Silver Electrolytic Cell Volume

[4metals]

I have a client who has a cell which has been producing for a year now but he spaced the basket (it's a Thum cell) too far from the cathode (6") and when I was in to see him, coincidentally on a day when he had the cell broken down to change the electrolyte, I pointed out the problem. He has since made the distance 4" and the cell draws less volts but the silver grows faster and more spindly and needed more attendance.

Tartaric acid additions, small just a few grams, made the crystals denser and bought him more time between scrapings. The crystals were more stout as well, much more dense.

 

[shyknee]

hi 4 metals did they look like this? i am just wondering if they where thicker

 

[stihl88]

Can someone explain as to why the Silver crystals don't re-dissolve back in to the solution once they have been electrically precipitated as crystals.
Is it that all of the HNO3 is expected to have been used up in the initial manufacture of the AgNO3 electrolyte? If so i would imagine it would be fairly crucial to get the initial HNO3/H20 to silver ratio fairly correct when making the AgNO3 electrolyte to prevent the repetitive dissolution of the crystals upon their development.

Sorry for the what is likely a simple Question, but I'm quite interested in this Silver refining via crystal method and some simple things need clarifying for me sometimes.

Regards

Stihl

 

[kadriver]

I am just like Stihl - I was wondering the same thing. Those crystals are very thin and it seems that even a little nitric acid would dissolve them easily.

I would also like to know what is going on inside that cell. I can observe a flow of some sort of wavey pattern dropping down from the bottom of the basket, while I see occasional bubbles rising to the surface.

Can some one describe briefly what is happening inside the cell.

Shyknee, those crystals in the blue glove are unbelievable - how can I get mine to grow like that?

I have included a photo of the inside of the first filter bag I used. I was using cememnted silver bars for anodes - not much in the way of deposits from those bars.

I was going to dissolve a stering silver bowl and cememnt the silver when I realized that all I had to do was melt the bowl and pour a bar for an anode. Of course when i put this melted sterling bar in, the electrlyte began to turn blue green.

There is only about 4 inches from the top of the crystal growth to the bottom of the basket.

Since putting in the impure bar the filter bag has gotten much dirtier with black residue.

The power supply is set on six volts, but only about 4 volts on my meter. The amps are about 4.8 or so. The crystals look real good now and i am happy with the way it is running.

Soon I will have my first 999 pure silver bar.

Thanks - kadriver

 

[butcher]

Here is how I understand it?
The external DC current oxidizes the silver anode (with nitrate anion in its vicinity), it gives up its electron, and becomes a cat ion in the electrolyte (silver nitrate solution), this cat ion is in solution,

at the same time on the other side of the cell near the cathode, the silver nitrate electrolyte around the cathode (silver from solution) is reduced gaining an electron changing this back to the silver metal, this is formed from the electrolyte and not the same silver cat ion that left the anode, depending on conditions the silver electrolyte is a certain concentration of silver cat ions and nitrate anions (nitrate anion which migrate to anode to get another silver cat ion keeping same amount of silver to nitrate concentration to the solution), this will stay the same concentration no matter how much silver dissolves or plates out (temperature or PH may change things some) but silver to nitrate ratio basically stays the same (inert anodes can change this but that is a whole another story).

I am not that smart about this but I believe the original electrolyte mix will determine resistance of cell, PH, metal concentration and will have a big effect on how well or what form the crystals will plate out.

Reading through the forum you will find some much better discussion on silver cells.

 

[butcher]

From reading the silver cell text that Steve posted, I see the thum cell runs at a suggested 3.0 volts to 4.4 volts and a current of 0.35 to 0.4 amps per square inch of anode area

For discussion lets say 3 volts and 0,35 amps and using one square inch of silver anode area.
Since Ohms law says: volts divided by amps is equal to resistance.
Then 3 volts divided by 0.35 amps equals 8.57 ohms.
So in this cell the cells resistance is 8.5 Ohms. (Electrolyte and spacing may differ)
Since Ohms law also says: watts = volts x amps.
Then 3 volts x 0.35 amps = 1.05 watts
So the cell is using about one watt (heat work) (again in this perfect cell).

Say I only have a 6-volt power supply (DC battery charger), and want to run my cell on 3 volts.
Two resistors in series, if both are the same size the voltage divides, but the current stays the same through both resistors,
so if I put two resistors, or light bulbs, or silver cells in series the voltage they receive will be half each of the supply, example two silver cells of the above resistance in series on a 6 volt supply battery would get 3 volts each, and if both cell ran at same resistance (unlikely ) the total circuit current would be 0.35 amps, and 2 watts of power used up as heat, problem here the cells resistance is variable, this may work but I want a better way and do not want to maintain two cells,

I could get a resistor from radio shack large ceramic type in a 10 ohm (close to 8.5 ohm of my cell) 10 watts so it can dissipate the heat, and wire it into series with my cell (insert it in to wire going to anode) (plus of voltage supply battery charger to one wire of resistor and jumper from other wire of resistor to my anode silver bar in the cell, now my total circuit will have 18.57 ohms and 0.32 amps, the resistor would get just a little more than three volts my cell just a little less than three volts from my six volt supply, and since the battery charger will actually put out a little more than six volts (about 7.25 volt to charge battery) my cell would be within the 3 to 4.4 volt range,

Ok now but our cells resistance changes and Kadriver said he had read 4 amp draw on his running at 6 volts, this says to me his cell resistance was 1.5 ohms when he done his readings much less than our perfect thum cell here, this is getting close to being a short circuit, (maybe a silver needle fixxin to burn his cloth?), well if our cell shorted out we still have the 10 ohm resistor in circuit, so a most we have is 6V./ 10 ohm = 0.6 amp on resistor, and 0.6amp X 6 volt = 3.6 watts of heat on resistor, our 10 watt resistor can handle that worst case scenario.

But we can use a light bulb instead of a resistor, this will give us an indication of how are cell is running, will limit current from our charger, and divide the voltage from our power supply between the light bulb and the silver cell if we put it in series with the cell as we did the resistor, I would use a 12 volt tail lamp from a vehicle like the #1157 tail light bulb(auto parts or radio shack you can solder wires to it or just get a socket for it) about 2100 milliamp (at 12 volt its hot resistance is about 5.7 ohms, now running cooler on about 3 volts in this circuit that will differ). A shorted cell the lamp will limit current, indicate the short, protect your battery charger.

Again with the light bulb take the positive from your battery charger to one wire of bulb the other wire of bulb to anode silver bar in your cell.
(Different bulbs will give different values their filament resistance varies with type of bulb), you could do experiment with a six volt tail lamp, it would be hard for me to calculate the values as we are running bulbs @different voltages and filaments will heat different, and here your cells resistance is also a variable.

All I can say is Try it you may like it, (and thank OZ for the suggestion).

 

[stihl88]

Great posts Butcher,

Another option could be to wire in series a Variable Resistor of a high watt value along with an LED and a resettable fuse.
This would be a more sustainable setup with the option to change the voltage with the Variable resistor when or
if required.

I'll be building my own Cell setup over the Christmas break and i might try the setup Ive described here.
I'll be using a PC power supply and can tap into the 3v rail with 18 Amp supply. Now to find a Variable Resistor
than can handle 10 Watt :roll: (May as well leave the trimpot out if using only 3v rail anyway)

I would love to design a dedicated power supply circuit for Cell Refining and make one from scratch, Ive got all the software,
tools and experience but it's probably just as easy to buy a dedicated variable power supply.

 

[kadriver]

Butcher & Stihl:

Thanks you guys. I am not up on my electrical theory so I had to read what you wrote slowly, but I think I get it.

I have not had a chance to look at the site that Steve suggested yet, but I will.

I like the idea of having a cell rig with a light and circuit protection.

I actually had my cell crystals grow and come in contact with the basket. When I seen it (heard it first) I made a noise I had not heard myself make before.

I did an emergency shut down and thought that I had already ruined my new toy. But the material of that vacuum cleaner bag saved me.

That is why there is silver in the bag in the photo - I changed it out just to be safe - no burn through, and no contaminants got into the electrolyte.

I am really pleased with the performance of that bag material - but i don't know what it is.

I like the idea of having a light bulb as an indicator of short circuit. I assume the bulb would get dimmer as I got closer to a short circuit.

Butcher, thank you for the description of the cat ions and an ions being exchanged. The solution stays the same however. Who thought all this stuff up? My hat is off to them, whoever it was.

Thanks to all.

kadriver

 

[Barren Realms 007]

Possibly put a dimmer switch in the circuit.

 

[shyknee]

Shyknee, those crystals in the blue glove are unbelievable - how can I get mine to grow like that?

I used 2 silver cell setups connected in line with a 1.5v @ 300 milliamps plus it took more than 24 hours to grow from a 2" spacing of the anode to cathode ,and i used clean silver for the setup (my electrolyte looked like yours) and saturated the electrolyte with silver first .

 

[kadriver]

Thanks - am going to try it - those crystals of yours look really dense.

 

[stihl88]

Possibly put a dimmer switch in the circuit.

Good idea Barren i forgot about the old dimmers, they can handle the heat!
To try and source a normal trimpot that does the same thing as the dimmer
you are paying through the nose but a dimmer should be more than fine for
this application. I'll post some pics of my setup when i get around to building it.

Lazersteve> If i buy your silver CD can it be downloaded from a host site or do i have to have it mailed to me?

 

[lazersteve]

Lazersteve> If i buy your silver CD can it be downloaded from a host site or do i have to have it mailed to me?

It has to be mailed.

Steve

 

[azdave35]

i have a silly question that someone might be able to answer: i have a nitric solution that i have cemented all the silver out of...is there any way to cement or drop the copper and lead out of the solution?...i am trying to determine the assay of a silver ore...thanks in advance

 

[butcher]

when you cemented silver with copper you replaced the silver in solution with copper.
this worked because copper is higher in the electromotice or reactivity series.

you can do this with a metal higher than copper in the series, like Iron.

do some study on metal reactivity series Googling, it will open a new world for you.

 

[4metals]

Shyknee,

Those crystals are some of the most dense I've seen, the spindly ones in the beaker look more like what he was generating before tartaric acid. After the tartaric they were chunky like yours but not as large.

nice work.

 

[Oz]

Is there a simple way to convert potassium hydrogen tartrate (KC4H5O6) to tartaric acid (C4H6O6)?

As I am not a chemist, is it necessary to do so in this application? What if anything would the potassium (K) do in a silver/copper nitrate solution? Other typical contaminates?

Sorry for the curve ball.

 

[kadriver]

I had a problem with the silver cell.

The copper rod used to hang the basket partially dissolved.

Some of this material got in between the basket and the filter and ended up getting into the crystals. There was only a tiny bit, but I am concerned that this contamination has ruined this batch of crystals.

What is this material? Will it burn out when incinerated? Will my silver now be less than 999? Should I disassemble the cell and start over?

If I have to start over, then thats OK. This time I may use a thin pyrex glass rod instead of the copper rod for the cross member support - this will surely eliminate the contamination problem.

Also, the electrolyte is beginnig to turn green/blue. I have included a picture. Silver crystals were still forming.

So far I have gotten about 8 troy ounces of silver from the cell.

Any input would surely be welcomed.

Thanks - kadriver

 

[lazersteve]

I wouldn't worry too much about the copper unless it got in your pure crystals. If it did, then remelt them into a new anode and run it through the cell again.

You can use any type of rod you like for the support, even a wooden dowel, you'll have to clip the positive lead directly to the hanger hook though if you use a material that is not conductive. I use a large gauge solid copper wire for my rod, but it requires cleaning periodically due to the reaction with the nitrates in the cell.

Steve

 

[kadriver]

Thanks Steve.

What if I treated these contaminated crystals with hydrochloric acid to remove the copper, clean with much boiling water and melt? Could I then presume these crystals are still 999 in purity?

I will then filter the electrolyte, install a new non-reactive support rod and continue to grow crystals.

I think a glass rod support will be the least reactive of any material.

I hooked the lead directly to the hook welded onto the top bar, just like in the silver dvd.

When the time comes, I plan to cement the silver out of the electrolyte instead of going to silver chloride - does anyone see a problem with this?

Thanks - kadriver