WATER-RESISTANT LIME-MAGNESIAN CLINKER
S. A. Suvorov,
M. I. Nazmiev,
R. S. Polovinkina,
and I. G. Maryasev
Translated from Novye Ogneupory, No. 9, pp. 38 – 40, September, 2006.
Original article submitted August 3, 2006.
A technological scheme has been developed for producing water-resistant lime-magnesian clinker and pow
ders based on high-purity dolomites, dolomitized magnesite, lime, chalk, calcium carbonate, and magnesium
without additives impairing the physicochemical properties of refractory materials. The hydration resistance
of clinkers and granular materials containing free CaO is determined by their high density, which is equal to
95 – 98% of the theoretical density. The properties of such clinkers and powders give reason to expect the pro
duction of functional lime-magnesian refractories whose properties in some cases are not inferior to peri
The production of water-resistant clinker containing free
CaO due to the formation of a high-density structure remains
a topical problem [1 – 4]. This is related to the extensive
available resources for lime-magnesian refractories and to its
economic advisability, taking into account the high refining
capacity of lime. To develop a technology for producing wa-
ter-resistant lime-magnesian clinker, we have used dolomite
from the Yekaterininskii deposit (city of Krasnoyarsk). The
dolomite has the following chemical composition (wt.%):
MgO 22.0 – 24.5, CaO 28.5 – 30.5, Al
0.07 – 0.25, SiO
0.22 – 0.95, Fe
0.16 – 0.45, MnO 0.07 – 0.10, Äm
45.0 – 45.5.
Dolomite was crushed to a fraction of 2.0–0mm in a
jaw crusher and a roll crusher until 100% dolomite passed
through a sieve with a 2.0-mm cell. A sintering-activating
additive was prepared by stepwise hydration of calcined do
lomite taking a theoretically required quantity of water until
the formation of Mg(OH)
. Milling was per
formed in an M-400 vibration mill until 98% of the dolomite
passed through a sieve cell of 0.0063 mm.
Mixtures were prepared in a mixer produced by the
Eirich company. Mixing of one batch lasted 15 min. The
mixture was visually homogenous and easily moldable. Two
compositions of mixtures were prepared. Mixture D-1 con-
tained 80% finely milled raw dolomite, 20% activating addi-
tive, and 2.5 – 3.0% (above 100%) plasticizer. Mixture D-2
contained 100% finely milled dolomite and 2.0 – 2.5%
(above 100%) plasticizer.
An ellipsoid briquette with a larger axis of 25 mm and a
smaller axis of 15 mm was molded on a 72/8-3A35D G-1S
roller press under the conditions specified in Table 1.
Due to the introduction of the plasticizer, the share of in
teger briquettes with respect to crumbles is 80 – 90%, which
is approximately twice as much as when briquetting mixtures
without a plasticizer.
To gather strength, briquettes of mixtures D-1 and D-2
aged for 7 days (Table 2). On the second day of aging, the
strength of the briquette decreased. On the 7th day, the bri
quette of mixture D-1 (with the sintering-activating additive)
gathered strength due to the formation of calcium and mag
nesium hydrocarbonates. The strength of the briquettes al
lowed them to be fed into a shaft or a rotary furnace (the bri
Refractories and Industrial Ceramics Vol. 47, No. 5, 2006
1083-4877/06/4705-0291 © 2006 Springer Science+Business Media, Inc.
St. Petersburg State Technological Institute (Technical Univer
sity), St. Petersburg, Russia; Magnezit Works, Russia.
TABLE 1. Operating Roller Press in Molding Mixtures
Parameter Mixture D-1 Mixture D-2
Rotational speed, rpm
rollers 5 6.4
additional press 6 6
Strength of current, A 400 420
TABLE 2. Strength of Briquettes from Mixtures D-1 and D-2 De
pending on Aging Duration
Compressive strength of briquette, MPa, after
1 day 2 days 7 days
D-1 14.1 10.2 17
D-2 14.2 12.3 10.1