Preparing for Christmas

[Martijn]

I have precipitated all the gold from this batch with copper powder and I want to know if there is any copper left in the gold powder and find out how well i did.
It's about 70 grams now after processing the wash solutions.
So back in the AR for a second refine.
A fresh 1.5kg SMB just came in so I have a solution ready to make beautiful lightbrown gold dust.

I used up most of my homemade HCl so back to making some more.
The 300ml i have left might not be enough for AR and washing the powder.

New destillation setup without the refill flask and the hose to the beaker now has a bigger raise in it making the fumes partially condense in the hose and run back in the small flask.
This is probably a concentrated HCl, looking at the color. I'll add that to the beaker after every run.
I captured the chlorine waterfall under the inverted funnel on video. Cool to watch it fall down.
I love watching chemistry in action!


Gold dust waiting for a new warm bath

I'll try to keep nitric use as low as I can to see how much is needed for fine powder processing it slowly.

 

[eaglekeeper]

I captured the chlorine waterfall under the inverted funnel on video. Cool to watch it fall down.

I've never made HCL, but I'm wondering if using a gas dispersion tube would more efficient instead of the inverted funnel.... or a combination of both.

 

[Martijn]

I've never made HCL, but I'm wondering if using a gas dispersion tube would more efficient instead of the inverted funnel.... or a combination of both.

I have not tried the tube, but once the air is up to temperature and the chlorine is released there are no bubbles coming from the funnel. All the gas is absorbed by the water.
I think it's the large surface that makes this possible.
It sure is cool to watch it fall down in a stream.
I can imagine bubbles escaping mean loss of gas.
Until you hit the azeotrope of 20% no chlorine gas escapes the solution. It al falls right to the bottom like I filmed. And i tested with bottle of ammonia in the fume hood. No white smoke over the open beaker.
Once less chlorine is produced, the temperature rises and heats more glassware, until the 31%HCl (I tritated it) in the small flask started boiling at around 50C . Turned it off at that point and captured the small flask acid in a separate bottle. 250ml of it after a couple runs. That will be used for washing the gold powder.

The big 1.5 liter beaker had 16.5% in it just before it turned it off. I added the last 50 ml from the small flask to the beaker.

My 67gr gold powder has dissolved in 450ml of the 16% HCl and 15ml of the 68% homemade nitric. There is some grayish light stuff leftover. Maybe some Pt dust that did not dissolve and some silver chloride
So i'm hoping a really low nitric use or i have way less gold than I thought.
The solution is a beatiful deep red.
To be continued...