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.
>
>>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!
Copper-saturated ferric chloride is the most excellent weed killer. Just
one spray will make a black dead spot on the lawn, so aim carefully.
Pouring it down the dunny or drain should be an excellent way of
killing any tree roots getting into the pipes.