Gold refining

[deandadnaed]

You can also put the button in dilute sulphuric acid and warm it. Leave it there and you will see the borax disappear.

Thank you very much!
I’ll try it! Hopefully I’ll be having less this problem as I develop skills when melting.



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[Jordan1]

Others may have a better idea but in my case when silver is the major contaminant it is usually related to poor filtering. Once I reached a point where I examined my filters a bit more thoroughly and made changes accordingly I found my quality made a serious improvement.

Hi Shark,

You are right. I took my time and washed the gold properly with hcl and distilled water and achieved 99.99%.

Parting with nitric and the wash i have found the most important part to getting the purest metal possible.

Thanks

 

[goldsilverpro]

Others may have a better idea but in my case when silver is the major contaminant it is usually related to poor filtering. Once I reached a point where I examined my filters a bit more thoroughly and made changes accordingly I found my quality made a serious improvement.

Hi Shark,

You are right. I took my time and washed the gold properly with hcl and distilled water and achieved 99.99%.

Parting with nitric and the wash i have found the most important part to getting the purest metal possible.

Thanks

I wouldn't trust XRF to guarantee that that purity is correct.

 

[Jordan1]

Others may have a better idea but in my case when silver is the major contaminant it is usually related to poor filtering. Once I reached a point where I examined my filters a bit more thoroughly and made changes accordingly I found my quality made a serious improvement.

Hi Shark,

You are right. I took my time and washed the gold properly with hcl and distilled water and achieved 99.99%.

Parting with nitric and the wash i have found the most important part to getting the purest metal possible.

Thanks

I wouldn't trust XRF to guarantee that that purity is correct.

Why is that goldsilverpro? The metal was tested with 2 xrf machines.

What would you trust for a accurate assay?

 

[anachronism]

To be honest it depends on who is buying your material as to whether an xrf is accurate enough.

If your buyer uses one and it says 99.99% then everyone is a winner.

 

[FrugalRefiner]

Why is that goldsilverpro? The metal was tested with 2 xrf machines.

What would you trust for a accurate assay?

See Help with XRF results (99.70% Au 0.30% Ni).

Dave

 

[modtheworld44]

To be honest it depends on who is buying your material as to whether an xrf is accurate enough.

If your buyer uses one and it says 99.99% then everyone is a winner.

anachronism

I agree with you 100%.

My guy buy's gold based on xrf.I tested the accuracy of his gun myself.I took him a 61.2 gram button that I left the top fire scaled.The bottom and sides shot 99.99% and the top shot 99.98%.He told me at that time he would pay 95% of spot,I declined the offer because I was looking for at least 97%.I then went home and centered the button with sodium nitrate and pickled it in dilute nitric,this was done six times across 2 and half hours.The last centering left a brand new crucible with crystal clear borax.The new weight ended up being 61.1grams and was re-shot at 99.99% on all sides of the button and he then payed me 97% of spot and sent 10 lbs of pins home with me to be refined.Thanks in advance.



modtheworld44

 

[Lou]

Looks are everything!!

 

[anachronism]

Looks are everything!!

That's me screwed then Lou.

 

[goldsilverpro]

Looks are everything!!

I totally agree with Lou. Experience will tell a knowledgeable person whether a bead, button, or bar is at least 99.95% pure, or not, by just looking at it after it cools. That's why I never keep the torch on the bar, as it cools, to get those concentric circles. I wanted my expert buyer to see the crystal and the pipe. When I had my last refinery, I shipped gold at least once a week, always got paid for pure gold, and never had a lot bounce back, all based on visual appearance, at both ends. I also never shipped any discolored gold that I could have easily made look good. Although rare, any gold with Pt Gp chicken tracks or discoloration or any other visual defect was re-refined. The small bead in the photos above, would be unacceptable and would be re-refined. There's more problems with it than a little slag on it.

 

[Jordan1]

Hi,

I would like to know if anyone on the forum has processed gold / silver dore bars from the mines ?

I know that the purity varies from mine to mine, though wanted to get a good idea of gold / silver % and other contaminants in the dore bars?

Thanks

 

[Jordan1]

Others may have a better idea but in my case when silver is the major contaminant it is usually related to poor filtering. Once I reached a point where I examined my filters a bit more thoroughly and made changes accordingly I found my quality made a serious improvement.

Hi Shark,

You are right. I took my time and washed the gold properly with hcl and distilled water and achieved 99.99%.

Parting with nitric and the wash i have found the most important part to getting the purest metal possible.

Thanks

Goldsilverpro what assay machine would you trust to give a accurate assay? Aa, icp?

Please let me know

I wouldn't trust XRF to guarantee that that purity is correct.

 

[goldsilverpro]

For high purity gold, ICP. For everything else, fire assay.

 

[cuchugold]

If anyone wishes to make a small experiment: After you have your "clean" aqua regia, and before reduction of the metal, drop a pH strip in the clear liquid, and start dropping a solution of sodium hydroxide till the pH strip is about color 6.5 (near neutral). Wait for the few solids to coalesce and settle, and then decant. Adding a little zinc or barium chloride to the initial solution helps in collecting the solids. This really gets the rest of the silver out, and a few other things too. If it doesn't, I'll refund every penny you paid for the free advice.

You can start selling the expensive assay equipment soon after. You won't need it anymore. :G

edit: This, in 'first principle' is parallel to GSP's dilution method, but without the extra water. But do not think too hard about it. The experiment is easier to make than the thinking.

 

[Deano]

Dore bars from commercial mines vary dramatically in their contaminant contents, there is no one size fits all.

Silver runs from 1 to 20%, often around 10%

Copper runs from 1 to 30%, sometimes more, very mine ore type dependent.

Iron from electrowin steel wool varies as to the actual method detail of aciding it out before smelting.

Levels of other metals such as lead, nickel and chrome depend on both the ore types and treatment methods, usually in single digit % or less.

Overall purity of the bars can run from 30 to 95% gold, below 30% the penalties really hurt.

Deano

 

[4metals]

I can understand the refining costs going up for doré gold which is below 30% gold but I am surprised it doesn't go up for higher silver. I worked with an Asian refinery which routinely received doré from a region with the silver content at 23%. Very much a pain to refine!

I would think silver in excess of 15% should carry a penalty as well, unless they already bang the guy with ridiculous silver refining rates! Then they just deal with it!

 

[kuli]

Hi again,

I put cca 100g of phone board.
After filtering in put SMB. a little bit 10g.
If you look at solution there is nothing.
Where did i missed?
Help please. I put first SMB to cold water and then drop to solution.

regards

 

[anachronism]

If you used 100g of phone board then the chances of you seeing gold are slim to none.

 

[nickvc]

If you used 100g of phone board then the chances of you seeing gold are slim to none.

:roll:

 

[g_axelsson]

Hi again,

I put cca 100g of phone board.
After filtering in put SMB. a little bit 10g.
If you look at solution there is nothing.
Where did i missed?
Help please. I put first SMB to cold water and then drop to solution.

regards

As stated by others too, there is very little gold on 100g of phone boards. Most of the gold is just flash plated.
A lot of the gold in cellular phones are hidden inside the circuits in the form of bond wires.

If it was ordinary phones with a cable then there is almost no gold at all in them.

Göran