ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 6, pp. 1025!1027. + Pleiades Publishing, Inc., 2006.
Original Russian Text + A.I. Demidov, M.S. Kokhatskaya, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 6, pp. 1035!1037.
Kinetics of the Reaction between the Active Paste
from the Positive Electrode of a Dead
Nickel!Iron Battery and Sulfuric Acid
A. I. Demidov and M. S. Kokhatskaya
St. Petersburg State Polytechnic University, St. Petersburg, Russia
Received May 24, 2006
Abstract-The kinetics of dissolution of a powdered active paste from the positive electrode of a worked-
out nickel3iron battery in 0.1 N sulfuric acid at 25, 50, and 75oC was studied by measuring the electrolyte
In continuation of previous publications [1, 2], we
present the results obtained in studying the reaction
between a powdered active paste from the positive
electrode of a worked-out nickel3iron (NI) battery
and sulfuric acid in the temperature range 25375oC.
The active paste was taken from worked-out NI bat-
tery of the TNZh-250-U2 type, the particle size of
the powder did not exceed 200 mm.
The overall reaction that occurs in charging and
discharge of a NI battery can be represented by
2NiOOH + Fe + 2H
O = 2Ni(OH)
It follows from this equation that the worked-out
active paste from the positive electrode should contain
and NiOOH. An X-ray diffraction analysis
revealed graphite and dispersed nickel hydroxide
in the active paste. An X-ray diffraction pat-
tern of the powdered active paste from a worked-out
NI battery is shown in Fig. 1.
In hydrometallurgical processing of worked-out
electrodes, it is necessary to know the content of
sodium or potassium carbonate and hydrocarbonate
remaining in pores of the active paste, because their
amount affects the expenditure of sulfuric acid for
processing of worked-out positive electrodes contain-
Fig. 1. X-ray diffraction pattern of the powdered active paste from the positive electrode of a worked-out TNZh-250-U2 nickel3
iron battery. (I) Intensity and (2q) Bragg angle.