Non-Chemical NaCN - Pins and fingers

[stoneware]

Game changer, this morning the leach has the color of a decent Ale.

The NaCN has done a fine job of removing the gold from the low grade pins but is struggling with some of the older thicker gold plated fingers.

The decorative spoon had gold plating,also incomplete gold removal.

Using small additions of 3% hydrogen peroxide for my oxygen donor, the leach contains 3 grams NaCN using city tap water.

Sodium Hydroxide used to adjust Ph to 12 before adding the NaCN, a bit on the high side but better to error on the side of caution.

I think the process would be best used in a small tumbler, this would help remove the heavier gold plate and you could omit the use of the hydrogen peroxide.

More images coming later.

Top image is the junk I'm working with, everything you see with the exception of the solder went into the leach.

 

[stoneware]

About a half hour ago added more hydrogen peroxide.

 

[stoneware]

I had an ore sample in a gallon jar that I had left unattended for a week or more then one day I noticed the liquid was gone.

The liquid was a strong solution of sodium hydroxide, just so your aware glass is destroyed by NaOH and this is the reason I'm not using a glass vessel for my NaCN leach.

Sodium hydroxide slowly reacts with glass to form sodium silicate.

 

[orvi]

I had an ore sample in a gallon jar that I had left unattended for a week or more then one day I noticed the liquid was gone.

The liquid was a strong solution of sodium hydroxide, just so your aware glass is destroyed by NaOH and this is the reason I'm not using a glass vessel for my NaCN leach.

Sodium hydroxide slowly reacts with glass to form sodium silicate.

That was some either low silica or junk glass. One week at ambient temperature... I stored 40% hydroxide for months in volumetric flasks and nothing significant happened. Depends on glass composition I think. But you are right, better to be safe than dead

I had always respect when I considered cyanide as option for gold recovery. Thing is, I worked with much more poisonous substances than cyanide. Dimethyl sulfate, azides, hydrogen sulfide, metal carbonyls... But I somehow resisted using CN for leaching gold. In production scale, for research, I did few experiments.

 

[Alondro]

That was some either low silica or junk glass. One week at ambient temperature... I stored 40% hydroxide for months in volumetric flasks and nothing significant happened. Depends on glass composition I think. But you are right, better to be safe than dead

I had always respect when I considered cyanide as option for gold recovery. Thing is, I worked with much more poisonous substances than cyanide. Dimethyl sulfate, azides, hydrogen sulfide, metal carbonyls... But I somehow resisted using CN for leaching gold. In production scale, for research, I did few experiments.

We used to keep 10M NaOH in lab glassware for a year or more, until the solution absorbed too much CO2 from the air after being used many times, and became too contaminated by bicarbonate.

 

[stoneware]

Using heat to deactivate any NaCn residue remaining on the pins, etc. Pot will be covered with a lid.

Looking at the pins you can see that a weak NaCn leach left the nickle plating untouched, on the other hand did not strip the gold from the older gold plated fingers.

 

[stoneware]

Could have been several reasons why the NaCn did not completely removed the Au from the thicker plated material.

Likely impatience on my part or most of the cyanide had been consumed.

I need to purchase a couple of burretts and make some silver nitrate then learn how to do a tritration. This will tell me how much cyanide has been consumed from the initial starting point and wither I need to add more.

Also want to build a small tumbler to keep things agitated.

After the gold was removed from the spoon there was a residue of gold powder which could be rubbed off. Which tells me static solution's are not all that effective.

 

[stoneware]

Question for the experts, what has deposited onto the anode used to destroy the cyanide leach.

An issue I encountered the steel wool became impregnated with foam and it wanted to float. So the exposed area became rather limited.

Over night though the leach is almost crystal clear.

 

[Ultrax]

Cyanide has a perfect selectivity for gold, but its concentration should be very low(!). So to be able to remove all your gold without base metals you just need to use an additional fresh solution. You won't remove all the gold in a limited volume of the solution or with high concentration of cyanide. How much did you place in the leaching vessel? Highly likely that you have added too much cyanide. In this case, on your anode can be a wide variety of undesirable chemicals. Dangerous chemicals.
Moreover, you won't destroy cyanide by this electrolysis - this waste should be treated very carefully. This is a dangerous delusion, if it were so simple cyanidation technologies would not be seeking to replace in the industry due to ecological problems. Use active carbon to precipitate gold from the solution. Best DIY carbon can be taken from fruit stones or coconut shells burned without oxygen and treated with hot (min.120C) steam.

 

[stoneware]

Cyanide has a perfect selectivity for gold, but its concentration should be very low(!). So to be able to remove all your gold without base metals you just need to use an additional fresh solution. You won't remove all the gold in a limited volume of the solution or with high concentration of cyanide. How much did you place in the leaching vessel? Highly likely that you have added too much cyanide. In this case, on your anode can be a wide variety of undesirable chemicals. Dangerous chemicals.
Moreover, you won't destroy cyanide by this electrolysis - this waste should be treated very carefully. This is a dangerous delusion, if it were so simple cyanidation technologies would not be seeking to replace in the industry due to ecological problems. Use active carbon to precipitate gold from the solution. Best DIY carbon can be taken from fruit stones or coconut shells burned without oxygen and treated with hot (min.120C) steam.

What a bunch of rubbish, titrating the cyanide solution will inform you if additional NaCn is required. There's no need to run a fresh leach

Zinc will also cement gold and other elements from the liquor..

 

[Ultrax]

Wow, now I see that you don't need any rubbish advice Especially if you need other elements.

 

[stoneware]

Wow, now I see that you don't need any rubbish advice Especially if you need other elements.

The only advice given was how to make activated carbon, instead of spending time looking for a supply of coconut shells.

I purchased water filters, two of which I'm currently ashing.

If our friend had looked at the material I had recenty leached he would have noticed it's a weak NaCn soloution I'm using as the nickle plating under the gold plate remains untouched.

 

[stoneware]

Wow, now I see that you don't need any rubbish advice Especially if you need other elements.

I've made the mistake of not adding sodium chloride.

Credits, Finishing Forum.

 

[stoneware]

NaCn destruction via Chlorination.

This product contains 65% of available chlorine, a cold solution will retain the active ingredient much longer.

If you first titrate your waste you;ll know how much active NaCn you have to deal with.

Never add these waste soloutions to your stock pot.

 

[Yggdrasil]

You should stop editing and adding images and info in your previous posts.
Editing posts should be done only to correct information that are already there and then give a short notice on what has been done if it is significant.
Your post changes character completely, which means some of the replies may loose its meaning.

Add the images and major changes in new posts so the integrity of the thread is not broken.

 

[stoneware]

You should stop editing and adding images and info in your previous posts.
Editing posts should be done only to correct information that are already there and then give a short notice on what has been done if it is significant.
Your post changes character completely, which means some of the replies may loose its meaning.

Add the images and major changes in new posts so the integrity of the thread is not broken.

The image added is from an enlarged photo in post number #6 which is relevant to this entire thread.

 

[Yggdrasil]

The image added is from an enlarged photo in post number #6 which is relevant to this entire thread.

View attachment 52544

That is correct, but you have changed and added images in the earlier posts.
The image from Finishing has changed, the reaction series was not there from the beginning and these things, they are relevant but when you change the original posts like that, later replies may become out of order or loose their point.

The least you can do, is write a small note with info on what has been edited.

Like this..
Edit: added image or Edit: changed image

 

[orvi]

I will opt for hypochlorite oxidation. Quick and certain. With quantities as you have, it will be easier and more rational than electrolysis - which eventually accomplish the same thing - create chlorine in the mixture, which will kill the cyanide.

 

[stoneware]

Ashed activated carbon.

 

[Ultrax]

I will opt for hypochlorite oxidation. Quick and certain. With quantities as you have, it will be easier and more rational than electrolysis - which eventually accomplish the same thing - create chlorine in the mixture, which will kill the cyanide.

Most metals from electronic wastes are CN-bonded by complex formation. Chlorine won't oxidize ferricyanide, cobalt will resist chlorine oxidation; nickel complex can be oxidized, but requires a much longer contact time. oxidation requires a minimum of 30 minutes of reaction, monitoring of pH and ORP levels, slow mixing, control of ammonia level, and correction of Cl consumption.
I'm certainly sure that wastes after DIY "destruction" will contain significant levels of CN-complexes with heavy metals.