Khater and Zedane
Greener Journal of Physical Sciences Vol. 2 (1), pp. 001-009, January, 2012.
ISSN: 2276-7851 © 2012 Greener Journals
Manuscript Number: GJPS11007
Geopolymerization of Industrial By-Products and Study of Their Stability upon Firing Treatment.
*H.M. Khater and Sayieda R. Zedane
Housing and Building National
Research Centre (HBNRC)
87 El-Tahreer St., Dokki, Giza, P.O. Box 1770 Cairo
*Corresponding Author’s Email: Hkhater4@ yahoo. com
There is a
growing interest in the development of new cementitious
binders which enhance optimal utilization of industrial
by-products such as phosphogypsum, fly as and cement dust.
Among all the industrial by-products, fly ash predominates
as an alternative building material for building
construction activities. Cement kiln dust (CKD) with its
high alkali content in the activation of geopolymer
specimens to create nonconventional cementitious binders was
investigated. Relatively high alkaline content of CKD is
predominant factor preventing its recycling in cement
manufacture. However, it was observed that depending on the
water-soluble alkalis and sulfate compounds, CKD could
provide the necessary environment to activate geopolymer
materials. Phosphogypsum that is rich in sulfate will
enhance geopolymerization process when added in a lower
dose. Materials used in this investigation are fly ash (FA),
phosphogypsum (PG) and cement kiln dust (CKD) calcined.
Phosphogypsum was partially replaced fly ash in the ratio
from 0 up to 50%, while the remaining ratio is for cement
dust. Alkaline activation by 2 % NaOH along with the added
cement dust was studied and the used water to binder ratio
is 0.55. Curing was performed under 100 % relative humidity
at 60oC. Results showed that 10% PG is the optimum ratio for
geopolymer formation and results in best enhancement in
mechanical as well as microstructural characteristics.
Firing treatment for both 10 and 20% PG mixes possess a
lower strength values up to 800oC, while strength exposed to
strength gain up to 1200oC.
Keywords: cement dust, phosphogypsum, Fly ash, alkali, firing.