# Silver question regarding the use of salt VS hcl



## Xydoman (Dec 25, 2021)

Can someone tell me what the differences are between adding salt VS adding hcl to a silver nitrate solution to make silver chloride? Mainly curious about yield, but I'm interested to know any other differences too. 

And on the same note, are there differences between adding sugar as opposed to adding Karo syrup, or honey or one of the many other sweet syrupy concoctions to your silver oxide during refining? I've used just about all of it and I do have different size buttons to show for each batch, but this could also be due to material type and quality that was processed. Thanks yall. Loom forward to reading what yall have to say.


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## butcher (Dec 26, 2021)

Not much difference in your silver product with what type of chloride salt you use, but your waste byproducts will differ.

AgNO3 + HCl --> AgCl + HNO3
Silver chloride is insoluble in a Nitric acid solution (as well as the with other metal ions remaining in solution).

AgNO3 + NaCl --> AgCl + NaNO3
Silver chloride is insoluble in a solution of sodium nitrate (along with other metal ions remaining in the solution.

AgNO3 + KCl --> AgCl + KNO3
Here our solution is potassium nitrate with remaining soluble metal ions and our silver chloride.

Sugars can be glucose or dextrose... Basically different types of sugars. which is more of a question for a chemist more familiar with organic chemistry, than the inorganic chemistry that we normally deal with here on the forum.


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## cejohnsonsr1 (Dec 26, 2021)

_I’m not sure what you’re starting with, but if you dissolved your silver with distilled water and Nitric, there’s really no reason to convert to silver chloride. You can just cement the silver out of solution with copper in 1 step. Sreetips frequently demonstrates using a very small sample of the solution and a few drops of HCl to verify that all the silver has cemented out and he demonstrates how to recover and refine with household chemicals that involves precipitation of silver chloride and conversion back to the regular mud you’d get from cementing, but it seems like a pain to me because it takes longer, involves more steps and produces more waste. Either method should produce the same yield if the process is performed carefully. _


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## Yggdrasil (Dec 27, 2021)

Xydoman said:


> Can someone tell me what the differences are between adding salt VS adding hcl to a silver nitrate solution to make silver chloride? Mainly curious about yield, but I'm interested to know any other differences too.
> 
> And on the same note, are there differences between adding sugar as opposed to adding Karo syrup, or honey or one of the many other sweet syrupy concoctions to your silver oxide during refining? I've used just about all of it and I do have different size buttons to show for each batch, but this could also be due to material type and quality that was processed. Thanks yall. Loom forward to reading what yall have to say.


As you see from Butchers explanation below, with NaCl and KCl
You create Sodium or Potassium Nitrate.
But on the other hand with HCl you basically revives the Nitric and precipitate AgCl.
So if this is done carefully you can reuse the Nitric many times.



> AgNO3 + HCl --> AgCl + HNO3
> Silver chloride is insoluble in a Nitric acid solution (as well as the with other metal ions remaining in solution).


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## kurtak (Dec 28, 2021)

Xydoman said:


> Can someone tell me what the differences are between adding salt VS adding hcl to a silver nitrate solution to make silver chloride? Mainly curious about yield, but I'm interested to know any other differences too.



Ether one (table salt or HCl) will precipitate silver chloride - for that matter any chloride will

As butcher pointed out it becomes a question of the byproduct you end up with after you precipitate the AgCl (depending on the chloride used)

As a matter of my personal experience I found that using HCl produced a heavier AgCl precipitate (larger participles) then table salt which made for better settling of the AgCl when washing out the acid so as a personal choice I used HCl 


Xydoman said:


> And on the same note, are there differences between adding sugar as opposed to adding Karo syrup,



There are two "*basic*" types of sugar (though "*several*" sugar chemical compositions in each type) 

The (two) types are - reducing sugars - or - non-reducing sugars

The question being whether or not the carbon atoms in the sugar are available to act as a reducing agent - or not

Example(s) of reducing sugars are dextrose & fructose --- corn syrup can be ether dextrose or high fructose sugar depending on how it is made --- so the carbon atoms in the sugar are more available to act as a reducing agent

example of non-reducing sugar sucrose sugar --- table sugar (or cane sugar) is a sucrose sugar --- so the carbon atoms are less likely to act as a reducing agent

To put it in context --- when you use the salt/lye/sugar method --- you first add a chloride (salt) to make AgCl you then ad lye to convert the AgCl to AgO (silver oxide) you then add sugar to the AgO to reduce it to Ag (silver)

So --- although you MAY be able to reduce (some) AgO to Ag using table sugar it is likely the reduction will not be complete as it's reduction properties are less effective/efficient at reduction then corn syrup --- that can lead to loss of silver during melting if the melting conditions are not controlled (some of your silver can go up in smoke)

Therefor you should use corn syrup for reducing your AgO to Ag --- you will get more effective/efficient & complete reduction

For what it is worth --- some people suggest first dissolving there lye & sugar together then adding the lye/sugar to the AgCl thereby doing the conversion & reduction in one step & that's fine if you are doing "small" batches (a *few* ozt) --- however - if you are working with larger batches (pounds) I do not recommend doing so

Why ?

Because your lye/sugar waste is going to be HIGH Ph (like Ph 13 - 14) --- high Ph waste is considered *hazardous* waste & so needs to be adjusted to a Ph between 6 - 8 to be considered safe for disposal 

The problem of adjusting the lye/sugar solution down in Ph is that around Ph 11 you start precipitating the sugar out of the lye --- it precipitates out as a VERY thick/heavy sugar foam that does not dissipate (foam does not go down) & does not separate (foam on top - liquid on bottom) the foam makes it impossible to filter --- before you reach Ph 8 (the high end of your target Ph adjustment) you will have a sugar foam so thick you can't stir it to finish adjustment & due to the foaming have 3 -4 times the volume you started with

It's one thing to dump a gallon or two of lye/sugar down the drain (without adjusting Ph) - its another thing doing it with larger volumes

Because of the above - the lye/sugar waste can not be used for adjusting the Ph of other acid waste solutions

So if you convert you AgCl to AgO with lye only - then wash the lye out - you can use that lye to adjust Ph of other acid waste --- then when you use the sugar only (the lye has been washed out) to reduce your AgO to Ag & you wash the sugar out you have only sugar water which can go down the drain 

For what it is worth

Kurt


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## Xydoman (Jan 5, 2022)

cejohnsonsr1 said:


> _I’m not sure what you’re starting with, but if you dissolved your silver with distilled water and Nitric, there’s really no reason to convert to silver chloride. You can just cement the silver out of solution with copper in 1 step. Sreetips frequently demonstrates using a very small sample of the solution and a few drops of HCl to verify that all the silver has cemented out and he demonstrates how to recover and refine with household chemicals that involves precipitation of silver chloride and conversion back to the regular mud you’d get from cementing, but it seems like a pain to me because it takes longer, involves more steps and produces more waste. Either method should produce the same yield if the process is performed carefully. _


I've used the copper method too and it is way easier. But it's all for fun and satisfaction for me. Watching the AgCl form in a solution scratches the same itch that gets scratched like say, when I vacuum a floor? Or squeegie a window.. Lol, yeah I've been called a wierdo once or twice.


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## Xydoman (Jan 13, 2022)

Yggdrasil said:


> As you see from Butchers explanation below, with NaCl and KCl
> You create Sodium or Potassium Nitrate.
> But on the other hand with HCl you basically revives the Nitric and precipitate AgCl.
> So if this is done carefully you can reuse the Nitric many times.


That's interesting.. BTW, the equations when written out, confuse the fire out of me, as I've never studied chemistry in depth. Altho I'm starting to see that it would be in my best interest to at least learn how to read them.. But I have a basic understanding I think.. Let me know if I have this correct...

AgNO3 + HCl --> AgCl + HNO3

Does this mean that if I use hcl to turn my AgNo3 (silver nitrate) into AgCl (silver chloride), once I remove the AgCl, I'll essentially have Hno3 (nitric acid) remaining?? Please pardon the redundancy in parenthesis, I just want to make sure I understand, and if I happen to be wrong about an abbreviation it will allow you guys to correct me.

So, This might sound like a dumb question.. But is this remaining nitric able to be reused for the same purpose? If so, this has been an incredible breakthrough for me and I owe you guys on this thread something huge! Please let me know or point me to some concise instruction that could possibly help me figure this out. 

If I keep spending 150 bucks every month on nitric acid I'm afraid I'll be looking at divorce papers on the floor of my new bachelor pad eventually lol.


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## FrugalRefiner (Jan 13, 2022)

You have the concept and the chemistry correct. There are a couple of considerations.

First, you want to use not quite enough HCl to precipitate all the silver. If you use too much, you'll now have excess Cl- in your acid, which will interfere with subsequent use. By using not quite enough, you'll still have just a bit of AgNO3 left in solution with relatively clean HNO3.

I say relatively clean HNO3. It depends on what else you've dissolved along with the silver. If you've dissolved sterling silver, you'll also have some copper nitrate in your revived acid. If you've dissolved jewelry, you could have any number of other metals in solution.

You also have to consider dilution. We usually add about an equal amount of distilled water to our nitric when dissolving silver. So the acid concentration has dropped from around 68-70% (concentrated nitric acid) to around 34-35%. Then you add HCl, with is usually somewhere around 32%, so you've further diluted the acid. Concentrating the silver nitrate solution prior to using the HCl can help, but it may cause some of the silver nitrate to precipitate (it's why we dilute the acid to begin with). Concentrating after using the HCl will evaporate some of the nitric you've regenerated.

I'm not saying it's not doable. It is. Just be aware of the pitfalls.

Dave

edited to correct chemical formula


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## orvi (Jan 13, 2022)

kurtak said:


> Ether one (table salt or HCl) will precipitate silver chloride - for that matter any chloride will
> 
> As butcher pointed out it becomes a question of the byproduct you end up with after you precipitate the AgCl (depending on the chloride used)
> 
> ...


Reducing Ag2O to metallic Ag is relatively easy also with many other organics. Just temperature and basicity is the key point. Ag2O is relatively strong oxidant.
From many observations of many people, reduction of silver from Ag2O with regular tablesugar (sucrose) isn´t stechiometric in that way only aldehyde part of molecule reacts. Meaning, that more silver oxide molecules are reduced with just one molecule of sucrose.
At high temperatures and basicity, just any reductable organic accomplish this reaction. Aside from aldehyde functionality which is present in glucose - making it "reducing sugar", other parts of the molecules would be also oxidized, eg other hydroxygroups etc...
Last time i did small scale Ag refining from AgCl leftovers, I made 87 grams of silver, using just under 25 grams of regular sugar (and this was still bit excessive). Monitoring the reaction via thermometer is very convenient. Starting above 90°C, adding sugar in portions with stirring/swirling and measuring temperature in between additions. When more sugar did not cause any measurable exotherm, it´s over. I never had the problem with leftover chloride residues or some unreacted stuff making weird things (altough I admitt to experience charring after bad rinsing). At elevated temperature, Ag2O spontaneously decompose to metallic Ag and oxygen, so any traces of unreacted Ag2O will reduce back to the silver and stay in the crucible, nicely under protective soda flux - in case that some AgCl was persistent even to the melting stage


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## Stibnut (Jan 14, 2022)

One other wrinkle regarding sucrose: it's not a reducing sugar by itself, but under acidic conditions and high temperatures, it will split into a molecule of fructose and one of glucose, which are both reducing sugars and will then reduce your silver oxide. 

Also, corn syrup isn't just glucose and/or fructose, it contains longer sugars as well including maltose, maltotriose, and longer dextrins. Each of those are reducing sugars but are only 1/2, 1/3, etc times as strong per weight because only the glucose unit at one end has a free aldehyde group. So you'll have to add a significant excess of syrup to reduce all the Ag2O and anything else that can be reduced.


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