# First attempt at silver refining



## Gsracer

After reading for the past few months and watching numerous videos i gave it a shot today. Id say overall it was a success. I do have a few questions though.


Here was my process.


As a trial run I tried a 90 % silver coin weighing in at 12.33 grams and a demitasse sterling spoon weighing in at 10.30 grams.

I used 21 ml of nitric 70% and 21 ml of distilled water. It took roughly 15-20 minutes to dissolve this with very little heat covered.




This is what i was left with 




Once it cooled i filtered it through a coffee filter and added a little distilled water to rinse the filter adding what amounted to 40 additional ml of water. You can see the distilled rinse water formed a light green cloudy division between the two layers? Could this be silver chloride? Is it possible my distilled water or coffee filter had chlorine contamination?

At this point i just stirred the liquid and went for the cementation process, this is a trial run after all.







I used a coil of copper ground wire new from a box and the silver began cementing out immediately. Took all of 5 minutes till it slowed down. I filtered this off and rinsed it 4 times with distilled water until the rinse was clear.





continued in next post


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## Gsracer

After i rinsed the cemented silver, i melted it into a button




the theoretical yeild was
90% coin 11.09 grams
92% spoon 9.52 grams for a total of 20.61 grams

My button came in at 17.84 grams so im at 86% recovered.

Now i know there is silver still cementing (see picture below) , im going to leave this over night. The solution is still light green and i understand it should be cobalt blue. im curious as to what could have occured when i added the distilled water in the picture in my first post and why the solution went from blue after dissoling to green in the first place. 

This is where it stand as of now, this will basically sit over night.






Any tips or criticism would be appreciated as well.

Thanks


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## Gsracer

oh one thing to add.

In the last picture, the rest of the solution im going to leave cementing overnight, i noticed there are quite a bit of black bits cementing out with the remaining silver in solution.

Could this be PGMs?

Thanks


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## Lino1406

"Cloudy" that is silver chloride. Green - copper chloride. What says the distilled water is not so distilled..no PGM, it would cement fiirst


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## Gsracer

So basically your telling me that my Winn Dixie brand distilled water is not really distilled. That was my guess too.

Anyway of being able to tell if the water in using is actually distilled short of making it myself? Any brands I should be looking for? 

Also what yield should I be expecting. I had read that <90% would be ideal.


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## nickvc

You can use tap water for silver refining but the trick is to add a little silver nitrate solution to your tap water stir it well and leave to settle, this will remove any chloride from the water so it’s ideal for silver recovery.


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## Gsracer

Well it looks like the rest dropped out over night. Better color. I’ll rinse dry and melt to a button to see what the final yield really was. 

I’ll also test to see if any silver remained in solution. 

What can I expect purity wise without running through a cell. 

Again this was a pure learning experience for me and practice. Mostly just to see if i could do it. Lol. I have learned a lot reading on here and it has been invaluable.


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## jmdlcar

Thank you for posting your first attempt. I will try and remember what you did so when I do my first attempt I will try and copy what you did. It will be awhile because it to cold outside to do anything right now. I will wait tell it gets 40 F outside before I try.


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## Martijn

The first silver that cemented will be fairly pure and less contaminated with copper than the last bit if i understood correctly.
You can add an air bubbler to get the very last bit out like in the stockpot. Keep silver nitrate wastes out of your normal stockpot because of HCL and AgCl forming.


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## Martijn

And to test if all copper nitrate is rinsed out of your cemented silver: add a couple of drops of ammonia to a test tube with a bit of the rinse water. If there's any blue showing, rinse some more.
Edited: forgot the word ammonia...


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## Gsracer

Martijn said:


> And to test if all copper nitrate is rinsed out of your cemented silver: add a couple of drops of ammonia to a test tube with a bit of the rinse water. If there's any blue showing, rinse some more.
> Edited: forgot the word ammonia...




Thank you for posting this, helped tremendously. I repeated the process this time doing that.

So since i had some succuess with the first attempt, i decided to run about 10 troy ounces through.

I began with 370.62 grams, this was a mixture of about 80 percent junk silver coins that where slick and 20 percent sterling, Plus some slag ive collected from my crucibles from when i melted sterling in the past.

I was able to process this at high heat with the beaker covered and in only required 360 ml of nitric and 370 ml of water. There was about 10 grams of material left after this completed.

I separated it into two beakers however i only took photos of 1 of them.




This time i took a copper ingot i had and used it for the cementation, worked pretty good, i think i will go with this method from here on out.







Here is my silver more or less dried, I need a buchner funnel, this is the most tedious part washing it and filtering the rinse water through a standard funnel. But the ammonia test of the rinse water posted above helped me out a lot to know when i was done. 







Here is the weight albeit i believe it was a little damp.


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## Gsracer

i threw in the button from the first attempt to get the bar over 10 troy ounces, and placed everything into a crucible.






Into the furnace it goes, took 10 minutes.




and my completed bar with one slight defect.  cant be perfect i guess.





All in all if you take out the 10 grams that didnt dissolve in the nitric the yeild is close to 88 %. Not terrible for mostly coins and a bit of sterling. I am sure there is silver in solution in my cobalt blue waste bucket. I might try to precipitate it out as silver chloride at a later date, but i need to read up more on that process. 

In either case i took a sterling bar i had and processed it this evening. Its cementing as we speak so ill have a better set of numbers for that one as i know exactly what went into it.

Cheers!


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## FrugalRefiner

When you use copper to cement silver, avoid having any of the copper outside of the solution. Have it all submerged. Copper above the solution can oxidize, then drop off into your silver cement, lowering the purity a bit.

Dave


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## Martijn

Glad i could help. And nice work. Great looking bar. 
Keep watching the thickness of that copper wire holding the bar up. Labglas don't like falling pieces of metal.
But why not run it through a silver cell? Do you have an xrf result of this bar?


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## kurtak

Gsracer

First of all I just want to say that for a beginner just starting out & learning you are doing an AWESOME job with your venture into processing silver --- clearly you have done (&/or been) doing your homework before just diving in - making a bunch of mistakes - then asking us to fix them --- so - job WELL DONE on doing your research FIRST & then setting your self up to do this right once you were ready to actually start working with the process :!:  

A couple of pointers as you move forward & start working in larger batches 

1) glassware is fine for doing small batch learning experiment's - but as you move up in batch size start using SS (stainless steel) SS works just fine for processing silver & you don't need to worry about breaking it like glass

2) as Dave pointed out - when cementing your silver you want the copper fully submerged in the solution - so get yourself some SS wire/rod to hang your copper from

3) to get complete cementing of the silver the silver nitrate needs to come in contact with the copper so you can't just let the copper sit in the solution - the solution needs to be stirred from time to time so that the solution further away from from the copper comes into contact with the copper (one reason for working with SS instead of glass) --- AND - as the cement builds up in the bottom of the beaker - it "traps" silver nitrate in the cemented silver & doesn't get to the copper - so - you can't just stir the solution - you have to stir the cement to bring the trapped silver nitrate up out of the cement in order for it to make contact with the copper

In other words - the stirring needs to be aggressive & done from time to time (again the reason for working out of SS instead of glass)

This set of SS pots will get you started - but when you get them you NEED to replace the rivets that hold the handles to the pots with SS screws as the handle rivets are aluminum

:arrow: www.harborfreight.com/stainless-steel-stock-pot-set-4-pc-60624.html?cid=paid_google|||60

use 1/16 inch SS TIG welding rod for hanging your copper - check with you local welding shop - they will likely give you (or sell for a few $) a couple rods --- 1/16 inch = about 14 gauge wire so good size for hanging your copper

:arrow: https://www.amazon.com/KUNWU-Stainless-Steel-Welding-ER308L/dp/B08F5F31RP/ref=asc_df_B

Here is a 21 inch SS spoon for $4.50 (good for stirring)

:arrow: https://www.restaurantsupply.com/winco-bhks-21-21-heavy-duty-solid-stainless-steel-basting-spoon?msc 

Kurt


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## Gsracer

Martijn said:


> Glad i could help. And nice work. Great looking bar.
> Keep watching the thickness of that copper wire holding the bar up. Labglas don't like falling pieces of metal.
> But why not run it through a silver cell? Do you have an xrf result of this bar?




I will eventually get to a cell, but ive been learning one part at a time. From melting and casting to refining and ultimately electro-refining. My LCS is a pretty nice guy, i will take my silver over there to have it checked but the ultimate goal is running this through a cell as you stated.



kurtak said:


> Gsracer
> 
> First of all I just want to say that for a beginner just starting out & learning you are doing an AWESOME job with your venture into processing silver --- clearly you have done (&/or been) doing your homework before just diving in - making a bunch of mistakes - then asking us to fix them --- so - job WELL DONE on doing your research FIRST & then setting your self up to do this right once you were ready to actually start working with the process :!:




Thank you for the feedback, i definitly read on here for months before i joined, of course i watched sreetips on youtube which is what got me really interested. Sorry to say it was premature feedback as you will see below this is a learning experience lol and i made a few very stupid mistakes. 




kurtak said:


> A couple of pointers as you move forward & start working in larger batches
> 
> 1) glassware is fine for doing small batch learning experiment's - but as you move up in batch size start using SS (stainless steel) SS works just fine for processing silver & you don't need to worry about breaking it like glass
> 
> 2) as Dave pointed out - when cementing your silver you want the copper fully submerged in the solution - so get yourself some SS wire/rod to hang your copper from
> 
> 3) to get complete cementing of the silver the silver nitrate needs to come in contact with the copper so you can't just let the copper sit in the solution - the solution needs to be stirred from time to time so that the solution further away from from the copper comes into contact with the copper (one reason for working with SS instead of glass) --- AND - as the cement builds up in the bottom of the beaker - it "traps" silver nitrate in the cemented silver & doesn't get to the copper - so - you can't just stir the solution - you have to stir the cement to bring the trapped silver nitrate up out of the cement in order for it to make contact with the copper
> 
> In other words - the stirring needs to be aggressive & done from time to time (again the reason for working out of SS instead of glass)
> 
> This set of SS pots will get you started - but when you get them you NEED to replace the rivets that hold the handles to the pots with SS screws as the handle rivets are aluminum
> 
> :arrow: www.harborfreight.com/stainless-steel-stock-pot-set-4-pc-60624.html?cid=paid_google|||60
> 
> use 1/16 inch SS TIG welding rod for hanging your copper - check with you local welding shop - they will likely give you (or sell for a few $) a couple rods --- 1/16 inch = about 14 gauge wire so good size for hanging your copper
> 
> :arrow: https://www.amazon.com/KUNWU-Stainless-Steel-Welding-ER308L/dp/B08F5F31RP/ref=asc_df_B
> 
> Here is a 21 inch SS spoon for $4.50 (good for stirring)
> 
> :arrow: https://www.restaurantsupply.com/winco-bhks-21-21-heavy-duty-solid-stainless-steel-basting-spoon?msc
> 
> Kurt




This is great info, and perfect timing as i was just going to order some larger beakers today. Would it be safe to assume i am able to dry the cement silver in a stainless steel pan, as i am having a large issue finding suitable pyroceram locally. This will be infinitely more convenient. I tig weld so i have plenty of 308L Stainless tig rod on hand. I have been stirring frequently and vigorously. I have only accumulated about 3.5 liters of waste from what i processed so far, i ran several tests with HCL from the waste pot but did not precipitate any silver chloride. So im pretty sure i got it all out.

Well that brings me to my problem.

My first two batches went off without a hitch. 

Batch 3 and 4 i made some very stupid mistakes.

Lets start with the easy one, or at least i think the easy one. 

Batch 3 

After i cemented all the silver, during my final rinses i noticed a brownish precipitate in the the rinse water. My sterling was 100 percent clean Sterling, with no iron of any kind. At first i thought this was iron contamination, because apparently i just dont trust the distilled water i am buying. So i continued along testing the rinse water with ammonia and not the slightest color change at all.

Precipitate in rinse water and cement








Well while i left this drying overnight, i pondered this in bed last night and when i woke up this morning i noticed it had a hit of green here and there. So i took a sample and dissolved it in a few ml of nitric and distilled water and bingo copper confirmation. I had just placed the copped bar in the beaker this time around and it came in contact with the cemented silver, i should have known this would contaminate everything. Plus with stirring i probably knocked a lot of copper.

sample of cemented powder with nitric and distilled water.





I guess i should just run this cemented silver through nitric again as this will be the easiest for me.



As for batch 4.

I had what i "thought" where 6 coin fiddleback spoons from the early 1800s, all 6 where identical but badly worn. I'm lucky had the foresight to run these on their own as i was not sure of the authenticity. I tested two of them with nitric and hcl. I grinded the bowl of the spoon with the dremel and tested with nitric and hcl and they where indeed silver. However i should have tested them all but i assumed since they where identical they would all be the same.

So i did my process, cut them into pieces, incenerated and started the reaction.

After a few minutes of digestion the reaction stalled, and stalled big time. Apparently two of the spoons where some type of plated brass i fished out those two. Well all the undigested pieces anyway. At this point there wasn't much to do so I Add a little bit more nitric and heat and continued on the process.

I was left with a forrest green solution which did indeed cement out some silver on the copper. So i now have what i assume is badly contaimated cemented silver. 

What would be the ideal step here. Process this small ammount seperatly agin through nitric and see where it goes? Chuck it up as a loss due to learning? lol.








I made two clear mistakes here, the first one im thinking i let the copper sit in the cemented silver but ill wait to see what you guys have to say. The second one i made an assumption, that one will not likely happen again.

This is definitely a learning process and i am thankful for this resource.

Jerry


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## nickvc

Please note what I posted earlier regarding your water there is no need to use distilled water just use tap water and add silver nitrate to it and stir well, allow to any chloride to settle, decant and or filter and you are good to go.
Any silver chloride can be collected and stored wet and converted when you have sufficient to bother with.

If you did put brass into your solution it really won’t matter too much it will consume more nitric but will cause no other problems.
If your aim is to produce 999 silver then a cell is a good route but you can get that from converting silver chloride to metallic silver with a little care especially with the rinses.


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## etack

You also need to coat your ceramic wool.


Eric


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## Gsracer

nickvc said:


> Please note what I posted earlier regarding your water there is no need to use distilled water just use tap water and add silver nitrate to it and stir well, allow to any chloride to settle, decant and or filter and you are good to go.
> Any silver chloride can be collected and stored wet and converted when you have sufficient to bother with.
> 
> If you did put brass into your solution it really won’t matter too much it will consume more nitric but will cause no other problems.
> If your aim is to produce 999 silver then a cell is a good route but you can get that from converting silver chloride to metallic silver with a little care especially with the rinses.





Great to know, as for the tap water, here where i live. We have a very high chlorine content in our tap water since we are at sea level, right next to the ocean, with a low water table Im afraid i would end up with a ton of silver chloride as well as other contaminants. I have not looked in depth at silver chloride conversion at this point since im just starting. But i will keep it in mind. Thank you.




etack said:


> You also need to coat your ceramic wool.
> 
> 
> Eric



You are absolutely right. I have some cement on order for it.


I was able to correct the issues with batch 3 and 4. I ran them through dilute nitric a second time and everything cemented cleanly.

I think im getting the hang of this now. I am testing rinse water with ammonia and hanging my copper with 308l tig wire in the middle of the solution being careful not to let it rest on the cemented silver.

I have to say these last two batches are the cleanest cement silver i have made thus far.

Pics of batch 3 and 4









Although i did notice in this picture the silver was indeed cementing on the stainless steel rod. 




Here is my clean cement


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## Martijn

That's gorgeous to look at. Nice job.


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## Gsracer

After drying it sat in my toaster over for couple of hours heres the weight dry.




For batch 3 
Its hard to make out but its 624.9, the weight of the empty vessal weighs in at 306.59 grams leaving me with 318.31 grams yeild. I started with 347.11 of clean sterling. Giving me a recovery of 91.7 %. Not to bad 

For batch 4 i can not calulate a yeild due to the fact that two of the spoons where brass. I poured a little bar with the cement i got from this batch pictured below.




I took this small bar and the 10 oz bar i poured above to my LCS who has an XRF. 

He tested the 10 oz bar and it came in at 99.92 AG 0.08 CU
The little bar that came from the dirty batch came in at 98.6 AG and 1.4 CU.

Not bad either all things considered. 

Also stopped at one of my favorite thrift stores and picked up my first piece of corningware, this should make my life easier.








Well the time has come, i have gotten enough cement silver to explore the electrolytic silver cell, so i have the parts coming and will begin construction this weekend.

Cheers


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## Gsracer

on to batch 5 , i stepped up the quantity this time to 500 grams of some ugly sterling bars i poured when i was learning to melt.




As per the steps, i melted this into shot and added a little bit of undigested shot from batch 4.




With the advice i have recieved this is the cement setup now, the stainless steel welding rod and some of my copper pours with some copper ground wire. I used new wire everytime i add it but the bar i grind the oxidation layer off.




and this is my filtered solution.




now i did not plan, nor was i expecting to digest all of the shot i poured but i added it anyway as i know its better to be left over with some undigested silver rather than free nitric in the solution. Its worth noting that 350ml of 70 percent nitric consumed quite a bit more sterling than i expected.

I started with 521.41 grams of shot, and i was left with 66.21 after i exhausted all the nitric in the reaction.

Basically 350ml 70% / 350ml distilled water ate 455.2 grams of sterling, or my 70% nitric is actually stronger.

The reaction vessel is covered and being heated of course.


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## Gsracer

As expected, since i consumed all the excess nitric in the reaction when i put in the copper for cementation nothing happened after a few minutes. So i added 2 ml of nitric and it took off. I had to step away for an hour but when i came back, something very interesting happened. I had beautiful crystals growing and a blue stripe within the solution from where all the silver was removed. Of course i stirred it and redistributed everything but it was indeed interesting. The pics where cool too.


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## jmdlcar

You said this.


> I started with 521.41 grams of shot, and i was left with 66.21 after i exhausted all the nitric in the reaction.
> 
> Basically 350ml 70% / 350ml distilled water ate 455.2 grams of sterling, or my 70% nitric is actually stronger.


Here how I would have did it. I had 350 grams of Sterling 350ml of distilled water and 420ml of 70% Nitric Acid.

Here is a link how to do it.

https://goldrefiningforum.com/phpBB3/download/file.php?id=44986


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## kurtak

jmdlcar said:


> You said this.
> 
> 
> 
> I started with 521.41 grams of shot, and i was left with 66.21 after i exhausted all the nitric in the reaction.
> 
> Basically 350ml 70% / 350ml distilled water ate 455.2 grams of sterling, or my 70% nitric is actually stronger.
> 
> 
> 
> Here how I would have did it. I had 350 grams of Sterling 350ml of distilled water and 420ml of 70% Nitric Acid.
> 
> Here is a link how to do it.
> 
> 
> 
> https://goldrefiningforum.com/phpBB3/download/file.php?id=44986
Click to expand...


Per the underlined -----------

There is no such thing as --- IT TAKES - or - YOU NEED --- x% (say 68 - 70 %) nitric to dissolve x amount (say 1 gram) of silver (or copper)

In other words - there is "no such thing" as an exact calculation of how much acid you need to dissolve an exact amount of metal

That is because how much acid to how much metal depends a great deal on the conditions involved in the dissolving of the metal --- in other words - depending on the conditions - it "may" take more acid - or - less acid to dissolve the amount of metal you are dissolving

I have posted about this a number of times in the past - here is a link to one such thread (which has a link to another one of my post on this subject)

:arrow: Dissolving the Copper in Sterling (nitric Qty?)

This is especially import to understand when making your electrolyte for your silver cell because you don't want to end up with "a lot" of free nitric in your electrolyte --- & for that matter you don't want to be wasting nitric because you are using "poor conditions" to dissolve your silver

Kurt


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## Lou

Kurt,

When we'd make up our electrolyte we'd always leave extra silver in the bottom in bar form. We'd start with a known quantity of dry cement, dissolve it, leave a bar in there to kill off excess nitric and then weigh the solution and titrate a 5.000 g sample of it in duplicate. 


GSracer, you might consider skipping the Cu reduction and going with the addition of HCl. If it were me, I'd pull a small sample of the pregnant (as in it's full of silver), *filtered* Ag solution and then I can test how much HCl it takes to precipitate 95% of the Ag. I don't even need to standardize the HCl. I would just take my concentrated stuff, dilute it down 10X and see how many drops it takes to precipitate a known mass or volume of that solution.

I don't want to precipitate _all_ of the Ag, just most of it:

AgNO3 + HCl = AgCl (precipitate) + HNO3

If I do not add overmuch HCl, I can reuse the nitric acid for dissolving more sterling and lower my unit cost per ounce. Also, adding an air bubbler to the reaction helps produce nitric acid in situ by the following reaction.

O2 + 4 NO2 + 2 H2O = 4 HNO3 
Once upon a time, a large company doing 40 tons of Ag per week in nitric was using a pressurized version of that reaction. 

If you then take the AgCl, you can cement it with much cheaper iron and sulfuric and some tumbling. This might not produce less liquid, but it certainly costs less in both nitric and copper and the silver metal obtained can be very high quality if washed with the right flux mixture!


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## jmdlcar

I am STOP saying or writing anything to anyone that write a message.


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## Martijn

jmdlcar said:


> I am STOP saying or writing anything to anyone that write a message.


No need for that sir. Sharing is caring and you have the best intentions to help and contribute. That's exactly what this forum is about. 
We correct (sm)all details so others that read this will not be misinformed. 
We never stop learning. None of us. Love this forum.

I have limited knowledge in this field being a hobbyist and have been learning by reading a lot and the corrections i got from members. 

Since these gentlemen gave me so much for free i want to give some back whenever i can about things i feel confident enough about to advise new members.
Next level things i leave alone for the jedi's. And they have said all of that basic stuff more than enough. 
Only when someone is lost or asks basic things I respond if no one else has. 
And i have been put in my place more than once. And i thank them for it. As long as it's polite and constructive. 
Martijn.


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## kurtak

Lou said:


> Kurt,
> 
> When we'd make up our electrolyte we'd always leave extra silver in the bottom in bar form. We'd start with a known quantity of dry cement, dissolve it, leave a bar in there to kill off excess nitric and then weigh the solution and titrate a 5.000 g sample of it in duplicate.



Lou

Not sure what your point is - but yes you can certainly make your electrolyte with cemented silver as the cement silver should be relatively low in copper (if done right) it is just my preference to use some of the crystals from my cell for my electrolyte - & yes you want to make sure there is some silver remaining when the reaction is "done" to insure there is no free nitric 

For what its worth - there are (only) a couple reasons why I even run my "small" silver cell

1) I have a silver buyer that pays me 5% over spot for my silver cell refined silver - he is a Hmong silver smith that makes ceremonial Hmong jewelry - the "true" Hmong traditional/ceremonial jewelry is made of 999 (plus) silver (not sterling) so he likes my silver cell silver 

2) I always end up getting a few large crystals when I run my cell - the crystals that run from 2.5 grams to 7 grams are picked out & sold as crystals because I am able to get 5 to 10 times spot for them depending on their size, shape &/or crystal structure

Other then that - sterling goes direct to a refinery as I get paid the same or 925 as I get paid for 999 so it doesn't make a lot of sense to spend the time & chem cost to refine it myself

lower grade &/or un-known silver (such as contact points or silver recovered from gold filled etc.) gets dissolved & cemented - poured to kilo bars - XRF'ed - & other then "some" of it run in my cell - it goes to the refiner for the same reason sterling goes to the refiner

Kurt


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## Gsracer

JMD, 

The point i was making (especially after reading numerous threads on the subject) is there is no set amount of nitric for dissolving silver. Especially if you are applying heat and have the reaction vessel covered. I have found on the 5 batches i have ran that it takes considerably less nitric to digest the silver. 

What i typically do is weigh the amount of metal i want to process, for the sake of numbers lets say 250 grams of sterling. I add 250ml of water, then 100 ml of nitric, cover, heat and see how the reaction goes. I typically add 50 ml at time watching the fume production towards the end i add 10 ml increments until i have just a little un reacted metal left on the bottom. This ensures no free nitric in the solution which will cause problems during cementation. Had i added the prescribed amount of nitric in the beginning. Each batch would have had a severe excess of nitric in solution. Just something to note when you start yourself. 


Kurt,

As to make your point, i dissolved 180 grams of silver cement mixed with 120 grams of 999 bullion coins in just 200 ml of nitric for my electrolyte.

Lou,

Im going to attempt to learn the silver chloride method when i process my waste bucket. That will be a learning curve for sure. But thanks for the info!


So to update, i have on hands 1680 grams of cement powder, and my supplies came in so time to build my silver cell.

I ordered the adjustable power supply and the stainless bowl, however i wanted to try something different. I had some 316 stainless plate from a previous project in the garage so i cut a piece to fit inside a 2000ml beaker, and tigged a 3/16 rod to the plate. I inuslated the rod with 2 layers of polyolefin heat shrink.










I used 120 grams of 999 silver bullion and 180 grams of my lightest cement powder to make the electrolyte. Giving me 150 g/l.




I poured a few small bars to use in my anode basket, the basket is made of 2 layers of walmart muslin cloth.


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## Gsracer

now before you say it, i know the cathode anode distance is further than the prescribed 4.5 inches. However i didnt realized that till moments before i hit "ON" at the power supply. However it was late so i figured what the hell. Im going to make a new cathode today to shorten the distance. I will also be pouring more cement shot to fill the basket as i also ran out of propane last night. The basket can easily fit 10 oz bars.

The cathode surface area is roughly 10.4 sq inches, and i was able to put 3.0 volts and 2.29 amps.

Here is a shot of the basket. Im already seeing black residue and decomposition in the anode basket.




This is the growth within a few minutes after turning the cell on




And here is after running for exactly 12 hours.


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## kurtak

jmdlcar said:


> I am STOP saying or writing anything to anyone that write a message.



jmdlcar 

I did not mean to offend you & am MOST CERTAINLY sorry if I did :!: 

Not sure where to even start here - but will try

You have been a member for about 10 years now - but based on your recent questions you are just beginning your first attempts in silver refining (so it's a learning process)

In one of your threads you asked the question - "how much nitric do I need to dissolve X amount of silver" ?

In reply to that Ralph (palladium) posted the link to the PDF acid work sheet - & there is nothing wrong with that PDF

Ralph is one of our "most respected" members (& a member I VERY MUCH respect) and those numbers posted in that PDF are true - BUT - they are only true "To a Point" --- in other words generally speaking those numbers are true - but they are not absolutely true --- that is because although generally speaking those numbers are true - the amount of actual amount of acid it will take to dissolve a given amount of metal can & WILL change based on the conditions under which the metal is being dissolved --- THAT is true whether you are dissolving gold, silver, copper or other (normally base) metals

In other words - those (PDF) numbers are a general "rule of thumb" but NOT an "absolute law"

Therefore - IF (the big IF) you follow those numbers as a absolute law - you will more often then not - find yourself wasting acid

That is because using those numbers "to the letter of the law" - you will find - that depending on the conditions used in dissolve a given batch of metal - more often then not - one of two things will more likely (then not) happen 

1) all your metal will NOT dissolve - so you will need to add more acid - which in turn means you are wasting acid

2) all your metal will dissolve BUT there will still be "free" acid left (so unless you have more metal to add - to use up that free acid) again you are wasting acid

Point # 2 (above) is one of the most common mistakes that new members run into when they dissolve gold with AR --- & then when they use to much nitric in their AR they can't get their gold back (the gold wont drop back out of the AR) so we end up telling them that "their problem" is to much free nitric in the AR so they need to de-NOx the AR to remove the free nitric before their gold will drop

The reason that they end up with free nitric in their AR is because before coming here to the forum - they find info elsewhere on the internet with a "general rule of thumb" for dissolving gold

The general rule of thumb - for dissolving gold - is to use 1 ml 70% nitric with 3 ml HCl to dissolve 1 gram of gold - and that "MAY'" be close to true if you are trying to dissolve a solid gold coin

However - more often then not - they are dissolving gold foils recovered from a batch fingers - & that changes the condition of dissolving the gold --- in other words - there is a difference between dissolving a one ozt gold coin & dissolving one ozt of gold foils

That difference (which is a condition) is surface area --- an ozt of gold foils has MUCH more surface area then a solid gold coin

Therefore - because the gold foils are VERY thin with LOTS of surface area - the acid does not need to work anywhere near as hard to dissolve the gold - which in turn means it WONT take as much acid to dissolve the gold - compared to dissolving a sold gold coin - which in turn means if you use the "rule of thumb" (1/3 nitric/HCL to dissolve a gram gold) to dissolve gold foils - you ARE going to end up with with free nitric in your AR - which then means you have to de-NOx the AR to get rid of the free nitric - or your gold will not drop - which in turn means you wasted acid in the first place

The same holds true whether you are dissolving gold, silver, copper or some other metal 

How much acid it takes to dissolve a given amount of metal WILL change depending on the conditions under which you are dissolving the metal --- in other words - depending on conditions - it may take more acid - or it may take less acid - then the (so called) rule of thumb numbers 

the bottom line is that if you follow the rule of thumb numbers - as an absolute law (as in IT TAKES) you will in fact find yourself wasting acid

Therefore - once you understand how conditions effect the amount of acid you need to dissolve a given amount of metal - you can use those conditions to your advantage - so you need to understand the conditions that effect the actual amount of acid it will take to dissolve a batch of metal (& there is NO absolute here - it is "a bit" of a guessing game with each batch)

1) surface area - it takes more acid to dissolve (say) a solid kilo bar of silver then it take if you dissolve (say) that same kilo of silver melted & pour to silver shot --- that's because by pouring the silver to shot you create a whole "lot" more surface area - so the acid does not have to work as hard at dissolving the silver - so you will use less acid

2) dissolving the metal in a closed vessel compared to dissolving the metal in an open vessel - if you dissolve the metal in an open vessel (no cover on the beaker/bucket or pot) it will take more acid then if you put a cover on the vessel - that's because by keeping the NOx in the beaker (or vessel) helps get more use of the acid as "some" of that NOx gets re-absorbed back into the solution during the reaction - instead of letting all the NOx go out the top of the beaker

3) when dissolving silver (or copper) - if you use about half again the (so called) recommended amount of water (distilled) you will get better use of the acid - that's because the NOx stays in the solution better (in stead of just gassing off) thereby you will get more full use of the acid during the reaction

4) Heat makes a difference - to little (or no) heat makes the acid work harder (not the same as - but kind of like surface area effects acid consumption) & on the other hand to much heat will cause NOx to be driven out of the solution during the reaction --- therefore you can start out with your batch on the hot plate to get the reaction started - once it is getting going but not full blown - turn the heat off & the heat of the reaction will do its own thing - then when the reaction is slowing down - turn the heat back on until you are done with the batch --- this will give you better use of your acid

Taking into consideration & using these conditions - I have dissolved successfully (although only a couple times) as much as 500 grams silver with only 350 ml 68% nitric (so .7 ml acid per gram silver - that's 5 tenths of a ml less acid then the "recommended" 1.2 ml acid per gram) 

On the average (so sometimes more & sometimes less) - using those conditions to my advantage - I would be willing to say I get away with using only about .9 ml of 68% nitric per gram of silver when doing a batch of silver

To put that in perspective - when I make my electrolyte for my silver cell - I do it in 500 gram (silver) batches - on the "average" I am able to dissolve that 500 grams with "about" 450 ml 68% nitric --- so on a 500 gram batch I am saving "about" 150 ml of nitric --- in other words - according to the rule of thumb - in theory - it should take 600 ml acid to dissolve 500 grams silver - but on average I get away with only "about" 450 ml acid

My point in all of this is that the PDF Ralph posted is actually only a rule of thumb (not an absolute law) - therefore - as a rule of thumb - depending on conditions - it may take more acid - or less acid then the rule to dissolve a given amount of metal --- & IF you use those conditions to your advantage you can almost always (if not always) get away with less acid

Kurt


----------



## kurtak

Gsracer

Read what I posted concerning anode bags in this thread as well as Lou's comment to what I posted

 :arrow: Copper cell

also for a small cell read this

:arrow: Can only get coral like silver crystals

Kurt


----------



## jmdlcar

First off I know I been here 10 years now and I started with Gold because it didn't take much to get $$$ but some one wanted more them me and they took it. It was 10grams I did. So I just quit doing it.

Now what happen now I wanted to start over but this time I went with Sterling Silver that's why I ask this question "how much nitric do I need to dissolve X amount of silver" to get a idea so I would get a idea.

So I quest when I do my first batch and have 200 grams of Sterling I would use 200 ml of Distilled water and start with 50ml of 70% Nitric Acid then add 50ml tell I get to 100ml and then I go to 10ml if then I have a little Sterling left I will stop. I wanted to do it right so I wouldn't have any waste.

I have my equipment when I did Gold but I did buy a Stainless Steel 304 2 quart stock pot to process the Sterling Silver and copper to cement the Silver. I know 2qt stock pot is no big but I won't process more then 200 grams at a time Nitric Acid.

Then I will do a Silver Cell it get 999 I hope.


----------



## Gsracer

jmdlcar said:


> First off I know I been here 10 years now and I started with Gold because it didn't take much to get $$$ but some one wanted more them me and they took it. It was 10grams I did. So I just quit doing it.
> 
> Now what happen now I wanted to start over but this time I went with Sterling Silver that's why I ask this question "how much nitric do I need to dissolve X amount of silver" to get a idea so I would get a idea.
> 
> So I quest when I do my first batch and have 200 grams of Sterling I would use 200 ml of Distilled water and start with 50ml of 70% Nitric Acid then add 50ml tell I get to 100ml and then I go to 10ml if then I have a little Sterling left I will stop. I wanted to do it right so I wouldn't have any waste.
> 
> I have my equipment when I did Gold but I did buy a Stainless Steel 304 2 quart stock pot to process the Sterling Silver and copper to cement the Silver. I know 2qt stock pot is no big but I won't process more then 200 grams at a time Nitric Acid.
> 
> Then I will do a Silver Cell it get 999 I hope.





That's exactly what i would do. Just watch the fume production.




kurtak said:


> Gsracer
> 
> Read what I posted concerning anode bags in this thread as well as Lou's comment to what I posted
> 
> :arrow: Copper cell
> 
> also for a small cell read this
> 
> :arrow: Can only get coral like silver crystals
> 
> Kurt




Kurt i did read both of those threads.

This is the cloth i purchased



Robot or human?



But i think i got the wrong one, see below.

Well this morning this is what it looked like.




I started making my different cathode for my beaker, i went with a slighlty different design. Half circle and lighter weight so i can suspend it closer to the anode basket. And it would have space so when i would knock down the crystals they would fall to the bottom and hopefully allow me to run the cell for longer period of time. It is not at 4.5 inches below the anode basket. It gives me a surface area of 7.92 inches.





So i began dissembling the cell to harvest and change out the cathode. This is what my anodes looked like when i removed them.

And the sludge in the basket.







However when i removed the basket i placed on another beaker, i noticed the sludge was dripping through into the basket. The cell itself was completly clean with no residue this only happened when i moved the basket. Is it possible the cloth i have is the incorrect one or my basket has to many / to large of holes?





In either case , i filtered my electroylite and placed a new doubled muslin cloth filter in there and started it back up.


----------



## Gsracer

With in minutes of starting.





After running for just over two hours.






This is the dried silver cell from running for 14 hours. 141.1 grams or 4.56 troy oz not incuding the beaker.

It sure is pretty. the picture does not do it justice really, although im worried it could be contaminated from the issue i posted above.

Critiques , thoughts welcome


----------



## jmdlcar

For me the second one look a lot clear and a lot better to. That another item I need to buy to filter Silver.


----------



## jmdlcar

Can someone tell me what cause the sludge in this picture?
https://goldrefiningforum.com/phpBB3/download/file.php?id=45435&t=1


----------



## Lou

*jmdlcar:
*
In my experience it is Ag2O.


----------



## Gsracer

Just to update, this cathode seems to be running more efficiently.

With the previous cathode thickness and spacing i could get 3.49 volts @ 2.49 amps.

With this new thinner and closer cathode im running at 3.49 volts @ 2.56 amps.

So i figured i was going to need more silver to run through. I melted 15.26 troy ounce to run. Instead of bars i decided to use shot this time.




Interesting comparison from left to right

sterling shot for digestion, cement silver shot, silver crystal from the cell.




about 20 ounces in the basket, once i poured the shot something interesting happened. The amps went from 2.56 amps to 3.38 amps at 3.49 volts.







growth at hour 5


----------



## Gsracer

at hour 12, a large growth occurred and the amps shot way up to 4.22, i knocked it down and lowered the voltage for the night. Lets see what it looks like in the morning

Here is the electrolyte temp.




The growth and power supply pictures


----------



## jmdlcar

@Gsracer, Which one did you at Walmart muslin can I have the link? The cathode how thick is the 304 Stainless Steel? I found one 0.05" thick, 0.104" thick and another one 3/16" thick.


----------



## Gsracer

jmdlcar said:


> @Gsracer, Which one did you at Walmart muslin can I have the link? The cathode how thick is the 304 Stainless Steel? I found one 0.05" thick, 0.104" thick and another one 3/16" thick.



Jmd,

This is the muslin im using however id wait till we get some feedback from more experienced users due to the issues i described above.

https://www.walmart.com/ip/Waverly-Inspirations-100-Cotton-44-x-2-Yards-Precut-Natural-Muslin-Fabric-1-Each/49332641

As for the stainless im currently using, it is a piece of 304 stainless exhaust tubing i had laying around, i split it with a angle grinder and hammered it flat, then i cut it and shaped it with the angle grinder. Id say its about 14 gauge thick.


----------



## jmdlcar

I have a 4 x 6" SS 304 20ga do you think it to thin to use?


----------



## Lou

@GSracer,

The voltage decreases the shorter the anode to cathode gap is. The amps increase, the closer the anode to cathode gap is. The electrons move more easily. Likewise, with your shot, the amps went up because you had more surface area.

You must be vigilant that you don't short the cell, so periodically you have to knock it down. In a "production" Thum cell I once had six of, we used a 30"x60" piece of CP Grade 2 titanium that was 16 gauge. We bolted buss bar to the top of them. 


*answer to jmdlcar question about cloth*:

That should be fine.

I had a small cell made out of a hotel stainless pan I used for parting remelts with high Au (from burning anode bags) and I used muslin from Jo ann fabrics, 2 layers, but the pan couldn't have been any thicker than 1/16th of an inch which I believe is 20 gauge.

https://www.webstaurantstore.com/52489/stainless-steel-steam-table-pans-and-hotel-pans.html

Anyone setting up cells, have a look at this link I highly recommend them. You can use 3M plater's tape to keep the crystals from growing on the side. I used the plastic steam insert that sat right inside the pan. 

It's been a few years but I believe they run at about 35-45 amps/square foot and 3-3.2 VDC with a 3.5" anode to cathode spacing. I made a couple of these kits and sent them to a few members here about six years ago. 


Happy silver refining.


----------



## Gsracer

jmdlcar said:


> I have a 4 x 6" SS 304 20ga do you think it to thin to use?



As lou said, i believe so, the cathode should not degrade at all.




Lou said:


> @GSracer,
> 
> The voltage decreases the shorter the anode to cathode gap is. The amps increase, the closer the anode to cathode gap is. The electrons move more easily. Likewise, with your shot, the amps went up because you had more surface area.
> 
> You must be vigilant that you don't short the cell, so periodically you have to knock it down. In a "production" Thum cell I once had six of, we used a 30"x60" piece of CP Grade 2 titanium that was 16 gauge. We bolted buss bar to the top of them.



Yes i noticed that when moving the cathode in the solution as well. Ive been playing around with amperage today. And have gotten some pretty large crystals, pictures coming soon as i dont want to disturb the table too much right now to get close ups.

Basically ive found that if i turn up the volts to 3.5, i can push 3.4 amps. I ran this way for an hour and of course got long feathery growths fairly quickly. Then i backed off the volts till i received 1.9 amps for 3 hours and the feathery crystals have filled in and gotten much thicker. 

Basically I've noticed that the higher amps causes new branches to grow. Then when i back off the amps the branches fill in and i do not get new growth. I'm going to run a couple cycles like this today and post the results later in the evening.

Also ive read that i can gauge the color of the electrolyte when its depleted. Mine is still a pale blue but i have noticed its gotten slightly darker. I obviously dont think it should get cobalt blue like when your cementing silver. I started with pretty clean electrolyte and have been running nothing but fairly clean cement silver. Is there any other way of empirically determining, given for a home refiner, or should i just change it out when it gets a little darker?

Regards.


----------



## jmdlcar

@Gsracer, I should have said in the last message I wrote your last cell look great and good job.


----------



## Gsracer

jmdlcar said:


> @Gsracer, I should have said in the last message I wrote your last cell look great and good job.



Thanks man, its appreciated, much hard work and research to get here.

Here is some pictures of my crystal growth at roughly 30 hrs.

The cell has eaten about 10 -12 troy ounces of cement silver shot during this time. I alternated between 3.5 amps and 2 amps as i stated above during the last 12 hours and got some pretty large growth.

Pictures do not do this justice to be honest, i can literally watch this thing grow all day.









I had to knock down the crystal for the night as i was worried it would hit the basket over night, i also dropped the amperage down to 1.75 for the rest of the night




and here is my electrolyte color, it has indeed darkened. I think after another 10 troy ounces go through the basket it might be time to change.

Id really like to hear the thoughts of the pros on this one, as when it comes to co-depositing point, im out of my depth.

Thanks as always.


----------



## jmdlcar

Do you still get sludge?


----------



## jmdlcar

In this picture how did you hook the Stainless Steel wire to the Stainless Steel Plate?


----------



## Gsracer

jmdlcar said:


> Do you still get sludge?



Yes, the sludge is going to occur always as those are the undigested parts of the anode. It could be platinum, gold, palladium etc. They are called slimes here on the forum



jmdlcar said:


> In this picture how did you hook the Stainless Steel wire to the Stainless Steel Plate?




I welded it directly to the plate.

To update.

I searched the forum high and low for the copper concentration in the electroylte. It seems that the concencus is somewhere between 40-60 grams per liter. Palladiums video on youtube went through this step by step however i dont know how he got to the numbers. Not saying they are wrong or anything. In either case i had no real way of quantifying this in my electrolyte.

Then i found an old post from frugal refiner which im quoting here.



FrugalRefiner said:


> Thanks Lino. I already do a similar thing. I created some 100g./liter copper nitrate, then did successive dilutions, saving small samples along the way. I have some small sample vials with the varying concentrations and I compare them to the electrolyte in the cell. Other contaminants can affect the color, but since I process primarily sterling, copper predominates. It's close enough to let me know when the copper is getting high.
> 
> Dave




This seemed like a feasbile option for me so i did just that. I dissolved 5 grams in copper and went diluting and saving samples to make a known quantities of CU in solution. It was a good idea and seems like a way to make a best guess.







Judging from the samples it seems my electrolyte is sitting somewhere in between 10-20 grams per liter. Im thinking when it gets closer to the 30-40 g/l range ill change it out just to be safe. Judging by the rate ive been feeding it, i should be able to get about 40-45 troy ounces through it. 


Also some pics from todays growth, since the electrolyte is already showing some copper i am limiting it to 3.00 volts which is producing 2.96 amps. This really is the coolest.


----------



## FrugalRefiner

When using the color comparison method, put a sample of your electrolyte into a test tube like your color samples. The color in your beaker will appear darker because of the greater volume of solution. A sample in a test tube will be more consistent with your color comparison samples.

Dave


----------



## Gsracer

Great suggestion! Thank you Sir! Upon doing your recommendation it is much closer to 10g/l if not less. Which is more inline given the amount of silver i have run through and the general cleanliness of my cement. Guess ill be able to reuse it for the next run!


----------



## Gsracer

So today I spent far to long having to push down the crystals before them hitting the basket. So it became harvest day.

Some highlights







Since i sanded the stainless cathode to 600 grit when i made it, the crystals literally came right off with no scraping required. No anode slimes drained this time from the basket when i lifted it. The crystals where washed in boiling distilled water 6 times until no silver chloride appeared with some drops of HCL in the wash water.

Pictures really dont do justice







Final yield, was 792.3 grams or 25.47 troy ounces not including the beaker, for exactly 4 days of operation. I averaged 1.75 at night and 3 amps during the day. As i have read, a silver cell should deposit about 4 grams per amp per hour. Based off my results i got an average of 8.25 grams per hour. So thats in line with what you guys expect.





Additionally based of off 98 percent cement purity i probably put 17.7 grams of copper into the solution which is roughly 8.85 g/l. The color of my solution is about to the 10 g/l so that matches up as well. Meaning the electrolyte should still be good. As a result I already restarted the cell. Filtered the electrolyte, and changed the basket filter. So its back in production. 

Cheers!


----------



## jmdlcar

Did you use this when you process the shots in Nitric Acid? If you did what was the temp?
https://goldrefiningforum.com/phpBB3/download/file.php?id=45446&t=1

I have one and I want to check the temp.


----------



## Gsracer

JMD, i keep the temp of the reaction between 165-175 deg f during the reaction and around 190 towards the end to boil off any remaining nitric.

To UPdate, the cell has produced 64 troy ounces of silver to date and i have had to harvest 3 times already.

Last good harvest











Running out of space









After this batch, i knew my electrolyte was getting depleted, as my silver crystals began to look very stringy, like steel wool, also the copper content was climbing in the electrolyte. So i decided to do a test and run the worst batch of cemented shot i had through the cell. I ran a little over 10 troy ounces of this probably 95-96 percent shot through the cell and this crystal would be used for my next electrolyte.

Continued in next post.


----------



## Gsracer

This shot came from very dark cement that had become contaminated with copper during cementation.

Here is what it looked like.




Once run through the cell, like i had said the crsytalls resembled moss balls and steel wool. As i expected with my depleted electrolyte.

I ran through the 10 ounces in a little over two days. This was the harvested crystal. Like powder.




I measured out 300 grams of it for my electrolyte and dissolved it in around 260 ml of dilute nitric acid.

To my surprise i was left with a pale yellow transparent solution of silver nitrate. Indicating that my cell was not as contaminated as i thought and yielded high purity crystals. I could have probably gotten by with just replenishing some silver nitrate for another 30-40 troy ounces through it. But better safe than sorry.

I ran the reaction till i had no excess nitric, the bar in the pics was added at the end jsut to make sure all the nitric had been consumed. Ive used this bar at the end of my electrolyte always to be sure. I ended up with 280g of electrolyte to which i added distilled rinse water i have used only for rinsing silver crystals removed from the cell in order to make 2 liters giving me a final value of 140g/l.





Here it is up and running again with 20 troy ounces of cemented shot in the basket.


----------



## jmdlcar

Gsracer said:


> JMD, i keep the temp of the reaction between 165-175 deg f during the reaction and around 190 towards the end to boil off any remaining nitric.



I will get out my hot plate and put my beaker in a glass dish then set it on the hot plate with water and see where I need to set it to get 165 to 175 F. Then when I do my first run I will know where to set it.


----------



## Gsracer

Just be careful when adding nitric at those temperatures as it can cause a boil over. If I need to add more nitric during the dissolving process I bring the temp down to below 150 and add it slowly 10ml at time waiting to see how the reaction responds. Then when I’m done adding I bring the temperature back up. 

This has worked for me, the pros might have a better way of doing it.


----------



## jmdlcar

I will not turn on the temperatures tell I add the shots then distilled water then Nitric Acid then the heat.


----------



## Gsracer

So i wanted to update, my little silver cell has processed just about 4000 grams of cement silver. Obviously there have been several electrolyte changes. I have probably changed it to conservatively. However it is definitely a work horse producing about 5 troy ounces a day when in service.

I have learned several things along the way. One think i learned is that i lose about 20 percent of the silver in my electrolyte after a run of about 40 troy ounces. 

Another thing is that my anode to cathode ration after i took detailed measurements is closer to 1.2 - 1 then the recommended 2- 1 ratio. This is probably why i could really get some amps in this thing. Once i had some growth i could get close to 4 amps at 3.5 volts which caused me to have to monitor the cell, and turn it down to .90 volts at 1.1 amps in the evening for risk of it shorting out.

Also i learned that the size of the holes in the anode basket vs the ammount of holes has more of an effect on amperage thats able to flow.

Heres some pics of a few highlights.

What i really liked about this design is that when the crystals grew high, i could knock them down under the cathode to let them start growing again and run more silver before cleaning it out.

Ive grown some really cool looking crystals which ive seperated from the main batch and i will post some pics later.


----------



## Gsracer

So after this last harvest i wanted to try something a little different, I wanted to build something closer in line with the recommended values and see if that would affect crystal growth.

I started with a plastic jar for the anode that's 2.75 inches giving me an area of 5.94 sq inches

Then i used a 316 stainless washer for the cathode with a 2.1 inch hole and a 4.5 inch diameter giving me an area of 12.44.

To this i welded 2 stainless insulated bars for the electrical connection and also to hold it up as the washer is heavier then the previous plate.

This would give me the recommended ratio of 2-1 and still give me the ability to knock down the crystals and extend harvest time. Also given that larger crystals tend to grow on edges, i thought this would maximize the edges available for large crystal growth giving the round shape.

heres what it looked like.




With this setup i definitely noticed i could not get the amperage where it was with the previous oversized anode basket. Most i could get was 3.5 volts at 2.5 amps but ive been running it at 3.0 volts with 1.98 amps.

The crystal growth after 18 hours seems denser than my previous setup




At around 20 hours i have a huge dagger like crystal that emerged, pictured below




more to come with results of this experiment.


----------



## kurtak

Looks like you are are having fun & learning a lot along the way :mrgreen: 8) :G 

Kurt


----------



## Gsracer

kurtak said:


> Looks like you are are having fun & learning a lot along the way :mrgreen: 8) :G
> 
> Kurt




Thanks Kurt, i indeed am having a great time with this project. There are just so many variables it makes it hard to keep track.

To update the Cell has been in operation for 9 days. I speculate i have just under 40 troy oz of silver in here.

I have replenished the electrolyte with some silver nitrate from time to time when evaporation has lowered the level. I started with 150 g/l giving me a total of 300 grams in solution. I replenished at day 4 with 30g diluted in 100ml and today with 40 grams diluted in 100ml.

This cell design has produced some of the most dense crystal i have been able to produce, some are rock hard and some are of the thicker crystalline type. I still have about 10 troy ounces of cement shot id like to run through it before harvesting. However i am seriously worried about the beaker given the weight of what's in here. I may run it for a day or to more and see how it goes. The cathode can still move in the beaker so its not wedged in or anything like that. Ive already knocked down quite about through the whole in the middle.

Here are some pics

Day 4 








Day 8












More pics to come of this harvest


----------



## Gsracer

So i was forced to harvest last night, I was in fear of the beaker breaking. I have never let it run this length of time. But it sure produced some nice ones.

Another thing i like about the 2L beaker is i can interchange. I drain and filter the electrolyte and it goes right back in service in a different beaker while i can rinse and dry at my leisure.








Here is the dried crystal picking out some nice ones to save.


----------



## Gsracer

and here are my pickers.

Some really nice ones, very chunky and not fragile. Some weighed in at 4 grams

Most in the 1-3 gram range







And the final weight, i had predicted earlier just at 40 Troy onces

I came in at 1228.2 Grams or 39.49 Troy ounces

This cell is not as fast as the other design but it produces way nicer crystals!


----------



## Inter Refiner

Hello friends,

I dissolved silver, copper and lead in nitric acid, 
Then I wanted to precipitate lead as lead sulfate before I precipitate silver chloride, I used sodium sulfate to precipitate lead.
My question is: Does silver precipitate also as silver sulfate through this process??

Thank you


----------



## butcher

silver sulfate is not very soluble at all.

If your silver has a lot of lead to begin with, you may consider adding a scorification and cupellation step, into the existing melting process of your silver, using bone ash powder or dish or an magnesium oxide cupel to absorb the lead and other metal oxides from the silver...


----------



## Inter Refiner

butcher said:


> silver sulfate is not very soluble at all.
> 
> If your silver has a lot of lead to begin with, you may consider adding a scorification and cupellation step, into the existing melting process of your silver, using bone ash powder or dish or an magnesium oxide cupel to absorb the lead and other metal oxides from the silver...


Can silver sulfate be transformed into chloride?,
I put the silver and lead sulfate in aqua regia but nothing notable happened, what would hav happened? 
And now how to get my silver back from their?

Thank you


----------



## butcher

Acids like metals seem to have some type of order or reactivity to them.

Just as in evaporating down of a solution of different acids, each has a different volatility, with water being the first and most volatile, then HNO3, then HCl, and on to sulfuric which is the least volatile and the highest boiling point of the acids. 

It is normally easier to convert metal salts in a similar order, although oxides of metals are fairly easy to convert to nitrates chlorides and sulfates, it is generally easier to convert nitrates to chlorides (than chlorides to nitrates), nitrates to sulfates (than it is to convert sulfates to nitrates) and chlorides to sulfates, (much more difficult to convert sulfates to chlorides).
Heating a solution with the acid (adding energy) and evaporation or driving off the more volatile acid often helps in the conversion.

Of course we may have other factors to deal with ,for example solubility's of the metals or their salts...

Can we go backwards, change a sulfate to a nitrate or a chloride?

Yes, but it is not as easy and often takes a highly oxidizing solution to do so.

You may not notice a change in these salts in the highly oxidized solution of aqua regia, that is if they did change.
Lead sulfate is fairly insoluble in aqua regia, silver chloride is insoluble in the aqua regia.


----------



## Lino1406

Here is my route: precipitate both AgCl and PbCl2. Dissolve PbCl2 with hot water and decant


----------



## Gsracer

So to update, ive been continuing this process over the year until i ran out of sterling.

Well i ammassed a good ammount i started processing again and now have over 10kilos of cement silver i wanted to run. Given my experience with my previous 2liter cell, which would produce roughly 1500 grams in 10 days. it would take me close to 7-8 weeks to process this batch. I decided that i wanted to build a larger cell i could potentially run more amps through and thus process the silver quickly.

Silver cell 3.0

Although the stainless bowl works for many, im just not a fan of it. Part of this for me is the silver, another part is the experience and learning portion.

After searching through threads and design ideas i found one that peaked my interest and decided to build it.

If he sees it he will know its his 

Starting out with a old thick walled wet cell battery jar, running 4Liters of electrolyte probably 125-150 grams per liter of silver crystal to start.

I had a 316 stainless 3/16 thick plate cut out today 9 x 5.25 for the cathode giving me a cathode area of 47.25 square inches, almost 3 times the cathode area of my previous cell. I have a 316 stainless 1/4 rod that i will be welding to the plate and insulating with some polyolefin heat shrink. And a bolt with wing nut will be welded to it for the wire termination.

Im still on the fence for the anode basket, im think i may go with some kilo size anode bars for this as it will help keeping the mess down with the slimes.

Im pretty sure i will max out my 10 amp power supply with this design but we shall see

Anyone who has any thoughts or criticisms or advise feel free

Pics









With my math i should be able to conservatively process between 3-5 kilos of silver on this electrolyte and able to process about 3000 grams in 10 days effectively doubling my previous cell.

Again someone correct me if you think im way off, obviously until i get it in service and see where the amperage ends up this is pure speculation. But given my experience with my previous cell i would think i should be able to get at least 4 amps per hour into this one.


----------



## snoman701

Ha...I have the same battery box. Only mine is about 1/4 full of silver crystals from last year. 

You should probably begin thinking about how you are going to empty it. I siphon. It's heavier and a little awkward to pour from.


----------



## Gsracer

snoman701 said:


> Ha...I have the same battery box. Only mine is about 1/4 full of silver crystals from last year.
> 
> You should probably begin thinking about how you are going to empty it. I siphon. It's heavier and a little awkward to pour from.


I was thinking the same thing. Regarding the siphon. 

What kind of amperage are you getting into it? Is your cathode configuration more or less the same?


----------



## delboy9891

That looks nice, Im still learning at the moment so some good tips there, I plan on using the sugar and lye method but not ready yet and thats a nice bar you poured, very impressive for a first attempt, hope I have the same success at my first attempt


----------



## orvi

Very nice work


----------



## snoman701

Gsracer said:


> I was thinking the same thing. Regarding the siphon.
> 
> What kind of amperage are you getting into it? Is your cathode configuration more or less the same?


I honestly don't remember. I used a piece of perforated stainless as the cathode, just because it was handy. I used a tupperware container from the grocery store that I cut the bottom out of. It was some weird one that had a plastic grate in the bottom to keep things fresh. So I used the grate to hold the weight of the anodes. I need to get it set back up here soon, but have to find a way to ventilate it so I can put it in my office.


----------



## silver1

Amount of silver in X amount of time is solely dependent on amperage. Amperage is dependent on cathode area and current density along with anode area. Two recommendations. You can use glass, stainless, but also HDPE. Find a rectangular box and you can use it. Next instead of using a large plate use multiple plates with closer spacing to increase current density. That way you can pull the maximum amps.

10 Kilo = 22lbs = 22 lbs x 454 grams = 9988 grams
Silver deposited = 4 grams/amp hr. 
10 amps input = 40 grams/hr.
9988/40= 250 hrs. 250 hrs/24 hrs per day = 10.5 days!


----------



## Gsracer

Thats my math as well, my goal with this cell is not to do it as fast as possible more so faster than i was doing it before. This is an hobby for me to keep my occupied lol.

However, the design you mention is intriguing. Would you happen to have any pictures? I assume the plates would be hanging or suspended vertically? I would also imagine that there would need to be some sort of flow in that design to minimize depletion at the cathode?

While we are on the subject of flow.

What's everyone's though of using a small aquarium bubbler to get some movement of the electrolyte outside of normal convection currents?


----------



## silver1

Gsracer said:


> Thats my math as well, my goal with this cell is not to do it as fast as possible more so faster than i was doing it before. This is an hobby for me to keep my occupied lol.
> 
> However, the design you mention is intriguing. Would you happen to have any pictures? I assume the plates would be hanging or suspended vertically? I would also imagine that there would need to be some sort of flow in that design to minimize depletion at the cathode?
> 
> While we are on the subject of flow.
> 
> What's everyone's though of using a small aquarium bubbler to get some movement of the electrolyte outside of normal convection currents?


Air agitation will work sir. Here is a pdf that will show a set up with the anode cathode set up.


----------



## Gsracer

Interesting design and good read. Thank you. I think i can build something like that. I am going to move forward with 3.0 design. As i already have all the parts cut and ready to weld them together this weekend. I will then mock up the other one and run that design when i break the cell down.

Thank you!


----------



## silver1

Anode bags for small scale bars.


https://www.hobbylobby.com/Crafts-Hobbies/Candle-Soap-Making/Soap-Making-Supplies/Muslin-Cotton-Bath-Tea-Bags/p/80935597


----------



## Gsracer

Thank you sir, ill definitely check those out.

Well i finally had a few hours to start working on the cell 3.0.

First i sanded the edges of the cathode plate and rounded the corners with 500 grit.

Then i drilled a whole and tig welded the 1/4 rod from both sides for a good electrical connection.






Next i added two layers of thick heat shrink to insulate the rod, after that i bent it over the edge of the rim of the glass vessel. To this i welded a stainless bolt with a butterfly nut so that i can connect and disconnect the ground lug easier.












Here is it all together.








I picked up two baskets today for the anode, the top one is made of polypropolene which i know will be fine in the nitric.

However the bottom one is a little thicker and really the one i prefer however its made from PET. From the PET MSDS that i can find it says its fine in nitric up to 30% concentration. I would imagine since most if not all of the free nitric in my electrolyte will be consumed i should be ok for using this one. Any reason why not to use PET in this application?

Also below is the cell filled with tap water to get an idea of capacity.

The lower line is 4 inches from the cathode. The top one is 4.5 inches distance from the cathode. With the water at the top line it takes 4 liters. So this will be a 4 Liter cell.


Thank you for looking.


----------



## orvi

In regards of PET, it is an ester. Esters are reactive chemicals, which could hydrolyze in acidic or basic enviroment. Bases are much more harsh for PET than acids. But still. 
In the cell, PET is soaked for pretty long time, some acidity is there, and this rise the possibility of leaching some short chain polymers to your cell. It could be completely OK, but sometimes, this could be detrimental - as they can interfere with crystal growth.
I do not think there is very high risk as long as pH is not 1 or lower. But I will personally use PP if it´s possible. As polyolefin, there is nothing that dilute nitric or any other chemical involved could do to it, even when hot. You can many times see that something is going on with PET, because as it start to disintegrate and react, it often develop little cracks and turns little translucent.

Maybe setup small test run with other PET container in some small beaker and observe it for some time - if it is like it should be or not.


----------



## Gsracer

Hmmm, thank you for that Orvi. I will stick with PP. I went out today and found a thicker container and some PP egg crate type material.

The plan is to use the PP container, line it with muslin cloth and place the egg crate mesh which has a thickness of about 1/2 of an inch inside. On top of this i will place my 1 kg anode bars.

The though behind this is the slimes tend to compact previously before the run was over and lower current flow. Causing me to have to change out the liner cloth liner and more work. What i want is for the anodes to be above the muslin so that the anode is never actually resting on the bag compacting. The idea is that the slimes will just fall off the the anode and not be compacted by the weight of the anode itself. This will also help me with keeping the anodes cleaner for restarting the cell as before i would have to scrub them into a beaker wait for the slimes to settle, dry them etc etc.


----------



## orvi

Gsracer said:


> Hmmm, thank you for that Orvi. I will stick with PP. I went out today and found a thicker container and some PP egg crate type material.
> 
> The plan is to use the PP container, line it with muslin cloth and place the egg crate mesh which has a thickness of about 1/2 of an inch inside. On top of this i will place my 1 kg anode bars.
> 
> The though behind this is the slimes tend to compact previously before the run was over and lower current flow. Causing me to have to change out the liner cloth liner and more work. What i want is for the anodes to be above the muslin so that the anode is never actually resting on the bag compacting. The idea is that the slimes will just fall off the the anode and not be compacted by the weight of the anode itself. This will also help me with keeping the anodes cleaner for restarting the cell as before i would have to scrub them into a beaker wait for the slimes to settle, dry them etc etc.


Good idea, I also think about same thing - somewhat hang them or suspend them on something. 
Yes, slimes thicken with time as more of them accumulate. And as they are created in same little area (silver going down steadily), they thicken and slow th flow of the ions down.


----------



## kurtak

Gsracer said:


> After searching through threads and design ideas i found one that peaked my interest and decided to build it.
> 
> *If he sees it he will know its his*
> 
> 
> 
> Pics
> 
> View attachment 48253
> 
> 
> 
> View attachment 48254


Just saw this

Per the bold print --- all I can say is - *COPY CAT !!! --- LOL !!!*

Kurt


----------



## Gsracer

I say this sir 'Imitation is the sincerest form of flattery". 

It was a great idea.


----------



## Gsracer

Getting closer to starting up the new cell.

I got my anode basket, and platfrom for the anodes. Just have to put them together. Make some electrolyte and im off to the races. Hope to get it all together on tuesday. Ive had to slow down a little bit as me and the Mrs just had a baby 2 weeks ago. So im finding time here and there

As for today, i poured 5.5 kilos of anode bars. I was running out of jars to keep my cement silver, still have about another 5 kilos left to pour.

The black spots are a little bit of graphite from the crucible, i think its time for a new one for my cement silver pours.


----------



## kurtak

Gsracer said:


> The black spots are a little bit of graphite from the crucible,* i think its time for a new one* for my cement silver pours.


Per the bold print - get yourself a cast iron mold like this one - it's what I use for pouring my one kilo anodes for my cell (which just like your new cell build)

3 one kilo anodes (poured in that mold) fit perfect in that cell

I got mine from Romanoff for around $20 - $25 (many years ago)

I will post more about actual size when I get more time









40 oz Cast Iron Loaf Bar Ingot Mold W/ Handle Melting Gold Silver Copper Scrap | eBay


New Cast Iron 40 Troy Ounce Loaf Ingot Mold for Casting Gold, Copper, Silver, Aluminum. Designed with Slight Taper for easy Ingot Removal. Holds up to 40 Troy Ounces of Gold! PMC Supplies LLC.



www.ebay.com





Kurt


----------



## Gsracer

Thanks Kurt, its actually not the mold, more over the crucible, ive used it for probably 50 pours. I think its the left over nitric that oxidizes it. No matter how well rinsed and dried my cement is, i always get a bit of brown smoke when i put the cement powder in it. The graphite from the crucible tends to come over with the pour. I just remove it with some dilute sulfuric.

Made some more progress on the cell today, just have to clean up some rough edges. Looks like i will be able to put it in service tommorow. Going to go with a final concentration for electrolyte of 550 grams of silver in 4 liters. I think that will be a good starting point. 

So i made an anode basket, with a strainer to keep the anode off of the muslin directly. Should help with the slimes not compacting.

I made it out of a PP floor tile.




This will sit in the anode basket on top of the muslin and the anode will sit on top of it.




Plenty of area underneath for the current to flow.




Here it is mocked up. The anode itself will be exactly 4.5 inches away from the cathode.


----------



## Gwar

Quick question, I noticed on your power supply it is at 3.49 V 3.38 Amps and 11.79 Watts, my first try with a silver cell never produced watts on the indicator, was I doing something wrong ?


----------



## Martijn

P = U × I 》》3.49 x 3.38= 11.79
So whenever there is a current flowing (and thus a voltage over a load), there will be power consumption in watts. 
Did you have that function turned off maybe?


----------



## Gwar

I don't believe so, rather than hijack Gsracer's thread I will start a new one..


----------



## Martijn

Ah. I see. 3.57 Volts times 0.018 Amps equals 0.063 watts. Your lcd display can show no smaller than 0.1 watts. 
So your power consumption was not big enough to show on the meter. 
No problem. 
Watch and set the current to the desired value. Voltage and watts will follow.


----------



## Gwar

Many thanks Martjin !


----------



## Gsracer

GWAR, i believe there is something wrong with your setup. There is no way at that distance your only getting such low amps. Based on my experience you should be getting well over 4 amps at that spacing and short out the cell in minutes.

What are you using for filter cloth.


----------



## Gwar

Gsracer, That was an illustration of my first attempt, the second try I was at 1.9-2.5 Amps and with a different set up, however I still wasn't drawing any wattage..


----------



## Gsracer

why dont you switch to a SS cathode? Ive never tried graphite, but it doesnt seem as efficient.


----------



## Gsracer

So got the new cell working today, so far it is meeting my expectations as far as what looks like current capacity.

Final volume ended up at 3.8 Liters with 550 grams of silver crystals.

550 grams in 1 liter, beautiful.






Once i pushed the power button it started at 3.67 V at 5.35 Amps






After one hour the voltage settled at 3.57 V and 6.40 amps, not bad to start.





Looks like my basket design is working. The slimes are falling down off the anode to the bottom of the basket.


----------



## Gwar

Great design !


----------



## Gsracer

Thank you GWAR.



kurtak said:


> To put it all in perspective - here is a pic of my silver cell - it holds 4 liters electrolyte - distance between anodes & cathode is 4 inches & my power supply is 10 volt 10 amp output - my anodes are 4.25 inches x 1.5 inches - I can put 3 anodes in the anode basket so about a total of about 19 square inches of anode
> 
> When I first turn it on the amps start out at about 5 amps - that is a current density of about .26 amps per square inch --- at the end of the run when the crystals are closer to the anodes it will be pulling 9.5 amps if not the full 10 amps which means the current density has gone up to .5 - .52 amps per square inch --- with only 19 square inch of anode



@kurtak 

Kurt hoping you can give me some insight.

Cells been running for about 6 hours. Electric is holding steading at 3.5V with 6.60 AMPs. Should be close to 150 grams deposited so far, which is what i would previously do in a whole 24 hours. However...

Im starting to get an accelerated growth and the cell is heating up. It is sitting at 110 degrees F. I've noticed in the past when the cell heats up I've had a similar issue with growth too fast. I'm wondering if i do not have enough anode area causing too high of resistance. Or if its something else im missing entirely.

I didnt see you mention concentration of electrolyte

Specs of the cell. 
Im at 550g in 3.8 L
Anode to cathode distance 4.5 inches exactly
Cathode area 9"x5.25 = 47.25 sqin
Anode area 1 kilo bar measuring 4.05" x 2.33" = 9.436 sqin. about 1/8 submerged so if you add that area as well we are at 11.01 Sq in

Current pic below

I dropped the voltage down to 3.00 V which is running at 5.5 amps to see if that helps drop the temp a little bit.


----------



## Martijn

Limit the current to a maximum, not the voltage!.

The closer the silver grows to the anode, the lower the resistance is between the anode and the silver on the cathode, lower resistance means bigger current.
more current means more power consumption>> more heat.

Set your current to the desired Amps corresponding to the surface of you smallest surface, be it anode or cathode surface.
if the resistance lowers, the voltage will drop because the current is limited.

How to do this: apply sufficient voltage and turn the current knob down. You will see the voltage adjust automatically.
A good indication I use with all electrolytical cells: no bubbles forming>> no excess current. No depletion zones around anode or cathode.

Martijn.


----------



## Gsracer

Makes sense. Thank you Martin. 

What should my maximum amperage be? My smallest surface is the anode of course. 

What is the formula I should be applying for current density at the anode? Or is it just trial and error on each particular setup.


----------



## Gsracer

Overnight, I lowered the voltage to 1.12 to give me 2 amps, the solution cooled to ambient and crystal growth was much more in line with what i expect to see. Regarding the current density.

Found an old thread from GSP on the subject, mentioning specifically the heating issue...



goldsilverpro said:


> Sorry, but I can't think in centimeters. The anode is about 5 sq.in. on the one face that is facing the cathode. In the Thum cell, the most current used is about .35 amps per sq.in. (50 A/sq.ft.) of anode area. For 5 sq.in., this would be about a max of about 1.75 amps. If you go much higher that this, it will take more voltage. A voltage of 4 should be OK, but I wouldn't go much higher. It sounds like the anode size might be the biggest part of your problem. If you do increase the anode size, don't exceed the surface area of your cathode.
> 
> If the tank is round with a 10 cm diameter, it contains about .25 gallons. If it is square, it holds about .3 gallons. A Thum cell runs about 6 to 7 amps per gallon. Therefore, at the top end, you shouldn't run more than about 2 amps. If you exceed this, the solution will probably get too hot and this could cause problems.



So using GSPs numbers my anode 9.436 sqin x .35 amps/sqin = max amps of 3.30 Amps

Ill try this setting out today and report back.

Starting to sound like i need bigger anodes.....


----------



## Martijn

I think the advised current is now 25Amp / square feet, but that could be for one side of the cathode plate. 
I just setup a cell and test at which current there are no more bubbles forming by turning it down. 
Thats your highest desirable amp setting. 

Then its a game of try and see what happens. Slow crystal growth at low amps, thin long hairs at high amps. 
It all depends on what you want. 
Play around with the current.


----------



## Gsracer

So just to update.

Today I poured a new anode, i upped the area from 9.436 sq in to 12.386 sq in (the biggest mold i had) so i added 30 percent area.

I have experimented with the amperage with the power supply set to limit current.

If i don't set limiting, i can hit 6.72a at 3.51v. However the crystal growth is way too fast with long, spindly crystals. It would short out in no time.

All in all this cell appears to be working twice as fast as my previous one which would max out around 1.4 amps consistently to get nice crystal. Im a little disappointed that i cant turn up the voltage and utilize the amperage available. Open to suggestions...

Pics 





I think i found the sweet spot, with current limiting to 3.00 amps at 1.57 Volts. The crystal growth speed is manageable, every once in a while there is an offshoot that i have to knock down but it appears to be making denser crystal. Current density at the anode is .24a per sq in and at the cathode im sure its low.





Growth so far after 32 hours, should be somewhere around 384 grams




At this amperage the cell temperature doesnt go over 95 degrees.


----------



## Martijn

Sounds like you found your cell's sweet spot. To find out what the limit of your power supply is, set the course and fine knobs to maximum and read the voltage with open terminals.
Short the outputs plus and minus with one lead to see how far you can turn up the current. What are the specs? 30 volts at 10 Amps?


----------



## silver1

What you are experiencing is what sent me down the rabbit hole of rotating cathode design.
This was my first prototype. I built a large production model with a wiper blade that i sold to a client. If i can find the old pictures i will post them.


----------



## Gsracer

Martijn said:


> Sounds like you found your cell's sweet spot. To find out what the limit of your power supply is, set the course and fine knobs to maximum and read the voltage with open terminals.
> Short the outputs plus and minus with one lead to see how far you can turn up the current. What are the specs? 30 volts at 10 Amps?



Martin. Yea it seems like it. The power supply is 30v10a. When I say the previous design which was much smaller by comparison would max out at 1.4amps. I meant it in the sense, all I could run was 1.4a to get dense crystal growth. One thing to note. When I went to bed last night I was thinking back and reviewing previous pictures of the previous design. As It’s been over 6 months since I last ran it, Was that when the electrolyte concentration was fresh. Ie pure. I had a similar crystal growth speed and had to lower the amperage to around 1a till the copper concentration came up a bit. Maybe this will follow a similar trend. I’m probably around 2-4g/l copper by now. Let’s see how it goes when it gets to 10g/l of copper. I know many professionals start out by adding copper. So I guess I’ll see. 



silver1 said:


> What you are experiencing is what sent me down the rabbit hole of rotating cathode design.
> This was my first prototype. I built a large production model with a wiper blade that i sold to a client. If i can find the old pictures i will post them.




Wow. That is cool. I’m wondering if I could incorporate something similar. Would definitely cut down on the constant checking. Maybe not a rotating cathode but some sort of windshield wiper design I can make with a glass rod or the like to go back and forth inside the tank every so often. Should be pretty simple with a bit of tech. I’m a software engineer by trade so that’s more my realm. Thank you. Rabbit hole indeed. Lol.


----------



## Gsracer

Just wanted to share, cell has been running for 75 hours. It has digested a little over a kilo of anodes already. Once the copper concentration raised a bit. I was able to get some additions amps into it. I still have to monitor from time to time to make sure it doesn’t short. But it holds steady between 3-4 amps at 1.5-1-2 volts If I turn off constant current and set the voltage to 3.5 volts I get a little over 7 amps. But the cell gets hot and the crystal grows crazy fast. You can watch it.

Copper concentration is right around 5-7 gram / liter. 

Crystal growth is pretty dense. So that’s good.

Here’s some pics.






Here is a cool time lapse video with the cell turned up to 7 amps for around 3.5 minutes of time in 38 seconds.

View attachment IMG_7203.MOV


----------



## Martijn

Thats very cool to watch it collapse and grow back


----------



## Gwar

Great technique !


----------



## Gsracer

103 hrs. So far so good. Averaging a little over 3 amps per hour. I turn it down to 2 at night and try to run it close to 4 during the day.

One thing I’ve noticed is the large kilo anodes dissolve from the outside to the middle.

The amperage is steady so it seems the elevated basket design is keeping the slimes at bay.

I can pull the anodes out and they are relatively clean with no slimes sticking to them. 

The just fall down into the space between the muslin cloth and the plastic spacer.


----------



## Gsracer

So i decided to do a harvest today. I was having to go out every hour and knock the crystals down and i didnt want to risk a short through the anode bag at this point.








A small part of the appeal of this setup was i wanted to be able to harvest the crystal without having to breakdown the cell like i would have to do with my beaker setup.

In comes my custom made spoon. Drilled some holes and heated it till it bent so it would fit inside the cell and i could scoop the crystal out.





I was running out of time and had a family engagement so i left them sitting under some distilled water till i can rinse them better and dry them out. Also going to pick up a 3L beaker tomorrow so it will be a little easier. I would guess theres a little over a kilo and a half of crystal in here. But once i complete the run and teardown the cell i will post yeilds.





The whole time i harvested the cell was running, I topped it off with 250ml of electrolyte with another 100 grams of silver crystal dissolved to take account for any depletion. Copper concentration is now around 10 grams per liter. My guess is it will run another 5 or 6 days before the anode bag stuffs up. I should be able to get around 3kilos between breaking down the cell around every 10-12 days. My previous setup would only be able to produce between 1.3-1.5 kilos during the same time period.


----------



## kurtak

Gsracer

Have been following you progress - awesome - sorry I have not commented much (busy with other things) 

However I would like to make one comment

I see you are using glass rods to hold up your anode basket --- glass has a tendency to break

I use SS rods to hold my anode basket up - just saying - I would hate to see those rods break - like when harvesting crystals from the cell - as accidence do happen 

Kurt


----------



## Gsracer

Hey Kurt. Thank you. 

Your absolutely right. When I did it originally I only accounted for a 1kilo anode. With that size it didn’t seem like much weight for the 8mm rods. However as I had to change the anode size mid way. They are now closer to 1.3 kilo size. Additionally I didn’t take into account stacking another one on top when the first one starts to dissolve as I did as well. 

It’s a bit much for the glass. When I break it down I will swap out to some 1/4 stainless.


----------



## nwinther

What is your silver feedstock? Sterling tableware?


----------



## Gsracer

Yep. Almost exclusively. Also weighted stuff, plates and trays occasionally.


----------



## orvi

Excellent work. Very pleasant to watch your progress and results.

To the overheating issue, I just add one thing. Amperage = electrons make the silver crystals. Not the voltage. It is very easy to calculate the power consumption. Just multiply voltage with current - and you have the result. There is only certain voltage needed to free silver as silver cations, which will flow through the electrolyte and deposite on the cathode. All "excess voltage" will dissipate as heat.
We try to push the cell to the maximum working speed by forcing the voltage up, causing amps to also ramp up. This inevitably lead to the excessive power consumption, and you can clearly see it as rise in operation temperature of cell. It eventually stabilize at certain temperature - as heat is dissipated from the cell to the enviroment/room etc.

Because there is limited ammount of ions in solution, for shorter period of time we can see conductivity as constant. You can push more amps by ramping the voltage up, but this also cause unwanted overheating and also low current efficiency = bigger electricity bill 
As you figured out, simplest way how to get better current density and efficiency is to enlarge the surface area of the electrodes. Sreetips goes with shot - and this obviously help to increase surface area. You can go with casting "plate-like" electrodes. Just don´t fill the mold to the top. Cast for example two 0,5kg bars instead of one 1 kg bar. And then stack these thinner plates bit "diagonally" in the basket, leaving spaces in between them.

Another option would be to cool down the setup somehow. Mount small electric fan to the side of the setup, or put the whole container to the bigger vessel with water - to enlarge heat dissipation surface.


----------



## Gsracer

orvi said:


> Excellent work. Very pleasant to watch your progress and results.
> 
> To the overheating issue, I just add one thing. Amperage = electrons make the silver crystals. Not the voltage. It is very easy to calculate the power consumption. Just multiply voltage with current - and you have the result. There is only certain voltage needed to free silver as silver cations, which will flow through the electrolyte and deposite on the cathode. All "excess voltage" will dissipate as heat.
> We try to push the cell to the maximum working speed by forcing the voltage up, causing amps to also ramp up. This inevitably lead to the excessive power consumption, and you can clearly see it as rise in operation temperature of cell. It eventually stabilize at certain temperature - as heat is dissipated from the cell to the enviroment/room etc.
> 
> Because there is limited ammount of ions in solution, for shorter period of time we can see conductivity as constant. You can push more amps by ramping the voltage up, but this also cause unwanted overheating and also low current efficiency = bigger electricity bill
> As you figured out, simplest way how to get better current density and efficiency is to enlarge the surface area of the electrodes. Sreetips goes with shot - and this obviously help to increase surface area. You can go with casting "plate-like" electrodes. Just don´t fill the mold to the top. Cast for example two 0,5kg bars instead of one 1 kg bar. And then stack these thinner plates bit "diagonally" in the basket, leaving spaces in between them.
> 
> Another option would be to cool down the setup somehow. Mount small electric fan to the side of the setup, or put the whole container to the bigger vessel with water - to enlarge heat dissipation surface.




Thanks Orvi, the casting .5kg bars is a good idea, i must confess i hadnt even thought about it. But it would definitely work really well in my setup.

Its funny that you mention the cooling setup, i was thinking of that very thing this weekend. Get a larger container and fill it with water to act as a heat sink.

This opens up interesting ideas and experiments. We know that increasing the temperature creates quick growth just not dense. I was thinking what would happen if you lower the temperature, to say 60 , 50, or 40, maybe 30 degrees. Wouldnt be that difficult with a small freezer, small radiator and a pump. Maybe you would get denser crystal or larger crystal. Im really wondering here, what do you think?


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## orvi

I do not have experience with lowering the temperature unfortunately. One factor is certainly viscosity of the electrolyte, which will go up as it will cool down. Sometimes, specialty polymers or oligomeric additives are used when creating dense, even copper deposits instead of crumbly texture of dendrites. It could help, but in electrochemistry... You cannot be certain with theory without testing it out in real life 

If you get some bigger vessel with water, put the cell into it, and you will run fan over the water surface, it will cool the system more efficiently, as the water evaporation helps a lot. Importantly, cover the top of the cell to prevent unwanted evaporation of electrolyte with some plastic wrap or something. To prevent crystal growth on the edges of bowl and such.


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## Gsracer

Just wanted to update.

The cell has run for 18 days straight. I’ve harvested 3 times without breaking the cell down. About every 5 days.

So far including what’s in there now I have refined a little over 5 kilos. It’s running pretty well. As the copper concentration increased I got nicer crystals. I’ve learned what it likes as far as amperage goes.

The anode filter is already getting a little full of slimes. So I think I’m going to let it run till Sunday and then brake it down. And I’ll get full numbers of how well it produced.

Copper concentration is sitting at about 25 grams per liter. I have been adding to the electrolyte which started at 550 grams of silver in 4 liters and is sitting at 800 grams now.

I probably could get another 2 kilos through it. But Since im going to break it down this weekend I’m just going to swap the electrolyte and reset just to be safe.

Heres some pics.


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## Gsracer

Ok everyone so its official i have shut down cell version 3.0. Not because of any issues more so because i ran out of feed stock.

It has functioned pretty flawlessly. 

Some fun number. 

The cell ran for 46 days or 1107 hrs. 24 hrs a day. 

It averaged 13.06 grams per hour or 10.08 troy ounces per day ( double my previous capacity)

In total it produced 14,465 grams of crystal during this time.

This was divided into 2 runs, I broke the cell down around day 28 to change the anode filter material and modify my little basket. After the modification it functioned a little better and i was able to get some more amps into it. The electrolyte was also changed at this time. I was able to harvest during this time as i have shown between breaking the cell down. Every harvest was around 1.3-1.6 kilos of crystal with the last run being over 2 kilos because i let it run to conclusion.

I would start with 600 grams of crystal in 4 liters and ended up at around 900 grams in the electrolyte at the first change. The second shorter run started with 500 grams and 750 at conclusion. 

During this i monitored copper concentration via standard dilutions of copper nitrate and given what i was observing versus cement silver recovered from the electrolyte my feed stock was around 98.2% pure which was inline with what i was seeing in the electrolyte.

I reached my stacking goal at 100 lbs of silver. Im actually at 101.4 lbs of the shiny stuff.

At this point I'm unsure where to go, i may start working on gold. I have never worked with gold. I have gotten pretty good at silver at this point.

I really want to take a second to thank everyone who has chimed in and helped me along the way!

Heres some pics for those that are interested.

Day 46 Break down






Modified filter basket, keeps the anode bars out of the slimes, makes things ten times cleaner




Shot of the crystal in the cell and after draining.













Rinsing and cleaning









Final weight of that run 2238.8 grams 7 days worth of growth.







And just for fun all of my refined silver, some i have poured into kilo bars, and some smaller bars. It saves room


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## snoman701

Very nice!


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## Gwar

Impressive !


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