Elution of gold from strong base anion resin?

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All products coming out of China are a mix of ferro/ferri cyanides with various amounts of other metal solvents, chelates and oxidisers.

They will all dissolve gold along with other metals, they all work by having uv light from sunlight split the ferro/ferri cyanides into cyanide and ferric/ferro salts.

They will not dissolve more gold than straight ferro/ferri cyanide will but you will have the problem of lots of other metals in solution along with high levels of oxidisers, usually peroxides.

If you are working with small quantities of material then you can zinc out the gold for recovery.

Larger scale processing using carbon will give you major problems in two areas.

All the junk metals in solution will load on the carbon giving you low gold loadings on the carbon.

When you go to strip the carbon the high levels of junk metals will not allow the gold to be stripped in any meaningful amounts.

This means that your only realistic way to recover the gold from the carbon is to ash the carbon.

Why people would rather use a mix of chemicals containing one which is actually useful rather than just using the useful one is something I cannot understand, I put it down to marketing to people who do not have the knowledge to sort out the facts.

Always keep in mind that the Chinese sales people are only interested in selling their product so by making it sound as if it is the all dancing all singing answer to their needs, they prey on the uninformed at inflated prices.

Depending on the regulatory conditions where you are you can usually transport, store and use potassium ferrocyanide or potassium ferricyanide without restrictions.

Always keep in mind that uv light is essential to split the cyanide away from the complexes, this means nothing more than making up a solution of the potassium salt and exposing it to bright sunlight at pH 11.

You will also get an orange colour in the solution, this is the ferric part of the potassium complexes forming ferric hydroxide.

The formation of the ferric hydroxides is rapid if you use the potassium ferricyanide complexes, it is slower if you use the potassium ferrocyanide complexes as it takes time for the ferro salt to be converted to the ferro salt by the dissolved oxygen in the water.

The ferric hydroxide does not affect the leaching of the gold.

Deano
Deano,

Can the gold from the pregnant potassium/iron salts solution be absorbed onto resin instead of carbon?
 
At pH 11 the ferric complexes will precipitate out as ferric hydroxide leaving the cyanide in solution exactly as if you had started with sodium, potassium or calcium cyanide in the first place.

These cyanide complexes will last in solution just as long as standard cyanide complexes do and are used in leaches of all types in exactly the same way as normal cyanide is used, the only difference between the types is the method of formation.

Basically cyanide is cyanide, there are no differences apart from the starting materials and the requirement for the uv step.

Running the potassium ferri/o-cyanide complexes at 1 g/l will give you close to the mining industry standard of 1g/l sodium cyanide.

Deano
 
If you are really keen on spending money needlessly then feel free to use resin instead of carbon, see my earlier post in this thread.

Deano
 
If you are really keen on spending money needlessly then feel free to use resin instead of carbon, see my earlier post in this thread.

Deano
Hi Deano,
Haha, don't like spending money any more... however, I hear that eluting from resin is now possible as follows:
The strong base resin is used to collect/concentrate the gold from the leaching solution (I understand that Ambersep 21k can load 60g/L or 60ozt/cubic foot). The resin is then subjected to an ammonia solution (with a buffer) so strip any copper and then subjected to a solution of 2M Salt water with 0.1M sodium Sulphite, which strips the gold and renews the resin for anothe cycle. This process was devised in 2017. the testing team reused the resin 8 times with little degradation, however, I have been told that the resin gets locked after 8 cycles and has to be burned or fumed at that point to recover the PM's.

Your thoughts please mate

Kind regards
 
Many thanks for the info..
At pH 11 the ferric complexes will precipitate out as ferric hydroxide leaving the cyanide in solution exactly as if you had started with sodium, potassium or calcium cyanide in the first place.

These cyanide complexes will last in solution just as long as standard cyanide complexes do and are used in leaches of all types in exactly the same way as normal cyanide is used, the only difference between the types is the method of formation.

Basically cyanide is cyanide, there are no differences apart from the starting materials and the requirement for the uv step.

Running the potassium ferri/o-cyanide complexes at 1 g/l will give you close to the mining industry standard of 1g/l sodium cyanide.

Deano
 
There is always a big difference in results between solutions made up in the lab and solutions generated in the real world.

With resin you will always get lock up of gold from process solutions, the only variables are how much lockup and how many cycles does it take.

The more contaminant metals you have in your solutions the faster and more complete lockup will be.

From a practical standpoint most operators use the industry standard of activated carbon, there are always good reasons why alternatives are not in commercial use.

Deano
 
In virtually all cyanide processes there is a decision to be made about whether the time , effort and costs outweigh the returns and the art is getting the balance right , the mining industry will have looked at all variables and picked the best compromise .
Many assume that cyanide is the process that works the best and in some circumstances it does but it rarely recovers all the gold available which is where the decision has to be made over return and the variables I listed above but if you can get that balance right it pays off .
 
There is always a big difference in results between solutions made up in the lab and solutions generated in the real world.

With resin you will always get lock up of gold from process solutions, the only variables are how much lockup and how many cycles does it take.

The more contaminant metals you have in your solutions the faster and more complete lockup will be.

From a practical standpoint most operators use the industry standard of activated carbon, there are always good reasons why alternatives are not in commercial use.

Deano
Ok thanks Deano, I will consider using carbon in a column and compare to the resin. I will let you know what happens
 
Yes I understand. Many thanks
In virtually all cyanide processes there is a decision to be made about whether the time , effort and costs outweigh the returns and the art is getting the balance right , the mining industry will have looked at all variables and picked the best compromise .
Many assume that cyanide is the process that works the best and in some circumstances it does but it rarely recovers all the gold available which is where the decision has to be made over return and the variables I listed above but if you can get that balance right it pays off .
 
How long does the cyanide complex exist as a leaching agent after beeing subjected to UV light?
Can it be pumped from the surface into a heap for instance?
Or is this situation completely uncontrolable with leaching depth and so on?
Or is it so short lived that it has to be more or less be used in surface situation only?

Regards Per-Ove
Hi Per,

Sorry i just seen your post... i will have a vat leach in IBC tanks and then all dumped onto a leaching pad with a filter bottom where the solution will be collected.

:)
 
All products coming out of China are a mix of ferro/ferri cyanides with various amounts of other metal solvents, chelates and oxidisers.

They will all dissolve gold along with other metals, they all work by having uv light from sunlight split the ferro/ferri cyanides into cyanide and ferric/ferro salts.

They will not dissolve more gold than straight ferro/ferri cyanide will but you will have the problem of lots of other metals in solution along with high levels of oxidisers, usually peroxides.

If you are working with small quantities of material then you can zinc out the gold for recovery.

Larger scale processing using carbon will give you major problems in two areas.

All the junk metals in solution will load on the carbon giving you low gold loadings on the carbon.

When you go to strip the carbon the high levels of junk metals will not allow the gold to be stripped in any meaningful amounts.

This means that your only realistic way to recover the gold from the carbon is to ash the carbon.

Why people would rather use a mix of chemicals containing one which is actually useful rather than just using the useful one is something I cannot understand, I put it down to marketing to people who do not have the knowledge to sort out the facts.

Always keep in mind that the Chinese sales people are only interested in selling their product so by making it sound as if it is the all dancing all singing answer to their needs, they prey on the uninformed at inflated prices.

Depending on the regulatory conditions where you are you can usually transport, store and use potassium ferrocyanide or potassium ferricyanide without restrictions.

Always keep in mind that uv light is essential to split the cyanide away from the complexes, this means nothing more than making up a solution of the potassium salt and exposing it to bright sunlight at pH 11.

You will also get an orange colour in the solution, this is the ferric part of the potassium complexes forming ferric hydroxide.

The formation of the ferric hydroxides is rapid if you use the potassium ferricyanide complexes, it is slower if you use the potassium ferrocyanide complexes as it takes time for the ferro salt to be converted to the ferro salt by the dissolved oxygen in the water.

The ferric hydroxide does not affect the leaching of the gold.

Deano
Hi Deano,

Happy new year .:)

Just a thought... can i use a UV water sterilisation colum (i believe it is a mercury vapor tube broad spectrum UV) to activate the Ferro/Ferri instead of sunlight?

And how long does the leaching solution stay active?

Thanks
 
I believe there was a discussion earlier, a few years back and the conclusion was that 400nm UV light was sufficient.
My memory may be incorrect though.
It might have been 390 or 410.

Do a search on FerriCyanide, carbon cell and Anachronism as author.

Any broad spectrum UV in that region should be sufficient.
And as an answer to me earlier, Deano said that as long as it has been "activated"
The CN ion is ready for its job.
Regards Per-Ove
 
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