Silver Cell Filter Bag Slimes

[kadriver]

I have harvested about 15 troy ounces from my electrolytic silver cell.

I have cleaned the filter bag three times, saving all the black powder and other material from each filter carefully washing into a large glass container.

I have it settling in the glass container and will siphon off the liquid once settling is complete.

How should this material be handled?

I understand that there may be some platinum and other metals in with this material.

I am reading Hoke on the platinum group metals and how they should be delt with.

This will be my first attemp at recovering any platinum - if there is any to recover.

I have included a photo of the powder.

My first thought is to dissolve any base metals and silver in a small amount of dilute nitric acid. This should leave any gold or platinum solids behind.

After that, I am clueless on what to do.

Any guidance would be greatly appreciated

kadriver

 

[lazersteve]

The slimes can be treated with AR.

Steve

 

[Harold_V]

The slimes can be treated with AR.

Steve

While that's true, unless there's a substantial amount of palladium present, I don't think I'd make that suggestion. What I would suggest is a digest in dilute nitric first. That will eliminate the predominance of residual metals, leaving behind only gold and platinum (with an outside chance of traces of rhodium and iridium).

It most likely will result in the digestion of almost all of the slimes unless there has been dental gold processed.

Harold

 

[metatp]

I have my slime from the silver cell, but I assume there is no gold, since the anodes were from cemented silver from contact and jewelry dissolved in nitric acid. I did get a very small amount of gold left over after filtering the silver nitrate. Even though I have a small amount of slime, should I assume that it is most likely Pd and Pt?

 

[Harold_V]

I have my slime from the silver cell, but I assume there is no gold, since the anodes were from cemented silver from contact and jewelry dissolved in nitric acid. I did get a very small amount of gold left over after filtering the silver nitrate. Even though I have a small amount of slime, should I assume that it is most likely Pd and Pt?

I'm not convinced you can eliminate anything. When you inquart, if you mess up, or if you crush the digested gold prior to dissolution, minute particles, even colloidal, are put in suspension. Unless you've processed some dental gold, the chance you'd have platinum isn't good, although not impossible. If you had palladium present, you'd have taken note by the color of your solutions (in the initial digest) in that it colors solutions green, but if there's a substantial amount present it can be brown.

What I expect you'll find is just gold---but be prepared for anything. Give the slimes a wash in dilute nitric (use very little--just a few drops) and see what happens. If you have any palladium present, you'll know by the color of the solution. If it remains blue/green, add drops of nitric until you get no further action on the slimes. Decant the solution (silver nitrate) then rinse the slimes well, then digest with a few drops of AR. When you have everything in solution, you can test to see if you have any platinum metals present by placing a drop of the solution in a spot plate cavity, then adding a crystal of ferrous sulfate. That should precipitate gold, leaving behind a solution that may or may not contain platinum metals. If the solution remains a yellow color, test with stannous chloride. If you get a reaction, you may wish to repeat the same test, but instead of testing with stannous chloride after precipitating the gold, test with DMG to see if you have palladium present. You should be able to pinpoint exactly what you have by following these simple instructions.

Harold

 

[nickvc]

I wouldn't hold your breath that your slimes contain much platinum given the source of materials processed. The slimes may contain some gold and perhaps some rhodium from the plated jewellery but I think the vast majority will be base metals. My advice is to keep the slimes until you have reasonable quantities and then follow Harold,s advice and wash it in dilute nitric and see what's left.

 

[kadriver]

Thanks so much. I will do a small test as Harold recommended to see what happens. Then I will just keep the slimes until I have enough to process.

I thought for sure there would be at least some platinum since silver is a carrier of this metal.

Also, I have had to double bag using the filter material that I am using. It is a tightly woven synthetic, but if a single thread gets disturbed it creates a place for the slimes to get throught to the crystals.

Can someone recommend a good source for the proper cloth to use for the filter bags? I am having too much trouble with the material I am using.

kadriver

 

[4metals]

I have had great success with 13 oz polynap bags from http://www.anodeproducts.com

All the bags are custom and they are relatively inexpensive, for example, 1" x 3" x 20" heavy duty bags for individual anodes were $2.95 each in 2009.

I'm not sure they will deal with individuals but if you pre pay and ask nice they may. They are a reputable company and have been around for a while.

 

[kadriver]

4metals, thank you for the suggestion. I will check it out.

 

[metatp]

4metals, thank you for the suggestion. I will check it out.

kadriver,
If you would, please let me know what you find out. I just made ~9 ozt in my silver cell, and am not sure if the current material I am using will work very well the second time around.

Thanks,
Tom

 

[metatp]

What I expect you'll find is just gold-

Experience is usually right. After a nitric wash and then digestion in AR, the solution tested positive for gold. I haven't tested for Pt yet. Solution did not appear to be green, so probably no Pd. I am very surprised that there was gold (though not much from my 9 ozt batch).