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Evaporative crystallization of anhydrous sodium carbonate at atmospheric conditions
Author(s) -
Oosterhof Harald,
Witkamp GeertJan,
van Rosmalen Gerda M.
Publication year - 2001
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690471009
Subject(s) - anhydrous , crystallization , boiling , sodium carbonate , ethylene glycol , chemistry , boiling point , solvent , sodium sulfate , water of crystallization , sodium , inorganic chemistry , organic chemistry
Abstract A new process for the production of superdense anhydrous soda ash uses a mixture of water and a high‐boiling second solvent to lower the transition point at which anhydrous (Na 2 CO 3 ) and monohydrous sodium (Na 2 CO 3 ·H 2 O) carbonate are in equilibrium to below the atmospheric boiling point. The stable conditions for anhydrate were first established by measuring the water activity in saturated mixtures of water and ethylene glycol. With the results, fed‐batch evaporative crystallization experiments were carried out. Both the water activity and the crystallization measurements showed that anhydrous soda was stable in boiling mixtures containing more than 22.5 wt. % ethylene glycol (on a salt‐free basis). A subsequent continuous evaporative crystallization experiment produced anhydrous soda ash with a bulk density of 1,550 kg/m 3 , which is substantially higher than that of any other atmospherically crystallized soda.