Unexposed photo paper

[goldsilverpro]

If you don't have a rotating cathode electrolysis unit (very expensive), you won't have much luck plating out the silver. You'll have a black mess. I personally would use sodium sulfide to precipitate silver sulfide, as per Manuel's method, and then melt in a crucible furnace with lengths of rebar.

 

[Juan Manuel Arcos Frank]

Pikpok:

Forget electrolysis...focus on sodium sulfide or metallic replacement processes.

Kindest regards.

Manuel

 

[pikpok]

hi all !
because i'm stubborn as a mule im make new electrolysis unit and this work fine :evil:
from minute to minute i'm got more black powder on my Anode .
Next question is what is next?
To black powder add borax and melt ?
or any other idea what i'm can do ?

 

[jimdoc]

hi all !
because i'm stubborn as a mule im make new electrolysis unit and this work fine :evil:
from minute to minute i'm got more black powder on my Anode .
Next question is what is next?
To black powder add borax and melt ?
or any other idea what i'm can do ?

You can listen to Manuel.

Jim

 

[Anonymous]

You can listen to Manuel.

Jim

I think that's a good post that's actually helpful. :shock:

 

[nickvc]

If GSP or Manuel post about silver recovery I'd advise to listen.......

 

[butcher]

pikpok,

You should listen to GSP and Manuel.

Electrolytic recovery of silver from a thiosulfate solution will not recover all of the silver from solution, if the process is done right you can deplete solution of a good portion of silver from the solution with this method, but it has to be done within strict parameters, and you will not get all of the silver out. the reason for a rotating drum cathode (or pumping solution over the cathode is to keep the silver solution in the vicinity of the cathode, otherwise the silver will form a sulfide,and you will gas off Hydrogen sulfide gas (dangerous)as you decompose the thiosulfate electrolyte, keeping the electrolyte pH in a proper range is also important in the electrolytic recovery method, too high of a pH can also cause problems and if ammonium thiosulfate is involved can produce ammonia, as well as several other factors that need to be considered.

Cementing the silver out with a metal replacement reaction, or precipitating the silver out as a sulfide with sodium sulfide, or potassium sulfide will get all of the silver out of solution, and you will have a lot less trouble using these processes.

Listen to the professionals in this, take their advice.

The black powder you have now is possibly a silver sulfide, and I bet most of your silver is still in solution, my guess here of coarse.

If the black powder is silver sulfide you will need to convert it to silver in the melt (using iron) as GSP had referred to previously.

Edited to correct mistake in wording of chemical compound used, thanks Dave for catching that mistake.

 

[rickbb]

Black powder in your cell tells us that you have too much current converting the silver metal into silver sulfide as Butcher has pointed out. Making your own cell is hard to do, the current density is very low and hard to manage, it's why commercial units are not cheap, and home made units are frustrating to get setup right.

They also depend on a certain amount of silver to be dissolved in solution, if you have too little in solution even a very low current will "burn", (for lack of a better way to say it), the silver converting it to sulfides. Commercial units have circuitry to detect the dissolved metal content and shut off or ramp up the current based on how much silver is in solution.

The only reason I mentioned it was because you stated you had a large volume to process. A commercial film/paper processer with an inline commercial recovery unit would be an very efficient method for a continuous large volume of film/paper, but does require a significant purchase of equipment.

I spent many years in the printing business and my setup would yield around 20 pounds of almost pure silver flake every 3 months. All you have to do is feed it the material. If you have a steady supply to process and can justify the cost, I'd look at purchasing the right tools for this.

If this is a one shot thing then a metal or chemical replacement method such has been recommended would be better for you.

 

[pikpok]

I spent many years in the printing business and my setup would yield around 20 pounds of almost pure silver flake every 3 months. All you have to do is feed it the material. If you have a steady supply to process and can justify the cost, I'd look at purchasing the right tools for this.

Can you tell me about the process by PM ?

 

[kurtak]

Ok - here are some pics of some silver I smelted from silver sulfide yesterday - The Ag/sulfide was given to me by a guy that used to have a one hour photo shop & was recovered from his picture fixer solutions - this same guy gave me about 20 pounds of this same material back in 2011 when I was still learning about refining so back then I posted a question about it - here is a link to that discussion --- http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=12404#p122640 --- there is also a discussion about acetylide's in that thread that some of you may find interesting

pikpok - follow the instructions given you by GSP & Manuel - they are the pros in dealing with this kind of material

when smelting your Ag sulfide you want to use a flux of 50/50 borax/soda ash ( I add a "little" fluorspar to make the flux more fluid in the smelt which helps with circulation in the crucible - you don't need it though) you also need a cone mold to pour your smelt into - a cone mold helps your metals separate from the slag & helps prevent ball metal from hanging up in the slag (a little fluorspar in the flux also helps prevent ball metal hanging up in the slag because it makes your flux more fluid when you pour to the cone mold - but again not needed)

be sure to put a piece of rebar (or other iron) in your crucible when you do the smelt - it the chemical reaction between the flux & the iron that causes the conversion of the silver sulfide to silver

Kurt

 

[rickbb]

No need to PM the process, it's quite simple.

Go to a supplier of equipment to the printing industry. Purchase a graphics arts film processer and silver recovery unit. Have them install it and show you it's operation.

Yes it may be a few thousand dollars, but how much film/paper do you have? How much silver will you get? Will this investment pay for itself?

All questions you should be asking first instead of how do I get the silver now. Research the cost benefit ratio of each method first. Compare that to how much material you have/can get and how long will the stream of material last, etc.

You may be able to find good used systems from people who refurbish them for sale. There are a lot of fully automated systems that came out of retail stores from a few years back that offered 1 hour photo developing.

Since the world has switched to digital photography and printing there should be many units on the market.

Google, eBay and Amazon are good places to start looking.

Otherwise you should follow the advise for chemical or metal replacement to recovery the silver that has been given.

Those guys have more knowledge on the subject than anyone I know of.

 

[Juan Manuel Arcos Frank]

Pikpok:

I think you like to walk...but not on the road and it is OK...It remembers me when I was young and made a lot of mistakes.

Do you really think that making an electrolytic cell is just matter of connecting two wires in a battery?...No way..it is more complicated than that...Do you want to take a look?...Ok...I am posting for you a diagram of my ESRU.

Of course...there are non rotating processes but I have never tried them...Do you want to try it?,OK,here is a rare patent about it ,do it, but remember that you asked for it and you will do it at your own risk.

Keep us posted about your progress.

Good luck.

Kindest regards.

Manuel

 

[fonnie]

I have a thought of my own,

creating a electrolysis cell is not that difficult, even with fixed electrodes.

for the cathode, take some stainless steel sheet metal (304 or 316 should do)
for the anode, take some Arc Air electrodes (from a friendly welding company, used for weld removal). Those are carbon with a thin copper foil.

Strip the copper foil for almost the entire length (leaving some for better contact)

take a plastic container (storage box) and and suspend the electrode at a small distance from each other (1 inch)

now you need to pump the fixer around, so a small pump (fixer is corrosive, so select a good one) will do, as long as you keep the fixer flowing by the electrodes, keeping fresh fixer around the electrodes

you will need a power-source, preferably with adjustable current and voltage.

I work with badges of about 30 - 50 liter, pumping around, and adjusting current as the silvercontents goes down.

Don't expect to recover all the silver, it only works until a certain level. and you still have fixer as a waste.

if you keep current setting low (depending on the cathode surface) it will give you a shiny silver deposit, and no black sludge. It's a game of finding the best setting.

Current is the parameter, voltage will follow, so powersource on adjustable current, start low.

if your are going to process some 1000liters, it might take some time.

Never calculated the real cost of the project, most of the items were salvaged, but there is of course the electricity to consider.

I will try to take some photo's of my setup and try to post them

best regards

Fonnie

 

[pikpok]

hi all
fonnie u project are awesome
have 2 anode ?
im know fixer is corrosive the best idea is using pump for aquarists there are only plastic and magnesium :mrgreen:
today try will make unit like you then im post my progess here .

best regards
Peter

 

[canukgold7]

The best and easiest way to recover silver from un-exposed film/paper is to use the normal photographic fixer to strip it.

Then use an electrolytic recovery unit on the used fixer.

This will yield 97%+ pure silver flake right away with no chemical processes to go though.

Hi, please send me info about the recovery unit which you use.