pH of the Silver nitrate solution for cementing with copper.

[Amol Gupta]

I have dissolved some pure silver using nitric acid, I started of with a solution(approx 5ml) of nitric acid and distilled water with a pH of 1, after dissolving some silver approx(1.25-1.5g) with some silver still at the bottom the pH has dropped to close to 5.
I was wondering what should be the pH of the solution before I start cementing the silver using copper.

 

[Yggdrasil]

I have dissolved some pure silver using nitric acid, I started of with a solution(approx 5ml) of nitric acid and distilled water with a pH of 1, after dissolving some silver approx(1.25-1.5g) with some silver still at the bottom the pH has dropped to close to 5.
I was wondering what should be the pH of the solution before I start cementing the silver using copper.

Welcome.
That do not make much sense since 5ml of Nitric should dissolve more than 5 gram of pure Silver.
Are you sure it is not Sterling or other Silver alloys?

The pH should also still be in the lower than 1 range.

Why do you dissolve pure Silver for then cementing it out later?

Can you describe step by step what you have done?



Anyway here is for your studies:

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798
2. Then read the safety section of the forum: https://goldrefiningforum.com/forums/safety.47/
3. And then read about "Dealing with waste" in the forum: https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Suggested reading:
https://goldrefiningforum.com/forums/the-library.101/
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
https://goldrefiningforum.com/threa...le-read-this-before-you-post-about-ore.33333/


Forum rules is here.
https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/

 

[Amol Gupta]

So this is my first experience of dissolving silver in nitric acid, the solution including distilled water is close to 5ml(I did read some previous post that suggested 0.7-1.2ml of 70% nitric acid will dissolve one gram of silver).
And yes I have pure silver coin with xrf readings suggesting 99.7% silver with the rest(0.3%) being copper.
I am dissolving and recovering pure silver just to get a hang of things and see what can be the expected losses in the process.

I have tested the pH of the solution before and after the addition silver to my solution of distilled water and nitric acid .

I am fairly confident I would have close to 1.5-2ml 70% nitric acid and the rest 3-3.5ml being distilled water.

What I am looking for is the expected pH of the solution before I add copper to cement the silver.

 

[Yggdrasil]

So this is my first experience of dissolving silver in nitric acid, the solution including distilled water is close to 5ml(I did read some previous post that suggested 0.7-1.2ml of 70% nitric acid will dissolve one gram of silver).
And yes I have pure silver coin with xrf readings suggesting 99.7% silver with the rest(0.3%) being copper.
I am dissolving and recovering pure silver just to get a hang of things and see what can be the expected losses in the process.

I have tested the pH of the solution before and after the addition silver to my solution of distilled water and nitric acid .

I am fairly confident I would have close to 1.5-2ml 70% nitric acid and the rest 3-3.5ml being distilled water.

What I am looking for is the expected pH of the solution before I add copper to cement the silver.

It just need to be acidic, but preferably not higher than 4
Please read the material I gave you links to.

Did you heat the solution during dissolving?

 

[Amol Gupta]

Yes I did heat the solution during dissolving, I am conducting the experiment is a test tube and I did heat up the solution for dissolving silver.

I was wondering approximately how much time would it take to cement out the silver and if heating would be required to cement the silver,....?

 

[Amol Gupta]

@Yggdrasil I'd like to thank you for such a quick response.

 

[Yggdrasil]

Yes I did heat the solution during dissolving, I am conducting the experiment is a test tube and I did heat up the solution for dissolving silver.

I was wondering approximately how much time would it take to cement out the silver and if heating would be required to cement the silver,....?

No need for heating during cementing, it will be a bit faster though.
Still I recommend you to wait until you have read the book from Hoke in the links.

 

[Amol Gupta]

I have gone through the book, it was quite a task reading the 350 page book but I skipped the last few chapters to be honest dealing with laws and regulations, dealers etc.

 

[Yggdrasil]

I have gone through the book, it was quite a task reading the 350 page book but I skipped the last few chapters to be honest dealing with laws and regulations, dealers etc.

That part is not very important, since the book is from around 1940.
Much stricter today.
Safety and dealing with waste is however.

 

[Yggdrasil]

Yes I did heat the solution during dissolving, I am conducting the experiment is a test tube and I did heat up the solution for dissolving silver.

I was wondering approximately how much time would it take to cement out the silver and if heating would be required to cement the silver,....?

You started with pure Silver and now you are going to cement it and then you will probably contaminate your Silver with additional Copper.
Better do a Chloride drop and conversion.

 

[FrugalRefiner]

You started with pure Silver and now you are going to cement it and then you will probably contaminate your Silver with additional Copper.
Better do a Chloride drop and conversion.

I wouldn't bother with that for 1.25 to 1.5 grams. This sounds like a good acquaintance experiment to me. Cement it out, then save it to reprocess later when you feel comfortable working with greater quantities and/or are setting up a silver cell.

Dave

 

[Amol Gupta]

You started with pure Silver and now you are going to cement it and then you will probably contaminate your Silver with additional Copper.
Better do a Chloride drop and conversion.

Chloride is not something I want to deal with as the first step, I feel it's better to get a hang of things before taking up such complex tasks.

 

[Amol Gupta]

I wouldn't bother with that for 1.25 to 1.5 grams. This sounds like a good acquaintance experiment to me. Cement it out, then save it to reprocess later when you feel comfortable working with greater quantities and/or are setting up a silver cell.

Dave

As a second step I am planning to refine later with lye and sugar but I'd rather be safe than sorry.

 

[Yggdrasil]

As a second step I am planning to refine later with lye and sugar but I'd rather be safe than sorry.

Lye and Sugar is for Chloride conversion.

 

[Amol Gupta]

Lye and Sugar is for Chloride conversion.

Yes if my knowledge serves me correct re-dissolving the cemented silver in nitric acid and sedimenting it as silver chloride seems to be a trivial task, refining the silver-chloride with lye and sugar is what seems to be complicated.

 

[Shark]

refining the silver-chloride with lye and sugar is what seems to be complicated.

That is why we have the iron and sulfuric method. For me it is simpler and less messy.

 

[anachronism]

That is why we have the iron and sulfuric method. For me it is simpler and less messy.

Agreed, and zinc is even better.

 

[Yggdrasil]

Agreed, and zinc is even better.

So you can use Zinc and Sulfuric?

 

[Shark]

Agreed, and zinc is even better.

Never ran across the zinc method. Any details for it.

 

[Amol Gupta]

Thank you guys I was able to cement out the silver.
My first effort seems to be fairly decent, thanks...