Method for recycling of obsolete printed circuit boards

Patent metadata

Field	Value
Publication number	US-9215813-B2
Application number	US-201113641371-A
Country	US
Kind code	B2
Filing date	Apr 15, 2011
Priority date	Apr 15, 2010
Publication date	Dec 15, 2015
Grant date	Dec 15, 2015

Abstract

Processes for recycling printed wire boards using environmentally-friendly compositions, wherein electronic components, precious metals and base metals may be collected for reuse and recycling.

First claim

What is claimed is:

1. A method of recovering at least one precious metal from a printed wire board (PWB) comprising solder and at least one precious metal, said method comprising:
(a) contacting a surface of the PWB with a first composition, wherein the PWB and the first composition are in a first vessel;
(b) agitating said first vessel;
(c) dissolving or solubilizing the solder in the first composition, wherein the first composition selectively removes the solder relative to the at least one precious metal;
(d) removing the first composition from the PWB by rinsing;
(e) drying the PWB;
(f) contacting the PWB with a leaching composition, wherein the PWB and the leaching composition are in a second vessel;
(g) producing agitation in said second vessel;
(h) dissolving or solubilizing the at least one precious metal in the leaching composition;
(i) removing the leaching composition from the PWB by rinsing; and
(j) recovering the at least one precious metal from the leaching composition,
wherein the first composition is substantially devoid of at least one of fluoride salts, ferric salts, titanium (IV) salts, abrasive material, fluoroboric acid, and ferric nitrate.

2. The method of claim 1 , wherein at least one component is attached to a surface of the PWB, and the at least one component is separated from the PWB during dissolution or solubilization in the first composition, wherein said at least one component is selected from the group consisting of transistors, capacitors, heat sinks, integrated circuits, resistors, integrated switches, chips, processors, and combinations thereof.

3. The method of claim 2 , wherein at least one precious metal is removed from the at least one component using the leaching composition.

4. The method of claim 3 , further comprising the step of crushing the PWB component prior to contact with the leaching composition.

5. The method of claim 2 , wherein the at least one component is reusable or recyclable and are separated accordingly.

6. The method of claim 1 , wherein the solder comprises lead, tin or a lead/tin alloy.

7. The method of claim 1 , wherein the first composition comprises at least one oxidizing agent, and at least one passivating agent for passivating precious metals.

8. The method of claim 7 , wherein the at least one oxidizing agent comprises nitric acid, ozone, bubbled air, cyclohexylaminosulfonic acid, hydrogen peroxide, oxone, 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 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, benzene sulfonic acid derivatives, methanesulfonic acid (MSA), ethanesulfonic acid, 2-hydroxyethanesulfonic acid, n-propanesulfonic acid, isopropanesulfonic acid, isobutenesulfonic acid, n-butanesulfonic acid, n-octanesulfonic acid), benzenesulfonic acid, benzenesulfonic acid derivatives (e.g., 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-dinitrobenzenesulfonic acid, 2,4,6-trinitrobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 2-aminonaphthalenesulfonic acid, 3-aminonaphthalenesulfonic acid, 2,3-diaminobenzenesulfonic acid, 2,4-diaminobenzenesulfonic acid, 2,5-diaminobenzenesulfonic acid, 2,6-diaminobenzenesulfonic acid, 3,5-diaminobenzenesulfonic acid, 2,4,6-triaminobenzenesulfonic acid, 3-hydroxybenzenesulfonic acid, 2-hydroxybenzenesulfonic acid, 2-hydroxynaphthalenesulfonic acid, 3-hydroxynaphthalenesulfonic acid, 2,3-dihydroxybenzenesulfonic acid, 2,4-dihydroxybenzenesulfonic acid, 2,5-dihydroxybenzenesulfonic acid, 2,6-dihydroxybenzenesulfonic acid, 3,5-dihydroxybenzenesulfonic acid, 2,3,4-trihydroxybenzenesulfonic acid, 2,3,5-trihydroxybenzenesulfonic acid, 2,3,6-trihydroxybenzenesulfonic acid, 2,4,5-trihydroxybenzenesulfonic acid, 2,4,6-trihydroxybenzenesulfonic acid, 3,4,5-trihydroxybenzenesulfonic acid, 2,3,4,5-tetrahydroxybenzenesulfonic acid, 2,3,4,6-tetrahydroxybenzenesulfonic acid, 2,3,5,6-tetrahydroxybenzenesulfonic acid, 2,4,5,6-tetrahydroxybenzenesulfonic acid, 3-methoxybenzenesulfonic acid, 2-methoxybenzenesulfonic acid, 2,3-dimethoxybenzenesulfonic acid, 2,4-dimethoxybenzenesulfonic acid, 2,5-dimethoxybenzenesulfonic acid, 2,6-dimethoxybenzenesulfonic acid, 3,5-dimethoxybenzenesulfonic acid, 2,4,6-trimethoxybenzenesulfonic acid, and combinations thereof.

9. The method of claim 7 , wherein the at least one oxidizing agent comprises an alkanesulfonic acid selected from the group consisting of methanesulfonic acid, ethanesulfonic acid, 2-hydroxyethanesulfonic acid, n-propanesulfonic acid, isopropanesulfonic acid, isobutenesulfonic acid, n-butanesulfonic acid, and n-octanesulfonic acid.

10. The method of claim 7 , wherein the at least one passivating agent comprises a triazole derivative selected from the group consisting of 1,2,4-triazole, benzotriazole, tolyltriazole, 5-phenyl-benzotriazole, 5-nitro-benzotriazole, 1-amino-1,2,4-triazole, hydroxybenzotriazole, 2-(5-amino-pentyl)-benzotriazole, 1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3-triazole, 3-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, 5-phenylthiol-benzotriazole, halo-benzotriazoles, naphthotriazole, 4-methyl-4H-1,2,4-triazole-3-thiol, and 3-amino-5-mercapto-1,2,4-triazole.

11. The method of claim 7 , wherein the first composition further comprises at least one complexing agent and/or at least one organic solvent.

12. The method of claim 7 , wherein the first composition is substantially devoid of organic solvents including ethylene groups.

13. The method of claim 1 , further comprising dissolving at least one base metal using a second composition that selectively dissolves base metal relative to precious metal.

14. The method of claim 13 , wherein the base metal comprises nickel, copper, or combinations thereof.

15. The method of claim 13 , wherein the second composition comprises at least one oxidizing agent, optionally at least one base metal complexing agent, optionally at least one organic solvent, and optionally at least one passivating agent for passivating precious metals.

16. The method of claim 15 , comprising the at least one base metal complexing agent, wherein the at least one complexing agent comprises a species selected from the group consisting of ammonium chloride, sodium chloride, lithium chloride, potassium chloride, ammonium sulfate, hydrochloric acid, sulfuric acid, and combinations thereof.

17. The method of claim 15 , wh

Assignees

• BROSSEAU André
• Grigorenko Svitlana
• Jiang Ping
• Korzenski Michael B
• Advanced Tech Materials

Inventors

• BROSSEAU André
• Grigorenko Svitlana
• Jiang Ping
• Korzenski Michael B

Classifications

• C22B11/046

  from manufactured products, e.g. from printed circuit boards, from photographic films, paper or baths · CPC title

• H05K3/22 Primary

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

• H05K2203/176

  Removing, replacing or disconnecting component; Easily removable component · CPC title

• Y02W30/54

  Cross-Sectional Technologies · mapped topic

• C22B7/007 Primary

  by acid leaching · CPC title