Refining Gold

Refining gold, or cuprification (I think that's how it's spelled), was probably the most exciting part of the session I took with Jana Brevick.  I felt like a scientist and it was also somewhat powerful to learn this fascinating part of refining metal.

Here is a basic run down of how we performed our refining:  

Julia Heineccius, the studio assistant for the class also did a refining.  First you must weigh how much gold you want to refine and then multiply that number times 5 to get the weight of how much copper you need to add to the gold you already have. 

Once you have the clean copper weighed out you must melt it with your scrap gold.  Then clean and dry your scrap gold/copper alloy and put it in a large beaker.  

Then put the beaker under a very well ventilated area in a separate room, DO NOT do this at home, it is so dangerous.  I put on a face shield, plastic apron and long rubber gloves.  

I then added a decent amount of nitric acid to the gold copper alloy and watched the science happen - it was fun but amazing too.  You let the gold/copper alloy sit in the nitric acid solution for about an hour or two, then do the process again with clean (unused) nitric acid.  After two or three times the gold/copper casting becomes a sludge type of material.  

You then clean the sludge with water and let it air dry - once it is air dry you are ready to melt out the nasty sludge to reveal pure gold!!! See below for the step by step photos. 

The 10 kt gold I first 'refined' (aka cleaned).  Was my Aunts watch band.

My lil' baggie of gold, was about 8.62grams and my copper 41 grams.

Then I melt the 10 kt gold I had with the 41 grams of clean copper.

Excited faces (Julia, Keramit and Jana), we were giddy over doing this!

The two ventilation systems, this is a MUST, when you are refining gold.  The fumes are highly toxic.

Pretending to guzzle the nitric acid.  Don't you love my long black gloves?

This is what happens when you add the nitric acid to the gold/copper alloy. 

And this is what the 'gold' aka sludge looks like when you pour out the used acid.

Refining Gold from Eilisain on Vimeo.

And here we have my semi pure gold (23 kt). 

And there you have it my friends, how to refine gold.

There are still more Penland posts so stay tuned.
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Penland: Melt Class Post 2

Last week Jana showed us how to pour ingots and then make alloys of copper and fine silver.  As you know, I am a bit of a fan of melting metal and I truly enjoyed being a 'mad scientist' and creating my range of 7 alloy (some did samples from 9 parts pure silver/1 part copper and to the other end of the spectrum 1 part silver and 9 parts copper).

It's been very interesting watching the process of how the metal responds to forming, drawing out to wire etc.  What I've noticed is that the alloys at the higher end of the spectrum are more malleable and the ones in the middle, say 30/70 and 40/60 are more brittle.

This week we're finishing some pieces we made in class and also experimenting with gold alloys - which is so very exciting.  That'll be my next post and I'll share with you some stories about my classmates.

below are photos of Jana in action.

Thank you for reading!

Jana melting her metals (in kooky outfit - Jana's style)

The red hot ingot.

Pouring a sheet of pure silver ingot.

Jana showing us how to repair flashings from the ingot.

 

And Jana's wedding ring.  Lori Talcot made it for her...I'm a bit obsessed with it!

Silver and Copper alloys ranging from 10 % silver/90% copper to 90% silver/10% copper.

Some of our alloyed samples drawn into wire or flattened.

Iron and gold alloy...not sure what can be done with this, it's too hard!

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