PHOSPHATE-CONTAINING REFRACTORY COMPOSITE MATERIALS
Yu. N. Trepalina,
E. I. Evtushenko,
and V. A. Doroganov
Translated from Novye Ogneupory, No. 1, pp. 39 – 42, January, 2016.
Original article submitted March 6, 2015.
Development of new highly efficient composite materials is an important area for effective activity of refrac
tory enterprises. It is established that use of binder suspensions as both a mix component, and as an independ
ent material, makes it possible to expand the field of developed material application. The efficiency of using
corundum coatings increases heating unit service life.
Keywords: mechanochemical activation, phosphate-containing binder, electromelted corundum, ortho
phosphoric acid, ultimate strength in compression, open porosity, corrosive atmosphere resistance.
In view of a reduction in the volume of refractory pro-
duction in the Russian Federation a requirement arises for
developing new highly efficient composite materials capable
of replacing existing materials. The field of application of vi-
bration thixotropic mixes, apart from monolithic refractories,
is most promising for preparing large shaped concrete ob-
jects. A disadvantage of these concretes based on phosphates
is reduced thermomechanical properties. It is possible to im-
prove them by using mechanochemical phosphate-containing
binders. Concretes based on binder suspensions have a low
This aim of this research is to develop refractory mixes
used for preparing objects with improved operating proper
ties. The possibility has been studied of using binder suspen
sions as protective coatings , preventing refractory break
down during action upon them of high temperature and cor
rosive media. In order to achieve the stated purpose the fol
lowing were carried out:
– combined study of structural and mechanical proper
ties of binders based on phosphate-containing materials, de
velopment of molding conditions, and evaluation of material
– development of compositions and technology for co
rundum binder suspensions and coatings with a limited phos
phate-ion content for refractory protection during action on
them of high temperature and corrosive media;
– study of the resistance to corrosive media of the mate-
rial developed and coatings based on binder suspensions.
The starting materials used for study were substances of
natural (refractory clay) and engineering origin (electro-
melted corundum). According to GOST 28874 refractory un-
fired unmolded powder, mixes, and masses include refrac-
tory filler and binder that are capable of setting and harden
ing at quite low temperature with formation of a structure re
taining strength properties on heating. Phosphate binders are
heterogeneous systems. Aluminate binders form with reac
tion between alumina materials and orthophosphoric acid.
A change in preparation conditions may affect powder activ
ity [2, 3].
We consider an example of reaction of finely milled
electrocorundum fraction finer than 0.5 mm with ortho
phosphoric acid at 20 – 25°C, when acid aluminum phos
phate soluble in water forms whose amount increase during
suspension. A titration method was used to determine reac
tion kinetics for H
with dispersed phase in relation to
milling duration. Result of studies showed that the amount of
reacted acid depends on milling conditions (combined or
separate followed by suspension). Reaction intensity for
orthophosphoric acid with corundum shows that formation
of aluminum phosphate proceeds more actively in the initial
stage o combined milling, i.e., up to 23% in the first 8 h
(Fig. 1). With separate milling followed suspension the reac
tion proceeds slowly, and 5 – 11% of acid reacts in the initial
period of mixing time, comparable with the combined mill
Refractories and Industrial Ceramics Vol. 57, No. 1, May, 2016
1083-4877/16/05701-0042 © 2016 Springer Science+Business Media New York
Proceedings of the International Conference of Refractory
Workers and Metallurgists (19 – 20 March, 2015, Moscow).
FGBOU VPO V. G. Shukhov Belgorod State Technological Uni
versity, Belgorod, Russia.