White precipitate

Help Support Gold Refining Forum:

sayf

Well-known member
Joined
Sep 1, 2020
Messages
84
Hello every one, i decided to recover gold from old T.V ic's i collected one kg of those ic's and trimmed their pins then burned them, crushed them and separated the hard stuffs from the powdered stuffs using a sieve
After that i used my strong magnet on the powder and removed the magnetic stuffs inside them and did the same on the hard stuffs so now i have 3 categories
1-non magnetic powder
2-non magnetic hard wires
3-magnetic powder and hard wires

i worked on the non magnetic powder first
i directly boured them in AR and filtered the solution and got nice green colored solution after that i tested with stannous chloride and got a positive purple color then i eliminated the nitric acid using sulfamic and tried precipitating using iron sulfate and nothing happened, i thought that my iron sulfate maybe became outdated so i used SMB to precipitate the gold, after adding SMB directly a white milky cloud formed, i stirred the solution and that cloud settled down in few minutes
am really wondering what was that white cloud 🤔?
i excluded the silver because it should appear earlier not after adding SMB so is it tin?
i also excluded tin and lead because i trimmed the pins of the ic's, i cant find any explanation my friends
 

sayf

Well-known member
Joined
Sep 1, 2020
Messages
84
This is the color of the precipitate
 

Attachments

  • IMG_20210118_061150.jpg
    IMG_20210118_061150.jpg
    2.8 MB · Views: 188

g_axelsson

Administrator
Staff member
Administrator
Moderator
Joined
Nov 17, 2007
Messages
5,499
Location
Sweden
I don't think it's lead. The sulfamic acid should have taken care of that in a previous step.

I don't think it is silver either. Silver chloride might dissolve in strong chloride solution but not that much.

I do think it's copper I chloride, CuCl. SMB can reduce CuCl2 to CuCl when there isn't a lot of acid left. It will also precipitate the CuCl as a white salt. Low acidity is also a problem when you use SMB, it needs the acid to release SO2 that reduces the gold.

What does a stannous test show at the moment?

Pour off the liquid in a separate container and add a bit of HCl to see if the salt dissolves. If it does then add a bit of HCl to the liquid too, it might precipitate the gold.

You said that the stannous test showed purple. Stannous is really sensitive so a purple stain can still be just a little bit of gold, maybe too little to show when it's mixed in with the white precipitate.

Göran
 

Rotz

Well-known member
Joined
Sep 2, 2020
Messages
57
Hey

Could it be over dose smb and copperas? Stannous test will show your next step.


Sent from my iPhone using Tapatalk
 

sayf

Well-known member
Joined
Sep 1, 2020
Messages
84
g_axelsson said:
I don't think it's lead. The sulfamic acid should have taken care of that in a previous step.

I don't think it is silver either. Silver chloride might dissolve in strong chloride solution but not that much.

I do think it's copper I chloride, CuCl. SMB can reduce CuCl2 to CuCl when there isn't a lot of acid left. It will also precipitate the CuCl as a white salt. Low acidity is also a problem when you use SMB, it needs the acid to release SO2 that reduces the gold.

What does a stannous test show at the moment?

Pour off the liquid in a separate container and add a bit of HCl to see if the salt dissolves. If it does then add a bit of HCl to the liquid too, it might precipitate the gold.

You said that the stannous test showed purple. Stannous is really sensitive so a purple stain can still be just a little bit of gold, maybe too little to show when it's mixed in with the white precipitate.

Göran
Hey goran u r rock sir
I believe what you said is right the white precipitate is gone and a brown one is left behind
Ill add a screen shot for the precipitate and the first stannoys test i did
 

Attachments

  • Screenshot_20210119_075803_com.huawei.himovie.overseas.jpg
    Screenshot_20210119_075803_com.huawei.himovie.overseas.jpg
    753.1 KB · Views: 140
  • Screenshot_20210119_075525_com.huawei.himovie.overseas.jpg
    Screenshot_20210119_075525_com.huawei.himovie.overseas.jpg
    321.5 KB · Views: 140

yasin1987

Active member
Joined
Dec 3, 2020
Messages
42
Dear friend
Tin chloride test should be performed after removal of excess nitric acid.

HNO3 + H3NSO3 → H2SO4 + N2O + H2O
 

sayf

Well-known member
Joined
Sep 1, 2020
Messages
84
yasin1987 said:
Dear friend
Tin chloride test should be performed after removal of excess nitric acid.

HNO3 + H3NSO3 → H2SO4 + N2O + H2O
Why is that sir ?
can you explain please
 

Rotz

Well-known member
Joined
Sep 2, 2020
Messages
57
yasin1987 said:
Dear friend
Tin chloride test should be performed after removal of excess nitric acid.

HNO3 + H3NSO3 → H2SO4 + N2O + H2O
When we check the Ar solution. It have excess nitric but ıt is working.


Sent from my iPhone using Tapatalk
 

yasin1987

Active member
Joined
Dec 3, 2020
Messages
42
sayf said:
yasin1987 said:
Dear friend
Tin chloride test should be performed after removal of excess nitric acid.

HNO3 + H3NSO3 → H2SO4 + N2O + H2O
Why is that sir ?
can you explain please

Adding sulfamic acid to nitric acid produces sulfuric acid.
This is good in two ways.
Nitric acid is easil removed.
And sulfuric acid separates lead from the solution.
 

Latest posts

Top