THE PRODUCTION OF β - SIALON BY CARBOTHERMAL REDUCTION AND NITRIDATION OF KANKARA CLAY
THE PRODUCTION OF β - SIALON BY CARBOTHERMAL REDUCTION AND NITRIDATION OF KANKARA CLAY
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Date
1996-05
Authors
MUHAMMAD, Bello Janbako
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Abstract
The production of (β-sialon - a ceramic material that can be used in
the production of refractory articles for use in the iron and steel
industries, chemical and process industries, non ferrous
metallurgical industries etc, from local1y avai1able rawmaterials
using locally assembled production facility has been attempted, p-
Sialon can be prepared from natural aluminosi1icate raw materials
by carbothermal reduction and nitridation at high temperatures (>
1100°C). To produce β-sialon from locally available aluminosi1icate
raw materials, Kankara clay which is a good local kaolinitic clay
was chosen.
Carbothermal reduction of Kankara kaolinitic clay was therefore
carried out in this study, with Onyeama Coal serving as the carbon
source for the reduction reaction in nitrogen gas atmosphere.
Proximate analysis on the Onyeama Coal has shown that, the coal is
rich in the amount of fixed carbon (85.9 wt.%), less ash content
(5.1 wt.%) and moderate volatile matter (8.91 wt.%).
A local production facility to carry out the carbothermal reaction
has been set up. A reaction chamber from locally available raw
materials was designed and fabricated using investment casting
technique. An existing gas-fired furnace design partially
constructed, was completed, assembled and tested. From the
experimental results, the furnace can be operated up to 1060°C
without incorporating a blower for about seven hours.
The bulk nitrogen analysis of the sialon product formed has shown
that very small concentrations of β-sialon were obtained using the
production facility under the operating conditions achieved.
At nitrogen flowrate of 72.4 ml/s, a peak temperature of 1360°C was
achieved during the first production run which lasted for about 13
hours resulting in about 2.97 wt% (β-sialon.
Similarly for the second production run which lasted for about five
hours at nitrogen flowrate of 143.68 ml/s, a peak temperature of
1260°C was achieved resulting in about 3.32 wt.% β-sialon. During
the third production run which lasted for about four hours at
nitrogen flowrate of 102.23 ml/s. a peak temperature of 1315°C was
achieved resulting in about 3.23 wt.% β-sialon.
Description
A THESIS
Presented to
The Postgraduate School
Ahmadu Bello University, Zaria
By
MUHAMMAD, Bello Janbako
In Partial Fulfillment of
the Requirements for the Degree
Master of Science (Chemical Engineering)
Department of Chemical Engineering
Ahmadu Bello University,
Zaria - NIGERIA
MAY, 1996
Keywords
SIALON,, CARBOTHERMAL,, NITRIDATION,, KANKARA CLAY