Gold refining secret from karat jewelry

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In most cases it is nearly impossible to acquire HF due to it high toxicity. Most people may know it as the stuff vandals use to scribble on windows as it permanently frosts glass.
Hencewise this frosting will work on most gemstones and leave diamonds more identifiable.
 
SilverNitrate said:
In most cases it is nearly impossible to acquire HF due to it high toxicity. Most people may know it as the stuff vandals use to scribble on windows as it permanently frosts glass.
Hencewise this frosting will work on most gemstones and leave diamonds more identifiable.
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That's what diamond testers are for.

The idea of recommending the use of HF in that capacity is way beyond anything that should be posted on this forum, although I intend to leave it as a reference.

Please do not lose sight of the fact that almost none of these guys work with a fume hood, and some don't have enough wisdom to wear proper protective gear. Suggesting they use of HF is akin to telling them to work with cyanide when they have no clue.

Be careful, folks. It's easy to get injured working with these reagents, as you all, I'm sure, already know.

Harold
 
Hoke even mentions the use of HF. On page 182 it is suggested as the method of removing sand, enamel, porcelain and glass from platinum filings or iridium powder.

Better to educate in the proper function of any device, substance or item rather than to make it a boogy man in the closet. The fools of the world will obtain and abuse what they will, no matter what the warning or advice.

Those with a more legitamate uses will benefit more from the education than from the stop signs, and will obtain and use if there is a need anyway. I hear the same junk about guns all the time too. A tool is a tool, and the only difference is in the use.
 
I agree with AkDan saying that everything is a tool. The only thing is that HF is an extremely dangerous tool, and you can probably come up with something so you don't have to use such a dangerous tool.
 
AKDan said:
Hoke even mentions the use of HF. On page 182 it is suggested as the method of removing sand, enamel, porcelain and glass from platinum filings or iridium powder.
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Sadly, she also recommended tossing on a generous amount of gasoline when incinerating. I surely wouldn't support her with that recommendation, either. I have a lot of faith in her book, but keep in mind that it was written when few, if any, regulations prevented people from being stupid.

Better to educate in the proper function of any device, substance or item rather than to make it a boogy man in the closet. The fools of the world will obtain and abuse what they will, no matter what the warning or advice.
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The very reason I intend to leave the post with the recommendation. Readers may become aware, but they will not get encouragement from those of us that understand the unnecessary dangers involved. I want evidence presented that those of us on the board that advise are advising against it. This isn't strictly about handing out information that may or may not be useful, it's about giving a recommendation that isn't necessary, and has a high risk of harm.

Those with a more legitamate uses will benefit more from the education than from the stop signs, and will obtain and use if there is a need anyway. I hear the same junk about guns all the time too. A tool is a tool, and the only difference is in the use.
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I agree, but fools will interpret the suggestion as something that could benefit them in some way, get harmed, then attempt to hold everyone but themselves responsible. I refuse to place myself, or Noxx, in that position. I do not endorse any process that is high risk, and serves no useful purpose, particularly when there are alternate courses of action that offer no risks at all. We are not here to temp idiots, we're here to, hopefully, provide information that is practical and useful for those that enjoy recovering precious metals. Damned few, if any, need worry about a "method of removing sand, enamel, porcelain and glass from platinum filings or iridium powder" These are not elements that the vast majority will encounter, and few of them will deal with filings, anyway. I refined for well over 20 years, and used HF for one reason and one reason only------and that was a rarity. I used it to pickle platinum buttons, in a small platinum dish. It is safe to say that in all my years of refining, I used a grand total of a couple fluid ounces, and I refined on a regular basis, 7/24/365.

We have to be a bit careful on this forum to not provide instructions that are obviously unnecessary----and can prove to be quite harmful. Working with HF is one of the things that we don't need, and should not promote. Those that feel they need it can go elsewhere for their knowledge. Here, they are advised to not use it. If they are child enough to not follow good and proper advice, I sure as hell don't want to advise them to use HF for any reason. I think I speak for at least one of the other moderators in that regard, and perhaps both of them. GSP has an attitude about HF such that he won't even mention it by name. He's a well educated and experienced refiner. There's a message in that for anyone with brains.

Harold
 
It's nasty stuff through and through, but it has its uses.


A safer alternative to working with HF is to use ammonium bifluoride. It is a solid, if kept neutral it will not form any HF. You can form HF in situ by adding H2SO4.

The convenience here is that this can be dissolved into water, and then poured over whatever one wants to digest. Then one would add sulfuric acid until they see material dissolve. This eliminates the pouring of HF, or the dilution of concentrated HF (a very mobile liquid, easily sloshes about).
 
Thank you for the reply Harold, and in reality I agree with you and all of your reasoning with regard to this subject. Reading through the many posts throughout this board I find myself in wonder at some of the operations and tactics people are chosing to use. I am amazed that there are not more stories of illness, injury, or death with respect to some of these "OK, this is what I did" stories.

Lou, thank you for the follow-up and what seems to be a much safer alternative to producing, and working with a dangerous substance.
 
Yes, calcium hydroxide. You will get CaF2 precipitate, pretty stable stuff. Just keep it away from acid.


Lou
 
I believe he said in the original post that the HF was just a way of testing diamonds(as dangerous as that my be). I would like to hear more on his GOLD refining technique,(WHICH DOES NOT INVOLVE HF)
 
I would not use it to test gemstone in jewerly because even though it may not affect diamonds what about other jews? I would think that gold or pt jewerly would rarely have glass as the gems maybe amethis(sp) or other semi precious.
 
There's a lot of gold jewelry containing CZ's. As a jeweler and active purchaser of old jewelry, I deal with these almost daily. The easiest solution we've found is seperate pieces with CZs and diamonds and refining them seperatly.

A problem I have a the moment is that we had a glass container with approx. 3 oz of gold mud dropped on the floor. We strained most of the glass out, but still have very small particles of glass in the unmelted mud. Other than using HF, are there any recommendations to separate the glass from the gold? I'm thinking maybe we should just melt the mud and refine. Would this solve the problem?
 
Just dissolve it in HCl/Cl and re-precipitate it. The glass won't dissolve.

If you melt it, it will take that much longer to digest it and you will end up having to use AR.

The HCl doesn't have to be concentrated, in fact, above .5 Molar HCl, the solubility of Chlorine decreases. Heating it also drives off Chlorine.

This Winter I did tests on HCl/Cl and it even worked well at Minus 20 Centigrade.

Take The Gold powder and put it in 2 equal volumes of HCl, Add a few drops of Chlorine bleach to generate Chlorine. If you add too much bleach, the Chlorine will just boil off and be wasted. You can always add more HCl later.

I prefer using 1/3 strength HCl and adding just enough bleach to make the solution cloudy. When it goes clear again in several hours, I add a little bit more.

Don't do this indoors unless you have a fume hood.

lasersteve has a video on the process.
 
Personally, I would just melt it with extra borax. The borax will melt and react with any glass, which will float to the top and can be skimmed off or preferably broken off the cool button.


I had something similar happen to me with platinum black and some glass that got into it (broken stirring rod) after spending about 20 minutes trying to pick out the little flakes of glass, I just decided to use ammonium bifluoride and some sulfuric acid to remove the glass, then dry the Pt. Worked like a charm!
 
I'm sure it's contaminated from being on the floor. You need to re-refine it so there's no reason to melt it. Just dissolve it in minimum aqua regia, dilute 3 to 1, filter, and go from there.
 
Thanks for all the suggestions/advice and great info. I did refine it without melting. Good results with a beautiful shinning 1.9ozt ingot. I lost a small amount
 
Don't quite know what happened my last post posted while I was typing. I lost a small amount still on the floor somewhere, but was relieved with the results I finished with.
 

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