Refining Computer Scrap Problem

[mcmurraysm]

I'm new to this forum and in need of help with my current gold refining project. I found this forum whilst searching for answers after my endeavor with refining computer scrap did not go as planned. I have read through previous posts and been very excited at the information and knowledge that is possessed by other members. I have also read through Hoke's book as it has been referenced many times. I have however not been able to find a suitable solution to my situation.

I gained my preliminary knowledge from an ebay CD and slowly acquired computer parts out of the trash on my walk to and from work. My first batch, which I'm currently on, consists of various processors, fingers, pins, and a few small pieces of gold and gold filled jewelry. I was under the impression that if i dissolved all of the metal contained in these parts, I could then precipitate out only the gold. This did not turn out to be the case.

I mixed up a batch of aqua regia (muriatic acid, water, and sodium nitrate) and let the acid work on the 5 gallon bucket of parts. The following morning, all of the metal had been dissolved. I filtered out the fiberglass and plastic remnants, rinsed them and was left with a nearly full 5 gallon bucket of deep green brownish liquid. I added urea to the mix until it no longer dissolved to neutralize the nitric acid. I dissolved around 100g of SMB in water and added it to the mix in order to precipitate out the gold. I noticed a slight color change, but nothing dropped out. I waited until the following morning and checked the bottom of the bucket. To my disappointment, all that was there was a small amount of gray sludge, which i noticed had been there since the filtering of the aqua regia. Based on my reading, I assume it is silver chloride.

I know there is a considerable amount of gold dissolved in the solution, as well as copper, tin, silver, lead, and perhaps steel. How do I proceed from here to get the gold out? Any help that can be given would be greatly appreciated.

I might note that I did have success on a small batch of scrap karat gold with this same method. It however did not contain as many base metals.

 

[Harold_V]

If you've read any of my posts, you quickly come to understand that I am strictly against the recovery of precious metals by the method you chose to use.

Reason??

Because we have a never ending supply of people like you asking the same question. Where did I go wrong?

My answer to that is by attempting to recover values without dealing with the base metals first. Only under very unusual circumstances is that ever a good idea, yet the method persists, because those that don't have a clue won't let go of the idea.

I'm concerned that you have discarded some of your values. AR doesn't always dissolve karat gold unless you know what you're doing. With luck, you have not discarded anything.

Want to recover your values and start over?

Get some copper -----sheet is good, as is copper buss bar, but wire will work---it's just a lot more work, especially if it breaks down to small pieces and is not fully consumed.

Place copper in your solution and give it time. While it's there, get on with making some stannous chloride, so you can test your solution for values. Hoke talks about the testing, so refer to her book so you understand the reactions.

Values will be cemented on the copper, which will dissolved by the cementation. The values will not resemble gold, but will most likely manifest themselves as a dark deposit--leaning towards black. Leave the copper in the solution until it tests barren, then remove the copper and wash it well, collecting all of the black sludge that comes from the surface. Remember, that's your values.

When the entire lot has settled totally, siphon off the majority of solution, then wash the solids to a large vessel that is capable of being heated. Allow it to settle once again, then siphon the fluid off. Rinse with tap water and repeat, until the solution is clear of color. The solids that remain contain your values. Get that far and continue to study Hoke and you may know what to do next. If not, ask.

Do not dump the waste solution without first recovering the copper, which you can do by introducing scrap steel to the fluid. It will cement the copper.

Oh, yeah! Welcome to the forum. If you pay attention, you can learn to refine here---safely.

Harold

PS--

There may be a lot more to this than you realize. One of the possibilities is your solution is barren now--because the values were dissolved and cemented by the remaining base metals you included in the process. Key to recovery, here, is that you have NOT discarded anything.
If the white substance formed after filtration, it most likely is NOT silver. Very little silver will remain after fitration, although a trace is known to behave much like gold.

 

[butcher]

welcome mcmurraysm, you need more reading what a mess and a big batch of mistake's aqua regia works great for gold, but makes a mess if you mix gold and base metals urea and junk.

do you have stannous chloride, this is your first lesson study it.
after testing solution you can determine if it holds value. decant (remove) liquid from powder,
if test shows positive then cement out values with copper metal, depending you may need to add a little HCl and boiling with large copper bar, brush off old copper bar and rinse (save this bar for processes like this, (I store my buss bar mine in H2O).let solution settle and decant and test solution


powder's dry incenerate store in jar untill you are sure of how to treat to remove base metals and then process for values, I would go on but only after you read some more (otherwise you would only get part of how to do and will not learn how to do this in other situations).

you will have very possibly lead in these powders as well as silver and values.

this should help you get back on track, sorry for not holding your hand but after you get going you may see why I won't. good luck buddy can not wait to see that beutiful golden button, PS ask questions when you get stuck in your study.

 

[lazersteve]

Welcome to the forum,

The gray sludge is likely copper I chloride or the residue from crushed cpus if any were in the mix. Copper I Chloride is a sign of copper saturation in the solution and easily dissolves with HCl. Solutions that are saturated with copper seldom contain any dissolved gold.

Take it slow and start small until you learn what to look for.


Steve

 

[mcmurraysm]

Thank you all for your help, I am currently trying the copper buss bar method. I read about this method in chapter 6 of Hoke's book. As inquired, I have not thrown anything away throughout my process. All of the decant liquids and cloth filters are still intact. What was left in the cloth filters, i presumed was tin paste as described in chapter 7 special cases.

I have been trying to make a stannous chloride solution since the beginning of this experiment, but I'm not sure if I have done it correctly. I simply dissolved a piece of tin heavy solder in muriatic acid and poured the clear liquid into a eye dropper. None of my solutions have given me a positive dark reaction though, even the successful aqua regia solution of karat gold. Does this sound correct?

 

[Harold_V]

I have been trying to make a stannous chloride solution since the beginning of this experiment, but I'm not sure if I have done it correctly. I simply dissolved a piece of tin heavy solder in muriatic acid and poured the clear liquid into a eye dropper. None of my solutions have given me a positive dark reaction though, even the successful aqua regia solution of karat gold. Does this sound correct?

Something isn't adding up---or your solution has a huge excess of free nitric.

Make sure the solder you used is 95% tin---the balance isn't too important and will likely not dissolve. I believe Lazersteve has instructions for making the solution. Check his sig line and his web site.

When you attempt to test a solution that is highly acidic, the results are mixed. Careful observation may show a fast display which immediately dissolves---but you most likely will not get a response.

I hope you can see the reason behind my insistence on gaining knowledge before jumping in. Once you are familiar with testing procedures, it'd easy to make determinations. Right now, the big question is where is your gold, and why isn't the stannous chloride solution working? Without being there, it's a difficult chore to answer.

Read Hoke on making a standard gold solution. Follow her instructions carefully---and use the resulting solution to verify that you have a functional stannous chloride. That will familiarize you with the proper reaction, and permit you to determine if any of your solutions contain values. Clear this hurdle before you move on. You may have to make a purchase of a grain of pure gold from one of the readers---but that's no big deal---a grain is 1/480th of an ounce. That is enough to make a fluid ounce of standard solution. That, in turn, can be used to test the stannous chloride solution, which has a limited shelf life. When it no longer reacts properly, you know to make more.

Harold