Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> --- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
> <stefan_trethan@g...> wrote:
> > On Tue, 06 Sep 2005 08:52:20 +0200, Phil <phil1960us@y...> wrote:
> > 
> > > By the way, I just added a new heater to my tank and did 6 pcbs.  I
> > > got 5 minute etches on 1 oz, ds boards (2 at a time) with a not so
> > > fresh solution of AP at 120 F.  not bad at all.
> > 
> > 
> > yea, but still, what do you do with it when the AP is spent?
> > 
> > ST
> 
> Put it in a jar, place jar on hotplate on low and let it evaporate
> down to a pretty blue mass of crystals.  Dump crystals into a storage
> jar and then take it to a household/toxic waste event that happens
> every 3 months or so.  I've only done this once - it takes about 2
> years to fill the storage jar at the rate I'm going.
> 
> To your point that disposal is an issue that should be factored in -
> yes, I agree it's very attractive to never dispose.  If I were doing
> hundreds of board year, I would have a different point of view.  Right
> now, it is still less work for me to properly dispose AP than to
> regenerate CuCl.

Since the blue crystals are mostly Copper Sulfate, another option 
might be to electroplate out the Copper.  Of course, something
will have to be dissolved into the solution to bind to the sulfate
ions, but that can be a metal which isn't as toxic as Copper (Iron?).

I'll leave further discussion of this up to the chemists.

For additional speculation, would it be possible to electroplate
out the Copper from used Ferric Chloride solution (e.g., Copper
Chloride), and replace it with Iron, thus possibly regenerating the
Ferric Chloride?

Dave