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US4723993A
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Hydrometallurgical process for producing finely divided spherical low melting temperature metal based powders
Assignee: Osram Sylvania Inc
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Filing: 1987-03-23
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Granted: 1988-02-09
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Expires: 2007-03-23
Abstract
Abstract A process for producing finely divided spherical metal low melting temperatures powders comprises forming an aqueous solution metals, forming a reducible solid material from the solution, reducing the solid to metal powder particles, subjecting the metal particles to a high temperature zone to melt a portion of the metal powder particles and to form droplets and cooling the droplets to form essentially spherical metal particles.
Inventors
- 👤 Nelson E. Kopatz
- 👤 Walter A. Johnson
- 👤 Joseph E. Ritsko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:32
CPC Classifications
B; B22; B22F; B22F1/00; B22F1/06; B22F1/065; Y; Y10; Y10S; Y10S75/00; Y10S75/953
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
131 words
A process comprising: (a) forming an aqueous solution containing metal values of at least one low melting temperature metal, (b) forming a reducible solid metallic material selected from the group consisting of low melting temperature metal salts, oxides and hydroxides mixtures thereof, (c) reducing said material to form metallic powder particles, (d) entraining at least a portion of said powder particle in a carrier gas, (e) feeding said entrained particles and said carrier gas into a high temperature zone and maintaining said particles in said zone for a sufficient time to melt at least about 50% by weight of said particles, and to form droplets therefrom and (f) cooling said droplets to form metal alloy particles having essentially a spherical shape and an average particle size less than about 20 micrometers.
Claim 2
Dependent Claim
131 words
A process comprising: (a) forming an aqueous solution containing metal values of at least one low melting temperature metal, (b) forming a reducible solid metallic material selected from the group consisting of low melting temperature metal salts, oxides and hydroxides mixtures thereof, (c) reducing said material to form metallic powder particles, (d) entraining at least a portion of said powder particle in a carrier gas, (e) feeding said entrained particles and said carrier gas into a high temperature zone and maintaining said particles in said zone for a sufficient time to melt at least about 50% by weight of said particles, and to form droplets therefrom and (f) cooling said droplets to form metal alloy particles having essentially a spherical shape and an average particle size less than about 20 micrometers.
Claim 3
Dependent Claim
15 words
A process according to claim 1 wherein said aqueous solution contains a water soluble acid.
Claim 4
Dependent Claim
21 words
A process according to claim 2 wherein said reducible solid material is formed by evaporation of the water from the solution.
Claim 5
Dependent Claim
32 words
A process according to claim 2 wherein said reducible solid material is formed by adjusting the pH of the solution to form a solid which is separated from the resulting aqueous phase.
Claim 6
Dependent Claim
24 words
A process according to claim 2 wherein said solution contains a mineral acid selected from the group consisting of hydrochloric, sulfuric and nitric acids.
Claim 7
Dependent Claim
13 words
A process according to claim 5 wherein said mineral acid is hydrochloric acid.
Claim 8
Dependent Claim
27 words
A process according to claim 1 wherein said material produced by step (b) is subjected to a particle size reduction step prior to the reduction step (c).
Claim 9
Dependent Claim
27 words
A process according to claim 1 wherein the powder particles from step (c) are subjected to a particle size reduction step prior to the entraining step (d).
Claim 10
Dependent Claim
17 words
A process according to claim 1 wherein said high temperature zone is created by a plasma touch.
Claim 11
Dependent Claim
14 words
A process according to claim 1 wherein said carrier gas is an inert gas.
Claim 12
Dependent Claim
16 words
A process according to claim 1 wherein essentially all of said metallic metal particles are melted.
Claim 13
Dependent Claim
18 words
A process according to claim 1 wherein the low melting temperature spherical metal particles are a tin-lead alloy.
Claim 14
Dependent Claim
39 words
A process according to claim 1 wherein the spherical metal particles are as alloy containing from about 1.5% by weight to about 5.5% of silver, from about 0.5% by weight to about 2% by weight of tin, balance lead.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-08 | 1991-08-10 | 1992-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-08 | 1995-08-10 | 1996-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-08 | 1999-08-10 | 2000-02-09 | $7700.00 | Window Closed / Lapsed |