Does anyone know what's going on here?

[Xydoman]

I've been refining a lot of silver from circuit breakers, contacts from industrial motor starters and contacts from other various industrial waste I happen to pick up along the way doing my job as a boiler service tech. So I've attached pics of my quandry.. Basically, this is a solution with sulphuric acid and potassium nitrate, and distilled water I used it to dissolve the contacts. The filtered solution contained no solids, so I added table salt to turn it into AgCl. When I did, the only noticeable reaction was a miniscule amount of what could be AgCl, but it was kinda powdery (as wet powder swirling around In a solution), and not clumpy and brilliant like I'm used to seeing. So I set it aside, intending to seek advice on it the next day.

The next day my nitric acid arrived, and I had a couple of good sized batches of more contacts, so I basically forgot about this solution. It sat for a period of time.. I'd say a week or 2?? Anyways, I was rounding my lab equipment up and I came across the bowl with what now contained a brilliant deep blue color. At first I ddnt know what this was. I swirled it around and saw more white swirly stuff.. Again, appearing differently than the clumpy AgCl I know and love. Upon closer inspection, I see that it's not a white powdery substance swirling around in the beautiful blue solution, but a light silver colored substance. I also noticed blue crystals about the size of pinto beans.. A lot of them. I observed a few of these crystals and some of them have metallic silver on them... I think... It seems anyways. And lastly, the solution itself literally sparkles. It's saturated with something that gives it a distinct metallic luster, floating around the inside of it. The best way I can describe it is if you've ever looked at your girlfriends makeup containers, You might see a container with blue makeup with metallic particles added to it to give it this same sparkle, or perhaps the metallic blue paint job on a sexy sports car.. How you can almost see "into" the paint. I was wondering if it could possibly be a high quality silver. Something had to have happened to the contacts that were dissolved in this solution.. Any ideas on what it is, or how to handle it from here? I took a short video, but apparently the file is too large.. Just a 10 second video.. Less even. Anyways.. I wish I could illustrate the swirly blue metallic nature of it a bit better.

 

[orvi]

Silver sulfate is of low solubility in water (like 5g/liter). It was inevitable that it formed in the solution while dissolving the contacts. How much material was in the batch ?
I think the very big portion of silver was filtered out of the solution at the end of dissolution - as insoluble silver sulfate. Blue crystals could be copper sulfate or copper nitrate.
I could be wrong, but i will definitely check the filter paper

 

[butcher]

Copper sulfate, if I understand, and my hunch is right.

You used H2SO4 and KNO3, dissolving copper silver in a poor man's nitric acid. dissolving the copper and silver in a nitrate/sulfate solution, assuming excess H2SO4, and with the Nitrates and nitric consumed, adding NaCl to precipitate silver as a chloride salt the silver and most of the chloride could be removed or consumed basically leaving you with mostly a solution copper sulfate solution, Along with CuSO4, or AgCl, other possibles of Na2SO4, H2SO4, HCl, going further PbSO4...

Products can be different depending on how much of was used and what all was used to cause the chemical reactions...

If you have blue crystals of CuSO4 they will dissolve in water, easier to do when the crystals first form (I suppose because they hold more hydration of water in the crystal lattice), later or after drying it takes a lot more water and more heat to get the copper back into a liquid form.

Orvi, you are quick, you answered the question before I could type one word,

 

[Xydoman]

My typical batch usually contains between 50 and 75 g of silver contacts. When you said the AgCl may have been consumed.. What does that mean exactly.. I mean, I know what consumed means, but does that mean there is a situation when using poor man's nitric acid where your AgCl could go away and never Come back?

 

[butcher]

I may be using the words wrong, I often have trouble describing things.

The silver is not consumed but more like removed from the solution as soluble silver ions, basically gone from solubility in the solution as silver ions, being converted to an insoluble salt of either silver chloride or silver sulfates salts precipitating out of solubility...

Using poor man's aqua regia will not make the silver go away but it can make it much more difficult to get your silver back into elemental silver as you are making salts of your silver that can be difficult to work with or difficult to get back into metallic form.

If you make poor man's nitric it should be distilled to get a purer nitric product more suitable for working with silver, basically removing the pure nitric from the sulfate salts that will give you trouble.

Using poor man's nitric and or using a halide or a salt like sodium chloride may not make your silver disappear, but it can make it harder to recover your silver and would make everything very difficult and cause you much grief.

You need better proceedures.

 

[orvi]

My typical batch usually contains between 50 and 75 g of silver contacts. When you said the AgCl may have been consumed.. What does that mean exactly.. I mean, I know what consumed means, but does that mean there is a situation when using poor man's nitric acid where your AgCl could go away and never Come back?

maybe some misunderstanding between the lines, but your silver is still somewhere It cannot dissapear.

My first thought was, that if the silver really passed into the solution, which you were tryied to precipitate with NaCl.
If you are dissolving silver in mixture of H2SO4+KNO3, equililibrium with HNO3 and K2SO4 forms. And all 4 substances mentioned will be present in solution. This reaction have no such strong driving force, which could stop the HNO3 and K2SO4 jumping back to the H2SO4 and KNO3 completely.
Another thing is the solubility of silver sulfate. This compound have low solubility in water (ca 5g/L at 0°C, ca 8,3g/ 25°C). Hence I dont know how the solubility will be altered in the complex mixture you have created, i assume that it don´t raise sharply (just my assumption, never tried this, dont know the numbers).
My question is:

Basically, this is a solution with sulphuric acid and potassium nitrate, and distilled water I used it to dissolve the contacts. The filtered solution contained no solids, so I added table salt to turn it into AgCl. When I did, the only noticeable reaction was a miniscule amount of what could be AgCl, but it was kinda powdery (as wet powder swirling around In a solution), and not clumpy and brilliant like I'm used to seeing. So I set it aside, intending to seek advice on it the next day.

You say that after dissolution you filter the solution. Before attempted drop of AgCl with table salt. When filtering, how much of insoluble material was left in the filter ?
Silver chloride have very low solubility, ammount locked in the solution will be low, comparing to the size of the batch you did. If the contact points dissolved, silver must gone somwhere. After NaCl there should be not that much in solution, some you have precipitated as "kinda powdery" precipitate, and if my assumption is right, than the last portion was filtered directly after dissolution. This could be recovered, if you still have the first filter paper with solids. My bet is, that good portion of your silver is locked here

 

[Xydoman]

I see. I do have it and it's full of this powdery purple marerial. In fact, I have several thag look the same from different processes as I was learning. How would I recover it once it's dried?

 

[Yggdrasil]

If it is AgCl do not dry it.
It is best processed wet.
Dry it is much more complicated.