First attempt at silver refining

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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!
 
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.

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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.


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Here is it all together.




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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.

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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.
 
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.
 
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.
Click to expand...
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.
 
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.1BC2B77D-91F2-4AAC-B599-183CA9FC1A35.jpeg
 
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.
Click to expand...
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

https://www.ebay.com/itm/380702042949?hash=item58a39c2b45:g:akMAAOSwfgpfjEHm
Kurt
 
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.

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

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Plenty of area underneath for the current to flow.

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


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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 ?
 

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

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


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

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

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

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