ZrONO3)2-H3PO4-KF(HF)-H2O system at molar ratios of PO 4 3-/Zr=0.5-1.6 as the basis for phase formation

The system ZrO(NO3)(2)-H3PO4-KF(HF)-H2O was studied at similar to 20A degrees C along sections at molar ratios of PO (4) (3-) = 0.5, 1.0, and 1.6; KF: Zr = 1-5; and HF: Zr = 2-6. Phases in precipitates were identified by X-ray powder diffraction; IR spectroscopy; and crystal-optical, chemical, X-ray fluorescence and thermal analyses. The following crystalline phases were isolated: potassium fluorozirconates K3ZrF7, K2ZrF6, delta-KZrF5, and KZrF5 center dot H2O; zirconium hydrophosphate Zr(HPO4)(2) center dot 0.5H(2)O; and potassium fluorophosphate zirconate K3Zr3F3(HPO4)(3)(PO4)(2). The following amorphous basic oxo(hydroxo)fluorohydrophosphate nitrates were isolated: K4Zr4O2.5F8(HPO4)(2)(NO3)(3) center dot 6H(2)O, K2Zr3O3F2(HPO4)(2)(NO3)(2) center dot H2O, and KZr3O1.5F3(HPO4)(2)(NO3)(3) center dot 2H(2)O. Fields of solid phases were constructed, and the roles of anions and cations in the phase formation were considered.