AR Issue...

[IGutYa]

ok, i ended up getting some ebay scrap, 5lbs, including plastic, of 14k plated fingers, about 8oz of fingers alone, and decided to have a go at it. Well....

...all was well up to a point. i did the hcl h2o2 de-plating, filtered & washed the remaining gold specks. it weighed in at 1.29 grams. so i proceeded to measure out a 4:1 AR ( hard to do in such a small amount) & dropped the gold in. stirred & let it sit a bit & didnt really have much going on, so i threw it on the hot plate to heat things up. right as the surface started to boil it took off & made some NO2 and eventually quit. i let it simmer for a while longer just to make sure & let it cool down.

at this point i added in aqueous SMB slowly with alot of stirring. after adding in about 3g's worth of SMB that i had dissolved in distilled water, no gold had dropped =( tried a little SMB powder, and nothing. S#*t. now i have a glass of dissolved gold, smb, and some hcl with no way to get the gold out.

so now what? can i still salvage the original 1.29g of gold? or is it lost?

 

[Buzz]

Sounds to me like you forgot to boil the solution down to get rid of the nitric.

When you threw in the SMB, your Gold would have appeared but got redissolved by the AR.

Boil your solution down until it turns syrupy and add a small amount of HCl.
Boil down again and add a little more HCL.
I do this three times to be sure.

What you have now is a solution free of Nitric, therefore it's not AR.
Dilute with water to 4 times its volume and then use SMB.
Your brown/black powder should appear and settle to the bottom.

If your foils only weighed 1.29g, you're not going to see much powder.

Buzz

 

[nickvc]

Reckon Buzz is right here the nitric is your problem,my advice is to do exactly what he suggests and your gold will staring at you in the bottom of your beaker in no time 8)

 

[Oz]

If you overdosed the SMB trying to get the gold to precipitate the same as you did the nitric it will be a bear to triple evaporate it due to all the sodium chloride trying to crystallize out.

 

[butcher]

What would Harold tell you?

Maybe he would say to add some gold to the boiling solution.

 

[Harold_V]

What would Harold tell you?

Maybe he would say to add some gold to the boiling solution.

Or, cement with copper and start over.

Harold

 

[Oz]

Cementing gold in AR on copper is not much fun either. At least I never liked it. It is slow and gives a very fine black powder precipitate.

 

[IGutYa]

ok, i went with the advice of buzz & boiled it down.... i hope i didnt screw it up good lol.... when it got down to a thick liquid i turned off the heat & next thing you know it was bumpin hot stuff all over the place. after that subsided i was left with a white & brown-gold crystalline mass. hoping i didnt screw the pooch i went on ahead and added in some hcl slowly. it reacted and turned into a green liquid. it had some chunks in it so i added a little distilled water & now it is a pure green liquid with no chunks.

so, since it accidentally boiled down to powder, do i need to reboil it & do it all over again? or should i wait for it to cool down & add some more smb?

 

[butcher]

not sure I understand where you are with this? but if it boiled to salt (dry), you may have made a sulfate, the nitrates boiled out, the chlorides boiled out, and unless the salt was roasted you had sulfates salts from the SMB, this is further complicating the situation.

is this all solution or is there any powder? the green color leads me to believe you have copper in solution, have you tested the solution with stannous chloride?

I think you should test solution if your gold is there then take Harolds advice, READ HOKES
and copper to cement, after you read Hokes, then try again.

 

[Oz]

I am rather sure he lost some gold to the bumping, then he lost some more gold taking it to a dry chloride salt. Having said that if he has taken it all back into solution with HCl and water with no particulate matter present he should be good to go just precipitating with SMB.

 

[IGutYa]

not sure I understand where you are with this? but if it boiled to salt (dry), you may have made a sulfate, the nitrates boiled out, the chlorides boiled out, and unless the salt was roasted you had sulfates salts from the SMB, this is further complicating the situation.

is this all solution or is there any powder? the green color leads me to believe you have copper in solution, have you tested the solution with stannous chloride?

I think you should test solution if your gold is there then take Harolds advice, READ HOKES
and copper to cement, after you read Hokes, then try again.

well, i realize my mistakes at this point & accept that i screwed the pooch on this one.

the reason it dried to a powder was when i turned the heat down a little so i could add more hcl it strangely flash-dried. i had no control over it. it went from a brisk boil to a dry solid when i turned the temp down a quarter an inch. bumped & spat acid sulfate all over the place (fume hood =) what a mess. when i re-acidified it with hcl it fizzed & turned back into the original color. added some water & started to reheat it. color turned to a nice golden yellow & did a stannous chloride test & it was dark purple black, so i figured it was still there...

needless to say upon trying to do the 3x boil down i didnt consider just adding more hcl without changing the temp & so it flash-dried again, and by the looks of it, it exploded. but i know better cause i was there, just Severe bumping. covered it with some paper & saved a good bit of the powder. most is a golden dust & some is a darker chunk.

quite honestly im ready to start over. next time i think ill try the hcl + cloroxl, it appears to have less of a chance of jacking it up.

ive read hokes pdf a few times & watched all of steve's video's. this was my first attempt. i always do better the next time around.

 

[butcher]

you usually will not boil down to salt, just a thick syrup.
and now you see how a hot solution will hold more metal salts than a cool solution,
it does not sound like you dried it completely out (driveing off all chloride as gas), so the gold was most likely still a salt of chlorides, and they dissolved back into solution, this wont be your last accident with gold solution's.

 

[IGutYa]

you usually will not boil down to salt, just a thick syrup.
and now you see how a hot solution will hold more metal salts than a cool solution,
it does not sound like you dried it completely out (driveing off all chloride as gas), so the gold was most likely still a salt of chlorides, and they dissolved back into solution, this wont be your last accident with gold solution's.

it was dust when i added more acid. as soon as i changed the temp it flash boiled. i have the very same dust from the second time i tried adding hcl. what a mess.

 

[butcher]

acids can react violenty with powder, I usually add some water and use a plastic eye dropper to add acids or oxidizers slowly till I see how much reaction or things settle down, even trying to pour a few drops from a jug can spit violenty at you.

 

[IGutYa]

acids can react violenty with powder, I usually add some water and use a plastic eye dropper to add acids or oxidizers slowly till I see how much reaction or things settle down, even trying to pour a few drops from a jug can spit violenty at you.

yea ive become rather aware of how well it can spit on you.... ill have to take a picture of my fume hood. what a mess. i think when i replace the doors im gonna do the glove-in-the-window setup so i have a full shield.

....and how NOT to make a fume hood. needless to say, my original design was blowing all the fumes in the wrong direction. the design was right, sorta. tried to do an s-type eductor design, thought it was working pretty good.... bad bad bad.