Industrial Fixer
- Thread starter Mmon2616
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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.
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.
Mmon2616 said:
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
Attachments
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
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
Attachments
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
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
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
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
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
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
@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
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
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
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
rickbb
Well-known member
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:
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:
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.
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.
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
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
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
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
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".
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".
Attachments
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
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
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
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
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
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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