Reclaim That Silver...

[Reinhold]

Before you discard your used fixer, toss in some aluminum foil.
In a few moments the aluminum will begin to trade places with the silver ions in the fixer.
The silver will precipitate out as a black sludge of pure silver (mixed with a few bits of leftover aluminum).
The used fixer can now be discarded without concern about silver in the environment.
Silver silver test papers have verified the absence of silver in the solution.

I keep a wide mouth gallon jug just for this task.
I pour in a gallon of used fixer, followed with about a square foot of loosely crumpled aluminum foil.
The aluminum begins to exchange places with the silver almost immediately.
I set the jug aside for a day or three, stirring occasionally.
If the aluminum has completely disappeared, there's still some silver available... I add a bit more Alum.
The idea is to leave a few small bits of aluminum to verify that all of the silver is precipitated.

Siphon off most of the clear liquid being careful not to disturb the silver mud on the bottom of the jug.
Do the same for the next several batches of used fixer.
After a couple of inches of silver mud have accumulated on the bottom, you may want to collect and save it.
Wash the mud by adding a gallon of water, stirring everything, letting it settle, and siphoning off the water.
Do this three or four times to wash out any remaining fixer.
Spread the mud out on a plastic tray and let it evaporate.
It will dry to a very fine powder/dust, handle it gently. Wearing a dust mask is suggested.
There's about 750 grams of silver in the photos...

The silver can be sold to jewelry suppliers but you won't get top dollar due to the aluminum bits.
Alternately, swap the silver with a silversmith friend in exchange for something nice for the wife.

Some may suggest steel wool instead of aluminum.
The heavier steel wool will fall to the bottom and require almost constant agitation.
The oil in steel wool and the rust that invariably forms will make a foul mess.
Your silversmith friend will reject it and the reclaim value will be low.

Reinhold
www.re-inventedPhotoEquip.com
..

[skellum]

How interesting, Reinhold. I don't produce huge amounts of waste fix but this sounds so easy it would be almost criminal not to rescue your silver. I have no idea what waste silver fetches in the UK.
As a dentist, I once did have a vey nice evening out paid for with scrap Gold. Of course, that had a rather different source.

[Adrian Twiss]

Given the price of silver these days it makes sense, especially since your method is simple. Just one question. Where can one sell the sludge (for want of a better word) in the UK. I know some metal reclaimers will collect your fixer for free but I don't think they will go to the trouble of picking up a couple of gallons.

[Xpres]

I think the price of silver is a fraction of what it was a while back, still worth doing, though, for environmental reasons.

[Richard James]

Thanks for that as I was wondering what to do with my old fixer now that a photofinisher/processing lab' that I used to take it to has gone. I didn't like the thought of pouring a polluting heavy metal into the water system.

[DaveP]

Would electrolysis not be an easier way of getting pure silver out of the fixer out for less hassle?

[Adrian Twiss]

I had a word with a silver refining company in Birmingham who sent me their terms of business. I have appended these below. If my maths is correct you would need to send them 30 kilos of sludge to break even

Material Silver bearing sludge material

Quantity As available

Silver Return JBR will pay for 80% of the recoverable silver content as determined by assay.

Charges
Treatment: £8.50 per kilos based on the weight received
Treatment minimum: £250.00 per lot if the total calculated treatment charge is less than £250.00
There will be no other charges

They will test a 10 gramme Sample free of charge.

[Adrian Twiss]

Originally Posted by Xpres

I think the price of silver is a fraction of what it was a while back, still worth doing, though, for environmental reasons.

Silver is currently approximately £12.60 per troy ounce (a troy ounce is about 31 grammes) The price seems to have dropped a bit. However I bet Ilford wont be reducing their prices any time soon.

[JOReynolds]

Originally Posted by MAeon

Thinking about that sludge, what temperature would one need to get to, to melt the silver out of it? Or does it not work like that? I would love the excuse to buy one of those mini furnaces to start making little blocks of silver.

I remember visiting a photo-processing lab where an ambulance was parked outside. A technician had evidently dried a pile of sludge from a commercial steel-wool cell on a paving slab, attacked it with an oxy-propane torch and was overcome by fumes.
It is easy to recover silver electrolytically to a useful purity if the liquor is stirred effectively (info if anyone is interested), but leave the refining to someone else!

[Reinhold]

Originally Posted by MAeon

Thinking about that sludge, what temperature would one need to get to, to melt the silver out of it? Or does it not work like that? I would love the excuse to buy one of those mini furnaces to start making little blocks of silver.

The melt point of silver is 961°c, aluminum is 660°c.

I'm not certain if the aluminum would form an amalgam (or alloy) with silver.
Before trying a furnace, I would dissolve the aluminum bits by washing the sludge in a solution of sodium hydroxide, followed by a clear water wash.

Don't try to melt the dry sludge with a torch, you'll just blow that superfine dust all over the place...

80 litres... wow, that's a genuine silver mine !!

Reinhold