Sciencemadness Discussion Board - Gold Recovery Computer Scrap Complete Process

but the gold doesn't have to be sold immediately, one can wait for a more favorable price to sell it. or sell it on ebay to would be investors for an inflated price due to speculation and ebay fee's. cause aint no one gonna let ebay get 13% of the sale cost on gold at market value... they over charge and get what's theirs + some usually.

Pretty long wait for it too double in price? If its a learning thing why buy more than 500g??

[Edited on 14-9-2015 by Little_Ghost_again]

violet sin - 13-9-2015 at 16:57

I surely did not crunch the numbers. I was just saying if it was off a bit, it could be accounted for. if you sell it off in small shot pieces for element collections, that could be another way to inflate the price as well.

I did do a rough calculation on 500g = 1g @ 40$/g and noticed a big deficit. But didn't want to tie numbers into my statement here from my phone without being *sure (science forum and all). But the miss's was using the laptop.. kinda makes the previous statement a poor substitute in lieu of that amount of missing product. But would hold true if it were a few % off, b/c of a cheaper source.

[Edited on 14-9-2015 by violet sin]

kadriver - 13-9-2015 at 17:08

if you work out the figures you have lost money

Hello, please understand that I did not buy the fingers to make a profit, but rather to make a video. It would have taken me several years and hundreds of dollars to buy enough scrap computers to accumulate 500 grams of trimmed fingers.

This is why I don't refine gold from electronic scrap; the yields are too low and you can't make a profit unless you get the scrap for little to nothing.

I am doing some more experiments to try and shorten the time from start to finish. That is why I have all those extra fingers. This video was done in just over 24 hours, start to finish.

I love tinkering and will be producing some more videos of these experiments. Making this video was much fun and I learned some new things that may be incorporated into my refining techniques with other types of scrap.

Thank you for your comments.

kadriver

violet sin - 13-9-2015 at 17:12

Do you currently do runs of good filled or polishing sweeps? Any $ to be made there?

Another interesting way to go is the shor method with ammonium chloride, peroxide and electrolysis. No fumes.

kadriver - 13-9-2015 at 17:27

Do you currently do runs of good filled or polishing sweeps? Any $ to be made there?

Another interesting way to go is the shor method with ammonium chloride, peroxide and electrolysis. No fumes.

Please see my other video entitled "Gold Refining Gold Filled Scrap Complete Process". Or just type in gold refining gold filled scrap in the search block of Yahoo or Google. My video will come up on page one. My user name there is "sreetips"

I have several jeweler a that I work for, not retail jewelry stores, but actual jewelry repairmen. They give me bags of polish sweeps and filings to refine for them. I charge 10% as my fee. If I get 75 grams of pure gold then I get 7.5 grams as my fee and they get 67.5 grams.

I don't give credit for the silver of platinum group metals. I get to keep those as well. It is tough to make a living doing this, that is why I do it as a hobby!

I have never tried shor, don't know anything about it. I was trained on the goldrefiningforum dot com by Harold, lazersteve, GSP, Lou, Butcher and Oz (just to name a few). All my experience is with wet chemical processes with nitric acid as a must.

But I am working on some experiments to eliminate the need for nitric acid. Nitric is expensive and not too easy to get.

Thank you for your comments,
kadriver

kadriver - 13-9-2015 at 17:38

By the way, I am Terrible at chemistry. In this video I am adding bleach (sodium hypochlorite) to the gold foils that are in hydrochloric acid to dissolve the foils. I think that the foils are dissolving from chlorine gas generated by mixing the bleach with the HCl.

Since sodium and chlorine are involved here I also think that there may be some table salt (sodium chloride) in with the resulting chloroauric acid.

Would someone be kind enough to explain what is happening in that beaker when I add the bleach to the gold foils in the HCl?

I need to sign up for some chemistry classes next semester. I'd like to know what's going on at the electron level when I do these reactions.

Thank you,
kadriver

violet sin - 13-9-2015 at 17:44

Shor process = off topic info.
US Patent 5009755 ( http://www.google.com/patents/US5009755 )
Ammonium chloride electrolytic leaching, activated with H2O2. worth a read. The bucket container with dividing ceramic chamber and electrode kit costs like 500$. And you have to buy the chems from the company. Unless you read the patent above. There is also no power supply provided for your investment.

[Edited on 14-9-2015 by violet sin]
From a gold refining forum... http://goldrefiningforum.com/phpBB3/index.php main page.
" . Chlorine is the active ingredient in dissolving the gold in the HCl-Cl reaction. " http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?...

[Edited on 14-9-2015 by violet sin]

kadriver - 13-9-2015 at 17:57

Shoe process
US Patent 5009755 ( http://www.google.com/patents/US5009755 )
Ammonium chloride electrolytic leaching, activated with H2O2. worth a read. The bucket container with dividing ceramic chamber and electrode kit costs like 500$. And you have to buy the chems from the company. Unless you read the patent above. There is also no power supply provided for your investment.

[Edited on 14-9-2015 by violet sin]

Nice. Thank you. Ill look at it carefully. Do you know anyone who has one? I'd like to get some feedback from any users who have operated this apparatus.
kadriver

kadriver - 13-9-2015 at 18:48

[Edited on 14-9-2015 by violet sin]
From a gold refining forum... http://goldrefiningforum.com/phpBB3/index.php main page.
" . Chlorine is the active ingredient in dissolving the gold in the HCl-Cl reaction. " http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?...

[Edited on 14-9-2015 by violet sin]

Chlorine is dissolving the gold (I'm kind of sure that chlorine will dissolve just about any metal). But chlorine is not the only product in this reaction. Im interested in knowing what other compounds are present as contaminants to my pure gold when I precipitate the metal with sodium meta bisulfite.

And what kind of waste compounds will I be dealing with after I add the SMB. These are the kinds of questions I have since I have no chemistry training.

Thank you,
kadriver

aga - 14-9-2015 at 00:07

I'm certainly no expert, however the starting material is a mix of several chemicals, some of which can end up in the solution.

The PCB will be multi-layer FR4 or similar (fibreglass).
The copper is bonded to that with something.
Then there's the Copper and the Gold.
There could be some tin, lead and whatever the solder resist mask is made of etc etc.

Not sure that Chlorine is reacting with the gold directly.
More likely it is a multi-step reaction, with the gold being complexed somehow and then further reacted to end up with chloroauric acid.

Edit:

Oh ! I see you've already tried it, and Chlorine + Hydrochloric acid can dissolve Gold.

Wiki says this reaction happens :-

2 Au + 3 Cl₂ + 2 HCl => 2 HAuCl₄

https://en.wikipedia.org/wiki/Chloroauric_acid

If you're looking to maximise the process/profits then one of the first things to learn in chemistry is stoichimetry, which lets you work out the exact amounts of each chemical you need for a reaction.

[Edited on 14-9-2015 by aga]

deltaH - 14-9-2015 at 03:03

Hi kadriver.

The full picture of what's going on is a little more complex. The production of chlorine gas is, in fact, an unwanted side reaction in this system and could/should potentially be eliminated or at least minimised.

To understand what is going on in the solution, we need to consult the Pourbaix diagrams for gold in chloride media (1) as well as that of chlorine in water (2). Apologies in advance for lazy referencing, I'm battling a nasty flu at the moment.

Gold pourbaix in chloride media.JPG - 39kB

Firstly, take note of the AuCl4- region on the first diagram. It's rather large and goes up even to quite high pH, so you don't need extremely acidic conditions!

Secondly, on the second diagram, note that in acidic media, hypochlorites form hypochlorous acid, a very powerful oxidant indeed, even more so than chlorine (see how it's region lies at a higher potential than the chlorine region on the left?).

So from this diagram you can conclude that the oxidant is probably hypochlorous acid and that hypochlorous acid can decompose to chlorine gas if it doesn't have anything else to oxidise.

Now here's the cool bit, if you're between pH 5-6 in a 1M Cl- solution, you can't form chlorine gas, but can form AuCl4- just fine, even up to very high gold concentrations (1M), which you're far from anyhow.

So I suggest if you want to experiment with an improvement, work in a 1M sodium chloride solution (table salt) which is buffered to pH 5. That way you are not wasting acid or bleach, creating less and less hazardous waste and avoiding the formation of toxic chlorine gas! If you were wondering, the gold in solution would then be in the form of a solution of sodium tetrachloroaurate (III).

Please be careful when selecting a buffer to use. It should not contain ammonia! One possibility is a sodium acetate-acetic acid buffer, since it can be prepared from vinegar and lye, all OTC and cheap!

From reference (3), mixing 70ml 0.2M sodium acetate solution with 30ml 0.2M acetic acid will give a buffer at pH 5. Note 5% commercial vinegar is about 0.8M solution of acetic acid, so you will need to dilute. Don't forget you also need to add sodium chloride to prepare a 1M NaCl solution in that buffer!!!

You could make this in advance and large quantities and potentially have a very cheap and benign media to do your reaction in!

Be careful to add you bleach slowly and incrementally so as not to overshoot too much as you might precipitate gold hydroxide, although you would need a very large overshoot to do this as the solution is buffered. Just add enough to dissolve all the bits, then stop.

For now this is all theoretical, but I trust you might enjoy the experimentation and see the merits in this approach.

References:

Obtained online from:
(1) http://www.semos.dk/Per/41653/download/Pourbaix_multielement...
(2) http://pubs.rsc.org/en/content/articlelanding/2015/ja/c4ja00... whose image obtained online from Google image search with keywords "chlorine pourbaix".
(3) http://www.sigmaaldrich.com/life-science/core-bioreagents/bi...

[Edited on 14-9-2015 by deltaH]

deltaH - 14-9-2015 at 03:08

Or even simpler, just add enough salt to vinegar to make a 1M sodium chloride solution and that would be good enough, even if it's more acidic. The addition of bleach will result in a buffered system anyway in this case, since bleach is alkaline. With a bit of luck, the resulting solution is not acidic enough to allow the formation of chlorine gas.

Finally, since you probably want to economise on reagents as much as possible, you may want to calculate how much reagents to use and allow for say 50% excess.

So for example, the half reactions for gold dissolving in chloride is:

2Au + 8Cl- => 2AuCl4- + 6e-

and for hypochlorous acid as oxidant:

3HClO + 3H+ +6e- => 3Cl- + 3H2O

So the overall reaction cancelling out is:

2Au + 3HClO + 5Cl- + 3H+ =>2AuCl4- + 3H2O

From an estimated 1g gold, you can back-calculate the amount of sodium hypochlorite solution needed at the concentration you buy it. With some fancy chemistry calculation, you can also calculate the amount of acetic acid you would need that would result in a pH of 5-6 when all is said and done, though this is probably easier to determine experimentally. Don't forget to allow for some excess.

Similarly, you can also consider the pourbaix diagrams of your base metals and construct better and more economical processes for their dissolution. There may even be papers published about this. I've seen such a study taken for the recovery of tin from tin plate waste (cans etc.).

Ideally, you would want to use just air as your oxidant and not peroxide to reduce costs and you already using it to agitate your system!

[Edited on 14-9-2015 by deltaH]

aga - 14-9-2015 at 04:52

That's a pretty full answer deltaH !

Going to give this a try right now.

kadriver - 14-9-2015 at 05:10

This is great info. I can see how a knowledge of chemistry would be so helpful in my experimentation. The explanations given above by aga and deltaH are exactly the kind of information I was after. Even though I didn't quite understand it all, it has made it quite clear that I must begin a study of chemistry to be able to do the kind of research I want to do.

I have dabbled with some of the platinum group metals. I have gotten about four grams of palladium from some previous experiments. But there is much more chemistry involved. Compared to the platinum group metals, gold and silver are "like following a cookie recipe".

Thank you for those replys, very helpful indeed!

kadriver

deltaH - 14-9-2015 at 05:22

Thanks, but take note, I'm under the affluence if vast quantities of codein phosphate, so I might just be missing some crucial aspect.

Some more blah blah:

If you rewrite the overall equation with regards to what we actually are using, i.e. sodium hypochlorite.

2Au + 3NaClO + 5NaCl + 6CH3COOH =>2NaAuCl4(aq) + 3H2O + 6NaCH3COO(aq)

Hopefully that's balanced. Someone, please check.

Now we can work out how much bleach to add and also know how much sodium acetate will form.

From the amount of sodium acetate that forms and this:

Quote:

mixing 70ml 0.2M sodium acetate solution with 30ml 0.2M acetic acid will give a buffer at pH 5

One can work how much extra acetic acid you need and volume of water to end up with the pH 5 buffer ignoring the sodium tetrachloroaurate. Don't forget you also make some water in that reaction and also remember you need six moles of acetic acid per 2 moles of gold to generate that acetate in the first place. I think this calls for the power of grey skull (or EXCEL and solver).

I'm too sick to do this now, but with this roadmap, I'm sure others can succeed.

NB: Pourbaix diagrams show the speciation of ions based on thermodynamics, they say nothing about kinetics (speed of reaction), just that given enough time, when things equilibrate, that's what you end up with. So that said, I would expect this reaction possibly to be slower than what was observed before, but since you can work out exactly the amounts to dose even at once, you just let it stand for a few hours if it's too slow.

aga - 14-9-2015 at 05:53

It's been minutes now, and nothing much happening ...

Edit:

If you're totally new to all the workings-out, here's a couple of brief explanations about Balancing equations and working out Moles and Molarity :-

Attachment: Balancing Equations.pdf (44kB)
This file has been downloaded 676 times

Attachment: Moles and Molarity.pdf (61kB)
This file has been downloaded 669 times

Appologies if they're too simplistic.

[Edited on 14-9-2015 by aga]

IrC - 14-9-2015 at 06:29

Process for recovering metals, in particular precious metals, from electronic scrap

United States Patent Application 20040179985

Attachment: US20040179985A1.pdf (80kB)
This file has been downloaded 774 times

deltaH - 14-9-2015 at 06:49

Okay, dosed up, feeling a little better, can attempt some number, but take it with a big pinch of salt (excuse the pun).

So let's work on a basis of 1g Au

Moles Au = 1g / (197g/mol) = 5.076mmol.
Moles of NaOCl required = 5.076mmol/2*3 = 7.614mmol.

Assuming bleach is 3.5% m/v sodium hypochlorite, that means we need (7.614mmol)/1000*(74.44g/mol)/(0.035g NaOCl/ml bleach) = 16.19ml bleach.

To start with, just for the equation, the amount of acetic acid we need is (5.076mmol)/2*6 = 15.228mmol
Assuming vinegar to be 5% acetic acid m/v, that means we need (15.228mmol)/1000*(60g/mol)/0.05g acetic acid/ml vinegar) = 18.27ml vinegar (not counting the extra we will need to buffer with).

Now to work out the requirements to buffer this sucker.

Previously it was stated that for 70ml of a 0.2M sodium acetate solution...
First lets work out how many moles that is: 70/1000*0.2mol = 0.014mol or 14mmol of sodium acetate.

But how much sodium acetate did we actually make from our 1g gold: 15.228mmol
So using some ratio and proportion, we need: 15.228mmol/14mmol*70ml = 76.14ml to generate the portion of 0.2M sodium acetate solution.

For the recipe for the buffer, the 70ml 0.2M sodium acetate solution was mixed with 30ml 0.2M acetic acid, so using ratio and proportion again:

Amount of 0.2M acetic acid required: 15.228/14*30ml = 32.63ml 0.2M acetic acid.

But how much vinegar would yield that amount of acetic acid? 32.63ml/1000ml*0.2mol/l = 6.526mmol

That's 6.526mmol/1000*(60.5g/mol)/(0.05g acetic acid/ml vinegar) = 7.89ml vinegar

In addition to the amount required for the equation.

So the total amount of vinegar required is 18.27ml + 7.89ml = 26.16ml

Now finally we need to work out how much water to add to dilute this system.

From the buffer recipe, we want a total amount of water of 15.228/14*100ml, assuming the ions don't contribute to volume.

That's 108.77ml water. But the reaction makes some water and the vinegar and bleach 'bring' some water, so we need to subtract those.

Reaction water = 5.076mmol/2*3/1000 * 18.02g/mol= 0.137ml (neglegible)

Water from acetic acid = 26.16ml (assuming the acetic acid doesn't contribute significant volume... it does slightly because it's not fully ionised, but the conc. is very low so probably not much) = 26.16ml

Water from bleach = 16.19ml (again assuming the ions have no volume) = 16.19ml

So water needed to be added = 108.77ml - 0.137ml - 26.16ml - 16.19ml = 66.28ml

Amount of NaCl required for 1M solution is 108.77ml total water (and assumed volume) /1000ml * 1M * (58.44g/mol) = 6.36g

SUMMARY:

To dissolve 1g gold flakes (rounding number up):

Dilute 27ml 5% m/v vinegar with 66ml water to which you add your gold.
Then add 17ml 3.5% m/v bleach.

Stir and wait...

EDIT: and 7g NaCl of course!!! :mad:

[Edited on 14-9-2015 by deltaH]

deltaH - 14-9-2015 at 06:51

Quote: Originally posted by aga

It's been minutes now, and nothing much happening ...

[Edited on 14-9-2015 by aga]

Aga, what gold are you using, the same type of flakes or a piece of gold? This is a surface reaction, so these ultrathin flakes would dissolve far more rapidly than bulk gold. For the flakes, the gold need only 'corrode' by some microns in depth to be gone.

Another possible problem is that maybe the bleach is reacting with the vinegar. If so, we should change to a more inert weak acid.

Finally, maybe the amounts matter, try using the one I worked out earlier, to repeat (note I forgot the NaCl earlier, now corrected):

1g gold flakes
27ml 5% m/v acetic acid (white spirit vinegar)
66ml water
17ml 3.5% m/v sodium hypochlorite (household bleach)
7g NaCl (table salt)

[Edited on 14-9-2015 by deltaH]

MrHomeScientist - 14-9-2015 at 09:30

Quote: Originally posted by kadriver

... using only household chemicals through the whole process.

Using only household chemicals, and your household fume hood and household acetylene torch

Not quite so easy!

A fume hood is definitely required for this. You've got tons of HCl, chlorine, and sulfur dioxide fumes throughout the process. I wouldn't be comfortable doing this outside, even. It'd be impossible to work next to! Very cool video though, I enjoyed watching it. If I ever get around to making my fume hood, this is something I'd like to try out.

deltaH - 14-9-2015 at 10:32

I also wanted to have a closer look at the prior step, the one where the base metals are selectively leached.

Let's start with copper's pourbaix diagram in chloride media of course from a thread on SM no less (1)

(1) http://www.sciencemadness.org/talk/viewthread.php?tid=7156

Notice that under acidic conditions copper is most oxidised to copper (II) chloride, but can also form copper (I) when less oxidised.

Copper (I) in concentrated chloride solutions can also form dichlorocuprate(I) anions, CuCl2-, making the copper (I) chloride soluble.

Possibly the copper is acting as the oxidant here and being reduced to copper (I) species, which is then regenerated/oxidised back to copper (II) by reaction with dissolved oxygen from the bubbling.

Perhaps the peroxide just kick starts things by leaching some initial copper.

Also notice from the diagram that a mixed media of copper (I) and (II) isn't very strongly oxidising, this is maybe the secret to this step's selectivity, i.e. in not leaching gold. From my first gold pourbaix diagram, the solution needs a minimum potential of 0.8V to be able to even start to oxidise any gold.

Instead of concentrated hydrochloric acid, here too it might be possible to make a substitution using 'salted vinegar'. Again, it might be kick started with addition of hydrogen peroxide, but it's the air from the bubbler that regenerates the oxidant and keeps things leaching over until it's all done.

If air is the key here, one way to improve this is then to improve the mass transfer of air, i.e. have a bubbler that has a diffuser on it to make very small bubbles so there is a larger surface area for oxygen to diffuse into the water, which is usually the rate-limiting step in such systems. Pressure is another method of speeding up this mass transfer, but that is extremely dangerous if you don't know what you're doing, so I'm hestitant to say more about that...

You can always use a combination of bubbling air with large bubbles to keep things thumping about together with a second bubbler with a fine frit to make diffused bubbles that up's the rate, but doesn't help much with agitation.

[Edited on 14-9-2015 by deltaH]

kadriver - 14-9-2015 at 21:30

Quote: Originally posted by MrHomeScientist

Quote: Originally posted by kadriver

... using only household chemicals through the whole process.

Using only household chemicals, and your household fume hood and household acetylene torch

I have done this one time in the past when I did not have a fume hood. I did it in my back yard away from people or animals.

If you cover the beaker the sulfur dioxide was not a problem (that I can remember).

I could have used a MAP gas torch (available at the hardware store) to do the melt. It would have taken much longer - 10 to 12 minutes to melt the gold.

The oxy/acetylene did it in just 4 or 5 minutes. Oxy/acetylene torch set available for about $300 at Harbor Freight.

The chlorine is a different story. I used HCl and bleach to leach some precious metals outside in a bucket before I had my fume hood. I could not smell the chlorine so I got close and then got a wiff of it - it nearly brought me to my knees. I had to sit down and gather my composure for a few minutes afterwards.

You are absolutely right - those gasses are nothing to fool with, very dangerous.

kadriver

deltaH Golden Fish & Chip Recipe

aga - 15-9-2015 at 11:21

Seeing as deltaH had a pretty good idea of what do, i agreed to try it out.

In a 250ml beaker, the following were added :-

~6 gold plated fingers cut from RAM boards
1 ancient AMD CPU chip with loads of gold plated pins
200ml 8% white vinegar
10ml 3% H₂O₂
11.7g table salt NaCl (~1 Molar concentration)

This solution was left to react overnight with air being bubbled through it using an aquariaum pump.

No Airstone was available, so the plastic delivery tube was plugged, and several small holes made in it to spread the bubbles out.

Here are the starting materials and the 'rig' :-

The next day it was found that the solution was not really working very well, and had gone a green colour :-

An executive decision was taken by High Command to increase the NaCl concentration to 2 [M] so another 11.7g of NaCl was added.

There was no sense in having the CPU chip in the mix, as this step was simply to separate the gold foils from the copper, so the CPU was removed.

This appears to have been more effective :-

One strip of fingers appears to be mostly intact, indicating that it was produced by some other process, probably with a different Cu thickness, a different solder resist mask or something.like that.

All of the above has been conducted at ambient temperatures, currently ranging from a bone-chilling 18 C at night up to around a survivable 28 C during the day

The last photo doesn't show the colour well, yet there is a fine green-blue-white crust around the rim of the beaker.

Next step will be to filter out the gold leaves and see if we can dissolve them.

Edit:

At all times it honks of Vinegar without even a hint of chlorine.

[Edited on 15-9-2015 by aga]

[Edited on 16-9-2015 by aga]

kadriver - 15-9-2015 at 17:07

Vinegar, salt and hydrogen peroxide did that? Nice work you guys! I wonder what would happen if the finger that stayed together was allowed to stay in the bubbled solution for another day? Cool experiment.

kadriver

kadriver - 15-9-2015 at 17:15

Aga, would you mind if I scale up and repeat your experiment using your numbers and make a video of it posted to my YouTube channel?

kadriver

aga - 15-9-2015 at 23:09

It's deltaH who came up with the idea, not me.

Sure you can make & post a video.

It'd be interesting to see what happens at a larger scale.

A few smaller scale experiments with say 2, 3, 4 [M] NaCl might be a good idea to get a feel for the most effective quantities to use.

Edit:

Maybe call the video 'Step #1' as there is a good chance that deltaH's recipe for dissolving the Gold will work out fine as well.

Further Edit:

Just checked the pot and the foils have started coming off the stubborn strip as well.

[Edited on 16-9-2015 by aga]

deltaH - 16-9-2015 at 00:00

I'm also very happy with this. The whole idea is to have people using safer and environmentally more benign reagents when doing this kind of work. Both he and I would love to see this scaled up!

We would greatly appreciate it if you could link to this thread there so that SM can be promoted. We might also help people with further questions. No doubt this route will evolve a little more in time.

Aga will be 'out-of-office' for a few days, but the plan was to filter the slurry through a porous filter so as to capture the gold, but let through the finer milky precipitate (presumable suspensions of copper(I) chloride?). It might be possible to subsequently filter this copper(I) chloride by using a fine filter paper and then recycle the filtrate liquid as is for the next batch. If so, there's an 'out' for the copper, which is nice.

In a second step, an attempt to dissolve the gold in a mixture of salt, vinegar and bleach was to be made which you should feel free to do as well.

The recipe numbers are stated above. Be aware that because the solution doesn't start out buffered, some small amount of chlorine might initially be evolved as a result (or not... we just don't know yet). But even so, it's so much simpler to use vinegar straight without first preparing sodium acetate, etc. Sodium acetate and the buffer will form anyhow as the oxidation proceeds, so the good news is that the final solution should be buffered and relatively benign.

Please DO post links here to your videos, we'd love to see more of them!

[Edited on 16-9-2015 by deltaH]

kadriver - 16-9-2015 at 05:58

So to get started I'm going to scale up by a factor of 10, except for the fingers, I'll use 500 grams of those.

I'll use 2 liters of white distilled vinegar (200 x 10 = 2000ml) from the grocery store.

100ml hydrogen peroxide 3% (10ml x 10 = 100ml) off the shelf at the drug store.

And (11.7 + 11.7 = 23.4g) x 10 = 234g sodium chloride - table salt.

And 500 grams of trimmed circuit card fingers.

All in a 4 liter beaker.

I'll add an air bubbler to provide agitation and O2. Is this O2 required as part of the reaction to lift the gold foils?

Since I'm not a chemist, could you please provide a brief description of the reaction in plain English (for me to include in a text panel in the video) without acronyms or terms that are too technical?

Thanks for your help! I'm looking forward to this.

kadriver

deltaH - 16-9-2015 at 06:50

Sounds good kadriver. It should take 48h for complete removal, although after 24h many should have separated already.

We don't yet know what the mechanism is for sure. Specific experiments would need to be designed to prove the hypothesis.

That said, my hypothesis is that the peroxide kick-starts things and get's some initial metal salts into solution relatively quickly, but that air is the net oxidant over most of the run.

In subsequent runs, if you recycle the solution used, you probably don't need the peroxide since the salts that are doing the work are present.

What we're really dying to know is whether the bleached salted vinegar dissolves gold in the next step. It sounds insane, but the Pourbaix diagrams suggest it should, even if it is a lot slower. I'm holding my breath

[Edited on 16-9-2015 by deltaH]

macckone - 16-9-2015 at 08:23

A note on recycling electronics.
Silver and copper are where the money is.
Circuit boards actually contain more of these two
than the average ore extracted from the ground.
But the recycling is only cost effective in bulk.
And you need to recycle your solvents etc to
make it worth while.

They use wood chippers and shred everything
Then process it like ore. They get out a sludge
that is high in rare earths as well. That is further
processed at a different plant where it is mixed
with actual ore.

kadriver - 17-9-2015 at 00:13

I bought the vinegar and salt (I chose non-iodized sea salt).

I've got everything else.

However I was already into a new video and I am trying to get it published right now - building and operating a sulfuric acid stripping cell to de-plate the gold off of gold plated items, jewelry.

I'll be able to start this vinegar and salt experiment Thursday or Friday.

I'm kind of sceptacle of the vinegar and bleach dissolving gold - but what a neat discovery that will be if it works!

deltaH - 17-9-2015 at 01:09

kadriver, I suggest you double the quantities for the bleach reaction just to make sure you have excess reagents to do the dissolving, but you should add them in two portions, but NB I wouldn't prepare the second portion straight away, because once the bleach is acidified, it is unstable and will break down into chlorine, so you want it seeing gold at that point, else it will lose its oxidising power .

Add the first, wait for some decently long length of time, then the second. Exactly how long, I cannot say, we shall have to wait and see. Experience will tell how much excess reagent is required to do the job, but the idea is not to go extreme, that would be wasteful.

My knee-jerk reaction about this dissolving gold is the same, but I'm also trying to have some faith in the theory even when what it is suggesting sounds so unbelievable.

It's important to understand that it isn't the vinegar dissolving the gold, it's acidified bleach and this is the same as before. This takes gold to 3+ ions which then is quickly complexed by chloride ions, something which gold 3+ has a very strong affinity for. It doesn't matter where the chloride ions come from, so long as they are present in reasonable proportions, hence why one can simply use table salt. The gold 3+ ions once formed will quickly bind chloride while the vinegar mops up the rising alkalinity generated by the oxidation to keep things acidic.

aga - 17-9-2015 at 04:18

I'll be back tomorrow (in Sevilla at the mo) so will get the Bleach & Gold thing started.

Cool ! The race is on !

Little_Ghost_again - 17-9-2015 at 04:24

This is so cool! I am hunting for gold to try lol, man if this works you would have solved a big problem waste and cost wise. If I can get the Hydrogen peroxide (and gold) I will try, I only have 10% acetic acid. I could get normal vinegar but no idea how strong it is, I spose I could boil some down

[Edited on 17-9-2015 by Little_Ghost_again]

deltaH - 17-9-2015 at 04:47

I based my calculations on 5% acetic acid... so you don't need it strong!

Also, we don't even know if the hydrogen peroxide is completely necessary, it might work even without, just take longer to get going, so maybe you can test that particular hypothesis for us!

Also, once you have a batch made, you can use the spent solution for the next batch because it already has a whole lot of the metal salts dissolved, so no kick-starting required... maybe.

aga, oh that's right, your back tomorrow... go aga go aga go, go go, ah...

It would also be good to try it small scale first and work out the bugs so that kadriver can scale up. Not that it would matter much, because if it fails and doesn't dissolve, he could still dissolve it by other means after a little rinse.

[Edited on 17-9-2015 by deltaH]

Little_Ghost_again - 17-9-2015 at 10:07

I have some old chips with gold bonding wires in and will look for ram chips in a couple of old pc's, ok I will try without the peroxide

deltaH - 17-9-2015 at 10:41

Thanks, that'd be great. Remember to use 2M NaCl, the 1M didn't work so well for the copper leach step.

Little_Ghost_again - 17-9-2015 at 17:11

Ok as I dont have much containing gold to chuck at this, I thought I would do a couple of tests first with just copper. I figured if the first step was leaching copper then I could use some thin pcb board with a thing copper coating (the board is new and unused).
I can see what effect it is having on the copper first without gold getting in the way, Its a very thin coating so will cut into strips like the fingers. The other thing I would like to try with everyone's approval, is using a small electric current. From what I can gather as long as I say keep to around 0.6V I should be ok?
I have a ATX supply with 3.3V output and a linear technology low drop out regulator, I could use that with a diode in series or even just a few diodes in series on the 3.3V line. The Voltage wont be a problem as long as I measure the actual drop and watch the temperature, I will run it along side the gold fingers (when I am happy I have things right) as well. So I could test both with and without electric and see if that does anything?? I intend to keep the current low ~250mA?
When the time comes to use the gold fingers I could sandwich a finger board between a pcb or even a MMO mesh? that way all the fingers have the Volts going through them.
Anyone think using electricity is a bad idea? (from a safety point?)

deltaH - 17-9-2015 at 22:00

Nice ideas, but I don't think applying a voltage to the PCB fingers directly will be practical. While you might get it right by carefully 'sandwitching', these guys want to process 100's g (maybe even kg's) of randomly cut fingers and I strongly doubt you will get them all to make electrical contact without a lot of effort.

However, you might be able to use electrochemistry in a more generic way, on the solution itself. For example, if an anode could take Cu(I) to copper Cu(II), then it might be able to replace the role of oxygen. It's probably Cu(II) that's doing the actual leaching of the Cu(0) and then forming Cu(I). Then on the cathode, you could reduce copper ions in turn to copper metal than can be recovered.

If you can make an MMO basket (like a chips fryer) to hold all your cuttings, this should work, though it's not required to be a basket per say.

This is become a real fish and chips operation!

[Edited on 18-9-2015 by deltaH]

Little_Ghost_again - 18-9-2015 at 01:17

Nice ideas, but I don't think applying a voltage to the PCB fingers directly will be practical. While you might get it right by carefully 'sandwitching', these guys want to process 100's g (maybe even kg's) of randomly cut fingers and I strongly doubt you will get them all to make electrical contact without a lot of effort.

However, you might be able to use electrochemistry in a more generic way, on the solution itself. For example, if an anode could take Cu(I) to copper Cu(II), then it might be able to replace the role of oxygen. It's probably Cu(II) that's doing the actual leaching of the Cu(0) and then forming Cu(I). Then on the cathode, you could reduce copper ions in turn to copper metal than can be recovered.

If you can make an MMO basket (like a chips fryer) to hold all your cuttings, this should work, though it's not required to be a basket per say.

This is become a real fish and chips operation!

[Edited on 18-9-2015 by deltaH]

Hi.
Yeah guess I didnt think it through

, I will try a basket or something similar along side the 'normal' Way

.

This is what I like best about this place! If something catches peoples minds things get done, its alot like the sodium thread. An idea is first scoffed at then everyone gets together and starts to experiment

........One day Gold from lead might come out of here, I hear they been working on that one for a VERY long time lol

[Edited on 18-9-2015 by Little_Ghost_again]

[Edited on 18-9-2015 by Little_Ghost_again]

aga - 18-9-2015 at 06:45

Aaaaand it's Gone ! https://www.youtube.com/watch?v=-DT7bX-B1Mg

The Gold foils were vac filtered from the vinegar/salt/H₂O₂ solution, and then washed from the filter paper into a clean 250ml beaker as there was other brown gunk on there.

This lost some particles of gold, however it made the results clearler to see. Gentle swirling of the beaker brought most of the gold into a pile in the middle.

The fingers still had some gold attached although the 'stubborn' one lost all the gold from one side and ~60% from the other. Stirring would have helped.

The water was brought to approx 66mls and 7g of NaCl table salt was added, and stirred to dissolve.

Then 17ml of some bleach claiming 36g/100ml hypochlorite was added. The liquid measured pH 4.1 on a digital meter at this point.

Immedately a strong chlorine smell was noticed and should have been out in the fume hood. It would have been more useful to add the hypochlorite ml by ml while stirring.

Within 5 minutes of stirring ALL of the gold foils had dissolved !

Woohoo !

Huge congratulations to deltaH for inventing a NEW gold recovery process ! Well done indeed !

[Edited on 18-9-2015 by aga]

aga - 18-9-2015 at 06:49

Next up is that CPU Chip.

It has been hot-glued to a plastic stir rod and is being twizzled in the solution.

30 minutes in and the pins are showing signs of corrosion, with bare copper clearly seen.

Edit:

Assuming this has all worked out well, how do i get the Gold out ?

Just filter then sprinkle in sodium metabisulphite ?

[Edited on 18-9-2015 by aga]

It's been about an hour now, and not much happening, so another 2g NaCl, ~2ml vinegar and 1ml hypo added.

Seems to have speeded up the leg corrosion.

The stick fell off, so the chip has been wedged in the pot with a bubbler tube.

The liquid is now significantly Brown in colour, reminiscent of a sodium acetate solution.

[Edited on 18-9-2015 by aga]

deltaH - 18-9-2015 at 08:23

Wow, amazing work aga! My 'inventing' is pretty useless paper chemistry without friends like you actually getting it done. Thanks again.

I think for the future then, to minimise the copious amounts of chlorine made, one should definitely prepare the sodium acetate/acetic acid buffer as stated with the earlier recipe above somewhere, before adding the bleach.

I think it was 70ml 0.2M sodium acetate + 30ml 0.2M acetic acid?

[Edited on 18-9-2015 by deltaH]

MrHomeScientist - 18-9-2015 at 09:25

This is some extremely interesting work! Great example of collaboration between the theorists and the experimentalists.

Aga, I would think metabisulfite would work as in the 'usual' recovery process. Or you could cement it out with a more reactive metal (read: any metal lol).

Did the solution also dissolve the bare copper on your CPU chip, or just the gold? I wonder how selective this process is.

Edit: I wonder where AJ is... bleach and vinegar actually did something. He should be all over this one!

[Edited on 9-18-2015 by MrHomeScientist]

Little_Ghost_again - 18-9-2015 at 09:43

Wooo thats amazing!! Mine is about to be set up

, I have some old circuits boards (very old modem boards) I will use those and see how selective it is, I might also add some blobs of new solder without the lead in and see how that does.

[Edited on 18-9-2015 by Little_Ghost_again]

aga - 18-9-2015 at 10:02

The CPU chip resisted more. Firstly there was some copper colour appearing, then the legs went black where the Gold had dissolved :-

A quick attempt was made to precipitate some gold using (left to right)
NaOH
3% H₂O₂
Fresh Filtered Lemon Juice (smells wonderful)
Sodium Metabisulphite (loads and loads of it)

Not much joy really, but then, the quantity of Gold here is infinitessimally small.

Only the NaOH-treated solution has some suspended solids.

Will wait a while to see if they settle.

deltaH - 18-9-2015 at 10:05

Colloidal gold!!! Gold nanoparticles!!!

https://en.wikipedia.org/wiki/Colloidal_gold

The last one is typical.

[Edited on 18-9-2015 by deltaH]

Little_Ghost_again - 18-9-2015 at 10:25

TUT TUT I can see gold left on that chip

, maximise your profit aga

, so how do we go about getting the copper back?

deltaH - 18-9-2015 at 10:49

TUT TUT I can see gold left on that chip

, maximise your profit aga

, so how do we go about getting the copper back?

Iron should do the job as kadriver showed on his tailings pot video.

[Edited on 18-9-2015 by deltaH]

aga - 18-9-2015 at 11:18

TUT TUT I can see gold left on that chip

Sorry.Very lax indeed.

I was a bit excited, seeing as it was a World First in the Entire Human History of Gold Refinery.

The notion of getting it 100% right before posting the preliminary results slipped my mind (such as it is).

Little_Ghost_again - 18-9-2015 at 11:58

Quote: Originally posted by aga

TUT TUT I can see gold left on that chip

Ok I will let you off this time! Yes it is very exciting, it would sure be a biggy if it changed how it was done on an industrial level.

I am playing with temperature as well at the moment and NO hydrogen peroxide. I will post an update as soon as anything happens

aga - 18-9-2015 at 12:10

I am playing with temperature as well at the moment and NO hydrogen peroxide. I will post an update as soon as anything happens

Cool !

Photos please of the Nitrogen Oxide Hydrogen Peroxide compound.

Even a ball-and-stick model would be fantastic

Little_Ghost_again - 18-9-2015 at 12:31

There you go

I think the ball and stick model is something like this

aga - 18-9-2015 at 12:39

LOL !

One day LG2.759 you shall do some actual chemistry.

Until then, carry on regardless !

[Edited on 18-9-2015 by aga]

Actually, you made a good point.

I will go and chuck various stuff into a deltaH solution and see what happens.

Lead, Tin, Copper and stuff.

[Edited on 18-9-2015 by aga]

Little_Ghost_again - 18-9-2015 at 12:56

Have a look at this
www.mdpi.com/1996-1944/7/6/4555/pd

There is a right mix in some boards, the main problem (UK perspective) is we class older boards as toxic waste because they contain heavy metals and lead. now if we can find a way to recover those then what we are left with is the fiber glass bit, looking around it seems on the bigger scale boards are powdered up then refined to recover the metals.
This has me thinking about the left over fiber board powder, I am wondering if it would make a good additive in cement. Maybe if enough could be added it would make normal cement more insulating?
Dont get me wrong the gold recovery is a big thing, but you have a clean way to get the copper and gold so why not see if you can get the others? As mad as it sounds this could all end up really useful, especially if we can find a way to speed it up a little.
I do some chemistry but mostly things go wrong so I keep quiet about it

.
So how do we go about tidying up these results? I will see if I can find out whats in the AMD processor metal wise, any idea what chip it was?

aga - 18-9-2015 at 13:09

Fibreglass regularly finds it's way into Concrete as an alternative to Steel.

Costs more than the Concrete weight for weight.

Failed experiments tell us a lot more than those that succeed ...

Little_Ghost_again - 18-9-2015 at 13:14

if it costs more than weight for weight then that makes it worth recovering if your doing it on a large scale?
I know we are looking at gold recovery but I stumble on a page that gives some examples of rare older processors that are worth a fortune intact. It also mentions that the pentium pro processor contains the most gold (processor wise) with around 1g per processor.
I got kinda bogged down at hat point after finding this
http://micro.magnet.fsu.edu/creatures/index.html

It appears that some manufactures had designers that hid little pictures made of gold inside chips, that page is a gallery of some

aga - 18-9-2015 at 13:20

Well, you can spend your life looking for Gold if you like.

Not a lot of point in the end.

Better spend your limited time enjoying yourself rather than searching for Riches unattainable.

Little_Ghost_again - 18-9-2015 at 13:30

Pk a more serious topic.
Time for a word of caution, I have been breaking up some old boards with a hammer. These are a mix of very old and some newer boards I have kept for spare parts off them. In gold fever I was happily bashing away to crack open the goodies etc and pounded on a metal box on the board, BIG mistake. What I smashes open turned out to be a mercury wetted relay! So now I have mercury splashed all about the place and on my jeans

, this got me thinking about possible reactions with stuff like mercury and Tantalum bead caps etc.
Might be an idea to have a think of some of the other things on boards we might come up against, Tantalum is pretty common on boards so any idea if it will react with this method? and if so is it anything to worry about? Now I got to go and try and find small bits of mercury!! Its more a warning to lurkers who might be trying to give this a go, there seemed to be a fair bit of mercury inside the relay. I have some more of these relays on another board, I will desolder them before I smash the board

aga - 18-9-2015 at 13:40

Wow!

How Lucky art thou ?!?!

To get hit with a mere splash of the tiny amount of mercury in a wetted relay and then to notice the fraction of 0.01g of anything hitting your jeans !

The Lord is Surely With Thou, O LG2.801

Better bullshit please. Drink less and remember where you are.

Little_Ghost_again - 18-9-2015 at 13:43

Hmm Time for pic and a datasheet

BRB

Little_Ghost_again - 18-9-2015 at 14:06

Couldnt find a sheet but here is a pic

I had scales on wrong read out but its 27 grams, if you shake it then you can hear it move about inside, I would roughly guess twice a normal lab thermometer worth inside.
If you can hold off until tomorrow so I can get some sulphur I will Dremel the sucker open and weigh the mercury. But its sure as hell alot more than your thinking!
Oh and I dont drink

I seen what it does to others

[Edited on 18-9-2015 by Little_Ghost_again]

aga - 19-9-2015 at 02:04

I stand corrected.

If you can hear it sloshing about, then there's certainly enough mercury in there worth recovering, and you should spin that process off in another thread.

aga - 19-9-2015 at 02:06

Having left the test tube samples overnight, the one with NaOH has developed a dark black-green lower layer and the one with sodium metabisulphite has a spongy reddish precipitate lying on top of undissolved bisulphite.

Little_Ghost_again - 19-9-2015 at 02:12

Thats really interesting, I know this sounds stupid but. I know that there is a gold test where if the gold isnt great it turns like the colour of the NAOH one.
Is it possible/likely the NAOH one picked up some copper from the AMD chip? Not sure what I am thinking at the moment

[Edited on 19-9-2015 by Little_Ghost_again]

deltaH - 20-9-2015 at 06:12

As I suspected, there is very little that is 'new' these days. I had a look in on a site goldrefiningforum.com. It requires one to register to search, but low and behold, there is a thread from 2013 on "pin foils with vinegar, peroxide, and salt"

Seems they suspect the same as what we discussed, Cu(II) is doing the etching and reducing to Cu(I) which is then re-oxidised by an oxidant (air or peroxide).

Similarly, from 2014, "bleach, vinegar and salt dissolve gold"

It easy to reinvent the wheel these days :mad:

With such knowledge out there, I wonder why its use hasn't been more common place?

*****
A word on recovery of the gold from solution post dissolution. In industry, activated carbon is used to adsorb gold from cyanide solutions. Called the 'carbon in pulp process' if I'm not mistaken.

I wonder if that might not be applied instead of reducing agents. Granulated activated carbon is very cheap and will mop up even dilute solutions nicely.

Activated carbon manufacturers have special grades of carbons specifically optimised for removing gold from solution, so if one is inclined to do this on a larger scale, it's maybe worthwhile to procure a bag of this from them.

[Edited on 20-9-2015 by deltaH]

Little_Ghost_again - 20-9-2015 at 08:29

As I suspected, there is very little that is 'new' these days. I had a look in on a site goldrefiningforum.com. It requires one to register to search, but low and behold, there is a thread from 2013 on "pin foils with vinegar, peroxide, and salt"

My guess would be time is the factor that limits the uptake of this method, few in the industry seem bothered about waste and want to reclaim as fast as possible, but I doubt they have worked out the cost factor of materials in this.
Personally I think this line is well worth pursuing, especially with the other thread on lead and tin etc.
LG

kadriver - 22-9-2015 at 19:23

I am a member of the GRF and I have never seen the post for vinegar salt and peroxide.

Neat to know that the bleach will dissolve the foils.

Aga, keep in mind that I had 500 grams of fingers, and only got 1 gram of gold.

Also, see my new video on stripping gold off gold plated items with an electrolytic cell. In part 2, when I added the SMB, nothing happened (because there was such a small quantity if gold in solution).

With such a small quantity of gold in solution - less than 1 gram per liter - the gold precipitates and settles very slowly.

It did ppt and settle after sitting over night - see the video, end of part 2.

Anyway, I started the scale up experiment this evening.

kadriver - 22-9-2015 at 19:30

Here is the fingers being aerated in a solution of 2 liters of white vinegar, 235 grams of sea salt, and 100ml hydrogen peroxide. I started the experiment at 10:30pm on Tues 22 Sep 2015.

Here is a picture of the experiment immediately after starting.

kadriver - 22-9-2015 at 19:37

Then went to take a shower and when I came back 1/2 hour later the solution had already begun to turn blue from the copper dissolving.

I am also doing a video documentary of the entire process. It should be ready to publish in a few days.

What a great thing to be able to do, even though it's already been done on the GRF.

I just wish that these videos were around back when I was learning how to do all this.

kadriver

deltaH - 22-9-2015 at 22:24

Very nice work kadriver! I'm so excited to see this after 48h (though a good deal should be off in 24h). Thank you for scaling up!

Yes from the little I could see, the GRF looks like a very large forum, especially considering it's all about one topic. I think info just slips through sometimes. I did notice that those threads lacked some important details. I don't think it was well understood at that point and possible people couldn't reproduce it with the given details and so it lost momentum? Not sure why it went dead so quickly and more investigations not performed. The info on the oxidant was particularly hazy, I think the key here is that bubbling is very important. While the peroxide might work initially, it breaks down quite quickly to water and oxygen in the presence of transition metals which act as catalysts, so it's activity would quickly diminish.

Furthermore, these kinds of important discoveries ought to be highlighted so as to disseminate the information. This additional thread and also your youtube videos should go a long way to publicizing this better.

[Edited on 23-9-2015 by deltaH]

aga - 23-9-2015 at 08:52

Fact that it's been done before, but nobody knew about it tells us something important : publicise your work or it gets forgotten !

Sad to think that vast quantities of PCBs have been dunked in concentrated nitric acid when they could have been doing this instead.

Can't wait to see the video !

deltaH - 28-9-2015 at 02:00

I wonder what happened to kadriver's experiment. It's been many moons now

kadriver - 4-10-2015 at 21:13

Hello,

Sorry it took so long. The experiment was progressing nicely, then I got swamped with work.

I left the bubbler in for about 6 days. On day five I noticed a light blue precipitate starting to form in the beaker.

About 98 percent of the foils came off the fingers. I had set the experiment aside to get some important work done.

Then disaster - I dropped a heavy glass lid from another process onto the experiment and broke the 5 liter beaker. It's just set there like that for about a week.

That's usually what happens when I reach a point where I don't know what to do.

Here is a picture.

kadriver

kadriver - 4-10-2015 at 21:20

Things have calmed down.

There is about 50$ worth of gold foils that I need to get out but I'm not sure how to proceed.

Tomorrow I'll decant the liquid, pick out the shards of glass (the glass saucer I had sitting on top also broke and fell down into the experiment) then transfer to a new container so I can carry on the experiment.

I have no idea what the blue precipitate is. I'll get some samples and start running some tests to see if I can find a solvent that will dissolve the light blue ppt but leave the gold foils.

I have never encountered this type of material, any thoughts on what it might be and how I can dissolve it?

Thanks, kadriver

deltaH - 4-10-2015 at 21:37

Sorry to hear about your disaster.

Sounds like the precipitate may contain copper salts. You ought to be able to wash these through a strainer/sieve and retain your gold fingers. After that I suggest filtering the solutions so you can keep the filtrate for the next batch and recover the precipitate.

The precipitate should dissolve in conc. HCl if it doesn't dissolve well in water alone. You might want to try dissolving a small amount in saturated sodium chloride as well to see if that works, it's more benign than conc. HCl and cheaper! If it contains copper(I) in the mix, then that won't be very soluble in water alone.

[Edited on 5-10-2015 by deltaH]

violet sin - 4-10-2015 at 21:41

might ammonia re-dissolve the copper compound to filter out gold fingers? that is if it is a copper salt we are seeing as the blue ppt.

deltaH - 4-10-2015 at 22:04

might ammonia re-dissolve the copper compound to filter out gold fingers? that is if it is a copper salt we are seeing as the blue ppt.

Oooh, that's going to get really pretty, pretty fast

Nice idea!

[Edited on 5-10-2015 by deltaH]

Little_Ghost_again - 4-10-2015 at 23:10

blimey that must be strong stuff! looks a bit like this

Mine is copper disolved in nitric and sulphuric acid (both conc), so I would say thats copper for sure. Then again I am often wrong

mine been there so long the dark blue on the bottom is crystals! what struck me is how similar the white powder was and how it sticks to the sides of the glass

[Edited on 5-10-2015 by Little_Ghost_again]

How much did it evaporate? I only ask because you said about the plate on top, I am wondering if your white powder is salt? but the blue looks like a fair bit of copper

[Edited on 5-10-2015 by Little_Ghost_again]

kadriver - 5-10-2015 at 04:34

Sorry to hear about your disaster.

Sounds like the precipitate may contain copper salts. You ought to be able to wash these through a strainer/sieve and retain your gold fingers. After that I suggest filtering the solutions so you can keep the filtrate for the next batch and recover the precipitate.

The precipitate should dissolve in conc. HCl if it doesn't dissolve well in water alone. You might want to try dissolving a small amount in saturated sodium chloride as well to see if that works, it's more benign than conc. HCl and cheaper! If it contains copper(I) in the mix, then that won't be very soluble in water alone.

[Edited on 5-10-2015 by deltaH]

I noticed the precipitate in very small volumes starting on day two with the bubbler. On day five it exploded exponentially and started to coat the inside of the beaker.

I have some extra fine copper mesh that might work as a strainer. Also a steal tea strainer that has a fine mesh. Straining out the foils and rinsing the ppt through never occurred to me - thanks for that tip.

As for ammonia, I try to keep it out of my processes. It will dissolve silver chloride and that can be useful. But adding it to waste treatment creates a plume of ammonia that is ruinous to equipment and lungs.

I'll get a sample of the blue precipitate and try a few drops of ammonia to see if it will dissolve the copper salt.

I started filming for this video at the beginning. But I usually try to produce the video as the process is going in real time to keep everything fresh. I can do this because I am very familiar with the process and I know what's going to happen next.

But with this I am in unfamiliar territory. I stopped shooting video when the precipitate showed up. Couple that with the broken beaker and it's not looking good for completing this experiment - on video.

I'll probably get the foils from this batch and start the experiment over, being more familiar with what to expect. THEN do a video showing the complete process.

I'll keep this thread posted on how I proceed from here with photos, but probably not a video this time around.

kadriver

kadriver - 5-10-2015 at 04:41

blimey that must be strong stuff! looks a bit like this

Mine is copper disolved in nitric and sulphuric acid (both conc), so I would say thats copper for sure. Then again I am often wrong

I always try to keep a cover of some sort on the beaker. I did not note the amount of evaporation.

I must say that the concept of using vinegar, salt and peroxide is fantastic, the formation of the blue ppt really throws a wrench into the gears of this process. I didn't expect it.

kadriver

deltaH - 5-10-2015 at 05:53

Okay, some detective work is in order then.

I must say, I'm doubting that this precipitate is copper(I) now considering that it took so long to form and then formed exponentially. That doesn't fit. If anything, prolonged bubbling should oxidise all the copper (I) to copper (II), which I think it did and that is the blue solution you see, especially after [presumably] all the copper has been leached.

The precipitate is something else, could it be tin oxide and/or lead salts from solder?

[Edited on 5-10-2015 by deltaH]

Little_Ghost_again - 5-10-2015 at 07:02

I asked about evaporation because I wondered if the white stuff was salt or maybe lead something. Then again he used fingers I think, so should be no lead as it should be the copper the glue the gold and the stuff they put on top like a varnish (the name escapes me).
How do I make the acetate? mine hasnt turned up.
I am eager to give this another try

deltaH - 5-10-2015 at 08:54

What do your mean by "how do I make the acetate"?

aga - 5-10-2015 at 09:08

The fact that PCBs have a lot of copper on them surely suggests the blue is a copper salt ?

Also it's Blue ...

Little_Ghost_again - 5-10-2015 at 13:10

What do your mean by "how do I make the acetate"?

Sorry was a mix up ignore that.

Little_Ghost_again - 5-10-2015 at 13:16

Quote: Originally posted by aga

The fact that PCBs have a lot of copper on them surely suggests the blue is a copper salt ?

Also it's Blue ...

I think the detective stuff is more to do with the white powder, there is alot of it. Could be copper(I) but I am guessing that would be unlikely. The blue as you say has to be copper, and a fair bit going by the colour, if he added alot of conc H2O2 then maybe the white stuff is copper(I)??
I am pretty sure it wont be lead etc as these were fingers, so unless a fair number had some soldering done to them I cant see lead being in there, that leaves the glues and coatings, depending on the number of layers of the boards used that could be a fair bit. I havnt got a clue what they use as a bonding material.
The only other way out idea is maybe the glass fiber resin came out and created the white precipitate. But judging it against mine (whatever that is) it seems to be the same white powder, I am pretty sure mine is copper of some sort as it only had copper and acids added

kadriver - 5-10-2015 at 21:47