# Starting Over... Slowly



## megaplow (Apr 5, 2012)

Hey All,
I am going way slower and smaller this time and have what I believe to be my 1st success. I used nitric acid to remove the base metals from a few fingers. Now there are flakes floating in the acid. 

Does this sound right for next steps?
Filter the acid to recover the flakes
Rince the flakes
Dissolve them in AG

Joe


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## 4metals (Apr 5, 2012)

Do you mean melt them in silver Ag, or dissolve them in aqua regia (AR)? Both will work but foils are clean enough to skip the inuarting step and go right to aqua regia.


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## megaplow (Apr 5, 2012)

Thanks for the replay, I meant AR.


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## 4metals (Apr 5, 2012)

That's the right sequence, good luck this time. what went wrong the first time?


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## butcher (Apr 6, 2012)

Joe, 
Hydrochloric acid and bleach is much easier to deal with than aqua regia.


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## megaplow (Apr 6, 2012)

Butcher,
Thank you for your insight and all your help. If I knew this process was going to be so complicated, I may not have started in the 1st place. The instructions on my subzero kit were super simple and left out about 10,000 details. That said, it is getting to be a bit more fun now that I am starting to understand the bigger picture. Since I am in this far I figure I will see this thing through. At this point getting gold will be cool, but what I am more concerned with is not creating a toxic spill. I am clear on neutralizing my solutions and proper disposal. This has been an unexpected adventure. 

Today I spent some time on youtube looking at other peoples success and failures. There is some cool stuf out there. I will be sure and keep you all posted. As of now I still have the flakes in the nitric acid and wont be able to make another move till next week. 

4metals,
The 1st time I followed the directions on a Subzero kit. 1) Put everything in AR, 2) add storm precipitant, 3) collect your gold. Nothing about getting base metals out of the way, nothing about a lot of things. My original thread and journey is here: http://goldrefiningforum.com/phpBB3/viewtopic.php?t=12947

Again, I cant thank you all enough, this forum has been invaluable, 
Joe


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## nickvc (Apr 6, 2012)

Joe I think your starting to understand that refining isn't that simple unless you know what your doing, your initial failure will give you a fantastic opportunity to learn how to recover and refine your values, it's a mess and a headache but with patience and studying you will sort it.
We want new members to succeed here and are all pleased when new members get their first button but that comes with a price, reading and studying...it's that simple.


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## butcher (Apr 6, 2012)

Joe megaplow, 
nitric acid will remove copper from the memory fingers, but be careful of adding solder or tin in this solution.

The hydrochloric acid and 3% hydrogen peroxide process sometimes refered to as the AP process or copper II chloride leach, is a great method to learn, it works great for memory fingers and many other items, this low cost leach will save you from using your expensive nitric acid (best saved for other processes), Laser steves web site check out his videos, documents, and posts they will give many details of the process, the solution can be reused, and rejuvinated, until it is contaminated, it is also much safer than the nitric acid fumes.


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## maynman1751 (Apr 6, 2012)

> Today I spent some time on youtube looking at other peoples success and failures. There is some cool stuf out there.



As with the Sub-Zero kit, be careful and selective about what you see and/or believe on YouTube. :roll: Some of the videos are just plain crap and some, like the ones done by some of our very own illustrious members, are spot on and extremely instructional. Be cautious and if in doubt, ask questions *HERE*!


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## megaplow (Apr 14, 2012)

Hey All,
I have finished my 1st round of nitric acid with a small set of boards. The boards have stopped reacting with the nitric acid so I decanted the acid and have washed the flakes several times with distilled water. Now I am going to make my AR and dissolve the gold flakes. I would also like to throw my filters in as well. Is there a proper amount of AR I should make? I figure an easy way would be to fill the beaker with hcl and then slowly add nitric acid to it. That way I can be sure all the nitric acid gets used up before adding more. Sound like a god plan?







Joe


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## megaplow (Apr 14, 2012)

Butcher,
Just saw your post about the hydrogen peroxide. I would love to do this on the cheap and less toxic path. I will read up and do an experiment it that direction.
Joe


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## goldenchild (Apr 14, 2012)

Thats a nice amount of foils. 100ml of HCL should do it. I wouldn't even add nitric for foils. A tiny amount of 20% peroxide or clorox will work nicely. If you are going to use nitric add in very small amounts. I'm talking literally by the drop for those foils. Good work 8)


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## philddreamer (Apr 14, 2012)

Hi Joe!
Try this as a guide:



> ) Dissolve gold in AR solution. (80% HCI / 20% Nitric. Apply heat)
> (Hoke states, 4 fl oz HCI (muratic acid) + 1fl oz HNO3 (nitric acid) will dissolve 1 troy oz of gold. This is equivalent to 31ml of HCI + 8ml of HNO3 per gm of gold.



Take care!

Phil


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## maynman1751 (Apr 14, 2012)

Definitely go with what Butcher and goldenchild said and use HCl/Cl (hydrochloric/bleach). Cheap, easy and a little less toxic. Just my 2cents!


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## megaplow (Apr 15, 2012)

Thanks for all the help,
I added my flakes to about 8oz of HCL and 3 oz of CL. I am going to let it sit overnight and check in the morning. In the bicture below is my HCL/CL and some nitric working on a fresh batch.


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## butcher (Apr 15, 2012)

I like the pretty yellow color.

Just for fun do some experimenting with the stannous chloride test, remember you may have to let excess chlorine gas fume off before seeing the reaction.


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## nickvc (Apr 15, 2012)

Looks like we have a new member that listens and learns,the potential for a valuable member well done 8)


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## megaplow (Apr 15, 2012)

I am confused,
Tonight I made a little batch of copperas + water + hcl. I hope I bought the right stuff (blush). I was going to use this to start the precipitation process in my gold solution. I tested my solution prior to the addition of the copperas and it was purple and ultimately turned black. After adding the coperas, nothing happened and now, the solution is turning green when I test it.

The copperas I bought were: 
http://www.acehardwaresuperstore.com/1741-soil-conditioners-smlpk/109871.html

Here is a picture of my current test.





What did I do wrong? Did I ruin my solution?

Joe


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## butcher (Apr 16, 2012)

The violet test using stannous chloride, before you added copperas, tell us you had gold in solution (which we already knew), but it also told us you did not over use on the oxidizer (or the tin chloride would have not reduced the gold to the purple color), it also proved to you your stannous chloride solution is good and working.

I am assuming here you just added copperas to a small test sample, and then retried the stannous chloride test on this same test solution, and did not see a reaction with the tin (violet color reaction).

Were the copperas (ferrous sulfate crystals) green (fresh) or were they brown (oxidized)?

If you had a few drops of gold in solution in a spot plate, and added fresh copperas crystal, you would see a brown ring (gold precipitate), this is also a test for gold in solution (similar to the stannous chloride test for gold), copperas reduces gold to metal, so trying the stannous test after using copperas on this solution would not show a violet reaction, as the gold is already reduced to metal by the iron in the copperas (ferrous sulfate crystal).

The green can come from iron (in the iron sulfate crystal) (copperas) and the chloride solutions, iron replaces the gold in solution.

If the copperas crystals are brown I would not try and precipitate gold with them, the copperas oxidizes in air and will not work well to precipitate gold.

You can make your own copperas fairly easily, and have a supply of beautiful green crystals to work with, I can explain how I make mine out of transformer laminates and dilute sulfuric acid, or a search you should also be able to find it.

I do not know for sure I understood your question or if you can understand how I explained this if not maybe someone can word it better.


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## megaplow (Apr 16, 2012)

Butcher,
Thanks again for the insightful response. My copperas are a pale green, they look like these:
http://i01.i.aliimg.com/img/pb/028/588/438/438588028_933.jpg

Based on Hoke's formula and me hoping I had a .25oz of gold in my solution. I mixed up .25 of a lb of copperas with .25 of a litre of water. My current batch is a sample batch, so I added that amount to my whole batch. I wish I had pulled some aside to test. I never saw a brown cloud form and nothing has precipitated. The solution is still a deep gold color and clear. 

As I understand this reaction, the iron is going to replace the au in my solution. That way the au can fall out. I know other reactions require the solution to be saturated with some materials in order to push others out. 

I guess my questions are:
Why didn't anything precipitate from my solution?
Did I mess up this batch too? 
Will heating it up help? All my work has been done at room temperature.

Joe


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## Palladium (Apr 16, 2012)

Hoke says 1lb (453.59 g) per 50 penny weight of gold.
50 penny= 2.74 oz
2.74 oz = 86.31 g
453.59/86.31= 5.25 g copperas per gram of gold.

You had 1/4 oz of gold= 7.875 g
7.875 X 5.25= 41.3 g copperas needed

Did you add the whole copperas you mixed (113.4 g ) to your solution? That's almost 3 times what you need.


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## megaplow (Apr 16, 2012)

Thanks for catching that. I forgot, I didn't add the full amount.
I only added about 1/3rd. As I was pouring and never saw a cloud form I assumed I was doing something wrong. Thats when I pulled a little aside and did a test.My test even with too much copperas never formed a cloud. 

Joe


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## megaplow (Apr 16, 2012)

One more problem with my current solution. I believe I should have used 100ml of HCL. I wound up using 8oz. Since I used too much HCL and CL will I see issues from that?

Joe


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## Palladium (Apr 16, 2012)

You can over shoot the hcl and it shouldn't cause problems. It's the oxidizers that cause problems with your solutions (nitric, cl, H2O2 ). These will also cause problems with you reading your stannous test for gold in solution. Cl and H2O2 is faily easy to break down with heat where as nitric is not. You may still have some free cl in your solution is why it won't drop. When this happens to me i cover the beaker with a watch glass so nothing can escape but the gas and i put it on a slow boil for about an hour to remove the free Cl. This is different from evaporation where you don't boil. Then i sit it to the side for about an hour or two to cool and then try your drop again.


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## megaplow (Apr 16, 2012)

Previously when I was using HCL + Nitric acid, I used the non boil method to get rid of the nitric acid. This time I will boil the solution in order to remove the cl. Is there any way I can tell how long to boil it or when the cl is gone? I am relieved that there is still hope for this batch.


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## Palladium (Apr 16, 2012)

I didn't say their was hope. Well i guess their is always hope. lol
If nothing else you can use a piece of copper wire and make a recovery effort so all is not lost. Cl and H2O2 beak down with heat pretty fast when the temp of the solution rises. The hotter the solution the less it will hold when it comes to a gas. Different gas will have different percentages of gas it will hold per volume of solution. Cl will gas off pretty quick when the temperature rises so about an hour should do the volume you have, probably less but i say an hour for good measure. When i said boil earlier i meat just the point where you see bubbles starting to form and hold it right about there. Not a roaring boil!


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## butcher (Apr 17, 2012)

megaplow, 
I believe your still on track, and Palladium, is giving good advice keep following his advice, I just thought I may add something to consider, your solution looked good in the picture above, this sounds like a minor problem, that you can overcome easily, I would give it a good heating, cover and let it sit overnight, check it next day to see if you have a brown powder in the bottom, take a sample of solution and test with stannous chloride, also take a sample in a white spoon or spot plate add a few crystals of the ferrous sulfate (copperas), if violet in stannous chloride test, or brown precipitate in spot plate you will know what to do next.

Those copperas crystals in the link you posted look good, keep them from air.


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## megaplow (Apr 17, 2012)

Hold the press! I think I got it!

A little background. Previously I mentioned that I added copperas and nothing happened. I measured out .2oz instead of 2oz of copperas. Regardless of what I added, the cl left in the solution was causing problems. Once I added the copperas, the solution was no longer testing positive for gold. After a good simmer, the solution once again tested positive. This is also the 1st time I have heated any of my solutions. I was trying to avoid it, but its a necessary process. 

Last night I made up a new batch of copperas and added it to my solution. You can see the video here.
http://youtu.be/LkLRpigA5EI

Today I woke up to find this:






Tonight I will test the solution to see if there is still more gold in it. Then add enough copperas to drop that. Then hopefully be rinsing and making a tiny tiny button. 

Thank you all for your help, you guys are amazing! 
One thing I would like to change next time would be to use H2O2 instead of CL. I feel its less toxic. I am ready to process the rest of my boards using my current technique. Nitric acid to remove base metals, then HCL and H2O2 to dissolve the gold, then copperas to get it back. 

I really wish I knew all this before my 1st batch,
Joe


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## Palladium (Apr 17, 2012)

Glad you got it joe!
Now if you can help me figure out this Adobe thing out we will both be happy. :twisted: 

[youtube]http://www.youtube.com/watch?v=zu2XA7u4WTg&feature=relmfu[/youtube]


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## megaplow (Apr 17, 2012)

Oh man... (facepalm)


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## Palladium (Apr 17, 2012)

megaplow said:


> Oh man... (facepalm)



I think your pretty cool Joe. Keep up the good work.


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## goldenchild (Apr 17, 2012)

megaplow said:


> Oh man... (facepalm)



So you're the one making the endless stream of updates! :lol: Joe, do you do any work on dreamweaver? That's our primary ide at my job using ColdFusion. Nice to see another tinkerer on the forum. Admittedly a much more sophisticated tinkerer.


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## megaplow (Apr 18, 2012)

Two steps forward and...
Since I was seeing some success, I started another small batch. The boards were mostly stripped and there was a good collection of flakes on the bottom. There was still a lot of gold left on several of the boards. I figured I would try heating the solution in an effort to make the acid more agressive. The previously attached gold was free, but now all my flakes have disappeared. I was under the impression that nitric acid alone couldn't dissolve gold. I am assuming my solution is now base metals and gold. 

Joe


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## butcher (Apr 18, 2012)

It may just show up as brown powder, (you may have had some chloride contamination somewhere like water, dirty vessels?), just keep adding copper to the solution until no more copper reacts even with heat, any gold would be pushed out of solution.

If you have any tin you will also form gold colloids, circuit boards have solder, the tin and gold my be in the filter later as gold colloids and tin gelatin, incineration of the filters and a boiling wash in HCl, and hot water rinses, you can get the gold back, a big pain in the back side, keeping tin out of nitric to begin with is really the key.

I would choose acid peroxide to remove copper and foils from the boards, (removing as much solder before hand with HCl), the copper II chloride leach is much cheaper than nitric for me, and although a challenge (tin still big trouble),it seems somewhat easier to deal with in concentrated HCl solutions.

Tin as far as I am concerned is a collector of fine gold (forming colloids), so anytime I have tin and dissolved gold or gold powders, the filtered material is reprocessed for values.

Keeping tin out of solution should be the goal; it just makes things so much simpler.


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## megaplow (Apr 19, 2012)

Very insightful,
The boards I am using are clean and have no components on them. Thus no solder. My through holes and all mounting points are gold. After some time in heated acid, the green portion of the board separated exposing the fiberglass and whole underside. I assume this is where the tin may have entered the mix. There is an orangish gell on everything now. I guess thats my tin colloid. I will push out the tin with copper and see how that goes. For my next small batch I will be using hcl /peroxide to dissolve my gold. What is the nitric acid substitute for getting rid of base metals?

Take care,
Joe


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## Harold_V (Apr 19, 2012)

megaplow said:


> Previously when I was using HCL + Nitric acid, I used the non boil method to get rid of the nitric acid. This time I will boil the solution in order to remove the cl. Is there any way I can tell how long to boil it or when the cl is gone? I am relieved that there is still hope for this batch.


I would caution you against boiling so long as you have gold in solution. There's no real benefit in doing so, in that heating to near boiling will rapidly expel chlorine without risk of losing any values. In any case, make sure you have a watch glass covering the vessel, to prevent contamination, as well as to capture any traces of values that may be expelled by over heating (boiling). 

Harold


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## butcher (Apr 19, 2012)

"I will push out the tin with copper and see how that goes."

Copper would not cement tin; tin is higher in the reactivity series of metals than copper.
Filtering may capture most of the tin (it forms a gelatinous substance that clogs filter pores), but if much tin that may prove difficult, (Charmin-plug or fiberglass plugged funnel can help some), if tin content is high, if tin content is extremely high the only solution at times is to completely evaporate solution, dry powders and incinerate, and wash tin oxide in boiling HCl, (that does not sound like the case here).

"For my next small batch I will be using HCl /peroxide to dissolve my gold."

HCl with small addition of 3% H2O2 peroxide will dissolve copper not gold;
This copper II chloride leach is reusable.
HCl and strong peroxide would dissolve gold, but this should only be used after base metals are removed, and here I would use the HCl and bleach method normally, if dissolving gold was my intent.

"What is the nitric acid substitute for getting rid of base metals?"

Copper II chloride leach also called Acid peroxide, or (AP leach), if I understand the question I think you are asking.


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## megaplow (Apr 19, 2012)

In my 1st batch I wound up with a solution containing all metals, base and valuable. That batch is still in the corner waiting for my return. I dont feel ready for a relationship with her yet, so she is going to have to wait. In the mean time I have had some success with smaller batches and different acids. Things were going swimmingly until I added heat to nitric acid and wound up with an overly dissolved solution again. 

Moving forward I am looking for a solution that will dissolve base metals without dissolving gold. Sounds like AP leach is going to be my new tool for doing that. I like that it is reusable too. What scares me is that if I get the mix wrong I will dissolve the gold too. The nitric acid doesn't make me all that comfortable, so any substitute for that is welcome. It was the 1st time I had to pay a hazardous shipping fee. 

My last success with dissolving gold (post base metal removal) was with HCL and bleach. The fumes were super strong (I was wearing a respirator, but the back yard - from the vent - smelled) so I was thinking AP leach would be better. After all the advise, I think AP leach for base metals and HCL and bleach will be the combo moving forward. 

Now for my current mess. I have taken the copper sheets out. I have about 800ml of solution that is still pretty active. I can fiter it at this point and put that aside for later incineration. Do you think I should keep dropping boards into it at room temperature until it stops reacting? Then go ahead with evaporating it and then incinerating it? I feel that evaporating and incinerating would be a waste of a lot of acid. 

Thanks again


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## butcher (Apr 19, 2012)

AP will not dissolve gold if you do not add too strong of peroxide, before working with it study it,

Just keep adding material to your leach you have now, just try and keep tin content to minimum if at all possible, a low heat will not hurt anything.no need to evaporate or incenerate at this point, after all of the nitric has reacted, you will need to filter, a large funnel and a ball of fiberglass may come in handy if there is tin on these boards.

Are you using city water with your nitric acid? Where these same boards treated with some type of HCl prior to this nitric leach, I am trying to figure out where you have chlorides and gold going into solution.

About 4.3 ml of 70% nitric acid and 4.3 ml water will dissolve a gram of copper,
Or 
About 8.6 ml of this solution per gram of copper
At about 800 ml you have almost 100 times this amount of solution, I am not sure how much copper you have on those boards, but that is a lot of solution, 800ml/8.6ml = about 93grams of copper will dissolve.

megaplow, I thought you were going to do small experiments, with your studying, getting acquainted with processes before going large scale, small experiments you do not have big mistakes to deal with while you learn.

Also I would deal with the mistake I made before starting more projects to deal with.
Did you add a copper buss bar to the first solution tyou were working on?


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## megaplow (Apr 20, 2012)

Current batch an Cl:
Looks like another oversight. I have been using 70% nitric acid with no water. All the water in my lab (I like the sound of that) has been distilled arrowhead. I don't see how any hcl could have contaminated my nitric solution. I assume the contamination is from the board itself when the green film lifted off exposing the glue or whatever was holding it on. Everything was fine till that happened. I have taken out the boards and set them aside, they were coated with slime. Is that slime tin or is it tin+gold? 

Moving forward:
I fully plan on fixing this mistake before starting anything else. The reason I am using so much solution, is because I want it to completely cover my boards. My remaining boards have been broken into smaller pieces so I wont be using so much liquid. This is also the same solution I have been using for all my "going slow tests" it was not "fresh" when I started this batch.

Now:
Last night I put in a few more boards. This morning nothing was happening. It seems the copper from a few days ago plus these new boards may have exhausted the solution. I figure all the gold on my boards has a copper under layer. I am not sure where to go from here. If my solution is done reacting should I add a little water, filter it or dry it out and incinerate it? Is there a risk to filtering too early? 

I just found this which is awesome:





Joe


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## maynman1751 (Apr 20, 2012)

> Looks like another oversight. I have been using 70% nitric acid with no water. All the water in my lab (I like the sound of that) has been distilled arrowhead. I don't see how any hcl could have contaminated my nitric solution. I assume the contamination is from the board itself when the green film lifted off exposing the glue or whatever was holding it on. Everything was fine till that happened. I have taken out the boards and set them aside, they were coated with slime. Is that slime tin or is it tin+gold?


Joe! You need to do some more reading and studying. You are making way too many mistakes and compounding your problems.
I, myself, am fairly new to this , but through reading and researching the forum, I will tell you what I see (my opinion).
1. I would not do entire boards.
2. I would not use Nitric to remove base metals when HCl/Peroxide will work just fine (but slower) and is much cheaper.
3. If you are going to use Nitric it should be diluted 50/50.
4. The full strength Nitric may be the reason that the green film (solder mask) has come loose and exposed large amounts of copper trace that is being dissolved unnecessarily in the reaction therefore exhausting your acid needlessly.

These are just a few things that I thought that I would point out. I believe most of them have already been covered by other members already. If I am wrong on any of these points I'm sure that I will be corrected. Continue to let Butcher guide you through this stage and then, if it where me, go with the AP, HCl/Cl processes until you get better acquainted with what you are doing. I am by no means an authority on this. Just trying to give some friendly advice.
Read the forum daily. The mistakes that you are making are discussed here on a daily basis. Learn from the others mistakes to avoid making the same ones yourself. Don't be discouraged. Just work smarter!


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## butcher (Apr 21, 2012)

The nitric should have been diluted, by using concentrated acid more nitric is used to make the brown NOx gas, this nitric wasted as gas, could have been used to form more nitric acid in solution and thus dissolve more metals.

Concentrated acids can act differently from dilute acid.

If you cannot dissolve any more copper with the solution, I would put the solution in a casserole dish on an electric hot plate (solid cast iron burner top or add sheet of metal between dish and the coil type burner, I would also add some water to dilute solution some, add more copper while using heat, seeing if more copper dissolves into solution, nitric acid has a way of slowing down in reaction, and you can still have much free nitric in solution. It may or may not dissolve quite a bit more copper.

If gold dissolved into solution, (and there was for some reason chloride in the nitric solution) this gold will at some point cement out onto the copper, or be pushed out of solution by the copper.

When adding whole circuit boards in a solution that dissolves gold you can have copper the gold can cement onto in places that may be very hard to get to this copper to dissolve (like under solder mask, or copper in the center layers if the circuit board on some types of circuit boards), some types of circuit boards have traces of copper sandwiched inside under and in-between the layers of fiberglass, if the gold solution comes into contact with this copper the gold could cement there, acid can also have a hard time getting to this copper to dissolve it of free this gold., Also bubbles of gas escaping from where the acid might gain access to this sandwiched copper may keep new acid from entering and dissolving the copper or freeing the gold from this copper.

Tin from solder and its problems as we have already discussed,

I would make sure the nitric will not dissolve any more copper after adding water and heat, basically to will have to saturate the solution with copper, use up the free nitric acid.

You can also take a small sample of the hot solution, in a spot plate or white spoon, add a prill of urea, watch for fizzing, if so you have free nitric acid, then test this same solution with stannous chloride for gold.


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## megaplow (May 3, 2012)

Okay,
After researching and some experimenting, things are looking up. I added some distilled water, heat and a thicker piece of copper to my solution. As the solution heated yellow smoke came off it, I assume this was the nitric acid working on the copper. Some time after the yellow smoke stopped I let the solution cool. The next day my solution had a dark layer of mud on the bottom topped with a lighter one. I added one ball of urea to the solution and it didn't react. I added a pinch of SMB and that too had no reaction. At this point I am comfortable that there is no nitric acid left in my solution. 

I decanted the fluid leaving wet mud and the clear solution. The decanted solution does not test positive for gold. Adding SMB to the solution precipitates white powder. 

I took a portion of the mud and added HCL to it. The light mud dissolved leaving black powder. 

Are these the right next steps?
1) Add HCL to all my mud.
2) Use HCL + Peroxide to dissolve it.
3) Precipitate the gold with capperas

Joe


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## maynman1751 (May 3, 2012)

> I took a portion of the mud and added HCL to it. The light mud dissolved leaving black powder.
> 
> Are these the right next steps?
> 1) Add HCL to all my mud.
> ...



When you added HCl to the mud and the light mud dissolved, what color did it make the solution?
Depending on your answer to that, yes you could 'wash' the mud in HCl to rid it of unwanted materials. I would do this in a heated solution and decant while hot to remove tin in solution. Somewhere in here you should also incinerate your powder and rinse in HCl again. Then rinse powder in water until clear. 
To dissolve use HCl/Cl not peroxide. Add a few drops of sulfuric to remove lead and filter.
You can precipitate with copperas or SMB *after ridding the solution of Cl*.

You may want to wait for a more definitive answer, but that is how I would proceed.


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## nickvc (May 3, 2012)

A few points.
1. you are using stannous to test your solutions and not just relying on the fact no gold precipitated out of your solution ?
2. By not incinerating between using nitric and hydrochloric acids you could well have made a weak AR which could redissolve your gold.
3 I really think you should just cement any values on copper, seal up your containers and do some studying, by keep experimenting without knowing what your doing your wasting chemicals, time and effort.


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## butcher (May 3, 2012)

Joe,
I agree with Nickvc, you are putting yourself right back into trouble, the troublesome metals and inorganic materials need an incineration to oxidize the tin and other base metals, and also to rid the nitrate salts from the metal salts, before a good boil in HCl, then slight dilution before decanting solution hot to remove tin and other base metals, hot water rinses at this point will also help to remove the lead chloride (insoluble in cold water but soluble in hot water.
And if you were going to do a nitric leach after this and did not want to dissolve the gold powders you would incinerate again to rid the metals of chloride salts.

Since you missed this step you still could have the trouble from tin in solution, and since you did not incinerate it is possible to have dissolved some gold, you can test for dissolved gold with stannous chloride.

Here is the double edged sword, if you do have gold in solution, and tin in solution, in this chloride solution you have made stannous chloride that reduces the gold to colloids, this gold you cannot test for in solution with your spot test of stannous chloride testing, it will not precipitate as it forms colloids that will not settle out, they repel each other keeping each other in solution, the tin in solution is also very hard to filter, and if you do you could possibly see the violet color from the purple of cassius reaction in your filter.


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## megaplow (May 3, 2012)

Thanks for all the responses,
This morning I realized I forgot to add incineration to my possible next steps. All my tests thus far have been done with stannous. I will do a small incineration test and report back. 

Joe


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## maynman1751 (May 3, 2012)

Well I almost got it right! Parts of it anyway. That's why I said to wait for a better answer. :|


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## megaplow (May 8, 2012)

Hey All,
After reading Butchers instructions on incineration I needed to schedule some time before moving forward. Last night I completed my first reduction, rince, re reduction and incineration. The powder is still giving off smoke so I need to keep them on a little more heat. I havent added hcl yet. Just an update. 

Joe


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## butcher (May 8, 2012)

During the incineration the powers will smoke as long as there are organic materials or acidic salts, if the metals are high in acidic base metals sometimes the powder will dry when heated, then fuse into a syrup type material at higher temperatures, more heat they will dry again before you can get them red hot, keep crushing the material when dry (i will try to crush just before completely dry so it is not so hard, you want to have it in fine powder to get the metals exposed to heat and air, make the powders glow red with heat, and hold this heat for a while, stir often to expose to air.

Do not breath the acidic and metallic fumes.


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## CASACEO (May 22, 2012)

megaplow said:


> Okay,
> After researching and some experimenting, things are looking up. I added some distilled water, heat and a thicker piece of copper to my solution. As the solution heated yellow smoke came off it, I assume this was the nitric acid working on the copper. Some time after the yellow smoke stopped I let the solution cool. The next day my solution had a dark layer of mud on the bottom topped with a lighter one. I added one ball of urea to the solution and it didn't react. I added a pinch of SMB and that too had no reaction. At this point I am comfortable that there is no nitric acid left in my solution.
> 
> I decanted the fluid leaving wet mud and the clear solution. The decanted solution does not test positive for gold. Adding SMB to the solution precipitates white powder.
> ...



Hi Joe, I too am new to the refining processes. From what I understand of your process, and I had to read it a couple times to make sure, you have already neutralized the nitric in your solution. SMB is naturally a white precipitate. The thicker piece of copper you added to spend the remaining nitric precipitated your gold for you. At this point in your process you could clean your gold first with water (tap or distilled is up to you) then with hcl (edited by CASACEO). After you are satisfied with your washes is when you would decide if you want to re-refine or test a small amount of gold or burn it into a button. 
If it were me I would dry it, weigh it and re-refine it.

As for your first batch, you do not have Pd in or on your boards. Pd is found in the brownish capacitors that your boards do not have. It looks to me like the boards were never populated, so that is good news. All they are is Cu Au and plastics. I would recommend separating solids from fluids, rinsing the solids off into the fluids. You will need to further dissolve your base metal, Cu, off the boards to recover the Au. AP (c II c) should do the trick now that you know a little more about it. Test the fluids for gold with SC. The copper should have cemented any values out of the solution but testing is never a bad thing. 

To reiterate, I am a newbie myself and I have very little experience. To me it sounds like you are learning the craft well and beat yourself up too much. You are doing much better then I did the first and second go at it. The first time I dumped out my solution and the second time I ended up with 1/2oz of 12k. The third time I prematurely cemented my waste with steel and I have been having a horrendous time trying to recover my PMs from that... I expect you will succeed, if not now then eventually.


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## Harold_V (May 23, 2012)

CASACEO said:


> At this point in your process you could clean your gold first with water (tap or distilled is up to you) then with hcl and a small (like a couple drops per wash) amount of 3%H2O2


I question the logic in using H2O2 at all. Not much different from using a drop of nitric, is it?

Your objective should be to wash the gold without risk of dissolving any. 

Harold


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## CASACEO (May 23, 2012)

Harold_V said:


> CASACEO said:
> 
> 
> > At this point in your process you could clean your gold first with water (tap or distilled is up to you) then with hcl and a small (like a couple drops per wash) amount of 3%H2O2
> ...



You are right Harold, in some respects. They both are oxidizing reagents and they contain some of the same elements for construction. But I disagree about the difference between the two being not much. The chemical composition of each varies enough that it's like comparing apples to oranges, yes they are both fruit but have distinct differences that cannot be ignored. HNO3 vs H2O2 the key difference the N. Aqua Regia is not made with HCL and H2O2, it needs the N. I'm not going to waste time or materials making a 3% nitric to make an equally balanced scientific comparison.

There is a possibility for gold to dissolve, but thinking you're going to be able to get every nanogram of gold in the first try off computer electronics is a little out of logic to me. Copper precipitates gold when the solution is saturated and just about all the metals in a board are copper with gold plate. This is why we keep a stock pot of waste solutions for refining later, isn't it? The reason we rejuvenate a AP (cIIc) solution? 

But using H2O2 in addition to HCL is most likely just a waste of peroxide and ultimately money (a couple drops a few thousand times will add up to a significant amount of money). Additionally allowing the few molecules of peroxide to work their magic is not going to prove efficient time management (unless you like watching reactions for hours upon hours instead of tv). I hope I explained my logic without offending you. Ultimately, I see why you didn't understand my logic... Few people do. :shock:


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## Geo (May 24, 2012)

the gold will not precipitate out on base metal if theres no base metal left. when you use AR like that, you have to proceed with the digestion until all the base metal is consumed. then it really doesnt matter how contaminated the solution is, it will hold the gold until a precipitant is used to to drop it out.

hcl/H2O2 will act in the same way, just not as aggressively. the "trick" to all this is to keep the gold in a recognizable form one way or another so that you dont misplace it. if you know your going to dissolve gold, then dissolve it all to be sure you got it all. if your not dissolving gold in a process, dont dissolve any of it for the same reason. when your not expecting to dissolve gold and you do anyway, you may reclaim it in the stock pot but why tie up values when you dont have to.


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## Harold_V (May 24, 2012)

In regards to washing gold, when base metals have been eliminated, for all practical purposes, the addition of ANYTHING that will oxidize some gold isn't a great idea. It serves no real purpose, as the second refining will provide the needed purification without risk of dissolving values when that isn't the objective. 

I may have misinterpreted your comment, thinking that you were discussing the washing of precipitated gold. In that case, assuming that's what you meant, I strongly advise that you NOT post advice to add an oxidizer---as it serves no purpose aside from creating problems. 

I took note that you are new to the forum, and new to refining. It is preferred, by far, that people such as you NOT DISPENSE advice. You should have enough wisdom to read the forum and understand what is acceptable here, so you don't create problems. Others who may not understand your lack of experience may assume that your recommendations are acceptable. That, then, has the potential to create a new wave of readers that have foolishly followed less than acceptable advice (it's called misinformation on this forum--and is strictly prohibited), creating yet more problems that must be resolved, and small fires to stamp out. None of us have time for that foolishness. 

Harold


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## CASACEO (May 25, 2012)

Harold_V said:


> In regards to washing gold, when base metals have been eliminated, for all practical purposes, the addition of ANYTHING that will oxidize some gold isn't a great idea. It serves no real purpose, as the second refining will provide the needed purification without risk of dissolving values when that isn't the objective.
> 
> I may have misinterpreted your comment, thinking that you were discussing the washing of precipitated gold. In that case, assuming that's what you meant, I strongly advise that you NOT post advice to add an oxidizer---as it serves no purpose aside from creating problems.
> 
> ...



Thanks for restating points I covered in my posting. It is clearly apparent that you misinterpreted my comments as a whole, or didn't read ALL of them (possibly both). Yes I know I misspoke and that was addressed three times in total after the fact. Others who 'may' not understand my lack of experience wouldn't have read my postings at all, it was clearly stated at the beginning and end of my first posting in this discussion. I would like to apologize for any confusion I have created and would like to thank you and 'geo' for clearing up the confusion that members 'may' have.

To Joe: If you followed all that your 3 steps are incorrect. If you are washing do not dissolve (no oxides of any type), if you are dissolving don't waste your time and chemicals washing.


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