Non-Chemical Refining 22K gold

[BusinessMan]

I am thinking that the proper way to refine this would be to reduce 22K to 6K but I am not sure about that
Or if you have gold from the polishing dirt and it comes out clean but it is 9995 do you also reduce this to 6K
Thanks

 

[nickvc]

With high grade karat gold it's better to just refine as is through AR and use good filtration and washes to reach high purity, most of our methods are about removing base metals and silver before going the final refining with 22k your almost there.
With your sweeps I feel that if you are getting .9995 purity you would struggle to get any higher without extra costs and electrolytic refining techniques, wet or chemical refining will rarely reach better than .999 so I'm not sure what you want to achieve....
If your wanting .9999 then you won't reach that by chemical refining, it will involve extra costs and the use of a cell and a big investment in keeping the gold in your solutions there constantly to achieve your goal

 

[BusinessMan]

Hi Nickvc
Thanks for your reply
I thought it was possible to have 9999 by chemical refining like we know it here.
AP process and I thought Harold was getting 4 nines and he was also making gold bars and usually they I 4 nines or maybe he was marking them 9995.

 

[4metals]

There is a large commercial refiner in the US getting .9999 by refining karat twice in aqua regia. The major contaminants between .9995 and .9999 are copper and silver, and they are usually picked up in the rinsing because the base metal contaminated acid and some of the silver chlorides are hard to rinse free. Refining a second time produces a waste liquor which is almost barren of other metals so the contamination from insufficient rinsing is less.
It doesn't take a lot of contamination to lower .9999 gold to .9995.

 

[Harold_V]

Hi Nickvc
Thanks for your reply
I thought it was possible to have 9999 by chemical refining like we know it here.
AP process and I thought Harold was getting 4 nines and he was also making gold bars and usually they I 4 nines or maybe he was marking them 9995.

I am not convinced I ever achieved 4n's quality, although I do know I was very close. I marked my ingots as fine gold, which provides a comment that the gold is not intentionally alloyed. Needless to say, there is no such thing as pure gold, although one can produce gold of exceptional quality with some effort.

I agree with Nick. If the 22K gold is alloyed with copper, it's a non-issue--it will dissolve readily in AR. If it is alloyed only with silver, it will still dissolve, although the presence of silver will be all too apparent. If your goal is high purity, inquartation in either case would be in your best advantage----although a second refining of the resulting gold will always improve quality immeasurably.

It is my opinion that the average guy, refining in his humble lab, isn't likely to achieve 4n's quality unless a Wohwill cell is employed. Even then, how the gold is handled in melting and pouring can still result in lower quality. Achieving 4n's is not something that is done easily.

Harold

 

[goldenchild]

Attached is a read out of twice wet refined gold.

View attachment mrj top.pdf

 

[4metals]

It is easier to make high purity gold when processing large lots, the smaller the lot the harder it is.

I don't have an ICP at my disposal but it would be interesting to start out with .9999 or better gold (an uncirculated Maple Leaf) and melt it into a button. It should have the pipe on the surface. Then add copper in very small increments to make it .9995 (verified analytically) again melt and see if a pipe develops. Continue adding copper and analyzing the alloy to see at what purity the pipe disappears.

That would be a nice thing to know.

Then for S&G repeat the experiment with silver as the contaminant and see if the results are the same.

 

[Oz]

I would imagine that there is a good bit of variation as how pure you need to be and get a pipe. Take the example of plucking a button from your meting dish as soon as it is cool enough to do so. Now imagine if one button is 10 grams, and another is 5 oz Troy. The cooling rate will be very different whether air cooled or plunged into water.

Kinda like you can finesse .9995 gold to not form a pipe if you wish.

It would still be neat to do an apples to apples comparison with the same mass/different purity using the same cooling parameters.