My yield

[overneo]

pins, two times HCL + H2o2 + boiled tap water.

Next + wash with HCL / tap water / ammonia.

[img:1600:1200]http://over93.free.fr/y.JPG[/img]

 

[overneo]

question : how to remove and recover the powder from the filter properly?

 

[Anonymous]

This looks like you've dissolved and dropped the foils,but you didn't mention it in your process.If that is the case you're going to have to do it again and use a better filter system(too many contaminants in your powder).Several coffee filters will work fine.Put the entire thing(filter and all)in HCl/Cl disolve the powder then filter out the contaminants(and the old filter making sure you rinse all of the AuCl out of the old filter and contaminants).Let it sit a few hours then drop the gold again.After that you'll need to do a few acid washes,keep washing until the resulting acid is perfectly clear(no cloudiness or discoloration).2 or 3 should be enough since this will be your second precipitation.Then drain and run 3 -4 water washes.Each time make sure you let it sit long enough for ALL of the powder to settle.Then do your melting.If in fact the picture is exactly what you extracted from the solution without dissolving and dropping the powder then you have a whole new set of problems.Steve or harold could maybe help you from here.
Johnny

 

[overneo]

thanks for your help

 

[meng2k7]

question : how to remove and recover the powder from the filter properly?

use a spray bottle, put it in a clean beaker then do "hcl-clorox", then drop the gold with smb.

i hope it will help.

 

[Smitty]

Dry the filter, then incinerate the filter with low flame, do not melt the gold and other metals together. Put all ash into a glass container and cook it with 1 part nitric acid and 3 parts water. Poor out the liquid and repeat the wash until liquid is clear. It would be a good indication that most of the base metals are out. Dry out the material left over then use use HCl+Clorox to dissove the gold. When you go pour the AuCl into the filter it will catch all of the solid waste in the solution. Precipitate and wash like normal. You might even dissolve and re-precipitate one more time before making your nugget.

Good luck