Turn 999 gold to 9999 gold

[giahylxag]

I have around 1kg of 999 gold range from 9991 to 9997. Impurity is only silver.
I want to turn them to 9999 gold.
Can one AR refine help?
Or I may waste my time because silver content is so low already I can't filter them out anymore.

Sorry about the inverted image

 

[Yggdrasil]

I have around 1kg of 999 gold range from 9991 to 9997. Impurity is only silver.
I wan't to turn them to 9999 gold.
Can one AR refine help?
Or I may waste my time because silver content is so low already I can't filter them out anymore.
View attachment 62292
Sorry about the inverted image

I think your only option is an electrolytic cell.

 

[anachronism]

Looks good as it is- really good.

I'd genuinely ask why you want to take it to 4 x 9 - is there a particular reason apart from personal satisfaction? That's a perfectly good reason in itself, and I'm simply intrigued.

 

[nickvc]

Another wet refine may improve the purity but I would have done this when you first precipitated the gold and after good washes with water and HCl , then redissolve using different reagents and once filtered using a different precipitant.

 

[anachronism]

If the sole contaminant is silver Nick wouldn't the purity be increased by better filtering or is it simply too small a quantity to catch? Or is it a simple process of washing the powder in HCl more? I'm shooting the breeze tbh, because it's such a tiny tiny amount.

Edit: I'm sure I recall Lou having a method a thread about 5 x 9 gold if I remember correctly.

 

[giahylxag]

Looks good as it is- really good.

I'd genuinely ask why you want to take it to 4 x 9 - is there a particular reason apart from personal satisfaction? That's a perfectly good reason in itself, and I'm simply intrigued.

Well,
I have several 1kg Swiss bars at home
I want to add this bar to my stack and forget it
I just want to make it 9999 like other bars.
If the process proved too costy then ok I will not do it.
I can say personal satisfaction is my reason

I think your only option is an electrolytic cell.

I don't know where to begin with. Apparently not many people use this method than large refineries.
There are some videos of streetips on youtube but I am not sure I can achieve the same result

 

[anachronism]

Thanks for the explanation! I'd suggest it will be more trouble than it's worth but I do appreciate that one bar will trigger the old OCD chip, so I really do understand.

Jon

 

[nickvc]

One question is your assay from an xrf reading?

 

[Darkthirty]

If the sole contaminant is silver Nick wouldn't the purity be increased by better filtering or is it simply too small a quantity to catch? Or is it a simple process of washing the powder in HCl more? I'm shooting the breeze tbh, because it's such a tiny tiny amount.

Edit: I'm sure I recall Lou having a method a thread about 5 x 9 gold if I remember correctly.

If Ag is the contaminant, wouldn't HNO3 be the solvent?

 

[Yggdrasil]

If Ag is the contaminant, wouldn't HNO3 be the solvent?

Not after it has become a bar, then you will just dissolve traces on the surface.

 

[4metals]

If I had to do this I would start out by digesting in Aqua regia followed by adding ice until it is almost freezing. The Silver Chloride that has dissolved in the acid is at its lowest solubility in the cold, and extreme cold is best. Then, while it is still very cold, filter it through a fine filter to catch the Silver Chloride that is insoluble in the cold.

This is the easiest fix and it may be all you need. Did your first aqua regia dissolve and filtration include chilling?

 

[Darkthirty]

Not after it has become a bar, then you will just dissolve traces on the surface.

That post was in reference to final rinses before melting. "Or is it a simple process of washing the powder in HCl more?"

 

[FrugalRefiner]

Personally, I am a fan of Lou's washing procedure as he described in Gold has been refined and melted, now has orange hue. Since silver is your primary contaminant, the concentrated HCl wash would probably help.

Dave

 

[Yggdrasil]

That post was in reference to final rinses before melting. "Or is it a simple process of washing the powder in HCl more?"

Yes but the OP has it in bar form already.

 

[giahylxag]

One question is your assay from an xrf reading?

it is

If I had to do this I would start out by digesting in Aqua regia followed by adding ice until it is almost freezing. The Silver Chloride that has dissolved in the acid is at its lowest solubility in the cold, and extreme cold is best. Then, while it is still very cold, filter it through a fine filter to catch the Silver Chloride that is insoluble in the cold.

This is the easiest fix and it may be all you need. Did your first aqua regia dissolve and filtration include chilling?

I did not refine this bar, I bought it.
I may test this trick, but my concern is that silver content is so low already that AR process is not sufficient.

Yes but the OP has it in bar form already.

Yes, i bought the bar with a slightly bargain price, and some other small bars

 

[Shark]

999 gold will go into AR just fine. In bar form it will still work just quite a bit slower. Melt and pouring to shot is fairly straight forward and will save quite a bit of time.

 

[nickvc]

I’m not sure I would trust the xrf result, try one of the Swiss bars and see what the xrf says about it.

 

[4metals]

I may test this trick, but my concern is that silver content is so low already that AR process is not sufficient.

If when you digest it and cool it you should see the insoluble chlorides, a gram will be visible. If you see it and filter it out the assay will be closer to .9999. After you drop the gold try some of the wash methods mentioned earlier on the sponge. That will clean it up even more.

 

[stella polaris]

If when you digest it and cool it you should see the insoluble chlorides, a gram will be visible. If you see it and filter it out the assay will be closer to .9999. After you drop the gold try some of the wash methods mentioned earlier on the sponge. That will clean it up even more.

The wash method is suitable for fast turnover and professional refiners. What if I, as an amateur, would let the sponge lay in HCl (or nitric) for a couple of weeks/months before I do the water washing. I just give it more time to react with the unwanted metals. The gold is there and I have no hurry to final product. Would it help much or just be the same?

 

[Xing]

electrolizing is better. but i think it is no need to increase the impurity, the price is little difference, if do further refining, it cost too high and may lost the recovery.