# Poorman's AR



## glondor (Mar 30, 2011)

RE: step 9 in the poormans tutorial>>>"If salts form pour off dark acid through tight filter and start at step 3 above. Filter may contain gold foils or powder".<<<

If the filter contains gold foils or powder, should these be added back to the CPU pot for digestion along with the rest of the gold? or should they be set aside for digestion with hcl/bleach later.


I am doing a couple of pots of cpu's that were stripped of pins and base metals using acid/peroxide in February. There is not much gold on them and my Poormans AR is light green. I have filtered a batch to crystal clear and I killed any nitric with Harold's trick with the gold button.It lost .05 gram overnight. It is dropping now. 

I am filtering my second batch and it does have some powder in it. This is why I ask.

I did not get any salts forming. Added Potassium Nitrate very carefully.


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## lazersteve (Mar 30, 2011)

I usually wash the foils from the filter back into the reaction pot before the final AR treatment when all of the gold is to be dissolved on the final run.

If any traces stick to the filter paper toss it in your gold paper waste incineration pile for recovery later when you have enough filters to warrant processing.

Steve


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## glondor (Mar 31, 2011)

Here we go! a nice little 11.38 gram button from Lazersteves poor man's A/R.Thanks for the help guys. Now if only I could make 1 of these a day...


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## glondor (Mar 31, 2011)

Got to work on the second batch today. Not sure why, but I cannot seem to find the gold. The only difference between this batch and the first is it sat 1 extra day. 

Both batches were done at the same time with Poor Man's AR. First batch gave me the 11 grammer pictured above.

Second batch is neg for gold with stannous after SMB however there is no precipitate. AR is "dirty oil black" I have put a gold button in again just to make sure all the nitric is gone, However I did put it in overnight and it did not loose any weight.

Filtering leaves the grey/silver mud as usual, I don't know where the gold is. 

Is there something I can try or should I just cement with copper and have a "do over"


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## Oz (Mar 31, 2011)

It is most likely that you did not completely digest all of your base metals in your second batch. So your gold cemented on what base metal is remaining and is now part of the sediment on the bottom of your beaker.


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## glondor (Mar 31, 2011)

Thanks OZ, That seems to be my trouble, there is no sediment. Just the usual silvery/grey mud in the filter. I am puzzled. I will go back through my material and look some more. 

Most of the base metals were removed when I did the A/P on the pins several weeks ago. There was some gold on the CPU'S. I did not segregate the two batches, so they should have roughly equal amounts.

Side note....
Those darned pins are still fighting with the HCL in a pail. They will not give up!


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## dtectr (Mar 31, 2011)

glondor said:


> Thanks OZ, That seems to be my trouble, there is no sediment. Just the usual silvery/grey mud in the filter. I am puzzled. I will go back through my material and look some more.
> 
> Most of the base metals were removed when I did the A/P on the pins several weeks ago. There was some gold on the CPU'S. I did not segregate the two batches, so they should have roughly equal amounts.
> 
> ...


I have learned that many pins, especially if they're formed or stamped, are made of phosphor bronze, the trouble-maker there is the tin (3-10%) from the bronze. Exposure to nitric & heat, even that formed with Poor Man's AR makes a sticky jelly known as metastannic acid. It doesn't dissolve in ANYTHING - incineration then hot HCl, according to Harold, should help, though it didn't for me (Then again, lots of stuff happened on this last batch).

The tin "jelly" coats everything, even the gold you're trying to digest, to the extent that it is shielded from complete digestion, at least in my recent batches. Anyway, heating metastannic acid to red heat (approx. 700* C) long enough for all to react converts the metastannic acid to tin oxide, which will dissolve in concentrated HCl or Sulfuric.

Colorwise, I've seen everything from green, grey to tannish. May or may not be your issue, but its probably good to know.


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## glondor (Apr 1, 2011)

I got nothing. Going to try cementing with copper.


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## shyknee (Apr 9, 2011)

glondor said:


> Got to work on the second batch today. Not sure why, but I cannot seem to find the gold. The only difference between this batch and the first is it sat 1 extra day.
> 
> Both batches were done at the same time with Poor Man's AR. First batch gave me the 11 grammer pictured above.
> 
> ...


did you find your gold :?: 
did you test your filter with the grey/silver mud for traces of gold :?: 
if there was any metals or powders in your AR before you filtered then the gold could have plated back on to the metal bits (hope you did not throw out)


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## Harold_V (Apr 10, 2011)

glondor said:


> I got nothing. Going to try cementing with copper.


Surely you've heard of stannous chloride for testing?
If a test is negative, there's no reason to try copper (assuming you don't have a large excess of unused acid present). 

Harold


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## glondor (Apr 10, 2011)

Thanks for your input and interest guys. I had to redo the process as i could not find the values on my first try. I did cement with copper and got some black powder. 
Stannous test on the used filter turned the whole filter purple.
Stannous test on filtered liquid resulted in brown on spot plate turning to bright yellow over night. 

I do not understand what happened. There for I cemented the liquid to do over and processed the filter in hcl/ bleach.

Why 2 very similar batches behaved so differently I do not understand. 11 gram button from 1 batch and confusion from the next. The only real difference between them is batch 2 sat overnight as it was too late to begin with it. 

recap: 2 pots, 2 lots of similar material. (ceramic cpu) Same volume water, acid, potassium nitrate. Both pots heated at the same time in an electric skillet, same addition of nitrate (1 additional teaspoon each) Denoxx with gold button, added equal volume of water, Gold dropped with smb. 1 expected result and 1 not.


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