metalresearcher
National Hazard
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High temperature 'incineration' of smartphones and e-waste ?
A smartphone contains at least half of all 83 natural occurring elements.
Currently most e-waste goes to some African countries or India where people and even children are working with dangerous chemicals without any
protection and all fumes are just dumped into the ambient air.
http://www.compoundchem.com/wp-content/uploads/2014/02/The-C...
I think that high temperature incinerating old smartphones (and e-waste in general) can reclaim the metals.
Putting the e-waste in an electic arc in an inert atmosphere, which temperature is over 3000 C, will result the waste to vaporize, all more complex
compounds like plastics will decompose to simple hydrocarbons and other simple compounds like CO. Most of the metals will vaporize, except the highest
melting ones like W, Ta (the latter from capacitors) and can be condensed in a fractional way which can reclaim the Li of the battery almost in a pure
state due to its relatively low boiling point.
The precious metal remains, which comprise mostly of Cu (wiring) and soms Ag and Au (contacts), can be separated by electrolysis which already happens
with such waste. Only metals like In and Sn (from the touchscreen) and Al (iPhone body) are a bit harder to reclaim I think.
Ceramic materials (glass of the screen, etc) just float as a slag on the metallic remains.
This way can be environmentally friendly, as no noxious gases are generated because these toxic gases are all decomposed at such temperatures.
Can this be a feasible way ?
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NWS
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I would recommend looking at chemical extraction first. The material used in circuit boards can contain chlorine and bromine(see FR-4 https://en.m.wikipedia.org/wiki/FR-4 ) , and there may be other plastics present which could produce under anoxic or reducing conditions some
pretty nasty stuff like dioxins. You won't get CO without a source of oxygen.
[Edited on 6-5-2017 by NWS]
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metalresearcher
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Quote: Originally posted by NWS  | I would recommend looking at chemical extraction first. The material used in circuit boards can contain chlorine and bromine(see FR-4 https://en.m.wikipedia.org/wiki/FR-4 ) , and there may be other plastics present which could produce under anoxic or reducing conditions some
pretty nasty stuff like dioxins. You won't get CO without a source of oxygen.
[Edited on 6-5-2017 by NWS] |
That is exactly what I mean: at such high temperatures as in an electric arc (3000 C) dioxins decompose to harmless compounds. Maybe some HCl/HBr but
that can easily be captured with water.
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macckone
International Hazard
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Incineration at those temperatures is not cost effective.
Which is why chemical extraction methods are used.
Crush it up, float the plastic bits, Dissolve the remaining
bits in acid solution then electrolize it. The crushing and
flotation use almost no energy to speak of. Flotation and
electrolysis is also used to clean up heavy metal contaminated
soil in remediation efforts.
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Texium
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Thread Moved
27-11-2023 at 11:22 |
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