Problem with processing polishing waste

[adoreman]

Hi fellow refiners,
I have used polishing waste from my jewelry factory. I usually use the" RED " polishing compound to process my polishing for my jewelry. What i do with all the waste is i burn it thoroughly. I then run it through a sieve and get all of the small dust particles.

I mix 2 kilos of this burnt polishing dust and mix 25% litharge and 8kg of borax.
I mix this thoroughly and melt it to get my recovery.
I usually do not have any problem with this and i am able to recover my gold..

However, i have recently used "GREEN POLISHING COMPOUND" and i have done the exact same mix as i do when i used red polishing compound. However i had a provlem with the mix and i was not able to get any recovery of my gold. I was only able to get 1 gram or less.

Does anyone know what i should do to be able to recover my waste when i used green polishing compound? What is the difference with the chemical components of the red compound and the green compound and why i am not able to recover from the green?

I have done some research and found something relating to agua regia, however i do not have the facilities to use agua regia..

Any welp will be much appreciated. Thank you very much

 

[butcher]

There are many types of buffing compounds, silica, alunmia, garnet, rubies, zirconia, boron nitride silicon carbide, magnetite, hemitite, and other iron oxides, this list can go on, these are basically a grit material in a wax binder.

Red rouge is iron oxide.
Green rouge (funny they call it rouge I always thought rouge meant red) is chrome oxide.
chrome oxide and iron rust react differently to the acids.

Basically many of the buffing or sanding compounds can be made from ore or metals oxides, and just like in leaching gold from ore the ore or the buffing compounds can act differently with acids, and although the gold will not be chemically bound into the buffing compounds matrix like gold in ore, the metals or chemical compounds can effect the leach, or the way you may have to go about the leaching process.

I am not a jeweler, so I am not that sure if they make other green buffing compounds besides chrome oxide, also as far as I understand chromium compounds are very dangerous to burn, you will need more help, or study on the safety portion of this than I could give you.

From what I gather your melting with a flux for recovery, I would look at incineration and leaching process, Harold has made several very detailed and informative posts on how he processed polishing sweeps, I would study those posts, maybe Harold or or another member with more knowledge can also add more help into this thread.

 

[adoreman]

There are many types of buffing compounds, silica, alunmia, garnet, rubies, zirconia, boron nitride silicon carbide, magnetite, hemitite, and other iron oxides, this list can go on, these are basically a grit material in a wax binder.

Red rouge is iron oxide.
Green rouge (funny they call it rouge I always thought rouge meant red) is chrome oxide.
chrome oxide and iron rust react differently to the acids.

Basically many of the buffing or sanding compounds can be made from ore or metals oxides, and just like in leaching gold from ore the ore or the buffing compounds can act differently with acids, and although the gold will not be chemically bound into the buffing compounds matrix like gold in ore, the metals or chemical compounds can effect the leach, or the way you may have to go about the leaching process.

I am not a jeweler, so I am not that sure if they make other green buffing compounds besides chrome oxide, also as far as I understand chromium compounds are very dangerous to burn, you will need more help, or study on the safety portion of this than I could give you.

From what I gather your melting with a flux for recovery, I would look at incineration and leaching process, Harold has made several very detailed and informative posts on how he processed polishing sweeps, I would study those posts, maybe Harold or or another member with more knowledge can also add more help into this thread.

Hi butcher,
Thank you very much for your extensive knowledge and the information on the green compound i am using. I will do more research on how i can process this with chemicals or AR. I was able to burn the material with no problem tho.
Thank you

 

[adoreman]

Oh and yes. Funny thing they call it green rouge hehe

 

[nickvc]

There are two ways I know of that recover the values from polishings, the one I have used very often the other is for those ith the correct safety equipment. The old method is to incinerate the polishings crush them, sieve them and then mix with lead which acts as a collector and feed them into a crucible and into a furnace at low temperature at first so the lead melts and acts as a collector, this is allowed to cook for several hours and the resulting melt is poured into a mould. This is then placed back into the furnace at high temperature to oxidise the lead and leave a button containing the values, this process is extremely hazardous to anyones health without the correct extraction and environmental controls so is used mainly by the large refiners or was in the past. The method I used is exactly the same as Harold's, again incineration and sieving and removal of any magnetics and depending on the suspected values either boiling in nitric to remove silver if sufficient is present or a goid boil in hydrochloric to remove as much base metal as possible before again boiling in AR. If done correctly the first leach will remove 90% of the values so a second leach is required but if you recover more than 10% in the second leach by a large margin a third leach maybe required. The term boiling dissolving values is normally frowned on but with sweeps it helps to stop hot spots and cracking your beakers and keep the acids penetrating the powders to leach the values, a fume hood and srubber is advised for this process as some values will be vaporised but can be recovered later.
By simple melting and fluxing of jewellery sweeps I suspect values will still be contained in the slags from the resulting bars which because of the volumes can be difficult to efficiently recover.

 

[goldsilverpro]

If you follow the Harold_V method to a tee, you will have success. He's the one you want to listen to on this subject. After reading the 1st post on the 1st link below, read the entire thread. Then wade thorough his posts in the 2nd link.

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=1253&hilit=polishing+waste&start=20

http://www.goldrefiningforum.com/phpBB3/search.php?keywords=polishing+wastes&terms=all&author=harold_v&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

 

[adoreman]

There are two ways I know of that recover the values from polishings, the one I have used very often the other is for those ith the correct safety equipment. The old method is to incinerate the polishings crush them, sieve them and then mix with lead which acts as a collector and feed them into a crucible and into a furnace at low temperature at first so the lead melts and acts as a collector, this is allowed to cook for several hours and the resulting melt is poured into a mould. This is then placed back into the furnace at high temperature to oxidise the lead and leave a button containing the values, this process is extremely hazardous to anyones health without the correct extraction and environmental controls so is used mainly by the large refiners or was in the past. The method I used is exactly the same as Harold's, again incineration and sieving and removal of any magnetics and depending on the suspected values either boiling in nitric to remove silver if sufficient is present or a goid boil in hydrochloric to remove as much base metal as possible before again boiling in AR. If done correctly the first leach will remove 90% of the values so a second leach is required but if you recover more than 10% in the second leach by a large margin a third leach maybe required. The term boiling dissolving values is normally frowned on but with sweeps it helps to stop hot spots and cracking your beakers and keep the acids penetrating the powders to leach the values, a fume hood and srubber is advised for this process as some values will be vaporised but can be recovered later.
By simple melting and fluxing of jewellery sweeps I suspect values will still be contained in the slags from the resulting bars which because of the volumes can be difficult to efficiently recover.

Thank you for that nick. That is the exact same thing that i did with my sample, i used the old method of incinerating it then using lead. Then when i oxidized the impurities and lead afterwaerds, i was left with almost nothing:/.. I will do the process of agua regia today nick. I will try to do the agua regia and hydrochloric and i will update u guys on the rrsult. Thank you also mr goldsilverpro. I will read on that link u sent now. Much appreciated

 

[rusty]

There are two ways I know of that recover the values from polishings, the one I have used very often the other is for those ith the correct safety equipment. The old method is to incinerate the polishings crush them, sieve them and then mix with lead which acts as a collector and feed them into a crucible and into a furnace at low temperature at first so the lead melts and acts as a collector, this is allowed to cook for several hours and the resulting melt is poured into a mould. This is then placed back into the furnace at high temperature to oxidise the lead and leave a button containing the values, this process is extremely hazardous to anyones health without the correct extraction and environmental controls so is used mainly by the large refiners or was in the past. The method I used is exactly the same as Harold's, again incineration and sieving and removal of any magnetics and depending on the suspected values either boiling in nitric to remove silver if sufficient is present or a goid boil in hydrochloric to remove as much base metal as possible before again boiling in AR. If done correctly the first leach will remove 90% of the values so a second leach is required but if you recover more than 10% in the second leach by a large margin a third leach maybe required. The term boiling dissolving values is normally frowned on but with sweeps it helps to stop hot spots and cracking your beakers and keep the acids penetrating the powders to leach the values, a fume hood and srubber is advised for this process as some values will be vaporised but can be recovered later.
By simple melting and fluxing of jewellery sweeps I suspect values will still be contained in the slags from the resulting bars which because of the volumes can be difficult to efficiently recover.

Thank you for that nick. That is the exact same thing that i did with my sample, i used the old method of incinerating it then using lead. Then when i oxidized the impurities and lead afterwaerds, i was left with almost nothing:/.. I will do the process of agua regia today nick. I will try to do the agua regia and hydrochloric and i will update u guys on the rrsult. Thank you also mr goldsilverpro. I will read on that link u sent now. Much appreciated

 

[adoreman]

Thanks for that rusty. I will read on that file you quoted.