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topic 57518

Recovery of Silver from mirrors


A discussion started in 2011 but continuing through 2018

August 2, 2011

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


simultaneous August 3, 2011

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" [link is to info about this book at Amazon] 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


August 3, 2011

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


August 4, 2011

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, Ohio


August 6, 2011

thumbsdownI 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


December 6, 2012

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


March 22, 2013

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 27, 2013

thumbsdownThanks 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 results from accidents with it.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey



Melting a mirror to recover the silver

October 31, 2018

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


November 2018

A. Hi Monte. Chris Owen is pretty 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
finishing.com
Pine Beach, New Jersey
Striving to live "Aloha"


November 2, 2018

Hi Monte

Silver can dissolve in molten glass:
https://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



adv.    angel gilding logo

November 2018

A. Hi Monte. I suspect that a very large heavy old mirror is worth more than the value of its recovered silver even if the recovery was free and easy, which it's not. Look around on ebay.

Regards,

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


November 3, 2018

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



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