Eco-goldex CYANIDE Leach

[Deano]

Things which make me wonder are;

1 Why would anybody use a leach formulation containing cyanide amongst a raft of other chemicals when they can just use a straight cyanide or ferrocyanide leach at a cheaper price and with less side reactions.

2 Why would anybody accept the marketing blurb as gospel without at least trying activated carbon.

The bond strength between gold and cyanide is multiple orders of magnitude greater than the bond strength between gold and any other ligand in these formulations. This means that any gold solubilised by a leach containing cyanide amongst other ligands will have the gold in the cyanide complexed form.

Other ligands may leach the gold faster than cyanide but the presence of cyanide will ensure that the final complexed form of the gold will be as the cyanide form.

The presence of chemical oxidants and multiple ligands in the leach formulations will ensure that not only will these formulations leach many more base metals than straight air oxygenated cyanide leaches but that there will be major problems in the recovery stage.

Often the claim of the gold not adsorbing on activated carbon is made either to cover the fact that there is no cyanide present (eg thiourea leach) or that the carbon is swamped with both dissolved base metal complexes and leach components.

If you have some great desire to use these leach types at least try activated carbon for yourself and get some real numbers on the gold adsorption.

Run the leach solution very slowly through a column of carbon and use AAS to see what actually happens to the gold.

My suspicion is that the gold will load onto the carbon but it will require ashing of the carbon and aqua regia digest of the ash to recover the gold.

If the gold does not load onto the carbon it is fair proof that there is no free cyanide present in the leach.

Keep in mind that thiourea is a listed carcinogen.

Deano

 

[finegold]

Good evening all. This tread was a very interesting read, though I have some concerns. Ive read all 8 pages, something I doubt a new member will do, they will read as far as "I dissolved the gold". At this point I feel that GRF is only acting as free advertisement for a foul tasting candy bar in a shiny wrapper(Eco-goldex).
This is obviously a cyanide leach and potentially deadly.
Deano said at least twice that this concoction had too many reagents in it,I believe he is well respected in this field,and just to get my point across this is what I got out of the whole thread....ferrocyanide+h2o+uv light=cyanide leach, recover values with activated carbon,incinerate,AR. and im not a chemist and have no knowledge of this process at all,i have however used potassium cyanide in case hardening of gun parts....hated every minute of it.
I guess the whole point of this post is that pandoras box has been opened and as long as this thread is top of the list,people are going to read (part of) it. My solution would be to create a new "prosseses" section labled cyanide and place this thread there,and perhaps the poor mans cyanide leach could progress...I think it has value,but almost none of the safty issues are covered in this thread,if it had its own section I think 95% of noob wouldn't even read just because of the word cyanide,and while frugalrefiner wisely added that word to the post,eco still shows up first.....funny how the brain works
Harold V said read hokes and then read again until you understand ....the same applies to this wonderful forum,however only a small sliver of visitors will take that advice,everyone is looking for instant gratification

 

[goldsilverpro]

I totally agree with Deano when he said, "Why would anybody use a leach formulation containing cyanide amongst a raft of other chemicals when they can just use a straight cyanide or ferrocyanide leach at a cheaper price and with less side reactions", at least as far as the cyanide is concerned. In my opinion, for working with gold and silver, cyanide is as close to a wonder chemical as there is. I have used it for 50 years and for about 20 of those years, I used it daily. As a professional refiner, I would be lost without it.

I can't believe that this crazy thread has lasted for 8 pages and still there have been no firm decisions made about this seemingly crappy product.

 

[Rreyes097]

It works fairly well. Just getting the gold out of the solution is where it's really difficult. And according to the creator it's a waste of time if it's only 1 to 2 grams of gold. I still haven't been able to get my gold. Any one got any advice? And how is the electric method done?

 

[g_axelsson]

Interesting definition of "fairly well"... This aircraft works fairly well, if we just could find out how the landing gear works we would be able to land. :lol:

I'm not impressed by the seller, if he can't advice you on how to recover 2g of gold would he be able to do it if it was 200g of gold? As a customer, if a test run with 2g gold is a bust, I would never add more gold to it until I'm positive I could get it back.

Göran

 

[anachronism]

Goran

Given that the product is designed for mining, I can actually understand the seller's perspective, 1g to 2g IS a complete waste of time in the context of what the product is designed for. They sell this stuff in multiple tonne loads. That given, Dean and Chris' respective points are the ones that come to the fore when looking at this product.

Rreyes there are a number of perfectly effective gold leaches and recovery processes that dissolve the gold readily. For many of them, actually getting your hands on the gold without either investment (often heavy investment I might add) into equipment or extraction methods such as resins is a completely different matter.

 

[goldsilverpro]

If you can't get your gold out of it, then it doesn't work at all.

 

[anachronism]

If you can't get your gold out of it, then it doesn't work at all.

Yeah- I guess I was approaching it from the "glass half full" angle

You know the approach that the gold that used to be on that component is now off the component and in one place so it's a win!!

 

[goldsilverpro]

Technic sells a cyanide gold stripper that doesn't allow copper to be attacked at all. It strips gold quickly and thoroughly. It contains a lead (I think) complex that somehow prevents the copper attack. There are patents on it - I think they are by ACR (American Chemical and Refining?). The problem is that you can't get the gold out by zincing, electrowinning, or any other traditional method - I have tried most of these methods with no success. It requires treatment with sodium hydrosulfite (dithionite), which is tricky. I don't remember this ever being discussed on the forum. I do remember a good thorough discussion on it at sciencemadness.org several years ago. I would probably search for sodium hydrosulfite gold on that site.

The problems you're having with recovery from this eco-goldex crap sound familiar and the formulation may be similar to the Technic product. This is only a guess, however.

 

[patnor1011]

My advice to anyone who is struggling to reclaim values from this leach will be to try all possible variants they are available, one at a time. Say that you have 1l of pregnant leach. Take say 1/10th of it and do some experiments. Do not put all your eggs in one basket. I mentioned it several times, leach is good to experiment with but one can move to bigger lots only when they do have a working and tried system or process.
While I know leach is working rather well under some specific conditions this thread at least gave people knowledge and extra processes which can be used. Like using straight ferrocyanide instead of this particular leach we discuss here.

I am with Goran, if you cant get it work then it will not work for you it is that simple. Some people are struggling with various processes whole section of forum is filled with threads where people ask for help with even trivial basic things. PM recovery is so complex people learn new things their whole life and while some may be easy to learn others will be too difficult or too complicated to get it right. It all boils down to little details, small variation or deviation from a process may present roadblock which is hard to overcome.

 

[M187g]

Hello,
Sorry about my horrible English.
I read the hole thread about eco goldex e series.
Why i cant find nothing about the electrowinning method by eco goldex???
Would it work with the pregnant solution ?
Thanks
M187g

 

[Deano]

The greatest problem with the Eco-goldex leach is the quantity of metals dissolved by the leach components and the oxidisers associated with them.

The only gold complexes which will not load onto activated carbon in entirety are those with neutral or positive charges.

If you have used one of the Eco-goldex leaches and the dissolved gold will not load onto activated carbon then you certainly do not have cyanide present in the leach

All gold complexes will be reduced by electrowinning.

The greatest problem with electrowinning the Eco-goldex leaches is that the electrowin product will contain pretty well most of the other metals dissolved by the leach.

You end up with a little bit of gold co-deposited with a lot of base metals.

Because the leaches contain oxidisers you will also have to run run much higher over-currents than you would expect to.

In summary; yes you will be able to electrowin gold from the leach solutions but the resultant cathode deposit will require further processing.

The cell requirements will be more expensive and the further processing will be more time consuming and expensive.

If this is the way you want to process your gold then I have little sympathy for your poor choice of leachants.


Deano

 

[Patry0t]

here is an update video from the maker of Eco-goldex:

https://www.youtube.com/watch?v=iwZwqv1Jq18&feature=youtu.be

 

[Iggy-poo]

here is an update video from the maker of Eco-goldex:

https://www.youtube.com/watch?v=iwZwqv1Jq18&feature=youtu.be

All of the excess chemicals used is going to cut into profits, besides generating a lot of waste.

Has anyone tried the activated Carbon available for use in aquariums. For someone experimenting with small quantities of material, it seems like a commonly available reagent.

 

[Patry0t]

guys what do you think about this one:

https://www.youtube.com/watch?v=shjRjTUdAXc&t=0s

It says its cyanide free.

 

[g_axelsson]

Dead giveaway in the video... "patented", took me two minutes to find:
https://patents.justia.com/patent/9090985
https://patents.justia.com/patent/20120292201

But as it is in patent-speach, it's a bit hard to find any solid details. The text covers a number of different chemicals that can be used for stripping and I only took a brief look at it. Basically it is an electrolytic assisted method.

Göran

 

[tasgold]

Things which make me wonder are;

1 Why would anybody use a leach formulation containing cyanide amongst a raft of other chemicals when they can just use a straight cyanide or ferrocyanide leach at a cheaper price and with less side reactions.

2 Why would anybody accept the marketing blurb as gospel without at least trying activated carbon.

The bond strength between gold and cyanide is multiple orders of magnitude greater than the bond strength between gold and any other ligand in these formulations. This means that any gold solubilised by a leach containing cyanide amongst other ligands will have the gold in the cyanide complexed form.

Other ligands may leach the gold faster than cyanide but the presence of cyanide will ensure that the final complexed form of the gold will be as the cyanide form.

The presence of chemical oxidants and multiple ligands in the leach formulations will ensure that not only will these formulations leach many more base metals than straight air oxygenated cyanide leaches but that there will be major problems in the recovery stage.

Often the claim of the gold not adsorbing on activated carbon is made either to cover the fact that there is no cyanide present (eg thiourea leach) or that the carbon is swamped with both dissolved base metal complexes and leach components.

If you have some great desire to use these leach types at least try activated carbon for yourself and get some real numbers on the gold adsorption.

Run the leach solution very slowly through a column of carbon and use AAS to see what actually happens to the gold.

My suspicion is that the gold will load onto the carbon but it will require ashing of the carbon and aqua regia digest of the ash to recover the gold.

If the gold does not load onto the carbon it is fair proof that there is no free cyanide present in the leach.

Keep in mind that thiourea is a listed carcinogen.

Deano

which form of ferrocyanide is best for gold recovery, with carbon loading for recovery??

 

[Deano]

The form of the ferrocyanide does not matter provided you do not use ammonium ferrocyanide which will evolve large quantities of ammonia at pH 11 or ferro/ferri ferrocyanides which will form the insoluble Prussian blue dye .

Buy it by price, potassium or sodium are both fine.

Deano

 

[solarsmith]

Eco-goldex O series for ore.
i got 10 kilos last week and am now trying to learn all the particulars about how to use it before I actually use it on my ore. The instructions come as a pdf in an e mail when the order is shipped. When I read the section on (gold recovery from leaching solution ) I saw a big problem. It reads .'' gold recovery from pregnant solution can be achieved through activated carbon (resin) adsorption column, zinc powder /strips methods.'' Thats it! All other instructions pertain to the leaching . No wonder every one is having recovery problems. I have made a step by step list of instructions that use a zink strip recovery process.
I have had it reviewed by ecogoldex and will include it with this post. I have not used it yet so I can not speak to how well it will work for me. It still has a few things I would like to add to it but it is a important notes and instructions/guide and has been reviewed buy eco goldex. Hope this gives more answers than questions.

1----make a aqueous solution from  water and lime or na(OH)2   to make the ph 10 or higher.  target 10.5 to 11.5   not over 12. let set for 2 hrs.

2----for duration of leaching keep ph  10 to 12

3 ---- for common gold ore   add 800 to 1500 grams per ton of water  

4 ----  for sulfide and complex ores  add 2000 to 4000 grams per ton of water.

5 ---- or 1 gram to 2 grams per lb of water.   (8.5 to 17) grams per gallon)

6 ---  temp of leach  15 degree centigrade or higher (60f)

7  ---  add  leach powder to maintain concentration for duration of leach see pdf instructions for info on this

8 ----  maintain temp and ph for duration of leach.   

9 ---- agitate for duration of leach.

10---  leach 1 to 48 hrs.

11---   filter solution  and circulate through zinc turnings 

12---   no ph adjust keep it  10.5 to 11.5

13---  Cement gold and pgms with zinc  turnings (if zinc not black after 12 hrs drop is complete)

14 --- dissolve  zinc strips in  diluted Hcl. 15%

15--- filter residue  (blacks)  wash 2x with water

15--- clean with diluted Hno3 heat (simmer) to make sponge.   Can add filter to the acid for this clean up.trim off extra filter material first.

16 ---    pulp or ore density can be as high as 50% solids by weight but 40% is normal. to maximize ore density a( marsh funnel) test may be in order.

note --- after leaching a vacuum process of the leach to remove air can be done but not required (mostly done by larger operators)

note------- e chem only not for ore process
"Chemical A: Citric Acid, CAS No: 77-92-9
Chemical B: Ammonia Fluoride, CAS No: 12125-01-8
Chemical C: Magnesium Sulfate, CAS No: 7487-88-9"

note-----  e chem only not for ore pocess
The addition of ether NH3 - or - chemicals A/B/C is done AFTER leaching the gold & BEFORE cementing the gold !

note------


























9

 

[ZamGold]

How much ammonia should I add to the leach solution before adding the zinc?