how do you all dispose of Ferric Chloride?

[MetalGod]

Just wondering what the best way to dispose of Ferric Chloride is - a student friend said Bicarbonate Of Soda would neutralise it.

Anyone?

[Seljer]

I've been wondering the same thing, I've got a bucket full of used etchant under my sink.

though to what I know of highschool chemistry, baking soda neutralises acids so I guess it should work.

[Thomas P.]

Where I live this kind of waste to collected once every half year by the "ökomobil" or you can take it directly to the waste facilities.
Dumping it into the toilet would be illegal (even though you neutralize it)! But that can differ from country to country.

[majormono]

Sure, you can neutralise the hydrolysated Fe-III-Chloride with a base (NaOH, don't forget to check the pH!) but the environmental problem is actually the Copper (which you usually can't analyze at home, limit is 500µg/l here in germany... not very much!). And don't forget that you may theoretically generate toxic chloride gas in the process - one reason why I  use sodium peroxodisulfate.
Best thing: Bring noxious substances clearly marked to a disposal center without messing with them, alternatively the chemistry department of a university may help (if you know someone there ;-).
Appears trivial, but toxic waste (and that's what it is) is nothing to take lightly - your health and good ole mother nature will thank you. 

[MetalGod]

There is no waste collection service in the UK that will pickup chemical waste from your home.  I may look into this further but I think the neutralising of the CF should be enough - it's not like I'm using gallons of the stuff every week.  Just wanted to see how everyone else got rid of this stuff.

As for health reasons - I use a face mask and goggles when dealing with this stuff.  I've breathed this stuff in once and it wasn't a very nice experience (eyes were watering too).

[Horace]

probably best to take it to a waste management agency....or grow some funky crystals http://www.raphnet.net/divers/cristaux/cristaux_en.php .
seriously, this might be a far better alternative to ferric chloride and reuseable http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/index.html

[Mark Hammer]

Baking soda (NOT baking powder) will produce a chemical reaction with ferric chloride that will render the solution relatively harmless to the environment.  It is how I have been disposing of my etchant for decades now.

Note the following, though:

• Like any rapid chemical reaction, heat is produced so you do NOT want to engage in this on a large and rapid scale; a little bit at a time, wait for it to settle down, and then continue with a bit more
• The reaction results in a foam-like substance being produced which dries into something that looks like rust-coloured styrofoam.  The byproducts of the baking-soda/ferric-chloride interaction occupy about 7-10x the volume of the original ingredients.  This means that if you have a tub of etchant, filled to the brim, and you dump a box of baking soda into it, the reaction will overflow the container and cover your counter with ooze within  20 seconds or so.  Keep in mind that the "ooze" is partly de-activated byproduct by also not-yet-deactivated etchant which will stain for life anything it comes into contact with.  So, you will need a large container (or else place small amounts of your main etchant bath in a medium container) to contain the whole mess or else you risk something you will deeply regret.

The thing about the etchant is that it may LOOK completely treated when it isn't.  You may have just a small residual film at the bottom of the container, and when you dump a few tablespoons of soda on it, it starts foaming like crazy.  You will want to keep applying the soda until the rust-coloured mess you have is fairly dry in texture.  Once you have turned it from wet and dangerous into dry and harmless, you can simply pour all those crumbly bits into a garbage bag and set it out with all the other household waste.

Finally, etchant can often be extended for use a bit longer.  If you have a way of safely storing and transferring the stuff to another container, let your bath sit idly for a couple of days (at least) so that all the copper precipitates are sitting like a thick mud at the bottom.  GENTLY pour the still-useful etchant from the top into another container.  Now you can dump your baking soda into the thick stuff to finish using up whatever molecules of ferric chloride are still around. 

[markm]

Before I started etching everything I come in contact with    I used to just dump it into the pot and flush but now, with enclosure etching and circuit boards, I have been saving it in a jar. I think I may try your method Mark, sounds like a good plan.

[R.G.]

Once it's been neutralized by baking soda, you can use the remaining etchant liquid and some additional water to mix up a part of a bad of ready mixed concrete. This sets into a lump that's environmentally benign. Or you can make a garden wall with etchant-bricks.

[petemoore]

  Isn't there some 'precision cut' dremel that could cut traces...better yet LAzer cutting with a precision lazer controller or maybe a lazer template so the whole board can be zapped across but only where the template allows the light to pass will be cut...
  Not to be contrare' and hijack the thread, but all that chemical schtuff seems a little bit 'klunky'...Dirty, alot to do, mess with, and observe about it, adding more chemicals etc....I know some of that stuff ends up as 'drain cleaner', or 'weed killer' when it shouldn't.

[GibsonGM]

Hi Guys,

I used to work as an environmental consultant...all the negative effects of industry on the environment got me out of that!  I did learn that (as majormono said) limits for releases to the environment of substances such as copper are VERY low.  500 micrograms per liter in his case, similar in the US. I think you might approach that level after a few boards. 

What that means is that if you dump this in your yard, and there's a well nearby, you could easily contaminate it.  Or, if someone goes to sell the house, and a guy like me in my former life does some soil or water tests (and it happens more than you might think!), we'd find it.  Then we would dig up something like 50 cubic yards of your yard to dispose of the wasted soil.  If it's in the groundwater, we'd have to pump and treat that, too.  Makes your property worth about nothing afterwards    Very, very expensive, too!

Please keep in mind the acute problems of using etchant (burns, eye & lung damage, etc), but also the chronic, long-term things...I know all you guys take the spent solution somewhere to be properly disposed of.  Mark Hammer's method is great, I highly endorse that level of responsibility   

Like with anything else in the modern world, a little thought goes a long way.  There's no reason to stop etching, just do some thinking ahead of time.

Rock on!

[puretube]

Mark: does that 7-10x volume foam
reduce to normal, after drying up?
(or can you make it smaller, mechanically?)

[petemoore]

  I just had a full glass of fresh, clean-er-ed, filtered tap water....ahhh nothing better than fresh pure water.
   What Mark Hammer described as a way to deal with this...could be news to etchant dumpers.
  I've not used copperless perfboard [nameword?], because I couldn't figure out a good way to connect/mount sockets without the copper pads.
   +8 for perfboard and RTS PCB's...not really that much more time/trouble compared to etching...I can only guess, 'cause I've not etched a board.
  Makes me wonder how much etchant our group has dumped down the toilet in a recent unit of time...not to sound too hostile when referring to those who are hostile to the environment but..accountability by guilt?
 
   

[Peter Snowberg]

I stopped etching my own boards a long time ago. Board houses recycle their etched copper (usually using it to plate additional copper onto boards.

I live very close to Silicon Valley and the environmental damage the electronics industry has caused here is massive.

[Dirk_Hendrik]

Looking on how eager people on this board tend to be on intellectual property I'd say at least the same amount but preferably more attention might be permanenty be directed to this toxic waste issue.

GibsonM makes some very stiking remarks towards the impact of non-responsive disposal of used chemicals and the semi-long term effects of doing so. Therefore I'd say that the environmental awareness raised in this thread suggests a sticky saying something similar in a general perspective.

Thanks for this thread MetalGod.

[pit]

i'm new here
can you help me by telling me how to start?
i need some ideas and directions....

[markm]

Since I began etching more and more, I have saved the spent stuff because I did not want to do harm to the environment.
I have the convenience of a HazMat disposal near me and I intend to bring them my spent FC.
This is certainly an eye-opening topic for sure.
Although, what was industry doing before the environmentalists stepped in? 
We here are probably just a drop in the bucket  but, it's a serious problem none-the-less.

[puretube]

In our town, the tap water is purer than most botteled "table waters" that are for sale in this country.
I want to stay it that way,
a.o., cause it`s the same water, the local breweries use for their beer.

One way to minimize the waste-material I have bring to the local toxic disposal collection
centre,
is to:
LAYOUT the to-be-etched PCBs such,
that only little copper needs to be etched away.

No "spaghetti" layouts, but nice large groundplanes
and broad supply-rails,
with distances between pads & traces as small as the circuit allows.

I`ve proposed that to "the industry", where I could...

makes your etchant last longer, too.

[markm]

LAYOUT the to-be-etched PCBs such,
that only little copper needs to be etched away.

No "spaghetti" layouts, but nice large groundplanes
and broad supply-rails,
with distances between pads & traces as small as the circuit allows.

I`ve proposed that to "the industry", where I could...

makes your etchant last longer, too.

That's been my attempt in my Layouts.

[gez]

Once it's been neutralized by baking soda, you can use the remaining etchant liquid and some additional water to mix up a part of a bad of ready mixed concrete. This sets into a lump that's environmentally benign. Or you can make a garden wall with etchant-bricks.

I do something similar: mix it with plaster of paris then bin it. 

Metal God, in the UK you can buy a 'safe' kit made by Seno (Rapid sell it, and perhaps ESR) that comes with a bag of plaster/neutraliser.  Although it looks a bit of a rip-off when you get it through - a bag and some rods?? - the etchant that comes in the kit is better than the stuff I've bought anywhere else so it's worth it for that alone, plus it is a very clean way of etching.

http://www.rapidonline.com/productinfo.aspx?kw=seno%20etchant&tier1=Tools%2c+Fasteners+%26+Production+Equipment&tier2=PCB+Equipment&tier3=Etching&tier4=Seno+GS+etching+system&moduleno=29446