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US4461685A
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Method for producing acicular iron or iron alloy particles
Assignee: Olin Corp
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Filing: 1983-05-27
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Granted: 1984-07-24
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Expires: 2003-05-27
Abstract
Abstract A method is disclosed for producing iron or iron alloy particles. A metal or metal alloy strip having fine particles or iron or alloy distributed throughout is provided. The metal strip is selectively dissolved without substantial dissolving of the iron or iron alloy particles in order to recover the particles.
Inventors
- 👤 Michael J. Pryor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:52
CPC Classifications
B; B22; B22F; B22F9/00; B22F9/16; C; C25; C25F; C25F3/00; C25F3/02; C25F5/00; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12014; Y10T428/12028; Y10T428/12181; Y10T428/12465
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
91 words
A method of producing iron or iron alloy particles, comprising the steps of: providing a copper or copper alloy strip having distributed therein fine particles of iron or iron alloy; and selectively dissolving said copper or copper alloy strip without substantial dissolving of said iron or iron alloy particles to recover said particles, said step of dissolving including immersing said metal strip in an electrolytic solution selected from the group consisting of alkaline metal sulfates so that the iron alloy particles are passivated while permitting electrolytic dissolution of the alloy strip.
Claim 2
Independent Claim
91 words
A method of producing iron or iron alloy particles, comprising the steps of: providing a copper or copper alloy strip having distributed therein fine particles of iron or iron alloy; and selectively dissolving said copper or copper alloy strip without substantial dissolving of said iron or iron alloy particles to recover said particles, said step of dissolving including immersing said metal strip in an electrolytic solution selected from the group consisting of alkaline metal sulfates so that the iron alloy particles are passivated while permitting electrolytic dissolution of the alloy strip.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said electrolytic solution is sodium sulfate.
Claim 4
Dependent Claim
19 words
The method of claim 2 wherein the concentration of sodium sulfate is between about 0.05 to about 4.0 normal.
Claim 5
Dependent Claim
76 words
The method of claim 3 further including the steps of: passing any electric current through said electrolytic solution between a counter electrode and a working electrode, said working electrode further being in electrical contact with said strip, maintaining the potential of said copper or copper alloy strip at a substantially constant value between about 0.0 and 1.5 volts SHE ; and depositing said copper on said counter electrode to free the iron or iron alloy particles.
Claim 6
Dependent Claim
19 words
The method of claim 1 wherein said step of dissolving further includes collecting said iron or iron alloy particles.
Claim 7
Dependent Claim
16 words
The method of claim 5 further including the step of preventing corrosion of the collected particles.
Claim 8
Dependent Claim
42 words
The method of claim 6 wherein the step of preventing corrosion includes the step of washing the collected particles in water containing an oxidizing corrosion inhibitor selected from the group consisting essentially of sodium chromate, sodium nitrite, sodium temptate and sodium molybdate.
Claim 9
Dependent Claim
18 words
The method of claim 7 further including the step of rapidly drying said particles after the washing step.
Claim 10
Dependent Claim
20 words
The method of claim 5 wherein the step of preventing corrosion includes deaerating said electrolytic medium with an inert gas.
Claim 11
Dependent Claim
11 words
The method of claim 9 wherein said inert gas is nitrogen.
Claim 12
Dependent Claim
32 words
The method of claim 6 wherein the step of preventing corrosion includes applying a metal coating to the particles having a thickness in the range of about 100 to about 500 microinches.
Claim 13
Dependent Claim
11 words
The method of claim 11 wherein said coating is essentially copper.
Claim 14
Dependent Claim
22 words
The method of claim 15 wherein said fine particles are acicular having an aspect ratio of between about 4:1 to about 15:1.
Claim 15
Dependent Claim
20 words
The method of claim 13 wherein the acicular particles have an aspect ratio of between about 5:1 to about 7:1.
Claim 16
Dependent Claim
23 words
The method of claim 1 further including the step of rolling said strip to elongate said particles prior to selectively dissolving said strip.
Claim 17
Dependent Claim
16 words
As an article of manufacture, a product prepared in accordance with the method of claim 1.
Claim 18
Dependent Claim
16 words
As an article of manufacture, a product prepared in accordance with the method of claim 6.
Claim 19
Dependent Claim
16 words
As an article of manufacture, a product prepared in accordance with the method of claim 11.
Claim 20
Dependent Claim
31 words
The method of claim 15 further including the step of annealing the strip at a temperature in the range of about 400° C. to about 900° C. to soften the particles.
Claim 21
Dependent Claim
37 words
Free acicular iron or iron alloy particles being in the wrought condition and having a length in the range of about 0.05 to about 0.5 microns and an aspect ratio of between about 4:1 and about 15:1.
Claim 22
Dependent Claim
37 words
Free acicular iron or iron alloy particles being in the wrought condition and having a length in the range of about 0.05 to about 0.5 microns and an aspect ratio of between about 4:1 and about 15:1.
Claim 23
Dependent Claim
16 words
The particles of claim 20 wherein said aspect ratio is between about 5:1 to about 7:1.
Claim 24
Dependent Claim
19 words
The particles of claim 20 having a metal coating with a thickness between about 100 to about 500 microinches.
Claim 25
Dependent Claim
19 words
The particles of claim 22 wherein said coating has a thickness of between about 200 to about 300 microinches.
Claim 26
Dependent Claim
12 words
The particles of claim 22 wherein said metal coating is essentially copper.
Claim 27
Dependent Claim
12 words
The particles of claim 22 wherein said metal coating is essentially cobalt.
Claim 28
Dependent Claim
11 words
The particles of claim 11 wherein said coating is essentially cobalt.
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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) | 1987-07-24 | 1988-01-23 | 1988-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-24 | 1992-01-23 | 1992-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-24 | 1996-01-23 | 1996-07-24 | $7700.00 | Window Closed / Lapsed |