Influence of fluorides on phase relations in the molten systems MI2O-Р2О5 Mn2O3/MIIO, МI – Li, Na, K; MII – Ni, Co

Olga Petrenko, Ruslan Lavrik, Kateryna Terebilenko, Volodymir Trachevsky, Valentyna Galimova

Abstract

Addition of alkaline fluorides to molten phosphates with a composition MI2O-Р2О5-Mn2O3 and MI2O-Р2О5-MIIO (МI – Li, Na, K) gradually changes the solubility of polyvalent metals oxides and shifts the crystallization areas in the corresponding melts. The results obtained are based on solubility curves found for Mn2O3, СоО and NiO in the fluxes of MI2O-Р2О5 -MF and MI2O-Р2О5 -MF (where МI – Li, Na, K) and X-Ray diffraction, IR spectroscopy and thermal analysis. The presence of 10 and 20 % mass of fluorides provides molten polyphosphates depolymerization and yields pyro- Li2MnP2O7, K2CoP2O7, Na2CoP2O7and orthophosphates Na2Mn3(P2O7)2, NaMnPO4, NaNiPO4 single crystals growth.

Keywords

double phosphates; solubility curves; phosphate; fluoride; flux synthesis

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References

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