# Industrial Fixer



## Mmon2616 (Jul 3, 2014)

:mrgreen: I just want to say thanks to all that have helped lead me in the right direction on this forum and elsewhere. Last week I set up my first client and am in the process of getting the other clients ready. I am also setting up my laboratory this week. I've been so busy that I haven't had much of a chance to get to this fine forum. Once again thanks.

Some where I read about the copper wire test for fixer. It seems that the fixer I have been receiving has around 20g a liter sometimes less and sometimes a little more. My wire coated as though it was being dipped in liquid silver. I was using the zinc method so I know small amounts of zinc were contaminating. One problem I ran into with the zinc method was adding to much zinc. I read on this forum that you should put one gram of zinc per gram of silver. I found that it is way to much zinc. The best way for me was to add .37g of zinc for every gram of silver. I sent a batch of fixer to a great person that reached out to me when things got tough and he completely saturated the fix until silver chloride(or something that look similar) actually dropped out. He is now one of my business partners as well. Now I'm no chemist and I have little experience but it is what works for me. 

I am using a different method for my clients and it seems to work much more efficiently and the best part is it's cheap and it takes a few hours a month and I'm done. 

I do collect the film but it is almost a headache with everything else I have going on. My business partner helps me with that until I can find a cheap easy way to process it. 
I have some ferric chloride for the exposed film but I haven't researched it enough to use it just yet.

The reason I decided to process industrial X-ray chemicals and film is because most of the people I know just dump it on the ground. I have a lot of contacts in the industry so if I can help the environment, give the a return, and do something I love then why not. 

I still consider myself a rookie and I know that I haven't scratched the surface of recovery and refining but I have learned a lot and made quite a few mistakes in the process. I am willing to help if anyone needs it and I am also willing to take advice as well. I am on here right now because of some problems I ran into. Right when I think I have one thing down I get thrown a curve. 

I hope everyone has an amazing night and an even better tomorrow. 


Thanks to All

Michael/m6m


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## 4metals (Jul 3, 2014)

I think it is great that you are making a business of this. I notice that you are in the US. have you checked into the EPA requirements to receive waste into your shop? There are exemptions for precious metal reclamation but as silver is a RCRA metal you may need to be licensed to receive this material for processing. The material should be traveling with a waste manifest having you listed as the responsible party for the ultimate waste disposal. 

To prevent issues down the line you should check into the regulations as it pertains to the quantities you will receive for processing.


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## fonnie (Jul 6, 2014)

if the "before" beaker is the industrial fixer, i have a serious doubt.
Industrial fixer tends to be yellowish and becomes more brown the more silver it contains.
I've never seen 20g/liter in industrial fixer, it would be to silver-rich and thus less effective in fixing the industrial film.

Our Xray operators change there developing and fixing solutions when they start loosing there quality.
This results in fixer solution with around 7gr/liter and more dark yellow, brown.

If you state that only 0,37gr of Zinc would be enough, this suggest that your solution was containing almost a third of what you suspected.
So around 6 or 7 gr/liter, which sounds normal for spent fixer.

I suggest you do some more test on the original fixer to determine the silver-contents more accurately

best regards

Fonnie

edit: typo


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## Mmon2616 (Jul 7, 2014)

Yes I have check the with EPA and everything is in line.
I have a license from the environmental quality department. 

As for the before pic it is actually a dilute silver nitrate solution.

I have ran many test and the fixer I get from one technician was completely saturated because he didn't have time to change chemicals so he just used them until they stopped. You can doubt all you want but apparently your getting low silver content. I also clear unexposed film in my fixer until a white cloud (silver chloride) starts to form. I also have a partner that helps and the batch I sent him tested and produced 18.5g/liter. The fixer I receive is from industrial X-ray trucks. I used to so X-ray and we used our fixer until it was almost impossible to clear film. I don't know where you get yours from but it must be from people that keep up their fix. Tomorrow I will put more pics up. The fix I received doesn't have a yellow tint to it. It is almost orange. Even the first rinse has about 10g a liter and it does have a yellow tint. Sorry I didn't post a pic of the fix. There is a guy on this forum that knows That everything I posted is fact. Pm me and I will help you understand what I'm dealing with. I hope you all have a great evening and Monday. Lord knows Mondays are hectic. 
I have what's in the pics but I also have more silver chloride from the batch I am processing later. I totally understand that it's not normal for fixer to have this much but the technicians I know push their chems to the absolute limit. I hope you aren't calling me a liar. Like I said there is a guy on this forum that has taken some and had the same results. 

I appreciate and help and knowledge that is shared with me.

Thanks again to GRF
Michael


Help others so that they don't make the same mistakes you have.


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## Esau Nisalile (Jul 7, 2014)

Hi michael, 
congraturation for the good fixer you are getting. From your picture dont let your silver chloride get dry before conversion to silver metal. Keep it just covered with water so that when doing conversion most of your silver chloride comes into contact with Naoh and the karo syrup, if that is your route. 
Regards,
Esau.


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## Mmon2616 (Jul 7, 2014)

Thanks for you help but that is not silver chloride in the photos. That is dried silver crystals that I cemented out with copper. I appreciate all advice though. As I have learned early on not to let silver chloride dry. I have a big jar that I keep my silver chloride in until it gets full then I rinse. It always has a few inches of water on it so that it does not dry. 

Once again I appreciate the concern and thank you for trying to help.

Hope you have an amazing day
Michael


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## fonnie (Jul 7, 2014)

I'm not calling anybody a liar, there is no reason to.

My experience is that the industrial fixer tends to be lower in silver-contents. Around 7g/liter.

20g/liter, wow I could only hope for that.

The fixer I have seen is also from an NDT company, but maybe they are not pushing there chemicals that far, they're using automatic developing machines but also truck-mounted. (Field Gammaray NDT)

How are you treating the chemicals?

first dropping with zinc? and then dissolving in nitric acid + copper-drop?

best regards

Fonnie


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## Mmon2616 (Jul 7, 2014)

.37g of zinc per gram of silver has nothing to do with my silver return on the 20g liter batch. Sorry if you have never seen fixer with that much silver but I promise my brothers fix has am excess of 20g per liter occasionally. He renders his fix completely useless. It was taking 12 minutes to clear film. Most technicians change theirs mush sooner. I have done many test with zinc and other methods and I found that if you use .37g of zinc you will drop at least a gram of silver. It may actually be less zinc per gram of silver but that's just where I got my best results. 


Do you have any proof or suggestions that state otherwise. I am open and would appreciate any help or knowledge you may be willing to share? I am fairly new at this and am learning as I go. Fortunately I work in the industrial inspection industry and I have many contacts and resources enough to start a business in recovery. Which I have pursued. Any information would be welcome. Thanks for your concern and help. 


Best regards
Michael


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## Mmon2616 (Jul 8, 2014)

I understand that automatic processors fixer are changesd regularly but I am getting manual fix. 

I have been experimenting with several methods of recovery

Method 1 is zinc. I drop the silver with zinc then do a 20% sulphuric bath to remove most left over zinc that did not convert. Then I dissolve in nitric. Then cement out with copper. 

Method 2 is steel shavings. I can't really explain the unit I created but I've made 4 prototypes. I connect them to the tanks I have at my clients place of business and I change them out every 30 days to take contents and melt then dissolve and cement . 


Method 3 I am working on recovering electrically.

I am still learning and trying to experiment with all methods to find the easiest cheapest way to do it with as little time in as possible. The units I have created are just basically plug and sit. It catches %99 of the silver. The fixer never has to leave the job site. But it's still a work in progress. 


If my clients so choose I will also run their cut of the silver through a cell and put it in custom molds for them. There are no recovery or refiners within 90 miles of where I'm at and we have a super high concentration of industrial X-ray companies as I live in a place with at least 20 petroleum refineries among others. 

I may have taken it the wrong way but in this forum I have had many doubters and when you say doubt that generally means "do not believe". I understand not to many people see this type of fixer so I get it. I apologize. I am a honest and fair person and I am always here to help people as well. 

I am also willing to ship you some just so you can experience it for fun. I am generous and want people to have as much fun as I am. May sound strange or ridiculous but I don't care that just the way I am.

Have a great evening and an even better tomorrow
Michael.


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## Mmon2616 (Jul 8, 2014)

By the way. It's not every batch of fixer I get. It's only a few a month that are that saturated. Like I said it gets so saturated that it starts to drop silver chloride. I also have a bunch of unexposed film so I try to push it further when I get it .


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## fonnie (Jul 8, 2014)

I've created something to go the electrolysis way
see my other post.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=20201&p=207654#p207654

quite a simple setup, but it seems to work well.

plastic box, arc-air carbon anode and stainless steel strips for the cathode, DC supply and a pump to keep it moving.

It's ok for smaller quantity, not for huge amounts.

Problem is there is still some silver in the fixer after the process, and maybe the zinc / sulpheric / nitric / copper-drop would be the next experiment, to recover what is still in the fixer.

My doubt was never a disbelief.

You don't need to send me a sample, but I appreciate the offer.

best regards

Fonnie


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## rickbb (Jul 8, 2014)

You don't need to worry about that last bit with an electrolysis unit. Put a steel wool cartridge unit inline with a recirculation pump after you think the electrolysis is done all it can then you will be down to less than 1ppm and below most regulations that I know of for discharge.

This is how I would set this up if I had a continuous supply of fix to process. It would be worth the cost of equipment but would run mostly automated and save a ton of labor. Just change out some electrodes and steel wool cartridges once in a while. Then dry and melt the silver from the electrolysis electrode and process the sludge in the cartridge every 3 to 6 months depending on how often you need.

This is the way hospitals and printing companies did it for decades. The fix went into a electrolysis tank, with the overflow from the tank through a steel wool cartridge. When maintained well there is almost no silver left in what went down the drain and what is recovered is 99%+ pure.


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## Mmon2616 (Jul 9, 2014)

Absolutely. I know electrolysis isn't the way to go for large quantities. Unless I can figure a way to pump the fix through a ss cathode or pay for a very expensive inert cathode. I'm still learning and I know even then with all of the things I've been learning doing it electrically will not get all of the silver out. But I am experimenting and learning and I really appreciate you guys help. I take everything people tell me and try to learn from it.

As far as the cartridge I do have something similar I built. I use gravity to push the fix through at 100ml a minute. I have a few prototypes that have been really good and I can build 4 for 100 bucks. It's just taking time to build and my next issue is security. People could just take them if they really wanted to. One of my client is directly across from the county jail and they have already had problem. I'm pretty sure they wouldn't know what they are looking at and would be hard for one person to pick up and throw over a fence but it could be done. 


Thanks again 
Michael


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## Mmon2616 (Jul 9, 2014)

Fonnie. 

How do you treat your fix? I know you have said a couple ways you do things but is there a way you think is most practical? I am always willing to learn. What all do you recover pms from? Can I pm you? I have many questions just to pick your brain because I want to learn everything I can. 

Best regards!
Michael


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## fonnie (Jul 10, 2014)

for the moment I'm just doing electrolysis on industrial fixer, pumping from a plastic jerrycan to a plastic box, overflow to the jerrycan, and let it run.
It just needs a bit of adjusting amperage as the silvercontents goes down, to avoid black (Sulfide) deposit.

When all (nothing on silverestimation paper) is recovered, I start the next batch.
I now have some jerrycans with 'cleaned' fixer, which I know has still some Ag in it, hence the question of the Zincproces

I've already poured some small bars (around 50gram), but for the moment just collecting for a bigger bar.

In the mean time I'm passing undeveloped film to the 'cleaned' fixer, so I can restart the recovery.

Next plan is to try to recover silver from developed film, going the Fe3Cl way. Problem is finding the chemicals.

You should also note: I'm not doing this as a business, more as an experiment or hobby.

If I would calculate everything (hours, electricity, chemicals, labor, tools) I do not know if it is worth a lot.
I'm not recovering anything other than Ag, and maybe in the future I will start a 'silver cell', to refine the final product. but again: is getting the extra 9 or 2 9's really worth it all? (financially worth for me, as a hobbyist, I mean)

You can PM me, I think

Regards

Fonnie


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## rickbb (Jul 10, 2014)

Actually electrolysis is the way to go for large quantities. 

The economy of scale will pay for a commercial unit from a printing company or such in no time. You can find them used on eBay, Amazon, etc. These units have auto adjusting volts/amperage to compensate for the fluctuation in silver content.

Just setup a recirculating pump to keep the fix flowing from a plastic barrel of fix through the unit until it has recovered all it can. Then put the steel cartridge in place of the electrolysis unit and crank up the recirculation again.

With several sets of barrels you can keep it running while collecting more and just change out the units from barrel to barrel.


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## nickvc (Jul 10, 2014)

I will state an obvious point his forum exists to promote knowledge to all so please don't go to PMs to discuss this keep it on open forum so others may learn :idea:


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## fonnie (Jul 11, 2014)

@nickvc

everybody can PM me, it's a free world after all :lol: 

everything I know, as little as it may be, I will/can share on this fabulous forum . (learned most of it here or on the net)

if you want to know something, just ask. I'm certainly not an expert, just experimenting around, hobby-wise.  

I'll share the little knowledge I have, but I can not answer questions, if they are not asked.

I'm not much of a forum poster, more a reader, so please ask your question, and I will try to give 'my truth' or 'opinion'.

I appreciate the openness of this forum, and the sharing of knowledge, and I do want to share mine.

best regards

Fonnie


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## nickvc (Jul 11, 2014)

Fonnie
My concerns are we don't want any off forum discussions on an already open thread, if anyone has propriety knowledge they are not willing to share don't hint and go quiet, we all need to make a living either through refining or some other profession so im happy if thats the reason members go quiet, I know that maybe some members are scrared to post what they know, we have very many top professional chemists/'refiners who say nothing but happily trawl the forum looking for new methods or confirmation of their ideas, maybe even new thoughts for them to follow.
I remain in the belief of the ideal of the forum as far as I can and help and advise where I can, perhaps I know more than I say but then again perhaps I don't, I'm no chemist and only learnt from experience with all that goes with that but sharing with others has its own benefits that perhaps its why I remain here.


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## Mmon2616 (Jul 11, 2014)

See as I have been researching and gathering most information I've learned and been told by people that I think are pretty reputable that electrolysis was not the way to go. I am glad to hear from someone that uses it

In the beginning I was considering going with it but everyone I was hearing from said just use steel wool cartridges. I can get steel shavings for about 8cents a lb at a local junk yard. It's mush cheaper than the steel wool and a lot better for the type of cartridges I am designing. It has filtration and a few other little gadgets that ensure that 99% of the silver is recovered from the fix. It cost me about 100 bucks and about 3 hours to build 4. I'm running into some minor issues but it's been pretty affective. 


I have (3) 275 gallon tanks at my clients shops. One is strictly for fix and one for desilvered fix. The other is for rinse waters. Right now I am learning and my clients know that. 

I really appreciate all the information you are presenting. This is helping me tremendously. I want to learn the most cost effective way to process this fix. I absolutely love recovery and refining and hope to learn as much as possible.

If you need some ferric chloride I can send you the info via pm. I have a supplier that can ship anything you need at a fair price or I can get it for you and ship. It is 98%. It costs about 20 bucks for 500g. The larger the quantity the better the price. 

The reason I asked for you to pm me is because I would like to discuss some issues that I don't think should be discussed in a public setting. It's not that I am trying to keep anything from the forum it's just for professional reasons. It seems this forum is micromanaged at times and I have asked certain questions and got replies that weren't beneficial to what I was doing. I am very hesitant about posting questions because of this. It seems as though some people have to much time on their hands. I know I know very little about recovery and refining and have a lot to learn so some of my questions may seem ridiculous to some. I don't have a degree in chemistry and haven't dealt with this in any form until I started about 9 months ago. I hope we can continue this discussion without further problems. 

I am on my phone so I have to go back and read your post.


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## Mmon2616 (Jul 11, 2014)

Sometimes I would rather talk directly to someone without input from others when I believe I will get discouraging replies. It's not you. It's me.


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## Mmon2616 (Jul 12, 2014)

Fonnie, I just read your post about the electrolysis units from printing companies. Do you happen to have the name or brand of the one you would recommend? I will do some research in the meantime to learn more about them. Right now I just use Inc and steel shavings. I like zinc but it cost about 19 cents a gram. I buy it in 2.5k jars and it is trace metal but it still contaminates no matter how carful I can be. 

I have just set up a laboratory and am trying to learn how to run a silver cell to get .999 silver. Is there a way to purify silver without having to use copper? I try searching here and other places but I run into information that is hard to translate to my situation. If you have any experience with this I greatly appreciate your input. Like I've said a dozen times I am not asking you to do the work for me just lead me in the right direction if you so choose. If not I will do the research and hands on to learn what I need to know. 

Thanks again
Michael

Ps. I have a supplier that is 5 mins from my home that can get any and all chemicals you will need. If you want the info let me know. They ship directly to you. I can also ship you a catalog from them. They sale a ton of things from beakers to photometers.


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## Palladium (Jul 12, 2014)

https://www.youtube.com/watch?v=qSzjH9cSDpw


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## fonnie (Jul 12, 2014)

Mmon2616 said:


> Fonnie, I just read your post about the electrolysis units from printing companies. Do you happen to have the name or brand of the one you would recommend?



Michael,

I don't have an electrolysis unit from printing companies.
I've build one myself.

I've salvaged a fixerpump from an industrial x-ray automatic developer-machine.
With some (gardenhose) tubing and an anti-reflowvalve. I've made it possible to suck up the fixer from the jerrycan, and getting it to the plastic box.
Via an overflow the fixer runs back to the jerrycan.

on top of the unit, i've placed some plastic insulation strip/plate (2 plastic sheets with foam in between). in this strip i've drilled some holes the size of the arc-air carbon electrodes (the ones they use in welding, to remove groundlayers or weldingdefects)
In my setup I use 2 of them (those are the anodes), you just have to strip the very fine layer of copper of the electrodes.

I've taken 2 stainless steel strip (5cm wide, 35cmlong, thickness about 1mm). those strips are attached with a stainless screw on the side of the plastic strip, since it is a hard foam, i works well, and I can reposition them like I want. (those are my cathodes)

For a power supply I have a 15 volt 3A DC powersupply (Volt and Amps are regulated)
Connection to the anodes and cathodes is made with simple cables with bananaconnection and crocodileclips (don't know if the are called like that, but you get the drift.

Now for the electrolysis.
step 1 is to get the fix flowing
step 2 is to regulate the amps (supply in Ampregulationmode) according to the size of the cathodes, for me about 1.3 amps
the voltage will adapt itself to about 1.5V, but this depends a lot on the distance between the anodes and cathodes.

Let it run, and you will notice a light gray deposit on the surface of the cathodes, the recovery has started  
Now you need to regulate the powersupply, as the fixer get depleted, you will have to regulate the amps, because you will have to keep the voltage from rising.

Don't push it, let it go, because to much amp and voltage will get you deposit of sulphides, and this means your deposit is less pure. 
AgS will need to be stirred with an Iron rod, during melting to get rid of the S.
If you can avoid the AgS deposit, you don't get to treat it afterwards.

If allmost all the silver is recovered, you can unscrew the plate from the setup, and scrape off the silver. I use a Stanleyknive or a cookingplatescraper (has a sort of a razorblade in them

Next time I run a batch, I'll correct the values, because this is all from memory.
I'll take more pictures
And I found somewhere the correct (?) powersetting to surfacecalculation, but that to I will have to look up

I've posted somewhere in this forum a very helpfull publication from Kodak, it's called J10 and discusses the different systems of recovery.

For the moment I'm still pushing unused film trough the fixer (if time allows) so I can start the next batch.
Been busy with another project (non PreciousMetal related, building my own windmill)

about sending chemicals, please don't, Belgian customs-service will not be very happy, I think

@nickvc
I don't have special knowledge, and I'm not even doing the recovery as a business.
I really love/support the idea of Open Source, sharing everything to anybody, making a better world of knowledge, helping others, growing ideas,...

About the fact whether or not electrolysis is the way to go or not, like stated before, I did not calculate cost of equipment, nor cost of running the thing. Electrolysis is a way to recover silver from fixer, problem is it will not recover everything, so you will need another afterprocess. Hence my question about the zincproces

questions or comments
Let me know

best regards

Fonnie


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## Mmon2616 (Jul 14, 2014)

That's great Fonnie. I appreciate the help

Sorry didn't know you were in Belgium. Congrats in the World Cup. You guys did better than us. Lol

I knew that it did electrolysis did not recover all of the silver and a secondary cartridge was necessary to get silver content to the right ppm. 

I talked to a very smart man that has been recovering and refining for 30 years and everything he tried explaining sounded like gibberish. He was telling me about inert cathodes, platinum cathodes, and other types of cathodes for recovering silver from fix. The problem it wasn't cost effective. There is so much to learn. I am just trying to create the best way for me and the knowledge I have right now. As I learn more I will try more. I am so glad you are sharing your knowledge for it is appreciated. 

Obviously you know a great deal more than I. I appreciate your insight into electrolysis for fixer. I will consider everything you have explAined. I have yet to gain enough knowledge to try it but with your help I have a better idea of what to do. The great thing about this forum is that there is endless amounts of information to learn from. That is also the toughest part of this forum. Grant it if your going to be successful in the recovery and refining business you will have to do a ton of research. I think the reasons for most forums is to be able to ask a question and have it answered by someone that has the experience and has made the mistakes. If I had more knowledge about this industry I would share with anyone as you have. Thanks again. 

I am going to set up a small scale electrolysis unit within the month and I will have pictures to share. As I go back and read your post I may have I few questions. I hope you don't mind me asking. I am stuck using my phone right now because a bolt of lightning stuck a tree right outside my house which arced and hit my wifi dish. I am posting pics of the tree about 10 feet from my house just to share. Thanks again.

Best regards
Michael


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## Mmon2616 (Jul 14, 2014)

Palladium, thanks for the video! Very helpful!


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## fonnie (Jul 14, 2014)

I think setting up a small scale electrolsysis-unit is 'easy'.
No need for platinum cathodes , just Stainless steel strips will work fine, arc-air carbon electrodes for anode.


Upscalling it would be more difficult, especially when you want the unit to be selfregulating. You would need some aggitation, and adaptive powersupply.
Maybe this would also mean the electrodes need to be upscaled, and maybe some other materials.

My setup requires regular followup, and adjusting setting, no problem, just a few minutes attention every some hours.
Since I keep my amperage low, I can leave the setup alone for longer hours (even overnight). But this is not very time-efficient.

If you are in the bussines over recovering, you would want to go as quickly as possible, pushing the unit, and finding the balance between depositrate and silverquality.

I'm sorry to hear about the tree, and the damage, I hope you are well.

best regards

Fonnie


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## Mmon2616 (Jul 14, 2014)

Thanks for your concern. Everyone is okay. The tree is a little bruised. Lol. 

As for the platinum/titanium cathodes that was just discussing a few ways to remove 99.9 of silver from fix using electrolysis. I'm not sure how or if it really can be done.

What size arc air electrode is pictured? What size are your Jerrycans? I'm just curious. I have some 55gal plastic drums and quite a few polypropylene totes that are 275gal and a few 375 gal totes. 

How long have you wen recovering silver? Do you do any other pm's ? I recover and refine gold from electronics and jewelry as well. 


I recalculated the completely saturated batch of fixer. I told you it was about 20g a liter. I for some reason screwed up the liter calculation. It turned out to be 17.75g a liter. Each batch I was getting to experiment with is 12 gallons.(47.76L) now that I have the 275 gal totes I am putting my cartridge so I don't have to worry about it except for once a month. I really want to do this with electrolysis though. The reason being is because when you add a metal to the recovery process you contaminate the final product. I also enjoy watching silver crystals grow. 

Do you have a background in chemistry? You have a lot of knowledge to share. By no means are you a newbie but as i stated in another post I know even if I study for 10 years no me stop I would still only know a small fraction about refining. There is a lot of math involved. There is never just one way to do something. There is always several different ways to get the same final results with each method having different pros and cons. 

Thanks again as always. I appreciate your help. I apologize that I haven't given you much help. I know a little about the zinc process but not enough to actual break down the method. I am still learning and researching that why I'm here everyday.

Have a great day and I hope all is well.
Michael


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## fonnie (Jul 15, 2014)

Not being home for the moment, from memory:

carbon electrode: diam 10mm (2 of them in the tank)
jerrycans are 25liter
electrodesize stainless : width 5 à 6cm, submersed part 20cm (also 2 in the tank)

distance between electrodes: cathode to anode about ( 5 cm)

amperage is not to exceed 1Amp/dm², to avoid black deposit
Since I have a total of about 4dm² (2sides / 2 electrodes) I'm working on about a quarter of the max current density. and that's why it is slow, but also why I have no black deposit

Don't expect seeing cristals grow in the electrolysis, it's not like the silvercell.
The deposit is a fine, greyish powder, sometimes the first layer is even solid silver flake, it peels off when scraped
The flake is a bit harder to get off the electrodes, but with a kitchenscraper, it goes rather well, with a bit of practice.
After cleaning the cathodes, I do a hot water wash and dry the silver in a coffeefilter in a pan, slowly, till dry.

Since this is all from memory, it's not that accurate.
Next time I go down to my lab, I'll take some exact measurements and photo's.

I've started the recovery 2 years ago, but on and off, depending on the amount of fixer I've collected.
Not doing any other PM, just silver.

Collecting the silver is the easy part, getting a nice silverbar at the end is something else. :lol: 

It seems you have alot more Fixer to treat, you're talking 55Gall, 275Gal and 375Gall, wow, that's alot.

I think the setup I have, could scale up to a certain extent, adding extra carbon rods and stainless sheet, will increase surfacearea and you could increase amps.
But you need a good agitation, or flow around the electrodes.
I vagely remember that the depositrate is somewhere around 8gr per hour per amp, max. 
In order to deposit big quantity, you need big amp, and thus alot of cathode surface.

How do you measure the silver contents of the fixer?

best regards

Fonnie


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## fonnie (Jul 15, 2014)

@moderators: if you think this should be posted as a separate thread, feel free to move it.

Ok, went down to my shop, and took some measurements and photo's. This is going to be a lengthy post. I might need several posts.
I'm from Belgium, so everything is metric.

My complete setup consist of a plastic box, plumbing, electrode-support, electrodes, storage tank, and power-supply and cables




The cathodes are 2 strips of stainless steel (6,5cm x almost 30cm) the submerged part where the action happens is 18,5cm, the strips do not touch the bottom of the grey container.
The anodes are 2 arc air carbon electrodes, stripped from there copper layer, diameter 10mm. They are passed through holes in the supportplate, and they touch the bottom, because nothing is holding them back.

You will notice several holes in the support-plate, leftover from some setup-testing, but also handy to reposition the electrode or place some extra electrodes.

From the top view you can see that the position of the anodes versus cathodes is slightly of center, allowing for and electrode-spacing of 5cm.

on the left of the grey container is the inlet, halfway height, allowing for a constant stream of fixer passed the cathodes. this avoid the need of agitation or a rotating cathode. This setup is okay for a small setup at low current.







on the right side, there are 2 overflows, connected by gardenhosetubes back to the storage tank.




This is something I need to redesign, because it creates a slurping sound, which is quite annoying.




The fixer is pumped around by the fixerpump (salvaged from an automatic processor), not visible on the photo's is the anti-reflowvalve on the end of the tube inside the tank. It keeps the pump from cavitating.

As a powersupply, it's a standard 15V 3A DC regulated powersupply, set at Ampregulation.

During the recovery I start with about 1A, the voltage changes to about 1,6V.

When the fixer gets depleted from the silver, the setting have to be adjusted, normally I lower the amps to avoid overvoltage.
This will prevent the formation of AgS (black and muddy) and keeps the deposit clean and pure.

The harvestphoto's are from a previous 'run'. you can see that it's a grainy structure, not real powder (like you will have when cementing) 
The flakes you see, are scraped of the cathode. Notice the bright shine and real metalfinishlook.

In the past I've poured some bars, after a good rinse and drying of the harvested flakes.
They look rather nice, I think.
I've just used some Borax during the melt. 
There weight is about 35gr, or about 1tr Oz


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## fonnie (Jul 15, 2014)

not enough room for the pictures, so part 2


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## fonnie (Jul 15, 2014)

and post 3 about the harvesting










I hope this post was not too long.

I've posted this to show that an electrolysis setup does not need to be complicated, when used for small batch recovery.
I don't know if up-scaling this to something that is capable of treating larger quantities of spent fixer is possible.

best regards

Fonnie


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## rickbb (Jul 16, 2014)

You can use a small tank recovery unit for large volume fixer by placing them in-line with a recirculation pump connected to larger tanks of fix.

When I was in the printing business I had a 4 gallon recovery unit processing fix from 4 different automated film processors going through about 30 to 40 gallons of fix per week. The processers were plumbed to a 30 gallon holding tank that the recovery unit was in-line with the recirculation pump. The over flow from the holding tank went to a steel wool cartridge before the sewer drain.

It worked quite well, recovered many pounds worth of flake every 3 months. This was in the 80's when silver went up as high as $3.50 an oz. :lol:


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## Lou (Jul 16, 2014)

Bear in mind that you should talk to your local city/municipal waste water treatment folks about your silver recovery system, as it may still need to be permitted! Routine maintenance and exchange of the steel wool canisters for final effluent polishing is a good thing to have on a written schedule.

I think everyone knows that silver ion is bad, bad news if it makes it down to the publicly owned treatment works and does a number on the good bacteria digesting sludge.


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## Mmon2616 (Jul 20, 2014)

That's really nice Fonnie. I am going to use the information you have shared to build a small scale experimental setup. Pictures really help. I will post pictures of mine an the building process. 

Lou, I have contact local authorities on waste disposal and everything in need is completely understood. Safety and the environment were the reason I decided to recover from fix. A lot of local nDE companies have people that just dump on the ground. I love recovering and refining and it help the environment. There are regulations that are here to protect our local environment and I believe that anyone from your large corporations to your garage refiner should follow these regs. I am trying to build a company so I know following the rules is a must. If I was to do something illegal it would put me out of business before I really start. I appreciate the concern and look forward to learning from you as well as possibly doing business with you. 


Hope all have a great day!
Michael


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## Erceg (Sep 13, 2014)

Wow, this was very informative topic and i learned much from it but more I learn more questions I have, especially with electricity which is not my strong side  
I hope you will be able and willing to help me out and share some advice with a newbie.
First about cathode: stainless steel or inox, do you use magnetic on non magnetic one?
Second, is there any anode to cathode surface ratio which must be meet? I'm asking this because I have some simple design for big surface cathode (~17 dm2) so to know how many C anodes i need in order shorten the time for 1g of Ag to be reduced (g/A/h).
About that last, just to make myself clear, 1A/dm2 of cathode surface is max current but in order not to get sulphides i must use only 1/4 of max. current? Or is there some absolute A and V value that must not to be crossed?
That leads me to next question about power supply. Fonnie, your power supply regulates only A? would it be possible to instal voltage regulator (similar to one found in light bulb light intensity regulators) between power supply and anode to regulate V so A regulation would not be necessary?
Someone here was talking about inert platinum electrode and that is expensive. It is if it is pure platinum, if it's Pt plated that is different story and it should work as well as one from solid Pt. Just an idea 
I have more question but i forgot them...maybe it is better that way, I don't want to be banned after my firs post 
I'll post cathode sketch later to hear your opinion on design. 
If answer on any of my questions lies in some other topic on this forum that i have missed i would appreciate just a link, no need to answer question directly 

Edit: found answer to inox question


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## Erceg (Sep 15, 2014)

There is only cathode on picture. There supposed to be 1 anode per vertical cathode spacing. So in this instance three. Idea is to be able to put as many vertical plates but that all have adequate electrolyte flow by using only one source of electrolyte current. Because of that the plates are curved in direction of the current but at some angel to it so that they could "chip away" parts of the current as it passes by...like cheese on the grater. Horizontal fins are also at the angle to direct stream of poor solution upwards to overflow. If they would be parallel to left and right side of container and flow input in the middle, the most left and most right plate would not get enough flow and make sulfides.
One other condition of this setup is that depth of plates (shorter dimension) should be bigger than distance between them, otherwise it would be same as using one big cathode sheet.
Looking at this after few days i think it would be better to loose one horizontal plate.

Any input would be extremely useful as i am only a beginner and just in phase of learning to see if I can even "walk the walk".


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## fonnie (Sep 16, 2014)

I think the surface is the governing parameter, so more surface, more amperage possibel, higher deposit.

But: your setup seems to use horizontal and vertical plates, which should be ok, except for the electrical connections, since fixer is corrosive, your contactpoints will corrode if not protected.

Mind you, even the vapour from the fixer will cause corrosion.

Corrosion could be a source for contamination, so try to avoid that, the silver in fixer is pure, so try to keep it that way.

you could use parallel vertical plates, alternating cathodes and anodes, leaving the current bearing contactpoints out of the fixer.

But as I stated before, upscaling would require current and voltage regulation and enough agitation (bigger pump)
I think the concept of rotating drums is basically the next step, the rotation of the drum, is the source of agitation, the surface is relatively big, and thus higher deposit is possible.
Mechanically a bit more challenging, slipcontacts and motor (gearbox) would be needed.

best of luck with your project
Fonnie


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## Erceg (Sep 17, 2014)

Thank you fonnie for your reply.
For corrosion thing, thanks for warning me about that. The idea was to put another horizontal plate at the top of the cell that will hold cathode ad parts of it would be on the outer side of cell, so not submerge in electrolyte. But i didn't know about vapors, I'll be taking that in account.
I taught that silver is not pure, even in rotating drum setup. I taught that is about 96-98% pure because there are always some sulfides that sneaks by ?

"you could use parallel vertical plates, alternating cathodes and anodes, leaving the current bearing contactpoints out of the fixer."

I taught about that but as i said electricity is not my strong side and i didn't know how would el. current behave. For example: we have one set of cathodes, behind set of anodes and then another set of cathodes. Electrolytic flow is K->A->K. I don't know how will electricity be split between to sets of cathodes taking in consideration that electrolyte with more Ag is coming on first set of electrodes than on the second one. I think it would be a nightmare to regulate current in that setup not to get sulphides. 
If you meant setup like k, a, k, a and the flow of electrolyte is coming at the same time to all of them, that is basically the same thing as my setup without horizontal cathode. Do you think it interferes with or inhibits flow of electrolyte too much?

Yes, rotating drum would be ideal, and I would build one but that slip contacts are giving me a problem. 

Do you have an opinion about that idea of putting volt regulator between ampere regulating power supply and anode? If my el. input has fixed A and V does that negate need for regulation ? There can not be more A or V in cell than what i put in ?
Other idea was just not to make recirculating cell but one time flow cell. The regulation would be needed in the beginning until concentration of Ag in cell reaches equilibrium between input and output of Ag. Only problem then would be a big thank from which electrolyte would be fed to cell (at least big enough to fill the cell for couple of hours...small input pipe maybe?) 

I'm just tossing ideas here. You are free to say that i should stop re-inventing the wheel


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## fonnie (Sep 17, 2014)

the silver in fixer is pure. getting it out in that form is the tricky part.

I mean, there is only Ag in the solution, no other metals, so avoid introducing elements like Fe, Cu, ...
AgS starts forming only when there is too much current and not enough silver left. So don't put too much current, and keep the Ag level high enough, meaning you do not want to try to get the last bit of silver out of the solution. I will only give you the risk of forming AgS

The parallel setup: anode/cathode/anode/.... increases the surface of the cathode, which allows for more current.
Current only flows from anode to cathode, and not the other way around, your scheme would be A >> K << A, (in reality the electrons are flowing the other way around, depending on convention really) 

The carbon anode is serving both the cathodes in the same time.

Voltage is determined by the distance between the electrodes (and the concentration of the silver in the fixer), current is what should be monitored. 
I'm adjusting my current to keep my voltage down, meaning: since the silver is deposited, there is less in the solution, and the voltage would rise, for the same amount of current. But this means there is actually too much current for the amount of silver present, and sulfides start forming.

Main thing is to keep a constant flow on the surface of the cathodes, to avoid local spot of silverpour solution (again sulfide forming)

I would set up the electrode so that the flow would not first hit one cathode, but all at the same time. (crossflow).
Don't aim the flow on the flat surface of the cathode, but more passing by, on the edge.

I think it is very difficult to deposit all the silver is one flow, and personally have not tested that, recirculation seems easier to monitor, to me at least.

i would start small, like my setup, and try to learn how it behaves, fiddle around with voltage (electrode spacing) and current (stay below the max per Sq dm). Get some silverestimatepaper or use the copperwiretest (search on the forum) and try to get some data of your experiment.

good luck and stay safe

Fonnie


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## butcher (Sep 17, 2014)

fonnie, 
You have included lots of tidbits of good information in that post.
Good post.


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## Erceg (Sep 18, 2014)

Fonnie thank you for your quick reply.
It seams that you missed point of that scheme. It was shoving flow of liquid, not flow of electrons in order to show that liquid on first cathode is not same as one at second cathode. So the electricity distribution would not be the same on those two cathodes and I don't know would that make regulating A with only one power supply impossible? 
About your scheme, is there any reason to be two anodes per one cathode? Does that have anything to do with anode to cathode surface ratio I asked about? 
The fresh flow is actually hitting all the cathodes. Remember that grater and cheese comparison...
I was wondering even if i get sulfides, can I process them with product of sodium sulfide method... as far as i know product is the same thing? So after running cell "by the book" and recover pure silver, I remove it from cell and then "burn" the rest of the silver from solution into sulfides.

I think I will do couple more runs with sodium sulphide method which works with no problem. I was considering electrolysis just because it gives back fixer more viable for re-use later on. Some people offered to buy it back at reduced price if I can make it strip silver again.
Than you for your information and advice. It helped me a lot


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## fonnie (Sep 18, 2014)

there is no reason for the 2 anode, 1cathode. You could add as many as you want, the cathodesurface is the most important. 
Like said in my previous posts, I use Arc-Air carbon rods, their surface is certainly much smaller than my cathodesurface, I doesn't matter.

they seem to have enough surface to carry the current (I'm only putting 1 amp through them, so they are ok)
Search for a rotating drum recovery unit patent online, the cathode surface is always much bigger than the anodes they use.

if your flow is straight on the sharp edge of all cathodes, i don't think there would be any current-difference issue. If there is enough flow, the difference in concentration of silver would only be marginal.

If you are trying to re-use the fixer, there are some issues to consider.
Don't go too low on silvercontent, because depositing sulfide is altering the chemical composition of the fixer, making it useless for re-use.
watch for changes in pH, watch temperature...

I think in one of the Kodak publications there is some mentioning of reusing fixer, you would certainly have to add something, or replenishing with fresh fixer.

I have reused some of the depleted fixer, to get the silver of undeveloped (expired) film, so it would be re-usable. have not tested this with real x-ray for commercial NDT work, I think there might be quality issues with re-used fixer. Be careful selling the fixer back, they might claim you when their client are not accepting the radiographs.

regards

Fonnie


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## Erceg (Sep 19, 2014)

I was planing to strip about 80% (or experimentally determent % after which sulfides start to form) and then give 1 to photo studio for testing on some unimportant pictures or whatever they do. If they are satisfied then we would do business. I would not even try to resell to hospital or some other "important" user because that quality drop. I'm just at J11 with Kodak so i must first finish that of. 
But that is just a plan. I must learn much more in order to do that. As you said, i must learn reactions beside reduction of silver that are happening in cell, then I need to see how much anode is eroding under different values of current, I didn't even started learning about pH influence....there is still much work ahead of me.


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