[labnetwork] Disposal of used silicon wafers

[Yakimov, Michael]

As a wild guess... Once you have any metal deposition on any of those wafers - they cannot really be re-melted as semiconductor-grade silicon. Repolishing may be OK, although I suspect final cleaning would still be pricy if anything like Fe, Au or Cu was there.   Maybe they can be used as ferrosilicon for steel alloying, if anyone would bother with that for a $2/kg commodity.
I was told that locally taped cardboard boxes with sharp objects, like broken glass or Silicon, can be disposed as regular landfill trash - as long as nothing falls out easily. (your local regulations may vary)

Thanks

Mike

_______________________________________________
Michael Yakimov
Research scientist
Department  of Nanoscale Science and Engineering
University at Albany - State University of NY

253 Fuller rd.
Albany NY 12203

Phone: 518-437-8609 lab
e-mail: myakimov at albany.edu<mailto:myakimov at albany.edu>





From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of vsoares at inesc-mn.pt
Sent: Friday, November 14, 2025 8:58
To: 'Lab Network' <labnetwork at mtl.mit.edu>
Subject: [labnetwork] Disposal of used silicon wafers

Dear all,

We are a small lab and through the years have accumulated hundreds of used silicon wafers and would like to dispose of them.
I considered having them recycled but we would need a thousand minimum. The ideal for us would be to send them to a company that can remelt the silicon into ingots, but I only found a company in the US and we are in Europe.
Also, there are not many semiconductor labs in Portugal so I am having trouble finding options.
What do you do with your used wafers?

Thank you in advance,

Virginia Soares

Melhores Cumprimentos/ Best Regards

Virginia Soares

[cid:image001.png at 01DC57B2.E3E25B50]INESC-MN
Rua Alves Redol,9
1000-029 LISBON
PORTUGAL
Tel: +3513100237
https://inesc-mn.pt

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