# US 7,461,449 B2 · Apparatus for reclamation of precious metals from circuit board scrap

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- Number: US 7,461,449 B2
- Document ID: US7461449B2
- Status: Granted
- Kind: B2
- Application number: 11/256,846
- Filed: 2005-10-24
- Published: 2006-02-23
- Granted: 2008-12-09
- Earliest claimed: 2003-11-21
- Inventors: Michael K. Fitch
- Web page: https://patentgrep.com/patent/US7461449B2

## CPC

- B03B 9/061: {the refuse being industrial}
- B03C 9/00: Electrostatic separation not provided for in any single one of the other main groups of this subclass
- C22B 3/165: {with organic acids}
- C22B 7/007: {by acid leaching}
- C22B 11/046: {from manufactured products, e.g. from printed circuit boards, from photographic films, paper or baths}
- H05K 3/22: Secondary treatment of printed circuits {(H05K3/1283 takes precedence; embedding circuits in grooves by pressure H05K3/107)}
- H05K 2203/178: Demolishing, e.g. recycling, reverse engineering, destroying for security purposes; Using biodegradable materials
- Y02P 10/20: Recycling
- Y02W 30/82: Recycling of waste of electrical or electronic equipment [WEEE]
- Y10S 241/38: Solid waste disposal
- Y10T 29/4935: Heat exchanger or boiler making
- Y10T 29/49751: Scrap recovering or utilizing
- Y10T 29/49753: Metalworking to consolidate scrap
- Y10T 29/49755: Separating one material from another
- Y10T 29/49757: by burning or heating
- Y10T 29/53274: Means to disassemble electrical device
- B03B: SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03C: MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS (separating isotopes B01D59/00; combinations of magnetic or electrostatic separation with separation of solids by other means B03B, B07B)
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention springs from the discovery that mild acids could be utilized to shear undesired metals away from desired precious metals that have been plated onto circuit board runners or contacts. This shearing action occurs at a high rate when metal scrap segments are immersed in mild acid and excited by application of an electromagnetic field at specific frequencies and power levels. These frequencies and power levels are based on the end metal desired and the metals contained in the scrap and the acid utilized. When mild acid saturated with copper sulfate and loaded with scrap metals is subjected to an electromagnetic field at the appropriate frequency and power levels, copper and nickel molecules are sheared rapidly and absorbed into solution, leaving only the desired metal, such as gold, in a 99.5% pure flake which can be skimmed off the surface of the solution or filtered from the solution. The captured metal flake is then rinsed in water and denatured alcohol, compressed, melted and poured into bars or nuggets for further use or sale.

## Claims

### Claim 1

An installation for the reclamation of precious metals plated onto circuit board runners and contacts comprising:
a) an induction furnace which is modified by adding a heat exchanger, which circulates a non-conductive fluid with an electric motor and pump assembly through a large inductor adjacent to a nest for a removable v shaped leaded glass beaker and then through said heat exchanger;
b) said induction furnace is further modified by adding wave shaping, frequency control and voltage control through a drive control circuit to standard induction furnace controls; and
c) said v shaped leaded glass beaker.

### Claim 2 (depends on 1)

An installation for the reclamation of precious metals plated onto circuit board runners and contacts as defined in claim 1 where said drive control circuit is selected from a group comprised of:
a) a grid drive control circuit and
b) a cathode drive control circuit
whereby said grid drive control circuit requires less power than said cathode drive control circuit, but said cathode drive control circuit generates a more stable, perfect output wave with no distortion or clipping and, although said cathode control drive circuit requires more power than said grid drive control circuit, said cathode drive control circuit significantly reduces shearing process time.