Title:
METHOD FOR PURIFYING ZINC SULFATE ELECTROLYTIC BATH
Document Type and Number:
Japanese Patent JPS62297484
Kind Code:
A
Abstract:
Monovalent ions, especially chloride, fluoride and thallium, are efficiently removed from ZnSO4 electrolyte by electrodialysis using alternating monovalent anion permselective membranes and cation exchange membranes or monovalent cation permselective membranes. Electrodialysis is carried out under turbulent flow conditions, at up to 60 DEG C, a differential membrane pressure of less than 150 kPa, a current density of 10 to 500 A/m<2>, and a pH of less than 5.5. Where both chloride and fluoride are removed a pH of 3.5 to 5.5 is maintained. Deposition of manganese and zinc on the electrodes is minimized by at least one of a number of means including arranging the membranes such that the end membranes are monovalent anion permselective; selecting a large electrode rinse flow; adding a small amount of soluble antimony and/or cobalt to the rinse flow; and using a cathode made of a material that promotes hydrogen evolution over zinc deposition. The electrode compartments are preferably rinsed with a 0.1 to 1.0 M Na2SO4 solution at pH 0 to 4.
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Inventors:
DONARUDO ERU BOORU
DANIERU EI DEII BOOTENGU
DANIERU EI DEII BOOTENGU
Application Number:
JP9764487A
Publication Date:
December 24, 1987
Filing Date:
April 22, 1987
Export Citation:
Assignee:
COMINCO LTD
International Classes:
C25C1/16; B01D61/44; B01D61/50; B01D61/54; B01D61/58; B01D65/06; C01G9/06; (IPC1-7): B01D13/02; C25C1/16
Attorney, Agent or Firm:
Akihide Sugimura
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