First and foremost, you DO NOT put soil/rocks in Acids if you do not have an assay.Hello to the professors and hardworking people of this website. Please can anyone help me. I dissolved gold sulphide soil in aqua regia and precipitated gold with zinc powder along with some impurities.I roasted the sediment at 600 degrees, then I put it in nitric acid. The brown sediment remained at the bottom, and I melted it with air gas.I only used borax, when it was semi-solid, it formed a piece of yellow metal at a temperature of approximately 600-700 degrees, but when the temperature reached 1000 degrees, the moment it became liquid, its volume became smaller and smaller and the yellow glow disappeared, brown slag was formed and melted failed.Now, where was my mistake that I could not succeed? Was there an impurity deposit, or did I not use a good melting fluxes, or was it not gold?Sorry it took so long
Next, roasting is the first you do with Sulfides, this drives off the Sulfur.
Did you test your AR for Gold?
No point in roasting after dropping with Zinc, why did you not use Copper?
Zinc drops all metals, but Copper drops only precious metals and Mercury.
Pleas describe in more detail what you have done.
Step by step please.