USING RECYCLED CERAMICS TO MAKE NEW TRIAXIAL CERAMICS
Marcelo Dal Bó
and Dachamir Hotza
Translated from Novye Ogneupory, No. 6, pp. 54 – 62, June, 2013.
Original article submitted December 15, 2012.
A technology is presented for making a triaxial refractory material with the use of factory wastes as the main
component. Mixture design and response-surface analysis were used to decrease the amount of lab work re
quired by determining the range of formulations of the material that is optimum from the standpoint of obtain
ing the necessary characteristics for the finished product. This approach can also significantly improve the
cost/benefit ratio during the formulation stage and help to better understand the relationships between the pro
duction, microstructure, and properties of refractories. Among the raw materials that were used were wastes
from the production of refractory tiles: coal ash, slag sand, glazing wastes, and a high-alumina refractory that
was crushed in edge runners. The methodology used in the study can help identify the region of the ternary di
agram in which the service requirements established for refractories are satisfied by the characteristics of the
product - characteristics such as linear shrinkage and ultimate flexural strength after firing. The optimized
composition that was found for the triaxial refractory has significantly reduced costs compared to the
refractories currently being used and has helped improve the environment as well.
Keywords: waste recycling, ceramic tiles, refractories, mixture design, triaxial refractory.
Several studies have proposed the use of recycled materi-
als as an alternative approach to ceramics production, the
emphasis here being on their economic advantages and envi
ronmental benefits. Pyrikov et. al recently discussed certain
aspects of the commercial use of refractory materials and
wastes from their production . Manfrdini, et al. studied the
repeat use of ceramic sludge in the production of ceramic
tiles , while Escardino, et al. examined the feasibility of
recycling spent catalyst from FCC (fluidized catalyst crack
ing) units in the petroleum industry to replace kaolin as a raw
material for the production of ceramic frits . Dondi, et al.
recycled PC and TV waste glass to make clay bricks and roof
tiles , and Loryuenyong, et al. investigated how the physi
cal and mechanical properties of clay bricks are affected by
the substitution of recycled glass . Segadäes used phase
diagrams to control the production of ceramics from wastes
. Pereira, et al. made use of ceramic formulations pre
pared with industrial wastes and natural sub-products .
Menezes, et al. optimized the content of wastes in ceramic
tiles by resorting to the statistical design of experimental
mixtures , while Junkes, et al. used phase diagrams to de-
velop a formulation for the production of ceramic tiles from
mineral waste .
Other types of waste products have also been used to de
velop formulations for refractory ceramics. Cheng, et al.
demonstrated the feasibility of using synthetic forsterite to
gether with serpentine wastes . Ribeiro, et al. studied a
technology which employs unidirectional dry pressing to ob
tain specimens of a mullite-based refractory ceramic from
different formulations, including some that use Al-rich in
dustrial sludge as the main or only component . Conejo,
et al. examined the recycling of MgO-C refractories from arc
furnaces and ladle-furnaces , and Arianpour, et al. used
up to 30% recycled refractory aggregates to make new mag
nesia refractories . Valenza, et al. evaluated the mechani
cal properties of sintered wastes used in the production of re
fractory tiles , while Sutcu, et al. used a mixture of clay
and recycled paper to obtain anorthite refractory products
with a thermal conductivity of roughly 0.13 W/(m·K) .
Bragança, et al. investigated the use of mineral coal ashes in
insulating refractory brick .
Statistical tools are widely used to create new ceramic
compositions. When a mixture of raw (or recycled) materials
is being developed, the concept of mixture design can be use
ful for quantitatively evaluating the effect of the correspond
Refractories and Industrial Ceramics Vol. 54, No. 3, September, 2013
1083-4877/13/05403-0243 © 2013 Springer Science+Business Media New York
Materials Science and Engineering Program, Federal University
of Santa Catarina, Florianopólis, Brazil.
Faculty of Chemical Engineering, Federal University of Santa
Catarina (Florianópolis, Brazil).