Silver from xray flim

[goldsilverpro]

Ralph,

Looks like it's undeveloped Medical x-ray film. Probably worth about $5/#.
https://docs.google.com/viewer?url=http://www.med-x-ray.com/images/Agfa_MI00078.pdf



kevin,

When Manuel mentioned adding alcohol, he was talking about caustic soda and not oxalic acid. Were it me, I wouldn't start combining things willy-nilly. Could get you in trouble. Also, the addition of alcohol was only for dryview, not halide type. A warm or hot caustic soda solution with no alcohol should work fine for halide film. A 10% caustic soda (100g/l) solution will work at about 130F but it will probably etch glass. You can use less caustic but you'll have to raise the temperature a bit. Use a stainless container if you have it. A little agitation always helps speed things up.

 

[kjavanb123]

GSP,

I just realized that after 20mins into the oxalic acid leach, some of the silver drops to the bottom of beaker and the rest need to be sprayed out with water. It removes instantly. Awesome method this is.

One film produced 0.52 grams of gray silver precipitant. I am processing another film to make it to 1 gram to be melted and post photos.

Regards,
Kevin

 

[goldsilverpro]

Manuel has stated that the oxalic acid dissolves the emulsion but, from the high numbers you're getting, I think there is still some emulsion mixed with the silver powder. I think it would be wise to incinerate it to a white ash before melting it.

 

[kjavanb123]

All,

Finally some numbers on my silver recovery from x-ray using oxalic acid leach project.

Total weigh of films: 204 grams
Total gray/black precipitant: 2.14 grams
Silver ( metal ) produced from melting the gray precipitant : 0.760 grams
Unknown ( slag ) from melting the gray sludge : 1.19 grams.

Conclusion, the gray residue coming down from the films during the oxalic acid leach is not all pure silver, so from number above;

(0.760 x 100 ) / 204 = 0.37% of the gray residue from the oxalic acid leach is silver metal

Note: this batch of 204 grams of films seem to be same size and similar picture of a chest, so next batch i am going to try a 1 kg and post results.

So GSP is the man on this subject, incineration would required after the gray sludge is dried.

Thanks and regards,
Kevin

 

[goldsilverpro]

kjavanb123,

Your yield of .764 grams is about 54% of what I would expect from average developed rare earth film. Chest shots always contain less than the average, but that still seems a little low. However, when dealing with such a small amount of silver, it's hard not to lose traces here and there in the process.

 

[kjavanb123]

GSP,

Thanks for your comment. I have finally got the silver purity, it is 96% pure. Here are some photos of the silver recover and melted, and the slag from melting the gray powder which I thought would be all silver.

Silver recovered from x-ray films.


Slag from melting the gray powder precipitated from x-ray leach in oxalic acid.


Any ideas what the slag is?? emulsion? should I change the oxalic acid ration from 5% to 3%? that way the slags don't come down with silver?

Also, as I am trying to leach 8 similar chest x-ray films, I have to cut them into small pieces in order to fit inside 1-liter beaker, and I noticed if I heat the oxalic acid solution up to boiling, it would expedite the extraction, but the same oxalic acid solution I started stopped working after processing 4-5 films in it. So re-use of acid has limits.


Regards,
Kevin

 

[kjavanb123]

All,

Once read on this post, that silver refiners use paper shredder to cut the x-ray films into smaller pieces then dissolve in oxalic acid leach, this method would cut the oxalic costs. One thing I don't get is once shredded films are leached the gray/black powder from them are mixed with the shredded films, how do they get separated?

Regards,
Kevin

 

[nickvc]

Kevin this is Manuel,s method and if I remember correctly for the oxalic to work properly it has to be 95 degrees for it to work. The film that's shredded needs to be moved around the in the solution so a stainless sieve or container with many holes in from a caterers to dunk the film in and out of the solution helps and then rinse off to reclaim any trapped silver in a separate container. The good news is that the solution is easily disposed of but only works for a specific amount of times.

 

[kjavanb123]

All,

Wow it has been over 6 years since my last post in this thread. Time flies.

Today I processed 1.1 kg of MRI scan films and a chest film. Using method described by Manuel in his thread on using lye and ethonol alcohol.

Since this was my very first try with lye and alcohol for x-ray films, I decided to cut a small piece from an MRI film and chest film.

A sample piece from chest film,


A piece of MRI scan film. This is a Dryview type x-ray film.


I squeezed the samples in my hand to make them not stick together in lye solution but once in the solution they turned to flat shape.

I used GoldSilverPro advise on using 100g lye with 1000 ml of tap water, let it boil after I put the samples in.

As discussed here, chest x-ray film sample was clean in first minute into lye solution, but MRI scan film sample did not change.

Per Manuel advise I cautiously added 10ml of ethonol alcohol, and after about 20 minutes random agitation and addition of alcohol I investigated MRI film sample and it looked like this,


The black emulsion was not completely off so I used another spoon to peel it off.

I have to thank Manuel and GSP for providing the formula to do this.

Couple of questions that I will try to experiment and find the answer, one would be does dryview film requires longer time in solution and more agitation? Also how much ethonol alchohol to be uaed per 100g of lye dissolved in 1000ml of tab water?

I was cautious so I added alcohol in 10ml increment.

Here is the final shot of cleared films.

Best regards
Kj

 

[goldsilverpro]

The silver on film is probably 99.99% pure and it will stay that way unless you contaminate it. The only exception I know of is that some litho film has a little tin in it.

 

[kjavanb123]

GoldSilverPro

Thanks. I prepared a solution based on your 100g/l lye and water. It had 7000ml tap water and 700g of lye.

Cut the large CAT scan films into 4 pieces and dropped them one by one into the solution.

Brought it to 90s degree, and added 100ml of ethanol alcohol, stirred few times and let the films in lye solution for 1.5 hrs.

After that most of black/silver layer on films could easily peeled off as it can be seen below.


I think more ethanol needed so I will buy another 100ml and add to near boiling lye solution so the rest of the films are stripped.

Then will be incineration of stripped materials and smelting with borax and soda ash.

Will post how much ethanol was used for 7000ml lye solution as I could not find the amount posted in Manuels threads.

Best
KJ

 

[kjavanb123]

Updates,

I noticed there was a type of film which solution did not touch at all. Could this be a digital type film?


Here are the silver bearing films so far.


Thanks and regards
Kj