EFFECTS OF DISPERSANT FORM
AND AMOUNT ON THE PROPERTIES OF VIBROCAST
PERICLASE-SPINEL MATERIAL FOR MAKING CRUCIBLES
V. V. Primachenko,
V. A. Ustichenko,
S. V. Chaplyanko,
and E. Yu. Solod
Translated from Novye Ogneupory, No. 12, pp. 24 – 27, December, 2008.
Original article submitted July 3, 2008.
The effects have been examined from the form and amount of dispersant on the flow of suspensions based on
microgranular periclase, and also the fluidity in the vibration of granular periclase-spinel materials. The best
form and amount have been established for dispersants that provide the required flow at various environmen
tal temperatures in the vibration of the granular periclase-spinel materials of water content 5.0 – 6.5% and
working time not less than 3 h.
Crucibles of mullite-corundum, corundum-spinel, and
corundum-periclase compositions as made by the present
company [1 – 3] are employed in the Ukraine for the induc-
tive melting of heat-resistant nickel and cobalt alloys. When
iron alloys are melted, or alloys and steels with high contents
of corrosive components that are responsible for rapid refrac-
tory wear, it is recommended that crucibles based on
periclase should be used [4, 5]. To melt these alloys, the pres
ent company has developed vibrocast crucibles of
periclase-spinel composition .
A substantial shortcoming of periclase is that it becomes
hydrated not only in water but also in air [7, 8]. This is ac
companied by a volume increase by a factor 1.97 – 2.17, and
the hydration rate increases with temperature . To reduce
these effects, special bonding agents are used that have a hy
drophobic effect, and the powders are treated with surfac
tants [10 – 12] or additional heat treatment is applied to the
plagioclase with the addition of talc . However, one can
not completely eliminate the effect of hydration, so a very
complicated process is involved in making periclase and
periclase-bearing refractories, particularly by vibrocasting.
The present study was intended to determine the form
and amount of dispersant that reduces the hydration of
periclase and gives a vibrocast granular periclase-spinel ma
terial with a vibrational activity time (viability) not less than
3 h. We examined the effects of the dispersant form and
amount on the suspension flow time for a microgranular
component of the charge: fused periclase, as well as the vi-
brational activity time of the periclase-spinel material.
The raw materials were fused periclase and spinel,
whose chemical compositions are given in Table 1. The pow-
ders were used in granular and finely divided forms.
An Engler flow viscometer was used to determine the
suspension flow time for a microgranular component of the
charge: fused plagioclase of fraction less than 0.063 mm
[pp. 83 – 85 of . To reduce the measurement error, the to
tal suspension volume was 200 ml for the determination of
the suspension flow time on a volume of 100 ml.
We determined the suspension flow time for a given wa
ter content and the flow time with a threshold water content
for suspensions with various dispersants. The flow time with
the threshold water content was determined from the instant
when the suspension acquired fluidity, where it flowed con
tinuously through the hole in the viscometer. We also re
corded the viability time, i.e., the time during which the sus
Refractories and Industrial Ceramics Vol. 49, No. 6, 2008
1083-4877/08/4906-0482 © 2008 Springer Science+Business Media, Inc.
Berezhnoi UkrNIIO Company, Kharkov, Ukraine.
TABLE 1. Compositions of Raw Materials
Composition, wt. %
Periclase 0.94 0.38 0.77 1.31 96.60
Aluminum-magnesium spinel 0.24 83.76 0.15 0.25 15.60