# recovering gold from sodium cyanide.?



## Samjane (Oct 28, 2016)

Help, Hello all this is my first post
We recover gold from scrap electronics by submersion into sodium cyanide solution.
we then send away to a subcontractor refiner the solution loaded with gold for recovery.
I'm interested in the methods used to recover the gold from the solution, I've looked on line without any joy as I don't know the correct technical terms to look for thanks in advance for any help regards Sam


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## jason_recliner (Oct 28, 2016)

I've never handled cyanide. But here's a search I made for you. It's yours, for free.
http://goldrefiningforum.com/phpBB3/search.php?keywords=sodium+cyanide+drop+gold+zinc


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## goldsilverpro (Oct 28, 2016)

What oxidizer are you using along with the sodium cyanide? Hydrogen peroxide? Ludigol (m-NBSS)? What? Are you using a proprietary stripper? If so, what brand?


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## anachronism (Oct 28, 2016)

Sam

I can give you some help with that, using some processes I use already. I have dropped you a PM.

Jon


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## FrugalRefiner (Oct 28, 2016)

We'd really prefer you share your advice on the open forum so that others may benefit and we can confirm your process. Providing refining advice via PM has always been discouraged.

Dave


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## anachronism (Oct 28, 2016)

Surely that depends on whether proprietary and commercially developed processes are involved Dave. I trust you take a different view on that basis?

Edit: 

Given the above, you have two main options. One is to use an electrowin cell, the other is to use a carbon tower setup. The outlines of these have been described very eloquently by Deano. I'm not entirely sure how many people on here have taken the frameworks mentioned and developed them into working processes but I am happy to provide some pointers. 

You can also use a recirculating leach system which constantly strips the gold whilst recovering it using one of the methods mentioned above, thereby retaining your original working leach solution whilst recovering the gold on an ongoing basis. This may be a suitable vehicle for what you are trying to achieve, with the benefit of not employing a third party to recover your values. 

I hope that helps.

Jon


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## Lino1406 (Nov 4, 2016)

There are several answers. For example, Zn powder, Al powder/foil... ref:"30 and more recovery procedures"


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## jeneje (Nov 4, 2016)

FrugalRefiner said:


> We'd really prefer you share your advice on the open forum so that others may benefit and we can confirm your process. Providing refining advice via PM has always been discouraged.
> 
> Dave


It is not so much for others to benefit from as it is to check such a process to make sure correct advice is given. Cyanide in any form is extremely dangerous and should be handled correctly. This forum has many, many members that can give the right advice without using PM's. 

Dave, you are right this type of advice needs to be aired in open forum.

Ken


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## anachronism (Nov 4, 2016)

They've already processed the base material in cyanide. That's pretty reasonable to assume Ken that, as they do it for a business in the UK, they understand the risks given the strict legislation we are governed by. 

They are asking how to recover the values from the pregnant solution. This is a completely different scenario.


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## jeneje (Nov 5, 2016)

anachronism said:


> They've already processed the base material in cyanide. That's pretty reasonable to assume Ken that, as they do it for a business in the UK, they understand the risks given the strict legislation we are governed by.
> 
> They are asking how to recover the values from the pregnant solution. This is a completely different scenario.


I understand what they are asking. My point here is, if they fully understood the process they were using --they would not need to ask how to recover the Au from it. 

So, with this said, the OP needs help. This help needs to come from someone who really understands the process from start to finish and is willing to post about it here on this thread to get him/her through it safely. That is all i am saying. PM-ing someone is like saying look i will help but, I don't want anybody to know. That tells me you *DO NOT* fully understand the process yourself. 

Ken


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## anachronism (Nov 5, 2016)

So sending someone a PM means I don't understand it. OK.


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## jeneje (Nov 5, 2016)

anachronism said:


> So sending someone a PM means I don't understand it. OK.


Yep, pretty much, that is what It means. If you understand the process, post the procedure so it can be checked by the chemist here. 

Ken


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## anachronism (Nov 5, 2016)

If you're talking about the cell and the carbon. I've already made posts about them. I must admit that not liking the tone of where this is going Ken.


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## jeneje (Nov 5, 2016)

anachronism said:


> If you're talking about the cell and the carbon. I've already made posts about them. I must admit that not liking the tone of where this is going Ken.


I don't care weather you like it or not Jon. The truth is, you should not be offering anybody advice by PM's when they post a question on open forum asking for help. So, to be perfectly clear here, post the procedure that is needed to help the OP, or quit posting this BS trying to pick an argument.

Ken


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## anachronism (Nov 5, 2016)

I'm not trying to pick an argument here Ken, you're the one being combative and calling me out. I'm not biting any further because somehow I'll end up being the antagonist regardless of what I say or do. 

Jon


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## jeneje (Nov 5, 2016)

I hope the OP will wait for one of the moderators or chemist's here to post the proper procedure before trying to finish the extraction process so he/she want get hurt or worse killed.

anyway, good luck and be safe.

Ken


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## nickvc (Nov 5, 2016)

To be fair I can see Kens point of view as it's always good to have processes posted for critical review, but I know Jon knows what he is talking about, much of the information has been posted by Deano,it's just few have bothered to follow his advice or learn from a true master of the art of recovery.
So let's stop the bickering and let the true purpose of the forum carry on, refiners helping one another, the use of cyanide is not a recommended process as it's hard to obtain, with good reason, and it's use is generally only for professional refiners/ recoverers who have the needed safety procedures and equipment plus the licences needed.
I can help and so can others if I or they feel the OP is in the right position to follow what is advised and has the necessary knowledge to do so safely, certain cyanide strippers are hard to impossible to get to precipitate, assays and patience are always needed.


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## 4metals (Nov 5, 2016)

We have been very fortunate on this forum that Deano from Downunder has been generous enough to post from his vast life experiences concerning leaching of ores (and e-scrap) and recovering the gold from the leach process. 

Often this involves cyanide. Maybe it is time for us to reconsider cyanide as a leach for e-waste and discuss it's safe handling and waste treatment. I know I am not alone amongst the professional refiners on this forum in realizing the benefits of cyanide for this application but we have hesitated because of it's inherent danger when mishandled. It is however a real and viable solution for the materials a lot of our members refine. So for one, I think this warrants an open and thorough discussion to re-visit our hesitation to discuss cyanide. 

But this goes deeper than cyanide and beyond the writings of this forum and the bickering about ancient history will stop immediately. It has no place on *this* forum. 

I do know that Jon has taken the time to painstakingly follow Deano's threads and apply it to e-waste and extract the gold using methods presented in threads that Deano has posted. Because of this, and his experience working this system, he is quite qualified to comment on removing the gold from cyanide solutions. 

A brief summary of the methodology Jon is using, while he has posted it before, would be useful here to get this thread back on track.


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## Barren Realms 007 (Nov 6, 2016)

4metals said:


> We have been very fortunate on this forum that Deano from Downunder has been generous enough to post from his vast life experiences concerning leaching of ores (and e-scrap) and recovering the gold from the leach process.
> 
> Often this involves cyanide. Maybe it is time for us to reconsider cyanide as a leach for e-waste and discuss it's safe handling and waste treatment. I know I am not alone amongst the professional refiners on this forum in realizing the benefits of cyanide for this application but we have hesitated because of it's inherent danger when mishandled. It is however a real and viable solution for the materials a lot of our members refine. So for one, I think this warrants an open and thorough discussion to re-visit our hesitation to discuss cyanide.
> 
> ...




I would have to agree with you on the fact that it might be time to bring this more out into the open for discussion. I see a couple of problems or concerns about doing this. 

#1 The language barrier and making sure that the process is understood correctly when it is translated into another language. 

#2 Someone half ass reading the description of the process and not following it the correct way. 

#3 Some doing like we see a lot of posts where a member has a number of different containers and not knowing what is in each one and they just go pouring everything together into one container.

#4 Making sure you have the proper facility and equipment to do this process

#5 Follow the safety measures.

#6 Be prepared if you screw up or something happens that you did not plan on happening and you walk into a dangerous situation. Always stay aware of your surroundings inside and outside.


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## 4metals (Nov 6, 2016)

Barren,

While I agree with all 6 of your precursors for discussing cyanide, they are actually also precursors for handling concentrated acids used in aqua regia refining and that is discussed openly. 

I cannot see letting members who practice good refining practices and read and familiarize themselves with procedures before jumping in be limited in their refining knowledge by those who are careless and sloppy. 

My biggest concern is the spent solutions being mishandled.


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## Lino1406 (Nov 7, 2016)

My position is that if you already have it, meaning you are a chemist and have the adequate approvals, you can deal with it. Otherwise do not enter into it.


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## anachronism (Nov 7, 2016)

To be perfectly Frank, I think that since people are beginning to throw eco-goldex around like sugar without realising exactly that they are playing with this IS the time to have an open and informed discussion.


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## g_axelsson (Nov 7, 2016)

I'm all for an open discussion. As stated above, when people doesn't understand what they are doing they will experiment. Better to have an exhaustive discussion with security procedures and how to destroy the cyanide after the gold is recovered.

Göran


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## upcyclist (Nov 7, 2016)

I think a new approach might make sense, otherwise cyanide might appear to be some sort of Forbidden Fruit.

I think a lot of the concerns from Barren's 6 items can be at least mitigated with this one: 

7. Take responsibility for your actions.

If we speak clearly about the dangers of cyanide, at least some of that should leak through translation software (or skills). Ditto for people who skim these threads. I know this is a personal stance (I'm not trying to convince others), but if I hand someone a knife after telling them it's sharp and know they understand what can happen with sharp things, and they cut themselves or someone else, that's on them. There's some nuance to that, but I don't think this is the right place to get into that here.

We deal with a number of dangerous substances here--both materially and in our discussions, and I think we do a good job of warning others. These warnings are why I still don't mess with cyanide unless I know it's actually the best tool for the job. Those warnings are also why all of my PGMs are still sitting in the bottom of my stockpot. Heck, it's part of the reason I haven't even set up an electrolytic cell yet.


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## anachronism (Nov 7, 2016)

Agreed

I'd really welcome the discussion as there are certain parts of the chemistry of the ferrocyanide that I would like to be 100% sure on. I think I'm pretty much "there" if that makes sense with regards to the UV breaking the bond between the 6 CN- ions around the Fe atom and thereby freeing them for the leach process however certain things still could use some clarity. For example the exact applicational differences between the Ferri and Ferro cyanides beyond the chemical formulae.

Did you want to make a thread Goran then we can all pitch in? 

Jon


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## 4metals (Nov 7, 2016)

I think all cyanides should be discussed. However in the US (and likely the UK) Cyanide sets off alarms with environmental agencies and the Ferrocyanides do not, for that simple reason a distinction has value here. 

I know the metal finishing forums have discussed cyanide solutions for years. Refining, as does any chemical process, requires some responsibility to be taken by the user. It is our responsibility to post and critique posts, to get the proper information out there to our members.


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## g_axelsson (Nov 7, 2016)

What do you all think about starting a major thread for cyanide where we give references to resources and other major threads. Then we start a number of threads for different aspects of the cyanide process.

I suggest the following threads :

- Cyanide main thread : Contains references to documents and other major threads with a first post edited to add links when something new appears.

And the following minor threads :
- Cyanide destruction
- Cyanide equipment
- Cyanide leaching
- Cyanide legality
- Cyanide safety
- Cyanide storage
- Cyanide toxicity
- Cyanide waste
- Recovery of metals from cyanide solution

Anything missing or to remove?

This is a huge area and there are several books written on the subject. For example the books at the internet archive.
https://archive.org/search.php?query=subject%3A%22Cyanide+process%22
And this document from the EPA about cyanide handling in plating business.
https://cfpub.epa.gov/si/si_public_record_Report.cfm?dirEntryID=65824

Göran


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## anachronism (Nov 7, 2016)

Safety and toxicity could be combined. 
Waste and destruction too.

Other than that, it looks pretty good.


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## jeneje (Nov 7, 2016)

Members, i want to clarify my position in this thread. It has nothing to do with Cyanide itself, but the giving of advice by PM. I can't speak for other Nations or States in the US, but here in Tennessee if you give advice to a person and it causes injury or death of that person, and if the law can prove it you can be charged with a crime. 

This is a true story, last Friday night my friend's boyfriend and his running buddy was out drinking. By 2:00 AM they were ripped, they did make it to the house however, John told my friend to take his buddy home, she told him where to go and went to bed.

Around 3:00 AM John decided to take his buddy home. They got stopped by the law and he got charged with DUI and his buddy for( PD) public drunkenness. The law took the car and locked them up as one would expect. Well, the car they drive belongs to my friend and it was registered in her name. althought she was not with them, nor was she drinking. The next morning the County Sheriff came to her home and arrested her for drunk driving. 

The point here is this, the forum has disclaimers to protect members and the owner from being liable for information posted in open forum. Giving advice to other members by PM's may or may not be covered by the disclaimer here. 

It is up to each member whether they choose to take such a chance and it was NOT my place to interfere in those members activities. Jon, I apologize for my comments to you. My ONLY concern was the health and welfare of the OP, as this was his first post.

Ken


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## FrugalRefiner (Nov 7, 2016)

I'd suggest adding a section on potassium ferrocyanide vs. eco-goldex. "Eco-goldex" sounds like an ecologically safe process, but it's just a pricey ferrocyanide leach.

Most members probably can't get their hands on sodium or potassium cyanide. Ferrocyanide is a workaround like some of the other processes we discuss.

Dave


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## upcyclist (Nov 7, 2016)

g_axelsson said:


> What do you all think about starting a major thread for cyanide where we give references to resources and other major threads. Then we start a number of threads for different aspects of the cyanide process.
> 
> I suggest the following threads :
> 
> ...


Question for ya Göran: What do you mean when you say _threads_? Are you talking about creating and maintaining posts? Subtopics? What you posted above is a great outline for organization, but I think they would work better as sections of a wiki page (coughGRWcough) than threads. Once you're in a forum, there really is no organization except for the Topics & Subtopics. People will post their thoughts/ideas/problems, and we'll discuss. 

Even if we did a subtopic (Processes: Chemical Processes: Cyanide), so many posts would fall outside of it because often the questioner ("What do I do with these pins?") doesn't know that one possible answer is a cyanide process. Such a post would continue with the pros & cons of cyanide vs. other methods.

Now, if we're talking a master thread/post in The Library, _that _could work well. That would be a moderator-curated thread (or set of threads as you proposed above). 

Or maybe I'm just not getting your groove?


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## anachronism (Nov 7, 2016)

Ken

Apology accepted. Let's turn this whole thing into a positive. 

Jon


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## g_axelsson (Nov 7, 2016)

Ahemmm... what a coincidence that there is a similar list on http://goldrefiningwiki.com/mediawiki/index.php/Cyanide :mrgreen: 

With a thread I mean like this thread. No new sections or subsections are needed. By starting each thread with an "intro and index"-post we can always go back and edit it to put links in to the other threads. That way we only need to keep track of the main thread. It can be put in the library when it is complete.

Göran


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## nickvc (Nov 8, 2016)

I personally feel that as this ferrocyanide and its various forms is fairly easily available that we would be remiss not to cover the safety aspects and also the safe and legal disposal of it, as I have stated many times we are under the spotlight of government agencies so facing the potential dangers to the users, other people and animals and the environment is almost mandatory now, I am also fairly certain that this material will become a controlled substance within a fairly short time especially if we have any disasters or deaths, but in the meantime we need to be seen to be doing our utmost to protect where and when we can.


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## kurtak (Nov 10, 2016)

g_axelsson said:


> What do you all think about starting a major thread for cyanide where we give references to resources and other major threads. Then we start a number of threads for different aspects of the cyanide process.
> 
> I suggest the following threads :
> 
> ...



Absolutely - considering the safety issue of working with cyanide & the fact that there has been some discussion of it already - but - much of that discussion scattered here & there with "bits" of info "here & there" --- I think (as others have also voiced) that a thread specific to cyanide is the prudent thing to do

Whether as A thread the covers all the above suggestions - or - broke into threads pertaining to each aspect doesn't really matter --- the important thing is that we cover all aspects as a matter of prudence to provide complete information on working with cyanide in away that it can be referenced &/or research as a "complete" information 

Threads - as a result of on going discussion tend to get cluttered (as has this one) so A thread & or multiple threads could then be edited &/or linked for quick reference through the Library as a "Library Topic"

I can't open the discussion as I have never worked with it - so will have to leave to those that have - I am certainly interested though

Kurt


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## 4metals (Nov 10, 2016)

I think the first post in the series should be to open a few eyes and help focus on safety and that would be Cyanide and why it can kill you. And then we can explain the path of toxicity and some safety, and then get into using it for recovery. 

I will start a thread when I get home this weekend.


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## autumnwillow (Nov 10, 2016)

Make the cyanide part of the forum private.
Imagine it being public, a mess, just a mess and lives being at stake. If the cyanide forum should be opened to public it should be on how to handle it and how to treat the wastes. Not on how to use it. They need to know well first how to handle and dispose of it first.

Not sure but I think a member should pay for a test, done live (maybe thru chat?) and answer a few cyanide related questions. If he passes then off he can access the subforum. If not he better do his research first as to how to handle cyanide. It is fairly available in textbooks and search engines.

People who work with cyanide should be very responsible.


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## anachronism (Nov 10, 2016)

People seem to have this un-reasoned fear of cyanide, whilst they are happy to work around hot concentrated sulphuric acid, or deal with nitric acid and AR without fume hoods. Make no mistake- lives are at risk with all the other processes we use and people should not lose sight of that. 

I agree that if people are stupid enough to ignore the safety factors involved with the above, then they will avoid them with cyanide. But what do we do? 

Keeping people in ignorance has never worked out well in any historical context.


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## autumnwillow (Nov 10, 2016)

Nitric, AR and sulfuric will injure you or kill you slowly.

Cyanide poisoning will kill you quick. And not all hospitals are equipped with its antidote.

Do not compare these common acids used for refining with cyanide.


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## patnor1011 (Nov 10, 2016)

autumnwillow said:


> Nitric, AR and sulfuric will injure you or kill you slowly.
> 
> Cyanide poisoning will kill you quick. And not all hospitals are equipped with its antidote.
> 
> Do not compare these common acids used for refining with cyanide.



You may be surprised to hear that but cyanide is more common in recovery&refining than what you call "common acids used for refining".
Slowly or quick (killing) is not an argument.
But I do agree - If you're afraid of wolves, don't go to the woods.


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## anachronism (Nov 10, 2016)

autumnwillow said:


> Nitric, AR and sulfuric will injure you or kill you slowly.
> 
> Cyanide poisoning will kill you quick. And not all hospitals are equipped with its antidote.
> 
> Do not compare these common acids used for refining with cyanide.



I disagree - I'm not downplaying the dangers of cyanide, rather upgrading the dangers of the other acids and reagents. Not enough respect is given to the dangers of the common acids. We should treat the others with the same respect as cyanide and this doesn't happen enough.


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## autumnwillow (Nov 10, 2016)

patnor1011 said:


> You may be surprised to hear that but cyanide is more common in recovery&refining than what you call "common acids used for refining".
> Slowly or quick (killing) is not an argument.
> But I do agree - If you're afraid of wolves, don't go to the woods.



The context of common is this forum, not outside this forum.
I am not arguing anything in the statement I made.
Your third line does not seem to make any sense. Does one have to be brave in order to deal with cyanide? I think that person should be knowledgeable not brave.

I am sorry I think I am tired but I cannot understand your statements.


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## 4metals (Nov 10, 2016)

> Make the cyanide part of the forum private.



This could cause more problems than it is worth. How will we decide who to let in? How do you prove you are careful enough to be let in? Everyone assumes they are qualified and I believe the forum has more responsibility if we choose a member to join the private club and he or she ends up getting hurt.

Refining with chemicals or smelting is a grown up sport, the forum has made disclaimers about the dangers and every chemical or red hot furnace carries unique threats if used improperly. We expect our members to follow directions and we strive to correct any members posing questions if they are heading in the wrong direction. 

In the end I think it is wiser to broach the cyanide subject with facts and good procedures than to bury our heads in the sand and make believe it doesn't exist. Cyanide is real, cyanide is widely used for refining, and we have grown enough as a forum to discuss the topic in a way that our members can use the information in a safe and environmentally sound way to process their precious metals.


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## goldsilverpro (Nov 10, 2016)

4metals said:


> > Make the cyanide part of the forum private.
> 
> 
> 
> ...


I totally agree with 4metals.


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## autumnwillow (Nov 10, 2016)

The very bad thing about cyanide is its fumes are not visible to the naked eye. Unlike acids where you could see or smell them and have time to go away. Cyanide is just fast.

An ORP meter and pH meter should be done on the test.

Whatever you guys decide on to I'll help with my experience on cyanide.


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## anachronism (Nov 10, 2016)

If you're running cyanide at pH 11 you're not going to have clouds of HCN coming off the solution.


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## goldsilverpro (Nov 10, 2016)

autumnwillow said:


> The very bad thing about cyanide is its fumes are not visible to the naked eye. Unlike acids where you could see or smell them and have time to go away. Cyanide is just fast.
> 
> An ORP meter and pH meter should be done on the test.
> 
> Whatever you guys decide on to I'll help with my experience on cyanide.


In general, the fumes are not as hazardous as most acid fumes, except those generated (HCN) by combining cyanide and any acid or from solutions with too low a pH. Fumes (mainly hot fumes) off of an alkaline cyanide solution can, however, produce a very annoying skin irritation called cyanide itch. I covered a lot of this is this post:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=24567&p=259896&hilit=cyanide+itch#p259896

I would guess that 4metals and I have much more experience working with cyanide, hands-on, than anyone else on the forum. I would guess that I worked with it daily for a period of 25 years. Sometimes with huge quantities, like 1000's of gallons. To me, it makes it safer to talk about it rather than to keep it a secret. When we only allow the elite to read about it, the ignorant or those not allowed to read about it could mess with it and end up dying.

When you know and obey the rules - don't eat it, don't drink it, don't swim in it, don't smoke, eat, or drink around it, or don't add acid to it - it can be far safer than concentrated sulfuric, strong lye solutions, or aqua regia.

For several years In the late 60's, I spent at least a day or two a week in electroplating shops in L.A., troubleshooting plating problems. At that time, there were many 100's of plating shops in L.A. Every shop had at least one (and usually, several) tank filled with a cyanide solution. Some held 1000's of gallons and as much as 1/2 pound of cyanide salts per gallon. I never heard of anyone being hurt or poisoned from cyanide in those shops. They were taught the basic safety rules and adhered to them. At the same time, there were many acid accidents where people were severely injured.


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## 4metals (Nov 10, 2016)

> I never heard of anyone being hurt or poisoned from cyanide in those shops. They were taught the basic safety rules and adhered to them.



For years, if I couldn't find an experienced refiner to hire (which is difficult anyway to find, even today) I would advertise for workers with electroplating experience and train them to refine. I always found them to be well trained to be safe around chemicals, that is a good foundation to teach someone to refine.


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## Shark (Nov 10, 2016)

My opinion from the aspect of a person who knows virtually nothing about cyanide, other than it can kill you. 

Many who want to know how to use cyanide from a cost or efficiency stand point have two primary choices. They can go to someone (or a group of people) who are knowledgeable in it's use, or they can just continue to experiment on their own (as seen in the Eco-Goldex thread and other venue's like youtube). I have no plans at the moment to use any form of cyanide and I *can* see where it's use could be the preferred method for certain materials. In a month or a year, I might be wanting to try it so if I start studying now, I should be ahead of the curve when I am ready. Last year if some one told me I would be melting copper and running a copper cell I would not have took them serious, but I still done some studying on the subject. When 4metals started the post on smelting and the copper cell I was ready to give it a try, but I knew enough by then to be able to follow most of what he was saying. A few question and a bit more reading and I have been fairly happy with the results.

I would much prefer to learn from the senior members here than youtube. I don't much mind experimenting with things, but somethings are just easier, safer and quicker to learn with good help. If this thread gets started I will be reading very closely just in case I need to use the information sometime down the road.


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## anachronism (Nov 10, 2016)

4metals said:


> A brief summary of the methodology Jon is using, while he has posted it before, would be useful here to get this thread back on track.



4metals. 

My apologies I missed this part of your post earlier.

In the interests of getting this thread back on track.

Stripping the gold from a cyanide leach. 

The first option is zinc. This is all well and good until you have a leach accelerator and/or excess CN- and oxidant in the solution. At this point you can end up in a loop whereby your gold precipitates out and is redissolved into solution in a similar manner to having Nitric present in an AR solution. If you are using a CN leach with merely air as the oxidant then zinc works extremely well but many leaches contain H2O2 or MBNSS or other proprietory additions. 

Second option is electrowin. You are passing your leach liquor through a cell which is stripping the metals from the liquor onto the carbon cathode. The advantages are that your liquor is then devoid of metals and can be processed back into your original leach with minimal degradation of the CN content of the leach. The cathode which contains the metals can be processed in AR and reused. The down side is the expense of the rectifier and electrowin cell itself but overall it is the most cost effective way of doing this. 

Third option is activated carbon. You load the carbon with the metals in the leach and again pass the liquor back into the leach tank to carry on stripping metal. The upside again is that you return a stripped liquor which is reusable. The downside is that you then have to ash the carbon in a suitable furnace and process the ash. Your costs are activated carbon, and a good furnace. 

Options two and three will both work using oxidants and accelerators in the leach. It's all a trade off you just have to pick the best overall solution to suit your budget and your base material. 

For ALL the above an AAS is almost essential because you need to know when the tenor of your solution is high, or low respectively. Not to mention that you also need to know when it is completely spent.

I hope that helps in some small way guys. There is a lot more to this and I would be more than happy to contribute to the cyanide section that is planned to provide more clarity. 

Jon


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## autumnwillow (Nov 10, 2016)

I have a small refinery with one staff, I never let him work with cyanide since he makes small mistakes that will not work with cyanide. Small mistakes in cyanide can lead to death. He has five kids so I'm not risking it. I am always the one working with cyanide. I also get those itches even when just working with less than 5L of solution.

Just look at the mess other people make in this forum with acids, imagine that being cyanide. We may not have the time to tell them to stop, they may not have the time to post in the forum to ask what they did wrong.

Maybe I am wrong though, maybe we should give out the information since some members will attempt to do it anyway. And it is already being openly discussed here. A trial could be done to see, if too much mess is being generated then close that forum, if it works then that's good!

When I registered here 5 years ago, after reading so much I told myself that I should just hire a chemist with all these chemicals that I am not familiar with until I decided to study on my own. Being with chemicals is just about knowing what they are, what they can do and how to use them. Everything around us are chemicals.


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## Lino1406 (Nov 11, 2016)

I want to highlight two risks of cyanide:
1.Absorption through wounds of over 1g
2.Heavy than air cyanogene (CN)2 and/or cyanogene chloride (CNCl) with noxious smell, appearing on cyanide oxidation/chlorination


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## muhammad Shahzad (Apr 17, 2018)

Lino1406 said:


> There are several answers. For example, Zn powder, Al powder/foil... ref:"30 and more recovery procedures"


Hi lino

Is there need to extract oxygen from cyanide solution to cementation gold with aluminium foil ?

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## Lino1406 (Apr 17, 2018)

If you mean dissolved oxygen it is negligible


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## muhammad Shahzad (Jun 30, 2018)

Lino1406 said:


> If you mean dissolved oxygen it is negligent


 you mean there is no need to pay attention for oxygen to Cementation gold in cyanide solution

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## Lino1406 (Jun 30, 2018)

The amount of dissolved oxygen is negligible hence the effect on cementation is negligible


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