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Well I have to say this processing black sand is not as easy as it looks on YouTube
To start with I took another look at my retort after thinking about how my coolant got hot.
I made a mistake in the original build by welding the heating chamber onto the coolant tank.
So I cut the heating chamber off and extended the condensation tube to reach clear of the tank.
This is our first attempt at extracting the gold from our black sand so I started by measuring out 200g of sand and put it into the little tumbler with the shiny little balls and a spoon of caustic soda.
When I placed it on the tumbler it suffered from wheel spin so I had to stretch a rubber glove over the bottle to give it traction.
I gave it a good tumble for a couple of hours before washing out the muddy water and caustic soda. Then I measured out 25g of mercury and put that into the tumbler with the cleaned sand and the balls and gave it another hour of tumbling.
We tipped it into the pan and got a bit of a surprise. We had no liquid mercury, only amalgam.
Does that mean 25g of mercury was not enough?
I picked the amalgam out of the pan and put it into a cloth. We don't wash cars here so no chamois
Then I twisted the cloth until it broke through but didn't extract any mercury?
There was nothing else I could do so it went into the retort. I placed a little plastic lid into the pan to catch the mercury because I want to know how much we recovered.
The gold taken from the retort was an ugly looking thing :|
Then I put it into a little crucible and applied the heat from the oxy/LPG torch.
The gold looked good when it was flowing about molten but when it cooled it came out all wrinkled. I tried again but the result was the same so I called an old prospector with many years of experience. He told me to pop over and we'd sort it out. Well that didn't work because the same thing happened for him and his opinion was that the gold is contaminated with something.
From there I drove to another prospecting friend, the guy who talked me into building a dryblower. He gave it a go for the same result and also thought it was contaminated. However, he persisted, swapping the gold from my crucible into one of his own then he added more borax and in the end poured it back into my crucible to bring it home. While it was still molten he poured off the excess borax flux and as it cooled it looked better.
He said to throw it into a tub of water and the button will pop out, well it didn't
I ended up smashing the crucible to extract our little 44.8g gold button. It was a battle but it worked out in the end with a surprise result from our first 200g of sand processed
