The powder was cleaned with hydrochloric acid, washed and redissolved in aqua regia. I did not cancel the nitric acid, but I added sodium hydroxide to adjust the pH. At the same moment, a red-brown precipitate began to settle, and there was more and more of it. What could that metal be?
The powder of which metal is reduced in the presence of HNO3
- Thread starter Lola
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Metal powders are usually oxidized, as that is the very nature of the classic dissolution process - ripping off the electrons from the zero-valent metal.
Define what are you working with - from first sight I think about re-refining gold, but as it isn´t explicitly said, I can only guess. Exact feed and exact steps what you did. Otherwise we can only guess and it is then waste of time for all of us.
What was the point of raising pH ?
Upon raising pH, iron compounds usually come out first as voluminous yellow-brown rusty ppt. But it can be variety of things.
Define what are you working with - from first sight I think about re-refining gold, but as it isn´t explicitly said, I can only guess. Exact feed and exact steps what you did. Otherwise we can only guess and it is then waste of time for all of us.
What was the point of raising pH ?
Upon raising pH, iron compounds usually come out first as voluminous yellow-brown rusty ppt. But it can be variety of things.
Is this still the same thing as before?
Which powder and why Sodium Hydroxide?
If you added NaOH I'd guess it is not a metal but some kind of Hydroxide for instance Iron.
More info is needed.
I added NaOh to adjust the pH, but the powder immediately started to settle and didn't dissolve anymore. Can ferric hydroxide be precipitated in the presence of HNO3
Since the powder was first washed in hydrochloric acid, shouldn't the iron have dissolved and the powder was free from the presence of iron?
Is this the same powder you have been working with?
Why did you want to adjust the pH
You do not reduce the acidity of AR before dropping gold. You denox it, neutralizing the nitric (nox), while keeping the HCl acidic. With out the acidity of the HCl, SMB will not reduce the gold back to its metallic state. Now it would be helpful to answer Orvi and Yaggdrasils question so they can further help you.
Hvala
other
for gold reduction
No need to adjust pH for the unless it is too high.
If you are unsure, add a bit of HCl.
So where did your powder come from?
If you are unsure, add a bit of HCl.
So where did your powder come from?
from the water
That will not work.
Read my reply in the other thread.
There simply are not enough Gold in the water.
I challenge you to produce a repeatable assay showing other ways.
