# Refine silver bar



## saadat68 (Jun 7, 2017)

Hi
If I have a silver bar with 94% silver and 6% manganese 
Can I refine it to 999 silver with a silver cell ? ( just silver cell )


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## saadat68 (Jun 8, 2017)

Does silver cell remove manganese?


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## butcher (Jun 8, 2017)

saadat68,
Sorry I cannot help with the question.
Manganese is easily oxidized, similar to iron in its relation to the periodic chart and some properties.
Mn can have many oxidation states (again similar to iron).

This leads me to question is the manganese an alloy with the silver, or is it already an oxide of manganese (Many of which I think of as refractory metals)? 

Just from its place on the periodic table, my guess is it would oxidize (much easier than silver, possibly to Mn(NO3)2..
So my other questions would be, how easily can it be reduced at the cathode, will it reduce before the silver, will there be enough Mn cations along with all of the Ag cations around the cathode vicinity to become a problem...
I would look for the answers to these questions, I would look for information which discusses problem metals in solution for the silver cell (sometimes some metals are not a problem, the troublemakers sometimes you can find information on how much can be in solution before you begin to have problems (limits).

sorry I do not have any answers only more questions.


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## saadat68 (Jun 9, 2017)

Hi butcher 
Thanks for your post
I don't have answers for your question because I am amateur and also I don't have bar yet. Just I have some silver powders with some manganese oxides powders 

Can I add flux such as KNo3 or NaNo3 to powders and then melt it to oxidize manganese and then go for silver cell ?

And about your second question, do you say *manganese oxides* can reduce and convert to manganese metal in silver cell ?


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## butcher (Jun 10, 2017)

IF these are powders, why not just use nitric acid, then cement the silver, using copper in a displacement reaction to reduce the silver, If the magnesium powders dissolve into Mg(NO3)2, it should not be a problem magnesium is much more reactive in the reactivity series of metals, copper will not replace magnesium from solution.(see reactivity series).
https://en.wikipedia.org/wiki/Reactivity_series


The magnesium nitrate may reduce at the cathode in the silver cell, there the power supply with its excess electrons at the cathode may possibly reduce both the Ag+ and the Mg++ together, the copper cementing process would not.

This would not be my choice, but you could dissolve powders in nitric and use NaCl or HCl to precipitate AgCl, that is If you like dealing with conversion of silver chlorides. The silver chloride would precipitate out leaving other metal chlorides in solution (except Pb, Hg, which are not involved here, see solubility rules).
http://www.csudh.edu/oliver/chemdata/solrules.htm


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## g_axelsson (Jun 11, 2017)

The question was about manganese (Mn), not magnesium (Mg).

I would expect any manganese in a silver bar to dissolve in the electrolyte or maybe become oxidized and end up in the anode slime. I don't know since I've never run into that problem. 6% would foul the electrolyte quite fast though.

Göran


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## saadat68 (Jun 11, 2017)

Thank you
It is manganese oxides not magnesium 
I want to refine my silver without Nitric acid. It is a test


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## 4metals (Jun 12, 2017)

Both silver oxide and manganese dioxide will decompose when you melt them. As silver is a noble metal it will resist forming an oxide more than the manganese so an oxidizer in the flux should put the manganese in the flux leaving the metallic silver behind. 

Since you have to melt the powders for an anode for your silver cell, this step can just become part of the anode making process for this material.


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## saadat68 (Jun 12, 2017)

4metals said:


> Both silver oxide and manganese dioxide will decompose when you melt them. As silver is a noble metal it will resist forming an oxide more than the manganese so an oxidizer in the flux should put the manganese in the flux leaving the metallic silver behind.
> 
> Since you have to melt the powders for an anode for your silver cell, this step can just become part of the anode making process for this material.



Thanks, I have some questions!

1- Do I must separate slag before pouring? I prefer pour melt without separating slag and go for silver cell! ( Because I don't know how to do it without losing my silver )
2- How much flux need for oxidizing of 1 gram of manganese?


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## 4metals (Jun 12, 2017)

You do not have to bail off the slag before pouring, although some refiners prefer to remove most of it with a skimmer. But what remains is poured into the mold and it is separated from the metal with a slag hammer. If you do a lot of bars, a needle scaler is a good tool to have. 

Once you work out what flux will oxidize your impurities, then you have to make sure you have a slag that is glass like so it can be removed easily. Often refiners produce a tenacious slag that is difficult to remove. If this is the case, you want to thin the flux and add chemicals to get that glass like quality back. 



> How much flux need for oxidizing of 1 gram of manganese?



Refining is a science and an art, there is no one, do it this way, for a lot of the techniques used. A lot of variables come into play and the art of the refining is to maximize your method (which you choose because of the equipment and chemicals you have available to you) to each different type of material. 

What you are trying to do is clean up your material before refining it. Once it is clean, yes there are a series of steps which are pretty much standard for clean, or high grade feedstock. But in the cleaning up phase there are too many variables to consider, so there is more of a route you follow with many possible branches to lead you to your desired endpoint. If it was so easy, would anyone be willing to pay you to do this for them? 

You need to start with a flux mixture that will produce the chemical conditions in the molten pool in the crucible to oxidize as many of the undesirable contaminants as possible so they can remain in the slag. You need to take precise notes and use carefully measured ratios of your scrap and your flux blend. And then you need to analyze the result. An XRF is a handy tool to see how effective different flux blends and ratios perform on your specific scrap type. 

Things like the crucible size and the method of mixing the molten charge will affect the result so you need to be consistent so you can track which changes provide the best results. If you are going to specialize in silver batteries, you should be able to come up with a consistent feed material to start your testing with. How big is your furnace? Is it a gas furnace? Smelting and casting anodes isn't something you do with a torch and a melting dish. What type of equipment do you have access to?


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## saadat68 (Jun 13, 2017)

Thank you
This is my furnace :
http://uupload.ir/files/6vwf_5757.jpg


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## 4metals (Jun 13, 2017)

Nice little homemade furnace. I do hope you use it in an exhaust hood and not next to those two pressurized fuel tanks in the photo!

That size furnace, I'm guessing uses a #6 or #8 crucible, is a nice size for smelting smaller lots up to a few hundred ounces. In a hood!


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## saadat68 (Jun 13, 2017)

I don't have a hood for my furnace just I can turn my exhaust fan and go out from my workshop for some minute to evaporate mercury!
And also I observe 2 meter space between my furnace and gas vessels 

I think you say need hood for KNo3
I want to use wet method instead of use flux :?


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## anachronism (Jun 13, 2017)

The evaporating Mercury bit was a joke wasn't it?


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## saadat68 (Jun 13, 2017)

Why?
It's boiling point is 356.7 °C


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## 4metals (Jun 13, 2017)

After the mercury cools down it condenses out of the air. Years ago when refiners did melt amalgam, the little ridges in the exhaust duct were filled with little beads of mercury that cooled and condensed in the ductwork. Mercury will kill you, but if you're bent on suicide, inhaling it as a fume is probably the fastest way! 

Now all amalgam is heated in a retort to eliminate the problem. 

Are you really that naive? If you continue to exhibit just how little you know and how little you care for safety, I will just stop trying to help you! 

All melting should be done under an adequate exhaust hood. Anything else is foolhardy. No other way to put it.


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## saadat68 (Jun 13, 2017)

OK
I didn't see any topic about furnace hood design and ... all of them are about acid fume hood! 
I will melt my silver powder and after that I try to make a hood for second melting. According to my workshop it is very hard to make it. I must to find a solution.
Thanks


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## Topher_osAUrus (Jun 13, 2017)

If there is mercury in your material, the hood would probably serve you better before the first melt, not the second one.


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## 4metals (Jun 14, 2017)

The reason the hoods for chemical usage are covered so often is that they are more difficult to get it to be effective because the fumes are so corrosive. That means you need a blower that will not be eaten by the chemistry, and walls that are somewhat resistant as well. 

For melting any metal blower will suffice and a simple hood over the furnace made of sheet metal will do. 




This hood was for straight karat gold melting, but for smelting and what you are attempting, simply hanging sheet metal walls from the sides and back will increase the effectiveness.


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## saadat68 (Jun 14, 2017)

I know making a hood for furnace is easier than fume hood but I can not make another hole in roof of my rented workshop. Also I don't want add a duct on the wall out of my workshop because it will draw attention 

I will find a solution 

I have some questions:
1- How much furnace fumes is dangerous for me and neighbors ? Is it dangerous like acid fumes ? ( As you know basic problem is Mercury )

2- Do I must add a minimum 3 meter pipe or duct on the roof ? (like acid fume hood)

3- Does my design work and is it safe ? ( If yes please read questions number 4 )

4- How much furnace fumes is hot? Do fumes melt and damage my PVC pipe and impeller of blower. ( If No please read questions number 5 )

5- If fumes aren't very hot to melt PVC pipe and impeller so Mercury vapors condense in pipes before go out with blower. Is it dangerous ? 

Thank You

My design/idea:
http://imgh.us/sdfgh_(2).jpg
http://imgh.us/sdfgh_(3).jpg


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## anachronism (Jun 14, 2017)

Let me get this right.

You're still intending to evaporate mercury and vent it, and you have no idea if it's dangerous or not. 

Am I the only one here who is having grave concerns as to whether you should be doing any of this? I'll just get told off for being too direct no doubt but I'll take the rap willingly if it means saving your life and those of your neighbours. Someone has to say it, and being kind, or polite, or "not wanting to rock the boat" will probably end up costing you your life or others around you.

I think you have a lot more to learn before going any further at all and you need to stop with the mercury right now. In fact stop it all before something terrible happens.


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## 4metals (Jun 14, 2017)

You want to avoid melting anything with mercury if at all possible, you should look into a retort to condense and collect the mercury before melting. http://www.bandmcrushers.com/?page_id=178
The furnace has the potential of getting hot enough to melt the PVC duct, especially in the summer when ambient temperatures are already high. If you get busy enough you will find yourself doing long melts and the heat builds up. And, most important, PVC is flammable. 

You need a separate exhaust for the melting hood. Do you have a metal or refractory chimney for your heating system? If you do you could possibly share the exhaust duct for that system. But I would check with a heating specialist to see if the duct can handle the flow of the heater and the melt hood.


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## 4metals (Jun 14, 2017)

I started writing my last post and did not notice Jon had posted in the interim. I agree with his sentiment completely. Sadat, you seem to have little knowledge about the business venture you have gotten into and little concern for safety, both for yourself and your neighbors.

You are an accident waiting to happen, you need to slow down and do things properly, or find another source for your refining information. GRF will not be party to seeing you create an unsafe condition for you or your neighbors.


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## g_axelsson (Jun 14, 2017)

For anyone wondering where the mercury came from, silver oxide batteries could contain up to 2 grams of mercury per kilo.

There are mercury free silver oxide batteries but there are still produced batteries with mercury in the mix.

Göran


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## saadat68 (Jun 15, 2017)

Thank you
90 percent and maybe 95 percent of my batteries are sony, maxell, made in Japan, USA and Swiss and I don't think there is Mercury in them.

So I think there is 0.2 gram Mercury in one Kilo of silver oxide batteries. Is it really dangerous ? Even I vent Mercury vapors in air? 
I invest all of my money in this business. I rent a workshop. I checked *all of topic* in forum about silver oxide batteries before but *anyone *said that you *must *remove Mercury before melting 
I really can not stop or change my source.
As I testing a new process, maybe can change Mercury to Mercury sulfate and then wash with NaCl solution. ( Mercury sulfate is soluble in NaCl solution- Wikipedia )
And about hood I don't have chimney in my workshop so must find another solution :?


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## Slochteren (Jun 15, 2017)

Maybe you cann find something like this local. I use it wenn melting Copper, Silver etc.

http://www.nederman.com/en/products/family/?catalog=24&category=1705

its meant for welding fumes, comes with build in filters. Don't know if it filters mercury.


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## saadat68 (Jun 15, 2017)

I read a journal that use silver chlorid method that 

Selective precipitation of silver as silver chloride using potassium chloride
A freshly prepared KCl solution of stoichiometric amount was added to the silver nitrate solution to precipitate silver selectively as silver chloride based on the low solubility product constant of AgCl It is worth mentioning that mercury remained in the solution because mercury was in the form of Hg(NO3)2 (Petrucci and Harwood, 1997), which made it possible to precipitate silver selectively.

I can use chloride method 

If I use this method and just melt cement silver, Do I need a hood?


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## g_axelsson (Jun 16, 2017)

saadat68 said:


> Thank you
> 90 percent and maybe 95 percent of my batteries are sony, maxell, made in Japan, USA and Swiss and I don't think there is Mercury in them.
> 
> So I think there is 0.2 gram Mercury in one Kilo of silver oxide batteries. Is it really dangerous ? Even I vent Mercury vapors in air?
> ...


I did a quick search of "silver oxide mercury" and got 50 hits, not all were about silver oxide batteries but most were. The earliest was from 2010, http://goldrefiningforum.com/phpBB3/viewtopic.php?f=38&t=8721&p=81950&hilit=silver+oxide+mercury#p81950

In the afternoon I spent doing research for writing http://goldrefiningwiki.com/mediawiki/index.php/Silver_oxide_batteries I quickly found out that there was mercury in the batteries. Maybe no one specifically wrote that it was a bad idea to melt the batteries as the mercury would evaporate, but I see it like common knowledge that melting anything with mercury would emit mercury fumes.

It is sad that you invested all your money in a workshop without knowing anything about the process you would perform in it. Maybe you should think about stopping in time and take the loss before you lose your health too or hurt some of the neighbors.

Göran


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## saadat68 (Jun 16, 2017)

Thank you 
There are many post about refining batteries but really anyone said that who wants to refine these batteries must find a solution to separate mercury first 
OK, Now in this topic you said :? 
I want to change my process to silver chloride method please read above post


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