S. Khorfan, STUDY OF THE STABILITY OF OCTYL PYROPHOSPHORIC ACID (OPPA) SOLVENT INTHE EXTRACTION OF URANIUM FROM PHOSPHORIC-ACID, Chemical engineering and processing, 32(5), 1993, pp. 273-276
Octyl pyrophosphoric acid (OPPA) solvent is used for the extraction of
uranium from wet phosphoric acid both in pilot and commercial plants.
It is widely known that the extraction factor K of OPPA is much highe
r than for other competing solvents such as octyl phenyl phosphoric ac
id (OPAP) or diethylhexyl phosphoric acid/trioctyl phosphine oxide (DE
HPA/TOPO). However, this solvent is unstable due to the weak bond P-O-
P which hydrolyses readily under the influence of time, temperature an
d contact with acids. The present study investigates the influence of
time, temperature, storage time and contact with different acids on th
e strength of OPPA and has established that the stability decreases wi
th an increase in temperature, storage time and contact with acids.