76; (200°C): 15.54; (350°C): 165.21. nitial pH values before adding NaOH. mounts of NaOH added until pH values reach 10.
