ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 1, pp. 1−12. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © E.P. Lokshin, O.A. Tareeva, I.R. Elizarova, V.T. Kalinnikov, 2015, published in Zhurnal Prikladnoi Khimii, 2015, Vol. 88, No. 1, pp. 3−14.
INORGANIC SYNTHESIS AND INDUSTRIAL
Recovery of Rare Earth Elements
from the Wet Process Phosphoric Acid
E. P. Lokshin, O. A. Tareeva, I. R. Elizarova, and V. T. Kalinnikov
Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials,
Kola Science Center, Russian Academy of Sciences, Apatity, Akademgorodok 26a, Apatity, 184209 Russia
Received December 29, 2014
Abstract—The methods of producing non-radioactive rare earth concentrate from wet process phosphoric acid
of dihydrate process of Khibiny apatite concentrate sulfuric acid treatment for fertilizer production have been
proven. The features of their use in existing production were characterized.
Total REE oxides (ΣTr
) of loparite concentrate,
which is sole processed raw material source of REEs in
Russia, are virtually no needed for nuclear power plants
using gadolinium, dysprosium, erbium .
Wet process phosphoric acid of dihydrate process
(WPPA) produced form Khibiny apatite concentrate (AC)
is promising source of the REE.
In plants of Russia 2470–2660 and 4275–4750 t of
total REE oxides (ΣTr
) enter production and back
WPPA, respectively. An important advantage of WPPA
is the high content of REE of average and yttrium groups
(Table 1) with a reduced content of lanthanum the most
difﬁ cult to implement. Therefore, development of the
technology of recovery of REE from WPPA is an urgent
task, solution of which has not been found previously .
The purpose of research is to develop methods of
recovery of REE, which are compatible with the current
production of WPPA. The purpose deﬁ nes, in particular,
the need for their performance at elevated temperatures
(75–80°C). Therewith the behavior of natural radionu-
clides was investigated, especially, of thorium, content of
which relative to ΣTr
in WPPA is higher than 1 wt %.
Cation concentration was determined by mass
spectrometry (a mass spectrometer ELAN 9000 DRC-e,
Perkin-Elmer, USA), that of ﬂ uorine, by a potentiometric
method, and that of phosphorus, by photocolorimetry
methods. Solid samples were previously dissolved in
nitric acid. X-ray diffraction (XRD) of precipitations was
carried out on DRON-2.
Recovery of REE from WPPA
by Deposition of Fluor
Solubility of REE ﬂ
uorides and major cationic
impurities in the phosphoric acid solutions at 80°C. To
investigate patterns of deposition of REE and major cat-
ionic impurities from the WPPA into the ﬂ uorophosphate
concentrate a solubility of their ﬂ uorides was examined in
hot (80°C) solutions containing 38 wt % of H
tion 1). Since WPPA contains SO
, in some experiments
2 wt % H
(solution 2) was additionally introduced in
the phosphate solution. For research LaF
(all the ﬂ uorides of reagent
(especially pure grade) and MgF
grade), which were derived from magnesium carbonate
by treatment with HF, were used. To the solutions heated
to 80°C an excess of ﬂ uoride of the element under study
was added, the pulp was maintained at a predetermined
temperature in sealed containers for 14–21 days with oc-
casional stirring. It has been shown that this is sufﬁ cient
time to achieve equilibrium. After keeping the solution
was ﬁ ltered under vacuum, the liquid phase was analyzed.