1070-4272/02/7501-0014$27.00C2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 1, 2002, pp. 14!17. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 1,
2002, pp. 15!18.
Original Russian Text Copyright + 2002 by Malysh, Gaisin, Volkova, Prokhorov, Tkachev.
AND INDUSTRIAL INORGANIC CHEMISTRY
Reduction of Recycled Barium Sulfate
L. A. Malysh, L. G. Gaisin, M. F. Volkova, A. G. Prokhorov, and K. V. Tkachev
Ural Research Chemical Institute with Experimental Plant, State Unitary Enterprise, Yekaterinburg, Russia
Karpov Chemical Plant, Joint-Stock Company, Mendeleevsk, Tatarstan, Russia
Received May 20, 2001
Abstract-Barium sulfate, which is recycled according to a new flowsheet of sodium sulfide production, was
reduced by various carbon-containing materials (oil and furnace coke and Zh-grade coal). The reduction
process was studied in comparison with the reduction of natural barite concentrate.
Sodium sulfide used in concentration of non-
ferrous metal ores, dyeing of fabrics, dressing of
leather, and also in production of dyes, soda products,
cellulose, and glass is presently produced in Russia by
the reduction of packaged sodium sulfate by furnace
coke in shaft furnaces . This process is now out of
date; it does not meet modern requirements to the
environmental protection and to the product quality
and is characterized by low utilization of the raw
A new low-waste technology is based on obtaining
sodium sulfide by the reaction [2, 3]
BaS + Na
Barium sulfide is regenerated by reductive roasting of
the forming barium sulfate, and, therefore, a barium
raw material theoretically is not consumed, and only
its loss should be replenished. The reductive roasting
of natural barite raw material is widely used in in-
dustrial production of barium salts.
The regeneration of barium sulfide is a key stage
of the new process; therefore, we have carried out
laboratory studies with the aim to reveal features of
the reduction of barium sulfate formed by reaction (1)
with various reducing agents (oil and furnace coke
and Zh-grade coal).
The reduction of barium sulfate with carbon has
been described in sufficient detail . According
to modern views, this process involves stages of solid
carbon gasification (2) and barium sulfate reduc-
= 2CO, (2)
+ 4CO = BaS + 4CO
The overall process is expressed by the total reaction
+ 2C = BaS + 2CO
The following reactions yielding acid-soluble barium
compounds occur concurrently:
+ C = BaSiO
+ CO, (5)
BaS + CO
O = BaCO
It is noted  that the reduction of barium sulfate
is intensified as soon as the first particles of barium
sulfide are formed, as they catalyze the process simi-
larly to calcium and sodium sulfides in the case of
the reduction of sulfates of these metals.
To obtain a comparative pattern, we have carried
out experiments with charges containing either barite
concentrate (BC) or recycled barium sulfate, with
reducing agent dosages being 125 and 155% of the
stoichiometric amount according to Eq. (4).
The chemical compositions of the raw materials are
given in Table 1. The dispersity of all the components
was 0.25 mm.
Reductive roasting of charges was carried out
under static conditions in a muffle at 1000oC for
30 min in alundum crucibles closed by lids. These
conditions suppress the secondary reactions of barium
sulfide carbonation and oxidation, and also prevent
burning-out of carbon-containing materials. The re-
sulting melt was cooled in a desiccator and analyzed.
We determined the content of BaS and BaS
iodometric titration, of water-soluble (ws) and acid-