Reducing Silver nitrate to metallic silver

[Martijn]

Good day,
I recently attempted the formate process as described by @4metals.

Encountered a few issues and wish to ask for some guidance.
1) upon adjusting my silver nitrate pH with caustic soda, it never turned brown. There were some precipitates, and the pH settled around 2.8-3, but I didn't get to a brown solution. It stayed pretty much blue.
2) I made up a sodium formate solution and got its pH to 3.6.
3) heated the pH adjusted silver nitrate to about 48-50ºC and added sodium formate
4) very fine precipitate started forming, but as the precipitate settled, I observed another layer (refer to attached photo)

Can someone please give guidance as to what this second layer possibly can be?

My next anticipated step would be to filter, wash properly until effluent is clean, dry and then to try and melt.

Would appreciate any thoughts.

Wiehan

Did anyone recommend a silver nitrate cell yet? depending on how polluted you siler nitrate is, it is a very high purity output process.

 

[Wiehanler]

Why don't you use one of the other more forgiving methods?

Hi Yggdrasil,

I work in a refining plant and we generate quite a volume of silver nitrate in a month. Precipitating AgCl with salt (NaCl) and then adding caustic and dextrose to convert to metallic silver is a well-known process to us.
The formate process just intrigued me as it seems a quicker (and probably marginally more cost effective) process to convert large volumes of AgNO3 to metallic silver.
I also understood that the formate process tends to yield relatively high purity.

Irrespective of how we process the silver nitrate, all the metallic silver we obtain are processed through an electrolytic cell to a final product of 99,99% purity.

 

[Yggdrasil]

Hi Yggdrasil,

I work in a refining plant and we generate quite a volume of silver nitrate in a month. Precipitating AgCl with salt (NaCl) and then adding caustic and dextrose to convert to metallic silver is a well-known process to us.
The formate process just intrigued me as it seems a quicker (and probably marginally more cost effective) process to convert large volumes of AgNO3 to metallic silver.
I also understood that the formate process tends to yield relatively high purity.

Irrespective of how we process the silver nitrate, all the metallic silver we obtain are processed through an electrolytic cell to a final product of 99,99% purity.

The least waste is probably generated by using the Sulfuric/Iron or HCl/(Aluminum or Zinc) method.

 

[anachronism]

The least waste is probably generated by using the Sulfuric/Iron or HCl/(Aluminum or Zinc) method.

The ion echange is also Sulphuric/Zinc Ygg, the HCl is used to take out the excess Zinc (if any) after conversion.