First attempt at silver refining

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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.

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The growth and power supply pictures

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


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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

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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.

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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.

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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.


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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
 
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!
 
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

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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

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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.

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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!
 
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.
 
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


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Running out of space


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

Here is what it looked like.

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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.

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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.


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

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