Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 2, pp. 337−339.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
E.N. Volkova, A.I. Demidov, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 2, pp. 343−345.
Determination of Nickel in the Solution Resulted
from Sulfuric-Acid Leaching of the Active Mass
of the Nickel-Oxide Electrode of the Nickel-Iron Battary
E. N. Volkova and A. I. Demidov
St. Petersburg State Polytechnical University, St. Petersburg, Russia
Received January 13, 2009
Abstract—A nickel content was determined in the solution resulted from sulfuric-acid leaching of the active
mass of the nickel-oxide electrode of an exhausted nickel-iron battery by complexometric titration with visual
indication of an equivalence point.
At present appreciable attention is given to secondary
processing of wastage containing non-ferrous metals,
the preference being given to hydrometallurgical
methods, which are the most harmless and less energy-
A hydrometallurgical technology of secondary
processing of nickel-iron batteries (NIB) was offered
in . One of its key points was the active mass (АМ)
leaching by a 200-300 g l
(17−26 wt %) sulfuric acid
Hydroxides of nickel(II) and (III) are the main
components of the active mass of the nickel-oxide
electrode of the exhausted nickel-iron battery. In addition
a signiﬁ cant amount of iron and carbon compounds and
a solid residue of the electrolyte (sodium hydroxide and
carbonate) are present there. The active mass can be
polluted by copper, sulfur, phosphorus, and tin in the
form of trace admixtures with the contents of hundredths
or thousandths shares of percent . In most cases, the
presence of trace contaminants does not essential by
affect the determination of macrocomponents, however,
certain analytical procedures require a careful selection
of experimental conditions for obtaining reproducible
Depending on the quantitative nickel content in
a sample under study the analysis is carried out by
various methods: gravimetric, volumetric (titrimetric),
or photometric [4, 5].
One of known volumetric methods of nickel determina-
tion is the complexometry. This method is based on the
formation of complex compounds of sodium ethylene
diamine tetraacetate (EDTA, Trilon B, or complexon III)
with nickel ions in the presence of an indicator changing
its color in an equivalence point (e.p.).
The values of the instability constants of nickel(II)
complexes with EDTA р
= 11.56 and HEdta
18.62  suggest that a great number of cations of other
metals will hinder the determination of nickel.
However, despite of it, the complexometric titration
ﬁ nds practical application for the determination of nickel
in plating baths , alloys with copper and other non-
ferrous metals , and in condensation polymers .
In this work it was of interest to determine the nickel
content in a solution of complex composition, without
its preliminary separation in the form of an organic
complex and without masking iron, which is the main
admixture that should be removed in the sulfate form at
the secondary extraction of nickel from the nickel-oxide
electrode active mass.
Choice of an indicator and experimental conditions.
The following indicators can be used in the complexometry
of nickel [6, 10]: murexide, 1-(2-pyridylazo)-resorcinol