Non-Chemical Silver

[Mr T]

I'm sorry for my slang

 

[Golddigger76]

Cracking here is grinding corn or other grain to a smaller size, or what your car windshield does after a rock hits it to hard.
I'm not complaining, only confused a little.

Edit: corrected spelling

 

[Yggdrasil]

I'm sorry for my slang

No need to be sorry, but in interest if understanding each other, it is wise to avoid it in the future or at least explain it directly

 

[kurtak]

What ph am I looking my rank to be set to?

It's not so much a question of Ph - it's more a question of ORP (Oxidation Reduction Potential) you need a ORP meter not a Ph meter if you are going to use "free nitric' to balance you electrolyte

For what it is worth - though adding free nitric to the electrolyte is "one way" of balancing your electrolyte it's not the only way & IMO there are better ways - if you are going to do it with free nitric you really need a ORP meter - other methods don't need an ORP meter

Do you actually understand how a silver cell works ?

Please post your understanding so we can see where you may (or not) have a mis-understanding of how a cell works --- then we can move forward with options of running your cell using 80% silver anodes

Kurt

 

[Mr T]

It's not so much a question of Ph - it's more a question of ORP (Oxidation Reduction Potential) you need a ORP meter not a Ph meter if you are going to use "free nitric' to balance you electrolyte

For what it is worth - though adding free nitric to the electrolyte is "one way" of balancing your electrolyte it's not the only way & IMO there are better ways - if you are going to do it with free nitric you really need a ORP meter - other methods don't need an ORP meter

Do you actually understand how a silver cell works ?

Please post your understanding so we can see where you may (or not) have a mis-understanding of how a cell works --- then we can move forward with options of running your cell using 80% silver anodes

Kurt

Hi yes I use an orp meter for my gold refining, what figure am I looking for to have a balanced tank ?

 

[Mr T]

It's not so much a question of Ph - it's more a question of ORP (Oxidation Reduction Potential) you need a ORP meter not a Ph meter if you are going to use "free nitric' to balance you electrolyte

For what it is worth - though adding free nitric to the electrolyte is "one way" of balancing your electrolyte it's not the only way & IMO there are better ways - if you are going to do it with free nitric you really need a ORP meter - other methods don't need an ORP meter

Do you actually understand how a silver cell works ?

Please post your understanding so we can see where you may (or not) have a mis-understanding of how a cell works --- then we can move forward with options of running your cell using 80% silver anodes

Kurt

Hi Kurt, no I don't have much understanding of how a silver cell works, me and my friend are trying to start a small refining company, we have mastered the gold side, just struggling with the silver now.
Any help or advise would be much appreciated.

 

[kurtak]

Hi yes I use an orp meter for my gold refining, what figure am I looking for to have a balanced tank ?

I am sorry but I actually can't answer that as anytime I have run my cell with anodes that are less then 97 - 98 % silver I have used two other methods instead of trying to balance electrolyte with free nitric

I just know that when using free nitric to balance the electrolyte - without an ORP meter you are risking adding to much free nitric which results in the nitric dissolving silver - as well as base metals - at the anode - faster then the cell is able to displace silver from the electrolyte to cathode --- because the nitric (to much) is dissolving silver & base metal faster then the displacement operation of the cell the base metals that are dissolving along with the silver are cementing the silver as it dissolves thereby causing the problem you are seeing

In other words - you have a chemical reaction taking place at the same time as an electrolytic reaction - because of (to much) free nitric

I avoid this problem by using one of the two following methods - which IMO is better then using free nitric to balance electrolyte (as you don't risk over adding nitric)

First you need to understand how the cell works - it works by displacing silver from the electrolyte to the cathode - as the silver is displaced from the electrolyte to the cathode - it "frees up" a very small amount of nitric which goes to work at dissolving the metals at the anode thereby putting metal ions back into the electrolyte at the same rate as metal ions being displaced from the electrolyte --- because the anode is impure (silver + base metals) the base metals dissolving at the anode starts corrupting the electrolyte with base metals

In other words - silver ions in the electrolyte are being "depleted" & replaced with base metal ions & when you get to a point of less silver ions & more base metal ions you start have co-depositing of base metal with the silver at the cathode due to an "upset" of the ratio of silver to base metal in the electrolyte

You can overcome this electrolyte upset (at least somewhat) & get longer run time before concern with co-depositing by ------------

1) starting with a HIGH silver concentration of silver in the electrolyte in the first place (like 2 - 3 times normal) because it takes longer to upset the "ratio" of silver to base metals in the electrolyte --- or -------------

2) if you start with a lower (normal) concentration of silver electrolyte - once the electrolyte is corrupted (but before co-depositing) remove some of the electrolyte & replace it with some more fresh silver electrolyte in order to increase the silver to base metal ratio in the electrolyte

There is a third method but that for another post which I don/t have time for today

Hope that all makes sense - if not - ask

Kurt

 

[Mr T]

I am sorry but I actually can't answer that as anytime I have run my cell with anodes that are less then 97 - 98 % silver I have used two other methods instead of trying to balance electrolyte with free nitric

I just know that when using free nitric to balance the electrolyte - without an ORP meter you are risking adding to much free nitric which results in the nitric dissolving silver - as well as base metals - at the anode - faster then the cell is able to displace silver from the electrolyte to cathode --- because the nitric (to much) is dissolving silver & base metal faster then the displacement operation of the cell the base metals that are dissolving along with the silver are cementing the silver as it dissolves thereby causing the problem you are seeing

In other words - you have a chemical reaction taking place at the same time as an electrolytic reaction - because of (to much) free nitric

I avoid this problem by using one of the two following methods - which IMO is better then using free nitric to balance electrolyte (as you don't risk over adding nitric)

First you need to understand how the cell works - it works by displacing silver from the electrolyte to the cathode - as the silver is displaced from the electrolyte to the cathode - it "frees up" a very small amount of nitric which goes to work at dissolving the metals at the anode thereby putting metal ions back into the electrolyte at the same rate as metal ions being displaced from the electrolyte --- because the anode is impure (silver + base metals) the base metals dissolving at the anode starts corrupting the electrolyte with base metals

In other words - silver ions in the electrolyte are being "depleted" & replaced with base metal ions & when you get to a point of less silver ions & more base metal ions you start have co-depositing of base metal with the silver at the cathode due to an "upset" of the ratio of silver to base metal in the electrolyte

You can overcome this electrolyte upset (at least somewhat) & get longer run time before concern with co-depositing by ------------

1) starting with a HIGH silver concentration of silver in the electrolyte in the first place (like 2 - 3 times normal) because it takes longer to upset the "ratio" of silver to base metals in the electrolyte --- or -------------

2) if you start with a lower (normal) concentration of silver electrolyte - once the electrolyte is corrupted (but before co-depositing) remove some of the electrolyte & replace it with some more fresh silver electrolyte in order to increase the silver to base metal ratio in the electrolyte

There is a third method but that for another post which I don/t have time for today

Hope that all makes sense - if not - ask

Kurt

Thank you Kurt for taking time to explain the process to me, it is much appreciated, and yes it does make sense, I've seen it happen in front of my eyes.

 

[Mr T]

I'm really struggling go obtain Crystal's from my silver refining bath, I seem to be making silver powder, you seem really experienced in the process, I have an orp meter, I e added more silver nitrate and demin water, I've made sure that the free nitric is lower by leaving some silver crystals in the electrolyte mix when weve added to the bath, any advise would be greatly appreciated.
Regards Tye.

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[Yggdrasil]

I'm really struggling go obtain Crystal's from my silver refining bath, I seem to be making silver powder, you seem really experienced in the process, I have an orp meter, I e added more silver nitrate and demin water, I've made sure that the free nitric is lower by leaving some silver crystals in the electrolyte mix when weve added to the bath, any advise would be greatly appreciated.
Regards Tye.

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I have moved the post her, it belongs with the your other posts.

 

[Yggdrasil]

I'm really struggling go obtain Crystal's from my silver refining bath, I seem to be making silver powder, you seem really experienced in the process, I have an orp meter, I e added more silver nitrate and demin water, I've made sure that the free nitric is lower by leaving some silver crystals in the electrolyte mix when weve added to the bath, any advise would be greatly appreciated.
Regards Tye.

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What Voltage and Amperage are you running and what is your distance between the Anode and the Cathode?

 

[Mr T]

We are using 160 constant amps he volts fluctuate, its 3 volts at the moment, the distance between anode and cathode is 50mm

 

[Yggdrasil]

We are using 160 constant amps he volts fluctuate, its 3 volts at the moment, the distance between anode and cathode is 50mm

I think that to get bigger crystals, the voltage need to be as low as practical, preferably under 2 V.
The big guns might chime in.

 

[kurtak]

Hmmm - not exactly sure - but my first suspect is that your electrolyte is to dilute

Please tell us exactly how you are making your electrolyte - starting with the silver you are using to make the electrolyte with (in other words are you making the electrolyte with the same 80% silver as the 80% silver you are trying to refine - or other silver)

So (just for starters) please tell us step by step how you are making your electrolyte

Also - is this a moebius cell (anodes & cathodes hanging vertical) or a Thum cell (anode & cathode horizontal to each other)

Kurt

 

[sar]

Normally when you start the electrolysis with fresh water and acid some sponge shaped mass of silver reduced on the cathode and goes up to the surface of electrolyte.
Some advices:
First of all remove silver sponge floated on the surface of electrolyte because of short circuit between anode and cathode.
Don't start the electrolysis with fresh water and acid. Add silver nitrate solution at the beginning or keep some electrolyte from previous batch.
Your anode is very impure ( 20% impurity, and it is visible on the video you sent because of the colorful turquoise of electrolyte), if you want to have a pure silver in cathode replace half of the electrolyte each batch with fresh DI water and nitric acid (for each 10 litter of water add 0.8 kg concentrated acid) .
Hope these help you.

 

[sar]

We are using 160 constant amps he volts fluctuate, its 3 volts at the moment, the distance between anode and cathode is 50mm

By the way set the voltage at a constant figure for instance 2.5 V, not amps.

 

[4metals]

what figure am I looking for to have a balanced tank ?

Are you using a packaged silver cell by Italimpianti or Oro studio? What concentration of Silver do you run the bath at? Do you titrate the solution to determine the silver content and then add nitric to maintain it in a range? These are the things to control a production Silver cell. Starting with an alloy with 20% Copper puts you on a path to changing your electrolyte often as the Copper builds up too high and begins to deposit with the Silver, lowering your purity.

Titrating the Silver is relatively easy using a Volhard titration and I can give you specifics for the titration, which, combined with nitric additions allows you to control the cell. You should also consider routine copper analysis to keep the Copper in check. Is all of your feedstock 20% copper?

 

[snoman701]

Does the copper actually deposit at low voltages, or just get entrapped into the tiny crystals?

 

[4metals]

Does the copper actually deposit at low voltages, or just get entrapped into the tiny crystals?

Both actually. A lot of copper contamination comes from incomplete rinsing. A good rinse followed by a spin drier to get the last of the rinse water (still slightly contaminated with Copper) off the crystals. But when the Copper content of a cell gets as high as the Silver content it will plate out at the lower current densities along with Silver. One refining technique to clean up silver is using a cell with high Copper content. The resultant Silver deposits will be mostly Silver (depending on how low the Silver content of the feedstock was) but copper will plate out as well. Just not as fast or efficiently.

 

[BGDOCK]

Why not use paper ph testing strips
Was the pier to the cell on?