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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif">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.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif">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)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif">Thanks<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif">Mike<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual">_______________________________________________<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual">Michael Yakimov<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual">Research scientist<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual">Department of Nanoscale Science and Engineering<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual">University at Albany - State University of NY<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual">253 Fuller rd.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual">Albany NY 12203<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual">Phone: 518-437-8609 lab<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual">e-mail:
<a href="mailto:myakimov@albany.edu"><span style="color:#467886">myakimov@albany.edu</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;mso-ligatures:standardcontextual"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Aptos",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> labnetwork <labnetwork-bounces@mtl.mit.edu> <b>
On Behalf Of </b>vsoares@inesc-mn.pt<br>
<b>Sent:</b> Friday, November 14, 2025 8:58<br>
<b>To:</b> 'Lab Network' <labnetwork@mtl.mit.edu><br>
<b>Subject:</b> [labnetwork] Disposal of used silicon wafers<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-GB">Dear all</span><span lang="PT">,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PT"><o:p> </o:p></span></p>
<p class="MsoNormal">We are a small lab and through the years have accumulated hundreds of used silicon wafers and would like to dispose of them.<o:p></o:p></p>
<p class="MsoNormal">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.<o:p></o:p></p>
<p class="MsoNormal">Also, there are not many semiconductor labs in Portugal so I am having trouble finding options.<o:p></o:p></p>
<p class="MsoNormal">What do you do with your used wafers?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank you in advance,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Virginia Soares<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT">Melhores Cumprimentos/ Best Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT">Virginia Soares<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT"><img border="0" width="40" height="35" style="width:.4166in;height:.3666in" id="Picture_x0020_1" src="cid:image001.png@01DC57B2.E3E25B50"></span><span lang="PT" style="mso-fareast-language:PT">INESC-MN<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT">Rua Alves Redol,9<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT">1000-029 LISBON<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT">PORTUGAL<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT">Tel: +3513100237<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PT" style="mso-fareast-language:PT"><a href="https://inesc-mn.pt">https://inesc-mn.pt</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PT"><o:p> </o:p></span></p>
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