Hno3 neutralized

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Gokhan09

Member
Joined
Nov 21, 2021
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12
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Türkiye
Selamlar. 3 aydır hurda ürünlerinden altını ayırıyorum. Ben genellikle işleyeceğim malzemeye göre 100ml hcl 5ml hno3 kullanıyorum ve hno3'ü üre ile nötralize ediyorum. Bazen dibe ulaşamıyorum. Bu konu hakkında herhangi bir öneriniz var mı?
 
Even though I deactivate the royal water, the pH of the solution becomes 1. My question is this. Can I precipitate gold when Ph is 1?
 
I'll assume that when you say you "deactivate" the aqua regia, you mean that you deNOx it, meaning that you eliminate any excess nitric acid. The solution should still be acidic, as there should still be some HCl left.

Although some people recommend raising the pH a bit, having the pH at 1 should not be a problem.

Dave
 
First of all, thank you very much. I would be very grateful if you could let me know what I need to do to increase the pH.
 
You dont have to raise your PH. Its related with base metals in solution. If you have a gold rich Aqua Regia you can drop larger chunks. If you have a emerald green aqua regia its gonna be like dust at the bottom.

Konya'dan selamlar.
 
Never tried it, but i think at pH 3 or 4 there will not be enough free HCL left for the SMB to react with.
And you could be pushing out base metal hydroxides, polluting your gold.
Chunkier precipitated gold will be harder to wash. It's better to have a powder that settles fast.
 
In my opinion chunks are received with (COOH)2 oxalic acid precipitant, hot. As organic acid it may have a higher pH around 2. So what gives chunks may not be the higher pH, but also temperature and kind of precipitant or all
 
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I'll assume that when you say you "deactivate" the aqua regia, you mean that you deNOx it, meaning that you eliminate any excess nitric acid. The solution should still be acidic, as there should still be some HCl left.

Although some people recommend raising the pH a bit, having the pH at 1 should not be a problem.

Dave
If ph is lower will the gold be finer as it precipitates and larger powder with higher pH? I've refined only a small amount twice now. Basically after dessolved in aqua regia I filter then only water added is basically what I've used to rinse color through filter. Very little diluting of the acids. Is their an ideal ratio going from stronger acid to digest the gold and solution to drop the gold? Also using HCl nitric acids then dropping with smb. Denoxing hasn't been an issue yet as very little nitric gets job done
 
I never measure pH before dropping. I guess its at 1 because of enough free HCL.
Dilute solutions give fine precipitate. Heat with H2SO4 to make it fall out. Concentrated solutions give heavier precipitate.
Dilute and chill by adding ice cubes before filtering, pushing out AgCl.
 
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