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deleted
16 Posts |
 Posted - 04/19/2008 : 23:16:26
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The company I work for makes disposable surgical forceps with silver plated tips.
The silver is plated by dipping the tips into various mixtures of nitric acid and some solution with silver ions in it. I am not exactly sure how the process works...but.
The CEO of the company knows I collect silver coins and offered me the used mixture instead (half jokingly), saying the have to pay to get rid of it.
Can I take it off his hands and make any money by scraping it? Possibly charge him to take it as well, but less than the other guys charge?
Anyone know about the silver plating ion mixture?
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16 Posts |
Posted - 04/19/2008 : 23:51:39
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| The process they use is an electro-plating process that uses cyanide, nitric acid and some other chemicals. |
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psi
Penny Collector Member
Canada
399 Posts |
Posted - 04/20/2008 : 00:27:30
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A few sites I looked at on silver plating mentioned cyanide in the plating solution.. I'd find out as much as I could about the specific process they use (is there other stuff in the solution than just silver and nitrate ions?)
Edit: posted without refreshing so I didn't see your second post.. maybe it's because of the cyanide disposal that people charge to take the waste solution? Wouldn't want to take the risk of dealing with something that toxic myself, but to each their own.. |
Edited by - psi on 04/20/2008 00:39:41 |
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Ardent Listener
Administrator
USA
4841 Posts |
Posted - 04/20/2008 : 04:53:49
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| I wouldn't get involved with anything like that too. |
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Think positive. |
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tyoon21
Penny Sorter Member
52 Posts |
Posted - 04/20/2008 : 11:23:08
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Illum,
Go on google and type in silver recovery. There are some companies out there that do this type of recovery for x-ray fixer solution. Maybe they can help.
Another thing you can do is register on goldrefiningforum.com and ask there. They have a section devoted to silver recovery. Lots of good and friendly people there who can help.
Good luck!
Tom |
Take this job and shove it. I don't want to work here no more... |
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silverhalide
Penny Sorter Member
92 Posts |
Posted - 04/20/2008 : 18:21:06
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| In the days when the Hunt brothers tried to corner the silver market while I was in college I would extract silver solution with a iron cathode. If I got the physical xrays I used nitric acid to get the silver into solution then of course used the cathode. Kodak's publication J215 gives you a more detailed information on what to do. |
Edited by - silverhalide on 04/20/2008 18:24:59 |
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tyoon21
Penny Sorter Member
52 Posts |
Posted - 04/20/2008 : 19:51:59
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quote:
Originally posted by silverhalide
In the days when the Hunt brothers tried to corner the silver market while I was in college I would extract silver solution with a iron cathode. If I got the physical xrays I used nitric acid to get the silver into solution then of course used the cathode. Kodak's publication J215 gives you a more detailed information on what to do.
Silverhalide,
Few questions if I may:
1. What concentration of nitric did you use for the xrays?
2. How long did you soak the xrays?
3. Did you have to heat the solution?
Thanks in advance! I have a bunch of xray film that I am contemplating processing myself or sending it out.
Tom |
Take this job and shove it. I don't want to work here no more... |
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silverhalide
Penny Sorter Member
92 Posts |
Posted - 04/24/2008 : 15:36:14
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1 at the time I used a 1.5 mol solution of HNO3. You probably could use a weaker acid down to 1 mol (you might be forced to)
2 Until the xray is clear
3. No Heat and would not recommend "experimenting" without a laboratory hood
I think I used a graphite anode and stainless steel cathode.
Another consideration is acid prices have really skyrocketed in price and supplies of it are tight.
And of course you will also have to refine the silver |
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Saul Mine
Penny Collector Member
USA
343 Posts |
Posted - 04/26/2008 : 00:06:06
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Cyanide in any acid releases fumes. I doubt this solution has both. The first thing you do with cyanide is get the pH up to 11 so it doesn't kill you. Then you can figure out how to neutralize it.
Maybe when he says nitric acid he means silver nitrate. That is likely because nitrate is the only soluble form of silver. Add salt and the silver will settle out as a grey powder - silver chloride. You can sell that to a smelter. It is 75% pure.
But first you need to be sure you're not getting a suicide kit. |
A penny sorted is a penny earned!
Please use tinyurl.com to post links. Long links make posts hard to read. |
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silverhalide
Penny Sorter Member
92 Posts |
Posted - 04/26/2008 : 12:06:47
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| I agree with Saul whatever you do don't mix cyanide with HNO3!!!! These are the two different ways you can extract silver. Using nitric acid is safer and is the best way to go for extracting silver halides out of a photographic film but I am 100% sure cyanide would be more effective stripping the plated metal but its definitely more dangerous to use. I am sure you could then use the electrowhinning process to get the silver metal. |
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goldsilverpro
Penny Sorter Member
26 Posts |
Posted - 05/23/2008 : 09:36:24
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illum,
Find out from your boss the make up of the plating solution he's using. A make-up sheet surely came with the bath. There are a few non-cyanide plating solutions on the market - it will say on the manufacturer's literature. If it is cyanide, I would avoid it like the plague. Cyanide is fairly safe if you are knowledgeable. No offense, but it is obvious that you are not.
tyoon21,
Here's part of a post on film that I made recently on another forum. All in all, to produce silver of a salable purity, you would lose a lot of money and time doing it yourself. It would cost you a lot more than the silver is worth, unless you knew what you were doing and were running many tons per month. Find a buyer and sell it. If you can, sell directly to a film refiner. There are many middle men in this business and they all must make money.
I refined film, commercially, on a grand scale, for about 10 years. I
spent 4 years working as a chemist for a company that processed about
1 million pounds of film per month. I also owned a gold/silver
refinery and, among many other things, I was set up to run about 1000
pounds of film per day, in a tumbler.
Here's a general, simplified outline:
First of all, realize that developed, medical x-ray film is fairly lo
grade - about 0.1 tr.oz. of silver/pound of film. Developed litho
(printing - usually newpaper) film will average about twice that
amount. To profit from either, you have to be properly set up to run a
lot of it. Even with the high price of silver, this is a low margin,
high volume business.
After film is developed and run through the fixer, about half of the
original silver remains on the PET plastic film, as finely divided
black silver metal. It is held on the film by a gelatin layer. The
blacker the film, the higher the silver content.
Burning film is now out of vogue, due to the cost of setting up to
legally prevent air pollution. Also, about 25% of the silver content
goes up with the smoke. This can be caught in an expensive baghouse.
Also, the scrap value of the PET base is lost.
Another old way (and, technically, the best way) was to dissolve the
silver in cyanide. It was then plated out and the cyanide solution was
reused. The EPA pretty much put an end to this method when a worker
died in Chicago, in the '70s. It was front page news and, I remember
that 60 Minutes even did a segment on it.
Nowadays, chemical methods are used to remove the gelatin/silver from
the PET base. With an efficient process, the PET will be clean and can
be sold. The most common chemicals used are a warm enzyme/baking soda
combination or a hot, weak, sodium hydroxide solution. The stripping
is usually done in a tumbler. Before stripping, the film is chopped to
produce about 1/4" pieces. If it is not chopped, the sheets of film,
when wet, will stick together and prevent a lot of the silver from
stripping. The gelatin/silver is collected and incinerated, and then
the silver is melted and purified.
A much less common method is to leach the film with a chloride or
chlorine chemical to remove the gelatin/silver and, at the same time,
convert the silver to silver chloride (AgCl). This can be done with
bleach or a dilute hydrochloric acid. The AgCl can be converted
to silver with a number of processes, such as Karo syrup and lye. The
AgCl can also be dissolved in hypo (sodium thiosulfate) and then the
silver can be plated out on a standard, rotating cathode, electrolytic
cell that is designed for running fixer (hypo) solutions. All these
chloride methods are generally not used because of costs and/or
efficiency.
Dilute nitric acid could be used but, I've never seen it used in
production. I'm sure it has to do with cost and the necessary control
of the toxic nitric oxide fumes that are generated.
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Edited by - goldsilverpro on 05/23/2008 09:39:24 |
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MormonMetal
Penny Pincher Member
USA
150 Posts |
Posted - 05/23/2008 : 19:15:42
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| I am always amazed at the number of incredibly intelligent people we have on board here. |
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tyoon21
Penny Sorter Member
52 Posts |
Posted - 05/23/2008 : 20:19:23
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Goldsilverpro,
Thanks for the help! Seems like I should stick to just collecting the stuff and selling it off. I'm essentially clueless when it comes to messing around with chemicals.
Good to see you here. I am almost 100% positive I have seen you before on goldrefiningforum.com. I still check that site out quite a bit. Great info on there.
Thanks again!
Tom |
Take this job and shove it. I don't want to work here no more... |
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Kurr
1000+ Penny Miser Member
2906 Posts |
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Can you scrap silver ion mixture,
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