US3907653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for recovering tin salts from a halogen tin plate sludge
Assignee: Pitt Metals and Chemicals Inc
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Filing: 1975-02-06
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Granted: 1975-09-23
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Expires: 1995-02-06
Abstract
Abstract The sludge of a halogen tin plating bath includes both sodium fluostannate and iron ferrocyanide. The sodium fluostannate is dissolved in water and separated from the iron ferrocyanide by filtration. The sodium fluostannate is thereafter reacted with sodium hydroxide to form tin hydroxide and sodium fluoride. The tin hydroxide is thereafter converted to metallic tin by a suitable electrolytic process. The described process includes reacting the tin hydroxide with sodium hydroxide and steam to form sodium stannate which is converted to metallic tin and sodium hyroxide in an electrolytic cell utilizing insoluble anodes. A multi compartment electrodialytic cell having a plurality of insoluble anodes and a soluble tin anode is utilized to split the sodium fluoride salt and transfer the sodium ion to the cathode compartment and the fluoride ion to the anode compartment. Sodium hydroxide is generated in the cathode compartment and hydrofluoric acid is generated in the insoluble anode compartment. The hydrofluoric acid from the insoluble anode compartment is introduced into an anode compartment containing the soluble tin anode. A solution containing a fluostannite complex is recovered from the soluble anode compartment and is recirculated to the plating bath. Where a sodium fluostannite is desired, a portion of the sodium fluoride is introduced into the soluble tin anode compartment. The sodium hydroxide generated in the cathode compartments may be used in the process for reaction with the sodium fluostannate solution and form the tin hydroxide. The iron ferrocyanide is reacted with a portion of the sodium hydroxide generated in the process to obtain sodium ferrocyanide which may also be utilized in the plating bath. With this process the reactants are generated in the process so that the process does not require other compounds.
Inventors
- 👤 Richard E Horn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:22
CPC Classifications
C; C25; C25D; C25D21/00; C25D21/16; C25D21/18; C25B; C25B1/00; C25B1/01
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
122 words
A PROCESS FOR RECOVERING A TIN SALT SUITABLE FOR USE IN A TIN PLATING BATH FROM THE SLUDGE OF A HALOGEN TIN PLATING BATH COMPRISING, OBTAINING A SLUDGE FROM A HALOGEN TIN PLATING BATH THAT CONTAINS SODIUM FLUOSTANNATE, REACTING THE SODIUM FLUOSTANNATE WITH A BASIC SOLUTION AND FORMING TIN HYDROXIDE AND AN ELECTROLYTE SOLUTION CONTAINING FLUORIDE IONS, CONVERTING THE TIN HYDROXIDE TO METALLIC TIN, POSITIONING THE METALLIC TIN AS A SOLUBLE ANODE IN AN ELECTRODIALYTIC CELL, INTRODUCING SAID ELECTROLYTE SOLUTION CONTAINING FLUORIDE IONS INTO THE ELECTRODIALYTIC CELL ANODE COMPARTMENT CONTAINING THE SOLUBLE METALLIC TIN ANODE, PASSING A CURRENT THROUGH THE ELECTRODIALYTIC CELL AND GENERATING A SOLUTION CONTAINING A FLUOSTANNITE COMPLEX ION IN THE ANODE COMPARTMENT CONTAINING THE METALLIC TIN SOLUBLE ANODE, AND
Claim 2
Dependent Claim
122 words
A PROCESS FOR RECOVERING A TIN SALT SUITABLE FOR USE IN A TIN PLATING BATH FROM THE SLUDGE OF A HALOGEN TIN PLATING BATH COMPRISING, OBTAINING A SLUDGE FROM A HALOGEN TIN PLATING BATH THAT CONTAINS SODIUM FLUOSTANNATE, REACTING THE SODIUM FLUOSTANNATE WITH A BASIC SOLUTION AND FORMING TIN HYDROXIDE AND AN ELECTROLYTE SOLUTION CONTAINING FLUORIDE IONS, CONVERTING THE TIN HYDROXIDE TO METALLIC TIN, POSITIONING THE METALLIC TIN AS A SOLUBLE ANODE IN AN ELECTRODIALYTIC CELL, INTRODUCING SAID ELECTROLYTE SOLUTION CONTAINING FLUORIDE IONS INTO THE ELECTRODIALYTIC CELL ANODE COMPARTMENT CONTAINING THE SOLUBLE METALLIC TIN ANODE, PASSING A CURRENT THROUGH THE ELECTRODIALYTIC CELL AND GENERATING A SOLUTION CONTAINING A FLUOSTANNITE COMPLEX ION IN THE ANODE COMPARTMENT CONTAINING THE METALLIC TIN SOLUBLE ANODE, AND
Claim 3
Dependent Claim
31 words
A process for recovering a tin salt as set forth in claim 1 which includes, reacting the sodium fluostannate with sodium hydroxide and forming tin hydroxide and a sodium fluoride solution.
Claim 4
Dependent Claim
55 words
A process for recovering a tin salt as set forth in claim 2 which includes, introducing the sodium fluoride solution into the intermediate compartment of an electrodialytic cell, passing a current through the electrodialytic cell and generating an electrolyte solution containing hydrofluoric acid in the anode compartment of the electrodialytic cell having an insoluble anode.
Claim 5
Dependent Claim
28 words
A process for recovering a tin salt as set forth in claim 1 which includes, generating a sodium hydroxide solution in the cathode compartment of the electrodialytic cell.
Claim 6
Dependent Claim
49 words
A process for recovering a tin salt as set forth in claim 4 which includes, recovering a sodium hydroxide solution from the cathode compartment of the electrodialytic cell, reacting the sodium fluostannate with sodium hydroxide in the sodium hydroxide solution recovered from the cathode compartment of the electrodialytic cell.
Claim 7
Dependent Claim
58 words
A process for recovering a tin salt as set Forth in claim 1 in which, the sludge contains sodium fluostannate and iron ferrocyanide, dissolving the sodium fluostannate in water to form a sodium fluostannate solution, separating the iron ferrocyanide from the sodium fluostannate solution, and reacting the iron ferrocyanide with sodium hydroxide to recover a sodium ferrocyanide solution.
Claim 8
Dependent Claim
26 words
A process for recovering a tin salt as set forth in claim 1 which includes, reacting a tin hydroxide with sodium hydroxide and recovering sodium stannate.
Claim 9
Dependent Claim
26 words
A process for recovering a tin salt as set forth in claim 7 which includes, converting the sodium stannate electrolytically to metallic tin and sodium hydroxide.
Claim 10
Dependent Claim
53 words
A process for recovering a tin salt as set forth in claim 1 which includes, introducing an electrolyte containing sodium ions into the electrodialytic cell anode compartment containing the soluble metallic tin anode, generating a solution containing a sodium fluostannite compound in the anode compartment suitable for use in a tin plating bath.
Claim 11
Dependent Claim
119 words
A process for recovering a tin salt as set forth in claim 1 which includes, a multi compartment electrodialytic cell with a plurality of anode compartments separated from adjacent cathode compartments by an intermediate compartment, at least one of said anode compartments containing a metallic tin soluble anode and the other anode compartments containing insoluble anodes, introducing said electrolyte containing fluoride ions into the intermediate compartments between cathode compartments and anode compartments containing insoluble anodes and generating an electrolyte solution containing hydrofluoric acid, introducing said electrolyte solution containing said hydrofluoric acid into said anode compartment containing said metallic tin soluble anode, generating a solution containing said fluostannite complex ion in the anode compartment containing the metallic tin soluble anode.
Claim 12
Dependent Claim
49 words
A process for recovering a tin salt as set forth in claim 10 which includes, reacting the sodium fluostannate with sodium hydroxide and forming tin hydroxide and a sodium fluoride solution, introducing said sodium fluoride solution into said intermediate compartments between cathode compartments and anode compartments containing insoluble anodes.
Claim 13
Dependent Claim
88 words
A process for recovering a solution containing a fluostannite complex ion from a solution containing a fluostannate complex ion comprising, reacting the solution containing a fluostannate complex ion with a basic solution and forming a tin hydroxide, converting the tin hydroxide to metallic tin, utilizing the metallic tin as a soluble anode in an electrodialytic cell, introducing an electrolyte containing fluoride ions into the electrodialytic cell containing the soluble metallic tin anode, passing a current through the electrodialytic cell and generating a solution containing a fluostannite complex ion.
Claim 14
Dependent Claim
88 words
A process for recovering a solution containing a fluostannite complex ion from a solution containing a fluostannate complex ion comprising, reacting the solution containing a fluostannate complex ion with a basic solution and forming a tin hydroxide, converting the tin hydroxide to metallic tin, utilizing the metallic tin as a soluble anode in an electrodialytic cell, introducing an electrolyte containing fluoride ions into the electrodialytic cell containing the soluble metallic tin anode, passing a current through the electrodialytic cell and generating a solution containing a fluostannite complex ion.
Claim 15
Dependent Claim
49 words
A process for recovering a solution containing a fluostannite complex ion from a material containing sodium fluostannate as set forth in claim 12 in which, said fluostannite complex ion is contained in a compound selected from the group consisting of H4SnF6, H2SnF4 or Na2SnF4 or Na4SnF6 or mixtures thereof.
Claim 16
Dependent Claim
50 words
A process for recovering a tin salt as set forth in claim 1 which includes, converting at least a portion of the electrolyte solution containing fluoride ions into hydrofluoric acid, introducing said electrolyte solution containing said hydrofluoric acid into the electrodialytic cell anode compartment containing the soluble metallic tin anode.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |