At 08:44 AM 10/12/99 +1000, Tony wrote:
>I've been using Ferric Chloride for years now and it serves my purposes
>well. If you look at the method I use at
>http://www.picnpoke.com/projects/pcb.html, you will find that the
>solution lasts a long time with excellent results. I've been using the
>same batch for years. I don't know if it's recylable, but all I know is,
>when it turns green, it's dead.

You should be able to regenerate the solution electrolytically by using
iron and a copper electrodes. Iron will oxidize from one electrode and
copper will plate out on the other. So the copper electrode is the cathode
and the iron one is the anode.

You could calculate the necessary voltage from the half-cell potentials,
but I don't have a table handy. So I would suggest connecting a ammeter in
series and increasing the driving voltage up from zero until current starts
flowing, then stop. The necessary voltage should only be ~ 1 V.

Too high a voltage and you'll electrolyze the water or hydrochloric acid
present. So stop quick if you see any bubbles on the electrodes, and don't
breathe any funny colored fumes!

================================================================
Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: ral@lcfltd.com
Least Cost Formulations, Ltd.                   URL: http://lcfltd.com/
824 Timberlake Drive                            Tel: 757-467-0954
Virginia Beach, VA 23464-3239                   Fax: 757-467-2947

"Vere scire est per causae scire"
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