METHOD FOR RECYCLING NOBLE METAL FROM ELECTRONIC WASTE MATERIAL AND APPARATUS THEREOF

• US 20130174694A1
• Filed: 10/27/2010
• Published: 07/11/2013
• Est. Priority Date: 10/12/2010
• Status: Active Grant

• Current Assignee: Gem Co., Ltd.
• Original Assignee: Kaihua Xu
• Inventors: Xu, Kaihua
• Granted Patent: US 9,328,398 B2
• Time in Patent Office: Days
• US Class Current: 75/10.13
• CPC Class Codes: B03B 9/061 the refuse being industrial
• CPC Class Codes: C22B 11/025 from manufactured products, e.g. from printed circuit boards, from photographic films, paper, or baths
• CPC Class Codes: C22B 4/04 Heavy metals C22B4/005 takes precedence
• CPC Class Codes: C22B 4/08 Apparatus C22B4/005 takes precedence; electric heating elements H05B
• CPC Class Codes: C22B 7/004 separating two or more metals by melting out (liquation), i.e. heating above the temperature of the lower melting metal component(s); by fractional crystallisation (controlled freezing)
• CPC Class Codes: C22B 7/005 Separation by a physical processing technique only, e.g. by mechanical breaking
• CPC Class Codes: F27D 11/12 with electromagnetic fields acting directly on the material being heated
• CPC Class Codes: F27D 2099/0028 Microwave heating
• CPC Class Codes: Y02P 10/20 Recycling
• CPC Class Codes: Y02W 30/50 Reuse, recycling or recovery technologies
• CPC Class Codes: Y02W 30/52 Mechanical processing of waste for the recovery of materials, e.g. crushing, shredding, separation or disassembly
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling

Abstract

A method for recycling noble metals from electronic waste materials and apparatus thereof. The method comprises the following steps: mechanically breaking up the electronic waste materials; removing rubber and plastic materials by electrostatic separation; removing ferromagnetic metals by magnetic separation; removing residual rubber and plastic materials by microwave pyrolysis; removing low-melting-point metals by indirectly heating using microwave; separating the noble metals from one another in turn from low-melting-point metal to high-melting-point metal for recycle. The apparatus includes a microwave housing. A filtering screen is positioned on the inside wall of the housing horizontally, and vertically-arranged and open-ended heating pipes are positioned over the filtering screen. The method and apparatus can adequately recycle resources in the electronic waste materials.

Claims

1. A method for recycling noble metals from electronic waste materials containing noble metals, comprising the following steps:

(1) taking electronic waste materials containing noble metals, mechanically breaking up and sieving to obtain electronic waste powders containing noble metals;

(2) taking said electronic waste powders containing noble metals, removing rubber and plastic materials by electrostatic separation, collecting noble metal-rich part;

(3) taking said noble metal-rich part, removing ferromagnetic metals by magnetic separation, collecting ferromagnetism-free metal-rich part;

(4) taking and feeding said ferromagnetism-free metal-rich part into heating chamber from feed inlet of microwave reactor, shutting the feed inlet valve and valve that connects the channels, heating to pyrogenation temperature T₁=400˜

600°

C. by microwave, collecting gases generated by pyrolysis at exhaust outlet;

(5) heating to melting temperature T₂=700˜

900°

C. by microwave, melting stannum, lead, antimony and other low-melting-point metals, keeping melting for 5˜

30 minutes, allowing the melted low-melting-point metal liquor to pass through the filtering screen, collecting filtrate A and residues A separately;

(6) continue to heat said residues A to melting temperature T₃=990˜

1020°

C. by microwave, melting metal silver, keeping melting for 5˜

30 minutes, allowing melted silver liquor to pass through the filtering screen, collecting filtrate B and residues B separately;

(7) taking said residues B, applying one or more methods of microwave-melting, acid-liquor filtration, electrolysis and extraction to separate one or more noble metals individually.

2. The method as claimed in claim 1, wherein, said step (5) comprises:

heating to melting temperature T₂=700˜

900°

C. by microwave, melting stannum, lead, antimony and other low-melting-point metals, keeping melting for 5˜

30 minutes, opening vacuum pump, vacuum filtrating at 0.2˜

0.5 atmosphere, allowing low-melting-point metals to pass through filtering screen, collecting filtrate and residues separately.

3. The method as claimed in claim 1, wherein, said step (6) comprises:

heating to melting temperature T₃=990˜

1020°

C. by microwave, melting metal silver, keeping melting for 5˜

30 minutes, opening vacuum pump, vacuum filtrating at 0.2˜

0.5 atmosphere, allowing melted silver liquor to pass through filtering screen, collecting filtrate B and residues B separately.

4. The method as claimed in claim 1, wherein, microwave-melting method is applied in said step (7):

taking residues B, heating to melting temperature T₄=1070˜

1075°

C. by microwave, melting metal gold, keeping melting for 5˜

30 minutes, allowing melted gold liquor to pass through the filtering screen, collecting filtrate C and residues C separately;

taking residues C, heating to melting temperature T₅=1480˜

1520°

C. by microwave, allowing melted copper liquor to pass through the filtering screen, keeping melting for 5˜

30 minutes, filtrating, collecting filtrate D and residues D separately;

taking residues D, heating to melting temperature T₆=1580˜

1750°

C. by microwave, melting metal palladium, keeping melting for 5˜

30 minutes, allowing melted palladium liquor to pass through the filtering screen, collecting filtrate E and residues E separately;

taking residues E, heating to melting temperature T₇=1800˜

1900°

C. by microwave, melting metal platinum, keeping melting for 5˜

30 minutes, allowing melted platinum liquor to pass through the filtering screen, collecting filtrate F and residues F separately.

5. The method as claimed in claim 1, wherein, acid-liquor filtration method and microwave-melting method are applied in said step (7):

taking residues B, adding a strong acid like hydrochloric acid, nitric acid, sulfuric acid and other normal strong acids, dissolving the whole metal copper and its oxidants, its chlorides and others in acid liquor and passing through the filtering screen to form filtrate G and residues G;

taking residues G, heating to melting temperature T₈=1070˜

1075°

C. by microwave, melting metal gold, keeping melting for 5˜

30 minutes, allowing melted gold liquor to pass through the filtering screen, collecting filtrate H and residues H separately;

taking residues H, heating to melting temperature T₉=1580˜

1750°

C. by microwave, melting metal palladium, keeping melting for 5˜

30 minutes, allowing melted palladium liquor to pass through the filtering screen, collecting filtrate I and residues I separately;

taking residues I, heating to melting temperature T₁₀=1800˜

1900°

C. by microwave, melting metal platinum, keeping melting for 5˜

30 minutes, allowing melted platinum liquor to pass through the filtering screen, collecting filtrate J and residues J separately.

6. The method as claimed in claim 1, wherein, said step (7) acid-liquor filtration method and either electrolysis or extraction are applied in said step (7):

taking residues B, adding a strong acid like hydrochloric acid, nitric acid, sulfuric acid and other normal strong acid to submerge the residues, dissolving the whole metal copper and its oxidants, its chlorides and others in acid liquor and passing through the filtering screen to form filtrate G and residues G;

separating the residues G by electrolysis or extraction, collecting metal gold, palladium and platinum separately.

7. The method as claimed in claim 4, wherein, said filtration in said step (7) is vacuum filtration.

11. The method as claimed in claim 5, wherein, said filtration in said step (7) is vacuum filtration.

12. The method as claimed in claim 6, wherein, said filtration in said step (7) is vacuum filtration.

8. An apparatus for recycling noble metals from electronic waste materials containing noble metals, comprising:

microwave housing, microwave transmitter positioned on the inside wall of microwave housing, a feed inlet positioned inside said microwave housing for feeding, a microwave chamber formed in said hollow microwave housing, wherein,

a filtering screen positioned on the inside wall of the housing horizontally,

one or more heating pipes used to heat electronic waste powders containing noble metals positioned over said filtering screen, said heating pipes whose internal spaces are heating chambers provided for electronic waste powders containing noble metals to pass by and to be placed in are vertically-arranged and open-ended,

temperature detector positioned over heating pipes, which is used to detect the temperature of heating pipes,

exhaust outlet positioned over said microwave housing, which is used to get rid of gases generated by pyrolysis,

and sub-pipeline positioned at the bottom of said microwave housing, which is used to discharge materials.

9. The apparatus as claimed in claim 8, wherein, height of said heating pipes is in the range of 10˜

100 cm, pipe diameter is in the range of 3˜

10 cm.

10. The apparatus as claimed in claim 8, wherein, further comprises:

vacuum housing that connects to the sub-pipeline positioned at the bottom of microwave housing, vacuum pump positioned over said vacuum housing, and feed outlet positioned at the bottom of said vacuum housing, vacuum chamber formed in said hollow vacuum housing.