# Filtering Problems. Gold powder all over the place.



## skyline27 (Sep 27, 2007)

I dissolved 6 grams of foils in muriatic and clorox. Everything was good until I tried to filter it. I used three standard coffee filters. A portion of the gold was captured in the filters (2 grams). The rest is running through the filters, impregnetaed in the filters, on the strainer. Is there a better way to capture the gold or make it clump together before filtering?


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## lazersteve (Sep 27, 2007)

Skyline,

*Once the gold is dropped with SMB it should never leave the beaker until it is cleaned and dried*. The final steps before dumping the gold powder into the prepared melting dish or a filter to transfer it to the dish are the washing and drying stages. 

Here's a step-by-step after the gold is dropped:


Let the gold settle.
Test the clear or slightly colored solution to see if any gold remains dissolved (use stannous chloride)
Add more SMB if the solution test positive.
Repeat above unitl negative test results.
Let settle completely.
Pour or Siphon off the barren solution into the stock pot.
Wash the powder with 3-5 rinses of hot water. (Add water to beaker with gold and heat until near boiling for 3-5 minutes)
Pour or siphon off water.
Wash the powder with 3-5 rinses of hot HCl.
(Add HCl to beaker with gold and heat until near boiling for 3-5 minutes)
Pour or siphon off HCl.
Wash the powder with 3-5 rinses of hot water. (Add water to beaker with gold and heat until near boiling for 3-5 minutes)
Pour or siphon off water
Wash the powder with 1-2 rinses of hot Ammonium Hydroxide if silver was present in source material.
(Add ammonium hydroxide to beaker with gold and heat until near boiling for 3-5 minutes)
Pour or siphon off ammonium hydroxide. (DO NOT add the ammonium hydroxide rinses to the acid rinses!)
Wash the powder with 3-5 rinses of hot water. (Add water to beaker with gold and heat until near boiling for 3-5 minutes)
Pour or siphon off water
With only the now clean gold powder (and very little water) in the same beaker which it was dropped, begin heating over low heat.
Swirl the gold powder around the low heat until the gold clumps up and forms nice globs that stick together. 
Continue heating until any acid vapors are gone.
Dump clean dry gold into prepared melting dish, glass jar for storage, or a few filters to transfer to dish or jar later.

Thank Harold for this fine tuned method of washing and drying. It results in very clean gold that clumps together well and melts like butter. The entire process takes about thirty to forty-five minutes, but is well worth the extra care when you see the butter yellow gold it produces.

As for your mishap try this:

Collect the 2 grams of the gold you can salvage and put it some place safe.

Mix up some HCl-Cl in a separate beaker and quickly add it to the filter holding all your gold. Keep cycling the solution thru the dirty filter until the lost gold is all absorbed into the HCl-Cl. Now treat the pregnant solution with SMB and follow the steps outlined above. You'll find you have not lost anything if you do this right. If any of the powder went thru the filters be sure to collect it as instructed in the opening steps above as well.

Keep us posted on your progress.

Steve


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## skyline27 (Sep 27, 2007)

Thank you for the concise instructions. One more question on this issue. When siphoning/pouring off the barren liquid, how do you deal with the floating gold particles?


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## Harold_V (Sep 27, 2007)

skyline27 said:


> Thank you for the concise instructions. One more question on this issue. When siphoning/pouring off the barren liquid, how do you deal with the floating gold particles?



If you'd get in the habit of incinerating your metals, and washing your lab ware *very well * (using soap and water, rubbing with a sponge) before use, there would be NO floating gold. 

If you find you have some, try shooting it down with a wash bottle. If your solution is contaminated with traces of oil, that may not work. 

Harold


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## lazersteve (Sep 27, 2007)

I just give the solution a few sprays with my spray bottle and let them settle with the rest of the gold. If you have a lot of floaters the gold may need to be reprocessed one more time after cleaning. Good clean gold drops quickly and completely, forming a nice clump in the botom of the beaker. If you turn your beaker with the solution in it to the side and the gold doesn't all slide to one side you most likely need to clean it and redissolve it again to increase the purity. As Harold has stated good clean gold agglomerates together very readily.

Steve


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## Never_Evil (Sep 28, 2007)

Just as an additional note, do not use a plastic container to drop your gold from. Ive experience a slight setback where the plastic is capturing the gold dust particles. Use a glass container that way all gold can be recovered. If you did use plastic, HCL-CL can be used to reclaim the dust and redrop with the SMB. Hope this step helps others too.


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## skyline27 (Oct 1, 2007)

To clean up the gold laden filters, could I fill a spray bottle with the muriatic and bleach mixture and spray it through the filters?


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## lazersteve (Oct 2, 2007)

Skyline,

Don't spray acids and bleach on the filters, you'll end up with a huge cloud of chlorine which could be very harmful. Just mix up a small amount and pour it thru the filters repeatedly until the gold is absorbed.

Steve


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