gold powder is white

[denmark1982]

why is that happen

 

[denmark1982]

an now there is some black on it

 

[FrugalRefiner]

You're going to have to provide more information before anyone can help you. What is the source of this gold? Ewaste, jewelry, ore, etc.? How did you process it? Mechanical, chemical, smelting? If you dissolved it, how did you precipitate it? SMB, copperas, cementation? You can't expect a reasonable answer unless you provide some reasonable detail.

Dave

 

[denmark1982]

there was white but now it seems to be som dark cooler

 

[FrugalRefiner]

Silver chloride.

Dave

 

[denmark1982]

thats how it looks

 

[Platdigger]

I think there should have to be some sort of standard as to asking questions here.
As per Frugal:
Like if your question is about some result you got, the poster must first explain what steps were taken, what chemicals were used, what was the feed stock and so on.
Not to single out a thread, but this just keeps happening over and over again.
It's like some big guessing game.
Perhaps a thread (like this one) just gets deleted until the poster actually provides enough information to ask the question.
Sorry for the rant.

 

[anachronism]

Silver chloride.

Dave

Yep. Dave's right you have Silver Chloride mixed with the gold. Did you filter the solution till it was crystal clear before dropping? Also as Platdigger quite rightly pointed out lets have some proper information please because until we have it, there's too much guesswork involved.

Jon

 

[denmark1982]

yes i forgot

i used 600 ML hydrochloric acid and about 35 ML nitric acid

i used about 400 grams of gold fingers so i dont know how much gold foils i have..
and the gold foil got into the aqua regia and to be sure i used i little gold nugget i got so i could get rid of the nitric acid there was left so there was no nitric acid left and then i used about 2 teaspoons of smb

and the solution gold color

 

[g_axelsson]

With a bit more details in this thread I'm guessing this is what you did...

1. you took 400 grams of fingers in a beaker, added 600 ml HCl and 35 ml HNO₃.
2. The reaction went on and dissolved both copper and gold.
3. When the reaction were finished you filtered off the solids and had a clear but dark green liquid.
4. Before or after filtering you added a button of gold to kill off any remaining nitric, i.e. denoxing it.
5. Adding two teaspoons of SMB first produced a white precipitate of copper chloride.
6. Waiting a while there were a black precipitate that settled on the bottom. This is the gold.
7. Remaining HCl dissolved the white copper chloride or you washed the precipitate in HCl. Left is your dirty black gold powder.

How close am I?

Is there any copper left on the finger boards? Hold them up to a lamp to see the shadow of internal copper layers.
How much gold dissolved from the button?
Have you tested the remaining solution with stannous to see if there is any gold left in solution?

Göran

 

[anachronism]

I think there should have to be some sort of standard as to asking questions here.
As per Frugal:
Like if your question is about some result you got, the poster must first explain what steps were taken, what chemicals were used, what was the feed stock and so on.
Not to single out a thread, but this just keeps happening over and over again.
It's like some big guessing game.
Perhaps a thread (like this one) just gets deleted until the poster actually provides enough information to ask the question.
Sorry for the rant.

Feel free to rant away you won't get any argument from me.

I've been asking the same thing for years, in fact I've made at least two threads about it. 8)

Jon