1070-4272/01/7403-0386$25.00C2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 3, 2001, pp. 386 !389. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 3,
2001, pp. 379!383.
Original Russian Text Copyright + 2001 by Tsemekhman, Tsymbulov, Ryabko, Mamyrin, Blatov, Velim.
AND INDUSTRIAL INORGANIC CHEMISTRY
Fractionation of Sulfur Isotopes in the Course
of High-Temperature Roasting of Copper!Nickel Sulfide Ores
L. Sh. Tsemekhman, L. B. Tsymbulov, A. G. Ryabko, B. A. Mamyrin,
I. A. Blatov, and V. S. Velim
Gipronikel’ Institute, Joint-Stock Company, St. Petersburg, Russia
Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, Russia
Kola Mining and Smelting Company, Joint-Stock Company, Murmansk, Russia
Received November 29, 2000
Abstract-The fractionation of sulfur isotopes, namely, enrichment of the cinder with the heavy isotope
in the course of roasting of various sulfide ores and concentrates in neutral and oxidative atmospheres at
7733973 K was studied.
High-temperature oxidative roasting is widely used
today as one of main overhead stages in processing
copper3nickel and copper sulfide concentrates. There-
fore, roasting processes attract steady researches’ in-
terest. A significant attention is paid to the mech-
anisms of oxidation and dissociation of sulfur,
is the major component removed upon the roasting.
It is well known that isotopes can be fractionated in
the course of chemical reactions, i.e., fractions of
isotopes in products can differ from those in the start-
ing reagents. Therefore, it is not improbable that
studying the fractionation of sulfur isotopes can give a
new qualitative information on reaction mechanisms,
as compared to traditional techniques (chemical analy-
sis, XRD, X-ray spectral microanalysis, etc.).
The fractionation of sulfur isotopes in the course of
high-temperature oxidative roasting of copper3nickel
sulfide ore of Pechenga ore field was established
previously . However, the data obtained could not
be considered as fully reliable because of insufficient
number of the experiments.
In this work the possibility of fractionation of sul-
fur isotopes was confirmed not only for sulfide ores
but also for Pechenga ore concentrates and natural
pyrite at various temperatures in oxidative and neutral
Oxidation of sulfur and dissociation of higher sulfides can oc-
cur simultaneously in spite of the fact that roasting is carried
out in an oxidative atmosphere.
The composition of starting materials is given in
Table 1. Pyrite was roasted at 773 and 873 K under
argon in an installation shown in Fig. 1.
A 5-g pyrite sample in an alundum boat was first
placed in a quartz tube and then in a furnace with a
Silit heater. The tube was blown through with argon
before switching on the furnace. On reaching a tem-
perature of the experiment the quartz tube was moved
to place the sample in the furnace hot area. In the
course of the experiment the temperature was kept
constant by an automatic apparatus. After roasting the
sample was removed from the hot area by shifting the
tube. The furnace was switched off, but the gas was
passed through up to complete sample cooling.
After thorough grinding and mixing, the cooled
sample was divided into two equal parts. One of them
was chemically analyzed for the total sulfur and sul-
fate sulfur. The other part was used in the isotope
Copper3nickel sulfide ore and concentrate were
roasted in air at 823 and 973 K. Preliminarily the ore
and concentrate with the grain size less than 0.1 mm
were pelletized with water added. A 4-g pellet sample
was placed in a quartz reactor roughly modeling a
fluidized-bed furnace (Fig. 2). The reactor was placed
in a Silit furnace and heated. On reaching the required
temperature, air was passed through the reactor bot-
tom at a rate of 1.35 l min
. The oxidation time was
varied from 1 to 15 min. On completion of the ex-
periment, the air flow was ceased and the reactor