# Is SMB specific to the metal it reduces?



## ppoowweerr (Feb 25, 2009)

So I am beginning this whole scrap recovery, and I am very thorough in my processes. However I feel that my waste has some gold left in it. According to my SnCl4 test it does have gold in solution. As it is my waste container, it likely has other metals as well. So my question is:
Is SMB specific to gold? Will it drop out gold before other metals? Or is it an ionic free-for-all when the reduction begins?
Thanks for all the help!


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## Noxx (Feb 25, 2009)

SMB releases SO2 which precipitates (drops) only gold (and traces of other PGMs)


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## ppoowweerr (Feb 25, 2009)

Thanks Noxx! I hope it wasnt too much of a noob question. Does Hokes mention that and I missed it? 
Thanks again!


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## qst42know (Feb 25, 2009)

Hokes suggests a stock pot for what to save and what not to. And how and when to process.


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## Harold_V (Feb 26, 2009)

ppoowweerr said:


> Thanks Noxx! I hope it wasnt too much of a noob question. Does Hokes mention that and I missed it?


It's been a long time (_many_ years) since I last looked at Hoke. She may not mention SMB, but does mention SO2, which is what does the work. It is selective in precipitating gold, but my experience indicates that it also precipitates traces of palladium. Drag-down does not appear to explain the higher percentage that I experienced, very unlike platinum. My results in precipitating gold that was mixed with palladium was consistent. The gold came down dark brown, always, and always had a showing of palladium. 

Harold


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## jamthe3 (Feb 26, 2009)

Harold,

Did the palladium get removed w/ the subsequent HCL washes or did you use nitric also?

John


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## Harold_V (Feb 26, 2009)

jamthe3 said:


> Did the palladium get removed w/ the subsequent HCL washes or did you use nitric also?


My experiences left a little to be desired. I washed my gold ONLY with HCl (never nitric), due to the risk of re-dissolving gold that had come from a chloride solution. The washing procedure was not adequate to improve the quality of gold to my liking when palladium was present. Instead, all gold so contaminated was used as my added gold when evaporating. It got melted to a button for easy handling and was kept separate from the balance of my gold. I seemed to achieve a balance of sorts, always having a few ounces of buttons on hand, but never a large overage. 

I don't know if washing with nitric would have improved the quality adequately, or not. Washing, at least by the method I used, while very important, will not yield high quality gold when it starts life quite contaminated. It improves it dramatically, however. It appears that atoms of palladium got entrapped in the gold, although I don't know that to be the case. All I do know is washing was not enough. 

I found the only way to improve quality beyond that stage was to re-dissolve the gold for a second precipitation. It could also be parted in a gold cell, but I never got mine operational, finding that a second refining yielded the results I sought. By then, the contaminants are at such a low level that very little is dragged down. A second refining yields wonderful quality, as you might see, below. The gold pictured was not pickled---it was bright and shiny as cast. I don't claim 4 9's quality, but I believe it to be very close. 

Harold


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## jamthe3 (Feb 26, 2009)

Okay, so the palladium was dragged down when the gold precipitated...it was precipitated also w/ the SO2 and the second time around there's so little left that drag down isn't as much of an issue, if any at all.

Beautiful picture, did you melt the powder in your furnace & pour as shot? Absolutely gorgeous.

BTW, thanks for taking care of that other thread...it was disturbing; & thanks for all the generously dispersed "gifts" you & so many others provide with ya'alls posts. Its greatly appreciated.

Noxx, for such a young man...you really came up with a winner here.

Cheers,
John


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## SapunovDmitry (Feb 26, 2009)

So all contamination comes from small particles of other metals that stay on the filter after filtration?


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## Harold_V (Feb 26, 2009)

jamthe3 said:


> Okay, so the palladium was dragged down when the gold precipitated...it was precipitated also w/ the SO2 and the second time around there's so little left that drag down isn't as much of an issue, if any at all.


Yes, that's my assessment, but remember that I am a person without education and lack knowledge in chemistry. They are conclusions I've drawn by deduction, and are just as likely to be wrong as right. One thing is sure, though, when palladium is mixed with gold, you can expect to deal with both of them, even with selective precipitation. 



> Beautiful picture, did you melt the powder in your furnace & pour as shot? Absolutely gorgeous.


Thanks!  

I've posted it so many times that I sometimes hesitate to do so again, but there are new readers on a regular basis, and it's a great picture to encourage others to concentrate on quality. That was my greatest concern, bolstered by one of my very first customers who had used some poorly refined gold and ended up with a large number of custom carved rings that had been cast with brittle gold alloy. He turned to me to have the gold refined quickly, and became one of my most steadfast customers. I served him until the day I sold the business. 

I didn't melt by furnace. I found it to be less than convenient, even when I had a large volume of gold to melt. The last time I re-refined gold, just before selling my humble business, I melted just over 400 troy ounces (part of which is in the picture you saw), all by torch. That was the exception, however. I normally melted somewhere between 70 & 80 ounces in a single lot, which was the typical amount of gold I re-refined as a batch. All of the gold I dispensed was refined two times, to insure quality. 

I melted in roughly 10 ounce lots, using a large Hoke torch. The melting dish was then poured to a second dish that had an orifice in the bottom. That dish dispensed the molten gold in a fine stream (1/8" diameter) to a deep stainless catch basin in which I had a circulating pump to stir the water. That prevents localized areas from turning to steam, allowing the molten gold to hit the bottom of the container. 

A second torch played on the second dish constantly, keeping the opening from freezing over with gold. In order to pour shot instead of cornflakes, you must not pour over the lip of a dish. 



> BTW, thanks for taking care of that other thread...it was disturbing;


I had already concluded that it would die, while mulling it over as I worked on my house today. The response is unusual----rarely do I encounter someone that must win the battle, even at the expense of losing the war. I am not a very forgiving type of person. Once set off, it takes a great deal to get me to come around. If often never happens. 

I thank you for your comments (in regards to the thread in question), which were very appropriate, and to the point. 



> & thanks for all the generously dispersed "gifts" you & so many others provide with ya'alls posts. Its greatly appreciated.


On behalf of the others that give so generously, you are most certainly welcome. 

I derive a great deal of pleasure from trying to help others. I remember all too well how no one would provide the smallest bit of information when I was trying to learn how to refine. That includes a local refiner that laughed in my face and told me I'd never learn. I eventually gathered all of his customers as my own. The bulk of my learning came at the expense of constant research, and reading Hoke. 

Because it was illegal to refine prior to '75 (a federal license was required), and the secretive nature of the refining world, very little information is available in a format that can be used as a learning tool. Most of the information I uncovered was technical in nature, with little or no information on the actual process of refining. Hoke's book is truly a treasure, although many don't grasp the significance. Hers was the only act in town until the late 70's, as I recall. 

Harold


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## Harold_V (Feb 26, 2009)

SapunovDmitry said:


> So all contamination comes from small particles of other metals that stay on the filter after filtration?


Not exactly. The contaminants in question (palladium, in this case) are carried through filtration as a part of the solution, as you would expect. When you precipitate the gold, some of the palladium appears to be precipitated along with the gold. 

It is normal to have drag-down, but everything I experienced indicates that there is more than dragdown when palladium is involved with gold. 

I welcome anything that would better explain what I experienced. I don't claim to be sure of what I have said. 

It might be good to mention that I dealt with the platinum metals on a fairly regular basis, due to processing dental wastes. It was not unusual to have my customers include old dental appliances in their wastes. 

Harold


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## ppoowweerr (Feb 26, 2009)

So if palladium seems to be an issue sometimes, could I add the SMB dropwise over a longer time to minimize a localized excess of SO2. I would think that a little patience on this step could do the job, or would i be wasting my time?


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## goldsilverpro (Feb 26, 2009)

Harold,



> Because it was illegal to refine prior to '75 (a federal license was required),



I started refining in the mid 60s. If I remember right, the licensed refiner (supposedly) had to report any inventory over 200 oz. In '72, I owned half of a small refinery. We had no license and no one one ever bothered us. The buying and selling of pure gold went on the same as it does today. When we sold gold, we had dozens of large buyers to choose from. It was all done in the open. In about '73 (I think), the gold price was allowed to freely float. I think that, in those last few years, there was little enforcement of the gold laws and no one paid any attention to them.


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## Harold_V (Feb 26, 2009)

That's interesting. I had procured a copy of the regulation that controlled gold and was horrified at the penalty, which was ten years in prison and a ten thousand dollar fine for a conviction. 

Not having a clue if the law was being enforced, or not, I kept looking over my shoulder as I learned to refine. It was only after the regulations were abandoned in January of '75 that I started breathing a sigh of relief. That was also instrumental in my simple hobby becoming a business (that was not planned). Because it was no longer illegal to refine without the license, jewelers that had been locked in to major refiners to deal with their wastes were eager to find local service. Fact is, I was lucky-----I was in the right place, at the right time.

Harold


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## JustinNH (Feb 26, 2009)

Harold_V said:


> That's interesting. I had procured a copy of the regulation that controlled gold and was horrified at the penalty, which was ten years in prison and a ten thousand dollar fine for a conviction.



Holy mackerel


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## Oz (Feb 26, 2009)

That’s what happens when governments confiscate gold from their citizens in like in the US in 1933. It is worth noting how many chose to take the risks despite the penalties. Remember what a $10, 000.00 fine was back then compared to now. Some fear that a confiscation like that could happen again and even include silver. It would be one way to support the dollar giving our government something of worth and eliminate the option of precious metals as currency, forcing the use of our paper fiat dollars.


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## jsargent (Feb 26, 2009)

Harold_V said:


> That's interesting. I had procured a copy of the regulation that controlled gold and was horrified at the penalty, which was ten years in prison and a ten thousand dollar fine for a conviction.
> Harold



I remember watching an old episode of Hawaii Five-O where they were after and caught (of course) a dastardly band of unlicensed GOLD DEALERS :shock: Saints preserve us, can you imagine any activity more heineous than the buying and selling of gold? It's hard I think for younger people to realize that it really was a serious crime back then to be involved in gold unless you had the stamp of approval from Big Brother. 

Remember the fellow in New Mexico who discovered an enormous cache of Spanish Gold in a deep cave and he had no way of legally selling the bars he carried out? He even went so far as to petetion Congress to make an exception in his case but with no luck. The US Military ended up seizing the hill where the cave was and they hauled it out to who knows where.


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