Original scientific paper

Spontaneous Precipitation in the System Uranyl(2+ )nitrate Potassium Hydroxide - Phosphoric Acid - Water

N. Pavković ; Department of Physical Chemistry, Facuity of Sci ence, University of Zagreb, P.O.B. 163, 41001 Zagreb, Croatia, Yugoslavia
M. Marković ; Department of Physical Chemistry, Facuity of Sci ence, University of Zagreb, P.O.B. 163, 41001 Zagreb, Croatia, Yugoslavia
B. Kojić-Prodić ; Department of Physical Chemistry, Facuity of Sci ence, University of Zagreb, P.O.B. 163, 41001 Zagreb, Croatia, Yugoslavia

Abstract

The precipitation system U02(NOs)2-KOH-H3P04-H20 (at
298 K) aged for 1 day and for 30 days is examined ([U02(NOs)2] =
= 1 · 10-a mol dm-3, [KOH] varied from 1 · 10-6 to 6 · 10-1 mol dm-3,
[H3P04] from 2 · 10-4 to 6 · 10-1 mol dm-3 and 1.5 precipitation and phase boundaries are determined.
The solid phases U02HP04 · 4 H20(s) and (U02)s(P04)2 · 8 H20
are stable at [KOH] < 1 · 10-3 mol dm-3, 1.5 precipitate at pH > 9.5. The stability region of KU02P04 · 3 H20(s)
is found at high concentrations of KOH and H3P04. X-ray diffraction
pattern of this compound is given. According to the
precipitation boundary after 30 days (equilibrium conditions) the
solubility product of KU02P04 · 3 H20 is determined: log ([K+] ·
· [U022+] [P043-]) = -- 26.28 (at I =0 mol dm-3).

Keywords

Hrčak ID:

194255

URI

https://hrcak.srce.hr/194255

Publication date:

15.12.1982.

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