[dorkbotpdx-blabber] printed circuit board chemistry

[dan p]

So, depends on what you want. You can use the solution (assuming HCl/H2O2
was the etchant) once it is "used up" by copper etching as a source for
plating copper. Not that difficult, a DC wall wart, a few bits of wire, a
bolt and you can start plating (on another metal).

The other way to get the copper out is with sodium hydroxide. This is a
strong base, and will burn you if not treated with respect (as will HCl)

CuCl2 + 2 Na(OH)2 ->Cu(OH)2 + 2 NaCl

The NaOH will neutralize the solution, and the copper hydroxide will
percipicate out. You can then deal with the small amount of Cu(OH)2 driving
off water to form copper metal or the oxide.

I imagine that if you don't want to deal with sodium hydroxide, even baking
soda should raise the pH to the point where the solids will ppt. The
reaction will be essetially the same.

if you heat the hydroxide to >185c you'll end up with a stable copper oxide
(black). That is about as safe to dispose of as any other rock.

Likely lots of bubbling and spurting (think about the vinegar/baking soda
volcanos you used to make, now thing more) work slow, don't dump.

o.k. assuming you don't wish to be disfigured, blinded, etc. Outside.
gloves. eye protection, etc.

blinking LEDs are much less entertaining when you can't see them.

off the cuff, take with grain of salt, don't do this, I wasn't here, I don't
even know you people.

On Wed, Feb 25, 2009 at 10:36 AM, Eric Garner <garnere at gmail.com> wrote:

> the 3 most common etchants are ferric chloride, sodium or ammonium
> persulphate, and HCl/H202, of the three only the HCl/H2O2 is
> theoretically reusable. FeCl and the persulphates i usually tale to
> the household hazardous waste collection sites at the Metro waste
> transfer stations.
>
>
> ---------- Forwarded message ----------
> From: Daniel Johnson <teknotus at gmail.com>
> Date: Wed, Feb 25, 2009 at 10:27 AM
> Subject: Re: [dorkbotpdx-blabber] printed circuit board chemistry
> To: "A discussion list for dorkbot-pdx (portland,  or)"
> <dorkbotpdx-blabber at dorkbot.org>
>
>
> > I think even more than recovering removed copper from solution, most of
> us
> > would just like to know the proper (bonus: cheap+easy) way of
> > disposing/recycling of waste from this process without killing
> > fish/trees/babies.
>
> I just got this back from my friend.
>
> "What I first need to know is what type of solution you are using to
> dissolve the copper. If the chief concern is killing
> fish/trees/babies, then there are probably more chemicals of concern
> than just the copper. I don't think RETRIEVING the copper for reuse is
> hugely practical.  There are simple ways to remove or complex copper
> but I can't help until I have the solution components. If you know the
> NAMES of the solutions, they most likely contain an analyte list
> (ingrediant list) on the back, and it is required to have an
> associated MSDS (Material Safetey Data Sheet) online. "
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>
> --
> --Eric
> _________________________________________
> Eric Garner
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