Needle like crystals in silver nitrate

Hello everyone been a while since I have done any refining on here. What I have started with is about 1Kg of sterling material, as far as I have been told from old jewelry. I have melted and poured into cornflakes put in 500ml water and about 200 ml nitric acid, heated and when it cooled I got these crystals. I am trying to determine what they may be, I am thinking maybe lead but I am not sure. They dissolve with very little heat and I am sure they can be filtered easily just any thoughts would be helpful. The solution is actually more green than blue.
thanks

I agree, it sounds and looks like lead nitrate.

Dave

Hello everyone been a while since I have done any refining on here. What I have started with is about 1Kg of sterling material, as far as I have been told from old jewelry. I have melted and poured into cornflakes put in 500ml water and about 200 ml nitric acid, heated and when it cooled I got these crystals. I am trying to determine what they may be, I am thinking maybe lead but I am not sure. They dissolve with very little heat and I am sure they can be filtered easily just any thoughts would be helpful. The solution is actually more green than blue.

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According to my calculations, it would take close to 1490ml of 70% nitric acid plus 1490ml of distilled water to dissolve 1000g of sterling silver.

If the sterling is 90% and it takes 1.2ml of nitric to dissolve a gram of silver and 4.1g per gram of copper, it will take 1000 x .9 x 1.2 = 1,080ml for the silver and 1000 x .1 x 4.1 = 410ml for the copper - total of 1490ml of 70% nitric.

I assume that everything is not dissolved. If it did, you either made a mistake on the amounts you used or it wasn't sterling

No your math is right on, not all of it is dissolved by a long shot, what I am curious about is how to clean it up, what I was thinking was to just carry on and then when everything is gone but what will not dissolve, filter it off when it is cold and separate the crystals off , drop with copper I am going to guess there should be some amount of lead there the the silver cell should clean that up. My first batch of silver I did not have these crystals but also I had a much poorer system (or so I thought) and ended up with about 8L of solution so I might have had some lead but had a lot more solution to hide in. This round trying to keep it concentrated, my nitric is about 63% still doing the 50/50 distilled water going 500ml each at a time then pour it off.
Thanks

Cold saturated silver nitrate solutions will form crystals in my experience, dissolve all your material and add more water and see if those crystals disappear.

nickvc said:

Cold saturated silver nitrate solutions will form crystals in my experience, dissolve all your material and add more water and see if those crystals disappear.

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I agree with Dave - they look more like lead nitrate crystals then silver nitrate crystals --- silver nitrate crystals are more cubic

Kurt

I go with lead nitrate also.

Silver nitrate crystals

Use distilled water to dissolve

More crystal fun! This time the saturated silver has cemented out on the undigested materials to look like flat fern patterns.

I found it sort of just hanging around. :mrgreen:

Look!!! It brought a friend.

Where are the candles to go on top?

That is crazy looking, I no where near that level of material sadly, do have some in a cell making upside down trees, slowly

Experiences like this makes studying and holding the material harder :lol: ... sweet!

Thank you to all the moderators and active members for this wonderful resource.

I have been studying this forum and Hoke for several months, and after finally building my fume hood I got to work.

I inquarted some carat scrap and upon digesting the 6k gold cornflakes with 50.50 nitric acid solution I discovered some strange crystals.

At first it appeared to be a gel, but it also looked like clear little sheets. It almost looked like mica and was very shiny and beautiful when swirled. Even though it still acted like a gel when decanted.

It settled quickly and dissolved completely when washed with warm DI water.

After several cycles through nitric and DI water washes, I have nice clean light orange brown colored gold and think I am ready for the AR stage

The only other thing to add is that I used quite an excess of Borax during the melt, and had some sand like slag that made its way into the inquarted gold cornflakes.

My questions are.....

1. do you think these are indeed lead nitrate crystals? Or somehow related to the borax? Or something else entirely?

2. If lead nitrate, where could the lead have come from? This was all Italian gold, mostly 18k (so I was told). And the silver was 1 oz rounds I bought from a reputable coin and jewelry store.

2. Having done a meticulous nitric digestion of the inquarted gold, will I further need to worry about lead in the AR stage of processing? (Adding a few drops of sulfuric acid perhaps?)

3. When recovering the silver, will washing the silver chloride in boiling water be enough to remove all of the lead?

Thank you so much for your time, Vinny

Vinny PaisAuno said:

Thank you to all the moderators and active members for this wonderful resource.

I have been studying this forum and Hoke for several months, and after finally building my fume hood I got to work.

I inquarted some carat scrap and upon digesting the 6k gold cornflakes with 50.50 nitric acid solution I discovered some strange crystals.

At first it appeared to be a gel, but it also looked like clear little sheets. It almost looked like mica and was very shiny and beautiful when swirled. Even though it still acted like a gel when decanted.

It settled quickly and dissolved completely when washed with warm DI water.

After several cycles through nitric and DI water washes, I have nice clean light orange brown colored gold and think I am ready for the AR stage

The only other thing to add is that I used quite an excess of Borax during the melt, and had some sand like slag that made its way into the inquarted gold cornflakes.

My questions are.....

1. do you think these are indeed lead nitrate crystals? Or somehow related to the borax? Or something else entirely?

2. If lead nitrate, where could the lead have come from? This was all Italian gold, mostly 18k (so I was told). And the silver was 1 oz rounds I bought from a reputable coin and jewelry store.

2. Having done a meticulous nitric digestion of the inquarted gold, will I further need to worry about lead in the AR stage of processing? (Adding a few drops of sulfuric acid perhaps?)

3. When recovering the silver, will washing the silver chloride in boiling water be enough to remove all of the lead?

Thank you so much for your time, Vinny

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Welcome to us.
Reading Hokes book will bring you up to speed relatively fast

Regarding your inquart, I have a few questions.
Mostly Italian 18k, what was the rest?
How did you determine the amount of Silver to use?
If you did not introduce Lead there should not be Lead in there.
To make sure add 2-3 drops of Sulfuric, if it is Lead it will drop as Lead Sulfate immediately.
Why did you use Borax? If your dish is glazed with Borax you don't need more.

After adding Sulfuric no need to worry about Lead in your Gold, filter out all solids and put it in your solid waste.

Which brings us to the next step of your "education".

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: Screen Readable Copy of Hoke's Book
2. Then read the safety section of the forum: Safety
3. And then read about "Dealing with waste" in the forum: Dealing with Waste

Suggested reading: The Library

Forum rules : https://goldrefiningforum.com/threads/board-policy-this-should-be-read-by-everyone.4646/

Thank you for your reply

Yggdrasil said:

Regarding your inquart, I have a few questions.
Mostly Italian 18k, what was the rest?
How did you determine the amount of Silver to use?

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The other item was a 14k ring. All items were hallmarked, and I confirmed with acid test.

I added 213.4 gms of silver to 80.4 gms carat scrap.

My math as follows
There were 71.3gm of 18k (53.5 of Au, 18gm of base metal) and 9.1gm of 14k (5.3gm Au, 3.8gm base metal). This is a total of about 58.8gm Au and 21.8 of base metal. Gold / base metal (X) needs to equal .25. so 58.8gm Au / x=.25. ---> x=.25/58.8 = 235 2 Since we already have 21.8gm base we subtract that from 235.2 to get needed amount of silver which is 213.4 gms. Checking our work. 58.8 gm Au / (21.8+213.4)=.25

Yggdrasil said:

After adding Sulfuric no need to worry about Lead in your Gold, filter out all solids and put it in your solid waste.

Click to expand...

Just to clarify, we add 2 or 3 drops of sulfuric after the gold has fully dissolved in AR is that correct?

Thanks again for your help!

Vinny PaisAuno said:

Thank you for your reply

The other item was a 14k ring. All items were hallmarked, and I confirmed with acid test.

I added 213.4 gms of silver to 80.4 gms carat scrap.

My math as follows
There were 71.3gm of 18k (53.5 of Au, 18gm of base metal) and 9.1gm of 14k (5.3gm Au, 3.8gm base metal). This is a total of about 58.8gm Au and 21.8 of base metal. Gold / base metal (X) needs to equal .25. so 58.8gm Au / x=.25. ---> x=.25/58.8 = 235 2 Since we already have 21.8gm base we subtract that from 235.2 to get needed amount of silver which is 213.4 gms. Checking our work. 58.8 gm Au / (21.8+213.4)=.25


Just to clarify, we add 2 or 3 drops of sulfuric after the gold has fully dissolved in AR is that correct?

Thanks again for your help!

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Yes or even better in the Nitric after the parting is finished.
And then in the AR for safe measures

Okay excellent thank you.

Unfortunately there is definitely lead. See video. It appears that it will be a factor in silver recovery.

I like the prospect of adding sulfuric acid to the nitrate solution because of the very obvious precipitate which can easily be filtered. Seems like the best way.

However I could also add HCl and convert lead and silver nitrates to chlorides and wash with boiling water. But how would I know if I got all the lead sulfate dissolved?

Does anyone have a strong opinion about which method is best regarding purity? I'm definitely leaning towards sulfuric acid method.

Assuming I go with sulfuric method, after adding sulfuric drop wise I should mix it right? And stop adding drops when no more precipitate forms?

Otherwise, I think the inquarted gold turned out nicely, and as a bonus the 2 tiny diamonds from my grandfather's wedding band made it through unscathed. I cannot believe that!

Thanks again for your help! Vinny