# HOW TO REFINE THE JEWELERS POLISHING DUST



## primogem (Nov 18, 2011)

hi, i burnout the polishing dust up to 1350f, and the remain content is checked by xrf-analyser as followings,

au 35.7% ag 9.3%
pd 2.5% pt 1.0% rh 0.1%
cu 7.0% zn 1.2% ni 0.7% fe 42.5%

want to get any recommendable refining method.

for the test experiment, i mixed with borax5 vs ash 7, and tried to meltdown up to high 1,200 c, but the result is not good. possible oxidized more.

how about the following thinking. ist soak with hcl 32% for a long hours,
and thwn do filtering the solid. finally treat with aqua-regia.

appreciate your kind recommendations, if any 

best regards


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## jimdoc (Nov 18, 2011)

All capital letters is considered shouting, as well as annoying to read.
If you edit out the all-caps you will probably get answers to your questions, as some members may just ignore you because of the caps.

Thanks. Jim


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## jimmydolittle (Nov 18, 2011)

First of all, your post is difficult to read. It’s considered yelling when you use all caps. I will recommend you stop and read Hoke’s book. Several members have a link where you can download it. Chapter 11 in her book is dedicated to sweeps and filings.http://www.scribd.com/doc/2815953/Refining-Precious-Metal-Wastes-C-M-Hoke

On second thought, she talks about using cyanide in that chapter. I would not want you to kill yourself, or anyone else. Please do read her book.

Search the forum, there are 63 posts, dealing with sweeps.


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## nickvc (Nov 19, 2011)

Primogem welcome to the forum.
Number 1 I wouldn't trust an xrf reading on any powder sample as it scans the surface and very likely will not give an accurate result.
You can melt sweeps with the right mixes of fluxes and a good hot and long time in a furnace but always check your fluxes.
If you now are going to try to refine your sweeps the first job is to remove any magnetics from it, run a magnet over it and set aside, don't discard, any thing that comes off. Then as you suggest a good hot soak in hydrochloric with plenty of stirring or even a light boiling one of the few times this phrase has any place in refining. Once cool filter and wash through with a water rinse and then proceed with AR adding plenty of hydrochloric and small additions of nitric,again plenty of stirring or a light boil will help to expose all the material to the acids,cover with a watch glass if you do boil, allow to cook for 4-6 hours. Allow the solution to go cold and filter and then use precipitant of choice to recover your gold, it will almost certainly need re refining to achieve good purity. If you recover say 200 grams you will have approximately 20 grams left in the sweeps so a second treatment may be required to achieve a good recovery. The solutions from your gold recovery will have your Pt and Pd in it so for this you can now use your magnetics as the start for your stock pot and recover any values in them and cement any values out of the solutions. Your silver I'm afraid will be trapped as chloride in your sweeps with traces of other values but again dry and keep until you have a decent volume and send it out for recovery of the values to a large refinery.


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## primogem (Nov 19, 2011)

mr nickvc, thanks for your kind recommendations in details. 
aa) understand that i need to do magnetic throughly before further process ,and need to get metal samples for accurate xrf reading.
bb) as i mentioned i mixed borax 5 : ash 7, and heated with oxygen/propane gas tourch for about five minutes only. but the result is not so good. 
---could not heat-up for long hours, and assume the flux is not so fluid??
in this regards please let me know what kind of flux and how much flux is recommendable in this case. 
melting furnace using graphite crucible ( max temperature :1100c) is recommendable for the temperature and the long hours heating ??
cc) cook for 4-6 hours means total required period including light boiling and stirring.?? electro-magnetic- heater/stirring equipment is recommendable??
dd) for the Pt and Pd recovery from the solutions, you mentioned that can use my magnetics. please explain more in drtails how i can use my magnetics.
ee) for the magnetics and the residue from AR treatment. --- you means we need to use big refinery ??


nickvc said:


> Primogem welcome to the forum.
> Number 1 I wouldn't trust an xrf reading on any powder sample as it scans the surface and very likely will not give an accurate result.
> You can melt sweeps with the right mixes of fluxes and a good hot and long time in a furnace but always check your fluxes.
> If you now are going to try to refine your sweeps the first job is to remove any magnetics from it, run a magnet over it and set aside, don't discard, any thing that comes off. Then as you suggest a good hot soak in hydrochloric with plenty of stirring or even a light boiling one of the few times this phrase has any place in refining. Once cool filter and wash through with a water rinse and then proceed with AR adding plenty of hydrochloric and small additions of nitric,again plenty of stirring or a light boil will help to expose all the material to the acids,cover with a watch glass if you do boil, allow to cook for 4-6 hours. Allow the solution to go cold and filter and then use precipitant of choice to recover your gold, it will almost certainly need re refining to achieve good purity. If you recover say 200 grams you will have approximately 20 grams left in the sweeps so a second treatment may be required to achieve a good recovery. The solutions from your gold recovery will have your Pt and Pd in it so for this you can now use your magnetics as the start for your stock pot and recover any values in them and cement any values out of the solutions. Your silver I'm afraid will be trapped as chloride in your sweeps with traces of other values but again dry and keep until you have a decent volume and send it out for recovery of the values to a large refinery.


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## jimmydolittle (Nov 19, 2011)

for the Pt and Pd recovery from the solutions, you mentioned that can use my magnetics. please explain more in drtails how i can use my magnetics.

Pt. and pd. are non magnetic. Take a strong magnet and place it in a baggie. Run it through the sweeps, to pick up the magnetic material. Off to the side, pull the magnet away from the baggy. continue to do this until no more iron filings are present in the sweeps.

you means we need to use big refinery ?? No you do not need a big refinery.


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