OXIDATION-RESISTANT NANO-REINFORCED PC-REFRACTORIES
OF MODIFIED PHENOLFORMALDEHYDE RESIN.
PART 2. MODIFICATION OF PHENOLFORMALDEHYDE RESINS
WITH SILICON ALKOXIDE SOLS
G. D. Semchenko,
O. N. Borisenko,
V. V. Povshuk,
D. A. Brazhnik,
L. A. Angolenko,
Yu. V. Permyakov,
and O. A. Vasyuk
Translated from Novye Ogneupory, No. 11, pp. 38 – 42, November, 2016.
Original article submitted June 22, 2016.
Coking of phenolformaldehyde resins (PFRs) modified with various silicon-alkoxide sols produced structur
ally varied carbon binders with cavities filled by entrained sols, depending on the structures of the sili
con-alkoxide hydrolysis products. The physicomechanical properties improved if PFRs modified with sili-
con-alkoxide sols were used. Sols with the stoichiometric amount of water hydrolyzed the silicon alkoxide
Keywords: periclase-carbon (PC) refractories, phenolformaldehyde resin (PFR), modification, silicon-
alkoxide sols, resit structure.
Periclase-carbon (PC) refractories are used to construct
most metallurgical units [1, 2]. PC-refractories are currently
produced using phenolformaldehyde resins (PFRs), coking
of which forms a rather compact and strong carbon binder
that gives the material the required operating characteris
Research results showed that the operating characteris
tics could be improved, in particular, strength and density
were increased whereas porosity decreased because the car
bon binders of the PC-refractories were nano-reinforced
[4, 5]. The methods included, among others, modification of
PFRs by organometallic compounds that were precursors to
synthetic nanoparticles . The available modifiers (organo
metallic compounds and sols based on them) and studies of
their effects on the properties of PC-refractories as a function
of the addition method to the charge are of great practical in
terest. Results from studies of the effect of type of organo
metallic sol on the properties and structure of uncalcined
PFR PC-refractories are presented below.
PC-refractories were prepared using sintered periclase as
filler and green SiC as antioxidant. PFR Bakelite FL 9831
was modified with identical amounts of sol No. 1
(ETS-32/80) and sol No. 2 (ETS-32/60) (Table 1). The sols
were prepared via hydrolysis of ethylsilicate ETS-32 with
stoichiometric (sol ETS-32/80) and a greater amount of wa
ter (ETS-32/60) using HNO
as a hydrolysis catalyst. The
hydrolysis occurred according to the reactions [7 – 9]:
O ® SiO
O ® Si(OH)
Figure 1 shows probable incorporation routes into the
coked binder resit structure of colloidal silica formed
through reaction (1) and silicic acid, through reaction (2).
However, the bond strength of polysilicic acid is different
than that of silica because it has a different structure and
probably cannot be fully incorporated into the resit structure
of the coked resin. Therefore, mass losses of PFR modified
with ETS-32/60 were greater than those for resin modified
with ETS-32/80 .
Modification of PFR with >5% sol produced a watery
mass that made the PC-refractory production process un
Refractories and Industrial Ceramics Vol. 57, No. 6, March, 2017
1083-4877/17/05706-0605 © 2017 Springer Science+Business Media New York
Part 1 was published in Novye Ogneupory, No. 9 (2016).
National Technical University Kharkov Polytechnic Institute,
Kharkov National Economic University, Kharkov, Ukraine.