CONTEMPORARY ALUMINUM ELECTROLYZER
V. Yu. Bazhin,
D. V. Makushin,
and Yu. N. Gagulin
Translated from Novye Ogneupory, No. 9, pp. 13 – 15, September 2008.
Original article submitted March 10, 2008.
The problem of refractory materials for lining the cathode casing of contemporary electrolyzers with a power
of 300 – 500 kA, closely connected with the service life of the electrolyzer bath, is discussed. For this purpose
it is possible to use plates of the composition SiC–Si
, artificial build-ups of ramming mix, and also TiB
more effective protection and operation of aluminum electrolyzers that are favorably reflected in the produc
tion regime and optimization of production.
At the beginning of the second half of the twentieth cen-
tury the aluminum industry developed in different directions,
but the consequences of the developments of constructors
and technologists of different companies acquired a common
character. All of the innovations were directed at increasing
the size of an electrolyzer, that invariably led to an increase
in thermodynamic efficiency and a reduction in capital ex-
penditure per ton of installed power.
The cathode unit of an electrolyzer is a steel casing filled
with carbon and refractory lining materials. The lining of an
electrolyzer consists of a socle, a hearth and side lining. The
socle contains the heat insulating and refractory layers. In the
side lining there are plates of SiC-Si
composition and ar
tificial build-ups of rammed mixes that effectively take off
heat from the side walls and form the profile of the build-up.
The side lining is made from silicon carbide plates that pre
vent its chemical and physical wear as a result of creating a
protective coating and minimizing plate oxidation by air. The
necessary attachment with the casing walls and also exclu
sion of a gap between the peripheral part of the socle and the
silicon carbide plates is provided by chamotte aluminosili
cate mortar. Between the cathode blocks and the heat-insulat
ing hearth there is use of dry impermeable material making it
possible to reduce the action of hearth deformation on the
cathode structure. Thermal insulation is made from vermicu
lite plates exhibiting a high resistance to electrolyte, and the
plates are laid in several rows on poured material of chamotte
filler. The refractory layers are made from chamotte brick and
they are protected by a layer of dry barrier mix, i.e. DBM.
After lining assembly the hearth is produced from carbon-
graphite blocks. The hearth is made is made from cathode
sections with a monolithic graphite block and composite
cathode rods fastened to the block by means of iron.
The lining construction for an electrolyzer with a power
of 400 – 500 kA is determined by heat energy calculation
made using a special computer program that determines the
amount of refractory material required. Currently there is
predominantly use of transversely arranged electrolyzers in a
building since it simplifies compensation of the magnetic
fields, and makes it possible to utilise an area and ancillary
equipment more effectively.
There are marked or insignificant differences in
electrolyzers of different construction in relation to the fol
lowing main elements: the base of an electrolyzer and its side
cooling system, construction of the cathode casing (rein
forced and end walls), the socle with new lining materials
and coatings, the shape and size of cathode blocks and cath
ode rods, the depth of the cathode casing and the thickness of
the heat insulating layer. Since each of these elements affects
electrolyzer operation, it is necessary to answer the question;
are there limitations for the use of the best versions for each
of the elements listed above in the construction of existing
electrolyzers or the creation of new constructions? Modern
ization of electrolyzer construction is carried out so that for a
new anode construction it would be possible to use the ap
propriate cathode casing with a lining.
Recently there has been a change in ideas about capital
investment and many aluminum plants have increased their
profit as a result of increasing the current strength. However,
an increase in the working current strength to 400 – 500 kA
unavoidably leads to new structural work for cathode unit as
semblies of an aluminum electrolyzer, that are partly sub
Refractories and Industrial Ceramics Vol. 49, No. 5, 2008
1083-4877/08/4905-0334 © 2008 Springer Science+Business Media, Inc.
OAO RUSAL VAMI, Chelyabinsk, Russia.