ISSN 1070-4272, Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 3, pp. 265−269. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © I.V. Babichev, A.A. Il’in, R.N. Rumyantsev, N.E. Nikonorova, A.P. Il’in, 2014, published in Zhurnal Prikladnoi Khimii, 2014, Vol. 87,
No. 3, pp. 298−302.
INORGANIC SYNTHESIS AND INDUSTRIAL
Currently a problem of recycling of spent catalysts
becomes increasingly urgent, since this type of waste is
prohibited for burial in the ground and their storage in
areas of chemical manufactures contributes to worsen-
ing environmental conditions . Spent catalysts can be
a source of valuable and expensive components.
The iron–molybdenum catalysts used in the produc-
tion of formaldehyde contain about 55% of molybdenum
[2, 3]. These catalysts have a relatively short lifespan, not
exceeding 2 years. The main cause of their deactivation is
destruction of granules and a partial removal of the active
component from the catalyst surface [4, 5]. In this regard,
the question arises about their recovery or processing to
extract expensive molybdenum oxide.
For transition of molybdenum in a solution various
reagents can be used that is associated with the ability of
molybdenum trioxide to dissolve in acidic and alkaline
There exists published information on the
extraction of molybdenum oxide from spent molybde-
num-containing catalysts for hydrotreating of petroleum
fractions. For example, authors of  studied kinetics of
the extraction of molybdenum trioxide by a solution of
hydrochloric acid depending on the acid concentration
and temperature. In  a method for leaching MoO
a sodium carbonate solution was proposed in order to
optimize the extraction process. A study in  was de-
voted to examination of an inﬂ uence of temperature, time
of the process, and a height of a layer in the processing
by sublimation of deactivated catalysts on the basis of
molybdenum and cobalt oxides used in the hydrotreating
of petroleum for sulfur removing. The authors discussed
the difﬁ culties encountered during the processing of such
man-made waste and proposed ways to resolve them.
The aim of the study consists in examination of MoO
dissolution in ammonia solutions, determination of dis-
tinct stages and mechanism of dissolution of the catalyst
to optimize methods of extracting molybdenum trioxide.
The experiments were conducted with spent catalyst
for the partial oxidation of methanol to formaldehyde of
a grade F, which represents pellets of cylindrical shape
and greenish-gray color. For analysis a weighted portion
(10 g) of the spent catalyst was taken. Thus, a content of
molybdenum in terms of MoO
was 8.49 g. The catalyst
pellets were crushed in a mortar to powder state of pellet
size of 0.25–0.5 mm and dissolved for a preset time in
an ammonia solution of a 2.5–25% concentration.
Therewith the reaction of free molybdenum oxide with
ammonia solution occurs:
OH = (NH
Recovery of MoO
from Spent Catalysts of Partial Oxidation
of Methanol to Formaldehyde
I. V. Babichev, A. A. Il’in, R. N. Rumyantsev, N. E. Nikonorova, and A. P. Il’in
Research Institute of the Thermodynamics and Kinetics of Chemical Processes,
Ivanovo State University of Chemical Technology, Sheremet’evskii pr. 7, Ivanovo, 153000 Russia
Received March 28, 2014
Abstract—An effect of an ammonia solution concentration, temperature, l : s ratio on a MoO
was revealed in studying ammonia leaching of molybdenum oxide from spent iron-molybdenum catalyst of
oxidation of methanol to formaldehyde The data obtained allow to optimize the extraction process of MoO
the spent Fe–Mo catalysts.