# Refining in front of the customer



## Refiner232121 (Jan 17, 2011)

I went to a jeweler friend and I said I am doing refining and I said if he needs refining I can do his filling and polishing dirt.
He said he will give me some work 
He said he also has another refiner and this guy incinerates the polishing dirt in front of his eyes.
sieves it
Than he mixes it with white powder and than pour it into water.
He said he didn't know exactly what the guy was doing

What he is trying to say is that he is not going to give me his work blindly
This friend of mine is going to go on vacation and I don't know if I can speak to him for now 
In a very short time no one is going to refine anything in front of the customers eyes 
The thing I am wondering about is that was the other refiner giving my jeweler friend back his 10K gold 
in the polishing dirt

At that moment I didn't think of asking him this when I have the chance I ll ask
Can anyone give their opinion about this
Thanks


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## nickvc (Jan 18, 2011)

The first part of your post sounds like the normal way to treat polishing sweeps, incinerate,crush in a ball mill and then sieve to remove the large metallics. The white powder is probably lye which will remove the grease and organic material leaving a much reduced and easier to refine material.
The second part is easily answered. Your friend is only seeing the preparation of his sweep and it's not really telling him anything unless he's taking samples for assaying and he could easily do this part himself. I think it's highly unlikely that your friend is getting his gold back unrefined from this sweep as it's in very fine particulate form and to be useable will need refining probably twice to remove the unwanted dross.
I think that your friend is basically trying to find out if you know what your doing before giving you his sweep to refine. Be aware that sweeps are time consuming and and labour intensive and cost the job appropriately.


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## 4metals (Jan 18, 2011)

I have seen this done in downtown Manhattan. Jewelers would bring in a few pounds of sweeps and bench grindings to witness the burn out. The caustic leach followed by acid digestion in aqua regia and filtration and dropping the gold. Usually takes a few hours. The refiner melts the gold and buys it. Sounds like a great deal.

For years I processed the "refined" leftovers left behind by the jewelers as worthless. The resulting prepared sweep were far from worthless rarely less than 1/4 ounce of gold per pound. 

The "refiner" added a dilute aqua regia for too short a time to purposely leave values behind. 

Sometimes watching something you know little about can be futile.


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## Lino1406 (Jan 23, 2011)

Questions:
1. and then what?
2. sure he pours into water?


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## nickvc (Jan 24, 2011)

4metals that kind of agrees with what I found when I refined sweeps, say the first extraction liberated 75grams of gold the second would yield 7.5 grams or to put it simply there was roughly 10% left over. This was a useful guide as if the sweep yielded 25 grams the first time it wasn't worth the effort and time to extract the rest,this was back when fine gold was trading at the lows of the 1990s.


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## 4metals (Jan 24, 2011)

The difference is you were trying to get it all and they were trying to leave some profit. 

I think a pretreatment with nitric would yield better from a recovery standpoint.


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## Harold_V (Jan 25, 2011)

4metals said:


> The difference is you were trying to get it all and they were trying to leave some profit.
> 
> I think a pretreatment with nitric would yield better from a recovery standpoint.


I'd agree, but an incineration afterwards, then a wash in HCl sure does improve the handling characteristics of the material. 

The only time I used a nitric wash was when the material came from a silversmith's bench. Otherwise it was best to do the wash in HCl. A lot of iron is removed, but then it would also likely be removed with nitric. The resulting values were always difficult to filter, which lead to my second incineration and the HCl wash. The customer in question ran very little gold, but I was always able to make a recovery with that process. 

Harold


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