- Salt-effect distillation
Salt-effect distillation is a method of
extractive distillation in which asalt isdissolved in the mixture of liquids to be distilled. The salt acts as a separating agent by raising therelative volatility of the mixture and by breaking anyazeotrope s that may otherwise form.etup
The salt is fed into the
distillation column at a steady rate by adding it to thereflux stream at the top of the column. It dissolves in the liquid phase, and since it is non-volatile , flows out with the heavier bottoms stream. The bottoms are partially or completelyevaporated to recover the salt for reuse.Usage
Extractive distillation is more costly than ordinary
fractional distillation due to costs associated with the recovery of the separating agent. One advantage of salt-effect distillation over other types of azeotropic distillation is the potential for reduced costs associated with energy usage. In addition, the saltion s have a greater effect on the volatility of the mixture to be distilled than other liquid separating agents. [Citation
last = Smallwood
first = Ian McN.
author-link =
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publication-date =
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year = 2002
title = Solvent Recovery Handbook
edition = Second
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pages = 166-167
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publisher = CRC Press
id =
isbn =0849316022
doi =
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url = http://books.google.com/books?id=GcjME0wiMVsC&pg=PA166&lpg=PA166&dq=%22salt+effect+distillation%22&source=web&ots=2LZD-V50yV&sig=9hJuSASlhr2YnbdijAForfqWCqQ#PPA166,M1
accessdate =2007-11-30 ] Commercial usage of salt-effect distillation includes addingmagnesium nitrate to anaqueous solution ofnitric acid to concentrate it further.Calcium chloride is added toacetone -methanol andwater -isopropanol mixtures in order to facilitate separation. [Citation
last=
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year= 2003
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contribution= Salt-effect distillation
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title= McGraw-Hill Dictionary of Scientific and Technical Terms
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publisher=McGraw-Hill
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url=http://www.answers.com/topic/salt-effect-distillation
accessdate =2007-11-30 ]References
ee also
*
Distillation
*Extractive Distillation
*Azeotrope
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