Pure Gold Refined From Jewelry And Dental Scrap

Very nice. You should consider prepping your nugget in the final step by dropping the molten metal into a beaker of water. This will give a "natural" porosity to the nugget that looks really nice. It may even purify it slightly as it any remaining water solubles may stay in the beaker. A little dangerous handling the molten metal, but then the whole thing is dangerous to begin with. I'd never do this at home.

I actually consider this process to be pretty safe. I set up on my back porch which is covered but open on three sides. Fumes of chlorine and nitrogen dioxide generated during the process were quickly dispersed and no extra ventilation was needed. I'm not concerned about minor contact with bleach or swimming-pool-grade HCl, and sodium nitrite is practically non-toxic. The biggest hazard I faced was getting impatient about picking up the gold nuggets before they were cooled; I might have singed a finger!

Great work.
You'll have to change your handle to "Walter White"!

Final report on this thread:
I took my brick to our local coin shop where they have an XRF machine used to measure precious metal content of jewelry and other items they buy from the public. The brick tested at 24 karat / 99.99 gold which is the highest purity the device can measure.

As I shaped my brick the edges became thin and sharp. I used my torch to touch up the edges, heating the brick just enough so those edges would liquefy and become rounded. A glowing gold brick is a lovely thing!

Sure is
I like your process