If you're usually make electronic printed board to yourself using ferric chloride and don't know that you can use it "for ever", then read carefully this page and you'll learn how simply regenerate ferric chloride.
chloride (FeCl3 : Fe=Iron, Cl=Chlorine) is a ferrous basic salt (so you're wrong
when you call it "acid", as you're wrong when calling it
per-chloride); it's a brown liquid (you can find it also in powder form, but i
prefer the liquid one);
It attacks copper (the electronic board) wich became oxidized (take oxygen) while the iron (in the ferric chloride) became reduced (give oxygen).
Work after work, board after board the action-time became more and more long and you'll note muddiness in the tank; solution's acidity will lower;
It's necessary to regenerate it;
first it's necessary to raise the acidity, adding hydrochloridic acid HCl (you'll
find at shop as muriatic acid, mixed with water.....ask mum);
make this work in a open place (DANGEROUS GAS) addig HCl until the muddiness in the tank disappears (or you can also use a litmus paper).
2) Now we can regenerate the solution using same of the oxidator in the following table
|Nitric acid||nitrose oxide|
are going to do is a new reaction, but this time the ferric chloride take oxygen
(became oxidized) and the oxidator give oxygen (became reduced);
Hydrogen peroxide will be the easier to find and more secure.
After a regeneration (if using a water-mixed HCl, as the muriatic acid is) you'll have water in the tank; that's not a problem but you can eliminate it simply putting the tank on a gas-stove and waiting until the water is evaporated.
I use to regenerate my ferric chloride adding only muriatic acid and my solution is working fine from 4 years.
73 de iz7ath, Talino Tribuzio