Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Process of treating scrap or waste product containing solid...
Reexamination Certificate
1997-09-26
2002-01-29
Mai, Ngoclan (Department: 1742)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Process of treating scrap or waste product containing solid...
C523S457000, C241S079100, C241S152200, C241SDIG014
Reexamination Certificate
active
06342539
ABSTRACT:
PARTIAL WAIVER OF COPYRIGHT PURSUANT TO 1077 O.G. 22(MAR. 20, 1987)
© Copyright, Ray Chapman 1996. All of the material in this patent application is subject to copyright protection under the copyright laws of the United States and of other countries. As of the first effective filing date of the present application, this material is protected as unpublished material.
However, permission to copy this material is hereby granted to the extent that the owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure, as it appears in the United States Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
FIELD OF INVENTION
In general, the present invention relates to an apparatus and process for separating the constituent components of Printed Wiring Assemblies (hereinafter “PWA's”) and Printed Wiring Boards (hereinafter “PWB's”) (i.e., the unpopulated boards and trim scrap from which the unpopulated boards are produced). In particular, the invention relates to a dry, mechanical process and an associated apparatus whereby PWA's or PWB's are successively and repeatedly crushed into a granular mixture of materials, which may be separated into granular forms of non-metallic and metallic constituent components suitable for reclamation, recycling, and reuse.
Docket No.
Patent/Serial No.
Filing Date/Issue Date
Title
3685-002000
08-582,788
01/04/96, Patent No. 5,829,694
Apparatus and systems thate separate
and Isolate previous and
sent to precious metals from
electronic circuit boards
3685-002001
08-582,784
01/04/96
Process for the separation and
Isolation of precious and
semi-precious metals from
electronic circuit
3685-002003
08-582,788
01/04/96
Process that separate and Isolate
precious and semi-precious
metals from electronic
circuit boards
BACKGROUND
Over the past three decades, since the inception of the integrated circuit and the computer, consumer acceptance combined with technological advances has produced an exceptionally strong market for electrical/electronic products that use integrated circuits and computers for the distribution and manipulation of information and data. The integrated circuits are often encapsulated in ceramic packages, mounted on PWB's to form PWA's, and, ultimately, packaged in various electrical or electronic equipment and appliances (i.e., plastic compartments). PWA's have become ubiquitous in such items as personal and business computers, telecommunications equipment, television sets, and other consumer electronic systems. Normal wear-and-tear and the extraordinary rate of technological change in the capabilities PWA's and PWB's have combined to produce a dramatic increase in the amount of obsolete electronic equipment produced in recent years. Despite the fact that much of this unusable or unwanted equipment contains a multitude of hazardous ingredients including copper and lead, much of this equipment is disposed of by simply placing it in private or municipal landfill sites. This approach is problematic for a variety of reasons. For instance, this approach has the potential for leaking toxic materials into the environment (i.e., water table). In addition, this approach unnecessarily dedicates limited landfill capacity. Consequently, consumer, business, and governmental entities are increasingly directed at the ecologically sound disposal of such equipment and have an intensifying interest in recycling the raw materials such equipment contains.
The disposal of PWA's and PWB's, however, involves special problems. Some of the special problems of properly disposing and/or recycling electrical/electronic equipment and appliances relate to the manner in which PWA's and PWB's are manufactured. PWB's are made by laminating two or more layers of fiberglass reinforced epoxy or polyimide resins with copper foil. The laminate is then coated with a metallic material, usually copper, upon which circuits are traced by a variety of imaging and etching techniques. In addition to quality defects that produce unusable PWB's, the process for producing finished, etched PWB's creates up to 20% waste as trim scrap. Because the material from which PWB's are made is a thermoset, the base can not be remelted and reused once it is produced. Similarly, PWA's are produced from PWB's by soldering or otherwise affixing functional components, such as chips having integrated circuits (hereafter “IC's”), connectors and other components to the base. The composition of these components includes such precious metals as Gold, Silver, Palladium and Platinum, which are encapsulated in ceramic or epoxy resins.
Some existing techniques dispose of PWA's and PWB's in the following fashion. PWA's may be stripped of any reusable components. The partially depopulated PWA's are then sent to a smelter where they are pyrolized to burn off volatile constituents and then crushed. The resulting ash is then reduced by melting and the precious and semi-precious metals are recovered through several pyrometallurgical stages. The value of the precious metals is then calculated, after subtracting the cost of the smelting process, and this value is returned to the supplier of the PWA's.
This process has several disadvantages when complete PWA's are sent directly to smelters:
the smelting process is inherently costly in term of energy usage;
the pryolsis process produces air pollutants that must be scrubbed from oven stacks or otherwise converted into carbon dioxide, which is an environmentally unfriendly substance;
the resulting “sludge” from the smelting process is returned to the landfill, which uses up limited landfill capacity and, in some circumstances, may leak into the environment; and
sampling techniques to determine the precious metal content of the PWA's prior to the smelting operation are impractical and unreliable.
Alternatives to the direct smelting of PWA's include techniques that seek to separate various metal constituent components from the non-metallic constituent components of complete electrical/electronic systems. These techniques include mechanical crushing of electrical/electronic units followed by magnetic separation to remove ferrous metals, followed either by sink flotation techniques to remove lighter weight non-metallic or metallic constituent components; or by density separation techniques followed by treatment of the resulting metallic or non-metallic portions with strong acids, bases or toxic cyanide; or by elaborate series of grinding and density separation steps to completely separate such metals as copper from aluminum and nickel. These approaches still require hazardous components such as Cathode Ray Tubes (CRTs), mercury switches, and Polychlorobiphenly containing capacitors, frequent components of electronic assemblies, to be removed manually. In addition, they involve chemical or water treatment that requires careful and costly monitoring of effluents for hazardous ingredients and/or are costly with respect to the value of the reclaimed materials.
SUMMARY
Generally, in preferred embodiments, PWA's, are removed from electrical or electronic systems, either manually or by a gross shredding operation that is performed on the assembled unit after hazardous items, such as CRTs, mercury switches and Polychlorobiphenyl containing capacitors, are removed. Alternatively, PWB's are simply provided to preferred embodiments. Then, PWB's and/or PWA's are successively and continuously crushed to reduce the overall size of the constituent components. The resulting constituent components contain a mixture of metallic and non-metallic base materials and are separated from one another using the specific gravity of the fractions of material produced. This mechanical process of repeated size reduction and separation generally renders PWA's or PWB's into three fractions: (A) a granular form of the metallic c
Burke R. Darryl
Mai Ngoclan
McKool Smith, P.C.
Resource Concepts, Inc.
LandOfFree
Non-metallic constituent components of printed wiring... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Non-metallic constituent components of printed wiring..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Non-metallic constituent components of printed wiring... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2844598