Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" <leon.heller@...>
wrote:
>
> ----- Original Message ----- 
> From: "dl5012" <dl5012@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Tuesday, February 07, 2006 8:17 PM
> Subject: [Homebrew_PCBs] Re: Dangerous Chemicals
> 
> 
> > Hi,
> >
> > Glad you rang in on this topic...
> >
> > What is the proper way to dispose of used ferric chloride?  Is there
> > a way to rejuvinate it?  Someone mentioned adding sulfuric acid, but
> > everyone is imprecise about ratios.  Is there a simple way to
> > determine how much life is left in the etching solution?  Is there
> > an inexpensive way to precipitate the copper out of the solution and
> > end up with just ferric chloride?
> 
> Adding H2O2 and a little HCl should convert any cuprous chloride in the 
> solution to cupric chloride, which is an etchant in its own right. Any 
> ferrous chloride would get converted back to the ferric form. I've
tried it 
> and it seems to work.

Me, too.  You can find HCl, as Muratic Acid, in most hardware 
stores.

> > I'm hesitant to use some of the other recipes.  I've used ferric
> > chloride for many years and my main concern was not breathing the
> > chlorine gas that gets released.  Now, that I'm more environmentally
> > aware, I want to know how to dispose of it properly.  An old bottle
> > I had from Radio Shack said to put it down the toilet.  I'm sure
> > that's not a good thing to do these days...
> 
> I just pour it down the bog!

The Ferric Chloride isn't that bad of a problem.  The problem is
that used solution contains soluable Copper compounds, and these
are lethal to most biological organisms.

> Leon 

Dave