Help with Precipitating Gold from HCL/Clorox

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nateatkins0120

New member
Joined
Jul 8, 2014
Messages
4
Hello all, I have been reading this forum for the past few weeks, which I understand is just a drop in the bucket, and I have read Hoke's book which has taught me a great amount, excellent resource to say the least. The reason for the post is that I used the AP process to get gold from old computer and other electronic sources, and that worked great, I then dissolved the gold in HCL and clorox, after of course 3 HCL and 3 water rinses.

I then waited 24 hours so as to let the free chlorine escape, the next day I went out and tested the liquid with Stannous chloride and it went black which to me indicates the presence of gold, so I diluted the mixture 3 times as per laserSteves website video and I used about 2 grams of SMB to precipitate out the gold (I am expecting about 1.5 grams). Nothing happened, at all.

So I did some research on this forum and I decided to heat the solution and did so for a few hours, afterwards I tested again with stannous and still had a black mark, so I tried again to precipitate with 2g of SMB. Nothing happened at all.

Then I tried heating and reducing (never boiling) the solution and then adding some HCL to it to increase the acidity and then adding some more SMB but again nothing happened, at all.

I am just wondering what I am doing wrong or if there is anything I can do just to start all over again in dissolving the gold. Now just so you know I read somewhere here to waft the air towards you to see if you can smell chlorine and there is no smell to chlorine at all.

Any ideas? I'm at a loss of what else I could try.

Thanks in advance for your help.
 
What is the source of your SMB? Is it fresh? Are you certain it's sodium metabisulfite?

Since you've added a fair amount of SMB with no reaction, this might be a good time to recover the gold by cementing it with copper, then refining it a second time.

Dave
 
I can't be 100 percent sure if its fresh or if its sodium metabisulfite but that's what it says on the label, I bought it from Amazon about 2-3 weeks ago in preparation for the refining process, it just came in a small bag with a printed label, almost as if it had been taken from a larger source.

At this point I may just throw a copper pipe into the mix like you have suggested and start over from square one. Thanks for you're quick reply and helpful information Dave it's much appreciated.
 
If you're using SMB and it's fizzing, going cloudy, and still not precipitating then it sounds like you've got chlorine still in your solution.

Every time you use some SMB it will produce the Sulphur Dioxide needed to precipitate the gold but then if there is Chlorine still there it will redissolve. An alternative to using copper is to put an excess of SMB in the solution. Try 4g at a time. Let any reaction finish before putting any more in. This will cause the gold to be cyclically precipitated and redissolved which then use up the excess Chlorine in the process.

Note you do run the risk of forcing the gold to drop and pull down any copper in solution by doing this, but at that point you follow Harold's clean up process with HCl/water washes.

You will know exactly when the Chlorine has been used up because the solution will most likely darken rapidly.
 
That's the weird part is when I put the SMB in the solution I don't even get any fizzing of any kind, no cloudiness or anything, it just dissolves without any reaction, Im starting to think that the SMB is the problem, I may have gotten an older batch.
 
Try taking a very small amount of your raw HCl and adding some SMB to it. Does it fizz?
 
I still have problems with hydrochloric and Clorox. I had one problem that I struggled with and I am still not sure what happened. To make the drop work, I let the SMB heat gently making sure the SMB was used up as well the Clorox, (edit: I heated the solution that had the SMB added to it) got a clear stannous positive result, then added a small amount of HCL. When I added the SMB the second time it dropped right out. Mine was a fairly dilute solution and I have always wondered if that was the problem. The SMB seemed to fall to the bottom and do nothing but dissolve. I am still learning so I am curious to see what your out come will be for your particular problem. The idea of dropping everything in solution will work, I did try a small sample and it seemed to work real good, and no problems came from refining a second time.
 
SMB is soluble in water. It needs to be in an acidic solution to decompose into sodium (in this case the sodium takes a hydrogen chloride atom and is converted to sodium chloride) and SO2 gas. The hcl is needed to break that chemical bond. If the solution is not acidic enough, the powder will just dissolve without decomposing.
 
Too much water and not enough patience.

Test the Ph to make sure it's acidic and then wait a day or 2. Check PH again and then add some more SMB and wait.

I have had lots of trouble like this when washing gold trim from glassware. Impatience is hard to overcome. And adding to much bleach or water bringing the PH up causes drop less solution.

B.S.
 
I had a similar experience from gold chloride in a close to neutral solution. When I added HCl the gold dropped.
Pantherlikher raises a valid question, adding bleach (which is basic) to a weak acidic solution could raise the pH above neutral and that would probably stop the precipitation of gold.

Do a small scale test on a tiny sample.
- Take a few drops of the pregnant solution in a spot plate or white plastic spoon.
- Add a few drops of HCl.
- Dissolve some SMB in water and add a few drops.

Even if you don't see any black sediment the gold might have dropped out so test the resulting liquid, it should be barren.

You should also test your SMB. If you drop SMB crystals or powder directly into HCl it should fiss when giving off SO2. Be aware that SO2 is dangerous so do this outside or in a fume hood (that goes for the gold drop too). When I did my first gold drop I didn't know that and the first whiff of SO2-gas gave me an instant asthma attack. I could hardly breath for 20 minutes.

Göran
 
Thanks for all of the help and suggestions, I put the SMB into straight HCL and it fizzed so that should be good, I also separated off some of the liquid and then added some HCL and then some more SMB but still no drop. I definitely wish I would have read more on the SO2 gas because I had the same experience as I caught a good whiff when the breeze changed direction. As for the solutions, I was unaware it could take so long, it being my first drop, my patience is a bit shortened in anticipation. But what I have done is just added way too much SMB, I have way too much liquid now, and so I decided to cement out all of the metals and re-refine the metals.

It seems to be working well, although I notice that the cemented metals are sticking to the copper pieces I placed into the solution, so I am going to do some research on how to get it off the copper pieces. But for next time I'm going to place a lot more importance on keeping an eye on the PH level, Adding only a bit of SMB at a time, and exercising more patience.
 
Very interesting thread guys. I am still self educating and collecting foils, building a sulphuric cell but have wondered which way I will go when I get to the day of dissolution - HCl/Clorox or AR, I can do either but would prefer to reserve my HNO3. This has been an eye opener for me when I see that senior members have had problems with the former and the comments/advice given has been very helpful if I choose to go that way. Nate - I hope it works out for you. If you think or it proves out that your SMB is weak, dated, whatever - you can get this stuff at any winemaking supply shop. That way you can ask the vendor about the freshness of the product, source, etc.. Not sure but may be cheaper than Amazon also.
 
If you use a large flat thick bar of copper, you can just brush the gold off into solution, the gold does not plate well to the copper in the slution, so you can easily brush the black powders off with a brush like a clean old tooth brush.

Using the acidic solution to clean the gold bar, rinse the brush off in the solution, and and tap the brush handle on the of the jar, to clean gold from its bristles, rinse the brush and the copper bar off with water, back into the jar, and dry the copper and store it in a plastic bag to help keep it clean and from oxidizing so badly, so you can use it next time you want to cement values from a solution.
let the powder settle well before decanting and filtering the solution, and test the solution for any gold that may still be dissolved in it...
 
butcher said:
If you use a large flat thick bar of copper, you can just brush the gold off into solution, the gold does not plate well to the copper in the slution, so you can easily brush the black powders off with a brush like a clean old tooth brush.

Using the acidic solution to clean the gold bar, rinse the brush off in the solution, and and tap the brush handle on the of the jar, to clean gold from its bristles, rinse the brush and the copper bar off with water, back into the jar, and dry the copper and store it in a plastic bag to help keep it clean and from oxidizing so badly, so you can use it next time you want to cement values from a solution.
let the powder settle well before decanting and filtering the solution, and test the solution for any gold that may still be dissolved in it...
Click to expand...

He meant copper!
 
I meant to type, Using the acidic solution to clean the clean the gold off the bar.
I have been having a hard time with my computer, freezing locking up, and it has not been recognizing about half of my keyboard strokes.
 
butcher said:
I meant to type, Using the acidic solution to clean the clean the gold off the bar.
I have been having a hard time with my computer, freezing locking up, and it has not been recognizing about half of my keyboard strokes.
Click to expand...

I had this problem with 2 of my used and abused computers. Screen freeze, restarting when it felt like it. Etc.
I accidentally found the problem to be loose/dirty connections for the memory. Those shiny fingers not making good contact I'm guessing.
I pulled all the memory thinking a bad stick(2 sticks). Put 1 back in and it worked perfectly so put the other 1 back in and didn't have a problem again for another month or 2 or continuous running.

Can't hurt to try it.

B.S.
 
Butcher,
Ive been building my own PCs now for over 20yrs. Im running a CPU water cooled gaming beast now.
Memory module corrosion might be a possibility but, the fingers are Gold & that does not corrode easily unless its parked by your refining work which I doubt, my bet is you probably have a tired ol wornout keyboard.
Id buy a cheap keyboard online & give it a go. Ive had several keyboards go fubar on me and the issues were the same as you are having. If re-setting the memory does not work it would be my next choice. Might want to go into control panel & also remove any non essencial softwares also. I do that monthly, some beta softwares don't jive well with other programs. Sys. will run best on minimual HD downloads less clutter & less bad interactions.
Dave
 
Butcher, when you have the computer open, check for any "popped" capacitors. Especially around the CPU and any power electronics. Feel the top of any aluminum electrolytic capacitor to see if they are flat or starting to get a bulge. Bad capacitors is one of the most common problems in modern electronics. The problem (with capacitors) could also be in the power supply.

http://en.wikipedia.org/wiki/Bad_capacitors

Good luck!

Göran
 
Good tips, thanks everyone, as far as computers go I am a real bozo.

No telling on my old computer what files, or programs may be fighting with each other, my computer seems to have its own mind to do what it wants to, when it wants to.

Bad electrolytic capacitors also a real possibility, on this old girl.

I keep my refining way away from my house or my computer, the memory fingers did look clean, reseating them (or the other cards) did not help this time, but that was also a great tip, it just did not seem to the problem with mine.
 

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