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US3843504A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of continuously regenerating and recycling a spent etching solution

Assignee: AT&T Inc
•
Filing: 1972-08-16
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Granted: 1974-10-22
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Expires: 1992-08-16
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Abstract

Abstract 1. A METHOD OF REDUCING A METAL SULFATE TO ITS CORRESPONDING METAL WHEREIN THE METAL SULFATE IS SELECTED FROM THE GROUP CONSISTING OF COPPER SULFATE, COBALT SULFATE, IRON SULFATE, NICKEL SULFATE AND ZINC SULFATE AND IS IN A SOLUTION COMPRISING SODIUM PERSULFATE AND POTASSIUM SULFATE IN A MOLAR CONCENTRATION IN EXCESS OF THE PERSULFATE CONCENTRATION, COMPRISING THE STEPS OF: COOLING THE SOLUTION TO A TEMPERATURE BELOW ABOUT 20* TO PRECIPITATE POTASSIUM PERSULFATE, THEREBY FORMING A SOLUTION ESSENTIALLY FREE OF PERSULFATE VALUES; AND EXPOSING THE ESSENTIALLY PERSULFATE FREE SOLUTION TO AN ELECTROLYTIC REACTION TO REDUCE THE METAL IN THE METAL SULFATE TO ITS CORRESPONDING METAL.

Inventors

  • 👤 B Nayder

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 09:30
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/46

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 103 words
A METHOD OF REDUCING A METAL SULFATE TO ITS CORRESPONDING METAL WHEREIN THE METAL SULFATE IS SELECTED FROM THE GROUP CONSISTING OF COPPER SULFATE, COBALT SULFATE, IRON SULFATE, NICKEL SULFATE AND ZINC SULFATE AND IS IN A SOLUTION COMPRISING SODIUM PERSULFATE AND POTASSIUM SULFATE IN A MOLAR CONCENTRATION IN EXCESS OF THE PERSULFATE CONCENTRATION, COMPRISING THE STEPS OF: COOLING THE SOLUTION TO A TEMPERATURE BELOW ABOUT 20* TO PRECIPITATE POTASSIUM PERSULFATE, THEREBY FORMING A SOLUTION ESSENTIALLY FREE OF PERSULFATE VALUES; AND EXPOSING THE ESSENTIALLY PERSULFATE FREE SOLUTION TO AN ELECTROLYTIC REACTION TO REDUCE THE METAL IN THE METAL SULFATE TO ITS CORRESPONDING METAL.
Claim 2
Independent Claim 103 words
A METHOD OF REDUCING A METAL SULFATE TO ITS CORRESPONDING METAL WHEREIN THE METAL SULFATE IS SELECTED FROM THE GROUP CONSISTING OF COPPER SULFATE, COBALT SULFATE, IRON SULFATE, NICKEL SULFATE AND ZINC SULFATE AND IS IN A SOLUTION COMPRISING SODIUM PERSULFATE AND POTASSIUM SULFATE IN A MOLAR CONCENTRATION IN EXCESS OF THE PERSULFATE CONCENTRATION, COMPRISING THE STEPS OF: COOLING THE SOLUTION TO A TEMPERATURE BELOW ABOUT 20* TO PRECIPITATE POTASSIUM PERSULFATE, THEREBY FORMING A SOLUTION ESSENTIALLY FREE OF PERSULFATE VALUES; AND EXPOSING THE ESSENTIALLY PERSULFATE FREE SOLUTION TO AN ELECTROLYTIC REACTION TO REDUCE THE METAL IN THE METAL SULFATE TO ITS CORRESPONDING METAL.

References Cited (Backward Citations)

No citation records indexed.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-10-21 1978-04-22 1978-10-22 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-10-21 1982-04-22 1982-10-22 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-10-21 1986-04-22 1986-10-22 $7700.00 Window Closed / Lapsed

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