Poor Man's AR for Ceramic CPUs

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Sounds like regular AR is just a little easier to use. Do you have any data on the cost advantage...if any?
 
hoardpm said:
Sounds like regular AR is just a little easier to use. Do you have any data on the cost advantage...if any?

Hoard,

The real difference lies in the ease with which the fumes and nitric additions can be controlled. I suppose there may be a cost savings relative to liquid nitric acid as you are not required to pay hazmat shipping costs on sodium nitrate.

As for the actual required mass of sodium nitrate verse 70% nitric acid here's the data on that topic:

Nitric vs Sodium Nitrate

Steve
 
Are there any other common nitrates people could use for poorman's AR?
I'm specifically interested in ammonium nitrate.
 
Steve, i would like to point out a basic subject which collide with my general understanding.

you presented the recipe for poor man's AR, which is' in short, dissolving gold along side with the base metals tha are on/in the CPU's, this contradicts with the ongoing preaching for dissolving base metals first and then the gold...

is there something i didn't understand in the process the you introduced?
it that process can be done with HCL+Cl ? on fingers... pins (tryed that BTW), flat packs, black IC's etc'...

generally i prefer not to introduc nitric acid to my workshop

Thank you for your answers.
SAMUEL
 
Sam,

In this step wise process you will notice that the gold foils do not remain in solution while the process is proceeding. Instead the base metals, when present in large proportion to the gold, always keep the gold (both in powder form and foils) out of the solution. This is because the HCl to nitrate ratio is much greater than in normal AR and the base metals saturate the solution acting as a precipitant. The nitric is consumed by base metals as it is produced once the gold foils are penetrated.

In essence this reaction is slowly producing nitric acid 'in situ' (in solution) which dissolves the base metal's and not the gold. As the reaction progresses and the base metals saturate the HCl solution, you will pour off the saturated HCl and nitrate solution (always test for dissolved gold) and start with fresh HCl.

If you only add small portions of sodium nitrate in each addition, the NOx fumes will be minimal.

On the last cycle of this process (three to four cycles with kg quantities of scrap) you will finally dissolve the gold along with the last of the base metals. Filter out all particulate, then add SMB, followed by HCl wash cycle and finally redissolve, filter, precipitate, and wash a second time for high purity gold.

HCl-Cl is not as aggressive as nitric acid or AR towards base metals and therefore is not suited to this step wise style of reaction.

If you want to avoid NOx fumes then you should look at the reverse plating cell with a copper basket or the AP reaction for larger batches of pins.

Steve
 
Thank you steve for clearing that out for me.

now days i'm using Ap for fingers and unpopulated boeards that contains foils.
also for pins, but come to a conclusion that it's just not effective to do so... so now, i'll use this method only for the very small scale pins and left over from the dismantling.

i just finished up sturate my CELL.
diluted yesterday (1:2.5 ratio)' i'm gonna wash with water 3x and then HCL 3x
would you recommend hot HCL wash?

i don't have at the moment ammonium hydroxid or nitric acid to add to the washing phase...
i understand i'm risking having silver in my powder? correct?

should the powder from the cell be dissolved (HCL+cl) or just wash and melt?


Thanks
SAMUEL
 
sam said:
diluted yesterday (1:2.5 ratio)' i'm gonna wash with water 3x and then HCL 3x
would you recommend hot HCL wash?
Sam, Wash with water, then let settle until the color of the wash water is no longer blue. If you want to be extra clean test a few drops of the rinse water with a drop ammonium hydroxide (3% unscented household ammonia will do), a blue color indicates coper is still present and you should wash some more. After the water rinses hot HCl and water rinses are good.

sam said:
i don't have at the moment ammonium hydroxid or nitric acid to add to the washing phase...
See note above about 3% ammonium hydroxide, you should be able to get it in any grocery store. I personally don't wash with nitric any more at all.

sam said:
i understand i'm risking having silver in my powder?
Yes, cell powder may contain some silver.

sam said:
should the powder from the cell be dissolved (HCL+cl) or just wash and melt?
Depends on your goal:If you want pure gold then dissolve, filter free of particulate, and precipitate with SMB.

If you don't care about the purity, just melt the powder. If you just melt the gold you may find it has a dark crust or other odd appearance. This contamination is not just a crust even though it appears to be such. If you sand it off and remelt the gold, the crust reappears.

Here's a link to a previous post on cleaning up the powder from the cell:

Cleaning Cell Powder

Steve
 
Thanks steve... you just have everything ready in your sleeve :)

i'm looking for pure gold as i can create, but afraid i'll mess it up...
i understand that the more pure the gold is the more closer to the spot i'll get... isn't it?

well, i have rinsed the main bolk of black powder from the cell only with distilled water until 'clear', the filtration gone well and the water came out without any powder (whatman filters are the best).
i'll let it settle for tonight in water.

the second bulk (much smaller of course) came from the washing vessles of the pins and baskets.
rinsed 3x with water until clear, then 3x with HCL at room tmp", the last wash i let settle for 20 minuts, boy, that's a stinker... any way, the hcl wash came out pretty clean and clear, though it did got a little goldish color to it, i have yeat to test it for gold presence.

the two bulks of powder were combined and sit in water as mentioned above for the night.
the powder contains a few non PM very tiny objects (pices of pins and silicon waffers)

next steps:

1 - boiling with HCL ----> 3x water rinses
2 - Incineration
3 - dissolving with HCL+Cl -----> filter
4 - droping with SMB

i'm sorry for digging your mind for my gold, just... i wnat to be sure with my next steps so i'll present a few more questions


1- can i rest assure that boiling in hcl will not dissolve any gold?
2 - about the Incineration, should it be done by a turch directly on powder or in a pan above a flame? (generally, whay to Incinerate)
3 - i have no way of knowing how much powder is in there, according to my mesurments, there is around 80 grams of black powder... but, this does not sound reasonable to me, as i prosseced 1 Kg of medium grade pins and 20 or so CPU's... anyway, after dissolved and filterd, how much SMB should i add.... (40% SMB solution)?
5 - i have for now only less then a liter of an allready prepared 40% SMB solution.... this means that i don't need to dilute the AuCl3 before droping ?


many, Thanks again
can't wait to show here my final results.
SAMUEL
 
The next steps you posted are good.

HCl-Cl will require some heating and lots of stirring to get the gold into solution.

Diluting the AuCl3 is not required, but helps force any traces of silver chloride out of the mix. If you see a cloudiness after diluting, be sure to filter out the sediment befroe adding SMB.

Using SMB is not rocket science, just add it in small increments with stirring. When the gold powder settles test the solution with stannous. If positive add a little more SMB and stir. I use it dry, but a concentrated solution is fine also.

Incineration is performed in a large melting dish or rectangular silica dish.

Judging from the amount of scrap you processed you should expect more than 2 grams and less than 10 grams of gold.

Steve
 
well.... a little update

i apparently miss the part which u said HCL+Cl will require heat also... i did stirred alot with my magnetic stirer though, and got a real nice rich golden color to it, so i guess i managed to saturate the solution.

Q. - what's maximun ratio between HCL to Cl would you recommend?

it finally dissolved completly after 3 re-fills and ended up with 2 liter (0.528 galon) of AuCl3 without diluting.... ( is this reasonable amount? )

after dissolving all of the gold, i was left with quite a few impurities in the form of gray powder, cement like texture...

the SMB wasn't even near to enough , and i ended up adding 800ml of 40% SMB solution, which, after alot of stirring and setteling, precipitated only a bit of gold powder.... and the solution is still dark yellow-green.
now i'll have to wait for next week until i get some more SMB, because back here, i cannot find it in kmart like stors... ( maybe some brand name that i don't know of? ) only at chimicals dealers which is far away....

BTW, what are the fumes (and terrible smell) that is coming out whan addind the SMB ?

next update , next week.
Thanks, SAMUEL
 
samuel-a said:
BTW, what are the fumes (and terrible smell) that is coming out whan addind the SMB ?
My money says its SO2, but I wonder if it's possible to create hydrogen sulfide by this process? Could prove deadly if you breath much if it is.

Seems to me you must eliminate any free chlorine in order to achieve a fast and good precipitation of gold. Could be wrong, however, considering I never used this particular process.

Harold
 
Harold,

You are correct, the free chlorine levels must be lower with gentle heating before adding the SMB. Alternately one could let the solutoin sit in the sunshine to destroy the free chlorine.

Steve
 
Steve... Im in big truble here...
the gold doesn't drop...


i finally got a hold of SMB (Molecular formula - na2s2o5), 55 pound for 27$
i have dissolved 100 grams of SMB in 250 ml of distilled until saturated or very close to it.... (by wiki - 54 gr to 100 ml)
dump it to the AuCl3 which was splitted dou to the lack of space in the main vessle, and.... nothing but nasty sulfor gas.... the solution remains the same rich golden color, positive for gold naturally, and just a little bit of black powder on the bottom

i'll review my steps:
1- collected the powder from the CELL
2- rinsed with water 3x and hot HCL 3x
3- again with water 3x
4- dissolved with HCL+Cl which i needed to do 3 times over in order to completly dissolve all of the gold and ended up with 2 litre of AuCl3 without any water dilution. (i have decided not to Incinerate, because i don't know how... and more important, don't know whay?)
5- filterd (left behind a lot of gray paste like matirial... some of it is silica i know, but the rest i have no idea)
6- let sit for the night in hot water bath
7- added 800 ml of 40% SMB solution, got me only a small precipitation (again, the AuCl3 was not diluted with water).
8- split the AuCl3 to two parts 1.4 +- litre each
9- added 250 ml 0f saturated SMB = nothing , added more 250 ml = still nothing.... same as with the other half of the batch...


i have gone almost comletly by the book... what is wrong?
i think 200-225 grams of SMB should drop a few grams of gold... isn't it?


i would really appreciate any help from any one
Thanks
SAMUEL
 
in top of every thing, i tried to dilute and then drop....

200 ml of AuCl3 + 200ml of water + 100 ml sturated SMB solution

5 minuts over magnetic stirer, as usual... nothing happend...


here is the stannous chloride test of that dilute solution after SMB and stirring:

came out brown to orange like in color and faded away complitly after a minute or so.
View attachment 1

i might add, that after dossolving the gold, the stannous test was perfecly purple/black indicating a lot of gold...
here it is:


the initial 40% solution is actually just sodium bisulfite (NaHSO3) that did the actual first small dropping from the gold... any way, the function is the same as far as i understand... introducing SO2 to AuCl3
 
Sam,

Evaporate the solution down to 1/3 of it's volume or unitl you see salt forming.

Let us know what happens and the results of your stannous test after that.

Have you recovered any gold at all from the batch ?

Steve
 
not yeat... i do have some black powder on the bottom, but still didn't treated it.

i still need to get my hand on some electric hot plate and big enough payrex vessle, so until then i'm stuck with it.
i'll let it sit until sunday.
then siphon and collect the black powder that did precipitated and update here.

this is an extremly odd case...
i took a small smple of the AuCl3 and exploded it with SMB... all i get is far more brighter yellow color to it....

beside that... do yu have any more suggestions based on my findings?
 
samual-a

Are you using the dilute HCL 10% you mention here?

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=5830&p=52103#p52103

If I remember correctly SMB reacts in an acidic solution.

Steve is it possible his HCL is depleted? or possibly buffered in some strange way?
 
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