# Acid Peroxide Process Information Thread Q & A's



## lazersteve

The purpose of this thread is to begin to consolidate the vast amount of questions and answers related to the Acid Peroxide (aka AP) recovery process.

First and foremost, the name for the process, Acid Peroxide is a misnomer as the active ingredient is actually copper II chloride (CuCl2), so it should have been called the Copper II Chloride Etching process. Once the copper II chloride (C2C :idea: ) is formed it is reusable indefinitely if you take care not to foul the solution. Once formed all you need is air, HCl, and water to keep things going forever using the same solution. Your only problem will be the ever increasing volume of the C2C solution and it's proper disposal.

Secondly, C2C should be used primarily to remove copper from gold bearing scrap before attempting to digest the gold. If the plated scrap is magnetic (kovar or iron/steel) then AP (C2C) is not the process to use.

The last key note is that if you use too much hydrogen peroxide (3%) to initally generate your copper II chloride you may dissolve some of your gold into solution. If you think more is better and add too much too quickly or use too high of a concentration of hydrogen peroxide you will dissolve gold. The peroxide is a catalyst for the reaction, not the active ingredient. If you do this then simply keep using your AP as directed without adding any peroxide until it becomes saturated with copper and the gold will cement out on it's own. There is no need to add any other precipitants to the solution and doing so will foul the solution.

If you haven't read the Copper II Chloride etchant document on my website in the documents section now is the time to do so. You'll be light years ahead of the game as to what to look for and what the various colors of the solution indicate. You'll also have all the chemistry information you could want on the topic.

Now to the consolidation of previous Q&A's on the topic:

Learning AP: AP Acquaintance Test Setup
AP Common Facts: Acid Peroxide Notes
AP Q&A: Acid Peroxide Help
AP Cleaning Foils: Gray Powder in Foils

AP Waste: Dealing with Excess AP
Summary of AP Clean up

If you are a visual learner then you can watch the Acid Peroxide videos for free on my website or you can buy the full length DVD: Processing Finger Boards with Acid Peroxide at my *web store*, it's the first item on the list.

This post is a work in progress and will be updated as I have free time to consolidate the information scattered across the forum.

Steve


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## Pally

Hello, Steve,
I am wondering if 32% muriatic is good enough to try this method?
I have five or so pounds of board pins (mixed with solder from removal)
if i try to get the gold from these pins, will there be any problems with the solder?
I did clean much of the loose solder out of the pile....2-3 lbs.
These are the results of 100 motherboards give or take.....
Nitric acid is severely restircted in canada, im looking for a way that excudes it from the process......
Will it be ok to simply keep adding pins and keep the pot hot till they are all stripped?
What quatitiy of combined liquid would dissolve this pile of pins?
Will it strip fingers too?
(i have about 5 lbs of them too.....)
What if i keep the pot boiling after taking out the pins and simply add the finger pile?
Will all the gold precipitate out into the black powder?
One more question,
how to mix the two chemicals....?
slowly add the preoxide when cold? then heat to strip?


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## lazersteve

32% HCl is fine. 

Pins with solder will be slow going in AP, but as long as they are copper base, they will strip.

I use the sulfuric stripping cell for larger batches of pins.

Steve


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## Moo

Steve, is there any additional video included in your processing fingers dvd other then whats on your website? Also do you have a downloadable option in an iso format for purchase?


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## lazersteve

Moo,

Sorry no downloadable content. 

What other information do you seek on video?

Several of my other DVDs cover various generic refining and lab techniques applicable to all sorts of scrap.

Despite the fact that I title and sell my DVDs by specific scrap types, many of the techniques demonstrated on the various DVDs apply to a broad spectrum of recovery and refining scrap processes. The primary focus of the DVD's is the titled subject matter, but I place many gems of information among the videos.

Steve


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## goldenye

is the ap method usefull with gold filled jewellery? that usually has copper, brass, tin, lead, or silver in its core? or is this method only usefull with cpu chips and fingers?


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## lazersteve

Gold Filled is best processed using 50/50 nitric acid followed by AR on the resulting foils after filtering.

I sell a DVD on my webstore (link below) demonstrating the entire process for gold filled scrap.

Steve


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## Pally

Well yer gonna laugh i think....
I get muriatic acid from the recyclers...they give it to me for free....
The trouble may be that it doesnt store well???
Some of it is clear and fumes, and other stuff is yellowish and doesnt fume.
so much...
Anyways, i put 25 telephones into Acid with peroxide and boied for hours...2-3
The resuts were that the gold is gone from the boards but i get no yellow flakes out of the acid either....
I smashed the cell phones flat with a hammer breaking all the chips and stuff off of them before boiing.
They were flattened pretty good too....
The stuff i broke off i will treat for gold later(and other stuff too if possible)
The remaining acid must have the gold in some kind of solution as i have filtered it well and theres nowt much oin the fiters either..
I have another batch that did this too which i saved all the acids separately.....
So far i got fingers off successfully in onme batch,but notning much oin the last three using fresh acid every time too.....
How do ou precipitate the gold out?
thNKS PALLY


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## lazersteve

Processing whole boards (even if crushed first) with Acid Peroxide is frowned upon. You will likely have to cement the values (if shown to be present with a positive stannous test) on solid copper buss bar to recover the values and start from scratch with the cemented values. 

Steve


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## Pally

Hi Steve...
I didnt know about the frowned upon part....hope im not screwing up too badly here....will desist that method for beaten phone boards.........
On the other hand, i do have some 500 of them to process right now...and would like to get the gold silver and etc pout of them....this was a test....
One reslult was the boiled boards lost their surface coatings to some extent.
Two boards were actually gold plated on both sides completely, and lost the varnish...after which they lost their gold when i replaced then after scraping....
For the whole mess of phones, plus the left overs of the last unsuccessful batch(i got nothing out of that one)
I have a small amount of grey powder drying in the acid filter.....hardly a flake of gold....
And also i got the residue from the bath which is in three roughly) parts...
Black grainy remains of squashed chips....coarsest grains...
A spakly residue thats about middle wieght, and a white reside like very fine white sand, but very very smaall particles....
These are separated by tapping the bottom of my gold pan in which i panned out the varnish residues....

I take it theres two to three kilos of silver in a (cell phone /ton....)my term....so where would the silver go also?
Is it the white small particles in the pan....
(bearing in mind i am talking about a very small amount of material in a small finnishing gold pan 6 in bottom)
I have to date cooked off about four pounds of solder and pins, netting nothing, also a couple of batches of memory and cold cpu board with the fingers left on....
(But the chips cut off..i have these separated.)
25 cell phones
Thoe only gold recovered so far is the fingers i cooked first batch.
so i have a gllon + of Hydrochloric acid which i filtered out and kept in separate batches.....
can i just mix it all up and chuck a copper bar in to suck up the gold ?
if so will i also get the palladium silver and or platinium with it ?
and finally Can this off colour acid stuff be reused for more batches?
or how do i purify it or neutralise it?
I must appologise, i guess i just jumped in with both feet....i do that...
I have wrecked 200 computers and have 100 cpus waiting for nitric acid from supplier....
The steel goes to scrap
The copper also
aluminium heat sinks are valuable also...
cell phones i get for 50 cents each from a source for fifty or so a week average...
I pick up at five computer stores and three second hand stores every friday....it sort of snowballed from the watches.......
The junk gets fixed or scrapped....
i have saved some remarkable junk from time to time...
i pods lap tops, stereos, toasters...you name it...
I give aa lot of it away for the fun of it too....
also i prospect and pan gold that way....
Oh the watches?
I bought a whole tub of watches at a swap meet....thinking of blowing the plating off
But i fixed w wholebunch and now i supply three second hand stores....
they are my donations...
But i still get tubs of these things....five to date...
so have a huge stock of watches to blow the gold off of...
I realise its not all pure gold , but will refine it electrically later maybe...
You probly think i am nuts but this is just what retirement worked out for this ole logger...
though i still have a skidder(666) in the yard, im getting too old to log and the forest is worked to death here....
Anyways any info wouldbe a help...im having fun however.... :lol: 
thats enough for now...i guess....any answers would be great....
i appreciate your help in this thng...i am poorly educated in chemistry math and stuff...but capable of causing great eceological damage if left to my own ignorant designs....
Why by the way do you not cook boards?
It even took the gold plating off the two entirely goldplated boards after i scraped off the varnish bubbles....(grean icky flakeystuff)
thanks for any help in advance...
pally


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## jimdoc

Pally said:


> Hi Steve...
> I didnt know about the frowned upon part....hope im not screwing up too badly here....will desist that method for beaten phone boards.........
> On the other hand, i do have some 500 of them to process right now...and would like to get the gold silver and etc pout of them....this was a test....
> One reslult was the boiled boards lost their surface coatings to some extent.
> Two boards were actually gold plated on both sides completely, and lost the varnish...after which they lost their gold when i replaced then after scraping....
> For the whole mess of phones, plus the left overs of the last unsuccessful batch(i got nothing out of that one)
> I have a small amount of grey powder drying in the acid filter.....hardly a flake of gold....
> And also i got the residue from the bath which is in three roughly) parts...
> Black grainy remains of squashed chips....coarsest grains...
> A spakly residue thats about middle wieght, and a white reside like very fine white sand, but very very smaall particles....
> These are separated by tapping the bottom of my gold pan in which i panned out the varnish residues....
> 
> I take it theres two to three kilos of silver in a (cell phone /ton....)my term....so where would the silver go also?
> Is it the white small particles in the pan....
> (bearing in mind i am talking about a very small amount of material in a small finnishing gold pan 6 in bottom)
> I have to date cooked off about four pounds of solder and pins, netting nothing, also a couple of batches of memory and cold cpu board with the fingers left on....
> (But the chips cut off..i have these separated.)
> 25 cell phones
> Thoe only gold recovered so far is the fingers i cooked first batch.
> so i have a gllon + of Hydrochloric acid which i filtered out and kept in separate batches.....
> can i just mix it all up and chuck a copper bar in to suck up the gold ?
> if so will i also get the palladium silver and or platinium with it ?
> and finally Can this off colour acid stuff be reused for more batches?
> or how do i purify it or neutralise it?
> I must appologise, i guess i just jumped in with both feet....i do that...
> I have wrecked 200 computers and have 100 cpus waiting for nitric acid from supplier....
> The steel goes to scrap
> The copper also
> aluminium heat sinks are valuable also...
> cell phones i get for 50 cents each from a source for fifty or so a week average...
> I pick up at five computer stores and three second hand stores every friday....it sort of snowballed from the watches.......
> The junk gets fixed or scrapped....
> i have saved some remarkable junk from time to time...
> i pods lap tops, stereos, toasters...you name it...
> I give aa lot of it away for the fun of it too....
> also i prospect and pan gold that way....
> Oh the watches?
> I bought a whole tub of watches at a swap meet....thinking of blowing the plating off
> But i fixed w wholebunch and now i supply three second hand stores....
> they are my donations...
> But i still get tubs of these things....five to date...
> so have a huge stock of watches to blow the gold off of...
> I realise its not all pure gold , but will refine it electrically later maybe...
> You probly think i am nuts but this is just what retirement worked out for this ole logger...
> though i still have a skidder(666) in the yard, im getting too old to log and the forest is worked to death here....
> Anyways any info wouldbe a help...im having fun however.... :lol:
> thats enough for now...i guess....any answers would be great....
> i appreciate your help in this thng...i am poorly educated in chemistry math and stuff...but capable of causing great eceological damage if left to my own ignorant designs....
> Why by the way do you not cook boards?
> It even took the gold plating off the two entirely goldplated boards after i scraped off the varnish bubbles....(grean icky flakeystuff)
> thanks for any help in advance...
> pally



Study the forum before you proceed with any processing until you understand what to do, and what not to do. That is the best advice for you at this point. It isn't as easy as giving you an answer. You must understand the fundamentals. Hoke's book will teach you the fundamentals, make sure you read that until you understand it. The forum will teach you some more modern processes. 

Jim


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## maynman1751

It sounds like you have wasted quite a bit of material so far with nothing to show for it. Do what jimdoc suggested and read Hokes book and study the forum . you need to know and understand what you are doing or you will continue to have disappointing results.


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## Pally

Not too dissapointed so far....
I have an eightth of an ounce of finger flakes....
And who knows what all ive cemented out of my acid onto copper....still doing that...
Plus i have been doing a bit of experimenting with HCL....
It seems to take the silver plate off of spoons and such fairly well....(i just have copper left showing, and some blackish residue in the acid pickling juice...(i just have to figure how to get it out....
And so i did some golden pate spoons in another HCL bath...it lost its plate in 24 hrs...so i have that acid with some gold in it to get out too....though i can see gold floating in small pieces in it...so will filter first.....
The copper ingots with gold on em will be plated onto a pure gold piece to get a solid chuink of straight gold.
At least thats the course for now...
besides reaading up a bit morethat is....
must find out what happens when you try to get the silver out of the acid....i assume its silver chloride and im thinkin itl make chorine gas maybe...so its up in the air right npow...
maybe itl precipitate out with the aaddition of some other chemical...
anyways it sure fun doing this stuff.....


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## butcher

Pally,

Hoke's book if you are serious. 
Dealing with waste in the safety section, also reading this section may keep you out of the hospital.


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## Krmzin

Hello, Im new to this and really would like to know one question. How do I filter the gold out after the ap process? Im looking at everyones pictures and they have great filtered gold. I have done the process and at the bottom of my bucket is a bunch of grey pins after the gold has been cleaned, and a bunch of other board bits. How do i filter that stuff out so that I could just have my gold?


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## Oz

krmzin,
You need to give far more detail for you to receive a useful answer. What was the starting material (very important) and step by step how did you get it to this point (as simple as it is many have done AP wrong) would be a good start.


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## Krmzin

my apologies. I started with the usual 3:1 ratio of HCl to hydrogen peroxide. I let it sit for 2 days while in between those days I added a little more peroxide to get a better reaction. I drained the ap from the board components that the gold came from and now I can see pieces of the board I processed finely mixed in with the gold flakes. How can I remove the pieces of the board, or when im smelting the gold down could I remove the waste from the mixture? This is my first time and Im just trying this out on a few cell phones but just wanted to get the kinks out before I try on my 5 1996 and earlier computer brains.


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## maynman1751

You can dissolve the gold with HCl/Cl and then filter. This will allow the gold to pass through and the debris will be trapped in the filter.


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## robertpdickson

Guys, this whole AP process seems to be a huge waste of time and materials. Currently I'm stripping gold foil from cpus using straight Nitric acid and it works fine each and everytime. Whenever I introduce HCL and peroxide or Cl it blows up (not literally) into a green nasty solution with cemented everything in the sludge.

Please tell if I am crazy but is this AP process here not the best way to go? Not slamming anyone or trying to be rude.....its frustrating. I have a good chem background but I believe I am not good enough as some on here to use the AP process. Just looking for validation.

Thanks all and gold be with you.


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## jimdoc

robertpdickson said:


> Guys, this whole AP process seems to be a huge waste of time and materials. Currently I'm stripping gold foil from cpus using straight Nitric acid and it works fine each and everytime. Whenever I introduce HCL and peroxide or Cl it blows up (not literally) into a green nasty solution with cemented everything in the sludge.
> 
> Please tell if I am crazy but is this AP process here not the best way to go? Not slamming anyone or trying to be rude.....its frustrating. I have a good chem background but I believe I am not good enough as some on here to use the AP process. Just looking for validation.
> 
> Thanks all and gold be with you.



Nitric costs a lot more, and is harder for people to find in some areas.


Jim


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## robertpdickson

Jim, 

But it is the best way to go correct? Or at least the most likely not foul the reaction? I understand it is a bit more costly but it seems to be dog gone effective.

I believe Hoke recommends this as the first step to cleaning dirty scrap.

Thanks, Robert


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## jimdoc

robertpdickson said:


> Jim,
> 
> But it is the best way to go correct? Or at least the most likely not foul the reaction? I understand it is a bit more costly but it seems to be dog gone effective.
> 
> I believe Hoke recommends this as the first step to cleaning dirty scrap.
> 
> Thanks, Robert



The first step should be to remove as many base metals as you can, without the precious metals going into solution with the base metals. Nitric will put palladium and silver with your base metals. It depends on what you are working with I suppose.

Jim


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## Geo

AP is a "work around" method. that doesnt make it any more or any less effective than any other. this has been discussed tirelessly on the forum, the pros and cons of AP as apposed to other methods. your particular outcome may be different due to many different factors. type of chemicals, type of equipment, level of experience, even the weather plays a role.when you use nitric acid to reclaim gold foils, the nitric and the copper is consumed and converted to mostly copper nitrate. when AP is used the hcl and copper is consumed and converted to copper chloride.copper chloride when in the presence of oxygen, will etch or dissolve copper fairly quickly. when you create copper nitrate, thats pretty much the end of the line for its usefulness. copper chloride can be used over and over again which makes it more economical still seeing as hcl is SO much cheaper than nitric acid. theres much more to the back and forth but the main thing in it all is (1) AP is cheaper and can be re-used (2) nitric is much faster.


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## robertpdickson

Okay, thanks all. That pretty much clears up the mystery to me. I am not years upon years a seasoned gold refiner so I may not understand how to work with AP effectively or efficiently yet. Nitric (although more expensive) might be the newbie's safe bet and the reusability of AP does have its benefits as well.

Again, this is a great forum and help is fast and good on here!


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## Geo

Robert, that is not true. nitric acid is very dangerous and very harmful to your health. when you dissolve metal with nitric acid, nitrogen dioxide (NO2) is evolved. if you inhale this in any concentration, it will form nitric acid in your lungs by mixing with the water vapor there. nitric acid kills living cells on contact. your lungs never, NEVER, heal from being damaged by it. it is a cumulative effect, it destroys your lungs a little at a time until you are like me. i am 48 and have never smoked a cigarette in my life but i suffer from COPD caused by inhaling NO2 fumes while making nitric acid 20 years ago. now instead of looking forward to watching my grandchildren grow up, im discussing with my doctor whether or not ill make a good lung transplant recipient. nitric acid IS NOT the safest and best for beginners. besides cyanide, i cant think of a more dangerous chemical for a newbie to try and work with. 

i apologize for being so graphic, but i just want you to understand what kind of danger you are putting yourself and perhaps those around you in by using nitric acid.


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## xALmoN

Just a quick question. 

With acid Cu2+ etching, my impression is that this system is specially selective towards copper only and will not etch anything else (but what about the free acid?)

Am I right about this?


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## butcher

In the copper II chloride leached base metals lower in reactivity series will go into solution as chlorides producing copper I chloride, in the electronic scrap like with solder the tin will go into solution and lead chloride will precipitate, as will silver chloride.

It works best if specifically used for copper as this way it is re-useable and just generates more copper II chloride, but it will leach other metals into solution.


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## xALmoN

Steel does not dissolve though, or does it? i remember seeing a few posts that steel pins do not dissolve. is that because the acid concentration is high? 2M isn't all that high though, imo. Is 2M considered conc or dilute? 

I guess, a pretreatment with HCl before AP will be appropriate if other base metal contaminates are suspected to be present. Would ferric chloride affect the solution in any way other than potentially binding up Cl-? Though I dont think there's any binding up of Cl- as the salts are fully soluble.


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## butcher

If iron metal is added to a solution of copper II chloride, the iron will dissolve (or iron from the steel), this will form a solution of iron chloride, the copper will precipitate from solution as copper I chloride and or copper powder

Copper and iron can also be in this solution at the same time.

Iron chloride can also dissolve copper forming an iron hydroxide with heating.

Iron chloride cannot be rejuvenated like copper chloride can.

Steel or kovar in pins can be leached with acid peroxide, but if much iron is involved you cannot reuse the solution long, as eventually you end up with an iron chloride solution and not a copper chloride solution (which can be rejuvenated and reused if kept healthy).

Read the documents on Laser Steve's web site for a better understanding of this leaching process.


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## xALmoN

Roger that.

Those were just some preliminary questions i had to get out of the way before i continued.


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## butcher

A google search and reading about the reactivity series of metals is very helpul in the chemistry we use. 

http://www.google.com/#sclient=psy-ab&hl=en&site=&source=hp&q=reactivity+series+of+metals+&btnK=Google+Search&rlz=1R2RNQN_enUS457&oq=reactivity+series+of+metals+&gs_l=hp.12...10610.10610.1.11578.1.1.0.0.0.0.0.0..0.0.les%3B..0.0...1c.dovqlJDh174&psj=1&bav=on.2,or.r_gc.r_pw.&fp=243757dd2ec462e8&bpcl=35243188&biw=1024&bih=539


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## JesseSShaw

jimdoc said:


> robertpdickson said:
> 
> 
> 
> Guys, this whole AP process seems to be a huge waste of time and materials. Currently I'm stripping gold foil from cpus using straight Nitric acid and it works fine each and everytime. Whenever I introduce HCL and peroxide or Cl it blows up (not literally) into a green nasty solution with cemented everything in the sludge.
> 
> Please tell if I am crazy but is this AP process here not the best way to go? Not slamming anyone or trying to be rude.....its frustrating. I have a good chem background but I believe I am not good enough as some on here to use the AP process. Just looking for validation.
> 
> Thanks all and gold be with you.
> 
> 
> 
> 
> Nitric costs a lot more, and is harder for people to find in some areas.
> 
> Jim
Click to expand...


Just some information I posted earlier in another thread. Using nitric acid is of course an alternative. The decision is easier for each individual's circumstances with the proper information. I use nitric acid because this AP method is too much for me to bother with. I may try this method at a later time but for now it just seems like too much to deal with as robertpdickson suggested. Then again, I have learned long ago how to easily make and safely handle a nitric acid concentrate.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=16420&start=20#p180610


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## lazersteve

Acid Peroxide (AP) is one of many 'tools' in the refiners box. There are several situations where AP is the *best* tool, there are others where it is not. Nitric acid has drawbacks of it's own and is difficult to remove once you use too much, a common occurrence with nitric acid users. I use AP and nitric acid *both* in my refining, as well as many other useful reagents. Many people have limited resources and/or no access to nitric acid and choose AP for this reason. Others dislike the deadly BFRC (big frigging red cloud) and prefer to use chlorine. 

If your AP reaction went haywire you added too much peroxide at one time. Nitric acid will also boil over if you are too heavy handed with it or apply it to finely divide material. Regardless of whether you use AP, Nitric acid, or any other oxidizer, you must observe proper technique to get the desired results.

In my opinion AP is a great tool for working with Palladium scrap as well as many other scrap types. Choose your recovery and refining processes based upon the scrap type, as no reagent is a 'one size fits all' solution.

Steve


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## JesseSShaw

lazersteve said:


> Many people have limited resources and/or no access to nitric acid and choose AP for this reason. Others dislike the deadly BFRC (big frigging red cloud) and prefer to use chlorine.



That is why I posted the information that I did. Just wanted to share that it isn't difficult to make nitric acid provided one understands the process and adheres to the safety precautions. Knowing the dangers of working with the many corrosive and toxic chemicals and compounds being used for PM recovery is a necessity anyways. Sometimes it is better to remove steps to avoid problematic situations. There are more steps in using the AP process than in using nitric acid from what I can see. Therefore, there are more places where something can go wrong. As you said though, the application determines the process. I agree completely that the big red cloud of nitrogen dioxide is scary. It's the big invisible clouds of toxic gas such as chlorine that scare me even more lol.


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## butcher

Sometimes there are more than one way to do things, with nitric acid it is like a sledge hammer it does a good job, but it can have its draw backs, cost, deadly fumes, and if tin is involved a mess.

Copper II chloride leach (HCl acid peroxide), is also a wonderful tool, it is slower, works best for dissolving copper, it is a smaller hammer in our tool box, but sometimes the smaller hammer can be the best tool for the job, but if you learn to use it properly you will find in a very useful tool.

I cannot say one tool is better than the other, but I may pick one tool over the other for certain jobs, and which tool I pick is normally determined, by which tool I feel is best for the job at hand.


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## kkmonte

JesseSShaw said:


> lazersteve said:
> 
> 
> 
> Many people have limited resources and/or no access to nitric acid and choose AP for this reason. Others dislike the deadly BFRC (big frigging red cloud) and prefer to use chlorine.
> 
> 
> 
> 
> It's the big invisible clouds of toxic gas such as chlorine that scare me even more lol.
Click to expand...


It's not invisible to the nose! You'll know when you add too much bleach! That is the plus with using the AP solution, both HCL and CL fumes are very noticeable. I haven't worked with Nitric yet, but I know NOX fume breathing is cumulative. (Not sure if its the same with HCL or CL). Like you said, there are alot of deadly things we use and need to be careful with using them all. Most of them can kill you if used incorrectly, some faster then others. To each its own I guess.


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## JesseSShaw

Yup, it all depends on the circumstances for which method is best suited for the job at hand. I agree completely. Nitric oxide gases have a definite odor and a "biting" sensation when inhaled because it reacts with the water in your lungs. Also, The gas has a dark-red/deep-maroon and dare I say pretty color. It is the not so noticeable toxic gases that I am more fearful of. Nitrogen oxides are definitely very toxic like many gaseous elements and compounds. I am sharing information on how to make nitric acid for those who do not have easy access to it or who have never considered using it for whatever reason. I am seriously considering writing a tutorial that details how to make nitric acid easily and safely and posting it in the tutorials section if it hasn't been posted already. All in all, I will eventually try the AP method when I have completed my current projects and I can get around to experimenting with it.


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## butcher

Not all NOx gases are visible, and some are hard to detect, with your nose.


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## JesseSShaw

I have to assume you are referring to nitric oxide.
here:
http://en.wikipedia.org/wiki/Nitric_oxide

On a side note, I just made another batch of nitric acid. Using 70ml of sulfuric acid and 100g of sodium nitrate, my yield was 37ml of 86+% HNO3 (concentrated nitric acid). Sometimes I double up on the reactants in a larger reaction flask (1000ml) for double yield. I usually have enough for whatever process I need it for. After I have used this batch then I will experiment with this AP method.


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## Axl_Bundy

First time poster here, lol.

Can I store old AP solution in an air tight container like a old pickle jar? I will reuse it but want to store it safely for now.

Take care
Ian


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## Claudie

I don't store anything in a container that was originally for food, just to avoid confusion, plus it will eat the metal lid away.


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## Axl_Bundy

OK, but can I still store it in an air tight container? (plastic bottle and plastic lid)
It won't explode or anything will it?


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## Claudie

You can store it in the plastic jug that it came in, just be sure to label it so you know what it is.
Read what Butcher wrote in this thread: 
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=16882&p=170803&hilit=storing+AP#p170803


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## jonn

Quick question on making AP from coppers oxide. 
I calculated the ratio as 150 grams copper oxide,
370 ml hcl 32%
700 ml H2O
It made a nice emerald green color almost instantly and became slightly warm. Is my math correct please? Thanks, Jonn


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## butcher

Jonn, 
I could calculate it weights and volumes using molarity from the formula, but I do not see any need to go to the trouble, if you added HCl to copper oxide you would get copper chlorides, either copper II chloride, or copper I chloride, if both are in solution you will have a very dark brown solution with possibly some remaining white copper I chloride powders, a little more HCl and it will turn the emerald green color you see now the copper II chloride is the green,(I believe the oxide from the copper oxide has also helped, where you didn't need to add oxygen).

From your description you are just fine with that green copper II chloride, it should be ready to dissolve more copper into solution.


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## jonn

Hi Butcher, how are you friend? Thank you for the perfect explanation. I realize now I forgot to add HCL to bring my acid concentration molarity up to 3.0. Figure I was at .7 when the minimum is 1.0 and the maximum 3.5. It's amazing how fast AP works from copper 2 oxide compared to copper metal and H2O2. Thank you Lazersteve for the document link  
It was too soon to add the bubbler as after only hours the white copper chloride powder caked the bottom. Anyhow, I added HCL to bring my concentration molarity up to 3.0. The copper chloride redissolved and theres gold flakes like glitter in the sun :lol: I see now the solution should have been left unbubbled, allowed to react all copper metal, filter off the gold, then add the bubbler, dropping the copper chloride powder, filtering and the AP is ready for reuse. Totally amazing :mrgreen:


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## yar

Still studying but focusing a lot of attention on the AP process. What I have gathered is that AP solution will increase in volume the more times it is re-used. My question is has anyone gotten to the point where they have a large amount on hand and instead of neutralizing and properly disposing, can AP be separated into smaller quantities and be re-used ?
For example if you have 10 gallons, can that be poured into four 2.5 gallon lots and be continued to be re-used ?


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## lazersteve

Yes. Use as much as you need and properly dispose of the rest. Copper Chloride (I and II, aka: acid peroxide) have many chemical uses.

Steve


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## yar

Thank you Steve.


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## Feenixb1o7

I have been mixing my own 3% solution of hydrogen peroxide, I've been mixing 42ml H2O2 (35%) with 458ml water to make 500ml at 3% my question: When topping up an acid peroxide solution for foils, is adding JUST the 42ml at 35% the same as adding the 3% seeing as my solution is sealed so no water is lost, just the peroxide. 
So surely I can just add new peroxide right? Otherwise my solution keeps building up, it started at around 300ml and is not close to 800ml.


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## FrugalRefiner

Peroxide is only needed when you start a fresh batch of acid/peroxide. After that, you should rejuvenate your solution with a simple aquarium pump bubbling air into the solution. Air doesn't add any volume to your solution.

Dave


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## Feenixb1o7

I don't have one unfortunately, though I think I have an old compressor laying about somewhere.


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## scranney

I am still learning on refining and have been reading the forum a lot and watched steves videos.
I have about 500g of gold fingers from ram and pci boards trimmed so I am planning on doing then in the ap solution then using the bleach and hci. But I have some concerns.

My questions are.

1 if I use an air bubbler in the ap solution I will need to keep it close to my house. Will the fumes from the ap start to corrode my tin roof and gutters?

2 It does get above 40°C sometimes. If the ap gets too hot will it disovle gold?

3 do most of you just keep your ap solution in the backyard while disolving the copper from fingers or where do you normally do it if not?

Great forum everyone. Thanks

Steven


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## butcher

Steven,
The copper II chloride will have less fumes than the bottle of HCl does when you open it, but most any of the reactions we do produce fumes, and at times spills (catch basins are needed), any metal in the vicinity is subject to attack, tin (zinc coated steel), the zinc coating a very reactive metal, subject to attack from any of these acidic fumes, the zinc in your roof will suffer from attack of these acetic fumes, many of which when they encounter moisture in the air form acids of those fumes.

Even though the copper II chloride (AP) process is a lower fume producing procedure, you will not want to use it in your home, garage, or tool shed, or where you have metal that can be damaged, many of the processes we use are even worse, as far as producing fumes which are deadly and terribly corrosive, you need to have an area to work safely.


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## kurtak

butcher said:


> Steven,
> you need to have an area to work safely.



What butcher means by that is that to do "any" of this you really need to have a fume hood & scrubber set up - fume hoods & scrubbers that work can be made rather cheap & easy

Kurt


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## Geo

HCl fumes are heavier than air so things lower than the roof should be effected more. If you are using less than a gallon of AP at a time, outside in the back yard where the breeze can get to it should not pose too much of a problem. It's not the heat that makes AP dissolve gold but rather the peroxide in the AP that will dissolve gold. I would suggest that you create copper(II) chloride by dissolving some bare copper (such as wire) first until you get a nice green solution. You can then use this filtered solution with an air pump to process your fingers without dissolving any gold.


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## scranney

Thanks for your answers.
for a srubber if I am only using the copper chloride 11 and hci and bleach. Will activated charcol be ok? I saw a guy who made one on the forum using that.

Also do you clean and wash the fingers with anything special first before going in the copper chloride solution as mine are quite dusty and dirty.


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## solar_plasma

scranney said:


> Also do you clean and wash the fingers with anything special first before going in the copper chloride solution as mine are quite dusty and dirty.



You don't want to work without gloves, do you? Use gloves ALWAYS when working with poisonous salts! It isn't only to prevent getting burned, but it is not pure copper chloride, you are working with! It is definately nickel (cancerogen, allergen), too, and depending on your material, you have to expect lead (dirty material/from solder), cobalt and beryllium (alloyed pins).


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## scranney

Sorry I ment washing the gold fingers. Not the fingers on my hands.


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## solar_plasma

:lol: sorry, my fault.

Some do, others don't. I think it depends on what kind of dirt it is and how much. Since it is no greater pain to give them a wash, it wouldn't be wrong.


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## Geo

Dirt and dust poses no problems but oil does. If the fingers are oily, wash in some warm water with dish soap. Rinse well before putting them in AP.


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## scranney

That was quite funny.
Thanks.

Do you think that putting activated charcol in the scrubber is fine for the ap solution and the hci and bleach?


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## jason_recliner

Geo said:


> If the fingers are oily, wash in some warm water with dish soap. Rinse well before putting them in AP.


Or just wear gloves. :lol:

Edit: Ug, joke already been made. :|


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## Geo

Ahhh. I get it. :lol: Walked into that one backwards.


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## solar_plasma

Ok, I am not an expert in scrubber systems, but since no one else answers:

HCl vapors and clorine gas. 

Activated carbon alone will hold them more or less for a comparably short time, but you don't know, when the filter has its break through.

Both would react with lyes, which can be monitored by pH. But chlorine will form hypochlorite, which again will release chlorine, if the solution ever would get acidified. Just something to have in mind.

On the other side, chlorine can be used to oxidize iron II chloride to iron III chloride, which again is nice for dissolving basemetals. I don't know, if this is practical. But this is, what I would use chlorine for, if I had a lot of it dailly.

There has been written a lot about scubbers, I am sure, if you search deep enough, you will find more and better information.


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## Geo

If you plan on using nitrates of any kind, you should rethink charcoal. Those are two of the major ingredients for gunpowder.


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## solar_plasma

And activated carbon is useless for scrubbing NOx.


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## solar_plasma

For me it is most practical to catch gasses in a closed system in the next vessel with a matching reagent before letting them pass through the fume hood.

Another important point is, you should always use small increments of hypochlorite at a time when dissolving gold, added with a pipette at the bottom of the solution, so if you do it right, there won't be much chlorine left over, that can escape.


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## scranney

Thanks for all the help


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## Bretl

Hello my name is Bret I don't know if this is the correct place to put this and it may be posted already as I am new to the forum and would like to make sure that people do not use acetone(ketones) to strip the grease off scrap parts when using acid and peroxide it can create a very explosive compound that is heat and shock sensitive thanks and I hope this helps someone


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## saadat68

Hi
Some people here, said tin go to AP solution in form of stannous chloride and some people said tin oxidize in AP solution and produce tin oxide. Maybe both?!

1- Which is correct? ( I think tin oxide is correct because when we produce stannous testing solution, we must keep it out from air )
2- If tin in AP produces tin oxide, is it SnO or SnO2?

Thanks


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## butcher

Tin with HCl 
Sn + 2HCl --> SnCl2 + H2
stannous chloride and hydrogen gas

But we are not discussing dissolving tin in HCl, But the oxidation of tin in a copper II chloride solution.

Sn + CuCl2 = Cu + SnCl2

The tin dissolves as stannous chloride while it reduces the copper ions to metal.

The tin salt can reduce many metals (including your gold as colloidal gold).
2AuCl3 + 3SnCl2 -->3SnCl4 + Au (colloidal)

Now from here, we can get into many different reactions depending on conditions...

SnCl2 + CuCl2 --> SnCl4 + CuCl
SnCl2 + 2CuCl -->SnCl4 + 2Cu
SnCl2 + 2FeCl3 -->SnCl4 + 2FeCl2
SnCl2 + H2O --> Sn(OHCl) + HCl
6SnCl2 + O2 + 2H2O --> 2SnCl4 + 4Sn(OH)Cl

well, we could keep going as we get many reactions so many of which become several become very complicated, and all conditions of solution really dictates the different reactions.

Tins chemistry is complex enough in pure solutions or reactions, but more complicated as the solution also becomes a more complex ionic soup of metals and acid, and the conditions (external and internal) of the soup itself change in its chemistry and conditions also dictate the oxidation state of the tin ions...


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## bengie84

Morning guys and girls

So this morning gone to do some filtering opened up my 3gal bucket to find a good layer for of oxidised copper on to floating green in my AP which until now I been using for around 4 months 
So my question is has anyone else ever had this and how do I proceed to either clean the solution without fouling it to be able to reuse it or is it time to treat and dispose of it 
Cheers ben


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## kernels

Adding some fresh HCl should clear it up, try it on a small sample first to confirm.


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## torch01

Steve thanks for the wonderful tutorial. You write that AP can be used indefinitely if carefully used. I come across scrap that is suitable for AP occasionally. Can I just process material in the AP as I receive it but leave the gold in there until I have an amount that I want to take to the filtering stage? And also can I leave the gold in there even during the copper removal from the AP stage? Thanks, Wayne.


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## g_axelsson

torch01 said:


> Steve thanks for the wonderful tutorial. You write that AP can be used indefinitely if carefully used. I come across scrap that is suitable for AP occasionally. Can I just process material in the AP as I receive it but leave the gold in there until I have an amount that I want to take to the filtering stage? And also can I leave the gold in there even during the copper removal from the AP stage? Thanks, Wayne.


Yes.. and don't know.

I run copper chloride that way. Add fingers when I get them, remove any that is cleaned and the foils accumulate at the bottom.

Indefinitely is a point of view. You need to add fresh acid sometimes and sometimes water. The volume will grow over time to hold all dissolved copper. Eventually you will reach a point when you have to pour off some of it. Take that overflow and process for copper and waste, that will leave the main leach working as long as you like.

I don't know what you mean with "copper removal from the AP stage", for me I recover the copper when I process the waste, not a minute before that.

When you are ready to process the gold foils, pour off the majority of the copper chloride and store it properly until next time you want to use it. Then process any gold left in the bottom of the beaker.

Göran


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## torch01

Thank you Goran. That helps a lot.


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## bengie84

Hey guys so for past few months had no issues with my Ap now all of a sudden it’s started foaming quite bad trapping gold foils in it and sticking them everywhere is there anyway to prevent the foaming or is that it the solution 
Thanks again guys


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## lazersteve

Sounds like you may have added a different type of muriatic acid, possibly the fume safe variety.

Another possibility is that one of your types scrap you process introduced another chemical in the mix which caused the foaming. 

Foaming to me also sounds like addition of excess iron to the AP solution, especially if it is rust colored foam. 

In the above cases you may be able to save the batch of AP by filtering out the foam along with removing any solid pieces of iron that may be in there. Once you have eliminated the source of the foaming reaction, freshen up the AP with a good dose of fresh muriatic acid followed by the water test (white cloud indicates copper saturation). If you see the whitish gray particles when water is added, them add more O2 via bubbler or peroxide to bring the AP back to a transparent green color as opposed to dark black/brown.

Steve


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## bengie84

Thanks steve 
All scrap is the same I have not purposely added any iron and was carful when checking what went in the liquid is still green but very dark and the foam is also green to white as for the acid it all came from one 5lt (uk gallon) bottle but I will try and skim off the foam and filter see if that helps at all


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## Kubik_Rubik

Hello, I am extremely grateful for this forum.
I have limited access to pure nitric acid, so I save it for silver recovery. I've already used AP solution to process gold fingers, but I have a lot of relay contacts that are on a piece of copper or brass base. Many of the contacts also contain palladium. Because I would like to save nitric acid for processing the contacts themselves, can I use an AP solution to remove the base metals? I would just use a little H2O2 and a bubbler. Is there a danger of dissolving silver and palladium in the solution? I read a lot about AP, but I didn't come across this.
Thank you very much for the advice.


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## Martijn

Here is a recent thread about contact points:
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=29529&p=310631&hilit=Silver+Contact+points#p310393


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## Kubik_Rubik

Thank you. I missed that thread. So I'll continue there.


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## Outlaw72

Once your AP is used up, I see most people add in a piece of copper to cement out any PMs that might be leftover or trapped in solution and as a first step in waste treatment. Do most people save up this cemented out material, and process it again with AP to ensure gold and other PMs haven't been left behind? Just curious as I have never done these steps yet, but plan to in the future once I feel comfortable with the processes.


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## Martijn

Yes they do once they have 'enough' worth processing. That's the reason we have a stockpot. We recover and stock our missed traces of pm in there. The moment when to do it is a personal choice. And how patient you are :wink: 

AP can be reused for ever. If 'used up', just add a splash of HCL and air. Eventually you will have more than you need. 

Treating it like in the stockpot can cement out some Pd that does dissolve in AP. The 'AP' or Cu2Cl in the stockpot can also redissolve some Pd. Silver traces i'm not sure about. 
But as far as i know, no other PM's will dissolve in AP. Make sure there is not too much free HCL left. It will consume more copper first. 
Stockpot black powders can contain traces of gold and PGM's.


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## Outlaw72

Thank you, I couldn't find anything on the leftover material, probably due to the fact that trained refiners don't lose much if any gold in there waste solutions. I'm just trying to find as much information on AP as possible because it's probably the method I'll be using once I feel comfortable with everything. Another question I'm having a hard time finding an answer to is, what happens if too much peroxide is added. I have seen in different places, and posts people using a 3:1 ratio, some a few drops, and others a splash. If too much was used, you would lose gold in solution?


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## Shark

To much peroxide and AP (Copper II Chloride) will start dissolving gold. With an excess of copper the gold will cement back out over and over until the solution is saturated or the base metals are fully dissolved. 

The real reason you don't need an excess of peroxide is that your not using acid and peroxide as a chemical mixture. Your using the two to create another (single) chemical, copper II chloride, which is the actual etchant. AP can be created without the peroxide, it just takes a little bit longer to do as the hydrochloric acid must then get its oxygen from the surrounding air.


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## Outlaw72

Thank you guys for the quick responses, part of my learning is reading about the issues others are coming across and learning to fix them before ever starting my own processes. That way I'll have it in my notes if it should happen to me. Reading material like Hoke has it's uses for me, but to be honest a lot of it doesn't stick because I haven't seen these reactions and processes in person, and constantly need to revisit and reread parts of the book to remember certain things she explains. I have found this forum very useful as I move towards my attempt at a new hobby that I have a lot of interest in.


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## Martijn

Leaving copper (cemented or filings) wet and open to air will create alot of copper oxide which will dissolve fast in HCL. Quick way to get it started. No H2O2 needed.


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## dpgold

lazersteve said:


> The purpose of this thread is to begin to consolidate the vast amount of questions and answers related to the Acid Peroxide (aka AP) recovery process.
> 
> First and foremost, the name for the process, Acid Peroxide is a misnomer as the active ingredient is actually copper II chloride (CuCl2), so it should have been called the Copper II Chloride Etching process. Once the copper II chloride (C2C :idea: ) is formed it is reusable indefinitely if you take care not to foul the solution. Once formed all you need is air, HCl, and water to keep things going forever using the same solution. Your only problem will be the ever increasing volume of the C2C solution and it's proper disposal.
> 
> Secondly, C2C should be used primarily to remove copper from gold bearing scrap before attempting to digest the gold. If the plated scrap is magnetic (kovar or iron/steel) then AP (C2C) is not the process to use.
> 
> The last key note is that if you use too much hydrogen peroxide (3%) to initally generate your copper II chloride you may dissolve some of your gold into solution. If you think more is better and add too much too quickly or use too high of a concentration of hydrogen peroxide you will dissolve gold. The peroxide is a catalyst for the reaction, not the active ingredient. If you do this then simply keep using your AP as directed without adding any peroxide until it becomes saturated with copper and the gold will cement out on it's own. There is no need to add any other precipitants to the solution and doing so will foul the solution.
> 
> If you haven't read the Copper II Chloride etchant document on my website in the documents section now is the time to do so. You'll be light years ahead of the game as to what to look for and what the various colors of the solution indicate. You'll also have all the chemistry information you could want on the topic.
> 
> Now to the consolidation of previous Q&A's on the topic:
> 
> Learning AP: AP Acquaintance Test Setup
> AP Common Facts: Acid Peroxide Notes
> AP Q&A: Acid Peroxide Help
> AP Cleaning Foils: Gray Powder in Foils
> 
> AP Waste: Dealing with Excess AP
> Summary of AP Clean up
> 
> If you are a visual learner then you can watch the Acid Peroxide videos for free on my website or you can buy the full length DVD: Processing Finger Boards with Acid Peroxide at my *web store*, it's the first item on the list.
> 
> This post is a work in progress and will be updated as I have free time to consolidate the information scattered across the forum.
> 
> Steve


Hi I am confused about this, is AP HCL plus H2O2 ? If so peroxide is H2O2 ? Where does the CuCl2 come from? I am a beginner, thanks. Also if somehow I added too much 3 percent H2O2 and gold will cement on copper how do I correct this problem?


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## Yggdrasil

The AP process is not an Acid Peroxide leach actually. 
It somehow was named so because most started this leach by adding a cap or two with peroxide to HCl 
to create some Copper (I) Chloride to jump start the process, a Copper Chloride leach which it actually is. 
In fact HCl do not dissolve copper by itself. 
But Copper II Chloride etch the Copper to Copper (I) Chloride which in turn dissolves in HCl creating more Copper II Chloride and so on.
If you, as Martijn, says just sprinkle some HCL onto Copper and let it sit for a few days/weeks until its green, 
you can put it into HCl and you instantly have Copper2Chloride leach. 
Or wait until the Oxygen in the HCl reacts with the Copper. 
Most of us don't have that kind patience, so we just use an air bubbler.


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## Martijn

It is confusing indeed. 
We use the term Acid Peroxide for the cupric chloride leach, also used in etching copper traces in circuit boards. 
It is in fact the cupric chloride that does the work. 
Hydrogen peroxide, H2O2, is added to hydrochloric acid, HCl, to start the first digestion of copper into cuprous chloride, CuCl1.
Then the cuprous chloride reacts with oxygen and free HCl to form CuCl2.
H2O2 or air can be used to supply the solution with oxygen for this conversion. 
When CuCl2 reacts with copper, it creates CuCl1. And it starts over again. 

Please use the search function from this site to look up info. Trust info from older members in general. 
Use google to search for chemical info and names. Wikipedia for elements and compounds is what I use most. 

The questions you ask indicate you should stop experimenting and study what you are doing. Then present your plan here for us to review. 

Martijn.


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