Apparatus and method for stripping solder metals during the recycling of waste electrical and electronic equipment

Patent metadata

Field	Value
Publication number	US-9649712-B2
Application number	US-201514803936-A
Country	US
Kind code	B2
Filing date	Jul 20, 2015
Priority date	Dec 15, 2011
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

Apparatuses and processes for recycling printed wire boards, wherein electronic components, precious metals and base metals may be collected for reuse and recycling. The apparatuses generally include a mechanical solder removal module and/or a thermal module, a chemical solder removal module, and a precious metal leaching module, wherein the modules are attached for continuous passage of the e-waste from module to module.

First claim

What is claimed is:

1. A process for recovering at least one precious metal from printed wire boards (PWB) and/or PWB components, the process comprising,
(a) heating the PWBs in a heating module to soften solder, adhesives, epoxy, and/or glue to remove the PWB components and/or casing from the PWBs;
(b) removing at least a portion of the solder from the PWBs and/or PWB components using a chemical solder removal composition in a chemical solder removal module;
(c) contacting the PWBs and/or PWB components with a leaching composition in a precious metal leaching module to extract at least a portion of the at least one precious metal from the PWBs and/or PWB components into the leaching composition, wherein the at least one precious metal is substantially dissolved or solubilized in the leaching composition;
(d) isolating the leaching composition from the PWBs and/or PWB components;
(e) rinsing the PWBs and/or PWB components in a rinsing module; and
(f) drying the PWBs and/or PWB components in a drying module.

2. The process of claim 1 , further comprising recovering the at least one precious metal from the isolated leaching composition.

3. The process of claim 1 , wherein the precious metal leaching module, the rinsing module and the drying module are in series.

4. The process of claim 1 , wherein the PWBs and/or PWB components moves manually or automatically from the precious metal leaching module to the rinsing module and to the drying module.

5. The process of claim 4 , wherein the PWBs and/or PWB components moves manually or automatically on a conveyer belt, conveying roller or conveying wheel.

6. The process of claim 1 , further comprising crushing the PWBs and/or PWB components in a crushing module prior to contacting in the precious metal leaching module.

7. The process of claim 1 , wherein the isolated leaching composition comprises precious metal ions.

8. The process of claim 2 , wherein the recovery of the at least one precious metal from the isolated leaching composition comprises reducing, electrowinning or electrochemically converting the precious metal ions to precious metal.

9. The process of claim 8 , further comprising precipitating the at least one precious metal after reduction, electrowinning or electrochemical conversion.

10. The process of claim 1 , wherein the isolation comprises filtering and/or centrifuging and/or decanting the leaching composition from the PWBs and/or PWB components.

11. The process of claim 1 , wherein the leaching composition substantially leaches at least one precious metal from the PWBs and/or PWB components.

12. The process of claim 1 , wherein the leaching composition is purified and recycled.

13. The process of claim 1 , wherein the heating module comprises means for moving the PWBs and/or PWB components through a heating mechanism, wherein the means for moving comprise a roller chain, tracks, belts, or link chains.

14. The process of claim 1 , wherein the heating module comprises agitation means for removing the PWB components and/or casing from the PWBs once the solder, adhesives, epoxy, and/or glue is softened, wherein the agitation means are selected from the group consisting of brushes, pressurized gases, pressurized liquids, rakes, sonic energy and laser energy.

15. The process of claim 1 , wherein the PWB components comprises at least one of a transistor, a capacitor, a heat sink, an integrated circuit, a resistor, an integrated switch, and a processor.

16. The process of claim 1 , wherein the leaching composition comprises a salt brine/acid mixture.

17. The process of claim 1 , further comprising inserting the PWBs and/or PWB components into a drum prior to removing at least a portion of the solder from the PWBs and/or PWB components.

18. The process of claim 17 , wherein the drum is agitated such that the chemical solder removal composition flows past the surface of the PWBs and/or PWB components.

19. The process of claim 1 , wherein the rinsing is effectuated by spraying a rinsing composition on the PWBs and/or PWB components, dipping the PWBs and/or PWB components in a volume of the rinsing composition, contacting the PWBs and/or PWB components with a pad or fibrous sorbent applicator element having the rinsing composition absorbed thereon, or contacting the PWBs and/or PWB components with the rinsing composition that is recirculating.

20. The process of claim 19 , wherein the rinsing composition comprises water.

21. The process of claim 1 , wherein the PWBs and/or PWB components are dried using nitrogen gas, isopropanol, regenerative air, hot air, or spin process technology.

22. The process of claim 1 , wherein the chemical solder removal composition selectively removes lead and/or tin-containing solder from the PWBs and/or PWB components relative to precious metals, tantalum-containing metals, and/or base metals that are simultaneously present on said PWBs and/or PWB components.

23. The process of claim 1 , wherein the chemical solder removal composition comprises at least one oxidizing agent.

24. The process of claim 1 , wherein the chemical solder removal composition comprises nitric acid.

25. The process of claim 1 , wherein the heating module comprises a heating mechanism that is maintained at least 1° C. to about 20° C. below the melting point of the solder and/or epoxy.

26. The process of claim 1 , wherein the at least one precious metal comprises a species selected from the group consisting of gold, silver, platinum, palladium, rhodium, iridium, osmium, rhenium, ruthenium and alloys comprising same.

27. The process of claim 1 , wherein the leaching composition comprises at least one oxidizing agent selected from the group consisting of nitric acid, cyclohexylaminosulfonic acid, hydrogen peroxide, potassium peroxymonosulfate, ammonium peroxomonosulfate, ammonium chlorite, ammonium chlorate, ammonium iodate, ammonium perborate, ammonium perchlorate, ammonium periodate, ammonium persulfate, ammonium hypochlorite, sodium persulfate, sodium hypochlorite, potassium iodate, potassium permanganate, potassium persulfate, potassium hypochlorite, tetramethylammonium chlorite, tetramethylammonium chlorate, tetramethylammonium iodate, tetramethylammonium perborate, tetramethylammonium perchlorate, tetramethylammonium periodate, tetramethylammonium persulfate, tetrabutylammonium peroxomonosulfate, peroxomonosulfuric acid, urea hydrogen peroxide, peracetic acid, sodium nitrate, potassium nitrate, ammonium nitrate, sulfuric acid, methanesulfonic acid, ethanesulfonic acid, 2-hydroxyethanesulfonic acid, n-propanesulfonic acid, isopropanesulfonic acid, isobutenesulfonic acid, n-butanesulfonic acid, n-octanesulfonic acid, benzenesulfonic acid, 4-methoxybenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, 4-aminobenzenesulfonic acid, 4-nitrobenzenesulfonic acid, toluenesulfonic acid, hexylbenzenesulfonic acid, heptylbenzenesulfonic acid, octylbenzenesulfonic acid, nonylbenzenesulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tridecylbenzenesulfonic acid, tetradecylbenzene sulfonic acid, hexadecylbenzene sulfonic acid, 3-nitrobenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 2-nitronaphthalenesulfonic acid, 3-nitronaphthalenesulfonic acid, 2,3-dinitrobenzenesulfonic acid, 2,4-dinitrobenzenesulfonic acid, 2,5-dinitrobenzenesulfonic acid, 2,6-dinitrobenzenesulfonic acid, 3,5-dinitrobenzenesulf

Assignees

• Advanced Tech Materials
• Entegris Inc

Inventors

• Chen Tianniu
• Korzenski Michael B
• Jiang Ping

Classifications

• B09B3/70

  Chemical treatment, e.g. pH adjustment or oxidation (involving an extraction step B09B3/80) · CPC title

• B09B3/35

  Shredding, crushing or cutting · CPC title

• B29B17/02 Primary

  Separating plastics from other materials · CPC title

• H05K3/22 Primary

  Secondary treatment of printed circuits {(H05K3/1283 takes precedence; embedding circuits in grooves by pressure H05K3/107)} · CPC title

• C25C1/00 Primary

  Electrolytic production, recovery or refining of metals by electrolysis of solutions (C25C5/00 takes precedence) · CPC title