# X-ray for gas companies



## kjavanb123 (Feb 21, 2016)

Hi,

My scrapper is attending an auction to buy one metric ton of these x-ray films that gas companies use to scan the pipes or similar stuff for any leakage. Anyone ever processed them? Yields?

He gave me small sample, it weighs 3.1g as can seen in this photo,



The sample xray film in the "taboo" solution , it took 10ml of hydrogen peroxide and it dissolved all the silver,



After percipitating silver as silver chloride you notice very small amount of it.



Unlike medical x-ray films that you can see a lot of spots that has no silver this type is dark brown almost all of it. Please advise


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## goldsilverpro (Feb 21, 2016)

In the first (lousy) photo, the black sheet looks like regular developed industrial x-ray film. If so, it should average between 17 and 22 grams of silver per kilo, assuming you can see through the film, somewhat, but only with a very strong light on the other side.

H2O2 doesn't dissolve silver.


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## kjavanb123 (Feb 21, 2016)

Good evening Sir, 

Thanks for your response. I meant added hydrogen peroxide to the cyanide solution I have prepared to dissolve the silver layer on the film.

Sorry for the photo, but it looks more dark brown and these films are used by a gas company for pipeline inspection. I presume, for the quantity we will have which is around one metric ton, pyrolyzing them then smelting would be the fastest way to recover silver.

Best
Kj


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## etack (Feb 22, 2016)

kjavanb123 said:


> Good evening Sir,
> 
> Thanks for your response. I meant added hydrogen peroxide to the cyanide solution I have prepared to dissolve the silver layer on the film.
> 
> ...



http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=11047&hilit=xray+gsp

Eric


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## goldsilverpro (Feb 22, 2016)

kjavanb123 said:


> Good evening Sir,
> 
> Thanks for your response. I meant added hydrogen peroxide to the cyanide solution I have prepared to dissolve the silver layer on the film.
> 
> ...


Kevin,

*You cannot precipitate silver chloride from a CN solution.* CN actually will dissolve solid silver chloride.

Until 1983, Room temp Cyanide + H2O2 was the standard (and best) industrial method used for x-ray and litho film. They simply plated the silver out and reused the solution. In 1983, a plant worker in Chicago died and ithe media ran with it. 60 minutes had an episode on it. The industry stopped using CN and switched mainly to NaOH.

I've never used CN on film. I would imagine that the H2O2 would have to be tightly controlled and kept at a minimum, for 2 reasons. (1) H2O2 will decompose CN. (2) H2O2 will impede the plating of silver.

With open burning of film, you will lose 25-30% of the silver into the air, according to Kodak. I would imagine you would lose something with pyrolysis and smelting.


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## rickbb (Feb 22, 2016)

The NaOH method works well, no need to risk death with CN or pollute the air by burning all that plastic.

With a ton to process you will need large tanks or vats and they need to be heated, hotter works better but not boiling. A hot vat to strip the film in and a couple more to rinse it in.

A perforated plastic barrel and a way to keep it rotating in the bath to prevent the films from sticking to each other.


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## kjavanb123 (Feb 22, 2016)

Dear All,

Thanks for your comments. I wanted to test this tiny sample, so prepared a cyanide solution and it clearly dissolved all silver with small addition of peroxide. I then checked pH to be 11, added zinc powder and washed the residue with hot water 3 times, then covered zinc powder with water, added nitric acid, until all dissolved, added hcl to that solution and that percipitated very tiny amount of silver chloride.

Cyanide leach on this sample was quiet fast, so if we do it safely it would be nice. On that note pyrolyze them in a closed reactor would still lose that much silver?

Regards
Kj


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## goldsilverpro (Feb 22, 2016)

If you haven't run film before, chemically, you will quickly learn that the film will have to be first chopped into small pieces, if you want to get any production out. If you put full sheets into any liquid, the emulsion gets sticky, the sheets stick together, and the solution can only penetrate from the edges, very slowly. Even with tumbling, full sheets can take hours. 

A heavy-duty paper shredder will cut, tear, and twist the film, thus eliminating the sticking-together problem. However, since the film gets distorted, it occupies more space - as much as 10 to 20 times more than chopping it into small flat 1/2" pieces with a rotating shear (plastic granulator). The blades on these look like those in the photo.
http://www.thebladespecialist.com/plastic-machine-knives/
The units look like this (cutaway views from the side). They're not cheap.
http://www.ptonline.com/articles/avoid-four-common-traps-in-granulation

Trying to feed the sheets through the solution one at a time is a fool's errand. Industrial x-ray sheets are relatively small and usually have 40, or more, sheets per pound. If that 3.1g sample you have is representative of what you'll get, you're talking 146 sheets per pound. If it runs .25 to .3 oz Ag per pound of film (a guess), that's only 2.5 to 3 cents per sheet. Your metric ton would have 327,000 sheets.

I should note that the value of this film is still a mystery.

To me, film is a lo-value, hi-volume business. In any chemical method for film, you must have the equipment to do it right and make money. I would consider a ton as much too small an amount to get excited about. Without the right equipment, you could spend the rest of your life screwing around with a ton of it (about 2 gaylords packed fairly tight). Personally, considering the situation, I would probably turn the job down - unless I could get it for free.

However, since it's a one-shot deal, pyrolysis or burning gets more attractive.


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## kjavanb123 (Feb 22, 2016)

Thank you Chris. As always excellent information. I never did large batches of films, so this is the first. The scrapper already purchased this lot and is being delieverd on Saturday. 

I would rather to do it using smelting. Once arrived in my shop, I will take a lb similar sample, and test them using methods you mentioned here. 

Regards
Kj


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## nickvc (Feb 23, 2016)

Kevin have you thought about using Manuels dilute hot oxalic acid method, no burning, no chlorides, no conversions and very fast, just silver easy to clean and melt.


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## kjavanb123 (Feb 23, 2016)

Nickvc,

I tried oxalic acid method on few films few years ago, but with volume we are expecting, is going to be very messy. I am leaning toward pyrolysis then smelt. 

Regards
Kj


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## Lou (Feb 23, 2016)

Well don't forget the PET is probably 15-20 cents/lb in truckload quantities.

Cyanide is arguably the best way to do rare earth/industrial (even behenate) film period end of story. Unfortunately, even though the solutions are dilute, and everything can be made quite safe, getting permitted to use it might be a bit of a challenge.


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## goldsilverpro (Feb 23, 2016)

If you don't eat it, drink it, add acid to it, or swim in it, cyanide is a very safe chemical. Far safer than strong H2SO4, HNO3, NaOH, or HCl.

I know a guy that fell into a vat of cyanide film stripping solution. He was completely immersed and lived to tell about it. Try that with any of those other chemicals. And you can destroy it when you're finished with it.


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## Lou (Feb 24, 2016)

We're on the same page.

It's great stuff, managed and used responsibly.


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## nickvc (Feb 24, 2016)

I think both Lou and Chris know I agree completely.
I hesitate to promote its use for the simple fact that many cannot or will not bother to learn how to do many processes promoted here that are relatively safe and to promote a chemical which I agree is safer than many but will kill if not handled properly, I'm not to sure I want that worry.
When I see the messes many get in with simple well explained processes the thought of promoting its use terrifies me in honesty, it's certainly not a back yard job where kids, pets, friends, neighbours and who knows who else can mess with, the fact that many cannot smell it is one concern that acids don't carry is one huge factor to make me concerned.
In the right hands and with the right knowledge it's tough to beat but I wouldn't help anyone who I didn't know had enough knowledge and sense to use it without damaging anything or anybody including themselves.


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## goldsilverpro (Feb 24, 2016)

I knew a guy that had about a 25 pound dried out cyanide crust in the bottom of a large but shallow tank. He put the tank outdoors inside a small area enclosed with chain link fencing to keep the farm animals out and covered the tank with a sheet of old plywood. After a year or so, the plywood got some holes in it from rot and the tank started filling with rain water. When it eventually got full, it overflowed and drained some liquid to the outside of the fence. Two prime bulls, used for raising rodeo bulls, ate or drank some and didn't get 10 feet away from the fence before they died.


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## nickvc (Feb 24, 2016)

goldsilverpro said:


> I knew a guy that had about a 25 pound dried out cyanide crust in the bottom of a large but shallow tank. He put the tank outdoors inside a small area enclosed with chain link fencing to keep the farm animals out and covered the tank with a sheet of old plywood. After a year or so, the plywood got some holes in it from rot and the tank started filling with rain water. When it eventually got full, it overflowed and drained some liquid to the outside of the fence. Two prime bulls, used for raising rodeo bulls, ate or drank some and didn't get 10 feet away from the fence before they died.




You more than obviously understand my point Chris 8)


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## kjavanb123 (Feb 25, 2016)

I have used cyanide a lot of times, thanks to members like GoldSilverPro and others, and it is the greatest tools and have been very safe. I always use hydrogen peroxide to destroy cyanide solution it turns brown in color when enough peroxide is added, I keep this solution in bucket to get my OEM meter to see if it is safe to dump it.

Regards
Kj


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## Lou (Feb 25, 2016)

It's never safe to dump it if you've just treated with peroxide unless you've done the proper testing. Just be advised that while peroxide helps it does not de-list the material here in the United States.

When we used to use CN to strip gold plated parts, we would chemically oxidize it but it still remained residually hazardous per the law, even if I could take a gallon of it, add a liter of sulfuric to the treated stuff and stand over the beaker!


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## Juan Manuel Arcos Frank (Feb 26, 2016)

Hey,Kjavanb123....How about sodium hypochlorite process?...it is fast,safe,cheap,room temperature working and an easy way to make money with those X ray industrial films.

I have posted the process and a patent here in the Forum,take a look.

Kindest regards.

Manuel


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## Ubongrex (Jul 7, 2016)

Yeah I agree with manuel sodium hypochlorite method might just be what you are looking for... It's cool. Much respect to Goldsilverpro... 

Manuel it's been a while

Rex


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