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What is the best black sand separator?

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Our Mantra:  Classify-classify-classify.

Gary is right on. Sometimes you can classify your way right out of otherwise difficult processes.

As for mechanical solutions, there are 2 types. 1) gravity  2) enhanced gravity/inertia

Sluices, miller tables, column separators are gravity types

Enhanced/ inertial are shaker tables, jigs, and centrifuges. I am biased this year - I like centrifuges. They recover well down to 40 micron gold. Jigs do even a little better. ( I want to play there next year).  I have less info on shaker table recovery, but what I have found is good recovery down to 100 microns, and fair even smaller. I have no experience with them as a primary concentrator. That is Gary's bailiwick.

To garyww and the adminstrator and Willthedancer et al:  If I didn't respect your knowledge base, I wouldn't be building a roughting table and Miller table now, nor would I be directing members of other prospecting forums here for all the good info found.   [-1st-]


This is basically (my) useless academic discussion.

Certainly to be sure, smelting black sands (the ore) is done routinely - in Assay Labs.
The step that is missing for the "home smelter" is inquarting with silver and using lead oxide
to gather the gold and silver but that would be way too dangerous for the home smelter
unless working in a lab with fume hood, proper furnace and exhaust discharge scrubbers.
So, do not do it!

But there is an alternative for the home smelter and that is inquarting with fine silver shot
or even finely chopped up scrap silver in place of the lead oxide. The silver well mixed with
the flux will gather the gold and settle to the bottom of the crucible. Would work okay with
the microwave furnace too. However the gold in the black sand should be visible. And then
alas, there is a problem - separating the gold from the silver and gold bead. Usually the
bead would be smashed flat to a thin wafer, and then the silver dissolved with nitric acid.
So another problem with sourcing and using nitric acid a home. One could use an
electrolytic cell to recover the purified silver as silver chloride - AgCl.

There are plenty of videos on youtube about inquarting and gold smelting, melting and also
purifying silver in a cell. But as the idiom states - "the devil is in the details".

As Gary said, smelting black sands by home smelting is usually a useless endeavour and the
gold is lost in the flux slag.

Now many of us do want to purify our gold. As pointed out by our learned members, better to
recover the gold with one of the concentrators or even a Miller Table, then simply torch melt
the gold in a fused silica crucible using anhydrous borax, make a bead or a wafer with a mold.
Torch melt the bead/wafer several times with the borax and get 95% - 99% pure gold.

We are going to do this just as the Artisan gold miners are taught to do it and also the goldsmiths
and jewellers do it in their back shops. Blacksmiths, the black powder gun guys, home re-loaders
do it too - smelting, melting, casting, forging, etc. with their furnaces and even their microwaves.  


PlacerPal summed it up. You can very easily ruin good gold by ending up with an ugly blob of crap that looks like a solidified piece of dark maple syrup with all of your gold inside. Not to pretty to look at and a waste of stuff you could have easily sold on ebay or to a jeweler.
Much easier and more cost effective, if your not set up to smelt, is to send it out and have it done but I'm wondering why a typical prospector type person would need to do this in the first place. Even fairly poor quality placer material is around 18-20k and it should be sold in it's native state.

I have spent quite a bit of time and effort trying to locate a fine gold separator (yes, separator not concentrator) called the Hydrostatic Vertical Table. It was invented by a man named Jim Humble of Las Vegas, Nevada. He was also one of the founders of Action Mining Services. I'm not fussy either; I'll settle for the separator or a set of specs to build one of my own.
This separator was reputedly a bit faster than a Miller Table and was supposed to give the operator a clean PM free of black sand in a catch cup at the bottom of the separator. In other words, no sweeping invisible gold particles from a table. It was also supposed to be able to recover gold in the -30 micron sizes.
Now, before anyone starts in about flatness factors and gravity separators and how E-towers "just don't work", study this unit first (I started a thread on this forum a while back about it) and keep an open mind. I can guarantee that there is not another gold recovery unit like it.
If this thing works even 1/10th as well as Mr. Humble claimed, it would walk all over any other recovery method.


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