Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 10, pp. 1874−1876.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
E.N. Volkova, A.I. Demidov, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 10, pp. 1734−1736.
Production of Nickel Sulfate Single Crystals
in Processing of Nickel Oxide Electrodes
of Alkaline Batteries
E. N. Volkova and A. I. Demidov
St. Petersburg State Polytechnic University, St. Petersburg, Russia
Received June 18, 2010
] single crystals were grown by slow cooling and evaporation of a solution for sulfuric
acid leaching of the active paste of a nickel oxide electrode from a spent alkaline battery. The crystals were studied
by X-ray phase analysis in two measurement conﬁ gurations (transmission and Bragg–Brentano focusing).
In view of the inevitable exhaustion of natural
resources, a steadily increasing fraction of the raw
materials base on the market of manufacture and
consumption of nonferrous metals is constituted by
secondary raw materials. This can attributed in full
to the battery industry. In the world practice, the ratio
between the industrial applications of acid and alkaline
batteries is 4 : 1, whereas in CIS countries, this ratio is
2 : 1 because of the speciﬁ c technological equipment
in the industry and the transportation infrastructure
. Alkaline nickel-iron and nickel-cadmium batteries
contain large amounts of metals, such as nickel,
cadmium, and copper.
As the main source of secondary nickel serve nickel
oxide electrodes (NOEs) whose active paste contains
38.7– 39.1 wt % nickel .
Several technological schemes for processing of
worked-out alkaline batteries have been described in the
literature [3–5]. All these schemes include the following
procedures: dismantling of a battery, separation of plates
by chemical composition, leaching, and manufacture
of the ﬁ nal product, nickel(II) hydroxide. These
techniques, as a rule, differ in that a number of additional
technological procedures are performed to provide
a more complete recovery of the target component in
the course of leaching: thermal treatment of the active
paste and preliminary separation of carbon by ﬂ otation.
There exist two fundamentally different leaching
methods: acid-type (sulfuric acid leaching as a particular
case) and ammonia-type whose application does
not require any preliminary separation of the active
paste from lamels. However, a large amount of return
solutions is formed in the latter case because of the poor
solubility of nickel ammoniates in water. Moreover,
the ammonia leaching requires a hermetically sealed
apparatus because the ammonia pressure at leaching
temperatures is high. With the above factors taken into
account, a conclusion can be made that the efﬁ ciency of
sulfuric acid leaching is higher.
A number of crystal hydrates with different amounts
of water exist in the NiSO
O system at temperatures
in the range from 269.6 to 363 K. According to published
data , the following phases are stable: morenosite
O (rhombic), retgersite α-NiSO
(tetragonal), nickel hexahydrite β-NiSO
O, and dwornikite NiSO
O (n = 3–5) is metastable.
The crystallization of nickel sulfate from solutions
containing sulfuric acid, i.e., in the NiSO
system, has been studied at temperatures of 283–353 K
Nickel sulfate heptahydrate crystallizes at 283 K up
to a sulfuric acid content of 38.7 wt % in a saturated
solution. At 293, the threshold content of sulfuric acid