# silver braze



## baja's anvil (Aug 14, 2016)

Hello 
i am at best a hobbyist thinking about dabbling in refining 
my main product that i would like to refine is silver braze mostly cadmium bearing as i wont use it 
the second would be low silver content 5-15%
from what i have read the way to go would be dissolving in nitric acid 
i have some questions on details and ideas if they work
1. Dissolving in acid 
a. 50/50 works best ?
b. works faster with heat but still works without
c. working outside with a gas mask should be fine for me but how far away from others neighbors should i stay
2. Recovery 
a. hang a piece of copper in solution to cement out silver
b. cadmium will stay in salutation 
3. Questions 
a.if i bubble the nox fumes from the dissolving braze through water will it 
1. make the water into nitric acid (dilute) 
2. make the fumes safer less of a danger
b. can i electrically (thum cell) remove the silver without cementing first
c. after cementing can i electrically (thum cell) remove the copper 
d. can i reuse the acid if i remove 
1. the silver by cementing or electrically (thum cell) 
2. the copper by cementing or electrically (thum cell) 
e. can i remove the zinc electrically or other
4. clean up how?
A. nitric solution with cadmium and zinc (possibly iron from cementing copper)
1. Adjust ph to drop iron if any 
2. Cement cadmium with zinc
b. get rid of zinc and reuse acid if possible
c. neutralize acid with ____
d. disposal of iron copper cadmium zinc
i am trying to get the most out of my acid while getting rid of the cadmium 
in steps 
1. mix acid to 50/50 solution add acid to water
2. put in braze 
3. Cement on copper
4. electrically remove copper
5. Repeat 2,3,4 until it does not work 
6. Cement cadmium with zinc
7. Cement zinc with aluminum
8. perspire aluminum with salt 
9. neutralize with ___??___
10. pour down drain
can anyone help with details
thanks baja


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## butcher (Aug 15, 2016)

Hello I am at best a hobbyist thinking about dabbling in refining.
This is not something to dabble in, you need to understand the dangers, learn to deal with the waste... 
my main product that I would like to refine is silver braze mostly cadmium bearing as I won't use it
the second would be low silver content 5-15%
Caution cadmium produces toxic volatile fumes when melting
from what i have read the way to go would be dissolving in nitric acid
I personally would use hot concentrated ferric chloride making silver chloride, but that is another subject.
i have some questions on details and ideas if they work
1. Dissolving in acid
a. 50/50 works best ?
Yes 50/50 or even more dilute
b. works faster with heat but still works without
 at first you do not want to heat unless the nitric is extremely dilute, the reaction can generate its own heat, heating at the end of the reaction becomes much more important.
c. working outside with a gas mask should be fine for me but how far away from others neighbors should i stay
Most all gas masks will not protect you from the fumes.
2. Recovery
a. Hang a piece of copper in solution to cement out silver
b. Cadmium will stay in solution
3. Questions
a.If i bubble the NOx fumes from the dissolving braze through water will it
1. make the water into nitric acid (dilute)
2. make the fumes safer less of a danger
NOx is a combination of different Nitric Oxide gasses, NO2 gas (red gas) is soluble in water and can make a dilute HNO3, some H2O2 in solution can help, one problem is keeping the gas in solution long enough to fully react. NO gas (clear gas) is not water soluble, with oxygen it can form NO2 gas (here the peroxide can help). 
b. can i electrically (thum cell) remove the silver without cementing first
No
c. after cementing can i electrically (thum cell) remove the copper
 Too much copper contaminates the cell, you can study it more.
d. Can i reuse the acid if i remove
1. The silver by cementing or electrically (thum cell)
2. The copper by cementing or electrically (thum cell)
Most of the acid is turned into salts in the reaction, you can recover some, but it is too complicated to explain here in one post, a study of the forum can give you several ideas of ways it can be done.
e. Can I remove the zinc electrically or other
Too complicated basically I will say no for all practical purposes.
4. clean up how?
See dealing with waste in the safety section.
A. nitric solution with cadmium and zinc (possibly iron from cementing copper)
Salts of metals, I am not sure what the question is here.
1. Adjust ph to drop iron if any
Yes see dealing with waste
2. Cement cadmium with zinc
Will not work see the reactivity series of metals.
b. get rid of zinc and reuse acid if possible
Forget it.
c. neutralize acid with ____
NaOH, lime ...
d. disposal of iron copper cadmium zinc
See dealing with waste
i am trying to get the most out of my acid while getting rid of the cadmium
in steps
Nitric can be hard to get and expensive, unless you can get it cheap I would look into recovering the silver some other way, your talking about using up a lot of acids on base metals to recover silver (not that expensive of a metal) you may end up spending more money to get silver than you could go buy it for, even then your talking about a lot of waste to deal with...
1. mix acid to 50/50 solution add acid to water
2. put in braze
3. Cement on copper
4. electrically remove copper
 If this is soldered to copper pipe joints (like refrigeration copper soldered joints), I use a copper sulfate cell to recover the silver, again another discussion.

10. pour down drain
Pour what down the drain? Do not pour anything down your drain, learn to deal with waste

The best I can help here is suggest putting away the chemicals and study, the forum goes into great detail of different ways you could recover the silver safely. The first step would be to study the safety section, and dealing with waste, it will be more valuable than the little bit of silver you can recover from the silver solder braze in rods. If these are unused brazing rod it is worth more as is, short pieces are easily soldered together to make longer rods.


Reactivity series of metals

Metal --Metal Ion--Reactivity
K K+ reacts with water
Na Na+
Li Li+
Ba Ba2+
Sr Sr2+
Ca Ca2+
Mg Mg2+ reacts with acids
Al Al3+
Mn Mn2+
Zn Zn2+
Cr Cr2+
Fe Fe2+
Cd Cd2+
Co Co2+
Ni Ni2+
Sn Sn2+
Pb Pb2+
H2 H+ included for refernce (acids)
Sb Sb2+ highly unreactive
Bi Bi2+
Cu Cu2+
Hg Hg2+
Ag Ag+
Au Au3+
Pt Pt+


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## baja's anvil (Aug 15, 2016)

hello thank you butcher for the response
i am here to learn

you stated '


> 'I personally would use hot concentrated ferric chloride making silver chloride''


how does that work is it more cost effective 

if that’s also out of my league anybody want to buy cadmium bearing silver braze and low silver content 5-15% braze


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## goldsilverpro (Aug 15, 2016)

I always used HCl for making AgCl - with muriatic, about 1ml per gram of Ag. I've also used table salt solution quite a few times - about a gram of dry pure salt per 1.84g of Ag. Never used ferric chloride.


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## butcher (Aug 15, 2016)

The hot concentrated ferric chloride will dissolve the silver contacts, making silver chloride powders, if copper is involved it will also form a copper chloride powder, these can be separated. the solution can be reused over and over with rejuvenation.
I have made some posts on this, I believe one was reusing used copper chloride solutions contaminated with Iron...


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## Grelko (Aug 15, 2016)

goldsilverpro said:


> I've also used table salt solution quite a few times - about a gram of dry pure salt per 1.84g of Ag.



Could you explain this process a bit more and will it work with Ag plating, or contacts?

Edit - I found the long post butcher made about ferric chloride. Very VERY nice information in this.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=46&t=20006


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## butcher (Aug 16, 2016)

It will work with silver plated copper (thin sheet), but it is not a good choice if the copper is very thick. Because you are dissolving a lot of copper, converting it into copper I chloride. Then you have more acid and reagent consumption ...
It works better for silver contacts which are de-soldered or, with contacts clipped from the copper (brass)-- where you have less copper or brass involved to be dissolved. copper does not hurt the process, but the more copper you have the more reagents you will use, like HCl to dissolve the copper I chloride to make it into copper II chloride, to separate the copper chloride from the silver chloride, of course, we can reuse the copper II chloride in other recovery processes, but we normally generate more CuCl2 than we can use anyway, no sense in making more here.

For thick copper plated with silver, I use a large glass bowl set as a copper sulfate cell, small pieces or the cut portions of silver soldered copper refrigeration joints, are bagged as the anode in one of my old cotton socks with no holes in the toe, a piece of copper pipe sticks out of the sock for the connection, the cathode I start our with a very thin sheet of copper (almost a foil), silver normally stays in the bag undissolved what goes into solution is precipitated as slime (which can also be encouraged with small Chloride addition If needed.
A battery charger with a truck headlight in series for the DC power supply.
I may not be getting pure copper from the cell, (it plates well, and looks like copper sea coral), but that is not my goal, I could sell the copper cathodes at the junk yard but I haven't sold any yet, so far I like collecting them.

The copper sulfate is a byproduct from some of my other recovery projects.

A downside is dealing with silver chloride.
side notes:
I two 30 gallon drums of powdered sodium Nitrite I got for free, thinking about using H2O2 to make it into sodium nitrate then distilling some batches of HNO3.
A couple of other projects I have been studying lately are some fusion projects, one is carbide, the other is cyanide I am still in the study phase in these, but both are looking promising.


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## Grelko (Aug 16, 2016)

I should have been more specific to what I had asked. The question I posted, was actually referring to the quote about the "salt solution" that GSP was talking about.

I am greatful that you took the time to explain more about ferric chloride. Any extra information about recovery/refining is always appreciated. Thank you butcher.


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