# jewellers polishing dust question



## profex (Nov 5, 2011)

Hi all!
New to the forum, but I have been an active bench jeweller for the last 20 years, and (at one time) did some of my own refining, but always from solid gold waste from my jewellery repairs and manufacturing. Basically "the easy stuff".

One thing I have never been too keen on refining myself has been polishing dust from my dust collector setup. It seems like a bunch of mucking around, and my busy schedule just makes using an outside refiner a better choice for my polishing dust, but I have my concerns with what return I should expect.

WHICH BRINGS UP MY QUESTION.

What would be considered an industry "standard" of rate of gold return per kilo of polishing dust? I know that it will vary depending on the collector system, the goldsmith's percentage of gold vs silver work, and if grinding is done at the polishing station. But there must be some sort of data out there.

does anyone here have any experience with some "typical" scenarios for percentage of return within that part of the refining industry?

Thanks in advance


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## goldsilverpro (Nov 5, 2011)

About 10 years ago, I worked with a couple of people that bought and processed a lot of buffing dust. Some of the lots weighed 200-300 pounds. I mainly did the assaying of the prepared sweeps but I was also involved somewhat in the preparation. At the time, the gold spot was between $275-$350/oz. At that low gold spot, good buffing dust could run about $100/pound, as received, and, once or twice, I saw it at maybe $200/pound. It could also run $20/pound, or less. In general, it ran all over the map. It mainly depended on 3 things: (1) What metals or alloys did the jeweler work with? (2) How well did the jeweler keep the batches of buffing dust, from working with gold, silver, and platinum, segregated? If the jeweler worked with all different karats, silver, and platinum and, if he mixed all the buffing dust together, the value could be anything. (3) How clean was the buffing dust? If there was all sorts of junk in there, like cigarette butts, steel wire, floor sweepings, etc., the value would be lower, of course. Also, if there were a lot of worn out wooden brushes in there, the value could be low.

One guy I knew got pretty good at ball parking it by examining a bunch of samples with an eye loupe. However, the best he could do was to categorize it as low, medium, and high and, sometimes, he was way off. Also, it's virtually impossible to sample this stuff accurately and assay it. What you get is what you get.

Harold and 4metals have a lot more experience with this than I do. Maybe they could chime in.


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## Harold_V (Nov 6, 2011)

Can't speak for 4metals, but in my experience, there's no such thing as a standard yield. Not even close. Sort of like running a carpet. So many factors influence the end result that it's simply impossible to make a respectable estimate. How the benchman works makes a huge difference. Some do a great deal of finishing at the polishing lathe, while others do that work at the bench, and bring up the final luster only on the wheel. 

One thing I will say-----you most likely have been giving up a considerable amount of your gold to the refiner. One of my customers got baptism by fire in that regard. He was strictly a gold smith, yet his return of silver exceeded the return of gold by a huge margin when he submitted his wastes to Eastern Smelting and Refining. His thoughts were that he had been ripped off. As a result, after that experience, he sat on his polishing wastes and filters until he had accumulated a considerable amount of each. He finally entrusted me to process for him and was shocked at the return, confirming his thoughts that he had been thoroughly ripped off.

While processing polishing wastes and filters was far more labor intensive (I charged 15%), rarely was it not worth the effort. 

If one is to decide to process these materials, incineration is extremely important. There can be losses to dusting, so a filtered hood is required, as well as one that won't burn. That (fireproof hood) was a lesson learned the hard way. 

Harold


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## profex (Nov 6, 2011)

Thank-you for your replies. I guess I will have to find a reputable refinery in Canada for this bunch of polishing dust.

Any suggestions?


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## goldsilverpro (Nov 6, 2011)

profex said:


> Thank-you for your replies. I guess I will have to find a reputable refinery in Canada for this bunch of polishing dust.
> 
> Any suggestions?



When it comes to unprepared buffing dust, the term "reputable refinery" can be an oxymoron. In my experience, the greater the "gray area" in a lot of material, the greater the opportunity for the refiner to steal, if he so desires. No one, including you and the refiner has any idea of what this stuff is worth until it is processed. That's why the refiner is sometimes called the "last liar." Any guesses could be several hundred percent off. I know of nothing that has a greater "gray area" than unprepared buffing dust. And, you can't sample and assay it unless you "prepare" it first. When you ship prepared dust, the refiner knows that you know. When the dust is unprepared, he knows that you don't have the foggiest idea of what you have. Thus, he has a license to steal, if he so desires.

Here's a crazy analogy that a refiner friend of mine liked to use. Very hypothetically, let's say you have a sealed envelope of money. There might be $100 in there and there might be $10,000 - you have no idea. You don't want to take the time to count it, so you pay some guy 10% to take the envelope into a closet and count it for you. This guy knows that you have no idea what's in there. Duh!

Preparing buffing dust basically involves incineration, grinding, screening, and magnetic separation. In each of these steps, you really have to know what you're doing and be properly setup for it. During and after incineration, this is the dustiest stuff I know of and much of the values can be lost in the air unless they are properly confined during the different operations. After preparation, the dust can easily be sampled and fire assayed. When we shipped prepared dust, the settlements were most always within 2 or 3 percent of my assays and were within the agreed upon splitting limits. Settlements are a game and, of course, the refiner was always a bit on the low side.

If you ship unprepared buffing dust and, if you're very, very lucky, you'll find someone like Harold that will only take what he agreed upon. These guys are few and far between, though, in my experience.

If you have enough material, it's often best to split the lot, as evenly as possible, and ship to 2 different refineries without them knowing you are doing this. They may both steal, but at least you'll have an idea of which one steals the least.


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## profex (Nov 6, 2011)

Hmmmm. Thats kind of what I suspected when it came to this sort of material. 
A "golden" oppertunity for the dishonest.
Perhaps I may want to consider researching those preperation processes here, and spend a little time doing some basic leg-work to help insure fair treatment by a refinery.


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## goldsilverpro (Nov 6, 2011)

Search for polishing dust, buffing dust, and polishing wastes on the forum, especially for those posts written by Harold_V or 4metals. 

The Hoke book has information on working this material. Here's the download.
http://goldrefiningforum.com/phpBB3/download/file.php?id=2480

In Loewen's excellent, but seldom mentioned book, there is about 50 pages on working with buffing dust.
http://www.lmine.com/mm5/merchant.mvc?Screen=PROD&Store_Code=LMS&Product_Code=17208&Category_Code=assaying


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## star122552 (Jul 13, 2017)

You need to try https://www.youtube.com/watch?v=zpIw3zYJblI
Good luck.


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## Topher_osAUrus (Jul 13, 2017)

star122552 said:


> You need to try https://www.youtube.com/watch?v=zpIw3zYJblI
> Good luck.



Pretty old thread..
But, your video you are quite proud of (to post multiple times), is ripe with poor practices.

Why did you go straight to AR, instead of doing nitric first?
-so you could get the silver instead of converting it to chloride form?

Why did you use urea, which can cause problems of its own with platinum group metals and waste treatment?
-sulfamic acid is a far better choice, but better yet, is small controlled doses of nitric acid. Only adding more when the previous addition is used up.

Precipitating in a flask isnt the best, a beaker is (or open top bucket), so you can rinse and wash the gold in the beaker itself, increasing its purity.
Putting it in a filter and burning it off is also a bad idea, as smoke can carry up the small bits of gold when its ashing off.

...not to nit pick... But, if you are posting up your video in 3 different spots, it should be really good (and accurate)


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## Shark (Jul 13, 2017)

> ...not to nit pick... But, if you are posting up your video in 3 different spots, it should be really good (and accurate)



...and in the advertising section as well.....


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