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THE EXPERIMENTAL STUDY OF NEODYMIUM SPECIATION IN WATER VAPOUR

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

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  1. THE EXPERIMENTAL STUDY OF NEODYMIUM SPECIATION IN WATER VAPOUR Nail R. Zagrtdenov, Andrew Y. Bychkov, Irina Y. Nikolaeva Lomonosov Moscow State University

  2. Influence of ligands • Influence of fluid components such as water, chlorine or fluorine can increase the amount of matter which can be transported by gas. This effect has been noticed for such low-volatile elements as gallium, silver, gold, copper etc. (Pokrovski et al., 2013) • Migdisov and Williams-Jones, 2013

  3. Natural evidences of the transportation of the REE 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.

  4. Natural evidences of the transportation of the REE 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.

  5. Scheme of experiments in autoclaves 1 – before the experiment, 2 – during the experiment

  6. Identification of the Nd speciation in the gaseous phase by static method in autoclaves Nd(OH)3(solid) = Nd(OH)3(gas) Blue marks– at 200 °C, red marks – at 250 °C

  7. 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.

  8. The dynamic flow method experiment scheme 1 – graduated cylinder, where water displaces the air for gaining the air flow, 2 –thermostat, 3 – furnace with quartz tube, 4 – sample receptacle

  9. Identification of the Nd speciation in the gaseous phase by flow method

  10. 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.

  11. Comparison of flow system (black marks) and autoclaves (red marks) data

  12. Surface springs sampling

  13. Nd in vapor and liquid in thermal springs Nd(OH)3(aq)=Nd(OH)3(gas) 350oC 300oC

  14. Conclusions • 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). • The results of the flow method experiments have showed that the solubility of Nd2O3 increases with water fugacity. The proposed reaction is the following: 0,5 Nd2O3 (solid) + 1,5 H2O (gas) = Nd(OH)3 (gas).

  15. Conclusions • Our experimental data can explain the natural observation. The fact that concentrations in thermal vapor are higher then thermodynamic calculation can be explained by presence of other species or absence of equilibrium between liquid and vapor.

  16. Thank you for your attention!

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