cyanide (Eco-Goldex) & ammonia

[kurtak]

According to the Eco-Goldex PDF instructions you need to add ammonia to the pregnant solution to get the gold to precipitate with zinc --- & they are right

At this point I have only tested it on 250 ml of pregnant solution (in fume hood) first I just added the zinc & "slightly" warmed it - after a couple hours absolutely no reaction with the zinc (& no gold) so I then added about 40 percent (by volume - so about 100 - 120 ml) of house hold ammonia which did precipitate the gold

The reaction was "vary" slow - took about an hour with continuous stirring (on stir hot plate)

So tried another (250 ml) test this morning - instead of house hold ammonia - I used (industrial) 29.5 percent ammonia & only about 20 - 30 ml

Again - "slightly" warmed the solution - then instead of zinc - I used aluminum (foil) & there was a "very" clear (bubbling) reaction & it only took about 10 minutes for the gold to precipitate out

So the question is - besides the ammonia fumes - what other gasses/fumes are being produced in this reaction --- & of course the big question being would HCN production be part of this reaction

Need to know before scaling up - currently have about 8 liters of pregnant Goldex to recover gold from

Kurt

 

[ettran]

hi kurt. I tried the eco-goldex and tried zinc powder and it still sits as before.should I add aluminum foil or ammonia.or should I wait for your results.ed

 

[kurtak]

Ed

With the Eco-Goldex & when using zinc (or aluminum) to recover the gold from solution the gold "will not" cement out with out adding ammonia to the solution

Based on my experiments aluminum is by far a better choice then zinc - a much better choice

Also - although house hold ammonia will work (& it should be ammonia "without" additives) it is again by far better to use industrial grade ammonia --- house hold ammonia only runs "about" 7 percent - the industrial ammonia (mine) is 29.5 percent - consequently when using house hold ammonia you need to use MUCH more which means you are diluting the solution - by MUCH more - which in turn means much more waste in the end

The down side to using high percentage industrial ammonia is you MUST work in a GOOD fume hood or the ammonia fumes will result in your ending up laying passed out on the floor - or worse :!:

Why aluminum instead of zinc :?: --- there are "several" reasons why (based on my experiments)

1) the aluminum is faster then the zinc - much faster

2) with the aluminum you actually see a reaction (fine bubbles) taking place - with the zinc you don't see a reaction --- the result of "seeing" this reaction (with aluminum) is it is also the indicator that tells you when your gold is done cementing out - when you no longer see a reaction - its done cementing the gold (provided you actually had enough ammonia in solution to start with) --- on the other hand - with zinc - because there is no reaction to see - you don't have the indicator to tell you all your gold is cemented out

3) with the aluminum the gold actually "VERY loosely" plates to the aluminum AND it actually looks like gold (very much like the ultra fine gold foils we see with "flash" plated gold) --- with the zinc - the gold cements out as a "fine" black "mud" --- consequently ------------------

4) washing/filtering the cyanide solution out - before going to the acid work part of the process is MUCH easier --- this is (IMO) VERY important as getting the cyanide washed out before going to the acid work is what keeps you from killing yourself with the production of HCN gas - the acid work MUST be done in a GOOD fume hood

5) with zinc - the solution turns "very" cloudy - the result again - like in #2 above - is not being able to see what is going on (is the solution done cementing - or not) --- with the aluminum - the solution "does not" cloud up - instead it shifts color - the color shifts from a lighter amber color to a darker amber color - but because the stays "clear" - you can "see" when the reaction is done indicating the cementing is done

I did not take any pics of my first experiment using zinc - but here are some pics using aluminum - as you can see I shredded some aluminum foil & then slightly crumpled it to give it lots of surface area & distribution area while in the solution during cementing

First pic - the actual cementing "reaction" - though the solution "looks" a bit cloudy - its not - those are the bubbles of the reaction taking place

Second pic the clear solution after cementing & shows how the gold has a fine gold "foil" like deposit on the aluminum

Third pic - gold after using HCl to dissolve the aluminum away - it "looks" like a lot - its not - its "very" fluffy --- "guessing" its about 4 (+/-) grams - this was from about 3000 ml solution

Kurt

 

[kurtak]

Here is a pic of the cloudy solution you end up with after using zinc to cement the gold

Kurt

 

[g_axelsson]

Thanks for sharing the pictures, it really shows a big difference between zinc and aluminium.

Are you planning to refine the gold before melting? I would suspect a bit of aluminium oxide left with the gold. It could also explain why the thin gold holds together so well after the HCl.

Göran

 

[nickvc]

Kurt I always used aluminium foil for a quick pre assay check to see if all the gold was precipitated so I can see why you prefer it, not sure how I picked up that idea it that's what long experience and old age does

 

[Topher_osAUrus]

Seems as if someone finally cracked the eco goldex ppt code.
You da' man Kurt! :G

If I may, where did you get your industrial ammonia?
Every place around me looks to only have the 3-7% and that stuff I will not use anymore, as the additives are a pain.

Thanks in advance

 

[patnor1011]

Seems as if someone finally cracked the eco goldex ppt code.
You da' man Kurt! :G

If I may, where did you get your industrial ammonia?
Every place around me looks to only have the 3-7% and that stuff I will not use anymore, as the additives are a pain.

Thanks in advance

It was cracked quite a while ago. Ammonia was suggested by seller of ecogoldex in pdf he send with purchased product along with video links. Video of full process was also posted on ecogoldex thread few months ago. Kurt used aluminium strips and in the video they used zinc strips. John (ecogoldex seller) do sell zinc strips on ebay. Industrial grade ammonia can be bought on ebay too.
Link to video is here: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=23843&start=120#p261787

 

[Topher_osAUrus]

Must have missed that one.
Thank you pat

 

[frank-20011]

hello,

what's the effect of the NH3 addition?

it couldn't be only the raising of ph because there are enough alkaline substances in the eco-goldex itself (Na2CO3...CaO...NaOH)...so why more alkalies, ore better: why NH3?

regards, Frank!

 

[patnor1011]

It has to be connected with composition of ecogoldex. That is a mix of various ingredients and ammonia make recovery with zinc possible. So either this or carbon.

 

[M187g]

Hello ,
First sorry about my horrible english.
Frank are you from germany?
Did anyone try the electrowinng method from pregnet solution by goldex e?

Gesendet von meinem SM-G800F mit Tapatalk

 

[Rreyes097]

So it's the ammonia used to adjust the pH? If so then to what? And how much aluminum? Then what are you using the HCl for and when?

 

[Maddutch]

Ik had ook een kleine batch zwangere oplossing staan en de oude instructie.
Na veel filmpjes bekeken te hebben en reactie gelezen.
Vond ik iemand die zij dat je loog toe moest voegen
Om een stevige pH 14 te krijgen.
Ik had geen ammonia voor handen.
Ik heb onstoppings korrels toegevoegd deze zijn ook alkalisch.
En ja het neerslaan begon.
Ik had er helaas al wat zink poeder in zitten wat zwarte neerslag geeft
Nog wat alu folie er bij gedaan en ook dat reageerde
Idd gelegen neerslag.
Ik heb dit gespoeld en nu te drogen staan.
Weer iemand wat ik kan verwachten van het zuurbad ?
Zal de hoeveelheid halveren ?
Of pakt goldex niet zo heel veel andere metalen mee ?
Heb voornamelijk pinnen en plating van printplaten gebruikt.

 

[FrugalRefiner]

Maddutch, please translate your comments and questions to English before posting them here. If you translate them one time, it keeps all of our members from having to translate them themselves. Most members will simply not bother, so you may not get many responses.

Dave

 

[acpeacemaker]

So it's the ammonia used to adjust the pH? If so then to what? And how much aluminum? Then what are you using the HCl for and when?

While not familiar with eco-goldex. What are you referring to because hydrochloric acid mixed with sodium cyanide liberates HCN gas.

 

[Rreyes097]

I'm talking about a gold stripping agent known as Eco gold x that I tried. I believe it's a cyanide solution mixture of some sort. I no longer use it.

 

[toonslady62]

I have been accumulating ewaste for a while and I have a container of mixed plated parts. I was going to consider the Eco product. Based on your comments why did you stop using it? Just curious. I am a newbie and am ready to start a small recovery and refin. Any advice would be appreciated. Thanks, Scarlett