# 7 Liters of Nitric in 200 Liters Of Water.



## razvanflorin (Aug 7, 2016)

Hi Dear Friends ! i have some problems. 
I have processed before 1Tone of silver plated aluminium boxes in nitric acid, i have percipitated with copper and got 7.5 kg of Silver, that's okay for me.

i have procesed them in an 1000 Liters vessel cuted from the middle adding about 200 kg of aluminum boxes, wait to dissolve the silver then put the boxes out, wash and add anothers.

The Second time i have made a smaller bath of 500 kg and got 4 KG of silver.

This one was made in a 100 Liter vessel , adding about 40 kg of aluminum at once, wait for silver to dissolve then add anothers.

The difference is that from the first batch i have got 0.75% of silver.
And from the second bath i have got 0.80% of silver.

My mistake is that in both of them i have used a lot of Nitric . 
in the first one i have used 100 liters of 50% nitric and 100 liters of water.
in the second one i have used about 30 liters of nitric and 30 liters of water. ( i don't remember exactly) it was a very long time ago.

in fact i wanna say that i have used alot of nitric. in the second much and in the first very much !
the differnce of silver quantity it is of 0.05% , everybody can tell me that is because i have lost it in washings, filterings or the purity of silver was bigger/lower. sure, why not ? but the bigger problem is that one of my friend just processed a little bath of 10 kg aluminium and got 1% of silver, this is a big difference for me.

so now, what i want to ask is about that:
i have used 100 liters of nitric and 100 of waters for a low quantity of silver
then i have used a lower quantity of nitric and got a bigger yield.
my friend have done a test batch of 10kg of aluminium so he used a very low quantity of nitric, and got a bigger yield.

it is quite clear to me that i have to use just the need nitric for my quantity of silver. ex: 1 liter of 50% for 1 gram of silver. i have used a lot more before to make it work faster. 

so again i have got a big quantity of aluminium, about 700 KG so i have to use 7 liters, i need a batch of 200 liters of water. would it work? 7 liters of nitric in 200 liters of water? how faster? it would work enough better if i simmer it ?


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## anachronism (Aug 7, 2016)

Firstly don't look as this as a mistake. Look at it as an really good learning experience.

What you are learning here is that everything is a trade off when it comes to leaching. With regards to many kinds of leaches, strong leach solutions are faster BUT less selective, whilst weaker leach solutions are slower BUT more selective. This is demonstrated by your own figures above. Also you need to ask how you are sure that all the silver has in fact been removed. 

The question I would be asking is whether you prefer speed over accuracy and percentage of leach, because as I said earlier - it's a trade off. You can find an optimum balance that suits your own requirements but you can't have both. 

Could I ask what the base material is and whether it is telecoms?

edit for spelling.


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## razvanflorin (Aug 7, 2016)

anachronism said:


> Firstly don't look as this as a mistake. Look at it as an really good learning experience.
> 
> What you are learning here is that everything is a trade off when it comes to leaching. With regards to many kinds of leaches, strong leach solutions are faster BUT less selective, whilst weaker leach solutions are slower BUT more selective. This is demonstrated by your own figures above. Also you need to ask how you are sure that all the silver has in fact been removed.
> 
> ...



Aluminium, yes it is telecoms.


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## anachronism (Aug 7, 2016)

Nortel/Ericsson RF equipment?


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## razvanflorin (Aug 7, 2016)

anachronism said:


> Nortel/Ericsson RF equipment?


I think ericsson, but i'm not sure, why do you ask ?


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## anachronism (Aug 7, 2016)

I deal with a lot of this material as a company. i.e. I don't refine it myself but we dismantle large amounts, so your product sounded similar. Hence the question. Call it an educated guess if you like  

If it's this kind of product then the plating varies dependent upon the actual component within the unit if that helps. I'm intrigued as to your yields though, and my comments still stand with regards to the leach itself.


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## razvanflorin (Aug 7, 2016)

anachronism said:


> I deal with a lot of this material as a company. i.e. I don't refine it myself but we dismantle large amounts, so your product sounded similar. Hence the question. Call it an educated guess if you like
> 
> If it's this kind of product then the plating varies dependent upon the actual component within the unit if that helps. I'm intrigued as to your yields though, and my comments still stand with regards to the leach itself.


Hmm.. it is possible, i got many kind of models and i proccess them togheter...
after you/your staff dismantle the materia (aluminium boxes), do you sell them ? :roll: :mrgreen: i would be interested to buy them :lol: where are you from ? (if you're interested answer in private message please)


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## anachronism (Aug 7, 2016)

Haha sure I will drop you a PM. Nothing ventured nothing gained- it might work out well for us both, and that would be a win.


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## g_axelsson (Aug 8, 2016)

razvanflorin said:


> Hi Dear Friends ! i have some problems.
> I have processed before 1Tone of silver plated aluminium boxes in nitric acid, i have percipitated with copper and got 7.5 kg of Silver, that's okay for me.
> 
> i have procesed them in an 1000 Liters vessel cuted from the middle adding about 200 kg of aluminum boxes, wait to dissolve the silver then put the boxes out, wash and add anothers.
> ...


You used 100 liters of nitric and dissolved 7.5 kg of silver. Then used copper to cement the silver... that must have taken a lot of copper to use up the approximately 90 liters of nitric left in solution.

A wise man said... well, it was Goldsilverpro, that in a similar situation an easy way to remove the silver while rejuvenating the leach and not killing the nitric is to precipitate 90% of the silver with hydrochloric acid. The silver chloride can be filtered off or the nitric decanted. Then the leach can be reused again until the nitric is used up.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=6215&p=54669&hilit=stainless+steel+silver+chloride#p54669

As for the difference in yield, size matters. Generally, if you have smaller components the surface area to weight ratio is higher than for larger components. There could also be differences in plating thickness. So if your friends batch wasn't identical to yours in composition the numbers could differ from natural causes and not because you are losing silver.

And yes, heating will increase the reaction speed. Agitation will also increase it.

Göran


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## upcyclist (Aug 8, 2016)

I'm curious, how do you know when you have dissolved all of the silver? Won't it cement on the aluminum until the Al is gone?

Edit to add: or does aluminum passivate in nitric?


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## Topher_osAUrus (Aug 8, 2016)

Aluminum passivates in HNO3


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## Lou (Aug 8, 2016)

In strong HNO3. I'm not sure what concentration but sometimes the two are not compatible.


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