Canada - Memorial University of Newfoundland

identical Na/PO. mole ratio as that ofthe solid maricite (i.e. I: 1) at 200°C. These runs
were unsuccessful in producing maricite, the reaction vessel contained unreacted starting
materials.
2.4,3 Syntheses of Sodium Iron Hydroxy Phosphate ("SIHP")
2.4.3.1 Iron Nitriloacetate (FeIllNTA) Experiments
Quinlan (1996) obtained SIHP by three different synthetic routes. Samples of
SIHP were produced by reacting (i) iron phosphatc and aqueous sodium phosphate
(Na/PO. = 2.15), (il) magnetite and aqueous sodium phosphate (NalP04 = 2.15), and (iii)
hematite and aqueous sodium phosphate (NalP04 = 2.5), all at 250°C for three weeks.
Quinlan also attempted to synthesis SIHP by thermally decomposing the FelllNTA
complcx in the presence ofan oxidizing agent, to create a more suitable environment for
synthesizing thc iron(lll) reaction product. Both CuD and NaNOJ were used as possible
oxidizing agents for the reaction but the experiments were unsuccessful in producing
SIHP.
In principle, SlHP could be synthesised according to the following reaction with
FelliNTA as the iron source:
3 FellINTA(aq) + 13 Na\aq) + 6 HPO/-(aq) + 10 OH"(aq)
----lo 3 Na.Felll(OH)(PO.h·l/3NaOH(s) + 6 H20(I)
+ decomposition products ofHNTA2'(aq)
51
(2.4)