A process for conversion of alkali metal sulfate such as sodium or potassium sulfate values comprised of spent rayon spin bath liquors Into alkali metal hydroxide and alkali metal sulfate/sulfuric acid by use of two- or three-compartment electrodialytic water splitter cells (120, 220) which comprises (a) feeding a liquid comprising water to the base compartment (B) of a two- or three-compartment cell; (b) feeding liquid comprising at least a portion of alkali metal sulfate values derived from spent rayon spin bath liquors to the acid compartments (A) of the two-compartment cell and to the salt compartments (S) of a three-compartment cell; (c) feeding a liquid comprising another portion of spent rayon spin bath liquors comprised of alkali metal sulfate values to the acid compartments (A) of a three-compartment cell; (d) passing direct current through said cells while maintaining an average temperature in at least the two-compartment cell of at least 40°C; and (e) withdrawing a liquid comprising alkali metal sulfate and sulfuric acid from said acid compartments (A), a liquid comprising alkali metal hydroxide from said base compartments (B) and a liquid comprising a reduced amount of alkali metal sulfate from said salt compartments (S) is disclosed. The liquid feed to the acid compartments (A) of two- and three-compartment cells may contain H : S0 4 . When more than 5 weight percent H 2 SO 4 is present in the alkali metal sulfate solution to be fed to the acid compartment (A), use of three-compartment water splitting is preferred.