Zinc Vs Activated carbon with GDA

[Ayham Hafez]

Activated carbon in best conditions in gold dressing agents or cyanide solutions can absorb only 20 grams of gold per 1 KG of activated carbon, while zinc can precipitate gold more than half of its weight, so 1 gram of zinc can precipitate 0.5 gram of gold, so for small scale like using 200 liters barrels I think zinc commercially much better also take shorter time than activated carbon, but what about the gold recovery rate for both, which is better?

 

[nickvc]

For reasonably small runs I’d go with zinc dust and plenty of agitation , I’d add a small amount of lye to help the zinc dissolve, you can then use aluminium foil to scavenge any remaining gold.

 

[Yggdrasil]

I think one of the main reasons for the use of AC is it can in a circuit and when loaded the values can be "unloaded" and the AC put back into use again.
Besides that it do nothing to the liquid, just adjust and run.
While when using Zinc you more or less destroy the solution don't you?

 

[Yggdrasil]

The AC will get progressively weaker, but can be reactivated again,
at least a few times until it is deemed spent and ashed for the last remaining values.

 

[Ayham Hafez]

The AC will get progressively weaker, but can be reactivated again,
at least a few times until it is deemed spent and ashed for the last remaining values.

I read about reusing AC, it gives you less than 80% of activity from the second use, with low grade ore maybe reusing AC is feasible but with high grade E-waste I don't think so, for example I have telecom plated equipment that gives 150 grams of gold only from plating gold, so reusing AC again not a good idea.

Since it a small scale, no mean for reusing the solution again, but in mines areas that have issues with water availability it worth

 

[Ayham Hafez]

For reasonably small runs I’d go with zinc dust and plenty of agitation , I’d add a small amount of lye to help the zinc dissolve, you can then use aluminium foil to scavenge any remaining gold.

JinChan supplier which is well-known GDA supplier in China, mentioned to me that increasing PH more than 11 will make issue with cementing with zinc, so I don't think using caustic soda is a good idea, but don't have an idea about using aluminum foils, I think zinc much reactive than aluminum in cementing process

 

[Ayham Hafez]

While when using Zinc you more or less destroy the solution don't you?

If adding zinc will destroy the solution, it will be a very good point, cause I don't know how we can stop the cyanide or GDA from redissolving precipitated gold again, hope someone have an idea about this.

 

[anachronism]

If adding zinc will destroy the solution, it will be a very good point, cause I don't know how we can stop the cyanide or GDA from redissolving precipitated gold again, hope someone have an idea about this.

Depending on the application you can electrowin the gold as part of a circuit.

 

[Yggdrasil]

If adding zinc will destroy the solution, it will be a very good point, cause I don't know how we can stop the cyanide or GDA from redissolving precipitated gold again, hope someone have an idea about this.

I do not think it is destroyed like that, but it will not be good for a second use.
These "Lurium" compounds are not on my list of sensible things to try.

Some of them have a degree of sense in mining.
If you are to selectively leach E-waste it is only going to be the plating and that is not where the majority of the values are.
Better use the pure chemicals for it then, Cyanide, Ferro/Ferri Cyanides, Iodide/Iodine leaches and so on.

Still that is just a small part of the values.

 

[Ayham Hafez]

I do not think it is destroyed like that, but it will not be good for a second use.
These "Lurium" compounds are not on my list of sensible things to try.

Some of them have a degree of sense in mining.
If you are to selectively leach E-waste it is only going to be the plating and that is not where the majority of the values are.
Better use the pure chemicals for it then, Cyanide, Ferro/Ferri Cyanides, Iodide/Iodine leaches and so on.

Still that is just a small part of the values.

The material that I want to process has 64% of its gold in plating areas, unlike normal PCB's which has more than 90% of gold in IC's, also have material that only has plated pins without IC's so 100% of its gold is plated.

 

[nickvc]

JinChan supplier which is well-known GDA supplier in China, mentioned to me that increasing PH more than 11 will make issue with cementing with zinc, so I don't think using caustic soda is a good idea, but don't have an idea about using aluminum foils, I think zinc much reactive than aluminum in cementing process

I was assuming you were using proper cyanide leaching not one of the pain causing Chinese alternatives that may well strip the gold well but are really not good in letting it go again.
With a normal cyanide solution if you add aluminium foil and it changes color to a beige or brown it shows you still have gold in solution and simply adding it after you think you have all your gold will scavenge virtually all the gold left, it is also very easy to recover your gold , rinse foil carefully with water and dissolve in HCl .