Dan, Alen and Jack are correct. The recovery of value from PCBs is a high hazard process, probably not suited for an U/G science project. The chips, even old ones, have value. The standard method to recover them is to place the board, chip side up, on a molten solder bath. This allows the technicians to easily remove the chips with tongs (do not want to burn fingers) while breathing the lead fumes, which precipitate throughout the area.

The gold is recovered by oxidizing it (Aqua Regia) and the basic cyanide precipitation.

I worked for a chip recovery operation for a few years… Employee safety was an amazingly difficult task.

------------------------------------------------------------------------------------

Stay healthy and prosper

NEAL LANGERMAN, Ph.D.

ADVANCED CHEMICAL SAFETY, Inc. (Retired)

5340 Caminito Cachorro

SAN DIEGO CA 92105

+1 (619) 990-4908

www.chemical-safety.com

From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Jack Reidy
Sent: Tuesday, February 1, 2022 8:25 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Extracting Gold from Electronics

I do wonder, if the student works for this business, why aren't they trying this through them? Safety aside, it sounds like there are potentially some questions to be asked regarding who owns the materials, whether the student could use school resources for a project benefitting a third party corporation, what permits etc. might be necessary regarding a corporation seeking to process electronics waste for profit, etc.

As for the safety aspect, this sounds like something I would have wanted to do as an undergrad, which is generally not a good sign in terms of safety.

Sincerely,

Jack Reidy (he/him)

Research Safety Specialist, Assistant Chemical Hygiene Officer

Environmental Health & Safety

Stanford University

484 Oak Road, Stanford, CA, 94305

Tel: (650) 497-7614

From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of pzavon**At_Symbol_Here**ROCHESTER.RR.COM
Sent: Tuesday, February 1, 2022 8:10 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Extracting Gold from Electronics

Melissa,

As Daniel noted, there is a full industry involved in recovery of metals from circuit boards and similar items.

I can't tell from your note where your student is located, but some years ago I had an Industrial Hygiene student who was employed by one of the players in the metals recovery industry, Sabin Metals. You might want to refer your student to them (https://www.sabinmetal.com/) or a similar company located more conveniently.

Peter Zavon, CIH
Penfield, NY

PZAVON**At_Symbol_Here**Rochester.rr.com

From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Melissa Anderson
Sent: Monday, January 31, 2022 12:45 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [DCHAS-L] Extracting Gold from Electronics

Hi All,

Just got the question below from a student and wanted to get some additional opinions on the best way to respond. My initial take is

1) This is unlikely to be profitable and would be difficult to execute on a larger scale. They're probably better off recycling the materials.

2) I'm not a big fan of generating hazardous waste just for the novelty of seeing if you can perform a cool reaction. I'm inclined to recommend against even suggesting they do this (supervised) at a small scale for the "educational" benefit. (For reference, this is an introductory chem student, not an upper-division student.)

Here's the question text:

"I work for a small business that sells precision measurement equipment. We recently purchased a portion of another company, and as part of that buyout we received literally tens of thousands of old obsolete computer parts and microchips and the like. They're not really worth anything now (except for being really cool, old electronics), so we're not really having much luck trying to resell them. Here's where the potentially fun part comes in.

A good portion of these parts are coated in gold. I've done a bit of research online, and it looks like there's a process to chemically separate the gold from the rest of the components. The internet is, as usual, a bit contradictory on what process is the best way to go about it. Different sites profess their way is best, and I'm obviously green when it comes to chemistry, so I was wondering what your thoughts were?

https://www.wired.co.uk/article/extract-gold-from-electronics

Here's an article I found after a brief google search kind of outlining a process. I was hoping to give this a shot on a small scale and then maybe attempt something larger if I'm successful. But I need to know... Will following this article get me killed or result in a visit from the FBI??? I think it would be a fun, cool way to do a bit of chemistry and make the business I work for a bit of extra money off of some items that would otherwise just be thrown away, but I obviously want to do it in a safe, proper way

Any advice or insight you have would be greatly appreciated"

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