ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 9, pp. 1447!1452. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + A.R. Kobeleva, V.Z. Poilov, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 9, pp. 1409!1415.
AND INDUSTRIAL INORGANIC CHEMISTRY
Technology for Production of Calcium Carbonate
with Prescribed Properties
A. R. Kobeleva and V. Z. Poilov
Perm State Technical University, Perm, Russia
Received October 30, 2006; in final form, March 2007
Abstract-Physicochemical conditions for production of calcium carbonate with prescribed size and shape of
particles and crystal structure by reaction of CaCl
solutions were studied. A technology for
manufacture of calcium carbonate with prescribed properties was developed.
Calcium carbonate and products obtained from this
compound are widely used in various fields of econ-
omy: in building, as a component of finishing materi-
als; for manufacture of cement, glass, and ceramics;
in pharmacology, to manufacture toothpastes and
antacid preparations; in cosmetics, to produce creams;
in water treatment, as filter materials; in paper in-
dustry, to manufacture cigarette, chalk-overlay, and
tracing paper; in production of plastics and artificial
leather; finely dispersed powdered chalk serves as
a filler or pigment in cable, paint-and-varnish, poly-
mer, rubber, and petrochemical industry; etc.
In all these fields, various requirements are im-
posed on calcium carbonate: on its chemical composi-
tion and size and shape of crystalline CaCO
on which depend the commercial characteristics of
calcium carbonate and fields of its use (Table 1).
Technologies for production of precipitated calci-
um carbonate from various raw materials: natural car-
bonates and solid carbonate wastes and solutions,
have been and are being developed. Different proc-
esses are used, depending on a starting raw material
and requirements to the final product. A technology
widely used in Russia is that in which calcium carbo-
nate is produced by carbonation of a Ca(OH)
sion with carbon dioxide, with the subsequent separa-
tion of the precipitate from the solution and drying
and calcination of the resulting product [13 4]. A dis-
advantage of this technology is that it is difficult to
obtain the CaCO
product with prescribed properties.
Of practical interest is development of a technique
based on CaCO
precipitation in a chemical reaction
of technical soda Na
and a CaCl
produced from waste formed in manufacture of soda
ash (distiller fluid) or by dissolution of natural chalk.
The main development direction of this technology is
production of calcium carbonate with prescribed
physicochemical properties (definite particle size and
shape, crystal structure, impurity content).
The process of calcium carbonate synthesis in-
cludes the chemical reaction
2 + 2NaCl.
In this study, we examined conditions in which
calcium carbonate is obtained in different reactant
supply modes, ion concentration ratios [Ca
starting reactant concentrations, temperatures, and
hydrodynamic modes of chemical precipitation of
in the presence of various modifiers.
In the batch mode of chemical precipitation of
, a certain amount of a calcium chloride or
soda solution was poured into the reactor and heated
to a certain temperature, after which the second reac-
tant was fed at a constant rate by a peristaltic pump.
In the continuous mode of CaCO
synthesis, the reac-
tants were permanently fed by pumps at a constant
rate into the reactor filled to the stirrer blade level
with distilled water. The process was performed with
agitation during a certain time at a constant rate of
rabble rotation. The resulting CaCO
filtered off and washed on the filter with distilled
water. The calcium carbonate paste was dried in
a drying box at 100oC. The dried calcium carbonate
was examined with a KS optical microscope at a
15000 magnification in transmitted light. Photo-
microscopic studies were performed by photographing
microcrystals with an Olympus C 500 digital