THE EXPERIMENTAL STUDY OF NEODYMIUM SPECIATION IN WATER VAPOUR. Nail R. Zagrtdenov , Andrew Y. Bychkov , Irina Y. Nikolaeva Lomonosov Moscow State University. Influence of ligands.
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THE EXPERIMENTAL STUDY OF NEODYMIUM SPECIATION IN WATER VAPOUR
Nail R. Zagrtdenov, Andrew Y. Bychkov, Irina Y. Nikolaeva
Lomonosov Moscow State University
Gilbert C.D., Williams-Jones A.E.(2008) sampled and analyzed REE-enriched fumarolic encrustations derived from the active degassing fumaroles of OldoinyoLengai volcano, Tanzania, which, according to the authors, precipitated from volcanic gases.
Möller P.et al.(2003)measured concentrations of REE and Y in condensates of Larderello-Travale geothermal field, the abundance of REE ranges from 0.1 to about 10 pmol/kg.
1 – before the experiment, 2 – during the experiment
Nd(OH)3(solid) = Nd(OH)3(gas)
Blue marks– at 200 °C, red marks – at 250 °C
The results of experiments in autoclaves have demonstrated that the solubility of Nd(OH)3 in water vapour doesn’t depend on water fugacity and the proposed reaction is as follows:
Nd(OH)3 (solid) = Nd(OH)3 (gas)
pK =9.15±0.42 at 200 °C,
9.30±0.31 at 250 °C.
1 – graduated cylinder, where water displaces the air for gaining the air flow, 2 –thermostat, 3 – furnace with quartz tube, 4 – sample receptacle
The results of the flow method experiments have showed that the solubility increases with water fugacity rising with increasing temperature. The reaction is the following (according to the slope of 1.5):
0,5 Nd2O3 (solid) + 1,5 H2O (gas) = Nd(OH)3 (gas)
pK = 8.31±0.42 at 300 °C,
7.74±0.31 at 350 °C,
7.03±0.61 at 450 °C.
Surface springs sampling
0,5 Nd2O3 (solid) + 1,5 H2O (gas) = Nd(OH)3 (gas).