| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 83 === The purpose of this study is to develop a laboratory scale of
fluidized bed reactor for removing and recovery of cadmium from
wastewater by the theory of crystallization. By measuring
quartz-sands physical characterization and fluidized bed
hydraulic analysis to find out the nature of equipment for the
basis of next crystallization experiment. The target metal of
cadmium is selected due to itshigh toxicity. The studies also
investigate the various operation limit to determine the
optimal conditions for recovery of cadmium carbonate by
crystallization in a fluidized bed reactor. From the experiment
results, in this case of quartz-sands physical experiment and
paper almost similar result could be found. However, because of
the reaction time is so shortthat the physical characterization
of the pellets make no difference. According to hydraulic view,
the principal limit that influences the hydraulic of fluidized
bed characterization is the surface velocity. As the surface
velocity is increased, Reynolds number, expansion ratio, porous
ratio, pressure drop, energy dispersion and the velocity
gradient as increased, surface area as decreased , that results
are same with paper. Nevertheless the height of fixed bed,
particle size of quartz-sands and glass-pears in distributor
have no obvious influence with the hydraulic characterization
of fluidized bed. Finally, the results of crystallize
experiment showed that the optimal operation conditions of
cadmium carbonate including effluent pH operated between 9.0
and 9.5, the treatment loading can be achieved to 5.00 kg-Cd/m2
h, the influent concentration ratio of CT/Cd is from 1.3 to 6.0
mmol/mmol, the hydraulic loading is more than 49.67 m/h, the
fixed bed depth is the more than 60 cm, and quartz-sands size
between 0.2 and 0.4 mm. st effluent quality and crystallize
efficiency.
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