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Author Topic: What is the Precious Metal content in electronics?  (Read 18023 times)

Offline JackDud

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  Hello, all, I'm a long term listener and lurker, and now I'm pressed with some questions so I thought what better than to turn to the brilliant minds of the Naked Science forum. I'm a first year college student working on my final paper for a 'sustainable cities' course. I am exploring the feasibility of starting an end-of-life (e-waste) recycling facility specific to NYC. I need to do some number crunching, and I for the life of me cannot find satisfying statistics. If anyone knows the concentration or amount of precious metals in any sort of electronics (PCs would be most useful) then please fill me in (with citations and references if possible)! Any other e-waste statistics would be interesting as well. So far, the following link is the best information I could find - newbielink:http://ewasteguide.info/valuable_materials_in_e_waste [nonactive] - but it does not seem academic or satisfying enough (all of the <0.1 stats). I'm not trying to get you guys to do my research as I have already found most of what I need, but it seems that I have hit a brick wall on this particular part. Cheers, thanks for any help!  [O8)](<- I was dying to use that)

MOD EDIT: Hi Jack, I have taken the liberty of slightly modifying the title of your topic to be in the form of a question in line with Forum Policy. Please remember to do this on future topics. Thanks for posting! Geezer
« Last Edit: 04/01/2010 18:56:40 by Geezer »


 

Offline graham.d

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Re: What is the Precious Metal content in electronics?
« Reply #1 on: 10/04/2009 11:02:47 »
Hi Jack. I can tell you that many (probably most) integrated circuits use gold bond-wires to connect the chip to the package pins. The amount of gold used will depend on the number of package pins and the average lengths of the wires, so I can't tell you what this represents as an industry average. The wires typically have a diameter of between 15 and 25 microns and the length somewhere around 3mm to 7mm. The gold is not pure, but an alloy made to give suitable properties so its recyclability may be not straightforward. The microchips themselves are often attached to the base of the package (die attach) using a silver-loaded epoxy to give good electrical and thermal conductivity. In addition the bases of packages themselves are often gold plated. Despite all this the amount of precious metals (gold and silver) used is not very high. If you type in to Google - Integrated circuit gold recycle - there seems to be a lot of hits that maybe helpful.
 

Offline techmind

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Re: What is the Precious Metal content in electronics?
« Reply #2 on: 13/04/2009 22:00:46 »
I can't offer any source of validated statistics, but very often gold is used to coat the contacts in switches and plugs and sockets for reliability. For PCs, the "edge connectors" used for PCI cards for example use gold-plated fingers in the sockets, and the part of the PCB of the card which plugs into the motherboard socket is also gold-plated. Better-quality "VGA" monitor D-plugs have gold-plated pins. The gold plating is quite thin, eg 2.5 / 5 / 10 / 15um progressing from a very cheap to a premium connector (you can find such figures in the connector-manufacturers' data and/or distributors' catologues eg Farnell). You could also look up a PCB-manufacturer's website and they might specify the typical thicknesses of gold plating they might apply (only for connector fingers, test-points etc - a very small fraction of total board area normally). I would guess 5-10um is typical.

Small capacitors contain tantalum which isn't a classic precious metal, but is fairly rare compared to recent demand (in ultraminiature capacitors) and only mined in politically unstable countries, so might be worth recovering...


I would guess that the gold in plated contacts could easily exceed that of gold bond wires inside chips in a finished product, but I don't know for sure and it will depend on the product.

Silver plating is occasionally used, but more for RF applications than consumer electronics. The conductivity is silver is excellent, but silver tarnishes, which can be a bit of a drawback.

I can't think of any uses for platinum in consumer electronics.
« Last Edit: 13/04/2009 22:05:58 by techmind »
 

Offline FuzzyUK

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Re: What is the Precious Metal content in electronics?
« Reply #3 on: 18/04/2009 00:04:30 »
Aluminium foil is used in capacitors.

Beryllium oxide is used in heat sinks for RF power transistors.
 

Offline Dr.IC

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Re: What is the Precious Metal content in electronics?
« Reply #4 on: 22/04/2009 09:55:07 »
even copper and titanium is also used.
 

Offline Andrew K Fletcher

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Re: What is the Precious Metal content in electronics?
« Reply #5 on: 22/04/2009 10:55:22 »
platinum is also used for contact breakers in older electrical equipment
 

Offline Pratik

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Re: What is the Precious Metal content in electronics?
« Reply #6 on: 04/01/2010 14:59:05 »
Hey Jack!!!! i dont knw excatly the composition of pcbs n all but m too working on same project.... i m searching for the % composition of various metals in various components of Motherbard.. So we can help each other out ...Contact me pratik_2203@yahoo.com
 

Offline RD

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Re: What is the Precious Metal content in electronics?
« Reply #7 on: 04/01/2010 16:26:07 »
Don't be a prat Pratik, if you post your email address in a forum you will be plagued by spam,
 (If I were you I'd remove it from your post ASAP, if you must contact Jack send him a personal message).

BTW here is a link to European projects to recycle electronic waste ...
Quote
EU legislation restricting the use of hazardous substances in electrical and electric equipment (Directive 2002/95/EC) and promoting the collection and recycling of such equipment (Directive 2002/96/EC) has been in force since February 2003. The legislation provides for the creation of collection schemes where consumers return their used e-waste free of charge. The objective of these schemes is to increase the recycling and/or re-use of such products.
http://ec.europa.eu/environment/waste/weee/index_en.htm
« Last Edit: 04/01/2010 16:29:55 by RD »
 

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Re: What is the Precious Metal content in electronics?
« Reply #7 on: 04/01/2010 16:26:07 »

 

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