Milled Quartz - Gold

[stoneware]

Lots of sulfides, aqua regia had little affect, weak cyanide with hydrogen peroxide did a much better job.

Curious why it took two days before the zinc began to cement the gold out. The zinc bits are rather large but I did stir the solution occasionally.

Electolizing onto steel wool did nothing, was it the oxidizer that inhibited the reaction.

 

[Lino1406]

Lots of sulfides, aqua regia had little affect, weak cyanide with hydrogen peroxide did a much better job.

Curious why it took two days before the zinc began to cement the gold out. The zinc bits are rather large but I did stir the solution occasionally.

Electolizing onto steel wool did nothing, was it the oxidizer that inhibited the reaction.

View attachment 52153
View attachment 52154

Did you add caustic soda for the zinc reduction, it may renew the metallic surface

 

[stoneware]

I suppose a mining company would consider this an ore worth processing .

My five pound sample run gave me a return of 0.2 grams, if it weren't for cyanide I would not bother as I only have 600 pounds of the milled ore.

After examining the spent ore there was still plenty of visible sulfides, I have since roasted the remaining ore.

Below is the remainder of the pulp that was leached using cyanide, the grey material on the left is baron of gold the material on the right sulfides after roasting.

 

[goldshark]

Most mining companies look for large tonnage ( 100's of millions of tons) to commit to a mining endeavor. I know of several properties in my area which contain 100,000 tons of ore averaging at least a half an ounce per ton Au, but it is still not worth it for them to set up, when you consider the cost of permitting these mines. Permitting is the biggest cost of bringing a mine on line in the US.

 

[orvi]

Zinc easily passivate in the near neutral conditions. Same with cementation with iron from only slightly acidic conditions. As Lino advised, you should add some base to revive fresh surface of zinc and better use zinc dust than chunks = larger surface area. You can also use sheet zinc metal, which is somewhat more convenient to use.

 

[stoneware]

Did you add caustic soda for the zinc reduction, it may renew the metallic surface

Thank you Lino1406, adding sodium hydroxide did the trick.

On a side note, I tried various leaches before and after roasting. Cyanide is by far showing the best results on roasted.

The first cyanide leach was made up from some very old stock that I've had on hand for the past five years. It appears that Cn has a shelf life,

 

[stoneware]

After using zinc to cement the metals out of the cn leach would there be any harm of returning the baron leach into the vat.

I would like to keep my liquid waste to a minimum, I would like to use the spent leach to peculate through the pulp to pick up any remaining values.

The remaining baron leach has been passed through an activated carbon filter, the liquor came out crystal clear. Is it alright to reuse I'll first check the ph.

 

[stoneware]

To get the most from my cyanide, I add gold plated junk into the catch basin along with a small addition of peroxide.

 

[stoneware]

I'm having trouble believing the amount of mud in the filter is all precious metals. The mud is from 100 pounds of milled ore to 100 mesh.

Later today I'm going to cupel a couple of grams of the mud.

 

[Alondro]

With sulfides, roasting followed by high alkalai flux smelting with iron to grab the sulfur and lead/bismuth as a collector works best. Also, the waste is basically just glass and rock. No toxic liquids!

 

[Yggdrasil]

If its all precious metals there is no need for cupelling.
Just roast it and dissolve in HCl/Peroxide then drop with SMB or other precipitant.

 

[stoneware]

If its all precious metals there is no need for cupelling.
Just roast it and dissolve in HCl/Peroxide then drop with SMB or other precipitant.

I'm only going to cupel 7 gram sample, I suspect some silver and some zinc from the cementing process that will need to be cleaned out.

 

[orvi]

I'm only going to cupel 7 gram sample, I suspect some silver and some zinc from the cementing process that will need to be cleaned out.

View attachment 52332

You cannot clean Ag out with cupellation. Of course some base metal impurities will go away with lead.

 

[stoneware]

You cannot clean Ag out with cupellation. Of course some base metal impurities will go away with lead.

I'm aware that cupelling will only leave the precious metals behind as a button, I'm doing this procedure the qualify the mud.

HCL/Peroxide as suggested will not react with any silver that maybe present.

 

[Yggdrasil]

I'm only going to cupel 7 gram sample, I suspect some silver and some zinc from the cementing process that will need to be cleaned out.

View attachment 52332

HCl will take the Zinc and most impurities and leave the Ag and Au behind.
Or if you have Nitric available the Nitric will take most if not all impurities including Silver and leave the Gold behind.
After roasting of course.
This will need only a minute amount of Nitric, a couple of ml plus the same amount if water would take care of it.
Then drop the Silver by cementing or as chloride.
At this point you will have separated the Gold and Silver so you will know whats in there.
By cupelling you will have to add Lead and use a cupel with heating.
It will cost more and take more time.

And then you need to part it anyway

 

[orvi]

I'm aware that cupelling will only leave the precious metals behind as a button, I'm doing this procedure the qualify the mud.

HCL/Peroxide as suggested will not react with any silver that maybe present.

I won´t be that straight with statement silver won´t react depends. Silver chloride is not completely insoluble in HCL. Some of it dissolve. And silver is easily attacked by this mixture. Only thing that matters is quantity of the silver present. If it isn´t that much, and you use excess of HCL, you conveniently get everything into the solution.

Most of the times not practical at all, but you can find yourself lucky Rose/red 18k gold is also conveniently dissolved in AR despite silver content. And all silver will react to form AgCl. Now, as you said, cupellation will give you the result which help you decide which route you can choose.

 

[stoneware]

Bottom image is when i ran out of propane, the more volatile metals had already oxidized. Now that copper is rearing her head If any precious metals are present I'll have a bead.

Top image unsuccessful Portland crucible melt, but from the color of the oxides this would be a good indicator of what is in my ore.

 

[orvi]

Bottom image is when i ran out of propane, the more volatile metals had already oxidized. Now that copper is rearing her head If any precious metals are present I'll have a bead.

Top image unsuccessful Portland crucible melt, but from the color of the oxides this would be a good indicator of what is in my ore.

View attachment 52338

View attachment 52339

It is very strangely coloured. Hard to say what you should do with it next without proper analysis. How hot your furnance can be ? 1000°C ? Higher ? 1200°C ? If it is only AuAgCu mixture, you should be able to nicely drive off all lead and easily oxidizable metals (such as Zn) and be left with nicely molten alloy - since mixtures of AuAgCu have always lower m.p. than former pure metals. It can go below 900°C in some cases.

Depending on Au content, nitric parting/"inqartation" would be considerable. With low Ag, I would go with AR digestion after cornflaking molten alloy into the water. But since the colour, I would try nitric leach first. Try on the small sample 1:1 HNO3/distilled H2O. Boil and observe.

 

[stoneware]

After cupelling, no gold.

 

[stoneware]

Using large pieces of zinc to cement out the gold did not work all that well, brought down just under 4 grams.

Activated carbon water filter after ashing.

Not too shabby from 100 pounds of milled quartz, found as float.