Table 3

Reactions used to model the precipitation of low temperature iron and silica oxyhydroxides in the system Fe–Si–O–H shown in Fig. 7

Fe (OH)3 (fresh ferric hydroxide) (s) + 2H+ =

Fe2+ + 5/2 H2O + 1/4O2

Fe3(OH)8 (fresh ferrosic hydroxide) + 6H+ =

3Fe2+ + 7H2O + 1/2O2

3Fe(OH)3 (fresh ferric hydroxide) =

Fe3(OH)8 (fresh ferrosic hydroxide) + 1/2H2O + 1/4O2

Fe3(OH)8 (fresh ferrosic hydroxide) =

3Fe(OH)2 (fresh ferrous hydroxide) + H2O + 1/2O2

Fe(OH)2 (fresh ferrous hydroxide) + 2H+ = Fe2+ + 2H2O

SiO2 (amorphous) + 2H2O = Si(OH)4

FeSiO3 (ferrosilite) + 3H2O = Fe(OH)2 (fresh ferrous hydroxide) +

Si (OH)4

FeSiO3 (ferrosilite) + 10H2O + 1/2O2 =

Fe3(OH)8 (fresh ferrosic hydroxide) + 3Si(OH)4

FeSiO3 (ferrosilite) + H2O + 2H+ = Fe2+ + Si(OH)4


Boyd and Scott Geochemical Transactions 2001 2:45   doi:10.1186/1467-4866-2-45

Open Data