Washing the black cell powder in HCL?

[husker4515]

I have completed every one of Steve's steps listed below, except for dissolving the black powder in HCL/Clorox. There was no mention of washing the black powder in HCL before going to the next step(dissolving the black powder with HCL/Clorox).

My question is do I ,and for how many times?

1. Let all the black powder settle
2. Pour off the bulk of the concentrated sulfuric acid. Don't worry about the small amount of residual black powder that is in the acid that is poured off as you can get it o
n the next batch.
3. The remaining acid with the bulk of the black powder in it should be slowly added (let it cool before adding more) to five or six times it's volume of water.
4. Stir this very well and allow to settle again.
5. Siphon off the colored solution. Repeat this process until the wash is no longer colored.
6. Test a few drops of the rinse water with a drop or two of 3% unscented clear household ammonia, if the rinse water turns blue when the ammonium hydroxide is added, copper is still present and more rinsing is required.
7. Dissolve the black powder with AR or HCl-Cl and proceed as typical for these processes.

 

[dtectr]

If I understand correctly, there is no need to rinse in HCl as the water rinses removed the water soluble nickel & copper sulfate. Depending on your feedstock, there shouldn't be other base metals to worry about.Just make sure you stirred thoroughly as each of the rinses are added. Even small amounts of sulfuric can settle to the bottom & stay among the powders, perhaps holding some base metals there. You can even feel the hot & cold bottom & top zones respectively as you 1st begin the rinses.

I do add boiling water & stir after the cool water rinses. This makes everything seem to settle quickly & if anything was stubborn about rinsing out before, that seems to get it. Make sure your vessel can handle the heat, of course.

I asked Harold about these steps, & on his advice, went to HCl-Cl with a tiny amount of sulfuric still in the powders, as he believed that this would make the lead precipitate out as lead sulfate, & he was absolutely right. Filters very easily & cleanly, with a VERY pure product. Just make sure you chill the solution, with ice if possible, &/or dilute with cold water. This will cause any residual silver to precipitate out & filter out with the lead.

 

[husker4515]

Dtectr, thanks for the information. My feedstock was 5lbs of 18k gold plated men's nugget style Geneva watches. You only wash the black powder in boiling water just once, and that is after all of the cool water washes?

 

[dtectr]

My feedstock is heavily gold plated sci-med components, brass base, flash-plate of copper, then nickel, then gold. So, I haven't had to worry about other base metals on THIS batch (I have done about 30lb so far) only copper & nickel, converted to -sulfates by the sulfuric cell) from my feed stock, & lead from the cathode is always there, even though its in relatively minute proportion, its enough to cause problems. Thus my water washes have been sufficient, use boiling water rinses as much you feel needed, it won't hurt. The rinse water color is a good indicator, as well as smell, you want to leave some sulfuric behind to address the lead.

With 18k feedstock, you will definitely have some silver to deal with, but ice/water does a good job of addressing that after dissolution with HCl-Cl & before final filtration prior to precipitation. If you seem to have copper or nickel after rinses, it would be safe to rinse with HCl if you feel you need to.

Test a small batch - my initial batches wound up at 4-5g of clean gold powder & were completely workable.

Something a little strange I do that helps me - I place the glass container on my kitchen window sill with my neighbor's white house behind it. There I watch the process intimately, its a little cool the way it follows the pattern once you learn it.

good luck & stay in touch.

 

[husker4515]

Thank you very much for all the great information. I am in the 3rd rinsing process right now, and will testing with ammonia tonight for traces of copper.
Again, thanks for the feedback.

Is it ok if I PM you if I have any addtional questions?

Thanks,
Mike

 

[dtectr]

sure thing, husker4515. I have & will receive(d) lots of help that way myself.