My first AP, check my math?

[Captobvious]

Hey guys, just started my first AP process on a batch of fingers. Now according to everything I've read (Hokes, here, and elsewhere) the math for AP is 4:1 HCL to H2O2 yes? This batch of fingers was probably around 5 lbs (digital scale is on order) I have them in a 2 Gallon bucket (with strainer holes drilled in the bottom and about a 1/3 of the way up the sides) inside of a 5 gallon bucket. I applied 2 gallons of HCL and 8 cups of H2O2 (16 cups to a gallon) and have a 10 gallon fish aquarium air pump applying constant air to the mix. I also added a couple of copper heatsinks to get the reaction started. Now I'm assuming that the reaction I got after applying the H2O2 was normal but not sure because everything I've seen and read on the AP method is that the liquid should be green. That said when I applied the H2O2 to the HCL it immediately turned a bright yellow color. After monitoring it for about 15 mins the color did start to change to a more muddy greenish yellow color so again unless someone more experienced tells me otherwise I'll just assume this is normal for a fresh batch of AP.... but is it normal?

 

[butcher]

Captobvious

I am not sure about your math, it does sound like more peroxide than I would use in the beginning, also it should only be 3% hydrogen peroxide and 97% water, (more concentrated like 30% would put gold into solution with other metals), these fingers were they trimmed from the rest of the memory? If you put in whole memory you would end up with a mess caused from tin in the solder, and if you put gold into solution with tin it would cause lose of gold in colloidial solution, the yellow could have been gold dissolving, which you do not want to happen, if your peroxide was not too strong it would form black powder as the copper replaced gold in solution, and even if you used strong peroxide the copper heat sinks would probably be plated with gold, problem here is if this is what happened you would now have to dissolve the heat sinks to get all of your gold back, (too much or especially too strong of a peroxide will put gold into solution), No reason to add copper like copper heat sinks to the batch, all that is going to do is use up HCl and peroxide to dissolve that copper, there was already enough copper in the close cut memory fingers to make the copper chloride solution.

Sounds to me like you made at least a little mistake, but we need more details, to see if it could be more of a big mistake.

The copper heat sinks were a mistake (which may not be too bad, unless the hydrogen peroxide was too strong).
How strong was the hydrogen peroxide used?
Were the memory fingers trimmed from the rest of the memory circuit board, so only gold plated copper was added to solution, and so no that solder was introduced in solution?

 

[Captobvious]

Captobvious

I am not sure about your math, it does sound like more peroxide than I would use in the beginning, also it should only be 3% hydrogen peroxide and 97% water, (more concentrated like 30% would put gold into solution with other metals), these fingers were they trimmed from the rest of the memory? If you put in whole memory you would end up with a mess caused from tin in the solder, and if you put gold into solution with tin it would cause lose of gold in colloidial solution, the yellow could have been gold dissolving, which you do not want to happen, if your peroxide was not too strong it would form black powder as the copper replaced gold in solution, and even if you used strong peroxide the copper heat sinks would probably be plated with gold, problem here is if this is what happened you would now have to dissolve the heat sinks to get all of your gold back, (too much or especially too strong of a peroxide will put gold into solution), No reason to add copper like copper heat sinks to the batch, all that is going to do is use up HCl and peroxide to dissolve that copper, there was already enough copper in the close cut memory fingers to make the copper chloride solution.

Sounds to me like you made at least a little mistake, but we need more details, to see if it could be more of a big mistake.

The copper heat sinks were a mistake (which may not be too bad, unless the hydrogen peroxide was too strong).
How strong was the hydrogen peroxide used?
Were the memory fingers trimmed from the rest of the memory circuit board, so only gold plated copper was added to solution, and so no that solder was introduced in solution?

My apologies for missing a few details, I used 2 gallons 32% muriatic acid and 1/2 gallon (8 cups) 3% Peroxide. All fingers were as closely trimmed as I could get with hand shears but yes all trimmed. I want to link to the thread here but, but in it, it was recommended to put a little copper into a fresh batch of AP to get the reaction started hence the heatsinks, if it was an unnecesary step I'll just not do that in the future. Also I checked this morning and it was a nice emerald green color but I didn't have time (running late for work) to pull the inner bucket out to investigate further.

 

[FrugalRefiner]

I want to link to the thread here but, but in it, it was recommended to put a little copper into a fresh batch of AP to get the reaction started hence the heatsinks, if it was an unnecesary step I'll just not do that in the future. Also I checked this morning and it was a nice emerald green color but I didn't have time (running late for work) to pull the inner bucket out to investigate further.

Captain,

The AP process is actually a copper II chloride etching process. HCl doesn't do a very good job of dissolving copper, but it will dissolve oxidized copper. If you simply put clean copper into HCl, it won't do much. When you add hydrogen peroxide, the H₂O₂ oxidizes the surface of the copper, and the HCl can then dissolve it. So the H₂O₂ simply "kick starts" the reaction. Copper II chloride is capable of dissolving metalic copper, so once you have some in your solution that's what keeps the reaction going.

The problem that can happen when starting a fresh batch of AP is that the H₂O₂ can also dissolve some of your gold into solution, especially if you use a lot or if it's a high percentage H₂O₂. You will eventually recover this gold as the solution becomes saturated with copper, as the dissolved gold will cement out of solution and be replaced with copper, a more reactive metal. But it will be a fine black powder among the other solids found in the bottom of the AP bucket instead of nice big flakes.

This is why some people start a fresh batch of AP with a little copper before they add their gold bearing feedstock. It ensures that the H₂O₂ is consumed digesting copper, not their gold. Once the H₂O₂ is consumed, the copper II chloride will only digest copper, not gold.

Now that you have a batch going, you won't have to worry about it in the future. The AP is reusable, so you can just recycle it for future batches.

Dave

 

[Captobvious]

This is why some people start a fresh batch of AP with a little copper before they add their gold bearing feedstock. It ensures that the H₂O₂ is consumed digesting copper, not their gold. Once the H₂O₂ is consumed, the copper II chloride will only digest copper, not gold.

Now that you have a batch going, you won't have to worry about it in the future. The AP is reusable, so you can just recycle it for future batches.

Dave

Ok cool, I had a feeling I skipped a step, this would apparently be it but at least any that got dissolved is still there so no loss yay

I'll try to post some pics tonight if I have time

 

[Captobvious]

Think there's something wrong.... when I came home from work and finally got time to check on things this is what I found....

Much clearer than I had anticipated, but the smell of HCL was still quite strong and the couple drops that spilled on the floor fizzled as normal on the concrete, so I don't think it's lost it's acidity

Again not what I expected, mind you it's been less than 24 hrs since I set this up but I would expect the heatsink to be gone by now at least /confused

Once I lifted and dropped the bucket a few times the mix got much darker, almost black. Keep in mind this is Omaha and it's an uninsulated garage I'm working out of and it's anywhere from 20 deg to 40 deg F so I guess that could be slowing things down.

Would you guys recommend leaving it alone to bubble (had to reposition the air line so it would hold at the bottom as it was floating on top when I checked on it a few minutes ago), add more HCL (don't think this is it as the acid is still fairly strong although I have no way to test just yet as I wasn't expecting to have to PH balance this process just yet), or add more H202?

Please feel free to laugh, cry, whatever, just be honest please

 

[Geo]

im confused, or should i say, your confused. please tell us why you have a large piece of copper in your AP solution. that is copper, right? maybe you misunderstood the directions when using AP to strip foils.

point being, you do not need to add copper. theres plenty of it under the gold foils.

 

[Captobvious]

im confused, or should i say, your confused. please tell us why you have a large piece of copper in your AP solution. that is copper, right? maybe you misunderstood the directions when using AP to strip foils.

point being, you do not need to add copper. theres plenty of it under the gold foils.

That was the earlier mentioned copper heatsink I used to start the reaction last night, it has since been removed when I went to check on things tonight.

 

[kkmonte]

Your muriatic acid that you are using, its not the "safe for the environment" stuff is it? I've been doing my fingers in my barn which has been in the same 20-40 range you speak of, it adds a little bit of time but with the bubbler, that should almost negate that. That is a real lot of fingers (5 lbs) in one batch so you are going to need to agitate/shake up the fingers every so often to get the ones in the middle to go out and play with the acid. When you pull the bucket in and out of the water that will mix up all of the acid/peroxide, etc.

I also found it best that I just drop my bubbler in the inside bucket (the stone goes an inch or so under the acid) and let it bubble inside with the fingers. I tried putting it underneath the inside bucket and that never worked well for me.

Ken

 

[Geo]

i may be wrong but i think Dave meant to just have copper chloride solution to start the process and not necessarily to add a piece of copper with the fingers. if you dont have any pregnant leach, you can make some by dissolving a piece of copper in AP solution. by adding the copper with the fingers, it may deplete the hcl before the process is finished OR saturate the solution with copper which will cause copper(I) chloride to precipitate.

 

[Pantherlikher]

Hi...
Looking good as long as copper bus bar is out and rinsed...
Now most important part ya'll be a missin...
PATIENCE...please...
Agitate in the AM before work... and often when you get home and feel impatient... lift..let settle back, lift, let settle back... And look for Gold specks...
All ya can do is wait...
My guess is you over done did it a tad with Peroxide as I've been reading to add alittle at a time untill color change...but no problem there either...

BS.
If patience was worth it's weight in gold, we'd all be broke...

 

[Captobvious]

Your muriatic acid that you are using, its not the "safe for the environment" stuff is it? I've been doing my fingers in my barn which has been in the same 20-40 range you speak of, it adds a little bit of time but with the bubbler, that should almost negate that. That is a real lot of fingers (5 lbs) in one batch so you are going to need to agitate/shake up the fingers every so often to get the ones in the middle to go out and play with the acid. When you pull the bucket in and out of the water that will mix up all of the acid/peroxide, etc.

I also found it best that I just drop my bubbler in the inside bucket (the stone goes an inch or so under the acid) and let it bubble inside with the fingers. I tried putting it underneath the inside bucket and that never worked well for me.

Ken

Ken, I know for sure it wasn't the "safe" muriatic as I've seen that discussed here before as being impure, if anyone remembers the deal Home Depot had a month ago for the 2 pack of 1 gallon containers that's what I'm using. Would you recommend reducing the mount of fingers I have in there for now?

i may be wrong but i think Dave meant to just have copper chloride solution to start the process and not necessarily to add a piece of copper with the fingers. if you dont have any pregnant leach, you can make some by dissolving a piece of copper in AP solution. by adding the copper with the fingers, it may deplete the hcl before the process is finished OR saturate the solution with copper which will cause copper(I) chloride to precipitate.

Correct, the Copper was intended to merely start the reaction and as I was running late for work this morning I didn't have time to remove it until tonight. Admittedly I tried to unintentionally shortcut things by mixing it all with the fingers in place, and then became paranoid I was going to be dissolving gold before the reaction could get started so I tossed the copper in to get things going.

Hi...
Looking good as long as copper bus bar is out and rinsed...
Now most important part ya'll be a missin...
PATIENCE...please...
Agitate in the AM before work... and often when you get home and feel impatient... lift..let settle back, lift, let settle back... And look for Gold specks...
All ya can do is wait...
My guess is you over done did it a tad with Peroxide as I've been reading to add alittle at a time untill color change...but no problem there either...

BS.
If patience was worth it's weight in gold, we'd all be broke...

That's kind of what I was thinking too, I mainly wanted to make sure and double-check here as I don't recall ever seeing an AP mix that was that clear before in pics/vids I've seen. I just checked on it a little while ago and it was no longer the dark color in the last pics but again that very light green color in the first pic.... although as stated I've not seen a fresh/early batch, but only ones that have been bubbling for a few days or so.

 

[Captobvious]

Also when I checked on it last night before I went to bed the reaction was going strong, dark green color, bubbling away, and the vapor/bucket/liquid was noticeably warm. This morning and tonight they were at ambient temps.

Also I feel I have not been totally honest as I was a bit embarrassed that this happened (feel free to mock me I deserve it) but when I initially put in the copper last night at the time I could only find heat-sink that was half copper half aluminum. When I put that in the reaction was quite violent, lots of fuming, acid became incredibly agitated from the reaction. I immediately pulled that out but I do worry that the reaction with the Aluminum may have had an adverse reaction to the mix. Yes I feel stupid, yes feel free to laugh.

 

[kkmonte]

I'm LOL'ing right now! It's funny, when I was reading your post, the thought crossed my mine "Hey I wonder if he put in a heat sink with aluminum on it", although i'm still a newb so I don't know what that would do to the reaction, etc.

 

[jmdlcar]

Is the brand you using the Smart brand is the you want? Cause they sell two kinds of Muriatic Acid.

Jack

 

[Captobvious]

Note to self... get Muriatic from Lowes from now on (the jug on the left) and not the Homely Despot... turns out the two pack was the "smart" variety *bangs head on desk repeatedly* The thing is I distinctly remember looking out for the "Smart" type, found an open box of the 2 packs (only had one jug in it so I didn't grab that box), and it wasn't the Smart brand and nothing mentioning it on the box... I'm feeling real stupid now.... does Home Depot have two types they may have in a two pack box that looks the same from the box?

Welcome to the Captobvious comedy hour! Hope you enjoyed the show

 

[Geo]

20° Baume is what your looking for. really, thats all that matters. ive used the green label for AP and it worked just fine. its the "safer" brand from Lowe's. the brand name is unimportant as long as its 20° Baume.

 

[Captobvious]

20° Baume is what your looking for. really, thats all that matters. ive used the green label for AP and it worked just fine. its the "safer" brand from Lowe's. the brand name is unimportant as long as its 20° Baume.

Ok so the HCL is good to go then? All 3 bottles are 31.5% 20 deg Baume. Any thoughts on if the Aluminum would have ruined the batch even if it was for a very brief time?

 

[Geo]

aluminum would have neutralized hcl much, much faster than copper and would have cemented the copper out of your solution for a short time but in all, i doubt it had much ill effect on it. it should be just fine. do try to keep the aluminum out of you solutions unless you want to cement base metal and/or generate alot of heat.

 

[kkmonte]

I've used the HCL on the left before from Lowes, seems to work OK, I then went to a small mom and pop hardware store and got some other good name brand that doesn't have "safe" anywhere on the bottle. I told the guy I want your most dangerous HCL you have!