Spent Fixer and Steel wool, what's supposed to happen?

[Darkroom317]

I tired this method of silver removal over the past couple of days with around three gallons. However, looking at the bottom of the container, what is black just seems to be the steel wool. When I started to remove the fixer it was red in color, so I am assuming that the reaction worked. I also was able to smell sulfur until I removed the steel wool from the solution.

I've also seen conflicting reports on what happens during this reaction. Some say the silver adheres to the steel wool and some say it collects at the bottom as black sludge. Which of these is true?

I would really like this to work and I don't like the idea of a lot of silver going down the drain.

 

[richard ide]

The iron replaces the silver in solution and the silver plates out on the steel. As the iron is used up you will get a silver sludge in the bottom of the container. You can see what happens if you put a solid piece in the solution but it takes a while. The reason for the steel wool is the surface area.

 

[Ross Chambers]

You could ask the brothers who managed a government owned motion picture lab in a Southern Hemisphere city. They had a silver recovery unit, but claimed ignorance of its function when the Arri engineers dropped in from Germany to inspect the set up, saying that they didn't know what its function was. They had been flogging off the silver for years.

 

[bdial]

A photo school here in the Northast spent years dumping their fixer down the drain, and ended up with the pipes clogged with silver that had replaced the iron.
The steel wool method works, but it's messy and leaves you with this goo that is still hard to deal with. I switched to a Silver Magnet which removes the silver by electrolysis.

 

[removed account4]

hi dan

i never liked the steel wool method, while inexpensive, it was messy.
yours system seems to be working, if you are getting
some sort of sludge in your once clear fixer, and "stuff"
on your steel wool. i may be wrong, but the red-stuff might be rust.

i used to use copper flashing instead.
it was cheap and easy and worked great.
i used to be an avid skiier, and sharpened/waxed my skis
so i had what in the ski-industry is called " a metal scraper "

my methodology was this ..
get copper flashing and shine it up extra shiny with brasso or similar
material to expose as many ions as possible.
stick the flashing into a plastic bucket with the spent fixer
the copper usually changed tone+color after a few days ..
so i would pour the fixer into another bucket, through a filter.
there was always gunk at the bottom of the fixer.
i would dry off the flashing and scrape off the layer of stuff on the copper.
and start all over again. i liked the copper because you could actually keep using it
after you scraped it down and got it shiny again ...

now there was this gross sludge, not so much messy but something else to deal with.

"trickle tanks" pretty much do the exact thing that you are doing, but all that stuff is encapsulated
inside the tank.


good luck

john

 

[Wade D]

I used to use powdered zinc to reclaim silver. A few ounces thoroughly mixed into a gallon of spent fixer. The mix is left to settle for a few days then the liquid is poured off. What is left is a dark gray sludge which is then dried and stored.
When a few pounds had accumulated I sent it off for refining. After an assay the result was 80% silver and money in my pocket.
It was messy but very effective when I used to have large volume.

 

[Mainecoonmaniac]

One way is to fine a university or college with a photo or art program that disposes their used fixer properly. Kindly ask them if they will allow you to dump a few gallons into their used fix. But don't dump it down the drain because silver is toxic.

 

[CBG]

I have kept my eye on information on silver reclamation but I have never heard of the cooper flashing and powdered zinc methods. Can you elaborate on how they work?

 

[removed account4]

copper flashing does the same thing that aluminum foil, or steel wool or iron ...
it does "ionic transfer" ... and plates out silver in exchange for whatever other metal
you may be using ... i would imagine zinc might do something similar ...

 

[CBG]

Hmmmm, I never heard of using aluminum foil for plate out the silver either. Old dog, new trick.

 

[removed account4]

Hmmmm, I never heard of using aluminum foil for plate out the silver either. Old dog, new trick.

me neither !
in the spent fixer - the poll thread someone spoke about that.
it seemed pretty cool ( and inexpensive ! )

 

[Wade D]

I have kept my eye on information on silver reclamation but I have never heard of the cooper flashing and powdered zinc methods. Can you elaborate on how they work?

The chemist who taught me this method used it in large scale silver reclaiming. All he told me is that the zinc particles attract many times their weight in silver ions.
I used it on a much smaller volume and it works but as stated is quite messy.

 

[CBG]

It does sound so simple. But to actually use the zinc technique I have a few questions. How does one know how much zinc powder to use? What is too much zinc powder and what's too little? How does one know when all silver has been pulled out of solution? Where does one get zinc powder? Are there any other basic how-to items I should know?

 

[Q.G.]

And what do you all do with the sludge thus created?

 

[Tom Kershaw]

In what type of container does one convert the silver and produce the gray sludge? My experience of using bottles has been that you end up with a very difficult to empty product; perhaps a wide body container (e.g. a washing up bowl) is more appropriate, providing spill risk can be dealt with.

Tom

 

[Ian Grant]

The chemist who taught me this method used it in large scale silver reclaiming. All he told me is that the zinc particles attract many times their weight in silver ions.
I used it on a much smaller volume and it works but as stated is quite messy.

For many years I used zinc powder to recover silver from solutions and also in Gold refining where we ended up with large quantiyies of Silver Chloride converting this back to silver with Zinc.

Ian

 

[Anon Ymous]

It does sound so simple. But to actually use the zinc technique I have a few questions. How does one know how much zinc powder to use? What is too much zinc powder and what's too little? How does one know when all silver has been pulled out of solution? Where does one get zinc powder? Are there any other basic how-to items I should know?

I only have basic chemistry knowledge, but here are some facts:

1) Silver's atomic weight is 107,86 and zinc's is 65,38.
2) Silver's oxidation number is +1 and zinc's is +2, which means that an atom of zinc will precipitate 2 atoms of silver.

So, that roughly means that 1 gram of zinc will precipitate 3,3 grams of silver.

 

[Wade D]

All good questions and answers. I haven't used this method in 30 years but assume powdered zinc would still be available from a chemical supply firm. I bought mine from Allied Chemical. The amount used was a guess on my part.
1 ounce per gallon seemed to work well. The sludge, after removing the liquid, was dried in the plastic jug used for the process then broken out and stored in a sealed canning jar. I have no idea how much zinc was used in the large scale process but they were treating 5000 gallons of spent fixer at a time and getting about 1100 pounds of dried sludge which was about 80% silver so it was quite profitable.

 

[Neal]

Dear Darkroom317,

Check out the "Silver Magnet". One of the APUG advertisers markets it as well as the manufacturer. Porter's might still have them as well.

It's easy to use and, according to the test strips, works very well for me.

Neal Wydra

 

[Darkroom317]

Dear Darkroom317,

Check out the "Silver Magnet". One of the APUG advertisers markets it as well as the manufacturer. Porter's might still have them as well.

Neal Wydra

Thanks for all the replies. That is what I eventually want to get.

 

[CBG]

Thanks for all the information! Never knew it could be so simple. I do have a silver magnet, but I like to have a backup strategy.

 

[Ian Grant]

In larger scale electrolytic silver recovery (similar to the Silver Magnet) a wire wool tailing unit has used to because these electrolytic plating units can only remove silver to a level where 5-10ppm silver is left in solution.

Ian