Near a river you say. You (may) have sand containing placer gold.
Are you paying for bags of tailings or concentrates or just sand dug up and you're concentrating it? Not quite clear to me.
That assay report is from sept. 2019, describing crushed ore... now is it sand or crushed ore? Ore comes from hard rock mining, placer gold sand is classified, washed and concentrated.
Did you pay for this assay, and why wait three years before processing this ore?
Are you sure he's your friend? Friends are not always the best buisiness partners.
Sounds to me he once got a good assay and now uses that to sell river sand with magnetic black sands.
Anyway, i believe your possible gold containing sand was concentrated in the ground by river gravity separation in stead of hard rock, so It can be washed back out again.
No need for chemistry imo.
Classify better to comparable particle size and you can separate it all better.
Separate iron from gold with a magnet under water, preferably where the gold line on the shaker table starts and repeat several times on both concentrate and magnetic tailings to get a better separation each time. You will drag some gold out with the iron. So redo that a couple of times to purify the gold. Put the magnet in a bag to get the iron off easily.
Once you have clean gold concentrate, just melt into a ingot and sell it with a bit of impurities. The buyer will scan the purity and pay you accordingly.
Do you have a picture of the concentrates you processed with AR?
Why do you want to refine it further?
Assuming you've at least watched the safety lesson and have improved your safety standard:
To test for pm's with AR, dissolve a bit of the concentrate from the bottom in a test tube.
Add a bit of concentrate to a test tube, cover it in HCl and add one drop of nitric.
To speed the reaction up safely, you could au-bain-marie the test tube in hot water.
Add HNO3 one drop at a time until no more reaction is happening, so there are no more tiny bubbles forming upon addition of one drop of HNO3.
If you had to add relatively much HNO3, the reaction could be stopping because of low HCl level, adding two drops of HCL will show that.
When the reaction is done, all metals exept for silver will have dissolved, you can pick up one drop of the hopefully pregnant solution with a glass stirring rod and let it fall off in a spotplate or on a filter paper. Or dip a filter tip in the solution with a pincet, wetting only milimeters is enough.
Add one or two drops of stannous and watch if there is any purple discoloring. If its too dark to see, add a drop of water until its dilute enough to see. Only purple is gold! Brown is not.
Oh, and iron dissolved in HCl looks just like gold chloride! Nice and deep yellow color.
To make things clear: the only thing i've ever panned was gold bonding wires from 50 grams of IC chips...and made a fortune..., not! LOL
8 years GRF membership and my curiosity got me this far.
So my help regarding placer gold is purely theoretical.
But I will get corrected by other members if talk nonsense.
I'm really curious what your replies and results are.
Good luck!
