# Filtering the gold dust



## Smitty (Nov 29, 2007)

I'm having doubts about my filtering skills. What I did was use AP to seperate the metal from the gold. Then I filtered the the gold and cleaned it up with some HCl. I then added peroxide to the gold HCl solution and left it there overnight. Well the gold went into the solution like Steve said it would. It was great, something actually worked as expected. Yes, I'm a newbie at this. I then added SMB into the Auric Chloride that I have finally created and precipitated the gold into black dirt. This is where my doubts begin. From what I'm reading I should let it settle in the solution and poor out the remaining liquid trying to leave what I have at the bottom as best as possible. Then wet 3 coffee filters and pour the dust into the filter and leave it to dry in the filter before fluxing and melting. Well the liquid in the cup after I poured the dust into the filter is grey, so I let it settle again and attempted to filter it thinking it might be gold that did not make the filter. I now use 4 filters pre-wet to catch this leftover, but there is nothing in the filter and the liquid again is grey like before. Is that a loss I have to put up with or is there another way to recover the very fine dust? thnx all. 

I also need some good ideas on how to melt the gold if I am not able to get an O2+acetylene torch. Would a MAPP gas hand torch from Lowes ok?


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## Never_Evil (Nov 29, 2007)

You almost got it.

After the initial AP bath, wash the remaining gold a few times with HCL, then with water. Only when the water wash is clear in color should you move onto the next step. As far as pouring...dont do it anymore. Go to a local hardware store and get some clear vinyl tubing (1/8 or 3/16) The smaller the tube the slower the syphoning goes, but gives you a better chance to react to any particles floating around. Dont pour/syphon any of the gold into the filter the first time if at all possible, this filter step is used to catch the small small gold for later reclaiming. In Steve's video, he uses a plastic spoon to scoop out the gold mash. From this point rather than doing a second round of AP, you need to use HCL and Chlorox. *THIS PRODUCES NASTY POISONOUS FUMES* but it will properly produce the auric chloride as intended. After all the gold foils are gone, use your glass rod to stir around the salt and debris to make sure you have all the gold dissolved into the solution. This filter step you pour everything through the filter then double the total volume with water. Precipitate out with your smb. After all the gold settles, again syphon off all liquid as possible without losing any powder. When you get to the end when there is almost no liquid, use your spatula to get all your gold out and put it on a filter.

Yes a MAPP/oxy gas torch will work. With the smaller tip on that torch, you need to be careful you dont blow out any of the gold. Work slow and you should produce a nice button. Im on the torch step now.

Good luck, if I misinterpretted anything from Hoke's book and/or Steve's videos, please chime in and make sure we have it all correct so there are no big errors.

Dennis


:lol: Go Pack Go :lol: (for tonights football game)


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## lazersteve (Nov 29, 2007)

Daniel is right on track, heres a little extra.

Gold Powder Cleanup

The precipitated gold powder should be brown and never leaves the vessel it is dropped in until it is dry. From there it goes into a properly prepared melting dish.

I would redissolve the powder you currently have in the filter with HCl-Cl and reprecipitate with SMB. It should separate very well from the solution. 

The gray liquid should be tested for dissolved gold with stannous chloride.

If the gray liquid has suspended gold it will redissolve by the addition of HCl-Cl. Evaporate the liquid until concentrated and then add SMB. Collect the brown powder. The gray may just be contaminates.

Steve


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## Smitty (Dec 2, 2007)

thanks for the link Steve. I remember reading that somewhere in these pages.


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## Smitty (Dec 3, 2007)

Never_evil said MAPP/Oxy torch works and I beleive him, but what I was wondering is about the MAPP gas torch used for brazing and copper pipe soldering that has no attachment for oxygen tank.


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## jimdoc (Dec 3, 2007)

Smitty,
The mapp torch will work on gold, but
not the pgm's without oxygen. 
Jim


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## Smitty (Dec 10, 2007)

Cool thnx Jim.


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