Reducing Silver nitrate to metallic silver

[Owltech]

An easy method of producing 4 nines silver even if base metals are in solution is to reduce the solution with sodium formate as follows
1 Filter solution to remove all ppt's
2 Raise pH to 1.5 using liquid caustic
raise the temp to 130 degrees F
3 Reduce the silver by adding a solution made of saturated sodium
formate which has been reduced to a pH of 4 using formic acid (filter
any precipitate)
4 The solution will turn brown from the reduction of the silver and will
turn a bright blue (if the silver nitrate was from sterling) when the
reaction is completed.
5 Test for completeness of the reaction by sampling the solution on a
glass rod and dripping a drop into chlorinated tap water. White ppt
means more silver is present. Add more formate solution until test
yields clear drops into chlorinated tap water.

Needless to say no chlorides in the make up chemistry water
Works extremely well on sterling silver scrap digested in 50% Nitric/Distilled water. The starting pH is critical as is the pH of the formate reducing solution.

Very sleek! Can't thank you enough for sharing this method! One thing I've noticed is that if I boil the solution for about half an hour the silver clumps together, making it very easy to wash (just like the gold sponge from precipitation with oxalic acid)

 

[cuchugold]

When I open my next bottle of Talisker, hopefully soon, my first toast will be to Lou and 4metals!. Then I'll drink the rest of the bottle!. :G

 

[Palladium]

Here's a video i shot of the process 4-5 years ago! I love it and still use it from time to time.

[youtube]http://www.youtube.com/watch?v=qSzjH9cSDpw[/youtube]

 

[Owltech]

Here's a video i shot of the process 4-5 years ago! I love it and still use it from time to time.

[youtube]http://www.youtube.com/watch?v=qSzjH9cSDpw[/youtube]

I used the series as reference(as well as most of the videos you've made)! One of the first channels I subscribed to! Just didn't know it was you

Thank you!

 

[Palladium]

Thank you sir!

 

[Wiehanler]

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

 

[Yggdrasil]

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

I have never heard about adjusting the Nitrates pH.
And why would you use a formate reduction for this?

We add NaCl or HCl to drop the Silver as AgCl and then wash it thoroughly after the solid AgCl has been separated from the rest of the liquid.
After that we add NaOH to convert it to Silver Oxide and immediately after that while still hot add Sugar/Glucose/Sirup to convert the Silver Oxide to Silver Metal.

 

[Yggdrasil]

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

This looks like Silver Chloride to me!

 

[adam mizer]

An easy method of producing 4 nines silver even if base metals are in solution is to reduce the solution with sodium formate as follows
1 Filter solution to remove all ppt's
2 Raise pH to 1.5 using liquid caustic
raise the temp to 130 degrees F
3 Reduce the silver by adding a solution made of saturated sodium
formate which has been reduced to a pH of 4 using formic acid (filter
any precipitate)
4 The solution will turn brown from the reduction of the silver and will
turn a bright blue (if the silver nitrate was from sterling) when the
reaction is completed.
5 Test for completeness of the reaction by sampling the solution on a
glass rod and dripping a drop into chlorinated tap water. White ppt
means more silver is present. Add more formate solution until test
yields clear drops into chlorinated tap water.

Needless to say no chlorides in the make up chemistry water
Works extremely well on sterling silver scrap digested in 50% Nitric/Distilled water. The starting pH is critical as is the pH of the formate reducing solution.

I have never heard about adjusting the Nitrates pH.
And why would you use a formate reduction for this?

We add NaCl or HCl to drop the Silver as AgCl and then wash it thoroughly after the solid AgCl has been separated from the rest of the liquid.
After that we add NaOH to convert it to Silver Oxide and immediately after that while still hot add Sugar/Glucose/Sirup to convert the Silver Oxide to Silver Metal.

Looks like Wiehanler was following 4metals method.
@Wiehanler you did not mention if you used the formic acid in your preparation of sodium formate? Step 3 of 4metals formula.

 

[Yggdrasil]

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

Aah I see now.

But in this setting the pH and temperatures are critical I believe.
1. or 4Metals point 2: pH of 2.8-3 is not 1.5, need less NaOH.
2. The pH of 3.6 may be good enough but should be 4, too much Formic acid
3. the temperature should be 55.

Try once more and take the adjustments slow to get them right.

 

[Ronei]

To reduce silver nitrate to metallic silver powder, dissolve the silver nitrate in distilled water, then add a reducing agent like sodium borohydride or glucose. Gently heat the solution while stirring to speed up the reaction. After the reaction is complete, filter out the silver powder and let it dry. Make sure to use proper safety equipment and handle the chemicals carefully.

 

[adam mizer]

To reduce silver nitrate to metallic silver powder, dissolve the silver nitrate in distilled water, then add a reducing agent like sodium borohydride or glucose. Gently heat the solution while stirring to speed up the reaction. After the reaction is complete, filter out the silver powder and let it dry. Make sure to use proper safety equipment and handle the chemicals carefully.

Ronei,
You are missing something I think.

 

[Wiehanler]

Looks like Wiehanler was following 4metals method.
@Wiehanler you did not mention if you used the formic acid in your preparation of sodium formate? Step 3 of 4metals formula.

I did indeed use formic acid, but wasn't too accurate with the pH adjustments. I will attempt this again with more focus on the pH values as mentioned.

 

[Yggdrasil]

I did indeed use formic acid, but wasn't too accurate with the pH adjustments. I will attempt this again with more focus on the pH values as mentioned.

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

 

[Master Nater]

i gotta agree with yggdrasil. why not just precipitate with copper? much more forgiving and less testing. if need refined to a finer degree, melt metallic silver powder to shot, and run through electrolytic silver cell. comes out clean as a whistle.

 

[PeterM]

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

Sir, where you went wrong was by not adding Sucrose to the Alkaline solution, then it would have dropped finely divided silver, good luck. ***You need an organic carbon to make it work with caustic. Close but no cigar….

 

[Yggdrasil]

Sir, where you went wrong was by not adding Sucrose to the Alkaline solution, then it would have dropped finely divided silver, good luck. ***You need an organic carbon to make it work with caustic. Close but no cigar….

He used formate reduction and just needed to adjust the pH.

 

[Barstool miner]

Thanks Steve for your reply and vedio.

How then to reduce copper deluted in the solution? :?:

Read C M Hoke's Book

 

[Yggdrasil]

Read C M Hoke's Book

This post is from 2007, and anonymous means that the user is deleted from the database.
Either banned or left by himself.

 

[Ravn]

More info on silver nitrate reduction using Sodium formate can be found in the US Patent: US 6290749B1

https://patents.google.com/patent/US6290749B1/en

Preparation of ultra-pure silver metal​

Abstract​

A method for preparing ultra-pure silver from a crude silver mixture containing metallic and/or non-metallic impurities, said method comprising;dissolving the crude silver mixture in nitric acid to form a crude silver nitrate solution;adding a first selective reducing agent to the crude silver nitrate solution to precipitate a silver/contaminant matrix and form a partially purified silver nitrate solution;separating the partially purified silver nitrate solution from the precipitated silver/contaminant matrix;adding a second selective reducing agent to the partially purified silver nitrate solution to precipitate silver powder; andisolating the silver powder.