Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 4, pp. 537−544.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
E.P. Lokshin, V.I. Ivanenko, O.A. Tareeva, R.I. Korneikov, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 4,
INORGANIC SYNTHESIS AND INDUSTRIAL
Sorption Extraction of Lanthanides from Phosphoric Acid
E. P. Lokshin, V. I. Ivanenko, O. A. Tareeva, and R. I. Korneikov
Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Resources,
Kola Scientiﬁ c Center, Russian Academy of Sciences, Apatity, Murmansk oblast, Russia
Received June 30, 2008
Abstract— The possibility of sorption extraction of lanthanides from nitric-phosphoric and phosphoric acid
solutions with inorganic sorbents based on hydrated titanyl hydrophosphate was studied. New technological
solutions were suggested for lanthanide sorption from the products which are formed in processing of the
Khibiny apatite concentrate on mineral fertilizers (frozen nitric-phosphoric acid extract, a product of nitric acid
decomposition of apatite, and the production phosphoric acid from the dihydrate process).
A number of technological schemes is used in acid
decomposition of the Khibiny apatite concentrate (here-
inafter, apatite concentrate).
In the nitric acid method of decomposition, all
lanthanides are transferred from the apatite concen-
trate into a nitric-phosphoric acid solution, potassium
nitrate is crystallized from this solution by freezing to
obtain a frozen nitric-phosphoric acid extract (FNPE),
and sodium carbonate is introduced in a 110% excess
above sodium ﬂ uorosilicate stoichiometry to cause it
Сompleteness of the lanthanide precipitation and
their content in the concentrate depend on the degree
of neutralization of the ﬁ rst proton of orthophosphoric
acid. At high degree of the neutralization the lanthanide
precipitation is virtually complete, but a large number
of phosphates of other elements (mainly, of calcium) is
coprecipitated from the solution, which markedly de-
creases the lanthanide concentration in the concentrate
and yields precipitates in form of a hardly ﬁ lterable
Under the optimal conditions of the neutralization,
the concentrates are enriched in lanthanides, whereas
the most valuable lanthanides of the apatite concentrates
(yttrium, heavy lanthanides) are precipitated to a consid-
erably lesser extent than cerium-group lanthanides. Sub-
sequent dephosphorization of the lanthanide concentrate
In the dihydrate process of sulfuric acid decomposi-
tion of the apatite concentrate, as high as 20% of initial
lanthanides pass into the wet-process phosphoric acid
(WPPA) . As a result, WPPA contains 0.1−0.12 wt %
of the sum of lanthanides in terms of oxides (ΣLn
, from 35 to 75% of yttrium of the apatite concentrate
(according to different reports), 18.0−30.0 of europium,
20.0−22.6 of samarium, only 6.3−8.5 of lanthanum and
11.3−14.5 of cerium [4, 5]. The high content of the most
valuable lanthanides in WPPA makes it interesting object
for the lanthanide extraction.
Neutralization of WPPA, used in production of am-
monium phosphates, with ammonium may cause precipi-
tation of lanthanide phosphate concentrates containing
(wt %): ΣLn
CaO 10.3−10.5, F 4.3−4.6, P
46.4−46.7, and SO
3.0−3.5m thereby the precipitation of lanthanide phos-
phates ceases after a pH 3 of the solution is attained .
This method reaches a reasonably complete precipitation
of all lanthanides and aluminum .
Processing of the lanthanide phosphate concentrates
of complex composition to remove a very low content of
the net component is economically unreasonable.
The production WPPA from the dihydrate process is
supersaturated with lanthanides, ﬁ rst of all, with cerium
. This suggested methods of the lanthanide crystal-
lization on ﬂ uoride or phosphate seed grains in a heated
WPPA ﬂ ow [8, 9].