PROSPECTS FOR USING ALUMINOSILICATE REFRACTORIES
FOR ALUMINUM ELECTROLYZERS.
PART 2. RESISTANCE OF ALUMINOSILICATE REFRACTORIES
TO THE ACTION OF COMMERCIAL ELECTROLYTE
V. V. Sharapova,
B. P. Sereda,
D. Yu. Boguslavskii,
I. P. Malyshev,
V. D. Troyan,
and N. A. Troshenkov
Translated from Novye Ogneupory, No. 10, pp. 26 – 32, October 2007.
Original article submitted July 5, 2007.
Data are provided for laboratory studies of the resistance of aluminosilicate refractories to the action of com
mercial electrolyte. It is established that refractory ShPD
-45, prepared using a mullite-corundum chamotte,
is most resistant to electrolyte action. Results are provided for studies in the change of mineral composition
and phase transformations in aluminosilicate refractories during reaction with commercial electrolyte. It is
shown that long-prismatic titanium-containing mullite is more resistant to the action of the fluoride ion than
The service life of an aluminum electrolyzer is mainly
governed by the resistance of refractory linings of the cathode
assembly to the action of an incoming corrosive medium.
There is information about tests of refractory materials for
cryolite resistance. Different test procedures, their characte-
ristics and comparisons are provided in [1, 2].
Data from laboratory studies are provided in this article
for the resistance of aluminosilicate refractories ShA-5,
ShPD-43 and ShPD
-45  to the action of a commercial
electrolyte with a cryolite ratio (c.r.) of 2.4. Tests were per
formed by a petrographic method in reflected and transmit
ted light in MBI-6 and MIN-8 microscopes respectively.
The resistance of aluminosilicate refractories in contact with
molten commercial electrolyte was determined with a
steady-state method by heating test articles in a Tamman fur
nace followed by a study of the change in mineral and phase
composition of the refractories. Cylindrical holes of identical
diameter and depth were made in articles, and they were
filled with a uniform amount of commercial electrolyte with
c.r. of 2.4 containing, apart from the main components, cal
cium and magnesium fluorides. The prepared samples were
placed in a hermetically sealed alundum crucible and heated
in a Tamman furnace to 1000°C with isothermal soaking at
1000°C for 1 h. Cooling took place in the furnace.
After testing refractory specimens changed in color. At the
surface of specimens from the side of the opening reaction
zones were seen in the form of concentric circles of different
color. The diameter of the original hole increased (Fig. 1),
and its relative increase for specimens of ShA-5, ShPD-43,
-45 was 47.5, 33.3 and 16.1% respectively.
A specimen of ShA-5 after testing had a dingy lilac color.
Over its surface (at the top of the hole and over the side)
glassy new formations were seen in the form of circles with a
diameter of 4 mm and leakages from the direction of the depres
sion (hole), i.e. coarse pores with a diameter of 1.0 – 1.5 mm.
The electrolyte was converted into glass. With separation
over the length of the depression two zones seen: a working
zone 5 – 10 mm thick of green color, and a glassy and transi
tion zone yellow in color. The base of the specimen was the
least changed zone (Fig. 2a ).
A specimen of ShPD-43 after testing had a gray color.
At its surface from the direction of the hole in the form of
circles there was a working zone green in color and then
there was a transition zone (dark brown color) and a least
changed zone. With separation of a fired specimen of
ShPD-43 a glassy working zone green in color with a thick
ness up to 3 mm was seen, there was a transition zone of
yellow color with a thickness of 9 mm, and least changed
zone was gray in color (see Fig. 2b ).
A specimen of ShPD
-45 after testing had a gray color.
From the direction of the hole there were concentric circles
Refractories and Industrial Ceramics Vol. 48, No. 5, 2007
1083-4877/07/4805-0317 © 2007 Springer Science+Business Media, Inc.
Part 1 of the article was published in Novye Ogneupory No. 9 (2007).
UkrNIIspetsstal’, ZGIA, OAO ZAlK, OAO Zaporozhogneupor,