fonnie,
You have included lots of tidbits of good information in that post.
Good post.
You have included lots of tidbits of good information in that post.
Good post.
Industrial Fixer
- Thread starter Mmon2616
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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
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
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
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
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.
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.
