Elution of gold from strong base anion resin?

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TrickyDicky

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Joined
Jul 14, 2016
Messages
13
Dear All,

Does anyone know the best, easiest, most economical way to recover gold from resin, and once back in solution, the easiest way to get the gold metal?

The resin has to be reused so burning is not am option.

Many thanks if you can help.
 

TrickyDicky

Member
Joined
Jul 14, 2016
Messages
13
Dear All,

Does anyone know the best, easiest, most economical way to recover gold from resin, and once back in solution, the easiest way to get the gold metal?

The resin has to be reused so burning is not am option.

Many thanks if you can help.

Dissolve the resin in a solvent and filter.
Edit: and distill the solvent off to reclaim the resin.
Many thanks for the reply Martijn, however the criteria was that the resin had to be reused, so dissolving or burning is not an option, I was thinking about elution with salt water?
 

TrickyDicky

Member
Joined
Jul 14, 2016
Messages
13
Hi Lino1406, thanks for your reply, I understand that some of the gold producers are using thiosulfate leach on to resin and then eluting the gold and re using the resin, however, they are keeping the process proprietary (secret).

From what I understand the elution from the resin is a 2 part process, first any copper is removed by Ammonia solution (with a buffer) and then the gold is eluded with a salt solution..

This is what I need to find out...

Thanks
 

Lino1406

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Joined
Nov 1, 2007
Messages
2,118
Location
Israel
To see the problem, google:
Recovery of gold from pregnant thiosulfate solutions... a sulfur problem
 

Deano

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Joined
Feb 23, 2014
Messages
359
When you are looking at recovery methods the first thing you do is to look at what the mining industry uses.

There are literally hundreds of research papers available which are beautifully researched and written but all of them will have a fatal flaw in the processing which prevents them from commercial use.

Firstly, what methods are used in recovery by industry. They are activated carbon, ion exchange resin and zinc precipitation.

Zincing is a multi-step expensive process which the industry could not get rid of fast enough when activated carbon was introduced.

Activated carbon was a literal game changer for the gold industry, much simpler and cheaper than zincing.

Unfortunately it has poor loading characteristics when used for gold thiosulfate and thiourea solutions.

Ion exchange resin suffers from a couple of defects, it is expensive to buy and it locks up a lot of gold in the beads after several cycles of loading and stripping. The last thing you want is to have a large gold inventory locked in your resin.

Stripping is usually done with sulphuric acid and causes high resin losses from osmotic shock.

If resin is used with gold thiosulfate or thiourea there are also problems with precipitation of silver complexes and sulfur compounds.

Practically the only way to recover gold from thiosulfate and thiourea solutions in small scale is by zincing or electrowinning if the gold tenor in leach solutions is high enough, you will still get a lot of sulfur on your plates if you electrowin.

Deano
 

Lou

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Rhodia Drive
I would definitely recommend against elution. Just burn the resin. Strong base anion exchangers are not hugely expensive...150-200/cubic foot. That puts the cost at probably less than a dollar an ounce.
 

TrickyDicky

Member
Joined
Jul 14, 2016
Messages
13
Hi Deano,

Many thanks for the reply,

I have been studying this for a long time now and keep going down different avenues only to find that yes, there is a fatal flaw in most of the methods.

I don't have the option of spending lots of money, and the situation is complicated, I have fire assay tests done which indicate around 1.8ozt Au/ton plus other nice stuff and we have a lot of the ore.

We have tried everything from heating, flotation, gravity separation, etc, and nothing has worked (except smelting with a collector metal, but to expensive to do).

Our last option is leaching, but cyanide is not an option for us.

Any help is always appreciated

Kind regards

When you are looking at recovery methods the first thing you do is to look at what the mining industry uses.

There are literally hundreds of research papers available which are beautifully researched and written but all of them will have a fatal flaw in the processing which prevents them from commercial use.

Firstly, what methods are used in recovery by industry. They are activated carbon, ion exchange resin and zinc precipitation.

Zincing is a multi-step expensive process which the industry could not get rid of fast enough when activated carbon was introduced.

Activated carbon was a literal game changer for the gold industry, much simpler and cheaper than zincing.

Unfortunately it has poor loading characteristics when used for gold thiosulfate and thiourea solutions.

Ion exchange resin suffers from a couple of defects, it is expensive to buy and it locks up a lot of gold in the beads after several cycles of loading and stripping. The last thing you want is to have a large gold inventory locked in your resin.

Stripping is usually done with sulphuric acid and causes high resin losses from osmotic shock.

If resin is used with gold thiosulfate or thiourea there are also problems with precipitation of silver complexes and sulfur compounds.

Practically the only way to recover gold from thiosulfate and thiourea solutions in small scale is by zincing or electrowinning if the gold tenor in leach solutions is high enough, you will still get a lot of sulfur on your plates if you electrowin.

Deano
 

TrickyDicky

Member
Joined
Jul 14, 2016
Messages
13
I would definitely recommend against elution. Just burn the resin. Strong base anion exchangers are not hugely expensive...150-200/cubic foot. That puts the cost at probably less than a dollar an ounce.
Hi Lou,

Thanks for the reply,

I need to reuse the resin to save costs for the moment and I am based in the Philippines so good equipment is not available and if it is it is extremely costly, However, I would appreciate any info on the ion exchangers.

Kind regards
 

Deano

Well-known member
Joined
Feb 23, 2014
Messages
359
If you cannot use flotation to concentrate the gold values then you have two options.

The first is to either have your ore toll treated by someone who can use cyanide or to sell the ore to a similar operator.

The second is leaching with either carbon recovery or zinc precipitation.

If you are prohibited from using cyanide you can either use a ferro or ferri cyanide salt depending on local regulations, this is actually cyanide leaching but in most places the regulations have not caught up with this method.

Thiosulfate leaching with zinc precipitation is usually allowable but is more complex and more expensive than cyanide.

Depending on the ore matrix you can use acid thiocyanate with carbon recovery, if you have a carbonaceous matrix the acid cost will be high.

Again, depending on the ore matrix, you can use neutral pH hypochlorite leaching with carbon recovery or chlorine leaching also with carbon recovery.

The thiocyanate, hypochlorite and chlorine methods all have the downside that no metal parts of the plant can contact the leach solution.

You cannot use resins for recovery on the hypochlorite or chlorine leaches, these oxidisers will destroy the functional groups on the resin.

Deano
 

AJLnz

Member
Joined
Aug 14, 2020
Messages
8
Hi Deano
With flotation have you ever used IXOM products.
I have a refractory ore with 9,87g/t and cyanide gives 95% recovery within 2hr but it's restricted use here. (BLEG test)
Can you suggest another lexivant that will match cyanide maybe.
I have tested a Chinese product called Henan LV JIN that is suppose to replace cyanide but more green. Not very successfully.
 

TrickyDicky

Member
Joined
Jul 14, 2016
Messages
13
If you cannot use flotation to concentrate the gold values then you have two options.

The first is to either have your ore toll treated by someone who can use cyanide or to sell the ore to a similar operator.

The second is leaching with either carbon recovery or zinc precipitation.

If you are prohibited from using cyanide you can either use a ferro or ferri cyanide salt depending on local regulations, this is actually cyanide leaching but in most places the regulations have not caught up with this method.

Thiosulfate leaching with zinc precipitation is usually allowable but is more complex and more expensive than cyanide.

Depending on the ore matrix you can use acid thiocyanate with carbon recovery, if you have a carbonaceous matrix the acid cost will be high.

Again, depending on the ore matrix, you can use neutral pH hypochlorite leaching with carbon recovery or chlorine leaching also with carbon recovery.

The thiocyanate, hypochlorite and chlorine methods all have the downside that no metal parts of the plant can contact the leach solution.

You cannot use resins for recovery on the hypochlorite or chlorine leaches, these oxidisers will destroy the functional groups on the resin.

Deano
Thanks Deano,

This is a big help. Please could you be more specific with the ferric or Ferro cyanide salt to see if it is available here?

Kind regards
If you cannot use flotation to concentrate the gold values then you have two options.

The first is to either have your ore toll treated by someone who can use cyanide or to sell the ore to a similar operator.

The second is leaching with either carbon recovery or zinc precipitation.

If you are prohibited from using cyanide you can either use a ferro or ferri cyanide salt depending on local regulations, this is actually cyanide leaching but in most places the regulations have not caught up with this method.

Thiosulfate leaching with zinc precipitation is usually allowable but is more complex and more expensive than cyanide.

Depending on the ore matrix you can use acid thiocyanate with carbon recovery, if you have a carbonaceous matrix the acid cost will be high.

Again, depending on the ore matrix, you can use neutral pH hypochlorite leaching with carbon recovery or chlorine leaching also with carbon recovery.

The thiocyanate, hypochlorite and chlorine methods all have the downside that no metal parts of the plant can contact the leach solution.

You cannot use resins for recovery on the hypochlorite or chlorine leaches, these oxidisers will destroy the functional groups on the resin.

Deano

If you cannot use flotation to concentrate the gold values then you have two options.

The first is to either have your ore toll treated by someone who can use cyanide or to sell the ore to a similar operator.

The second is leaching with either carbon recovery or zinc precipitation.

If you are prohibited from using cyanide you can either use a ferro or ferri cyanide salt depending on local regulations, this is actually cyanide leaching but in most places the regulations have not caught up with this method.

Thiosulfate leaching with zinc precipitation is usually allowable but is more complex and more expensive than cyanide.

Depending on the ore matrix you can use acid thiocyanate with carbon recovery, if you have a carbonaceous matrix the acid cost will be high.

Again, depending on the ore matrix, you can use neutral pH hypochlorite leaching with carbon recovery or chlorine leaching also with carbon recovery.

The thiocyanate, hypochlorite and chlorine methods all have the downside that no metal parts of the plant can contact the leach solution.

You cannot use resins for recovery on the hypochlorite or chlorine leaches, these oxidisers will destroy the functional groups on the resin.

Deano
 

AJLnz

Member
Joined
Aug 14, 2020
Messages
8
Thanks Deano,

This is a big help. Please could you be more specific with the ferric or Ferro cyanide salt to see if it is available here?

Kind regards
You could try the Chinese product if you working with actual gold element.
It can be recovered on carbon and then washed as per cyanide process.
 

TrickyDicky

Member
Joined
Jul 14, 2016
Messages
13
You could try the Chinese product if you working with actual gold element.
It can be recovered on carbon and then washed as per cyanide process.
I have a different 'Chinese Product' not the LV one, and it definitely leaches gold as i did a test in some old computer scrap printed circuit boards, getting the gold into solutiin is easy, getting the gold back out of solution is problematic to say the least. I need to know it works before trying on the 'ore' so I am not chasing my tail 😁
 

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AJLnz

Member
Joined
Aug 14, 2020
Messages
8
You need to deaerate the solution and then use zinc and a bit of lead acetate not lead nitrate as per cyanide then sulferic wash to remove extra zinc before smelt.
 

Deano

Well-known member
Joined
Feb 23, 2014
Messages
359
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
 

TrickyDicky

Member
Joined
Jul 14, 2016
Messages
13
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
Thanks Deano,

Excellent info, if/when it works, I will buy you a pint or two...!

I will try and get some of the suggested chemicals, what sort of solution concentration do I need?

Kind regards
 

Yggdrasil

Well-known member
Joined
Oct 30, 2015
Messages
871
Location
Northern Mindanao, Philippines
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
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
 
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