Assortment of gold plated ewaste i put in just muriatic acid to dissolve base metals. On day 2 have alot of black sludge why?

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I've put the Glass jar containing the gold ewaste in said picture into a crock pot and put setting at keep warm. 2 days into it and I'm seeing a lot of black sludge being formed. What is it and if there's anything I could get for further processing that be super helpful
 

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yasin1987

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I did not work with Assortment of gold plated ewaste .
But as it turns out, there is a significant amount of tin and lead that could be a problem for you.
If I were you, I would first remove the tin with sulfuric acid on Hoke's advice. (Pages 69-70-71)
Then I would strain and rinse the solution and put it in the AR.
I would also use sulfamic acid to complete the AR worked.
Sulfamic acid removes soluble nitric acid, producing sulfuric acid and precipitating lead.
Finally I filtered the solution and....
Enjoy my English :ROFLMAO:
 

MicheleM

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Still haven't gotten any replies. Not sure why but anyone's opinion would be greatly appreciated
Black (not grey) sludge could be a very fine metal powder, including copper and gold, or some insoluble salt (i.e. iron III chloride) . In my previous experiences I processed all together and then I refined the gold
 
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yasin1987

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Black (not grey) sludge could be a very fine metal powder, including copper and gold, or some insoluble salt (i.e. iron III chloride) . In my previous experiences I processed all together and then I refined the gold
If there is a little tin in your solution, you can lose a lot of gold.
 

MicheleM

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If there is a little tin in your solution, you can lose a lot of gold.
2 days in a crock pot with HCl done properly No tin will remain , except if you are processing only solders or tin balls EDIT: "if there is a little tin in your solution" , if tin is in solution, you can't loose gold, Don't you filter the solutions bearing base-metal?
 
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yasin1987

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2 days in a crock pot with HCl done properly No tin will remain , except if you are processing only solders or tin balls EDIT: "if there is a little tin in your solution" , if tin is in solution, you can't loose gold, Don't you filter the solutions bearing base-metal?
Hydrochloric acid can not dissolve tin. It can only turn it into dough.
Tin chloride drops are proof of this.
If you have or suspect tin, you should remove the tin with a mixture of water and sulfuric acid.
 

Yggdrasil

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Hydrochloric acid can not dissolve tin. It can only turn it into dough.
Tin chloride drops are proof of this.
If you have or suspect tin, you should remove the tin with a mixture of water and sulfuric acid.
You have some very absolute statements for someone asking a lot of questions.

Tin dissolves easy in HCl, even kind of easy in Nitric, but turns as you say to dough or paste as I would have called it.

So try to double check your "facts" before you offer then to someone who know less than you.

Regards Per-Ove

Edited for spelling errors.
 
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cosmetal

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Sacramento, CA USA
I did not work with Assortment of gold plated ewaste .
But as it turns out, there is a significant amount of tin and lead that could be a problem for you.
If I were you, I would first remove the tin with sulfuric acid on Hoke's advice. (Pages 69-70-71)
Then I would strain and rinse the solution and put it in the AR.
I would also use sulfamic acid to complete the AR worked.
Sulfamic acid removes soluble nitric acid, producing sulfuric acid and precipitating lead.
Finally I filtered the solution and....
Enjoy my English

Tin
Characteristics: Metallic tin is soft and malleable. It slowly dissolves in dilute nonoxidizing acids or more readily in hot concentrated HCl. It reacts with HNO3 to form metastannic acid, H2SnO3, a white substance insoluble in alkalies or acids. In neutral or only slightly acidic solutions, zinc displaces tin from its compounds, forming the metal.

Pece, Health and Happy Holidays,
James
 

Samigoli

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Dec 14, 2021
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London

Tin
Characteristics: Metallic tin is soft and malleable. It slowly dissolves in dilute nonoxidizing acids or more readily in hot concentrated HCl. It reacts with HNO3 to form metastannic acid, H2SnO3, a white substance insoluble in alkalies or acids. In neutral or only slightly acidic solutions, zinc displaces tin from its compounds, forming the metal.

Pece, Health and Happy Holidays,
James
I recently saw videos based on tin dissolving on YouTube.I just know its name is SNST 550. Does anyone know anything more?
 
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