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

Patent 4504373 Issued on March 12, 1985. Estimated Expiration Date:

May 2, 2003. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Single film, high performance bipolar membrane
Patent #: 4024043
Issued on: 05/17/1977
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Inventors

Application

No. 06/487651 filed on 05/02/1983

US Classes:

204/534, And using bipolar membrane204/538, Water splitting204/631With bipolar membrane

Examiners

Primary: Niebling, John F.
Assistant: Boggs, B. J. Jr.

Attorney, Agent or Firm

International Classes

C25B 1/00 (20060101)
C25B 1/22 (20060101)
C25B 1/16 (20060101)
C25B 1/14 (20060101)
D01F 13/00 (20060101)
B01D 61/42 (20060101)
B01D 61/44 (20060101)
D01F 13/02 (20060101)

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 H2 SO4. When more than about 5 weight percent H2 SO4 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° C.

Other References

Desikan and Aravamuthan, Chemical Abstracts, vol. 50, 6221c (1956)
Richard M. Kramer, "Electrodialytic Concentration of Sulfuric Acid" University Microfilms, Inc., Ann Arbor, Michigan, (1964)
P. S. Desikan et al., Bull. Central Electrochem. Research Institute, Karaikudi 2, No. 2, 50-58 (1955) [C.A. 50, 6221c (1956)]