PREPARATION OF FUSION-CAST CHROMIUM-SPINELID
REFRACTORIES USING VESSEL SCRAP
V. A. Sokolov,
M. D. Gasparyan,
and S. S. Kirov
Translated from Novye Ogneupory, No. 3, pp. 160 – 164, March, 2013.
Original article submitted November 20, 2012.
Results are provided for preparation of fusion-cast chromium-spinelid refractories using lumps of
baddeleyite-corundum refractory waste after service in glass melting furnaces. It is shown that fusion-cast
chromium-spinelid refractories, containing 31.2 and 50.4% Cr
and prepared from a charge using broken
vessel refractory, has improved corrosion resistance in molten mineral wool compared with fusion-cast
baddeleyite-corundum and chromium-aluminum-zirconium refractories of commercial grades ER 1711,
KhATs-30, and KhTs-45.
Keywords: fusion-cast refractories, chromium-spinelid, chromium-corundum, baddeleyite, broken vessel,
corrosion resistance, glass melting furnace.
Fusion-cast chromium-containing refractories are most
corrosion-resistant to action of mineral melts at high temper-
ature. In the manufacture of these high chromium
refractories such as KhPL-85 and KhMG  raw materials
of commercial grade purity are used: chromium oxide, zirco-
nia concentrate, and clay, which makes production more ex-
pensive. Nonetheless these requirements for raw material pu-
rity should be maintained with use of refractories during spe
cial production: preparation of borosilicate glass type E and
sitallizing lead-niobium glass, and utilization of radioactive
waste. At the same time, there are a number of products for
which there are no special requirements for purity of refrac
tory raw materials and the main specification for these
refractories is high corrosion resistance.
Mineral wool production is a notable user of fusion-cast
vessel materials, but with a considerable shortage of zirco
nia-containing raw material the demand for it is not satisfied.
Vessel refractories used in mineral wool production do not
provide a long campaign for glass-melting furnaces, which in
the majority of enterprises only last one year. An alternative
to fusion-cast vessel and high-chromium refractories may be
materials prepared from raw material based on baddeleyite-
corundum refractory waste.
The aim of this work is preparation of fusion-cast chro
mium-spinelid refractories using a charge of waste lump
baddeleyite-corundum refractory after service in glass-melt-
Ground scrap baddeleyite-corundum refractory is used
for refractory synthesis with an average composition (ZrO
O 2.3%, other oxides
1.9%), and also chromium oxide grade OKhM-1 (GOST
2912) with a Cr
content of 98%, and chemically pure
magnesium oxide containing 99% MgO. Chromium and
magnesium oxides are added to the refractory charge in an
amount 79.2 and 20.8% respectively, providing a calculated
spinelid composition MgCr
. It is necessary to consider
actual redistribution and reaction of these oxides with alumi
num, silicon, sodium, and other oxides during melting and
material crystallization. Charge compositions for melting
and fuzed material composition are provided in Table 1.
Melting of chromium-spinelid refractory charges was
carried out in an electric-arc industrial test unit ÉPD-400 .
Melt was poured into casting molds assembled from sand
plates 50 mm thick (castings M1, M2, and M3) and graphite
plates 50 mm thick (castings M4, M5, and M6), and placed in
a heating cabinet with a diatomite heat insulating cover. Sand
mold internal dimensions were 200 ´ 200 ´ 500 mm, and for
graphite they were 200 ´ 300 ´ 500 mm.
After measurement, weighing, and visual examination
castings were cut over the longitudinal section for revealing
internal defects and analyzing features of the crystal struc
ture. Specimens were cut from the working area for
physicochemical and operational studies. The weight of cast
Refractories and Industrial Ceramics Vol. 54, No. 2, July, 2013
1083-4877/13/05402-0095 © 2013 Springer Science+Business Media New York
NITU MISiS, Moscow, Russia.
OOO TsIT SPETsKEROKOM, Podol’sk, Russia.