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الثلاثاء، 5 أغسطس، 2014

The Use of Turbulence Promotors in the Recovery of Copper from Industral Wastewater by Cementation.

Title: The Use of Turbulence Promotors in the Recovery of Copper from Industral Wastewater by Cementation.

Author        : Basma Samy Mitawea Ibrahim
Collection   : M.Sc. Chemical
Abstract:
The present work is concerned with the enhancement of the rate of Cu ++ ions removal from synthetic wastewater by cementation on zinc cylinder in batch agitated vessel using extended perforated baffles as turbulence promoters. The kinetics of the diffusion controlled Cu ++ions cementation was studied under the effect of the following parameters:
1. Initial Cu ++ ion concentration 11. Type of impeller (Flat blade impeller, 45° pitched blade impeller).
iii. Rotational speed.
IV. Temperature.
v. The effect of the presence of drag reducing polymer.
The rate of Cu ++ cementation was expressed in terms of mass transfer coefficient. The study revealed the following results:
1) Effect of rotational speed: The mass transfer coefficient increases with increasing rotational speed.
2) Type of impeller: The mass transfer coefficient of Cu ++ ions cementation in flat turbine agitated vessel is much higher than the mass transfer coefficient of Cu ++ ions cementation in a 45° pitched turbine agitated vessel for the same rpm.
3) Initial copper ions concentration: As the initial concentration of Cu +2 ions increases,
the mass transfer coefficient increases.
4) Effect of temperature: The mass transfer coefficient increases as the temperature Increases.
5) Activation energy calculation revealed a value of 4.05 kcal/mol: This value indicates the diffusion controlled nature of Cu ++ions cementation on zinc cylinder.
6) Correlation of the mass transfer yielded the following correlations:
• For four blade 450 pitched turbine
Sh= 0.01 Re/•06 SC°.33
In the range of:4145 <Rej< 20724, 1333 <Sc< 2027
• For Four blade flat turbine Sh= 0.001 Re/.33 SCO.33
In the range of: 4145 <Rer- 20724, 1333 <Sc< 2027
7) These dimensionless mass transfer equations can be used for the design and operation of extended perforated baffled batch agitated reactors used to conduct liquid solid diffusion controlled reactions.
8) The presence of drag reducing polymer: The addition of drag reducing polymer inhibited the cementation rate dramatically as reduction varied from 7.4 to 42.9 for 450 pitched turbine and varied from 4.6 to 52.2 for flat turbine depending on Reynolds number and polymer concentration.

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