# Nitric acid and ag help



## Diver388 (Apr 10, 2014)

I've searched and searched and have found different answers. Or a thread asking a question and it totally gets high jacked etc. 

I'm new to the realm of refining and have done a good bit of research as far as the process goes. 

My question here is 1-1.3ml per gram of .925ag adequate enough. Supposedly the nitric is 70% reagent grade 
By volume or if it's 70% diluted I'm not sure yet trying to get an answer. 

I ran a small test and it seems extremely weak. 

Another one I can't seem to find is at 70-80f how long should a thin piece of sterling take to dissolve in a ball park figure from experience. ? 
I took a small piece of a spoon and overnight it's still there. Forgot the exact weight a few grams at least. 

I'm sure I'll have more questions as I progress but I would like to at least build some information in my own thread that I can refer to easily. Thanks everyone.


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## butcher (Apr 10, 2014)

Dilute the 70% nitric acid with water it will react better with the silver, heating is also a big help after initial reaction.


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## Diver388 (Apr 10, 2014)

Yeah I'm getting everything today for heating it up some to speed the process. 

It's my first time using nitric and it just doesn't seem to be reacting much at all. Really didn't get any gas at all until I stirred it some. 

Just trying to figure out if I got the shaft on the quality of nitric. Or if it's really that weak of a reaction. 
The initial reaction wasn't really vigorous or anything. 

Really think I got the shaft lol


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## Westerngs (Apr 10, 2014)

The problem is that you appear to be using 70% nitric straight out of the bottle.

If you have read as much as you claim, you would know that you need to dilute the acid with water (distilled or deionized), otherwise the acid passivates the silver and the reaction stops.

Heating also helps.


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## Diver388 (Apr 10, 2014)

Well doubtful I can find the article again but what I have read never suggested diluting before dissolving with 70%. 

Only diluting after dissolving before cementing. 

I have read a lot and read a lot of different processes. Of which I am trying but hitting an obstacle that didn't follow the process. I stopped and decided to ask and find out why. So what I claim to read and what I read actually being reliable I can not honestly say yano. I didn't write what I read over the last few weeks. 

And nothing I've read gives a time frame of how long it should take roughly. 

Thanks for your help. 

Please share an article that I may or may not have found so I can expand my knowledge.


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## torscot (Apr 10, 2014)

Def. use your acid 50 /50 with water. DO NOT use tap water, as it has impurities that will totally mess up the process. Add the acid to the water, in small amounts til the silver is gone, then you don't use too much. Heat is the secret. A small hot plate from the salvation army or goodwill store will do, Make sure you do this in a covered dish, Outdoors if no fume hood. Those red fumes, don't breath them. Even to see what they smell like. They'll hurt you real bad! Worst case. Pushing up daisies. Do not bring to boil. Time frame to dissolve cold in only 70% nitric, Some day, some time, weeks, if ever..? In 50 50 acid water with heat, a few grams, minutes to an hour. Take the piece you have had in the acid back out, rinse it, and give it a brushing with a wire brush, Don't touch it with bare hands (use gloves)even after cleaning. Your skin could be black for weeks. it may have a very thin coating of silver chloride now on the surface from being in the concentrated nitric. Nitric will not attack chloride, it will NEVER dissolve. That's a readers digest version. get more details from the site. Everythings on the site here, and yes, I agree some of it's buried deep in crap. But, it's all there. I learned from here by digging and reading and sacrificing some silver to learn. I cut and pasted everything of value into a MS word file printed it and bound it. Good luck. It's a great feeling when you pour your first bar!


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## Diver388 (Apr 10, 2014)

Well I'm not to far off then. Must have missed the part about diluting down 50/50 somewhere in the mix I never read that until it said dilute the silver nitrate down to cement. 

I will def get the heat going and that'll help then. 

I work everyday with oilfield chemicals and crap I don't even know what it is half the time because if trade secrets I know all about the ppe and going over board for protection. 

Thanks again for the info and I will do some more digging tonight before I progress and try again. 

Thanks bud


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## goldsilverpro (Apr 10, 2014)

Diver388

We don't do "time frames" in this business. Whatever it takes, that's what it takes. You just have to know what what you're doing and what you're looking for. Refining is normally not a 1,2,3 thing, unless you're running the same thing all day, every day - with that, you can develop some "time frames."


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## Diver388 (Apr 10, 2014)

Yeah I can understand that. Being lots of variables involved. Was just curious if there was. 

I have a lot to learn for sure. But I'll get there with some decent resources so acquire the knowledge from. 

Thanks


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## Diver388 (Apr 11, 2014)

Well made another test solution tonight with a few grams silver and ran it diluted with water and added nitric little by little. Much better. Was vigorous at ambient temp and didn't take long to dissolve. Added another small tiny piece and Notta just a few small bubbles nice and blue. 

Now need to seperate out some more scrap and try and figure out my ratio for solution accordingly and get enough together to cement out. The copper buss bar I'm using is pretty big so I'd like to get more solution to make it worth while. 

Once that's done and I recover some powder. I'll try and post a few pics. 

Other than that fixing to go working on the electrical side of my silver cell. 
Planning on doing an experimental small one. Will read through the treads and find what I can about the silver cell solution concentration etc.


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## Ian_B (Apr 11, 2014)

Make sure you rinse your silver powder after the copper drop well, if you do not you will have some very unpleasant and unhealthy fumes to deal with once you put the torch to the powder.

Depending on what this scrap is you are running you might want to add a couple drops of Sulfuric acid to the silver nitrate solution to precipitate out any possible lead nitrate as lead (II) Sulfate then filter solution discard (properly) the lead and treat solution with copper.


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## Diver388 (Apr 11, 2014)

Thank you for the info. I have plenty of distilled water ready to go. 

Currently I'm running some tests on some sterling I have to get it figured out and running smooth. 

Should have a decent batch to drop by the weekend. Wash it and might try some in the silver cell if I get it going


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## Diver388 (Apr 12, 2014)

Well the test worked out good. Made some more dropped it. Decanted. Washed washed washed washed. 

Now drying.  

Anyone have an easier way to remove the silver cement from the filters or just spray and wash into another beaker until clean and let it settle before decanting again to get the last bit.


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## necromancer (Apr 12, 2014)

funnel with fiberglass plug ......

Buchner funnel with good filters and a vacuum .......

dont worry about every drop of silver, just save up filters for a later day ..........


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## Ian_B (Apr 12, 2014)

If you let the silver powder dry out on its own in the filter paper you will be able to get most of it. the only down size is it takes time to let it dry on its own, but it is worth the wait.


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## Diver388 (Apr 12, 2014)

Also I'm curious cause I did one solution and totally spent the nitric til it wouldn't dissolve anymore even while heated. 

Decanted removed the remaining piece diluted solution 50/50 for cementing. Solution was room temp by then and applied smashed copper pipe. Solution started cementing and acted like there was free nitric attacking the copper and cement floating and redissolving. Removed copper. Tried again to dissolve more silver. No success. 

Went back to cementing shortly after cooling. Again acted as free nitric attacking the copper. Slowed down after a little and some copper was dissolved into solution and started cementing better. 

What am I missing here why is it attacking and dissolving the copper into solution without dropping silver. But I can't get it to dissolve a clean piece of silver as if the nitric is spent ? 

Thanks.


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## Diver388 (Apr 12, 2014)

Roger that. Yeah I currently don't have much of a lab set up. Working with what I have for now seeing if it's something I want to pursue further before order a bunch of equipment. 

I did watch a video with a vac filter it is pretty sweet. 

And I figured that much. I tried to stare it dry but wouldn't work. Being my first go at it I'm excited and ready for the finished product.  

Thanks guys.


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## necromancer (Apr 12, 2014)

i have heard not tried.....

putting filter with silver powder on a cooking hotplate on very low heat

cheap http://www.walmart.ca/en/ip/6085201-George-Foreman-Griddle-/6000002969251


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## Diver388 (Apr 12, 2014)

Lmbo. That's very similar to what I just went and picked up.  

Any idea on my other post? I'm left scratching my head there


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## necromancer (Apr 12, 2014)

Diver388 said:


> Lmbo. That's very similar to what I just went and picked up.
> 
> Any idea on my other post? I'm left scratching my head there



which one.......


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## Diver388 (Apr 13, 2014)

About the nitric attacking the copper but not dissolving any more silver. Few post up


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## Diver388 (Apr 13, 2014)

Also my silver came out really fine like a paste. Is that caused by to much free nitric in the solution making it do that. 

I did have one small batch more plump and fluffy. 
Thanks


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## necromancer (Apr 13, 2014)

Diver388 said:


> Decanted removed the remaining piece diluted solution 50/50 for cementing. Solution was room temp by then and applied smashed copper pipe. Solution started cementing and acted like there was free nitric attacking the copper and cement floating and redissolving. Removed copper. Tried again to dissolve more silver. No success.



1 - did you weigh the second bit silver before and after?

2 - what did you use to smash the copper pipe ?

3 - was the 50/50 blue green or aqua blue



Diver388 said:


> Went back to cementing shortly after cooling. Again acted as free nitric attacking the copper. Slowed down after a little and some copper was dissolved into solution and started cementing better.



1 - what do you mean by "after cooling" you said it was room temp.



Diver388 said:


> What am I missing here why is it attacking and dissolving the copper into solution without dropping silver. But I can't get it to dissolve a clean piece of silver as if the nitric is spent ?



1 - how do you think the copper drops silver if there is no nitric in solution. if there is zero free nitric the copper would just sit there.


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## Diver388 (Apr 13, 2014)

necromancer said:


> Diver388 said:
> 
> 
> > Decanted removed the remaining piece diluted solution 50/50 for cementing. Solution was room temp by then and applied smashed copper pipe. Solution started cementing and acted like there was free nitric attacking the copper and cement floating and redissolving. Removed copper. Tried again to dissolve more silver. No success.
> ...



You have to have some free nitric for the ions to swap from what I've read. Which I understand. I was just surprised that no silver would dissolve further into the solution meaning close to no free nitirc correct??

But the copper getting attacked dissolving it. Not cementing what did re dissolved or floated. Meaning to much free nitric correct?? 

Well I didn't add any nitric anywhere so I'm lost why to the copper wanted to readily react and dissolve and not drop silver 
But silver would not dissolve even when heated. 

Thanks


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## necromancer (Apr 13, 2014)

how long did you leave the copper bar in ?

and do you use the same bottle in the picture you posted ?


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## Diver388 (Apr 13, 2014)

i only left it in the first time for just a minute or so when it starting reacting strong floating what little cement did try and drop i knew it was to strong so removed.. 

the second time i left it in there until it calmed down filled the nitric and started dropping cement. since i couldnt get it to dissolve silver any more. I just let the copper take up the remaining nitric that was reacting.


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## necromancer (Apr 13, 2014)

Diver388 said:


> i only left it in the first time for just a minute or so when it starting reacting strong floating what little cement did try and drop i knew it was to strong so removed..
> 
> the second time i left it in there until it calmed down filled the nitric and started dropping cement. since i couldnt get it to dissolve silver any more. I just let the copper take up the remaining nitric that was reacting.



you should be ok but i can't understand what you meant by:


Diver388 said:


> Solution started cementing and acted like there was free nitric attacking the copper and cement floating and redissolving.



your silver was redissolving in solution after the copper was added to the solution and after it started to cement :?: 

don't know why your added silver would not dissolve and your cementing silver did :!: :?: 

it leads me to wonder.....

*"do any other forum users have a possible answer to this"*

only thing that comes to mind is: (guessing)

#1 - first time your silver wasn't floating but was being pushed to the top by the (bubbling) reaction
#2 - borax coating on the silver you added (that did not dissolve)


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## solar_plasma (Apr 13, 2014)

If you aren't sure, if all silver is reduced, you can take some drops from the solution to a spot plate or a test tube and add a drop HCl or any soluble chloride. A white cloud shows silver. If there is silver, just leave the copper in it as long as it takes to cement all silver. It has been mentioned before, that a little excess nitric is needed. That might take some time. Alternatively I would just drop the last gramms as AgCl and store it wet and dark.



> "do any other forum users have a possible answer to this"



I would guess, it just looked as if...


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## necromancer (Apr 13, 2014)

solar_plasma said:


> I would guess, it just looked as if...



as i thought (thanks), table salt was my next answer


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## Diver388 (Apr 13, 2014)

yes when i applied the copper some cement tried to cement it was very fine and floated and dissolved. and a clear reaction the nitric attacking the copper and bubbling making gas etc dissolving the copper in the solution without dropping cement with room temp solution.. when i tried to dissolve silver again it wouldnt room temp or heated and on clean silver that was scrubbed. no more silver would react.. \

went back to copper at room temp shortly after and would react. once the copper filled the solution then it started cementing silver..

and the piece of ag i used i later dissolved in another batch without even scrubbing it...

yes im left scratching my head as well


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## g_axelsson (Apr 14, 2014)

you do not need any nitric acid for the cementing to work. You can demonstrate that by cementing silver nitrate with copper.
[youtube]http://www.youtube.com/watch?v=rgYhkVy5cBU[/youtube]
But it can speed up the reaction as it creates a clean copper surface and I suspect that it also helps to get the silver moss not to hang on so hard..

The reason why silver stopped to dissolve and then started again when there was some cemented silver is probably related to the surface area. You said you "scrubbed the silver", it sounds like a big solid piece. It can be hard to see if there is a reaction. The cemented silver on the other hand have a huge surface area and reacts swiftly with even weak nitric acid.
There could also be another explanation, your silver nitrate got saturated, then the surface would be covered by a thin layer of silver nitrate as it doesn't dissolve in the saturated solution. As soon as the copper starts to cement the silver it also lowers the concentration of silver nitrate in solution so more can be dissolved. Therefore the cemented silver was attacked.

This is of course purely speculations from my side.

As a tip, I have a beaker with water and salt in it (NaCl) where I dump my left over silver nitrate solutions, it's my silver stock pot. I also use it as a quick test for dissolved silver, just put a drop of the solution in it and you see if there's a white cloud formed - silver chloride.
When the beaker have enough silver chloride accumulated I treat it with lye (NaOH) to turn it into silver oxide and then dissolve it directly with nitric acid.
I think I should add some copper wire to the salt beaker to catch PGM:s by cementation.

Göran


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## solar_plasma (Apr 14, 2014)

> But it can speed up the reaction as it creates a clean copper surface and I suspect that it also helps to get the silver moss not to hang on so hard..



Thanks for explaination! I always wondered why the little free nitric was needed or at least useful.


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## necromancer (Apr 14, 2014)

Yes great explanation, i guess i over analyzed it :shock: not that i have ever done that before... :!: ...


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## Diver388 (Apr 14, 2014)

Thank you. And yes after each drop and decant filter I test with hcl. 

And I do understand the above with the nitric.

The piece was small 1/4" or so piece from the thin part of a spoon. .925 

I was just really curious why it wouldn't react slightly enough to see with heated solution. 
But yet the solution attacked the crap out if the copper at room temp and floated the little cement that did form. 

I've read that seeing gas. floating cement and cement going back into solution meant to much free nitric. 

But no silver would dissolve any way I tried. 

So second attempt at cementing I let the solution eat the copper until it stopped. Well almost stopped. and started to really cement silver like it should.


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## Diver388 (Apr 14, 2014)

Update: 

Well I didn't have much to process. Nor did I want to since it was my first go at it. 

Thank you guys for all the help. 

Recovery came out to a little over 2.5 ozt  
Nice and sparkly. 

Thanks again


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## g_axelsson (Apr 14, 2014)

Diver388 said:


> Nice and sparkly.


And that is why we love doing it! :mrgreen: 

Göran


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## Diver388 (Apr 14, 2014)

Lol yup. Now I just have to find more scarp silver. That's the hard part.


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## necromancer (Apr 14, 2014)

Diver388 said:


> Lol yup. Now I just have to find more scarp silver. That's the hard part.



don't under estimate yourself !!!!!!


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## Diver388 (Apr 29, 2014)

Finally got my hands on some decent price sterling. 

Should have a nice big batch to start working on. Will post some results. 

Lot of damaged jewerly and a big sterling bowl. 543g. 

Will try and get my silver cell going this week and get some pics of it as well.


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## Diver388 (Apr 29, 2014)

And here's some end result from my last little test batch I was dabbling with.


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## Diver388 (May 2, 2014)

Few update pictures  two 1ozt bars from cement silver 

And 1ozt bar from my silver cell. 

I can not seem to get it to pour the whole mold. I've tried everyting that I know. Silver nice and molten. Graphite mold is pre heated. Just cools before it lays down. Any suggestions?


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## Diver388 (May 2, 2014)

My cheaply made silver cell. Whatever it works


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## Diver388 (May 5, 2014)

Some cell results.


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## Smack (May 5, 2014)

Get everything hotter. I would also say don't pour in one spot but that's hard with this small of a pour.


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## Diver388 (May 5, 2014)

Thanks bud. Yeah small pours are pretty tough. Especially with only experience I do have is with lead making fishing weights. 

The rest of what I had ready I just poured half and quarter ozt buttons. They came out nice. 


Made me a ported furnace to set my crucible on to help keep some heat on it. Use propane for it and map gas on top.


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## Diver388 (May 6, 2014)

Thanks bud. Yeah still trial and error. Practicing. 

Looking good though once I get the pour down. 

Working on a furnace now that will help out a lot to get some extra heat going when I'm doing it by myself. 

Anyone know what the ideal temp is for pouring small silver bars? 

Would be interesting to know and do some pours and shoot some readings


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