49089

Copper Electro-refining: All I get is copper powder/no adhesion to cathode  

June 22, 2008

I Have 250 lbs of silver/copper rocks. Some of the silver is as plain as Day visible
I built a mini electrorefining/electrowinning set up in a fan vented plastic 5 gal bucket.
I am using 5.17 volts DC /It was 18amps at 70 degrees/as the temp climbed, so did the amps/up to 90amps. electrolyite was now up to about 120 degrees. I was hopeing to sell the cathode as scrap copper/but all I collect is a micro-fine powder/I mean really fine/
like less than .oo1 inch particles. So I can't sell this as scrap copper and recover some of my cost...! I started with 1gal distilled water/5 lbs copper sulfate penta-hydrate
i.e. only about 2 lbs disolved/the rest layed in the bottom-oops!/ and I added 2.5 gal
of battery acid/1.265 specific gravity 33%...? I wanted to collect the sludge and use nitric acid to extract the silver/ estimate 7 lbs and about 1/4 OZ gold should be in sludge.... I just want to perfect the copper adhesion problem before I go any further.
So I can have about $700.00 scrap copper....so I can buy more of the silver bearing rocks
Cathode was .021 copper sheet wraped inside the bucket/cleaned with just alchol,to remove
any oil. Copper was orange/new sheet metal/ no green/but not sanded to brite fresh surface

I am technicaly inclinded...but, I am confident with proper guidence...I can make the copper adhere to the cathode....it just has to look good enough to sell as grade #1 copper
....unless there is a place to sell this Micro-Fine copper powder for more than $3.00 per lb...? If there is then, that would be even better like $5.00 per lb.
Thanks for any and all info...!!!! science frees us to do "Fun Things"....! maybe even profitable....!

Ethandrew Prater
newbie - Columbus, Indiana

It sounds like you've already managed to separate the copper from the rest of the sludge, any reason you can't just smelt it into ingots?

Marc Banks
Blacksmith - Melbourne, FL

Ethandrew,
Here's my second and final followup. I'm going to give you some basic information on casting and some links I've found to be helpful.
Firstly, this doesn't have to be expensive, you can make an expensive setup if you want, but it's not necessary. The highest priced item in what I'm going to lay out for you is going to be a crucible.
Go check out www.backyardmetalcasting.com

The heat.
Propane is cheap, regulators are inexpensive, and burns at a comfortable temperature. There are plenty of references on the internet about how to setup a good propane burner for high temperature applications. A forced air burner is the easiest to make.

The forms.
Also cheap as you're not casting extremely high temperature material. Go to the thrift store, get some steel muffin pans, poke around, see what you can find. Anything that is made from steel should work fine as a form. Do your pouring over sand anyway, just to be safe.

The metal.
Each of the metals you're working with here have varying melting points, you should be able to do some further refining (if needed) by keeping the setup at a constant temperature.

Good luck sir.

Marc Banks
Blacksmith - Melbourne, FL