# Pipe, purity, button size?



## MGH (Jun 6, 2015)

Hi all,

I have a relatively simple question, followed by some back story and a more open question. I'll try to be concise.

The simple question: Does this button look good and pure, 9995+? This is my own button, I refined it from plated pins. I do want to sell it, but have to take a pause here before I dogmaticly assert its purity.

The reason for the pause: I typically sell refined gold to a local buyer who uses his own XRF for a quick analysis. The last time I sold a 1+ ounce bar, we actually met at a central location and he paid outright without any analysis, as we had done enough business before. The next day he sent a snapshot of the XRF reading showing about 1% platinum content. I had to tell him I had no idea how that could be, and frankly defended my purity. I digested the pins (Kovar base metal) in nitric, then twice refined the foils in AR, dropping with SMB both times. He wasn't making a big issue about it. I offered to buy back the gold, but he was already planning to send it in to his refiner, he did, and that was the end of it.

Now I have this 15.04g button refined from the same type of pins. Yesterday the buyer analyzed using his XRF, and again it showed some platinum as the primary contaminant. It then also showed some germanium as the primary contaminant depending on where he shot it. It always read at least 98% gold, but the contaminant readings were not at all consistent.

The more open ended question: What are the possibilities I have selenium or tellurium in my gold and the XRF doesn't know what to do with that signal? Complicating things a bit is the fact that the XRF bulb is old. This buyer knows that, and knows XRF can be missleading anyway. Of course the thing to do is analyze some known 999 bullion and see how it reads. He didn't have any on hand yesterday (at his home), so we'll have to do that later.

I do not know the exact source of the pins that I refined. I do know they are not from consumer or even telecom computer equipment. They are even higher grade than that. I'm sure this still leaves some holes in the story, but I'm wondering if anyone has some insight into the issue. I want to sell the gold, but I want to make sure I'm selling pure gold.


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## g_axelsson (Jun 6, 2015)

Bring a gold coin of known purity to see if his XRF is calibrated correctly.

Göran


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## patnor1011 (Jun 6, 2015)

My thoughts exactly. It may be quite easy to get one of those sealed in plastic card 1g bars and have a go at it with his XRF. It may not be calibrated properly.


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## MGH (Jun 8, 2015)

Thanks guys. Comparing against some known bullion or coin will definitely be the next step.

I forgot to ask another part of the question relating to the title of this post. The buyer commented after seeing the odd results from the XRF that this button might not look quite as pure as the previous gold I’ve sold to him. His comment was something like “Hmmm… and this just doesn’t look quite like the other gold you’ve refined. This one isn’t all caved in on the top”

So my question is regarding the degree and type of pipe one would expect for different sized buttons of the same purity. Surely at one ounce or more, the top of the button should be concave. But at 1 gram, the button would be convex, almost a hemisphere. My current 15 gram button is convex across the top, but has some cracking and a deep pit where the nice golden-orange color shows. Should these characteristics lead one to believe the gold is very pure, even if the top of the button is not concave?

Also, last question, if the gold really did have on the order of 1% contamination of some other metal, would it still be possible to have the appearance as above, or would it be frosted, without any cracking?

Thanks all.


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## Lou (Jun 8, 2015)

XRF confuses selenium for platinum. FYI, SMB or sulfur dioxide precipitates Se from aqua regia. Be careful, very careful when melting anything with Se. 

I highly doubt there is 1% Se in there; Se in even minor amounts usually causes frosting, and I can literally smell it in the gold sponge if it is present. 

If you melt the gold with a very hot oxidizing flame and there is a black or red sublimate in the dish, that is your SeO2 that has burned out of the gold. 

Lou


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## MGH (Jun 12, 2015)

Thanks Lou. Here's some more information. It kind of does look like selenium could be involved. Can you take another look?

It turns out that when I melted the button above, a few beads of gold remained in the dish. The first picture is the dish with the beads stuck in it. I had noticed the pink color, but from reading on the forum thought that was normal even with pure gold. Tonight I went back for the few beads and melted with an oxidizing flame as suggested. I played the bead around in the middle of the dish for a little bit and then plucked it out.

There does appear to be a more intense red/black color after re-melting that little bead. I haven't smelled anything unusual in the gold sponge before, but then again I haven't been sniffing it either. Lou, is there any way to describe the selenium odor? Does this dish look like it indicates selenium contamination?

Thanks


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## patnor1011 (Jun 12, 2015)

Maybe it is just my monitor playing tricks but I see some green there too.


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## Lou (Jun 12, 2015)

Looks like the torch pulled something out of it. Can't be sure. Is it red not purple in the dish?

Se smells like a weird cabbage nauseating funk. Very detectable.


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## MGH (Jun 12, 2015)

I'd say it's more purple - at least if you're asking after seeing the picture, then yes, it's purple rather than red. Even though I don't typically sniff my gold sponge, I am pretty keen on odors and I'm pretty sure I've never detected any stinky cabbage.

Pat, in the pictures I suppose you could see a little green there, but I think it's just the lighting and the photo. There really isn't any green in real life.


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## Lou (Jun 12, 2015)

Might be time to paint the dish in carbonate solution 




I think your gold is probably fine. If it rolls and doesn't crack, no lead and probably no Se


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## MGH (Jun 12, 2015)

Lou said:


> Might be time to paint the dish in carbonate solution


For sure, won't be melting any more pure gold in that one just yet.

Thanks so much for the help and insight.


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