Help Needed with the Hcl/Cl Dissolution Process

[Jhuff8181]

I’m working with a batch of 400 grams of gold filled jewelry and eyeglasses. I started with Nitric Acid/ distilled water, boiled until there were no more brown fumes or reaction. Poured off and filtered the liquid. Washed the remaining “gold” with distilled water three times until liquid was mostly clear. Saved all filtered powder & solids. I then added two cups of Hcl. Over the next 20 minutes I added one cup of Unscented Clorox (8.25% Sodium Hypochloride) and increased heat to medium. Liquid was medium golden green in color and the foam was yellow. After 30 minutes I noticed there was still a lot of solids in the pot so I added another ¼ cup of Clorox. Increased heat slightly and ran for about three hours. There was constant bubbling the whole time. I poured off and filtered the liquid (now dark green) and I was left with what you see in the picture. The weight is 26 grams. Here is my question, why didn’t the solids and flakes dissolve? What am I doing wrong? Did I simply not wait long enough?

John

 

[FrugalRefiner]

John,

It sounds like you didn't get all of the base metals digested in your nitric bath. I'm guessing the HCl and Clorox continued to primarily attack base metals, since it ended up dark green. If this is the case, your gold should still be in the yellow foils plus any brown/black sediment that may have formed.

Did you test your solutions with stannous chloride to see if there was any gold in any of them? Do you still have all the solutions and sediments? As long as you don't throw anything away, you won't lose your gold.

Dave

 

[Jhuff8181]

I guess I should have said a little more. This is pretty much what it looked like when I added the hcl/cl. The fine flakes were and are still fine flakes.

Yes I have the solution and yes I have tested it for gold and gold is there so nothing has been lost. If there were / are still base metals did I need to add more nitric? I used 1420 ml as per Steve's formula. If the reaction stopped was the nitric all used up?

 

[Palladium]

Hcl chlorox is meant for very thin foils. The foils from electronics are 24 karat, thin, and dissolve fast. The foils from GF are karated and thicker in comparison and are a mix of gold and some alloys. If you will look at this chart you can see the size difference in comparison. Go to ar after the nitric bath.

 

[Jhuff8181]

Hcl chlorox is meant for very thin foils. The foils from electronics are 24 karat, thin, and dissolve fast. The foils from GF are karated and thicker in comparison and are a mix of gold and some alloys. If you will look at this chart you can see the size difference in comparison. Go to ar after the nitric bath.

So your saying everything I learned from Steve's video was wrong?

 

[Palladium]

Is that the process he teaches for gold filled???

 

[Jhuff8181]

First HNO3/H2O, wash and rinse, HCL/CL then drop with SMB (simplified version).

 

[Palladium]

Wow! I don't know what to tell you then. You will have to ask him about that one.

 

[kane333]

I started with Nitric Acid/ distilled water, boiled until there were no more brown fumes or reaction.
John

How concentrated is your Nitric? Also, in the video, Steve never "boils" the HNO3/H2O mix. He turns the heat on low only, and only after the reaction has stopped completely.

 

[Jhuff8181]

Poor wording on my part, the reaction "bubbled" until the fumes stopped and the reaction ended.

 

[vegaswinner]

If I remember rightly Steve does 2 hcl/cl dissolutions in the GF video and still has solids left over which go to the next batch. Palladium is 100% correct also, after the nitric bath AR will do a much better job dissolving the remaining foils and any residual base metals. It is also worth mentioning when working with nitric to remove base metal after the reaction finishes I always add a couple of ml to ensure the reaction has exhausted due to lack of base metals rather than no free nitric, a tiny bit of free nitric here is no problem as we are not dropping gold from this solution. A tiny bit of base metal in with your foils is probably more of a problem here.

 

[lazersteve]

My gold filled video discusses using either HCl-Cl or AR after dilute nitric acid treatment. Some larger left over pieces are closer to karat than gold foils and would require inquarting and/or AR. Another thing you do not mention is how much stirring was involved. HCl-Cl requires a lot of stirring, stirring is more important than heating with HCl-Cl in my opinion.

I agree that you must have had some base metals remaining after the nitric acid treatment. Base metals must all be removed for the HCl-Cl to work properly.

Your picture of the left overs is very interesting, I have never seen left overs from a reaction so brightly golden colored as yours. My left overs are typically purple (silver chloride crusting) or red-brown (undissolved gold).

Steve

 

[Jhuff8181]

Probably did not stir enough. Well I guess it is on to AR.

Your picture of the left overs is very interesting, I have never seen left overs from a reaction so brightly golden colored as yours. My left overs are typically purple (silver chloride crusting) or red-brown (undissolved gold).

I washed what was leftover many times to be able to show what was left over in the photo. I do have a lot of red-brown powder from my filters.

 

[lazersteve]

Judging from the color of the leftovers they are most likely medium grade karat pieces and not the run of the mill GF foils.

I would recommend that you melt the leftovers with three times their weight in silver, then remove the silver with 50/50 HNO3. This will leave a nice gold sponge for you to process in AR.

Your gold filled must have been very high grade to get leftovers that look that close to karat gold.

If the foils are very thin (can't tell from your photo) then you may have success going straight to AR. If they are karat (as I suspect from the color) you will get a layer of silver chloride crust which will stop the dissolution of the gold.

It seems there has been some confusion as to the proper time to use HCl-Cl on GF scrap. To be clear, you should only be using HCl-Cl in the GF process after all of the base metals have been dissolved with diluted nitric acid. If your nitric acid quits reacting and your still have large solid pieces in the mix, you need to add a little more nitric acid. If the addition of nitric does not kick start the reaction, then you have a saturated solution and need to swap out the nitric acid with a fresh batch. Moving to filtering and AR when the solution saturates prior to removing all of the base metals saves on nitric acid in the recovery stage, but consumes more nitric acid in the AR stage and has a greater chance of forming a silver chloride crust making complete dissolution of your gold filled much harder. You'll know the nitric stage is complete when the foils are lightweight and move freely around the reaction vessel. I check my foils with a large plastic spoon by pushing on them, if they crinkle and crunch the nitric stage is complete, if they are hard you are not done with the nitric acid.

Steve