Steel wool silver recovery system

[Blue Nandina]

Hello All- I have recently set up a color darkroom at my house and I am attempting to use the steel wool silver recovery method. I'm on a tight budget and it's just me so I only generate about 5 gallons of used blix (and blix rinse water) per session. I use RA4 chemisrty-in case there is a difference between color and B&W fix reclamation. The research I did before hand made it seem very simple: bucket, steel wool, sit over night, dump everything except the sludge. It may not be the cleanest way but I don't mind the mess of pouring off buckets of treated chemistry.

But I have found myself unsure after actually trying it. So can someone tell me the following:
- how much steel wool do I need to use to effectively treat a 5 gallon bucket of used blix/rinse water?
- how often do i need to change the steel wool?
- how do you know when the silver has seperated out? Does the water change color b/c from the top of a full bucket (with steel wool in the bottom) it all looks the same.

right now I have 1 pack of steel wool (~8-10 bundles) in the bottom and after letting it sit over night i pour off all the fluid to the top of the wool.

I just don't want to go through the trouble of doing this if I'm not actually achieving anything and it's important to me to be as safe as possible.
Any insight would be much appreciated.
Thanks!

 

[Mike Wilde]

Not a bad approach, but I might suggest storing the used developer and bubbling a fish tank air stone thought it to cut its oxygen scavenging demand (the technical term is BOD) befroe flushing it away. Combining it with used stop bath would also neutralize its rather alkaline pH.

As to blix, Kodak sold a pair of cans filled with steel wool that waste wash water would slowly percolate though for its minilab machines at one time.

So if you are trying to do a whole pail of blix, I would not be shy in throwing in a box worth of steel wool pads. If that volume concerns you, rinse what is left over after the decant, and then toss them into a plastic bag stored in the freezer until the next treatment is needed.

I evaporate my waste RA-4 blix to a sludge, and take the resulting sludge to the hazardous waste depot about twice a year.

 

[Blue Nandina]

I'm game for buying lots more steel wool but can you give me an idea of how long it takes to be effective or if it looks any different when it is ready to be disposed of? Any idea how often you have to change the steel wool?

Also that evaporating thing sounds interesting. Can you go into more detail on that? What do you use an how long does it take?
thanks,
BN

 

[richard ide]

IIRC The containers with steel wool for silver recovery were designed to have the solution slowly percolate through them; always being full of solution. Dumping the chemistry would expose the steel wool to the air and result in very fast rusting. When I first started in business; I made a recovery unit with a stainless steel sheet as a cathode and a large piece of graphite as an anode. I used a transformer to reduce 110 volts to 6 volts, a rectifier and a resistor (which seemed to limit current enough to prevent sulphurization). I would put my fixer in a 5 gallon pail with the electrodes hanging on the sides and leave it for 3 or 4 days. I also checked the solution for silver content with test strips (Kodak) and dumped it when no silver was left in solution. You could also just use strips of a baser metal such as copper, zinc or steel. The silver would collect on the metal strip and fall to the bottom of the container.

 

[Mike Wilde]

To evaporate I have a large food service steam table tray about 12x18 or so. In the winter it sits in the garage on top of my vertical freezer, and a gallon will evaporate in about 3 months.

In the spring I move it out to a spot under the roof overhang of the garage where it gets full morning and daytime sun, but cannot get rained on. There I can dry out a gallon in less than 2 weeks.

So I store up spent fix/blix in 2L pop bottles and wait for spring most of the time. When the yard is thawed and dry enough I round up all the fallen limbs, and other yard waste and haul it to the dump, and also visit the hhw depot next door to drop off my sludge and any fresh liquids that have yet to be dried and concentrated.

 

[MattKing]

I'd try contacting John Nanian (jnanian here on APUG). He is selling a "Silver Magnet" - an inexpensive silver recovery unit. All the descriptions I've seen for it are oriented toward black and white fixer, but it may be that it could be used for blix - it cannot hurt to ask!

And I'm sure that if John determines that his Silver Magnet can be used for colour materials, he will be happy to advertise that .

 

[Blue Nandina]

Thanks for the replys. I have contacted John Nanian to explore that option but want to keep digging on the steel wool thing just in case my definition of inexpensive is different from his...or if it won't do for blix.

Evaporation might work in the summer since we get long periods of no rain. I can just put a screen over it to keep junk out and lay it out in full sun. But winter I don't have a spot that would work. Saving it up might work though since I tend to print less in winter anyway. It's an interesting option.

The bucket system would be much more practical if I was only dealing with the blix solution itself (1-2L at a time) but I read somewhere that you need to reclaim from the blix rinse water too. That is really where my volume comes from and what has made the bucket a challenge. I have a "slash tray" next to my processor so the blixed prints come out and fall into some standing water. Usually it's a couple of liters and I use it all day even when I've had to mix new chemistry. It serves as an initial rinse. I then move the prints to a print washer for real cleaning, squeegee and put on a drying rack. The wash water is constantly running and goes down the drain but the "splash" pan gets visibly discolored from taking the initial rinse load all day. Do you guys have any opinions or facts on reclaiming fix/blix rinse water? If I can skip that then the bucket and/or evaporation makes much more sense.

Anyway my current system I avoid the rust issue by filling the bucket with used blix and rinse water and let it sit until I've printed again and have more waste. Usually it's overnight or longer. I then pour off the "clean" chemistry and immediately fill again with new "dirty" chemistry so the steel wool doesn't really ever get exposed to air unless it peaks out as I'm dumping. Any unused chemistry just gets dumped b/c it never picked up the silver from processing in the first place.
Let me know if this all sounds safe enough and where I need to make my changes to keep our water safe-er.
thanks!

 

[Marco B]

I am not entirely sure as to your workflow. Do I understand it right you just want to reclaim the silver from the blix, and dump the treated blix down the drain afterwards?

If so, you might consider to deliver the treated blix at your local municipal waste station. Here in the Netherlands, I can deliver small quantities of chemical waste (paint, fixer, developer, household chemicals etc.) at our waste station free of charge.

As to the rinse water: I doubt if it is of any real use to treat that. Even though it will pick up on small amounts of blix and dissolved silver, the amount will be just a fraction of what is in the blix bath itself.

 

[removed account4]

hi folks ..

i learned from the manufacturer of the recovery systems i distribute
the trickle tanks will work fine with "blix" as well ..
marco has a great solution as well !


john

 

[Athiril]

I recommend trying copper instead.

 

[removed account4]

copper is insanely expensive ....
these days, people ( at least here in the usa )
are stealing copper pipe, wires and conduit
out of houses when people are away on vacation,
vacant buildings and even electrical sub stations, to
sell the copper for $$

i documented a building that was to be demolished a few years back, and thieves
were stealing copper out of it weekly ( thousands of dollars worth!).
on the last day i was there, i was photographing the exterior
( from a high vantage point to show the parapet and clearstory monitor windows &C )
there was a group of 5 people breaking into the building through the rooftop windows.
(you couldn't see them from the street ... )

aside from the excessive cost of copper, one of the other problems is, once you get your sludge
and you scrape the silver off of the copper and dry it out, what do you do with it ?
and how do you know that your copper plated all the silver out of your blix ?

part of the problem with home-brew alternatives is they are not
as efficient as a mechanism that is made specifically for this purpose.
they are less expensive and may work, but you may have some loose ends to tie.

sometimes just taking the spent chemistry to the waste recovery day is the
most feasible, inexpensive and hassle free solution ..

 

[Wayne]

sometimes just taking the spent chemistry to the waste recovery day is the
most feasible, inexpensive and hassle free solution ..

Is the fix "clean" enough of silver after using any of these home brew systems including steel wool and magnets that you don't have to take them to haz waste anyway?

 

[removed account4]

from what i understand, there is a little silver left ( about 50pts / million ) when
you run the fix through an electrolytic unit, but trickle tanks scrub it down to
0 parts / million ... i have no idea what the situation is with home brew units ...

the laws are different no matter where you go,
so it is best to find out in your own location what needs to be done.