Electrolytic cells and smelting

[4metals]

But i think our furnace does rotate very fast

This can also be an issue as you want the pool of metal to form and remain in the lower part of the rotating furnace, fast rotation will increase the level of metal in your slags. One way to minimize this can be to stop the rotation and let the metals settle before pouring.

 

[Alondro]

@Alondro please do share if youo have been able to do this

It'll be a while. I have to get a list of the exact types of fittings and pipes I need to build the gas burner with the air blower. It's my first time constructing such a furnace, and I want SPECIFIC protocols. I was a research scientist for 17 years, and I don't do ANYTHING complicated without a written protocol!

I'm also quite busy at the time... and having to start scheduling a hernia surgery. So, yeah, not doing anything intensive until that's finished and the abdominal muscles have healed.

 

[Ayham Hafez]

Not all hobbyist refiners have XRF reader to read anodes each time, or like me I can't find the proper material to make oxygen purging, so let's say we are processing 90% to 96% copper anodes, at the end we will get a concentrated tin sulphate in the slimes, I'll not discuss wet processing of the slimes, I will assume that slimes are too much to be processed in wet method.


After drying the slimes, I don't waste time to fully wash them by water cause filtering slimes is really a big issue, I just put the slimes in steel bowl and roast, then mill everything after that I add the following fluxes:

2 parts soda ash
0.5 part borax
0.25 potassium nitrate
0.25 lead oxide
0.1 charcoal powder
0.05 iron nails added after potassium nitrate been melted or consumed.


Yes, I reduce everything, when I started processing slimes I was trying to oxidize as much base metals as I can but noticed that most of the gold will go into the matt layer, roasting will not oxidize sulphates such as tin and copper sulphate, so we have to oxidize them while smelting by adding oxidizer like potassium nitrate, iron and lead alone will not displace copper in copper sulphate form.

After pouring the molten I go to cupellation process, with this method I recover 99+% of precious metals, I have did many fire assays and noticed that even we have a small matt layer we will loose some gold, in another word gold like to stuck into sulphate matt.

 

[Marcel]

I mean that sounds simple enough, but nothing is that straightforward in practice. I've seen so much information here and other places saying that slimes are a real pain in the neck since colloids are like wet clay and get everywhere. And of course I watched sreetips go through so many steps to try to work over the silver cell slimes. I think it was you also who said that melting slimes into a dirty button will only complicate things. Also spending a lot of effort and reagents for a small amount of gold, the danger of platinosis, the risk of spills and contamination when under the hood makes me leary of doing that if I don't have to. I'm not intimidated by it, just seeing if there is a way to lessen it.

I know there is no easy button and I'm not trying to push my ignorance, but is there any merit to what I'm proposing? Just avoiding the mess and getting the material into a crucible and using a collector metal which you then use as an anode in a different cell, just recycling the slimes in order copper, silver, gold, and back to copper.

At the risk of overstating my case, if well sorted e waste is trace PMs and mostly copper, the slimes are some copper, some silver some gold and whatever insoluble junk. If most of the trash goes into the slag and the silver would collect the gold, the it would leave it in the silver slimes. Then use gold karat scrap to collect the gold from the silver slimes, leaving silver and whatever else in the gold cell slimes. Smelting that in with more e waste copper would just marginally increase the PM content and wind up in the slimes again, and come out as silver crystal in that cell.

Is this making sense? If I'm barking up the wrong tree let me know.

Like @Yggdrasil said, you’re already on the right track (I’m currently building and running some copper cells). Stick to wet chemistry and forget about remelting the materials. This isn’t natural ore, no need to oxidize the material add collector silver etc.—you already have very fine slime or dried powder, which is ideal for further, highly effective processing.


Just be sure to extract as much copper and other base metals as possible. You might want to let the process run for a very long time—days or even weeks—or repeat electrolysis multiple times. Each cycle will purify your anode slimes further.


Remelting and producing slag will only cost you time, energy, and money, leading to losses in the slags and crucibles. Stay on the course you’re on—it’s very effective!