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US4049519A Expired / Lapsed US ⏱️ 0.0 years remaining

Carbonate reduction

Assignee: Individual
•
Filing: 1976-10-06
•
Granted: 1977-09-20
•
Expires: 1996-10-06
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Abstract

Abstract Reduction of carbonate concentrations in cyanide-containing electroplating baths and congeneric solutions using an electrolytic cell, equipped with cation permselective membranes, by the selective addition of hydrogen ions whereby the carbonate ions are converted, in sequence, to bicarbonate ions and then to carbonic acid which decomposes to water and carbon dioxide.

Inventors

  • 👤 Walter John Sloan

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 11:00
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/42; B01D61/44; C; C25; C25D; C25D21/00; C25D21/16; B01D2311/00; B01D2311/04; B01D2311/26; B01D2311/2642

Claims Analysis

Total Claims: 15
Claim 1
Independent Claim 202 words
A process for the removal of carbonate ions from solutions, comprising the steps of: 1. providing electrolytic cell having at least three compartments with two cation permselective membranes separating the cell into anodic, cathodic and carbonate removal compartments; 2. adding an acidic solution to the anodic compartment; 3. adding an electrolytically conductive solution to the cathodic compartment of the electrolytic cell; 4. adding the solution containing carbonate ions to the carbonate removal compartment located between the anodic and cathodic compartments of the electrolytic cell; 5. applying energy, as direct electrical current by the use of the anode and the cathode in the electrical cell, to cause hydrogen ions present in the acidic solution to leave the anodic compartment, pass through the adjacent cation permselective membrane, and enter the carbonate removal compartment holding the solution containing carbonate ions, neutralizing any causticity, and converting carbonate ions to bicarbonate ions which, in turn, are converted to carbonic acid which decomposes to water and carbon dioxide; and 6. concomitantly, causing cations, because of the applied electrical potential, to leave the carbonate removal compartment, enter the cathodic compartment by passing through the second cation permselective membrane, and mix, in the cathodic compartment, with the electrolytically conductive solution.
Claim 2
Dependent Claim 202 words
A process for the removal of carbonate ions from solutions, comprising the steps of: 1. providing electrolytic cell having at least three compartments with two cation permselective membranes separating the cell into anodic, cathodic and carbonate removal compartments; 2. adding an acidic solution to the anodic compartment; 3. adding an electrolytically conductive solution to the cathodic compartment of the electrolytic cell; 4. adding the solution containing carbonate ions to the carbonate removal compartment located between the anodic and cathodic compartments of the electrolytic cell; 5. applying energy, as direct electrical current by the use of the anode and the cathode in the electrical cell, to cause hydrogen ions present in the acidic solution to leave the anodic compartment, pass through the adjacent cation permselective membrane, and enter the carbonate removal compartment holding the solution containing carbonate ions, neutralizing any causticity, and converting carbonate ions to bicarbonate ions which, in turn, are converted to carbonic acid which decomposes to water and carbon dioxide; and 6. concomitantly, causing cations, because of the applied electrical potential, to leave the carbonate removal compartment, enter the cathodic compartment by passing through the second cation permselective membrane, and mix, in the cathodic compartment, with the electrolytically conductive solution.
Claim 3
Dependent Claim 26 words
A process for the removal of carbonate ions from solutions according to claim 1, where carbonate ions are removed from cyanide-containing electroplating baths and congeneric solutions.
Claim 4
Dependent Claim 54 words
A process for the removal of carbonate ions from solutions according to claim 1, wherein the electrolytically conductive solution of step (3) comprises an aqueous solution of alkali metal hydroxide, the carbonate solution of step (4) comprises an aqueous solution containing alkali metal carbonate, and the cations of step (6) comprise alkali metal ions.
Claim 5
Dependent Claim 33 words
A process for the removal of carbonate ions from solutions, according to claim 1, in which the solution containing carbonate ions is flowed upwardly through the carbonate removal compartment of the electrolytic cell.
Claim 6
Dependent Claim 34 words
A process for the removal of carbonate ions from solutions, according to claim 1, wherein the solution containing carbonate ions is recycled, as a batch, through the carbonate removal compartment of the electrolytic cell.
Claim 7
Dependent Claim 32 words
A process for the removal of carbonate ions from solutions, according to claim 1, wherein the solution containing carbonate ions is passed once through the carbonate removal compartment of the electrolytic cell.
Claim 8
Dependent Claim 50 words
A process for the removal of carbonate ions from solutions, according to claim 1, wherein the solution containing carbonate ions is added either as increments or continuously to previously processed solution being recycled through the carbonate removal compartment of the electrolytic cell with incremental or continuous withdrawal of processed solution.
Claim 9
Dependent Claim 53 words
A process for the removal of carbonate ions from solutions, according to claim 1, in which causticity is completely removed and the carbonate ions are substantially converted to bicarbonate ions in one or more electrolytic cells prior to the partial conversion of bicarbonate ions to carbonic acid in one or more electrolytic cells.
Claim 10
Dependent Claim 40 words
A process for the removal of carbonate ions from solutions, according to claim 1 wherein the solution containing carbonate ions is a solution obtained by dissolving alkali metal carbonate crystals produced from plating baths and/or concentrated plating wastes or rinses.
Claim 11
Dependent Claim 42 words
A process for the removal of carbonate ions from solutions, according to claim 1, wherein the three compartments are supplemented by additional compartments, separated by permselective membranes, for accomplishing, by electrodialysis, the concentration of dilute solutions containing the ingredients of electroplating baths.
Claim 12
Dependent Claim 36 words
A process for the removal of carbonate ions from solutions, according to claim 1, in which carbonate ions are converted to bicarbonate ions, the metal bicarbonate precipitates, and the solids are removed from the process stream.
Claim 13
Dependent Claim 47 words
A process for the removal of carbonate ions from solutions, according to claim 1, in which carbonate ions are converted to bicarbonate ions, the bicarbonate precipitates as metal bicarbonate which is then dissolved, and the solution is added to the carbonate removal compartment of an electrolytic cell.
Claim 14
Dependent Claim 48 words
A process for the removal of carbonate ions from solutions, according to claim 1, wherein the solution containing carbonate and cyanide ions is replaced with an electrolytically conductive aqueous solution containing ions which are converted to an acid which is a gas or includes a gas on decomposition.
Claim 15
Dependent Claim 43 words
A process for the removal of carbonate ions from solutions, according to claim 1, wherein the solution containing carbonate ions also contains ferrocyanide ions and zinc which, in the absence of sufficient cyanide ions for complex formation, combine to form insoluble zinc ferrocyanide.

References Cited (Backward Citations)

US3344050A Cited
US3896015A Cited
US3761369A Cited
US3901781A Cited
US3968017A Cited
US3964985A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1980-09-19 1981-03-21 1981-09-20 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1984-09-19 1985-03-21 1985-09-20 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1988-09-19 1989-03-21 1989-09-20 $7700.00 Window Closed / Lapsed

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