STUDY OF THE EFFECT OF pH REGULATORS AND POLYELECTROLYTES
ON LITHIUM-ALUMINUM SILICATE GLASS AQUEOUS SUSPENSION
PARAMETERS AND CASTING PROPERTIES
E. I. Suzdal’tsev,
T. V. Zaichuk,
Yu. S. Ustinova,
and S. N. Vandrai
Translated from Novye Ogneupory, No. 2, pp. 20 – 24, February, 2016.
Original article submitted September 2, 2015.
Wet milling is used to prepare lithium-aluminum silicate glass suspensions. The possibility is studied of using
electrostatic and electrosteric stabilization methods for controlling aqueous suspension parameters with the
aim of reducing the duration of green workpiece setting with required density and porosity. Additives used are
orthophosphoric and hydrochloric acids, aqueous ammonia solution, and also polyacrylic acid (PAA), and
PAA sodium and ammonium salts.
Keywords: highly concentrated ceramic binder suspensions (HCBS), slip casting, lithium-aluminum silicate
(LAS) glass, electrostatic stabilization, electrosteric stabilization, setting duration, casting porosity.
Preparation of stable highly concentrated aqueous sus-
pensions based on glass powders is an important task for ad-
vanced technology of glass ceramic material manufacture, in
particular preparation of workpieces for radio engineering
purposes by aqueous slip casting. A study of the effect of dif-
ferent additives on suspension (slip) properties and casting
setting duration makes it possible to improve comminution
of the starting material and preparation of mixes for molding
casings, and to optimize manufacturing technology for glass
ceramics with required properties.
Processes for preparing high-density aqueous suspen
sions based on LAS glass, intended for molding large comp
lexly-shape workpieces, has been studied carefully in . On
the basis of results obtained technology had been developed
for preparing workpieces, including slip preparation and
molding workpieces of arbitrary dimensions, and repeated
processing of workpieces into slip for molding objects. It has
been shown that molding objects from slip, prepared in the
first stage (primary slip), is difficult due to its increased ten
dency towards thixotropic flow, it takes quite a long time,
and the quality of workpieces obtained does not correspond
to that required. Slip prepared by reprocessing castings,
molded from primary slip (secondary slip), develops a
thixotropic-dilation flow nature in contrast to the finely dis-
persed nature of the first. Workpiece formation occurs signif-
icantly more quickly, and castings have low porosity. None-
theless, as usual it is important to exclude secondary treat-
ment from technology for preparing glass ceramic
workpieces and to shorten the production cycle for object
manufacture as a whole.
The aim of this work is to study the possibility of mold
ing workpieces from a primary LAS glass slip with low po
rosity and high density. For this the effect of pH regulators
was studied in the form of orthophosphoric and hydrochloric
acids, and aqueous ammonia solution, and also polyacrylic
acid and polyacrylates on slip properties, setting (molding)
duration, and molded workpiece properties.
It is well known that for casting high quality workpieces
suspensions are necessary with certain solid phase particle
grain size distribution, providing the best particle dense
packing, a suitable solid mix assembly rate for a workpiece,
and uniform solid phase distribution throughout the volume
. Solid phase particles of suspensions are in a suspended
state in a liquid dispersion medium. In this system bonding
between particles is accomplished by van der Waals molecu
lar forces and article surface charges operating through thin
water films covering their surface . The surface of solid
phase particles is electrically active, with a capacity to at
tract, and then to absorb ions from a dispersion medium.
Refractories and Industrial Ceramics Vol. 57, No. 1, May, 2016
1083-4877/16/05701-0065 © 2016 Springer Science+Business Media New York
GNTs RF AO ONPP A G. Romashin Technology, Obninsk, Kalu
ga Region, Russia.