# Nanosilver?



## peter i (Mar 2, 2008)

Something funny happened today.

I was washing silver crystals from my "mini cell". First with distilled water until the wash water only showed a light milkyness on addition of chloride, then with boiling tap-water.

When I added the tap water (that contain a bit of sodium chloride around here) the water leaving the Buchner funnel became bluish or violet. The colour deepened on standing.

Do any of you guys have an idea what it is?

My best guess is that a very thin suspension of silver chloride was formed, and as the weather was beautiful, the sunlight reduced some of the silver (and for some reason, the suspension was stable).
Sticking a piece of copper in the water only gave a very light black cementation, just like the one seen from a solution almost without any silver left.
(and no ammonia was added, so it's not copper-ammonia-complex)


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## Harold_V (Mar 2, 2008)

I agree that you formed traces of silver chloride---it's very difficult to remove all traces of silver nitrate--a conclusion I came to long ago when washing my silver crystals. I agree to the point where I did exactly as you did, although I may have washed my crystal longer in that I generated only a very light trace of chloride in my final was (tap water). 

I washed until the solution coming from the wash was always free of color to insure that I left no base metals behind. 

My procedure was to place my crystals in a Buchner funnel, cover with distilled water, then allow it to drain by gravity. When it had done so, I'd pull a vacuum on the crystal until it quit dripping, then repeat. I'd do that until I had accumulated about 1½ gallons of distilled wash water. It was then used as makeup for electrolyte for the operating cell, as well as for new electrolyte. As a result, I wasn't concerned with the volume that was used, for it was not wasted. My cell ran at a temperature that was warm to touch, so there were losses to evaporation.

The first solution from the operation, after placing the crystals in the Buchner, was not reused as electrolyte. Copper was used to recover the values, then it was discarded. It was too contaminated with base metals to be recycled through the cell, shortening the life of the existing electrolyte, defeating any useful purpose by reuse. All succeeding washes were saved, however. 

My last wash, just like yours, was with tap water, straight from the tap. I used cold water to eliminate chance of transferring any dissolved base metals from the hot water tank (think sacrificial anode. Hot water tanks have them). The resulting wash water would have but a trace of chloride showing, which was allowed to settle well to collect the silver chloride for later conversion to elemental silver. 

It was common for my silver chloride to turn purple, although I do not recall having it do so immediately. I also did not work in sunlight. 

Interesting experience, Peter. 

A comment on your slick parting cell. Like you, I could see no need for a large cell, although yours, by comparison, makes mine look large. It's far better to build a small one that can be run easily than to tie up large amounts of silver in electrolyte. It's also a great way to learn the operation, even if things go wrong. You risk losing very little that way. 

Parting recycled silver pays serious benefits, especially if the silver has been previously used for inquartation. It generally contains platinum and palladium, along with traces of gold. If nothing else, the quality of silver is vastly improved by removal of traces of base metals, which are often oxidized and lead to porosity when the silver is used when casting. 

Well done.

A comment on your very nice room. Be careful to keep everything covered that you do not wish to be permanently discolored. The small droplets that have a way of getting lost will discolor your very nice tile work. 

I used old newspaper for protection, just as you've done. It was always incinerated for recovery of traces of values that got lost. 

Harold


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## peter i (Mar 3, 2008)

Harold_V said:


> The first solution from the operation, after placing the crystals in the Buchner, was not reused as electrolyte. Copper was used to recover the values, then it was discarded. Harold



That’s the exact fraction in the glass on the right. :wink: 



Harold_V said:


> A comment on your very nice room. Be careful to keep everything covered that you do not wish to be permanently discolored. The small droplets that have a way of getting lost will discolor your very nice tile work.
> Harold



It’s even worse than that!

The tiles are in the laundry room (wife’s territorie) so I ran quite a risk taking it there. Anything dirty normally happens in the workshop.
In my old house, a couple of the tables had purple splotches. The “staining power” of noble metals is terrifying!


I have a constant discussion going with myself regarding what trace amounts of metals to save. When running very small scale, the price of time quickly exceeds the value of a little silver chloride. On the other hand, there is the “noble sport of yield”…


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## Harold_V (Mar 3, 2008)

peter i said:


> That’s the exact fraction in the glass on the right.


Have you tested the solution for palladium? The color is interesting, although it could be the result of other contamination, or simply the color of the combined copper and silver. Needless to say, should they be there, given enough exposure to copper, they'll be precipitated, although I found they were last, and slow, to come down. It's obvious when they do, for the color will shift to blue, and the cement will have a darker appearance, often well discolored by the values, depending on the level of concentration. 

You likely know that the slimes will be heavy with silver. In reading how the "big boys" dealt with them, I gathered they were boiled in concentrated sulfuric acid in cast iron kettles to extract the remaining silver. While I have no experience in that regard, from reading I understand that cast iron is quite resistant to the acid so long as there is no water present. 



> The tiles are in the laundry room (wife’s territorie) so I ran quite a risk taking it there. Anything dirty normally happens in the workshop.
> In my old house, a couple of the tables had purple splotches. The “staining power” of noble metals is terrifying!


Indeed. I might suggest you took your life in your hands!  

Had I not sold my refining business, a complete cleaning and painting was in order for the three rooms that I occupied. I have posted a picture, below, which shows my silver cell in operation, along with the template used to cut the fabric for my filters. As in your case, my wife sewed them for me. The stains you see are from both gold and silver, to give folks an idea of how badly things can become discolored. 

I found that some stains could be eliminated, or drastically reduced, by washing with a solution of cyanide. You have to balance your desire to die with the desire for stain free surfaces. Strangely, I preferred life, and quit obsessing with the stains. I slowly came to terms with the idea that it was my place of work, and it would be stained, regardless of my efforts. 



> I have a constant discussion going with myself regarding what trace amounts of metals to save. When running very small scale, the price of time quickly exceeds the value of a little silver chloride. On the other hand, there is the “noble sport of yield”…


I understand the dilemma------is it worth my time, or isn't it? 

Well, in my case, I saved everything, right from the start. The papers you see under the cell were changed on a fairly regular basis, with the old ones incinerated, and the ash stored for future recovery of values, however small they may be. 

Assuming you pursue this interest with vigor, it's hard to say how much you may put away as a savings for the future. It worked very well for me, but then I refined for many years, on a constant basis. 

Silver chloride can be stored in a glass jar with a lid, until you have a substantial amount. As long as you keep it wet, it's very easy to process at your convenience. I processed mine only when I accumulated no less than a quart-----which represents a reasonable amount of value, particularly on today's market. 

Hard to advise others in this area. Some people think nothing of tossing small amounts of value. Personally, I'm known to pick up a penny, or an aluminum can. You understand, of course, that I am retired and live on limited funds. It's likely different for folks that have a decent income and are strapped for time. 

Harold


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## peter i (Mar 3, 2008)

I hate tossing values (unless tossing clearly cost me more than recovering it).

My lab-coat is badly stained from gold and silver, maybe I should refine it once it’s worn out?
:wink:


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## Harold_V (Mar 4, 2008)

peter i said:


> I hate tossing values (unless tossing clearly cost me more than recovering it).
> 
> My lab-coat is badly stained from gold and silver, maybe I should refine it once it’s worn out?
> :wink:



I sure would if conditions were reversed. I used to incinerate my old gloves for that very reason. NOTHING that contacted precious metals was discarded in my operation----it was all recycled. Smartest thing I ever did. 

As Irons says, everything but the squeal!

Harold


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## austexjwlry (Mar 4, 2008)

peter i,

Do you have a high iron content in your tap water? Its odd that you didn't get a change of color until you added the tap water. You could test this by dissolving a tiny bit of iron into solution and perhaps a tiny bit of copper also hoping to duplicate the color by setting in sunlight to test the reaction. Perhaps place a piece of copper in this solution to see if you get a simular black material cemented out of solution?

Both silver sulphate and silver nitrate darken on exposure to sunlight but shouldn't the beaker containing the green solution with probably the same approx. amount of silver in it have darkened also if sunlight alone caused this change of color?

Wayne


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## peter i (Mar 5, 2008)

I wonder too!

And I'll do what I can to repeat it.

(And my water is first class well water, relatively hard from calcium and magnesium, a little chloride and nothing else)


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## austexjwlry (Mar 7, 2008)

Harold,

I folded up a small section of newspaper and stuffed it under my deplating cell to level it in my tuppaware container "fume hood". I didn't notice any smoke or flame but the sulphuric drops spilled one at a time in the container running down the sides to the bottom sure did burn it! The spot in the tuppaware where the newspaper was sitting is slightly discolored but not actually burnt.

Have you or anyone else ever seen or heard of an actual fire from this reaction?

Thanks again for all your help!

Wayne


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## Lou (Mar 7, 2008)

Not from concentrated sulfuric which just dehydrates, but when it is a stronger (oleum, a fuming sulfuric acid), there can be fires.


In general, keep acids that dehydrate and oxidize away from organic materials.


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