Electrodialytic water splitting process and apparatus for conversion of alkali metal sulfate values derived from spent rayon spin baths

Abstract

A process and apparatus for converting alkali metal sulfate values, such as sodium or potassium sulfate values in spent rayon spin bath liquors, into alkali metal hydroxide and alkali metal sulfate/sulfuric acid by using two- or three-compartment electrodialytic water splitter cells. The process and apparatus incorporate the features of: (a) feeding a liquid comprising water to the base compartment of an electrodialytic water splitter, (b) feeding a liquid comprising alkali metal sulfate values to the remaining compartments of the electrodialytic water splitter (c) passing current through said electrodialytic water splitter to produce liquid comprising alkali metal sulfate and sulfuric acid in one of the remaining compartments and a liquid comprising alkali metal hydroxide in said base compartment. The liquid fed to the acid compartments of two- and three-compartment cells may contain H.sub.2 SO.sub.4. When more than about 5 weight percent H.sub.2 SO.sub.4 is present in the alkali metal sulfate solution use of a three-compartment water splitter is preferred. Improved results are obtained when the compartments of the two- and three-compartment water splitter are maintained at a temperature of at least 40.degree. C.

Dependencies are inferred from the claim text.