# Silver chloride conversion with UV light



## mls26cwru (Aug 16, 2017)

I was thinking the other day when i was contemplating converting the silver chloride i have stored up....

Would it be possible to convert silver chloride by stirring it while exposing it to UV light? Maybe in a sodium hydroxide solution? I'm not even sure if the chemistry would work, but isn't that the principle the old photographic plates were based on? 

If it could be done in neutral water, then there wouldn't be any need for waste treatment like the sugar/let method... just thinking out loud... Any thoughts?


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## Lino1406 (Aug 16, 2017)

1. When silver chloride particle is exposed to light, it becomes covered with silver which prevents the continuation of the process.
2. Silver chloride + caustic soda = silver oxide


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## butcher (Aug 17, 2017)

As lino pointed out, only the outside of the silver chloride gets converted by light, the inside is still silver chloride. 

silver chloride + H2SO4 + iron (skillet), good stirring and just a little heat = silver + iron II sulfate (copperas or green vitriol) by product.


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## mls26cwru (Aug 17, 2017)

I was wondering if the particle size of the AgCl would be too large, or maybe it would be diffuse enough to allow UV light to penetrate, or since silver is transmissive in the UV part of the spectrum, that maybe it would allow enough penetration that it would work... 

I was basically thinking of putting a beaker on a stir plate under a black light and let it run for a few hours. I was just figuring I would check to see if anyone else had tried it or something similar with any success.

Thanks for your thoughts guys!


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## butcher (Aug 17, 2017)

I suspect as Lino very well pointed out, the salt gets a passivated coating, stirring and mechanical action of salts abrasive action on each other (in the constant stirring action) may help, but some how I do not think it would be a reliable conversion method beyond a good and interesting experiment.


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## mls26cwru (Aug 17, 2017)

I really like how nifty the sulfuric conversion works giving a usable byproduct. If I had sulfuric, I would try that... although I probably shouldn't use my No.12 Griszwold for that!

Just out of curiosity, would the sulfuric need to be diluted at all for that reaction? Concentrated Sulfuric is some nasty stuff that I try to avoid.


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## Lino1406 (Aug 17, 2017)

Silver is not transmissive to UV. However, nano-scale may work but is it worthwhile?


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## Topher_osAUrus (Aug 17, 2017)

mls26cwru said:


> I really like how nifty the sulfuric conversion works giving a usable byproduct. If I had sulfuric, I would try that... although I probably shouldn't use my No.12 Griszwold for that!
> 
> Just out of curiosity, would the sulfuric need to be diluted at all for that reaction? Concentrated Sulfuric is some nasty stuff that I try to avoid.



10% to 20% sulfuric is plenty
I take my filtrate, and evaporate it down to copperas crystals.
Sometimes i add a bit more iron while evaporating, to make sure all the sulfuric is used up from the AgCl conversion.
Usually it is.

It helps to save "waste" by reusing as much stuff as humanly possible


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## mls26cwru (Aug 17, 2017)

Lino1406 said:


> Silver is not transmissive to UV. However, nano-scale may work but is it worthwhile?



yeah, i was looking at some transmission/reflectance curves on some charts we have here at work, but it seams that much past about 100-150nm in film thickness, the transmission is reduced drastically. So it would seem that it would work nano-scale, but the practicality in a refining situation... not so much. 

Oh well, it was just a thought


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## FrugalRefiner (Aug 17, 2017)

For the sake of discussion and the experiment, I wonder what would happen if you put the silver chloride in a mild nitric leach and subjected it to light? The silver chloride wouldn't be affected by the nitric, but as it converted to silver, the nitric should dissolve it. But with those pesky chloride ions being freed up, it might just become silver chloride again in an endless cycle. :| Just thinking out loud.

I like the sulfuric and iron method myself.

Dave


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## bigpagoda (Aug 19, 2017)

> For the sake of discussion and the experiment, I wonder what would happen if you put the silver chloride in a mild nitric leach and subjected it to light?


 I have always wondered about using UV light to degrade nitric for denoxing purposes? I have seen where it is produced in fume hoods that have the lights turned off or covered to prevent it from this degradation. Anyone ever heard of this?


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## butcher (Aug 19, 2017)

Nitric acid does decompose in light to NO2,one of the reasons it is stored in amber or dark colored bottles, or dark places...

Light would not be an effective way to denox a gold chloride solution,(especially on with any excess of HNO3, or any base metals. just my humble opinion, unless your willing to sit there for a very long time 


Just look how long it can take to rid excess HNO3 and NOx, gases in a fairly pure gold chloride solution, then if the gold chloride solution has much other metals involved like copper which will form nitrates, say for example copper nitrate in solution, we have to drive it under heat to evaporate it to a thick solution, then upon adding an acid, normally HCl, the metal salt Copper nitrate will form HNO3 again and NOx gases, and then we may have to repeat this several times (normally 2-3 times) depending on excess nitric used and base metals involved, and if we did not evaporate down far enough, even after that we may have to add sulfamic acid... 
And all the while we can be doing this with the bright sunlight glowing into the vessel.
Note the sunlight or other light can decompose nitric acid to Nox gases... 

Using only the amount of nitric acid you need (in small additions of nitric acid) (with the excess of calculated amount of HCl, for the weight of gold in solution). Not dissolving all of the fairly pure gold, making nitric acid, the limited reactant in our chemical reaction. 
Then after the initial reaction is finished, using heat to dissolve more of that gold, as you are concentrating the solution, only adding nitric drop-wise to the fairly concentrated chloride solution, even then leaving only a small portion of our undissolved gold, under heat with the concentrated solution, (where you have no need for the pure gold button to be added, Harold's trick).
And then the small additions of HCl to convert any metal nitrates to HNO3, decomposing these with more heat as the fairly concentrated, solution is re-concentrated under heat to decompose the newly formed HNO3 to NOx gases. Repeating the process if noticeable NOx fumes (red gases of NO and NO2 in damp air) are form after the addition of HCl, to the concentrated solution.(repeated for good luck) To de-NOx the limited use of HNO3 we have used. Cooling before dilution, and adding a little sulfamic acid (and, or H2SO4) to insure nitric and NOx removal, with the benefit of precipitating the lead sulfate salts, along with any silver chloride salts. and letting this set lightly covered, to sit overnight and settle well, (or in the sunlight if you wish), before carefully decanting the cooled or chilled auric chloride solution from the precipitated salts, and filtering our gold chloride solution into our clean precipitation vessel, in preparation for the gold precipitation with our reactant of choice, I believe would be a better way to go than counting on the sun, of course this is just my opinion.

Beside what else would I have to do during the solar eclipse? Sit in the dark with some welding helmet on trying to see if the sun was out or being blocked out by all of the forest fire smoke around me?


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## bigpagoda (Aug 19, 2017)

Thank you Butcher. 
I figured as much, if it did work we would all already be doing it. Hope the smoke clears out soon. I was really surprised how long it took to blow out up here.


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## butcher (Aug 20, 2017)

I cannot see it clearing until the winter rains come, a few months from now.

Some of the large fires they are just letting the forest burn up.

Why do not ask me. Ask the environmentalist that wants to take away my little wood stove to heat my small house, you know they say it pollutes the air, but a forest fire can burn naturally as they call it for months without proper management of our forest, heck they even burn homes, well I guess that is one way the environment gets cleaned up of those dangerous wood stoves, according to their logic, which I find terribly hard to understand. ???

Now with the eclipse we have an mass migration of people from the north, and from the south coming through our small communities and wilderness areas, traffic looks like major cities in small one store towns, people throwing cigarette butts out their windows, starting fires all over, city people coming to the dry UN-managed forests camping building camp/forest fires all over the country, people who know nothing about living in the woods or the forest, (many of which at home in their big polluted cities are lobbying to manage my forest/home they know nothing about (which also puts us here out of our jobs).

Heck I am 60 yrs old, and was huffing and puffing the other day trying to drag fire hose and help firefighters up the big mountain close to home where some city idiot threw out a cigarette butt and burn 35 acres (before we could contain the fire and save the homes that it threatened, I guess I am just getting old and grumpy, or at least too old to climb these steep mountains fighting forest fires some environmentalist set with a flick of his wrist, 

I do not see the smoke clearing for some time, well I guess I could try to get through traffic to buy me some hotdogs, maybe I can roast them on the coals of the forest fires, while those big city idiots camp out (close to the road as they are scared of the woods) and watch their eclipse.


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## butcher (Aug 20, 2017)

http://www.oregon.gov/ODF/Documents/Fire/FireIntelGIS/20170819_ODFFires_BriefingMap.pdf

https://fsapps.nwcg.gov/afm/


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## Topher_osAUrus (Aug 20, 2017)

That is heart breaking.
The devastation is beyond my worst imagination.

I dont have cable tv.
I don't watch the news, and really I dont read the newspaper much anymore as it seems its all politics and b.s., so I hadnt heard of the fires until mentioned here.

I hope you stay safe, and those damn city slicker hippies start to realise that their butts and roaches can go in their car's ashtray, for the sake of you and everyone else up there's life, well being, and homestead.


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## FrugalRefiner (Aug 20, 2017)

Deer are so resilient. I have a doe with a fawn that lives around our old house. She has a series of parallel scrapes along one side that show she was hit by a car and slid a fair way down the road, but she and her fawn seem to be doing well.

Dave


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