| Summary: | 碩士 === 國立臺灣大學 === 化學工程學系 === 86 === In this study , fine particles of Al2O3 were produced by using
the microemulsion method under atmospheric pressure and
supercritical carbon dioxide environment .
The stable water-in-oil emulsion were prepared and mixed
with the precipitating agent to form precursors , using normal
heptane as the oil phase under atmospheric pressure and carbon
dioxide as the oil phase under supercritical carbon dioxide ,
aluminum nitrate aqueous solution as the water phase , and
aqueous amonia as the precipitating agent . After a series of
operations , including distillation , washing , and filtration , the dried
precipitates were obtained and calcined at 1100℃ to form
corndum crystal of Al2O3 . Factors that influence the morphology
and size of particles were investigated , including the volume ratio
of water-in-oil , the amount of surfactant , and the concentration of
aluminum nitrate .
The properties of produced alumina powders were analyzed by
the electron microscope , BET surface area analyzer , and X-ray
diffraction spectrometer .The result shows that alumina powder
has mean particle size 1∼6μm , specific surface area 14∼
93m2/g and corundum crystal under atmospheric pressure ; and
has mean particle size smaller then 1μm , specific surface area
43∼125m2/g and corundum crystal under supercritical carbon
dioxide .
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