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thehorseline

Member
Joined
Jun 2, 2011
Messages
11
Happy 4th of July to All.
My problem stems from processing the ceramic cpu's. I did the process of Aqua Regia, testing, filtering twice, nutralizing, and the metabisulfite. The Gold does not drop from solution!! It is still in solution and when tested with the stanuos chloride its very very strong. All I get is a gray very fine mud on the bottom that rises the minute you disturb the liquid. Also the solution instead of being that beautiful emerald goldish green is BLUE!! What do I do?? Any help would be appreciated immensely.
Thank You
Robert
 
Blue indicates copper in solution.

IMO, CPUs should not be processed directly with AR.

What is the color you get with your Stannous Chloride sln ? Also, is your solution fresh ?

Was it Ceramic CPUs or low grade stuff ?
 
Hello and thank you for taking the time to deal with a novice like myself. Unfortunately I processed them in AR. When I put Stannous Chloride on the Qtip that was dipped in the sln, it turns Black. Yes it is fresh I just did it yesterday. They were ceramic cpu's and maybe 20 fingers.
Thanks
 
What did you use to neutralize the AR? Did you make the AR from hydrochloric (muriatic) and nitric or did you make it from sodium nitrate and muriatic? Approx. what volume of AR was used and approx. how much metal was dissolved. In other words, give more detail.
 
Is it possible you've used a great deal more acid than was required to do the job? You may have an overwhelming amount of free nitric acid present.

You might wish to do a simple test with a piece of copper wire to see if the values will cement. I'd recommend you take a dip sample instead of insert the wire directly in the entire volume of material.

I'm guessing here---but I expect that if you have free nitric, you will likely see considerable activity at the wire, maybe even some brown fumes.

What you find may determine your next course of action in recovering the values.

In the future, you'd be well served to avoid using AR until you have eliminated the majority of base metals.

Harold
 
Harold_V said:
Is it possible you've used a great deal more acid than was required to do the job? You may have an overwhelming amount of free nitric acid present.

You might wish to do a simple test with a piece of copper wire to see if the values will cement. I'd recommend you take a dip sample instead of insert the wire directly in the entire volume of material.

I'm guessing here---but I expect that if you have free nitric, you will likely see considerable activity at the wire, maybe even some brown fumes.

What you find may determine your next course of action in recovering the values.

In the future, you'd be well served to avoid using AR until you have eliminated the majority of base metals.

Harold
Click to expand...

Those were my thoughts exactly when I made my last post. He may not know that no gold will precipitate until all of the excess free nitric has been consumed with SMB. With a lot of free nitric, it will really take a lot of SMB to kill it, although that's certainly not the best way to do it.
 
Thank you All for your time and consideration. Truely a grand group of people here.
I have some copper wire and I shall to as advised. I will post shortly for further comments. I separated some of the solution and put in a little wad of tin foil. My goodness did it go to work on the foil,,, bubbling and fizzing. Let me go and do as advised and be back with the findings asap.
Thank You all
Robert
 
thehorseline said:
Thank you All for your time and consideration. Truely a grand group of people here.
I have some copper wire and I shall to as advised. I will post shortly for further comments. I separated some of the solution and put in a little wad of tin foil. My goodness did it go to work on the foil,,, bubbling and fizzing. Let me go and do as advised and be back with the findings asap.
Thank You all
Robert
Click to expand...

By "tin foil", I assume you mean aluminum foil. That doesn't prove much since the aluminum is reacting with the muriatic, of which you will normally have a excess, whether or not any nitric is present. Free nitric is the problem.
 
Yes Im sorry I mean aluminum foil. I added 12 inches of copper that I stripped from a wire spool. So far all it does is react by tarnishing the bright shiny wire I put in. If there is a reaction,,, I dont see very much of one. I separated about 500 ml from the bright blue solution and thats the one I added the aluminum foil to. It is now a olive green clearer liquid. When I test it with the stannous choloride the Qtip turns a brown color but slowly. on the other hand the blue solution,,, it turns black instantly,,, very very black
Thanks
Robert
 
thehorseline said:
Yes Im sorry I mean aluminum foil. I added 12 inches of copper that I stripped from a wire spool. So far all it does is react by tarnishing the bright shiny wire I put in. If there is a reaction,,, I dont see very much of one. I separated about 500 ml from the bright blue solution and thats the one I added the aluminum foil to. It is now a olive green clearer liquid. When I test it with the stannous choloride the Qtip turns a brown color but slowly. on the other hand the blue solution,,, it turns black instantly,,, very very black
Thanks
Robert
Click to expand...

500ml? That is half a liter - way too much for testing. Next time do test with 10-20ml that is way more than enough.
 
I'm very confused by the blue solution. Normally, copper with traces of values will show green---a matter of how green.

Not arguing the point--if your stannous test indicates gold, it's there, regardless of the color.

Using aluminum works, but it tends to yield problems you'd be better off avoiding. It also cements copper, which you'd be well off to avoid. That's why I suggested copper. As patnor suggested, a few ml of solution would have been satisfactory. All you would be looking for is a reaction with the copper wire to help determine if you have a problem with nitric, or not. There's no doubt it would cement the values.

Back to the aluminum, briefly. If you used too little aluminum to fully cement all the values, you likely cemented some copper too, which, in turn, would cement gold, so if you still show traces of values in solution, it's possible you have pretty well cemented almost all of the gold, but nothing more. Otherwise, the solution would test barren, and you'd find traces of copper in the solids.

The reaction you described with the added piece of copper is pretty much what you'd expect if you had a reasonable amount, or no free nitric present. If you have the ability to heat the solution (the one with the copper wire), that would help determine if you have excessive nitric, or not. A hot solution will be far more reactive than a cold one.

If you see no brown fumes, you likely have little of no free nitric. Armed with that idea, and the fact that it won't precipitate, I suggest you allow the copper to cement all the values, then start over. Working with relatively pure gold is always easier and more fun that working with dirty, murky solutions, anyway.

Keep us posted-----and try to remember---garbage in, garbage out. Eliminate as much of the base metals as you can before ever dissolving values. It's the smart thing to do.

Harold
 
Thanks Harold
I have about a third of a 2 gal bucket of the Blue solution which I have not done anything to but put in the copper wire. It still tests BLACK when I test it with Stannuos Chloride. Its been sitting over night. I will heat it today (with the copper wire in it) first and see what happens. Then I shall start all over using .5 lb of sodium nitrate disolved in 2 cups of water, add it to the solution, and then add 3 cups of HCL and see if I can restart the process. If I get the brown orange fumes, Maybe there's a chance to save it??? I just hate to quit without learning something ,,,, I know we could all benefit from my mistake.
Thank you for your patience
Robert
 
Hello Robert,

You mention a blue solution, which for me, too, shows the presence of copper, but as well only minute amounts (if ever) of dissolved gold. Did you ever check the pH-value of the solution? It should still have a value of about 1 or less, that means, it should still show a strong acid reaction. Treating with sodium-meta-bisulfite (SMB) consumes acid. Did you heat your mixture after addition of urea and SMB? I ask you this, because urea reacts slowly with water, forming finally ammonia and/or ammonium ions and carbon dioxide, depending on the acid concentration of the solution to which it has been added, the reaction being much faster on heating. In fact, calculated amounts of urea can be used in several processes to neutralize an excess of acid, forming it's ammonium salt. Excess HCl for example is neutralized according to the following stoichiometry: (H2N)2CO (urea) + H2O + 2 HCl => 2 NH4Cl (ammonium chloride) + CO2. If more urea is present, in addition, ammonia will be formed, which is a good complexing agent for dissolved copper, forming more or less dark blue coloured copper-solutions, sometimes together with a precipitate of finely divided pale blue copper-hydroxide (Cu(OH)2).

freechemist
 
thehorseline said:
Thanks Harold
I have about a third of a 2 gal bucket of the Blue solution which I have not done anything to but put in the copper wire. It still tests BLACK when I test it with Stannuos Chloride. Its been sitting over night. I will heat it today (with the copper wire in it) first and see what happens. Then I shall start all over using .5 lb of sodium nitrate disolved in 2 cups of water, add it to the solution, and then add 3 cups of HCL and see if I can restart the process. If I get the brown orange fumes, Maybe there's a chance to save it??? I just hate to quit without learning something ,,,, I know we could all benefit from my mistake.
Thank you for your patience
Robert
Click to expand...
It has been my recommendation that you use only small quantities of the solution for the purpose of testing. No harm done, but to expect a small piece of wire to cement all the values isn't reasonable. While it may have the capability, the time involved will be prolonged considerably. Cementation is greatly accelerated by presenting more surface area. Once you've understand where you are with relation to the solution, you may wish to pursue a different route.

It's not clear to me that your intention is to start over with the existing solution, or not, but if that's your plan, I'd advise against doing so. You'd be far better served to cement the values and process only them. The purpose of the test was to make a determination of the excess amount of nitric that may be present, nothing more. Cementation, for the most part, will work under almost all conditions.

One thing to consider, and it's important when cementing silver. As wire reduces in cross section, it tends to break apart in small pieces. If, once all of the values have been cemented, all of the wire hasn't been consumed, it can be difficult to remove from the cemented values. Not too much of an issue with cemented gold, for it can be dissolved with nitric, but when processing silver that's not an option, and any remaining copper tends to undo the work you've done in trying to eliminate base metals. My recommendation is to not use wire when cementing, but pieces that are easily retrieved when cementation has completed.

Harold
 
Dear Harold and Freechemist:
Thanks a million for all the good information and time you have spent on this tedious issue. Very Little success I would like share with everyone for what its worth. I put a piece of copper wire into some solution 200cc and heated it for 45 minutes. I also added 10cc of hcl and a couple of drops of sulfuric. Took it off and it tested well. I added urea a little at a time until there was no more fizzing. I then added the SMB and heated it again for 10 minutes. I found some brown mud on the bottom,,,, not much but some. To me that is some success a lot better than the gray very fine powdery stuff that I had before. Its still not what its supposed to be. I know its my fault for using aqua regia when processing cpu's. I bought sodium nitrate and msb from 2 sources. One from a lab and it is wonderful to work with. The other I bought from a fellow on ebay,,,, and I dont think it is any good at all,,, every time I use his chemicals something goes terribly wrong. this was one of them. I will go back to the drawing board,,,,as Im determiened to work with the same stuff for a little longer. Eventually if I dont get anywhere I will move on and chalk it to experience. Thank you all for your patience
( A Very Greatful) Robert
 
Robert,
The mud you found in the bottom may well be gold. Does your solution test barren? If not, please try adding a little more copper, so there's more surface area for the reaction to take place. You should be able to make a full recovery of the values this way, regardless of what you've done.

If, however, you fail to recover the gold with copper, all is not lost. You can use scrap steel, or even zinc, to recover, although you'll also recover the copper. Not a problem, however, in that you can incinerate the recovered solids, then start with nitric to eliminate the copper. That should leave you with quite high grade finely divided gold, which you would then process, sans the overwhelming amount of copper.

If you are not enjoying success with the precipitant you're using, you may wish to give ferrous sulfate a try. It's painless to use and easy to buy from a good garden supply shop. Look for iron for plants, and ensure that the contents are green, not brown. If you have not included excessive nitric in your solution of values, an ounce of ferrous sulfate crystals will precipitate an ounce of gold. Simply dissolve the crystals in clean water, using just enough to dissolve the crystals, then drip several drops of HCl in the solution. Watch for the solution to "brighten" in color, which well be a very pale green. When that happens, pour the solution in to your filtered gold chloride solution. You should experience an instant cloud of gold. Test after to ensure that you have a barren solution. If not, use more ferrous sulfate.

By the way, I hope you've learned something from dissolving everything instead of eliminating base metals first. That's a very important lesson to learn.

Harold
 

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