ABSTRACT SUBMMITTED TO IRON CONTROL 2016
SPECIATION OF IRON(III) IN H2O-SO4-Cl SYSTEMS USING THE HYDROGEOCHEMICAL
CODE PHREEQC
Nathalie Jamett, Pía Hernández and María Elisa Taboada
Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta, Avda. Angamos
601,
Antofagasta,
Chile,
nathalie.jamettguillier@csiro.au,
pia.hernandez@csiro.au
and
mariaelisa.taboada@uantof.cl
Jesús M Casas
Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Diagonal las Torres 2640, Peñalolén, Santiago,
Chile, Postal Code 7941169, jesus.casas@uai.cl
ABSTRACT
This work presents the speciation of ferric iron, sulphate and chloride generated by the dissolution of
chemical reagents ferric sulphate and ferric chloride in water at 25, 40 and 60 oC. Experiments were
programed with a thermo-regulated system up to reach equilibrium conditions of solution pH, the solution
samples were analysed by concentration and density. Results shown an important decrease of pH as a
function of dissolved iron, indicating that both iron minerals correspond to strong electrolytes and react
readily within the water. These results have been modelled using the hydrogeochemical code Phreeqc in
order to obtaining the aqueous iron speciation for both reagents. Main speciation results are discussed with
activity comparisons for dissolved iron, sulphate, bisulphate and chloride as a function of pH, salinity and
temperature.
Figure 1 – Iron dissolution vs pH for ferric iron chloride at 25 oC
[Fe(III)], (g/L)
50
45
40
35
30
25
20
15
10
5
0
1.00
1.25
1.50
1.75
2.00
pH
Figure 2 – Iron dissolution vs pH for ferric iron sulphate at 25 oC
KEYWORDS
Ferric Iron Speciation, Chlorine, Sulphate, hydrogeochemical Modelling, Phreeqc.