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Ferric Chloride

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Njubster

Wed Dec 26 2012, 10:31AM

Registered Member #6857 Joined: Sat Sept 22 2012, 08:25AM
Location: Srbija, Novi Sad
Posts: 40

I have few questions regarding it's usage, lifetime, toxicity and disposal. I am not interested in chemistry part, only the practical part, so I hope this thread is still on the right place.

So, I read somewhere that when copper is dissolved in FeCl3, when the etching process is completed what remains is FeCl2 + CuCl2 + some more FeCl3. Does FeCl2 works like FeCl3? Will it etch my boards? I used my solution multiple times, how long will it work?

I used gloves when working with it. Is that enough? Are there any toxic vapors? How toxic is it exactly? Will it burn my skin or something? Just curious about this part.

I have a plastic box full of it on my balcony, and now it's colored like copper after several uses. I noticed it does not work as fast as it used to work, and I'd like to get rid of it somehow without damaging the plums, nature or anything. What's the safest way to do that? I live in a building in a crowded town.

PS: Sorry for my bad English and thanks in advance

Josh Campbell

Wed Dec 26 2012, 08:35PM

Registered Member #5258 Joined: Sun Jun 10 2012, 10:15PM
Location: Missouri - USA
Posts: 119

As far as safety goes use glove and avoid prolonged skin contact or breathing vapors and you'll be ok. It is not a carcinogen, the most damage FeCl3 can do is a mild skin burn or raising iron levels in your blood if you had prolonged regular contact with it. Drinking it, especially after it has copper salts in it would be a bad idea.

Unused FeCl3 can be pored down the drain (once diluted) since the ferric has no serious environmental impact. However once it has been used to etch copper, the cupric chloride (copper salts) are extremely poisonous to fish and other aquatic life even in very small amounts. Used FeCl3 must be taken to a hazardous waste disposal facility.

FeCl3 lasts a long time, but as it becomes saturated it's effectiveness drops. You can simply add more FeCl3 to the used solution to keep it from becoming saturated if your tank is large enough. There are some reclamation ideas out there (some involving electrolysis which causes the copper to accumulate on the cathode) although I never considered them cost/time effective and have never used them.

I heat mine before use and use a ventilation fan to outdoors since the vapors are rather noxious (breath hot FeCl3 vapors once and you'll never do it again).

Material Safety Data Sheet - Ferric Chloride

There is also the H2O2/HCl option which is quite simple and low cost. I prefer FeCl3 though.

Njubster

Fri Jan 04 2013, 10:00PM

Registered Member #6857 Joined: Sat Sept 22 2012, 08:25AM
Location: Srbija, Novi Sad
Posts: 40

Thanks for your reply. Now I'm relieved, I was afraid I gave cancer to everyone in my house or something :D

But I wasn't able to find any info of such a facility in my town, and "cleaner's" website (don't know the word) has no information about disposing such things.

Could I just spill it in some hole in the ground and bury it?

Ash Small

Sat Jan 05 2013, 02:36PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Njubster wrote ...

Could I just spill it in some hole in the ground and bury it?

I'd try electrolysis first to remove the copper salts, then dilute it, and pour it down the sink.

Just 'dumping it' will poison the ground, and may seep into the water table.

You should be able to find information on electrolysis fairly easily.

ConKbot of Doom

Sat Jan 05 2013, 07:00PM

Registered Member #509 Joined: Sat Feb 10 2007, 07:02AM
Location:
Posts: 329

Baking soda can make it foam up, neutralize, you can add water, let it settle, pour off the liquid down the drain, and the left over sludge contains the copper salts, which you can let dry out and store for disposal later. A 5 gallon bucket should be able to hold your dried out residue for quite a while, so you can make trips to a hazmat disposal place every decade or so :p

Disposing of it in the trash would be better then dumping it, as a landfill should have the water situation better controlled, but still not ideal.

Avalanche

Sat Jan 05 2013, 09:34PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

I've often noticed that if you leave used ferric chloride to settle, the 'brown stuff' will sink to the bottom, and the 'water' on top is green (i.e. copper) coloured. As I have almost no clue when it comes to chemistry, is the 'brown stuff' ferric chloride, and should I use it to mix up a new batch of ferric chloride?

As for disposing of the used stuff, just pour it down the sink, or chuck it outside - whatever makes you feel better. It's not even a drop in the ocean, and it will become dissolved anyway whatever you do

There's nothing to worry about!

Bored Chemist

Sun Jan 06 2013, 01:54PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

Avalanche wrote ...

is the 'brown stuff' ferric chloride, and should I use it to mix up a new batch of ferric chloride?

No.
It's mainly ferric hydroxide, and it wouldn't work.

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