A step-by-step approach (AP Method)

[In Love With]

Hello all,

for the past days I have been reading and watching A LOT about the AP Method and it almost feels like the more I read, the more confused I get ...

Already the very first step is so unclear (Mixing HCl and H2O2)

I read from adding just a hint of H2O2 (1-2 caps) to 2x parts of HCl and 1x part of H2O2 to even 3x parts of HCl and 1x part of H2O2 ... Now what would be ideal for fingers?

Am pretty sure this has been asked before, but is there a step-by-step approach to this? I am by no means a chemist and am struggling to find a sound way of doing this ...

Any help greatly appreciated, thanks

ILW

 

[Shark]

You aren't trying to create AP. AP is like a nick name for copper(II)chloride, it is a process to cause a specific reaction. You want to produce copper(II)chloride. This is a basic combination of copper oxide and HCl acid. The reason for the peroxide is to cause clean copper to corrode, producing copper oxide. The green coating you see on old copper. This copper oxide mixed with hydrochloric acid will create the copper(II)chloride that causes the copper and some other metals to dissolve better than hydrochloric alone. It speeds up the creation of the CuCl2. A simple aquarium air pump and bubbling the air in HCl and a bit of copper, (or material you want to process such as memory fingers) will cause the same reaction although it may be a tiny bit slower.

 

[orvi]

AP process is catalytic. Copper can react with Cu(II) ions in solution, forming 2 Cu(I) ions. These Cu(I) are then oxidized by oxygen in air to Cu(II) and thus could dissolve more copper. You need just a small ammount of CuCl2 for the start of the reaction, then it is self-sufficient, and only need HCL and oxygen to finish the dissolution of rest of copper.
H2O2 is used to speed up the proces of CuCl2 formation - that needed Cu(II). It is not necessary at all, but it takes longer to build up the concentration needed for effective reaction.
If you are worried about Au dissolution, when added too much H2O2, you can grab a bigger bunch of some copper cable (skinned, of course), and heat it with torch to red heat, then let it cool down. Black stuff on the surface, which forms after reaction with oxygen is copper oxide. If you soak this oxidized copper in HCL, it will dissolve, forming green CuCl2 - and you obviate H2O2 usage. Use this "green" HCL to kickstart the dissolution.

When you will have some used AP solution, you can use this spent solution to kickstart the reaction.

But I say it again, you do not need H2O2 or any "starter" for the reaction at all. If you bubble air through the solution, you will get the reaction anyway, but it will probably take one or two more days.

 

[In Love With]

Shark and Orvi,

THANK YOU ...


That makes sense, so might just go ahead with a splash of H2O2 (as I bought 10 liters anyway) and a small sample of neatly cut fingers to get me going.

Might use this thread to share/ask along the way as I need to get things right prior to using much bigger amounts

 

[orvi]

Shark and Orvi,

THANK YOU ...


That makes sense, so might just go ahead with a splash of H2O2 (as I bought 10 liters anyway) and a small sample of neatly cut fingers to get me going.

Might use this thread to share/ask along the way as I need to get things right prior to using much bigger amounts

That is a good strategy, and I appreciate your cautious approach. We usually deal with opposite side of the coin here
AP is very simple and practically, it cannot be done wrong, if you do not mix any other chemical with HCL. At room temperature, oxygen has not enough oxidizing power to dissolve gold, so you are safe with this.
Simply said, you just dump your fingers in HCL, stick the tubing from aquarium pump inside, set the bucket somewhere outside, where fumes of HCL won´t be an issue and abandon it for a week or so.
Then you open the lid that way you don´t get a whiff of HCL vapor and examine the fingers. I advise you to get PLASTIC "tweezers" for BBQ (for turning the meat on the grill) to elegantly fish out the fingers and watch if they are done (foils flaking off), or they need more time.
You also check the colour of the solution - if it is green, deep green, OK. If it is black and grey-white sediment start to develop on the bottom, it is time to change the juice for fresh HCL (saturation point - white ppt is CuCl).
If the batch is done (foils flaked off the boards), just simply fish out the boards using coarse mesh sieve (PLASTIC), examine for foils, eventually wash the foils down, and pass bulk solution through fine strainer to catch them.
If you were stirring the solution too much, you will likely break majority of foils to the smaller pieces, and then, filtration through Buchner may be better option then kitchen strainer

And you are half way to your gold button wear goggles and PPE and have some bucket of water near you - if some accident happen, you can quickly wash yourself.

 

[In Love With]

Hello all,

Quite excited ... Just started my first 2x batches. I am aware that I do not have a "bubbler" but as far as I understood it, as long as it gets stirred every now and again, all "platings" will come off after a while (Aim is to let it soak for 4 weeks or so)

So then, been reading further and there are quite a few more questions popping up

How do I "reuse" the CuCl2 solution. As far as I understood as long as the solution is "greenish" its good to go again. What do I do once it changes colour though?

and is this process good for gold plated brass and/or copper contacts as well (can provide photos of the materials in question)?

Thanks once again
ILW

 

[Shark]

CuCl2 works best when there is an excess of it. This allows for it to absorb and hold oxygen which keeps it working at it's peak potential. Starting with a small volume is not a bad thing though. I started in a 1500ml beaker and shortly went to keeping three gallons going all the time. If you plan on leaving it for 4 weeks, I would probably add a small cap full of peroxide, stir gently, and leave it sitting. An air pump in a small container is messy, as the bubbles will send it flying all over the place. Or add the pump and sit it in a five gallon bucket with the lid on it loosely to contain the splatter (or plastic wrap lid). To reuse it, I allowed it to sit with the top open and bubbled very fine bubbles through it with no to very little materials in it. I processed my larger volume in a five gallon bucket sitting an 50 gallon drum to contain the splatter, sometimes with a plastic wrap (from the kitchen) cover to funnel the solution back into the smaller bucket.

Starting a new batch you just start with fresh HCl, and add a bit of your old solution and it will kick start a fresh solution.

A down side to this is that once it becomes heavy laden with copper, it will start to drop out white needle like crystals of CuCl(I). And even extra oxygen can't keep it in solution. At this point I usually sent it to my stock pot and started a fresh batch. Orvi or some of the others with better chemistry understanding might be able to explain how to get excess copper out by plating it out. I am a bit uncomfortable trying to explain it myself as the way I do it is a bit unorthodox and crude.

To add to it, this is after it starts becoming dark and/or stops working.

 

[Shark]

See Dave's post here. It will help.

https://goldrefiningforum.com/threads/non-chemical-approach.31501/post-332381