First attempt at silver refining

[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]

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]

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]

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]

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]

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.