No registration or passwords; no pop-up ads -- just aloha, fun, & answers.
(as an eBay Partner & Amazon Affiliate earns from qualifying purchases).
Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Advertise
 
Help
Wanted
Current
Q&A's
Site 🔍
Search
pub  Where the
world gathers for metal finishing
Q&As since 1989



-----

Recovery of Silver from old mirrors


Q. My pursuit is to find out if extracting the silver that is used to make mirrors is a worthwhile venture to procure pure silver. Are there services that do this?

Thank you SO much.
Brad

Brad Nichols
Investor - Eugene, Oregon
August 2, 2011



simultaneous replies

A. I found 2 good sources that gave silver thickness for common mirrors. Both were listed in the definitive book "Silver: Economics, Metallurgy, and Use" [on eBay or Amazon or AbeBooks] by Butts and Coxe

One said there was about .15 grams of silver per square foot. At today's silver market of $41.65, this is about $.20 per square foot of silver area.

The other said that the thickness can be varied between .0000012" and .0000079". Therefore, using these figures, the value today would be between $.04 and $.26 per square foot of silver area.

Not much silver and lots of costs. Lots of handling and it is heavy and fragile - Chemical costs - Tanks and other equipment - Waste costs - Fume control - silver purification cells - etc., etc. The simplest and probably the best ways to do it would involve stripping in either nitric acid or Cyanide. I could easily set up a process for it but, I think it would be a loser.

I know of no refinery recovering silver from mirrors and that is usually a good indication that there is no profit in it. Maybe I'm wrong, but I doubt it.

Chris Owen
- Nevada, Missouri, USA


A. Hi Brad

I would be very surprised if the cost of chemicals, plant, disposal of waste and complying with extensive regulations did not greatly exceed the value of any silver recovered.
It may also save you a great deal of frustration to know that many modern mirrors are coated with aluminium rather than silver.

geoff smith
Geoff Smith
Hampshire, England


A. I don't think there is enough silver on mirrors to justify the processing costs even at a $40 per ounce price. It is a very thin layer deposited by either immersion plating with iron powder, or electroless plating. It is usually covered with a thin layer of copper and a paint-like coating.

Lyle Kirman
consultant - Cleveland Heights, Ohio


thumbs down signI didn't think of the paint. The paint would have to be removed first, before going after the silver, and that would really make it an expensive chore. Forget it!

Chris Owen
- Nevada, Missouri, USA


thumbs up signGuys, I appreciate the informed feedback in regards to silver extraction/retrieval for profit. I find this most frustrating as it took me a while to even come up with the idea. It has now been shot down by above articles articulating the difficulties and low/non profit involved.

Martin Cichocki
- Corunna, Michigan, USA
December 6, 2012


A. If you have to worry about the paint, use gasoline to get it off; my grand father owns a glass repair and insulation shop in Michigan when he receives broken mirrors he will remove the silver, he uses gasoline to remove the paint then he melts the silver off of the glass. Good luck.

Russell Rayle
- Belmore, Ohio, USA
March 22, 2013


thumbs down signThanks Russell. Your grandfather may be right, but I think we need to warn the readers that gasoline is NOT a generally accepted solvent because of its extreme flammability and the horrific accidents that can result.

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 27, 2013


thumbs down signGasoline contains 10 percent benzene. Causes cancer. Do not breathe or let it contact skin.

Bill remington
- Grand rapids Michigan
March 22, 2024




Melting a mirror to recover the silver

Q. I have a very large heavy old mirror and I was wondering if a foundry could just melt down the mirror and separate the silver?

Monte Miller
- Pueblo, Colorado
October 31, 2018


A. Hi Monte. Chris Owen is quite knowledgeable on such issues and said that he knew of no such refinery. No one has challenged that in 7 years now, so best of luck but don't hold your breath :-)

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


A. Hi Monte

Silver can dissolve in molten glass:
onlinelibrary.wiley.com/doi/pdf/10.1111/j.1151-2916.1949.tb18957.x
So you stand a good chance of turning a simple problem into a near impossible one.
Why not simply dissolve the silver in nitric acid?

BUT are you certain the coating is silver not aluminium?

geoff smith
Geoff Smith
Hampshire, England


A. Hi Monte. I suspect that a very large heavy old mirror is worth far more than the value of its recovered silver even if the recovery was free and easy, which it's certainly not. People may not get what they're asking, of course, but there are nearly a thousand mirrors on eBay in the $200 to $20,000 range.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


antique mirrors on eBay

A. According to the figures I gave in the old post above, the silver content of one square foot of a silver mirror is between 1.5 cents and 9 cents. That is based on the the present silver spot price of $14.70 per troy ounce,

Chris Owen
- Benton, Arkansas, USA


A. Old mirrors make great aquariums after the silver is removed; that's how I came across this.

Cory English
- San Angelo, Texas, U.S.




(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact  -  Privacy Policy  -  ©1995-2024 finishing.com, Pine Beach, New Jersey, USA  -  about "affil links"