ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 9, pp. 1464−1471. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © A.Sh. Bikmurzin, A.A. Lamberov, R.G. Romanova, 2015, published in Zhurnal Prikladnoi Khimii, 2015, Vol. 88, No. 9, pp. 1320−1328.
Preparation of Cerium Oxalate from Spent Iron–Potassium
Catalyst for Dehydrogenation of Isoamylenes into Isoprene
A. Sh. Bikmurzin
, A. A. Lamberov
, and R. G. Romanova
Nizhnekamskneftekhim PAO, Nizhnekamsk, Tatarstan, 423574 Russia
Kazan (Volga Region) Federal University, ul. Kremlevskaya 18, Kazan, Tatarstan, 420008 Russia
Kazan National Research Technological University, ul. Karla Marksa 72, Kazan, Tatarstan, 420015 Russia
Received October 5, 2015
Abstract—The cerium recovery in the oxalate form from spent iron–potassium catalyst for dehydrogenation of
isoamylenes into isoprene was studied. The optimum conditions allowing preparation of the pure product with
high degree of recovery were found. It was proved by X-ray diffraction, thermal gravimetric analysis, differential
scanning calorimetry, and X-ray ﬂ uorescence analysis that the product obtained by the precipitation was cerium
oxalate decahydrate containing no less than 98 wt % main substance.
The reprocessing and recycling of components of
spent catalysts is an urgent problem for both resource
saving and preservation of natural ecosystems.
One of the problems of the modern petrochemical
industry is associated with spent iron–potassium
catalysts used for dehydrogenation of isoamylenes and
ethylbenzene in production of isoprene and styrene,
respectively. From 300 to 360 t of such spent catalysts
is annually formed only at PAO Nizhnekamskneftekhim
[1–4]. These catalysts are systems based on iron
oxides, containing cerium and molybdenum oxides as
promoters; the cerium content is from 8 to 15 wt %.
Disposal of the spent catalysts requires considerable
expenditures because of the need for ensuring special
conditions for the utilization of wastes containing toxic
elements: molybdenum and cerium. Because of high
cost of cerium compounds, it seems appropriate to
recover them from the spent catalysts and return into the
production process. The starting cerium compound for
producing iron–potassium catalysts is cerium oxalate
This study was aimed at developing a procedure for
cerium recovery in the form of oxalate from spent iron–
potassium catalyst for dehydrogenation of isoamylenes.
The following tasks were set to accomplish this goal:
to study the catalyst dissolution process, to choose the
solvent and optimum conditions for transferring the
spent catalyst into the solution, to examine the inﬂ uence
of various chemical and process parameters on the
recovery selectivity and on the yield of cerium in the
form of oxalate from the solution of the spent catalyst,
and to determine the composition and purity of the
cerium oxalate prepared by the developed procedure.
The investigation objects were spent iron–potassium
catalysts for dehydrogenation of isoamylenes into
isoprene. Prior to trials, the catalysts were ﬁ nely
crushed, and the fraction with the particle size no larger
than 0.2 mm was taken. Experiments were performed
with the spent catalyst containing (wt %) 9.36 K
, 1.96 СаО, 2.01 MgO, 1.83 МоО
, and Fe
the remainder .
The solubility of the samples was studied using the
procedure described below. A ﬂ at-bottomed conical
ﬂ ask equipped with a reﬂ ux condenser was charged
with the preset volume of the solvent (25–500 mL),
and the contents were heated with stirring to 85–90°С.
After this temperature was reached, a ~5-g sample of
the spent catalyst, weighed on an analytical balance