Hi!
This is part 4 of the gold recovery and refining from the 5kg Intel 386 and 486 ceramic CPUs
videos.
I'll be washing and melting the gold powder which was left to settle in the previous video.
First, I had to check with stannous chloride if there is still gold in solution.
Negative!
I've decanted the barren liquid and collected the powder in a small beaker.
After settling I've added boiling water and placed the beaker on a hotplate.
Boiling for 5 minutes.
Water is replaced with concentrated hydrochloric acid.
Boiling for another five minutes.
the acid washes are collected in a separate flask, as they may contain a small amount
of gold.
Another portion of fresh concentrated hydrochloric acid is added and boiled for 10 minutes.
Hydrochloric acid washing is repeated until the acid becomes colourless.
The acid is replaced with water which is boiled for 5 minutes and then decanted.
The boiling water wash is repeated 4 times, 5 minutes each.
After washing, the powder is moved to the melting dish.
This is the last powder washed in the same manner.
Combined with the rest of the gold.
Lets melt it!
But first a pinch of borax.
Another pinch of borax!
Ooops!
I've scratched it!
Boiling in diluted hydrochloric to remove the borax.
Nice and shiny!
I think I can skip the refining step.
25.2g of pure gold from 4960g of ceramics.
In the next video I will process the ceramics with aqua regia one more time, and will scavenge
the washing waters for any remaining gold.
And in the final part, I will process the lids.
Thanks for watching!
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