The EPA only allow a few ppm limit of copper discharged. But
since we are not operating an industrial plant the total copper
we put down the drain might be anywhere from 10 to 100 grams once
a year or so.
You can remove copper with scrap aluminum to almost few ppm
levels. Take a plastic bucket with a lid (common white
polyethylene pale). Pour in spent etchant no more than 1/2 full.
Through in about 100g of scrap aluminium per liter of etchant.
Preferably the aluminium should have high surface area, like
sheets or shim. Solid aluminium blocks take too long to react.
Wait for 1 to 2 weeks.
Solution should be crystal clear with copper metal and aluminium
metal sludge at the bottom.
Syphon off liquid leaving brown sludge (liquid can go in second
bucket for neutralization with lime or direct into state sewage
system). Remove any solid pieces of aluminium that hadn't
completely corrode away. Neutralize sludge with excess lime, put
in sealed bag and dump in land fill.
Stefan Trethan wrote:
> well, neutralizing with develpoer will remove the etching behavoir....
>
> BUT the copper (which is a heavy metal i think, potentially dangerous to
> environment) is still in there.
>
> I have no idea how much it is, or if it is poisonous (or if there is more
> washed off big copper roofs).
>
> I read about "regenerating" machines using steel wool, about electrolysis
> for getting the copper out.
> (not sure if electroplating will work with fe3cl)
> I also read about "mix it with cement after nautralization and dump the
> concrete".
>
>
> You see - i don't really know.
>
> But other thoughts...
> I read that Fe3Cl is actually used by sewage cleaning facilities to help to
> clean
> the sewage water (sure no copper contamination here).
> Also often as a positive property of fe3cl "not too bad to environment" is
> listed...
>
> Most likely such things are not legal to dump in the drain.
> But often this is hard to find out (because homebrew pcb making isn't
> popular...).
> If possible without "alerting" the authorities check with your local
> laws...
>
>
> Where I live such "dangerous" waste can be brought to local collection
> facilities.
> But i fear in my village the guys from the responsible facility wouldn't
> know what to do either...
>
> maybe after neutralization it will just work to let the water evaporize and
> then dump the residue.
>
>
> I changed to Hcl H2O2 process. there is no waste. that's good.
>
> I think i told you everything i know about this, hope you find a chemist
> with more precise information.
>
> You know - there is this saying among chem. engineers: "the solution to
> pollution is dilution" ;-)
>
> Stefan
>
>
>
>
>
> On Thu, 16 Oct 2003 15:43:30 -0000, mr_gees100_peas <geovar13@...>
> wrote:
>
>
>>I'm new at this and I want to do my first pcb. I have a cad software,
>>copper board, ferric chloride, drills, ect, ect. By doing a lot of
>>reading I think I have a god idea on how to do it. However, of all the
>>webpages and articles I found on how to make a pcb non of them talk about
>>what to do with the left over feric chloride. I don't think my sewage
>>piping would like me dumping the stuff down the toilet and neither would
>>the enviromentalist. So, my question is, what am I suposed to do with the
>>feric chloride once I make my first pcb? Do I have to take it to a
>>collectionn falicility? Is there a way to neutralise it so I can dump it
>>in the drain and is so, is this legal or good to do?
>>
>>
>>
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>>
>
>
>
>
>
>
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