John Popelish wrote:
> --- In Homebrew_PCBs@yahoogroups.com, "dl5012" <dl5012@...> wrote:
> (snip)
>
>>What is the proper way to dispose of used ferric chloride?
>
>
> Other carbonate based chemicals can also be used (sodium bicarbonate,
> calcium carbonate or lime, even portland cement). But sodium
> carbonate is very cheap; the liquid residue is just salt and any extra
> washing soda, and sodium carbonate also serves as a developer for many
> kinds of positive resist, so it is handy to have some around.
>
I experimented with difference neutralizing chemicals for copper
chloride etchants (containing > 150g/L of ionized copper!!!). Safest,
cheapest and easiest was neutralizing with lime. See my page:
http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/index.html#Disposal