# Need help with polishing dust and buff refining



## willirolex (Aug 12, 2017)

Hi I have a question about polishing dust and buff refining. I haven't started any polishing dust and buff refining before so this will be my first time. So before I do that I want to know how is the best way to incinerate the buffs and the dust? is it okay to just burn it in a gas stove with a stainless steel pot? and then after it is burned and turned into ashes, i should sieve it right? after that can i just melt it down? cause someone told me that the polishing compound might get in a way during the melting process. If it is possible to melt it, can I just do the inquartation process to refine it?? 

Thanks before


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## jimdoc (Aug 12, 2017)

Please don't double post, someone will answer you when they can.
This second thread will disappear when a moderator sees it.


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## FrugalRefiner (Aug 12, 2017)

Actually, I deleted the other post as this one is in the appropriate section.

Dave


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## jimdoc (Aug 12, 2017)

FrugalRefiner said:


> Actually, I deleted the other post as this one is in the appropriate section.
> Dave



Smart, I was thinking that too after I posted. Thanks.


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## 4metals (Aug 12, 2017)

I also received a PM with the same request, linking this thread. I would prefer not to spend time typing for the benefit of 1 member if we think that a thread that will be helpful to many can evolve. 

So why don't we provide the answers here for all to see and comment on?

First before we can give any practical answers we need to know the quantity of sweeps Willirolex has to process as this will affect the answer. So if Willirolex can please answer the question we can start.


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## willirolex (Aug 13, 2017)

Hi, so sorry with my inapropriate manner of mine. I am not sure on how much polish sweeps that I will be dealing with. But I calculate all the loss of gold from the polishing process and it will be around 500 grams of 9k gold. So would you suggest for me to first measure the total weight of the polishing sweeps and the buffs?


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## nickvc (Aug 13, 2017)

I will assume when you say buffing dust that it is from carborundum wheels or buff sticks, this can be melted but incineration first would be a good idea, the next step is preparing the necessary flux followed by a long soak at high heat in a furnace, occasional stirring would also be beneficial, if done correctly you should recover 90-95% of the gold, in honesty wet refining would probably get a better return, once incinerated place into a beaker add distilled water, heat and add slow additions of nitric, this needs doing slowly until no reaction is visible, no fumes or bubbling in the solution, cool , filter and rinse well with distilled water, this should remove most of the silver and base metals, then return the remaining powders to the beaker add plenty of Hcl and heat then again slow additions of nitric, the gold should all be dissolved when after the last addition of nitric it produces no reaction but always add a little more Hcl and watch for reactions, cool and filter the solution and precipitate the gold with the method of your choice.
The silver can be cemented from the solution using copper
Be aware all dissolutions produce toxic fumes so they should be done using a fume hood.
Polishing dust needs incineration and is best recovered again using acids, the difference is that to make filtering easier you treat the powders with Hcl and then use AR, if you have volumes you need to boil the solution, use a watch glass and stir regularly to avoid hot spots and broken beakers, I'd suggest at least 6 hours on the heat.
Filter the solution once cool and use water washes to remove as much solution as possible, if done correctly you should recover 90% of the gold the first time, you need to decide if it's worth treating the powders again, as this is a first time processing this material I'd suggest a second treatment.


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## 4metals (Aug 13, 2017)

The reason I asked for the quantity of material you are starting with is because different quantities of material require different methods of incineration. If you are a small jeweler and can collect your polishing sweeps and buffs in smaller batches comprising a few kilograms before burning you will need a cast iron pan and a torch to burn the sweeps to produce the ash. If you are talking about drums of the material it is best to use a larger incinerator to produce the ash. 

No matter which approach you use to process this material they must be burned before they are processed further. 

Some small refining operations do successfully flux and melt their sweeps but the fluxing is largely dependant on what is in the sweeps and it is a process with a rather long learning curve. But if you have the time and the proper furnace, melting is an option if you can control what is in the sweeps you process. This is usually only practical when you process sweeps and buffs you generated in your own shop. The materials that are mixed into drums with material shipped as sweeps to refineries makes the melting process much more complicated and as a result, hit or miss.

This is why acid refining is preferred by small operators looking to recover the values from their material, which is why Nick wisely has suggested it as your best option. 

If you have burned the sweeps properly, the polishing compounds which are usually a waxy base are burned off and the resultant powder is crushed and sifted. Usually through a screen with a 40 mesh screen. This will produce a -40 mesh powder, where most of your gold will be, and the oversize that doesn't pass through the screen which can be separated with a magnet to remove any magnetic pieces, and the balance can be melted into a button or small bar for further refining. 

What, if anything have you done to your polishing dust and buffs thus far? I am not sure what type of buffs you use in Indonesia but here in the US they either have a wooden hub on the wheel with a threaded center, or a lead hub which you drive a pointed thread into to attach it to the wheel. In either case, you want to remove these center hubs from the wheels. If they are steel they can be removed by a magnet after burning but if they are lead, it is best to get them out before you incinerate because lead in your sweeps will find its way into your refined silver so you want to minimize that up front.


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