# Silver from Caustic Sticks



## ibycus (Mar 9, 2016)

I have easy access to a supply of used caustic sticks. The sticks contain silver nitrate and potassium nitrate as their active ingredient. I'd like to (for fun) try to recover the silver. 

Here is what I have so far: 

The nitrates are readily dissolved in water. Adding clean copper should precipitate out silver (at the expense of the copper)

Right now the precipitate I'm getting is mostly a black sludge and not the pretty looking gray 'cement' you see on all the videos. 

I'm thinking I might be getting silver oxide formed rather than silver, and was reading that reacting what I made with hydrogen peroxide might fix this, (this seems weird to me so haven't tried, also thought maybe the trick of polishing silver with aluminum and an electrolyte might work, but all this is contingent on me actually having silver oxide in the first place)

Would you think the problem was caused by the contaminating potassium nitrate? Or that I used tap water? Or both?

Ultimately I'd like to recover without sacrificing the copper, but figured this is a good place to start.


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## Igigi (Mar 31, 2016)

Well i hope someone chimes in, i have a bunch of those cauterizing sticks, mine are new though, and im curious.


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## solar_plasma (Mar 31, 2016)

I do not think it is worth processing unless you have kg of tips. I could be wrong. If you dissolve ten pieces in distilled water and then adding NaCl you would get a precipitate of AgCl. You could filter, dry and weigh to know how much silver it would yield.

This is quite pure silver, so I would not contaminate it by cementing on cobber but I would use the chloride-sugar route.

Don't do any random experiments with silver salts! Don't do any random experiments with H2O2! Both can react violently under circumstances! I think there has been advised against using H2O2 as a reductant just because of possible violent reaction.


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## upcyclist (Mar 31, 2016)

solar_plasma said:


> This is quite pure silver, so I would not contaminate it by cementing on cobber but I would use the chloride-sugar route.


Or Lou's "tumble with iron in weak sulfuric" method. But I agree--cementing can make it worse rather than better. I tried that, and will stick with AgCl and conversion to Ag for now. I'll revisit that when I explore electrolytic cells.

Edit to add: Try them all, safely! But start with recommendations


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## SilverNitrate (Apr 7, 2016)

if you are sure its only silver/potassium nitrate, simply crush it up, mix with 1/4 volume sugar and burn it.


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## solar_plasma (Apr 7, 2016)

SilverNitrate said:


> if you are sure its only silver/potassium nitrate, simply crush it up, mix with 1/4 volume sugar and burn it.



Don't you think a lot of silver will go up in smoke? If it is enough potassium nitrate, I read data sheets telling 75%, I am quite sure that it will cause losses up to 90%+. Further this blend can be sensitive to friction. I burned a lot of it, when I was a child - in fact no good toy. 

Wet is the way to go, - cementing or chloride precipitation.


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## ibycus (Jun 24, 2016)

Thought I'd update on my progress. Dissolved in water, added in some copper (scrap wire). Got some nice precipitates. Filtered through some paper towel. Currently drying. Also recovered what I assume is a mix of potassium and copper nitrate (after boiling off the water)


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## razvanflorin (Jun 30, 2016)

Excuse me ! I do have a question. From where can i get "Used caustics sticks" ?

I mean, Does the private clinics selling them or just throw them in the trash ?
It is legal to buy used caustic sticks ? i'm sorry if i have created any bother , i've never seen/used any caustic stick before, but it sounds interesting (In the refining way).


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## upcyclist (Jul 1, 2016)

ibycus said:


> Thought I'd update on my progress. Dissolved in water, added in some copper (scrap wire). Got some nice precipitates. Filtered through some paper towel. Currently drying. Also recovered what I assume is a mix of potassium and copper nitrate (after boiling off the water)


Are you working with acids at all, and therefore have a stockpot and waste processing setup? If so, you could pour the used nitrates (once you are sure all values are gone) into the bucket where you're doing cementation with iron--that would drop any copper before you proceed to neutralization.


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## ExNuke (Apr 22, 2017)

What are these caustic sticks used for? Could someone post a picture?


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## UncleBenBen (Apr 22, 2017)

ExNuke said:


> What are these caustic sticks used for? Could someone post a picture?



They are used in the medical field to stop bleeding. Particularly useful in stopping nose bleeds by cauterization.


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