# Urgent Sulfuric Acid Neutralization after IC chip gold recovery



## Dusty3kids (Jul 19, 2021)

I understand my stupidity should not warrant an emergency on your part...but.

Ok, I may be a bit long winded but I want to cover everything...First and foremost I want to say that I admit I am an idiot when it comes to this stuff apparently. I have been researching for couple of months as I can (I am a single father of 15 yr old twin boys and a 17 year old daughter and run my own computer repair business. For as long as I have been researching I have also been depopulating a storage shed full of old PCB's...I got tired of just depopulating and wanted to try to do something...so off to Youtube I go...watched some guy using sulfuric acid and hydrogen peroxide to treat the IC's and BGA's after pulling off the fiber board. So I mimicked. 4 times as much sulfuric acid (98%) as IC's and the same amount of hydrogen peroxide as IC's so 4 to 1 sulfuric acid to hydrogen peroxide. I admit now that I should have read a bit more on how to neutralize and dispose of this solution then I had as I just thought Baking soda would do it...I have made flash cotton and flash paper before but only used 50ml not 1L (oh and I did not have a bottle big enough to fit 4 times the amount of acid, I still used 4 to 1 ratio but could only manage to fit half of the required acid and only realized this after putting the sulfuric acid in the bottle, figured I was already this far let's just make it work) and was able to neutralize it easily. After heating my solution with IC's for several hours I let sit for a few then decanted what I could. Believing that gold does not dissolve in Sulfuric acid I decided it was time to neutralize what I decanted.

Quick pause...I realize I am probably going to be hit from every side here. I also realize at this point I am doing NOTHING more then reading this forum until I have a much deeper understanding of what I am doing...I will say that I have mask rated P100, apron, face shield, and gloves that almost reach my armpits and used them. I am not asking for help with gold recovery and WILL NOT TOUCH ANOTHER ACID until I have read through this entire forum not once, but twice at least.

Back to it...My question is...What do I do know??? I could not leave the waste acid around so had to neutralize it,...when making flash paper I just poured baking soda and water into my pan after dropping paper into 2 buckets of water (only used 50ml of acid) not realizing how much baking soda would be required I placed ice and a small plastic garbage can inside of a larger one, filled the outer one with ice and water, filled the smaller one with a box of baking soda and water then poured my dirty sulfuric into it (1000ml) after half of it it stopped fizzing, I more soda and nothing....then poured in the rest of the sulfuric...no fizzing. I let it sit before grabbing some PH paper to test. After all the foam had died down I spooned a bit more soda and it fizzed like crazy...I added 3 more boxes of baking soda and still going nuts....I am out of room in my 2 cans and now when I add baking soda to the outside container IT FIZZES TOO!!! So I have a couple plastic containers on my second story wood deck and don't know how the he|| to take care of it. I already promise NOT to mess with this stuff again without a much deeper knowledge....but can someone please tell me how to take care of this before I cause some serious damage.

awaiting an answer...in the meantime will try to find it on my own.


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## Martijn (Jul 19, 2021)

Welcome to the forum. Yes you have made some big mistakes. 
You tube... :evil: 
*Wet ashing is the biggest one, only for the few highly experienced chemists imo. 

*Making Caro's acid instead of just using H2SO4, which by itself is extremely corrosive when hot!! Goes through your skin in an instant. No baking soda solution will help much there. The reaction with neutralizing baking soda-water to hot acid taking place on your skin will maybe even make it worse. 

You have started with a process that I would never attempt. Not even on a single chip to see what happens. 
Very extremely dangerous, hot peroxymonosulfuric acid. Not sure if that dissolves gold too. And what compound that would form without chlorine present. Or how to test for said gold compound in solution.. 

Neutralizing H2SO4 takes a lot of baking soda / soda ash / lye / ... , you could dilute it (pouring the acid in water while stirring) to make it pass a filter without consuming the filter. If any gold wires are left and did not dissolve in the caro's acid. How will you know it's dilute enough> test *a bit* on* a small piece* of filter paper. 

How this works with H2O2 in the mix... Don't know... need more experienced members to comment here. 

Neutralizing an acid sounds really harmless, but actually destroys the compounds that make up an acid and breaks them down into elements like gas. Harmfull gases. Chlorine gas, Sulphur gas, nitrous gas, etc.
Exept for HCL and NaOH, which form salt water when put together. 
While you could have found another purpose for the used acid, saving on money and waste. 

4 times the amount of acid compared to the chips you say? How much will that yield at the end @ 0,5 or 2 grams of gold per kilo of chips with the cost of sulphuric acid taken in account? 
Not mentioning the costs of other processes you are going to use to further refine.
Gold is worth a lot, goldfever is a recipe for bankruptcy. 

If you ever feel like trying something out for the first time, and thus have no experience with, start small. small test> smaller risks> smaller mess to fix> less waste> small loss if it goes wrong. 

And even more important> *ask here before attempting anything. *

With all the e-waste you come across with your buisiness and probably intend to process, I strongly urge you to start reading here: Dealing with Waste 

Martijn.


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## Dusty3kids (Aug 6, 2021)

Thank you Martijn....sorry for such a late response. the morning I posted my question my computer blew up (fans gave out on graphic cards...replacements came from China...I am just now back online. And so that games are not a problem I use a flip phone...lol. What I decided then to keep everything and everyone as safe as I thought I could I bit the bullet and used the 5 gallon glass water jug I use when making my 'shine'. I poured my entire solution into the glass jug, dumped my IC's into a bucket of water then took the jug out to my shed and placed a piece of wood on top (since I did not now if any of the reactions going on were giving off gas still and was afraid something might blow. I now realize...not as easy as some make it sound and have a checklist of questions I need to answer before I even start anything, though that is a long way off....I have a whole forum to read first...

Oh, and one last thing of note...I really only intend on doing this once (with several initial attempts being practice) for each component type and the pcb's, just to do it. Profit is not a concern, I want to do it best I can, but I expect to take a loss when all is said and done since I don't intend on continuing. I really only intended on doing fingers, but then got carried away in component recovery....


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## Dusty3kids (Aug 6, 2021)

galenrog said:


> YouTube can kill. Unless it is a video suggested by a longtime member, or moderator from GRF, please ask about it here.
> 
> I have noted news reports from Idaho (2) and Arizona (1) in the past year of amateurs getting advice and instructions on precious metal recovery and refining from YouTube. Two are dead. One will be soon due to organ damage.
> 
> Time for more coffee.



Just ran across this post...I am in Idaho...I am done I think....Not worth the risk for me to "just do it", going to label my glass jug and take to my local dump for proper handling. Still reading the site though, very interesting stuff.

(not sure if that is the right way to quote or post a post from a different thread, but no matter, probably won't be hearing from me for a long time if ever).


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## Dusty3kids (Aug 7, 2021)

Don't mean to be replying to myself but quick question if anyone is inclined to answer...if I really had safety in mind and did not care about any loss, couldn't I have just dumped my solution down my drain and flushed with water after a couple minutes to avoid a possible eruption when adding water to an acid. I don't ask this stupidly...the concentrated Sulfuric I used was a whole bottle of 98% sulfuric drain opener, if I hadn't used it as my solution I would have unclogged my drains with it anyway, right?


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## FrugalRefiner (Aug 7, 2021)

No!

Once you started dissolving metals in your solution, you created a very toxic solution that can kill most living organisms. It can also wreak havoc with your local waste treatment plant's system.

Always treat your solutions as toxic waste and dispose of them safely.

Dave


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## galenrog (Aug 7, 2021)

FrugalRefiner said:


> No!
> 
> Once you started dissolving metals in your solution, you created a very toxic solution that can kill most living organisms. It can also wreak havoc with your local waste treatment plant's system.
> 
> ...



Please let me add that wastes from metals recovery and refining not only have to be disposed of safely, but also in accordance with all applicable laws and regulations.

Time for more coffee.


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## Dusty3kids (Aug 8, 2021)

Thank you...I did not realize that. I am no longer pursuing this hobby actively at this time. I do VERY much appreciate the reply.


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## jadedalex (Oct 29, 2021)

I have worked with Industrial grade Sulphuric Acid in the past while an Operations Technician. Pure Sulphuric requires pure Caustic Soda for neutralization. You DO NOT want to be breathing the fumes... If your local Landfill has a toxic waste center, take it there. Like Frugal said, SAFELY. I hope the rest of you Newbies learn from Dusty's mistake...Everyone needs to understand - Acids are serious stuff that MUST be given respect, if not, then you, too, will wind up like the two people in Idaho and the fatally poisoned person in Arizona.


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## andu (Feb 14, 2022)

I had no idea HP makes sulphuric acid so terrible.
However hot sulphuric acid can dissolve some gold.


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## Yggdrasil (Feb 14, 2022)

andu said:


> I had no idea HP makes sulphuric acid so terrible.
> However hot sulphuric acid can dissolve some gold.


What do you mean by HP?


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## Yggdrasil (Feb 14, 2022)

andu said:


> I had no idea HP makes sulphuric acid so terrible.
> However hot sulphuric acid can dissolve some gold.


What do you mean by HP?
Sulphuric has the potential to be bad all the time, hot worse and as Piranha a real killer.
I assume HP is Hydrogen Peroxide.
In chemistry one need to be quite specific about the chemicals in use, even if a name is close the reaction can differ a lot.

Edit, sorry about the repetition, something weird happened during the reply.


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## orvi (Feb 15, 2022)

Dusty3kids said:


> I understand my stupidity should not warrant an emergency on your part...but.
> 
> Ok, I may be a bit long winded but I want to cover everything...First and foremost I want to say that I admit I am an idiot when it comes to this stuff apparently. I have been researching for couple of months as I can (I am a single father of 15 yr old twin boys and a 17 year old daughter and run my own computer repair business. For as long as I have been researching I have also been depopulating a storage shed full of old PCB's...I got tired of just depopulating and wanted to try to do something...so off to Youtube I go...watched some guy using sulfuric acid and hydrogen peroxide to treat the IC's and BGA's after pulling off the fiber board. So I mimicked. 4 times as much sulfuric acid (98%) as IC's and the same amount of hydrogen peroxide as IC's so 4 to 1 sulfuric acid to hydrogen peroxide. I admit now that I should have read a bit more on how to neutralize and dispose of this solution then I had as I just thought Baking soda would do it...I have made flash cotton and flash paper before but only used 50ml not 1L (oh and I did not have a bottle big enough to fit 4 times the amount of acid, I still used 4 to 1 ratio but could only manage to fit half of the required acid and only realized this after putting the sulfuric acid in the bottle, figured I was already this far let's just make it work) and was able to neutralize it easily. After heating my solution with IC's for several hours I let sit for a few then decanted what I could. Believing that gold does not dissolve in Sulfuric acid I decided it was time to neutralize what I decanted.
> 
> ...



Welcome here.

Chemistry is unforgiving, have no morales, and do exactly what it is supposed to do. Everytime. Regardless of what you expect it will do.

Process that you attempted is even more scaryier version of what is called "wet ashing process". In order to dissolve the plastic from the IC chips, hot sulfuric acid is used to disintegrate them. This process is extremely dangerous itself, not to mention *it evolves various toxic gasses arising from plastic decomposition.* It is in no means better than incineration of chips.

*Hot sulfuric acid is so corrosive, I will say it is instantly "flesh eating"*. As you added hydrogen peroxide, you added oxidizer to it - so now it is an order of magnitude worse than just hot sulfuric acid. This is called "Piranha solution", and there are plentiful videos on YouTube about it. *Mixture of hydrogen peroxide and sulfuric acid could even explode* due to presence of unstable peroxosulfuric acids.
I stick one video here issuing this "piranha solution".

To the "baking soda" issue. You must understand what is going on here, chemically, to be able to understand why using baking soda is completely unnecessary. Chemical processes are something like more advanced meal cooking. You need to follow the steps exactly, put in right things at right times and be sure that you do not have boil over 
Roughly speaking, for 50 mL of concentrated sulfuric acid, around 160 grams of sodium bicarbonate are needed to neutralize the acid (to make it "stop fizzing"). In turn, you will create sodium sulfate:
H2SO4 + 2 NaHCO3 ---> Na2SO4 + 2CO2 + 2H2O
And as there is little to no water in the mixture, it will start to precipitate out, thickening the already messy stuff, and making it impossible to do any decantation or settling.
You need to DILUTE the soup with water. But this is also very dangerous if done incorrectly.
You need to pour the acid sludge to the water, never water to the acid ! It will heat up very strongly, in some point, solution will be boiling, if any more acid sludge will be added. BE CAREFUL.

Then if there is some gold left, it will be settled on the bottom of the beaker/bucket.

*Do not forget to collect and treat your waste properly.* If you basically pour the bucket down the drain, you inevitably pollute the enviroment with heavy metals such as copper and lead. In the waste treatment plant, they can do nothing with it :/

If you want to play around and don´t want to get very much involved in chemical "stuff", i will advise you to study how to properly incinerate the IC chips. And then you can sift the ashes, and pan the ashes for gold bonding wires. Not extremely efficient, but it is easy and no boiling hot sulfuric acid is necessary.

Have fun and stay safe.


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