Structural Chemistry & Crystallography Communication

Mechanical Properties and chemical stability of Roof Tiles: a mixture of Cathode-Ray Tube (CRT) waste glass and Allophane material from Bamboutos (Cameroon) fired at different temperatures

The use of Cathode-Ray Tube (CRT) wastes as fluxing
agent in replacement of Feldspar contribute to reduce
the energy necessary to sintering fired ceramic. In this
work, the effect of CRT waste glasses and allophane on
the physic-mechanical properties and chemical stability
has been investigated. Commercial tile and roof are the
vitrified ceramic that are composed of clay, feldspar, and
quartz. The manufacturing of theses ceramic products
requires high temperature sintering at least at 1250°C
that result in high energy costs a great quantity of thermal
energy is consumed in the firing stage. The aim of this
work is to produce ceramic tile with low energy consumption
and that have good physicochemical and mechanical
properties. The raw materials were characterized in terms
of mineralogical and chemical composition. Different
mixtures with various amounts of glass were prepared
and fired in the temperature range of 700–950°C, for 4h.
The influences of waste glass content on the technological
properties (linear shrinkage, water absorption, bulk
density and flexural strength) were determined. Microstructural
analysis of the fired samples was carried out
by X-ray diffraction and SEM. The experimental results
revealed that Raw materials have good fluxing properties
which were improved with firing. Mechanical and physical
tests such as Linear shrinkage, water absorption, open
porosity, bulk density, flexural strength, loss on ignition,
chemical stability and leaching were used to evaluated
the behaviour of ceramic bodies at sintering temperatures
of 700°C, 750°C, 850°C and 950°C respectively. The
results showed that best physico-mechanical properties
were obtained at 850°C with 30% CRT waste glass added
while water absorption drastically reduced from 16 to
7%, porosity fell from 27 to 10.41% and flexural strength
increased from 5.98 to 20.26MPa. This improved behaviour
observed around 850°C can be attributed to better
glassy phase formation.

Author(s):

Paul Nestor DJOMOU DJONGA

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