Help separating gold front iron ore

[Mlandri]

I'm new to this arena, so appreciate any/all asdistance.

Having a difficult time separating gold from iron rich ore. I get best results using Chapman's flux. However, the gold remains swirled in glass. I don't believe that my melt is adequately liquid. Hence, the metals are not settling out.

Attached pic shows an example of the problem. Was tough getting a good view but pic should be adequate for one to see gold swirled in glass and the general problem. Thanks in advance for your help!

 

[g_axelsson]

I'm not an expert in ores but I know what the first question will be...

What did the assay tell you?

No, I don't see any gold in the picture. But if you can see the gold in the slag it would be easy to crush and pan the gold out. Use a shaker table if you have larger amounts of slag.

Göran

 

[bswartzwelder]

You may have to thin out your flux. That would allow the gold to settle out more easily. I am by no means versed in the use of flux, but I have seen numerous posts oh what to use to make it thinner. The search function should be your friend here, but it may take a lot of reading.

 

[Harold_V]

Göran's comment is key to anything that should be considered. What did the head assay show?

Be advised that gold and iron will readily alloy. Assuming you have ore that yields iron, and it contains gold, there's little reason for the gold to not be alloyed with the iron.

If you suspect you have gold in the flux, an assay will resolve the issue. What you see may or may not be gold.

Harold

 

[GotTheBug]

Just a guess, but it looks like you're not using enough flux and not letting it cook long enough. If I remember correctly, 30g of ore or concentrates to 90g flux, then pour into a conical mold.

 

[Mlandri]

All,

Appreciate the comments! I used Chapman's flux. My understanding is that it is useful for separating iron from gold. Seems to oxidize the iron pretty well, but not well enough I suspect.

I increased the amount of borax to 4 times original proportions. Did a really good job reducing viscosity of the melt. Also, increase the ratio of flux to concentrate to greater than 3:1.

Some improvement in overall result, but still not great. Bottom line is that I'll need to send some samples off to a pro. I hadn't been looking for gold originally. Instead, I was smelting iron from local limonite and gossan concretions. Hence, I don't have assays for this ore. Finding what appears to be gold was a suprise.

Anyone have an assay company the can recommend? Would be much appreciated. Apparently, I'm much better extracting iron than "gold"!

 

[nickvc]

You could do some simple tests to see if you actually do have gold or get a member close to you to run some tests for you it's not difficult, it won't give you definitive answers but at least you will know its gold and not brass or some other combination of metals and if it's proven to be gold then an assay might well be in order.
Hoke outlines several tests and if you have the chemicals they are easy to perform and if you find you do have gold then simply dissolve a known weight, say 10 grams, and see how much you recover, this will give you a good idea of its worth your time and effort.

 

[Mlandri]

I'm fine working with 3000 F furnaces, but don't like working with caustic chems used for dissolving and then recovering gold. Im ok with the HCL and tin solution to test for the presence of gold, so I'll mix up a small batch. However, i dont have the safety equipment for mixing Aqua Regia, etc. I'm a Chem wimp. I'd rather pay $50 or $60 to a professional to do the work!

 

[butcher]

Pyrite or fools gold will flake or crush to powder, gold is malleable.
Gold has a high specific gravity, and can be panned, pyrite or fools gold, will float away even before much of your sand will.
Pyrite or fools gold, will form a glass slag, with your flux, gold will either form beads of gold, or combine into a lump of metal in the bottom of your cone mold when poured, (whether it forms beads, or a heavy lump of melted metal, that will sink to the bottom of your cone mold depends on the flux used, and conditions you use during the process).


A very simple test for gold in sulfide ore, powder some of the sulfide ore you suspect has gold, fuse a pinch of this in a surplus mix of one part ammonium chloride, and two and a half parts of ammonium nitrate, let the melted fusion cool, crush and dissolve it in a few drops of HCl acid, take this sample, in a spot plate or with a Qtip, and add a drop of stannous chloride, and look for the Purple of Cassius color, as a positive for gold, this will not tell you how much gold or if you have enough gold to recover in a smelting or leaching process or can even recover gold from the ore profitably, but it can indicate if gold is in the ore, or not.

 

[Mlandri]

Awesome.will definitely do the stannus chloride tests! Specific gravity checks are what caused me to search for heavier minerals in my iron. I was getting vals a bit more than expected. I don't have good equip for small samples unfortunately. I dont trust measurements where samples are 5 grams or less.