sena
Well-known member
- Joined
- Jul 21, 2011
- Messages
- 208
Silver from xray flim
- Thread starter sena
- Start date
Help Support Gold Refining Forum:
The silver on film is quite pure to start with, very possibly 99.99%. Therefore, if you have not contaminated the silver with any other metals during the processing, the bar will be pure. The bar looks pretty good to me, at least on the bottom. How much film did you process to get that 600 grams? I would guess about 200 pounds, if it were standard developed rare earth x-ray film. If it were Dryview, from 200-500 pounds.
After running assays on about 40 million pounds of medical x-ray film, over a 4 year period, and seeing it all processed, I have never seen any that ran nearly as high as yours, .26 tr.oz./pound (based on the figures you gave - 200kg of film yielding 3.6kg of silver), unless it was manufactured before about 1980-1985. Even the undeveloped medical x-ray film made since 1985 only runs about .18. Four mil thick Litho film, from newspaper printing, could run that high but it would be about 98% black.
Developed Industrial X-ray averages about .26. Developed Industrial appears to be 100% black, from edge to edge, with no borders. However, when you put a very bright light behind it, you can see the image, albeit faintly. Is that what you were processing? If not, exactly what type film were you processing and how old was it?
Developed Industrial X-ray averages about .26. Developed Industrial appears to be 100% black, from edge to edge, with no borders. However, when you put a very bright light behind it, you can see the image, albeit faintly. Is that what you were processing? If not, exactly what type film were you processing and how old was it?
That was a good lick. Industrial x-ray scrap is the best and there's not that much out there. And it looks like you did an excellent job of processing and got all, or most all, of the silver. Did you shred the film?
It was nice to see that my numbers were right on.
It was nice to see that my numbers were right on.
sena
Well-known member
- Joined
- Jul 21, 2011
- Messages
- 208
goldsilverpro said:
As i do this in a small scale i dipped the flim as it is one by one ( shredding makes quicker), and later i washed this flim in an washing machine. Earlier when i was using Nitiric it made a mess, during heating the sludge , i got my stainless steel vessel damaged due the heat and the hcl content in the Sludge made a stainless steel to erode ,switching to Naoh is far safer than using nitric which was a time consuming..
sena said:
Wow! That's a lot of sheets to run one by one. It must have taken you forever. I'm thinking that there are about 18 sheets of normal sized medical x-rays per pound. Industrial x-ray sheets are normally much smaller, and you ran 440 pounds. Maybe you could rig up some sort of plastic frame with slots in it (or string small insulated wires as separators) to run multiple sheets at the same time and keep them separated.
What strength NaOH did you use? Did you heat it? How long did it take to strip one sheet?
When I got the sludge, I tried leaching it in 10% sulfuric acid (not HCl). This did reduce the volume of sludge about 60% and there was less to incinerate. Usually, though, I just incinerated the sludge without first treating it with acid. I didn't use HCl for fear of converting some of the silver to silver chloride. When you melted and cast the bar and let it cool, did you have a thin greenish or rainbow colored layer between the silver and the slag? If so, that is unconverted silver chloride. Once it's melted, it's hard to process. A place I worked blended about 25# of sodium carbonate (soda ash) and 50# of borax with about 200# of incinerated sludge before melting. It must be well blended. They put it all in a sealed drum, along with a few lengths of steel rod, and put it on a rotating tumbler for about 30 minutes to blend it. During melting, the soda ash was an insurance policy and converted any silver halides to silver metal. The soda ash is hell on crucibles, however.
sena
Well-known member
- Joined
- Jul 21, 2011
- Messages
- 208
Well My friend , i liked the term you said " Insurance policy " . yesterday i started a new batch 200kg , i used 4kgs of Naoh , completed it today soaking ( 2persons beside me for helping), well do the siphoning next morning . i didnt heat it , i used the water which was used for the earlier batch for washing the flims . The sludge should be heated till light brown ,usally it took me 2 hrs for 2kg sludge to brown powder . then geting the heated powder i run it in a kitchen Blender ,then i mix it equal volume of borax, mix it manually , then once again use blender for mixing it for a minute( for mixing equally and equal fine particles) , then fire it using oxy actelyne torch. Iam afraid 1 ltr of hcl wont convert the Silver halide(to silver chloride) in 300lts of the Barrel holding soaked as well as the washing solution . more over the sulphuric is more coorosive for metal container , besides it fights when heated which i had bad experience in making holes in ss container while incineration.
I ran with sodium corbonate once when met with silverchloride which was a month ago.using the oxy actelne torch it was a tiresome one , as the reaction takes place on the top layer of the melting pot , there was a lot of sprinkling due to the reaction with oxygen on the top , so i hate it.
I ran with sodium corbonate once when met with silverchloride which was a month ago.using the oxy actelne torch it was a tiresome one , as the reaction takes place on the top layer of the melting pot , there was a lot of sprinkling due to the reaction with oxygen on the top , so i hate it.
Sena,
There are many ways to skin a cat when it comes to processing film. And, you often have to adjust your method to what equipment you have.
And, it's hard to argue with success. From what I've seen, you're doing great. In fact, you're about the first person on the forum (someone correct me if I'm wrong) to get all the silver from the film and get it all into the form of a nice bar. Congratulations! Processing film correctly is much, much more difficult than one first thinks.
Chris
There are many ways to skin a cat when it comes to processing film. And, you often have to adjust your method to what equipment you have.
And, it's hard to argue with success. From what I've seen, you're doing great. In fact, you're about the first person on the forum (someone correct me if I'm wrong) to get all the silver from the film and get it all into the form of a nice bar. Congratulations! Processing film correctly is much, much more difficult than one first thinks.
Chris
