SCIENTIFIC RESEARCH AND DEVELOPMENT
THINNING, PLASTIFYING, AND STRENGTHENING ADDITIVES
AS EFFECTIVE MODIFIERS IN HCBS AND CERAMIC
Yu. E. Pivinskii
Translated from Novye Ogneupory, No. 1, pp. 16 – 23, January, 2012.
Original article submitted July 27, 2011.
The efficiency of using thinning (deflocculating), plastifying, and strengthening additives in HCBS technol
ogy, ceramic concretes, and new unmolded refractories, is demonstrated. Quantitative criteria are proposed for
evaluating additive efficiency. In the field of preparing the materials in question the practice of using compos
ite (combined) modifying (deflocculating) additives that have a high synergetic effect predominates. They are
distinguished by an electrosteric stabilization mechanism. Solutions or powders, used in the preparation of un-
fired materials, strengthened by a UKhAKS-mechanism (strengthening by chemical activation of contact
bonds), are a special group of additives.
Keywords: thinning, deflocculation, plastification, water glass, silicate lump, UKhAKS (strengthened by
chemical activation of contact bonds)-materials, synergetic effect.
WATER GLASS SOLUTIONS AND SODIUM
METASILICATE POWDER IN HCBS AND
Water glass solutions are one of the thinning additions
most in demand in HCBS technology for acid and
acid-amphoteric compositions [1 – 5]. For the latter group of
HCBS the optimum rheotechnological properties are
achieved with a value of pH=8–9,which during wet grind
ing is obtained and maintained by introducing water glass
additive whose content, depending on chemical composition
and purity, may vary within considerable limits, i.e., from
0.02 to 0.3% (for dry substance). The minimum amount of
additive is used during wet grinding of HCBS of mixed com
position in a bauxite-VFQG system, and the maximum
amount is used with alkaline activation of quartz glass HCBS
used in technology for unfired quartz refractories of hydro
thermal strengthening [3, p. 77]. In preparing UKhAKS-ma
terials in activating the strengthening process the effective
additives used are not only low-concentration water glass so
lutions, but also sodium metasilicate powder (silicate lump
ground to d
= 100 – 200 mm).
Due to the multifunctional nature and broad field of ap-
plication for water glass it may be classified as the most
widespread synthetic silicate material [24, 25]. Its use as a
binder is very extensive [25 – 28]. Water glass is considered
as a air-hardening binder. The binding properties are due to
the polymeric nature, which makes it possible during drying
to form a quite rigid and strong polymeric carcase [26, 27].
A feature of the use of water glass for UKhAKS-
strengthening consists of the fact that in this case it is used
primarily as an alkaline component, governing the dissolu
tion mechanism for SiO
-containing materials followed by
condensation of the interstitial solution formed. In order to
confirm this assumption it is possible to refer to the
well-known comparative experimental data for strengthening
by the UKhAKS-mechanism of unfired quartz ceramic by
treatment in water glass solutions and commercial grade
soda [1, 2]. Comparable strength data with different strength
ening conditions were achieved using water glass solution
(density 1.2 – 1.5 g/cm
, pH = 11.5 – 11.7) and commercial
grade soda solution with a concentration of about 5%
(pH = 11.0 – 11.0). An advantage of using water glass solu
tion over soda for this case consists of the fact that a consid
Refractories and Industrial Ceramics Vol. 53, No. 1, May, 2012
1083-4877/12/05301-0012 © 2012 Springer Science+Business Media, Inc.
Continuation. Started in No. 2, 11 – 16 (2011).
OOO NVF Kerambet-Ogneupor, St Petersburg, Russia.