Non-Chemical Silver Cell details

[Junkman Jim]

Here are some pictures of my silver cell. I constructed it with a container I bought at Walmart, the container is 7"x7"x7". I drilled holes to accept stainless steel rods to suspend the polyester canvas bag, cathode, and anode. The spacing between the cathode and anode is about 3".
The electrolyte is 68% nitric acid saturated with 20 or so ounces of silver. I'm using 1.25 volts measured at the cathode and anode bars. The source is 3 10 to 12 ounce bars of silver and that is plated onto 3 strips of stainless steel 1" x 4", .030" thick. The attached cell pictures are after about 6 hours of plating, the long crystals grow after about 10 hours or so. (see additional pics.)

 

[Noxx]

Very nice ! I love the crystals shape.

 

[Anonymous]

how many amps is you cell running? Nice by the way. Were did you get a power supply at that voltage? Sorry for asking so much but I can see were your dissign could be useful to me.

Jim

 

[Junkman Jim]

I'm not sure how much current the cell takes. The supply is capable of about 80 amps at 0 to 5 volts. I built the supply myself to include the transformer.
I started with a transformer capable of a couple hundred watts, I removed the secondary and replaced it with 8 turns of No. 8 insulated wire with a center tap. I put a 2.5 amp variable tranaformer on the input of the stepdown transformer.
One day when I find some spare time I'm going to hook up an ammeter as I'm also curious how much current this thing draws. The supply doesn't even get warm , I'm guessing it only draws around 10 amps.

 

[Anonymous]

Looks real nice, did you build the diode bridge also? I have diodes from microwaves and think they should be ok.

The transformers I have are 2000 watts so I know that I can get the power, I was also thinking of several taps for different voltages. I have already taken the old secondary out because I made a small spot welder with it.

Jim

 

[Shecker]

A very nice little system. If you were using impure silver Dore that contain gold, pgm as your starting put, the precious metals other than silver would remain behind in the bag. Only palladium, if present, would build up in the electrolyte.

Randy in Gunnison

 

[goldsilverpro]

Very nice, Jim. About 1 gallon. Twenty oz of Ag/gal. Seems like the parameters you've chosen have solved the problem of producing large crystals. How large is the crystal in the 2nd photo?

How did the Copper get into the cell? Did you add it intentionally or did you use sterling as a source of silver? If you added it intentionally, how much did you add?

You can get a close approximation of the amperage by weighing the silver output over a period of time. One amp for one hour (an amp-hour) will produce about 4.02 grams of silver, at 100% cathode efficiency. The actual efficiency should be about 96-99%.

 

[Anonymous]

GSP, is it amperage only that matters when comparing the amount of silver deposited or will higher voltage have an effect?

 

[Junkman Jim]

Looks real nice, did you build the diode bridge also? I have diodes from microwaves and think they should be ok.

The transformers I have are 2000 watts so I know that I can get the power, I was also thinking of several taps for different voltages. I have already taken the old secondary out because I made a small spot welder with it.

Jim

The power supply is full wave, one 40 amp diode on either side of the center tap. You can see the studs of the diodes sticking out the back of the supply (lower left of picture). Generally the larger the tramsformer the fewer volts per turn. You may only need a couple turns to get the necessary voltage. I thought about taps but a variable transformer is so much more convenient, this supply goes from zero to five volts. I can do copper at .3 volts, silver at 1.25, or silver strip at 4 volts. Alternator diodes should work fine.

 

[Junkman Jim]

Very nice, Jim. About 1 gallon. Twenty oz of Ag/gal. Seems like the parameters you've chosen have solved the problem of producing large crystals. How large is the crystal in the 2nd photo?

How did the Copper get into the cell? Did you add it intentionally or did you use sterling as a source of silver? If you added it intentionally, how much did you add?

You can get a close approximation of the amperage by weighing the silver output over a period of time. One amp for one hour (an amp-hour) will produce about 4.02 grams of silver, at 100% cathode efficiency. The actual efficiency should be about 96-99%.

The large crystal is just over an inch.
I used silver salvaged from tanalum capacitors for my electrolyte, the green color of the electrolyte is probably iron as there was a steel washer in each capacitor. The electrolyte also contains some tin, lead, and a little bit of copper. The electrolyte in the cell in the picture has produced 120 troy ounces of silver.

 

[Junkman Jim]

GSP, is it amperage only that matters when comparing the amount of silver deposited or will higher voltage have an effect?

If you increase the voltage other metals will plate and contaminate your silver

 

[goldsilverpro]

Are you talking about the electrolytic tantalum/silver capacitors with the red or green plastic plug on one end? If I remember right, the red ones ran 40% silver and the green ones ran 25%.

Do you have proof that increased voltage affects the purity? If so, how did you determine that? The standard cell runs at 3V and produces 999.9 silver. The anode current density is about 50 amps/sq.ft. Only certain specific impurities, such as Pd or Cd, cause problems. Of course, large quantities of any metal will cause purity problems. The limit on copper is about 12 oz.gal. Of course, the main purpose of a standard cell is to produce pure silver and not to produce pretty crystals.

Do you know the total running time to produce the 120 oz?

 

[Junkman Jim]

Are you talking about the electrolytic tantalum/silver capacitors with the red or green plastic plug on one end? If I remember right, the red ones ran 40% silver and the green ones ran 25%.

Do you have proof that increased voltage affects the purity? If so, how did you determine that? The standard cell runs at 3V and produces 999.9 silver. The anode current density is about 50 amps/sq.ft. Only certain specific impurities, such as Pd or Cd, cause problems. Of course, large quantities of any metal will cause purity problems. The limit on copper is about 12 oz.gal. Of course, the main purpose of a standard cell is to produce pure silver and not to produce pretty crystals.

Do you know the total running time to produce the 120 oz?

GSP,
These capacitors are 3/8" in diameter and about 3/4" long and have a slug of solid tantalum immersed in potassium hydroxide. There's a steel washer with a green or red glass insert surrounding the kovar lead that connects to the tantalum slug. The washer is soldered to the case which is almost pure solid silver. It only takes 15 or 16 cases to make a Troy ounce of silver.

I was told by a 74 year old friend who's lifetime livelyhood has been recovering precious metals that increased voltage will plate other metals which seems reasonable since different metals require different voltages.
Oh, by the way try to find those voltages on the web or even in Hoke's book. Since you mentioned it, I might try the higher voltage although I'm getting tremendous results at 1.25 volts.

I haven't kept track of the precise time but the cell produces 6 to 12 Troy ounces in a 24 hour period.

One problem I have is connectivity, I drill my silver bars then screw a stainless steel hook into them and hang them on a stainless steel bar. I need a better way of making that connection, I've tryed other metals, you just can't keep the corrosion away.

 

[scrapman1077]

could you post a pic of the capacitors? Thanks

 

[Anonymous]

If you bent your anode hooks a little different you could use split bolts to
hold them down and get better conductivity. Also, maybe a conductive grease.

or instead of round bars use square and hold with clamps for better conductivity.

 

[Anonymous]

So the large transformer is stepping down the smaller variable transformer or are you using the output from the variable transformer to choke the larger one?

 

[Junkman Jim]

could you post a pic of the capacitors? Thanks

Scrapman,
Here's a couple pics of the solid tantalum caps to look for, the two on the left have solid silver cases (worth more than a buck apiece), the next one is silver plated brass (worth much less), the two on the right are solder plated brass (only worth the value of the tantalum), and the case on the one in front is solid tantalum.
I tryed to find the price of scrap tantalum, as near as I can tell it'a somewhere around $45.00 per pound.

 

[Junkman Jim]

So the large transformer is stepping down the smaller variable transformer or are you using the output from the variable transformer to choke the larger one?

Jim,
Put the variable transformer on the primary of the step down transformer.
If the step down transformer is capable of 200 watts output that means the input is 200 watts. If you want 0 to 5 volts wind the secondary for 5 volts, the variable transformer will then take the input of the step down from 0 to 120 volts taking the secondary from 0 to 5 volts. 200 watts at 5 volts is 40 amps. Be sure the wire you use is capable of 40 amps, I used two windings of No. 8 copper.
Hope this helps.
Thanks for the ideas on the anode hooks,
Jim

 

[goldsilverpro]

Try this. Grind the hooks so they form a knife edge where they make contact to the bar.

 

[Anonymous]

GSP I think that is an excellent idea.