# Silver from xray flim



## sena

Hi need help in recovering silver from xray flim , i have recovered silver using nitric leaching , the problem is while melting the converted chlorides , any alternate method please help, secondly how "fixer solution " is made? 

Regards 
Sena


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## Lino1406

Dip the film(s) in soda caustic solution, one
by one, that will clean them of the silver.
If enough innovative you can build a mechanism 
similar to suspending laundry


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## sena

Lino1406 said:


> Dip the film(s) in soda caustic solution, one
> by one, that will clean them of the silver.
> If enough innovative you can build a mechanism
> similar to suspending laundry


 thanks for the information , i ll go for a trial tommorow.


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## sena

Yes , the caustic solution removed every bit of the emulsion , i need to know the settled sludge is silver , and the solution is still dark , how come we know that the solution is free from silver?...


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## Juan Manuel Arcos Frank

Silver is not pure because the mud contains gelatine rests,NaOH and silver.The only method which obtains pure silver directly is oxalic acid method,the process,step by step,is posted in this wonderful Forum.

Kindest regards.

Manuel


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## goldsilverpro

sena said:


> Yes , the caustic solution removed every bit of the emulsion , i need to know the settled sludge is silver , and the solution is still dark , how come we know that the solution is free from silver?...



In my experience, the NaOH doesn't alter the silver compound on the Dryview, silver behenate. It breaks down the emulsion and the silver behenate breaks up and forms fine black particles, which are very slow to settle and difficult to filter. In production, we always ran everything through a big filter press.

What sayeth you, Manuel. For Dryview, didn't you once suggest adding ethyl alcohol to the NaOH? What does the alcohol do? Any dangers in doing that? Can the alcohol be added at this point? If so, how much? If so, will a cheaper alcohol, such as isopropyl or methanol work as well?


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## Juan Manuel Arcos Frank

GSP,My Dear Friend:

You have such a nice memory!!!!!!,Yes,Sir,I said that about processing DryView films,alcohol makes emulsion easier to fall out,I think that emulsion in DryView films is different from emulsion in silver halide films,DryView films are developed by heat.

Ethyl alcohol(cheaper than isopropyl or methanol) could be used with good results,the process consists in dipping the films in a hot(60 C) solution of caustic soda,then add some ethyl alcohol and shake a little bit,the emulsion(with silver behenate) falls down nicely,pour off the solution,filter the solid and process it with the known methods.No one danger observed.DryView films contain very little silver.

Somewhere in my computer I have the process,step by step,I promise to post it ASAP.

Chris,behave yourself.Have a nice day.

Your friend:

Manuel


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## sena

what about neutrlizing the solution with hcl?, i think we may get the sedimentation quicker .


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## chandler_P

Hi Manuel/GSP,

I am new here and new to silver recovery. Could you tell me a step by step guide on the recovery of silver using caustic soda?

All the best,

chandler_P


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## Juan Manuel Arcos Frank

As I promised,here is the process to recover silver from DryView film.
---------------------------------------------------------------------------------------
Sena:

Recovering silver from films using nitric acid leaching is not a good idea,there are better and cheaper processes to make the same job,in example,NaOH process,oxalic acid process or iron chloride process.
--------------------------------------------------------------------------------------------

Chandler_P:

Being present GSP,it would be a daring from me to talk about NaOH process...ask GSP.
---------------------------------------------------------------------------------------------------------------------- 

Kindest regards to all of you.

Manuel


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## seawolf

I found this on recyclebiz.com.
"There are many processes for silver recovery from B/W films, offset negatives and radiographies. Combustion of film, nitric acid leaching, caustic soda leaching and CLOROX treatment have been proposed in this forum. Except combustion, all of them produce a silver intermediate compound that needs more processing to obtain pure silver, besides, all these processes release toxic fumes to the environment and nitric acid leaching and caustic soda leaching can cause severe burns.

The new process uses a low concentration of oxalic acid to attack the gelatine of the film and the silver goes down as a grey/black mud that only needs drying and melting to obtain pure silver. Concentrated oxalic acid is poisonous, please, use NIOSH/MSHA approved respirator, NIOSH approved gloves, splash goggles for eye protection and wear appropriate clothing to prevent skin exposure. Read MSDS for oxalic acid before start the process.

The process is quite simple, just make a 5%(weight or volume) solution of oxalic acid in tap water, heat this solution to 95 C, then submerge the films in the acid solution, in 20 minutes all the silver is removed. Once that all silver has been removed rinse the films and let them dry, you can sell the plastic base to a plastic scrap dealer.

Let the mud settle down, pour off the liquid solution, dry the mud and melt it, you will get 0.999 silver." 

This might be an easier way to go. I have seen the oxaclic acid method mentioned several times but I could not find it with the search box. If there are other or better posts please post a link to them.
Mark


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## nickvc

Manuel posted this process many years ago...if you want to know about silver it's either GSP or Manuel on here.


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## Juan Manuel Arcos Frank

INDEED!!!!!...I posted that a few years ago...Do guys from recyclebiz.com say that this information comes from Gold Refining Forum?


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## seawolf

Juan Manuel Arcos Frank: I did not see anything about who first posted this. I did a Google search for the process and it came up. I copied it and gave the source in my post as I think it should be. I have tried to find the information on the GRF but without much luck. I do not wish to step on any toes or ruffle anyone. I only posted it in response to an existing post to try to help and I did ask for more input from others with more knowledge.
Mark
Below is the full post and yes it is accredited to the GRF and Juan Manuel Arcos Frank.

Re: X.ray films scrap
by Chris Owen » Sat Jun 12, 2010 7:21 am 

The quote below is from goldrefiningforum.com. I have never used this method but it is claimed to work well. Keep the oxalic solution weak (the info below uses a 50 g/l solution) because if it is stronger, it is said that it might create sodium oxalate, which is explosive, although I have no idea where the sodium ion is coming from. Use a respirator and gloves when handling the oxalic acid powder, as it is toxic. After the solution is made up, it is supposedly not necessary to use a respirator. Also, it is said that the solution can be reused.

I have used about 4% sodium hydroxide for 1 hour at about 95C in an 40,000#/day film operation. Also, 10% sodium hydroxide, at about 60C or a bit less, will strip the film in about 10-15 min, although using it is more dangerous to use than the weaker solution. I have also used a proprietary enzyme/sodium bicarbonate solution, at about 40C, that will strip in about 10-15 minutes - this is about the safest solution to use although, since it ferments the emulsion, it really stinks. The problem with all these solutions is that the emulsion that is removed along with the silver must be incinerated before the silver is melted. Supposedly, this incineration isn't necessary with the oxalic acid solution.

No matter what chemical process is used, the films should be shredded before stripping, in order to get complete stripping and to keep the stripping time at an acceptable level. Unshredded films stick together when wet and this prevents the solution from getting in between them. I have seen both paper shredders and tree limb shredders used, but both tend to twist the film pieces and this reduces the bulk density tremendously. The best shredder is one that shears or cuts the film to 1/2", or smaller. That way, the pieces lay flat and you can get a lot more film in the tank. It is also better to use a tumbler. I once made one from a stainless tumbler out of an old clothes dryer that held about 150 pounds of film.

"There are many processes for silver recovery from B/W films,offset negatives and radiographies.Combustion of film,nitric acid leaching,caustic soda leaching and CLOROX treatment have been proposed in this forum.Except combustion,all of them produce a silver intermediate compound that needs more processing to obtain pure silver,besides,all these processes release toxic fumes to the environment and nitric acid leaching and caustic soda leaching can cause severe burns.

The new process uses a low concentration of oxalic acid to attack the gelatine of the film and the silver goes down as a grey/black mud that only needs drying and melting to obtain pure silver.Concentrated oxalic acid is poisonous,please,use NIOSH/MSHA approved respirator,NIOSH approved gloves,splash goggles for eye protection and wear appropriate clothing to prevent skin exposure. Read MSDS for oxalic acid before start the process.

The process is quite simple,just make a 5%(weight or volumen) solution of oxalic acid in tap water,heat this solution to 95 C,then submerge the films in the acid solution,in 20 minutes all the silver is removed.Once that all silver has been removed rinse the films and let them dry,you can sell the plastic base to a plastic scrap dealer.

Let the mud settle down,pour off the liquid solution,dry the mud and melt it,you will get 0.999 silver." Juan Manuel Arcos Frank, author


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## goldsilverpro

I think I'm in deep s**t.


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## Juan Manuel Arcos Frank

Seawolf:

Nothing has happened here...All information posted in internet is free available.

I send you a big hug.

Kindest regards.

Manuel


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## Juan Manuel Arcos Frank

GSP,My Dear Friend:

LOL!!!!!....No way!!!!!....All what is mine is yours!!!!!

Let us forget this minor incident and let us continue drinking whisky.

Have a nice day.

Your friend:

Manuel


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## chandler_P

sena said:


> what about neutrlizing the solution with hcl?, i think we may get the sedimentation quicker .



yup, this could be done but what does it release, i mean, does this release some chlorine gas? unsafe, but yes it's quicker to settle the silver by adding HCl. I tried it already bit not quite sure of the chemistry or safety of this.
let's ask for other members about this, i'm also in search for this, if it does result to emitting chlorine gas.


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## mda20

Dear kind members,

Good day. 

I have tried the oxalic acid process but I have not get any result!

The process was;
500 gm of Oxalic Acid added to 10L tap water.
solution heated to about 90C.
3 kg of films submerged in the acid solution.

The result:
nothing happened. Films still black, no reaction.

Please tell my what is my mistake?


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## nickvc

Mda20 you have to get it up to at least 95C, and it must be 5% by weight oxalic acid and the film needs to be in the acid for 20 minutes with I would have thought some movement to make sure all the silver drops out. Manuel really is the man to answer these points accurately but I think I have his process right.


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## Juan Manuel Arcos Frank

No way!!!!!!...Nickvc has answered masterfully!!!!!!.

Let us take a look to the films.Are they silver halide type or silver behenate type?,let us find out:Take some bleach(like CLOROX) and dip one of those films in it...if black stain goes away then they are silver halide type and the problem seems to be low temperature(as Nickvc has well stated),if black stain remains then films are silver behenate and this is the reason that oxalic acid process does not work,besides,silver behenate films type contains less than 1 gr of silver/kilo.

Nda20,where do you live?

Nickvc,I send you a big hug.

Kindest regards.

Manuel


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## mda20

Thank you* Nickvc* and *Manuel*

The films are silver halide types. I have checked this by clorox. When I dipped one of that films in clorox bleach, the black stain gone away.

By the way, I used steel container to heat the oxalic solution, is that wrong?

I will repeat the process with increasing the temperature.


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## mda20

I have repeated the process with increasing the temperature as Nickvc said. I have succeeded.

But how long I have to wait for settle down the mud? It looks very slow!


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## Juan Manuel Arcos Frank

A colloid has been formed,probably due to organic contamination,the mud should precipitate pretty soon,anyway,you have got to destroy the colloid by boiling the solution for half an hour.

Take a look at your original films before processing,they must be perfectly clean,if it is necesary then make a prewash with tap water.

Keep us posted about your progress.

Kindest regards.

Manuel


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## mda20

Thank you Manuel

The films are clean. But may be the contamination occurred because I re-heated the solution and submerged the same films. 

Other thing I have to say is that I used steel container for heating!

My best regards


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## sena

please post some pic of your x ray scrap...


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## mda20

Here are pics for some of my x-ray films.




sena said:


> please post some pic of your x ray scrap...


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## sena

Good picture brother , for me i was processing using NAOH process , but i was dealing with industrial x ray flim , if u go through my post you may have a look at it, as for me , naoh process is quite easy for me as there is no need for heating the solution all you do it in a couple of hours ( depends upon the quantity ), try for one film with a spoon of naoh and half or 1 litre water , see that gelatin the layer removes it should ,


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## mda20

Thank you Sena

I tried the caustic soda process long time ago. The problem with that process is the melting. 

I get difficulty to melt the sludge. Therefor I stopped that process.


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## sena

mda20 said:


> Thank you Sena
> 
> I tried the caustic soda process long time ago. The problem with that process is the melting.
> 
> I get difficulty to melt the sludge. Therefor I stopped that process.



Dear friend have you incinerated the sludge before melting ?


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## mda20

Yes dear friend. After filtering the material, the silver compound was heated in an iron vessel until all the gases were removed. Then taken to melting.


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## sena

mda20 said:


> Yes dear friend. After filtering the material, the silver compound was heated in an iron vessel until all the gases were removed. Then taken to melting.



it should look like this after incinerating...


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## mda20

No, what I got was black in color.


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## mda20

To my friends Manuel and Nickvc,

I would like to inform you that the sludge has been settled now. I have not done any thing, just waited.

Now I will go to dry step. Is it good to put it under the sun?

My regards.


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## goldsilverpro

mda20 said:


> No, what I got was black in color.



It sounds like the difference is that you just heated it to drive off the gases (leaving black carbon in the material) whereas Sena incinerated it and burned out all of the organics/carbon to a white ash. Huge difference. In my experience, it should be incinerated before melting. You must get rid of the carbon first.


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## mda20

Thank you goldsilverpro.

My aim is to dry the sludge, so the result is black powder.


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## goldsilverpro

mda20 said:


> Thank you goldsilverpro.
> 
> My aim is to dry the sludge, so the result is black powder.



Have you tried melting the black powder? If so, does it give you better results than direct melting the sludge? I think the melting would go even smoother and you would get better yields by incinerating to white ash before melting. Otherwise, the black carbon will pick up silver and will tend to float on top of the melt. You will also likely end up with more silver BBs in the slag.


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## mda20

Actually I get difficulty in melting because I have to add the following:
Sodium Nitrate %100
Borax %50
Soda Ash %25

Sometimes I succeed but mostly the crucible was damaged.


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## sena

mda20 said:


> Actually I get difficulty in melting because I have to add the following:
> Sodium Nitrate %100
> Borax %50
> Soda Ash %25
> 
> Sometimes I succeed but mostly the crucible was damaged.



I use generally equal volume of Borax to that Incinerated Silver sludge, with oxy acetylene torch .its easy to melt reduces the heat consumed swell as the time.


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## goldsilverpro

mda20 said:


> Actually I get difficulty in melting because I have to add the following:
> Sodium Nitrate %100
> Borax %50
> Soda Ash %25
> 
> Sometimes I succeed but mostly the crucible was damaged.



The sodium nitrate is needed to oxidize the carbon but this reaction destroys crucibles. If you were to incinerate to white ash (no black) before melting, as Sena has done, you wouldn't need any sodium nitrate, at all, and, therefore, you wouldn't damage the crucible nearly as much. You could also, probably, cut down on the borax and soda ash. The only purpose of the soda ash is to convert any silver halides to silver metal. This reaction can also damage the crucible, somewhat, but, if you are stripping with sodium hydroxide, any silver halides should already be converted to silver oxide, which will be converted to silver metal by the heat alone. However, just in case there are still some silver halides still present, I prefer to add some soda ash. If you were to incinerate to a white ash before melting, I would first try a flux mixture of about 25% borax and 5 to 10% soda ash. It is always best to thoroughly blend the flux with the pulverized incinerated white ash before melting.

If you are stripping with bleach or 10% HCl, you end up with 100% silver chloride and this will require lots of soda ash to convert it to silver metal and, in the best case, you possibly won't get it all converted. In large quantities, this reaction will destroy crucibles very quickly. Probably, of all the various ways to strip film, any method using chlorine or chlorides is the worst. It strips quickly with no heat, but you definitely will pay the piper down the line.

If you are using oxalic acid, as in Manuel's process, I would ask him as to how to flux it. I would guess that all it would take is some borax and, maybe, a little soda ash, just to make sure.


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## mda20

goldsilverpro said:


> mda20 said:
> 
> 
> 
> Actually I get difficulty in melting because I have to add the following:
> Sodium Nitrate %100
> Borax %50
> Soda Ash %25
> 
> Sometimes I succeed but mostly the crucible was damaged.
> 
> 
> 
> 
> The sodium nitrate is needed to oxidize the carbon but this reaction destroys crucibles. *If you were to incinerate to white ash (no black) before melting, as Sena has done, you wouldn't need any sodium nitrate, at all, and, therefore, you wouldn't damage the crucible nearly as much.
> *
Click to expand...


Thank you goldsilverpro for these precious info.

I heat the sludge hardly to red hot temperature, but the result is black powder not white!


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## goldsilverpro

I just reread the thread and found that you are using oxalic acid. I have never used it. Maybe Manuel will respond.


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## mda20

It is the first time I use oxalic acid. I have gotten this from Manuel and so far the process not finish because I have to dry the sludge. In this way I wonder if drying under the sun is enough?

Regarding to caustic soda process, if I go to this process, I will try your process and Sena`s process in melting.

Thanks to you GSP and to Sena.


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## mda20

Dear Manuel,

Good day.

Regarding to oxalic acid process, now the silver compound is dry ( It has been dried under the sun).

Shall I add any chemicals with melting?

Regards


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## Juan Manuel Arcos Frank

mda20:

I offer an apology because I was in Mexico City doing some business and I could not answer you soon.

Look,oxalic process yields to pure silver,there is not need of any flux...anyway...if you are not getting metalic silver from your black sludge then you can use some potassium nitrate(saltpetre) as flux,melt the black sludge with its same weight of saltpetre,when it is liquid add a pinch of saltpetre until you get metalic and white silver.

Look at your process,there is some contamination that is causing you problems.

Would you mind to tell me,step by step,all you have done?

Kindest regards.

Manuel


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## goldsilverpro

Juan Manuel Arcos Frank said:


> mda20:
> 
> I offer an apology because I was in Mexico City doing some business and I could not answer you soon.
> 
> Look,oxalic process yields to pure silver,there is not need of any flux...anyway...if you are not getting metalic silver from your black sludge then you can use some potassium nitrate(saltpetre) as flux,melt the black sludge with its same weight of saltpetre,when it is liquid add a pinch of saltpetre until you get metalic and white silver.
> 
> Look at your process,there is some contamination that is causing you problems.
> 
> Would you mind to tell me,step by step,all you have done?
> 
> Kindest regards.
> 
> Manuel


He's using sodium nitrate and it's chewing up his crucible. How would potassium nitrate be any different?


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## mda20

Thank you dear Manuel and welcome back.

The process was:
-500 gm of Oxalic Acid added to 10L tap water.
-Solution heated to about 90C in steel container.
-3 kg of films submerged in the acid solution.

The result:
Nothing happened. Films still black, no reaction.

The process is repeated as the following:
-The films were removed from the solution.
-The solution is re-heated to higher temperature.
-The same films were re-submerged in the solution.
-The black stain was removed by ribbing.
-After 3 days the sludge settled down.
-Sludge collected and dried under the sun.

The result is black power as in the picture.

Best Regards.


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## sena

whats the weight ?


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## Juan Manuel Arcos Frank

GSP,My Dear Friend:

There is no difference between using NaNO3 or KNO3,the difference consists in adding the flux once the contaminated silver is liquid,the reaction that takes place whitens the silver.

Crucibles have to be cured,here is how I cure them:

Dip the original crucible in tap water for a few seconds.
Pick up the crucible and put it upside down
Heat the crucible with the torch for a while
Put the crucible upside up and add some dehydrated Borax
Melt borax and cover all the crucible with a liquid glass film
The crucible is ready 

Of course,crucibles do not last lifetime but they work better if they are cured

Have a nice day

Your friend:
Manuel


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## Juan Manuel Arcos Frank

mda20:

Black powder seems to be OK,let us take a look to the vessel,What kind of stainless steels is?


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## mda20

Here is the steel container.

The black power is about 30 gm.


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## Juan Manuel Arcos Frank

GREAT HEAVENS!!!!!!!!!!!!...that pileup is not made with 316 stainless steel!!!!.

This is the source of all your problems because it is dissolving slowly(and forming an iron salt that could form a colloidal solution).Oxalic acid solution are used as rust remover.You must change your vessel,get a 316 type one.

Now,the black mud could contain some iron salts,melt it and make shot,process it(for this time) with Karo syrup process or nails process to obtain your silver.

As soon as you use a 316 SS vessel you will get pure silver without any problem.

Keep us posted about your progress.

Kindest regards.

Manuel


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## mda20

Thank you very much Manuel.

Is there an other choice of vessel? I mean can I use an other metal or glass vessel instead of stainless steel?


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## Juan Manuel Arcos Frank

Yes,Sir...you can use PYREX glass.

If you buy a new 316 vessel then it would be very expensive,but you can get an used one very cheap.

Check in junky yards,look for an old photo processor or an old X Ray processor,they are made with 316 stainless steel.I have never tried aluminium,make a test,process a few films in an aluminum vessel and see what happens.

Keep us posted about your progress.

Kindest regards.

Manuel


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## Lou

Don't use aluminum! It reacts with caustic (or oxalic acid) to produce hydrogen gas!


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## mda20

Thank you *Manuel *for your help.

I will repeat the process and let you know what will happen.

To Lou:
Thank you for your advice. I will not use Aluminum.

Best Regards,
MDA20


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## Juan Manuel Arcos Frank

Thanks,Lou!!!!!
Kindest regards.
Manuel


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## A_mitra

The process was:
500 gm of Oxalic Acid added to 10L tap water. 
solution heated to about 90C. And scrub and got mud. 
Now melting prossage: I have a great problem. 
Heat coal Add mud to a iron container, add borax/Na2CO3/CaCO3 step by steep but after ½ hour it was very har.

I need your kind help step by step mathods and how much gram borax/Na2CO3/CaCO3 will add. 
Like i add mud in to the iron container then heat then add borax/Na2CO3/CaCO3.
When I will add. I tried many itmes but I am unable to do. 

I am keenly requested t solve my problem.

Thanks
Previous


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## Juan Manuel Arcos Frank

A-mitra:

Not that fast...first of all you have to heat oxalic solution and films to 95 C for 20 minutes,at least.If you heat to 90 C chemical reaction between oxalic and gelatine does not take place.

To melt silver you need to reach 1000 C,so you need an oxygen/propane torch or a convection oven.

You do not need any flux but if you want to use any then use potassium nitrate.

Kindest regards.

Manuel


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## kjavanb123

Hi,

Does oxalic acid method work on both types of x-ray films? Halide. And other type? Because, I have tried this method on a MRI type of films and nothing happened.

Thanks
Kevin


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## kjavanb123

All,

Just an update on silver recovery from x-ray films using the methods described in this thread. Once it cleared the films out and you can see a blue color film, silver is a silvery deposit at the bottom of beaker. I have tried 2 films so far, one weighed 18.74 grams, and I could get 0.20 grams of silver from it, I am going to come up with surface area / gram silver ratio for each films.

Juan,
Once the silver is at the bottom of beaker, if i decant some of the particles goes back to the top of surface and would go to the bucket, do you suggest filtering the silver powder? Doesn't it get stock to the filter paper?

Regards,
Kevin


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## goldaa

plane old chlorox strips film wonderful then filter the mud and melt with sodaash.


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## gunhawrtis

Any one knows how to recover silver from film using hydrogen peroxide method?


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## Smack

hydrogen peroxide method? Never heard that one.


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## sena

gunhawrtis said:


> Any one knows how to recover silver from film using hydrogen peroxide method?


Hi gunhawartis, there are standard methods that are simple and less chemicals to add while processing , when it comes to recover silver from x-ray scrap ,
you can make comfortable with these basic methods , i think peroxide (if there is process using) is not financially much cheaper than Naoh or oxallic chemicals .

Thanks
Sena


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## kjavanb123

All,

Here is another update on 2 more films.

Film 1, weighed 28.09 grams, dimensions 29 x 39 cm dry silver powder prior to melting 0.32 grams
Film 2, weighed 17.26 grams, dimensions 29 x 23 cm dry silver powder prior to melting 0.39 grams

So based on this calculation it seems average percentage for silver is %1.56 by mass. I got a hold of 12.5 kg of x-ray films, which I am going to process 1 kg of it. will post result.

I have tried oxalic acid methods on MRI type films, and nothing happened.Do they process different?

Regards,
Kevin


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## goldsilverpro

Many (but, not all) MRIs and catscans are done on Dryview or other "Dry" type film. Also, they use it for "regular" x-rays. To strip this, we used 4% caustic soda at 200F and tumbled it chopped up for an hour. Even then, a special proprietary additive, that I can't divulge, was required to get 100% of the black silver layer off of the PET plastic. I don't think that oxalic acid will touch it. Check some of the older posts by Manuel. I think he mentioned that a certain solution containing some alcohol would strip it. A big problem is that, when you get a container of film these days, it is usually a mixture of common "wet" halide rare earth film and "dry" film. When developed, these 2 types look identical (almost) and are almost impossible to sort. We did have a couple of guys that could sort it (fairly well), but they had been doing it for years. I can't sort it without checking each sheet with a cigarette lighter. I've detailed that method several times on the forum.

Since each sheet of film is different, it is a worthless exercise to base film values on running one or two sheets - an average of what to expect on various type film is the only important thing. The only exception to this is the "dry" type film. Since no silver is removed during developing, each sheet of the same size will yield exactly the same, whether developed or undeveloped, assuming it is of the same type and by the same manufacturer.

Your yields show a value of 1.56% or, .227 tr.oz. of silver/pound of film. Totally impossible unless the film is (1) of an earlier variety at least 27 years old, (2) the film was custom made (extremely unlikely), (3) it was industrial x-ray and not medical x-ray film, (4) it was 4 mil litho film, which actually looks totally different than x-ray film, or (5) Production screwed up on a batch and put on too much silver and this somehow got past QC. On this link, the included chart is based on the processing yields (and my approx. 6000 assays) of about 50 million pounds of all types of film scrap from all over the US. This chart is DEAD ON and, if you're wise, you'll accept these numbers as gospel. If you use your own figures, you'll quickly go broke.
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=34&t=3735&p=50819hilit=rare+earth+litho#p50819

Also, check this earlier thread.
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=34&t=7361&hilit=litho+chart+dryview

How do I know your numbers are way too high? If this were undeveloped (green) rare earth film, 100% of the silver would still be on it and the highest value I've ever seen is .20 oz/# (1.37%) and the average is about .18 (.123%). If it's developed rare earth film, which it probably is, the worst I've seen are chest shots, which can run as low as .065 oz/# (.45%). The best I've ever seen ran .14 oz/# (.96%) and I'm thinking that was from Sri Lanka. On average, day in and day out, it will run .10 oz/# (.69%).

I have no idea how you got such big numbers but I would guess that if you were to borax melt those powders (if they will melt) and weigh the beads, it would bring things back to reality.

Please don't take offense on what I've written, kjavanb123. I just don't want others to think this stuff is worth more than it actually is and lose money on it.


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## Palladium

All this talk about film has really got me to wanting to run some. I've never attempted it. Chris, i have about 200-300 lbs of this film that someone dropped on me awhile back for nothing. Can you tell what this stuff is? It's sort of light green and doesn't apper to have ever been used. I would like to get around to learning a little something new. :mrgreen:


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## kjavanb123

GoldSilverPro,

Thanks for your detailed response. I have read your post on films yields, but the data I posted is black/gray precipitant dry weight after oxalic leach of 2 films. I melted 0.350 grams of it and produced a silver button which is pure silver color, the rest of it melted but got stuck to the crusible, so I am not able to confirm the weight of silver metal from black powder. 
I am processing 1-kg batch of x-ray films, hope that produces enough silver powder that can be melted and will post result of before and after weight.

Also, wondering how do clean the films prior the leaching? 

Regards,
Kevin


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## goldsilverpro

> Also, wondering how do clean the films prior the leaching?



I don't understand, Kevin. Are they dirty?


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## goldsilverpro

Ralph,

Sounds and looks like undeveloped (green) rare earth film. Sort of a light lime green? If so, the silver is on there as silver halides (AgBr, AgCl). It should strip quite well in about a 8-10%, 130F, sodium hydroxide solution. This will convert the silver halides to silver oxide. Strip - settle - siphon - filter - rinse well - incinerate to white ash (stinks bad) - blend ash with borax (about 50% of the ash weight) and soda ash (about 15% of ash weight) - crucible melt - pour bar - remove slag - remelt - remove slag with warm carbon rod or rebar - pour pure clean bar. Developed rare earth film or litho film uses the exact same process.

In bulk, you almost have to chop or shred the film before stripping. If not, you run one sheet at a time or several, if you can keep them separated in the solution. If you try to run multiple sheets, they will stick together and the solution won't fully get between them

When exposed to bright light, the green film will sometimes change colors to pinkish/purplish, which causes no problems when using NaOH. 

When fully stripped, you'll have a sheet of blue (usually) clear plastic.

You can also strip green film with thiosulfate fixer but you then have to get the silver out of the solution. The best way is electrolytic with a special SS rotating drum cathode. I think some posts have been made for chemical methods, none of which I remember liking that much. One good thing about thiosulfate is that, unlike the NaOH, it only strips the silver halides and not the emulsion.


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## Palladium

Thanks Chris. Any ideas on yield?


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## goldsilverpro

Ralph,

If it is undeveloped rare earth, it will run about .18 - .20 oz/#. About $5 - $5.50/#.

The reason I keep saying "if" is because the colors in the photos look off. However, I can't think of anything else it could possibly be. Litho doesn't have rounded corners and undeveloped dryview looks like a clear sheet of blue plastic.

EDIT: Maybe you lucked out and got some undeveloped industrial x-ray film, which can run as high as .65 oz/# - $17/#. However, the Ag on that is so thick that I doubt if you can see through it as well as in your first photo. The color problem could be in your camera work. If you could just photo a few sheets spread out on a table in natural light, I might be able to tell better.


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## kjavanb123

Juan Manuel Arcos Frank said:


> GSP,My Dear Friend:
> 
> You have such a nice memory!!!!!!,Yes,Sir,I said that about processing DryView films,alcohol makes emulsion easier to fall out,I think that emulsion in DryView films is different from emulsion in silver halide films,DryView films are developed by heat.
> 
> Ethyl alcohol(cheaper than isopropyl or methanol) could be used with good results,the process consists in dipping the films in a hot(60 C) solution of caustic soda,then add some ethyl alcohol and shake a little bit,the emulsion(with silver behenate) falls down nicely,pour off the solution,filter the solid and process it with the known methods.No one danger observed.DryView films contain very little silver.
> 
> Somewhere in my computer I have the process,step by step,I promise to post it ASAP.
> 
> Chris,behave yourself.Have a nice day.
> 
> Your friend:
> 
> Manuel




Hola Manuel,

I was wondering if the same ethyl alcohol can be used with behenate films, I am using your oxalic acid leach method, and nothing happens to the films.

Thanks in advance
Kevin


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## kjavanb123

goldsilverpro said:


> Also, wondering how do clean the films prior the leaching?
> 
> 
> 
> 
> I don't understand, Kevin. Are they dirty?
Click to expand...


coming from scrap yard some of them had dirt on them, so I washed it off with hot water.


Ok here are some pictures from my silver recovery from films.

Since i haven't set up my stainless steel container yet, I cut a big film into smaller parts to hang them from a chop stick, separated by 1 cm from each other, that way they are just hung inside the beaker containing oxalic acid solution. I used 30 grams of oxalate to 600ml of water.

Since it wasn't completely submerged into the beaker part of the films still contained some silver.



Side view of the same setup



Films inside the 95c oxalic acid solution



regards,
Kevin


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## goldsilverpro

kjavanb123 said:


> Juan Manuel Arcos Frank said:
> 
> 
> 
> GSP,My Dear Friend:
> 
> You have such a nice memory!!!!!!,Yes,Sir,I said that about processing DryView films,alcohol makes emulsion easier to fall out,I think that emulsion in DryView films is different from emulsion in silver halide films,DryView films are developed by heat.
> 
> Ethyl alcohol(cheaper than isopropyl or methanol) could be used with good results,the process consists in dipping the films in a hot(60 C) solution of caustic soda,then add some ethyl alcohol and shake a little bit,the emulsion(with silver behenate) falls down nicely,pour off the solution,filter the solid and process it with the known methods.No one danger observed.DryView films contain very little silver.
> 
> Somewhere in my computer I have the process,step by step,I promise to post it ASAP.
> 
> Chris,behave yourself.Have a nice day.
> 
> Your friend:
> 
> Manuel
> 
> 
> 
> 
> 
> Hola Manuel,
> 
> I was wondering if the same ethyl alcohol can be used with behenate films, I am using your oxalic acid leach method, and nothing happens to the films.
> 
> Thanks in advance
> Kevin
Click to expand...


Kevin,

Silver Behanate film. Dryview film. Same thing.


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## kjavanb123

goldsilverpro,

I am curios why is this? film that is cut into smaller pieces are dipped into acid solution, as you can see from pictures, some of the pieces are completely cleared from silver but part of other ones are not clear completely. Any ideas?

Thanks
Kevin


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## goldsilverpro

With oxalic acid, Manuel is the expert. I've never used it. Agitation would probably help.

I'm confused. Are those small pieces rare earth film or are they Dryview?

To determine whether the film is Dryview. Hold a cigarette lighter flame under a clear (clear blue - non-black) area - it only takes a second or two. If the heated spot turns black, it is Dryview. Note that any film will turn black (burn) if you hold it long enough. Keep it brief. Another way (according to Manuel) is to put a small piece in bleach. If it doesn't strip, it's Dryview.


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## kjavanb123

goldsilverpro

I tested the films using the method you described, and except one all of them didn't change color per pointing a flame on to them on the blue area. So I assume all of the films are halide types. However, I am still confused why some of the films are partially cleared from the gray stuff. I will try to remove them using the lye method also addition of ethyl alcohol to oxalic acid leach, will post results.

Regards,
Kevin


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## Palladium

I found some markings on the box number wise and found out what it is *AGFA 10X12 Radiomat M Plus-Half Speed Blue Sensitive Fine Grain X-Ray Film*
But all i can find really is sales info.


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## 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.


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## 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


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## 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.


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## 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


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## 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.


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## 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


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## 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


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## 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.


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## 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


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## 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.


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## 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


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## 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


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