nickvc said:
Just a thought is it possible it's cadmium? I know spinning silver alloys use cadmium or used to.
I did have cadmium in some of the contacts I recovered silver from, but unless it was dragged down while cementing with copper, I don't know how it would get in the anodes, and stay in the slime.
I did also notice that this electrolyte was greener than others when it started to go foul. The anodes where fairly void of other PMs. There was very little slime. The anode were mostly made from silver from high temp silver epoxy. I wonder if it could be leftovers that didn't get incinerated.
It is like a golden orange color, and quite bright. If I get it again, I will take a picture.
I also just realized that I and now using silver plated copper wire that I melted to cement the silver. Maybe there are other metals in that wire.
I don't want to over think this, but here it what I am doing that maybe someone can see an issue with.
1) Dissolved silver alloy or silver composite (mainly from contacts but some sterling from candelsticks and jewelry as well) in 50/50 nitric/distilled water.
2) Filtered the solution using a few coffee filters. Water content is a little high from the rinsing of the glassware and filter.
3) Cemented with copper piping. Now using the silver plated copper wire that I melted (after melting, I used pH down, "Sodium Bisulfate" to clean of the flux). Left copper in silution and stirred every once in a while until no trace of silver when testing it HCL or sea salt.
4) Filtered and rinsed the cemented silver powder with lots of tap water (usually warm). Batch size was around 200g-300g.
5) Air dried the cemented silver powder.
6) Dumped it in a plastic container with other batches I processed.
7) Made some anodes from the bucket of silver powder by melting about 2 ozt in a clay melting dish with borax as the flux. Ususally I did not pour into a mold, but remover the silver from the dish and quenched in cool water. I would make about 7-10 at a time as I needed them.
8) Placed the anodes in the silver cell like in lasersteve's video with a stainless steal cathode.
9) Rinsed and harvested the crystals with DI water.
10) Cemented the silver out of the electrolyte and rinse water with the melted silver plated copper wire as in steps 3-6 above.
11) Rinsed the remaining undissolved anodes with DI water, and placed the cloth bag with the slime in nitric/water with enough (more than enough) nitric to dissolve any silver in the slime.
12) I rinsed the bag with DI water and dried for the next cell batch.
13) I filtered the solution and cemented the silver similar to steps 2-6 above.
14) Now when I make the anodes, they are mainly with silver powder that was recovered from the previously processed cell batches (I did notice that the cemented silver seems a little darked).
Electrolyte is made from havested crystal from previous cell batches.
Regards,
Tom