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Philippe Gauthier
16-Feb-2004, 22:04
I've noticed that silver tends to precipitate as flakes in old film fixer left to sit for a couple of weeks. Has anyone here tried to recycle it? I'm not thinking of getting metallic silver, for which I have no use, but to get silver nitrate, which is expensive and used in small quantities in several cool alt processes.

I know that you must dissolve silver in nitric acid to get silver nitrate, but pure nitric acid is nasty stuff; does anyone knows of the lowest concentration that would work? Are the flakes pure enough to be turned in sufficiently high grade silver nitrate? Other safety considerations?

My assumption here that the silver which precipitates spontaneously will be purer than the mixed silver/iodine sludge that you get with the usual "iron sponge" trick to remove the silver from the fixer. Is this a reasonable hypothesis?

Capocheny
16-Feb-2004, 23:01
Hi,

Good question Philippe...

When I worked for a newspaper back in the early 80s they had a silver recovery process in place. However, it's viable only if you're putting through quite a bit of raw materials.

I would contact a local newspaper and ask them if they have such a recovery system in place. Alternatively, you can also contact either Kodak or Ilford and query them about this. I'd be awfully surprised if they didn't.

IMHO, I think it's a good thing to do... much safer for the environment.

Cheers

Abe Slamowitz
17-Feb-2004, 06:21
All labs have to recycle silver. However you do need to run quite a large amount of chemical to get a few drops of silver. you can buy a can and collect your chemicals until you have a large batch and than you must run many more batches to get any amount of silver. It's good for the environment and makes money for the big labs.

jnantz
17-Feb-2004, 07:54
hi philippe:

i'm not sure where you live, but these guys are on the west coast ( usa ) and convert spent photochemicals into fertilizer.

http://www.itronics.com/index.html

Philippe Gauthier
17-Feb-2004, 09:12
Just be clear - the process doesn't have to make much business sense. I can access my own processing and some of my photo club's. Even 10 or 20 grams of silver in a year would be great if I can easily (and relatively cheaply) turn it into useful silver nitrate. I could some milleage on a salted paper recipe that requires only 12 grams of silver nitrate. It would be satisfying to get it from recycled silvr, even if buying such a small amount of silver isn't THAT expensive.

Any hints?

Rob Tucher
17-Feb-2004, 14:00
One thing not many know is that it is highly illegal for anyone to dump untreated fixer down the drain. As rare as it is that anyone is made aware of this and as hard as it is to come across companies that make silver recovery paraphernalia, you can be fined big time if you get caught. These days waste water companies have chemical sniffers that can locate polluters. You can be fined thousands based on your buying and usage history verified by your receipts for chemistry. I know of a small time black and white guy who was fined $15,000 but later had it lowered to $7500 for dumping. It's done by state DEPs but is based in federal law. Not to be an alarmist but this thread kind of indicated to me that not many people know about this.

Mike Chini
17-Feb-2004, 17:04
Considering all of the pollutants we all dump down the drain and in the garbage - on a regular basis and in bulk, (bleach, household cleaners, plastics, paints, cosmetics, rotted food, metals etc.) that seems absurd.

jnantz
17-Feb-2004, 17:46
Iknow what you mean Rob: Where I live people get fined $10,000 / day that they are "non-complient". The authorities test down to 3pts/ million ( lowest amount they can detect before it is deemed "undetectable").

As for the " you dump everything else down the drain " argument, everything else isn't a heavy metal, or illegal ;)

goodlight JAKE

darter
17-Feb-2004, 19:40
Fines for illegal dumping are generally reserved for commercial users, not for those who merely develop their own film. Of course, this varies by local ordinance. I uncovered an article that said that steel wool placed in used fixer will precipitate the silver into a sludge that can be eventually be collected and dumped as solid waste (or hopefully, recovered). This is far less harmful than letting it enter the liquid waste stream. Even the smallest silver recovery systems available are designed for those who use more fixer than the average hobbyist. I've heard that some schools and labs will accept used fixer, so it is worth checking local high schools or colleges.

Philippe Gauthier
17-Feb-2004, 21:56
(sigh)

OK, I'll try one last time. I live in Canada and the american law on toxic waste does not apply to me. I don't want to recuperate silver to make some real money or even just to protect the environment, I just want to recuperate a few grams here and there just for the sake of doing it and making my own silver nitrate - I'd eventually like to get 12 to 15 grams of it just to try the salt paper technique.

I don't think it's an absurd objective even in the context of the home darkroom; now, how can it be done in practice and as safely as possible, that's the question. The rest is, as far as I'm concerned, off topic. BTW, I already have a local supplier for silver nitrate.But I'd like to do it myself, if possible, just for the fun of playing with chemicals. That's why we play with alt techniques, isn't it?

Rob Tucher
18-Feb-2004, 10:41
Philippe, it may be frustrating to ask a question and not get a specific answer but a forum is give and take and it by nature goes where it goes. The answer to your question is pretty complicated but some of it is inside these responses. You can gather silver through a number of means. Electrolytic machines are available and collect silver plate on either the anode or cathode, I forget which, and then you scrape it off. I got one on Ebay.

The precipitate type of collector can get expensive and involved and is usually meant for large users of chemistry, but basically is the steel wool replacement type. If you don't run a huge amount of chemistry through these then the steel wool corrodes and crumbles before you can collect and it's a waste. There are small steel wool pour-through types of buckets for low volume (just gravity feed rather than pump).

The problem with all the types is that the refining end of it is the complicated part. I'm not sure how you could. It takes baking to dry sludge, then firing at high temperatures to separate, and then a few more steps. I visited a refiner and he walked me through the plant and it is a big, costly operation just to get down to the basics.

Look up silver refining and silver recovery and explore the potential with them. They may tell you it isn't possible or have some hints. The guy I sell my stuff to is very helpful and open.

Jake, you're very right. Ignorance of the law has never been a defense. And it IS NOT limited to commercial only, Phil. The guy I was talking about was not a pro and did nothing commercial. Heavy metals are heavy metals no matter what the source and unless you live in a very lax area you're taking a big chance assuming you won't get caught.

Philippe Gauthier
18-Feb-2004, 16:55
Thanks Rob, you're a champ. You don't hve all the answers, but at least these are useful starting points. I had no idea this whole thing was so complicated - and the US law so difficult to comply with because there is little technology available.

Wayne
18-Feb-2004, 18:09
and the US law so difficult to comply with because there is little technology available.

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Not hard at all, you simply dispose of used fixer at a hazardous waste facility if you cant de-silver it. In my area disposal is free for non-commercial users.

John_6081
21-Nov-2005, 00:42
I am a professional in this field. I have been recovering silver for the labs for 23 years now.
should you need a help contact me at allaboutelectric@peoplepc.com

Richard Ide
21-Nov-2005, 07:35
Hi Phillippe

Silver recovered from fixer will have impurities in it. I would buy silver nitrate ready to use. Generally, photographic chemicals are very pure so as not to introduce contaminants which might have an adverse effect upon a process. Iron is one metal which must be avoided completely.
When I was recovering silver a few years ago, I was paid for about 85% of the weight I collected. I remember when the Ontario Ministry of the Environment made it necessary to register as a hazardous waste generator. If I recall, (please check) personal use at home by photographers was unregulated because of the very small quantities involved. If selling recovered silver, one would probably run in to problems not being licenced and not profitable unless you had at least a couple of hundred ounces. I recover silver at home from spent fixer just to keep it out of the environment. Nitric acid can be nasty stuff so I would avoid trying to do it myself.

Richard

N Dhananjay
21-Nov-2005, 08:38
Porters camera (www.porters.com) sells a silver recovery unit that is small and reasonably priced. Cheers, DJ

n aveed b utt
16-Apr-2006, 16:37
hello, Sir

I want to know How I can meaure the exact quantity of silver in waste chemical

did u have any method or equipment pls tell me,

I know only copper test,

Thanks,

Richard Ide
16-Apr-2006, 19:54
Kodak supplied fixer test strips in a booklet. You would tear a strip off and immerse the end in the fixer. The colour would change as the concentration of silver increased. There was a colour chart printed on the back of the book. You matched the colour of your strip to the chart and the concentration in ounces per gallon or grams per litre was given for that particular concentration