Sodium nitrite to precipitate gold from A.R.

[HAuCl4]

GSP: I believe he is putting NOx into the flask...and that is precipitating the gold when it becomes nitrous acid???. Maybe I'm wrong. Not a very clear video.

Otherwise I do not see what the little rubber hose is accomplishing. :?:

 

[joem]

I would love to see the drop too.
Do you have that clip?
joe

 

[lazersteve]

I think the solution in the addition funnel is sodium nitrite and he is dripping it into the pregnant solution.

The pregnant solution appears to be green color to me.

Steve

 

[HAuCl4]

Kind of stating the obvious, but anyway: No need to expel excess nitric with this procedure. 8)

The HCl will become table salt, so you don't want too much excess in there!.

 

[SilverNitrate]

The sep funnel at the top has NaNO2 and water, The bottom is dissolved AU in AR along with mostly CU (this was dissolved karat jewelry). This must be allowed to drip slowly as it evolves alot of NOx gas. Since there is no (AU NO2) ie Gold Nitrates the gold simply falls out. The copper and many of the other metals does become nitrates (or ions) and stay dissolved which would easily be filtered and rinsed from the gold powder. It is uncertain about the other exotic metals such as rhodium and palladium.

 

[SilverNitrate]

Kind of stating the obvious, but anyway: No need to expel excess nitric with this procedure. 8)

The HCl will become table salt, so you don't want too much excess in there!.

You would have to rid at least most of the excess nitric because that nitrate will oxidize the nitrites releasing much more NOx gas. I generally rid most of the nitric in AR with NaOH. good to keep a sprayer of alcohol handy to rid suds.

 

[HAuCl4]

The idea/motivation behind my posting was to use a generally acceptable procedure (sodium nitrite is one of the reccomended precipitants in Hoke's book), but with the general intention to save/recover/recycle chemicals as much as possible to reduce waste and hopefully save costs.

As 4metals indicated, all the NOx expelled from the precipitation can be easily scrubbed in water peroxide "scrubber", which can simply be a series of tanks connected by pipes and filled with water peroxide, that is slowly transformed to nitric acid, with concentrations rising from the last tank to the first, and little if any NOx in the exhaust.

If one puts a Sx step before precipitation, one could even recycle the nitric acid in the clean soup after precipitation, and neutralize/discard the "dirty soup" from the base metals after Sx. This seems to me the less wasteful method of operation, with the final products being purified gold, recycled nitric acid, and table salt, and of course whatever base metal chlorides or hidroxides or whatever to be further treated/recovered or sent away for disposal (in a smaller quantity).

 

[peter nudo]

NO2+Water= Nitric Acid

Nitric Acid + HCl= AR

Some, if not most of your Gold is going to go right back into solution.

 

[Martijn]

and table salt,

I'm not following your theory here, but one huge alarm goes off: you don't produce TABLE salt from your chemical waste.

Street defrosting salt at best. Not for consumption..
I would discard it.

And YOU might think this isover obvious and overreacting... believe it or not, for some it will actually sound like a good idea to sprinkle that chemical waste over your eggs at breakfast.

 

[Yggdrasil]

I'm not following your theory here, but one huge alarm goes off: you don't produce TABLE salt from your chemical waste.

Street defrosting salt at best. Not for consumption..
I would discard it.

And YOU might think this isover obvious and overreacting... believe it or not, for some it will actually sound like a good idea to sprinkle that chemical waste over your eggs at breakfast.

He hasn't been here for 7 years.