US4325792A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification process
Assignee: Individual
•
Filing: 1981-03-09
•
Granted: 1982-04-20
•
Expires: 2001-03-09
Abstract
Abstract The use of aqueous inorganic carbonates or bicarbonates as the catholyte in the electrolytic purification of chromium plating solutions permits the cell to operate at a high capacity and a high efficiency without adversely affecting the oxidation state of the chromium ions in the solution.
Inventors
- 👤 Daniel J. Vaughan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:04
CPC Classifications
C; C25; C25D; C25D21/00; C25D21/16; C25D21/18; Y; Y10; Y10S; Y10S204/00; Y10S204/13
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
113 words
In the electrolytic purification of an aqueous solution of chromic acid contaminated with dissolved metallic cations by passing electric current through an electrodialysis cell comprising (a) a catholyte compartment containing a cathode and a catholyte and (b) an anolyte compartment containing an anode and an anolyte comprising a contaminated chromic acid solution the anolyte and catholyte compartments being separated by a cation-permeable membrane, the improvement comprising employing as the catholyte an aqueous solution of an inorganic carbonate or bicarbonate which forms carbon dioxide and water on contact with the anolyte, whereby a high-capacity, efficient electrodialytic purification can be carried out without adversely affecting the oxidation state of the chromium ions in the anolyte.
Claim 2
Dependent Claim
113 words
In the electrolytic purification of an aqueous solution of chromic acid contaminated with dissolved metallic cations by passing electric current through an electrodialysis cell comprising (a) a catholyte compartment containing a cathode and a catholyte and (b) an anolyte compartment containing an anode and an anolyte comprising a contaminated chromic acid solution the anolyte and catholyte compartments being separated by a cation-permeable membrane, the improvement comprising employing as the catholyte an aqueous solution of an inorganic carbonate or bicarbonate which forms carbon dioxide and water on contact with the anolyte, whereby a high-capacity, efficient electrodialytic purification can be carried out without adversely affecting the oxidation state of the chromium ions in the anolyte.
Claim 3
Dependent Claim
26 words
The purification according to claim 1 wherein the inorganic carbonate or bicarbonate is an alkali metal carbonate, an alkali metal bicarbonae, ammonium carbonate, or ammonium bicarbonate.
Claim 4
Dependent Claim
24 words
The purification according to claim 2 wherein the inorganic carbonate or bicarbonate is sodium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, or ammonium bicarbonate.
References Cited (Backward Citations)
US3481851A
Cited
US3682796A
Cited
US3761369A
Cited
US3764503A
Cited
US4006067A
Cited
US3909381A
Cited
US4118295A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-04-19 | 1985-10-19 | 1986-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-04-19 | 1989-10-19 | 1990-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-04-19 | 1993-10-19 | 1994-04-20 | $7700.00 | Window Closed / Lapsed |