Dry Silver Chloride

[Barstool miner]

I have inherited several Kilograms of Dry Silver Chloride. How can I reduce this into Silver metal?

 

[Yggdrasil]

I have inherited several Kilograms of Dry Silver Chloride. How can I reduce this into Silver metal?

You need to grind and smelt it I believe.
Grind it fine and mix it with Sodium Carbonate (?) And smelt it.
There will be losses.

 

[adam mizer]

Silver in chloride form is usually worth more than silver metal if sold.
Is it nice clean and in a labeled bottle/jar?

 

[Yggdrasil]

Silver in chloride form is usually worth more than silver metal if sold.
Is it nice clean and in a labeled bottle/jar?

What is dry Silver Chloride used for?

 

[4metals]

Melting silver chloride

Dry the silver chloride well.

Weigh the chloride and add the following components based on the start weight.

Add 70% of the start weight sodium carbonate, anhydrous (AKA soda ash)

Add 10% of the start weight carbon powder (white baking flour works as a substitute)

Weigh out 40% of the start weight anhydrous borax. Add approximately 1/2 of the borax along with the other ingredients and the silver chloride to a mixing drum and mix well. The efficiency of this process depends on the silver chloride reacting with the other ingredients of the flux to be effective.

Put the well mixed material in a crucible and add the remaining borax as a cap. If the crucible is too small for the entire charge, slowly add more mixed material as the melt proceeds and shrinks down and at the end of the additions add the borax cap.

Melt* using clay bonded crucible you will get pure silver if the silver chloride was well rinsed and all clean silver chloride

* Melt in a gas furnace. This is important for 2 reasons;
* 1, you must melt silver chloride in a clay graphite crucible as the graphite assists in the reduction. Unless you have a low frequency induction furnace the crucibles are not clay graphite and will not work. The graphite liners of newer induction furnaces will be eaten by the reaction.
* 2, the circular circulating flame spirals the smoke efficiently and with the help of a short length of extender pipe gets the dense white smoke up well into your hood.

If good clean silver chloride went in, good pure 99.5% Silver will come out. (Garbage in, garbage out theory!)


No matter how well you do this it will smoke.

 

[goldandsilver123]

I would put the dry silver chloride in a jewelers tumbler with 10% HCl and big heavy iron nails.

Only then melt it

 

[Yggdrasil]

I would put the dry silver chloride in a jewelers tumbler with 10% HCl and big heavy iron nails.

Only then melt it

You mean dissolve or smelt?
There should be no need for smelting if it was wet.
And if it is dry it will not convert well.

 

[goldandsilver123]

It will reduce the amount of AgCl to convert during the melting

the grinding action helps a lot converting dried AgCl

 

[adam mizer]

What is dry Silver Chloride used for?

Checking silver chloride uses:

Silver chloride (AgCl) has various uses, including1234:

• Antimicrobial agent: Used in deodorants and wound healing materials.
• Water treatment: Used to preserve drinking water in tanks.
• Photography: Used in making photographic paper.
• Electroplating and polishing: Used for these purposes.
• Antidote for mercury poisoning: Assists in mercury elimination.

 

[Yggdrasil]

Checking silver chloride uses:

Silver chloride (AgCl) has various uses, including1234:

• Antimicrobial agent: Used in deodorants and wound healing materials.
• Water treatment: Used to preserve drinking water in tanks.
• Photography: Used in making photographic paper.
• Electroplating and polishing: Used for these purposes.
• Antidote for mercury poisoning: Assists in mercury elimination.

I'd guess this is for moist still flowing Silver Chloride?

 

[galenrog]

I'd guess this is for moist still flowing Silver Chloride?

When considering the manufacturing process for each of those, I would think “yes”.

 

[orvi]

Search "Wasyl Kunda Silver Chloride processing". It is modification of above well written procedure. His modification was exact temperature control to produce spongy silver/NaCl solid from which all salts can be washed out with water.
It is relatively old and certainly patented process. There are also the graphs issuing conversion and temperature.

 

[4metals]

His modification was exact temperature control

That may be the challenge for anyone without an induction furnace and a good high range infrared thermometer.

 

[Alondro]

I would think that first converting it to silver oxide with a concentrated NaOH solution would be better if you want to get pure silver. If the silver chloride is high-purity, you'll end up with black silver oxide and a solution of harmless salt water that can be tossed down the drain. Silver oxide reduces to metal MUCH more easily than silver chloride. It will decompose at 280C, so a low-temp smelt just above metallic silver's melting point with just borax flux will do the job.

There's another method to refine silver I'd like to try experimentally. Silver carbonate is also pretty insoluble in water (0.032g/L at 25C), and also decomposes at low temperatures into pure silver. It might work for making high-purity silver free of alkali trace metals, without the need for many washes of the precipitate.

It would only work for silver already free of most base metals, since the carbonates of most transition metals are also insoluble. Have a solution of the mostly pure silver nitrate, drop with sodium carbonate, wash the precipitate with cold distilled water three times to remove the sodium ion, then heat and decompose.

 

[Barstool miner]

You need to grind and smelt it I believe.
Grind it fine and mix it with Sodium Carbonate (?) And smelt it.
There will be losses.

Thank you Yggdrasil, I will try it

 

[orvi]

I would think that first converting it to silver oxide with a concentrated NaOH solution would be better if you want to get pure silver. If the silver chloride is high-purity, you'll end up with black silver oxide and a solution of harmless salt water that can be tossed down the drain. Silver oxide reduces to metal MUCH more easily than silver chloride. It will decompose at 280C, so a low-temp smelt just above metallic silver's melting point with just borax flux will do the job.

There's another method to refine silver I'd like to try experimentally. Silver carbonate is also pretty insoluble in water (0.032g/L at 25C), and also decomposes at low temperatures into pure silver. It might work for making high-purity silver free of alkali trace metals, without the need for many washes of the precipitate.

It would only work for silver already free of most base metals, since the carbonates of most transition metals are also insoluble. Have a solution of the mostly pure silver nitrate, drop with sodium carbonate, wash the precipitate with cold distilled water three times to remove the sodium ion, then heat and decompose.

That NaOH conversion will work nicely with fresh chloride. With dry AgCl (even not wet, just partially dried) it tend to never go to completion and AgCl remains in the mixture unchanged. Maybe prolonged ball-milling would help, but as AgCl dries, it changes something within it´s structure and inhibit "decent" behaviour in alkaline enviroment.

 

[orvi]

That may be the challenge for anyone without an induction furnace and a good high range infrared thermometer.

I would suggest regulated electric furnance is also a fair option here. There is some narrow window of good temperatures, it does not seem impossible to achieve altough good thermometer would be absolutely necessary. My first bet would be K-thermocouple and well regulated (with PID regulator) electric furnance, slowly going to the desired temperature.

But yeah, much more complicated than just capping the crucible with more borax/soda mix and accepting some silver will smoke out (altough with good soda "cap", significant portion of fumes are just NaCl).

 

[eprigge]

I have used the lye and corn syrup/glucose method of reducing AgCl to Ag metal, which works well. Fresh silver chloride is made of tiny particles with a very high surface area and reacts rapidly and completely. As it ages, it clumps together and recrystallizes into a different form with much less surface area, eventually forming large chunks. These chunks are almost like plastic (malleable), you can't crush or grind them easily. The stuff I had was old lab surplus, some very chunky. I found that with the lye/sugar method, even the large chunks reacted internally but I gave them a long time (hours) and a ton of stirring. After the process, I still had some chunks but they were almost all pure silver, with very little AgCl left. I could tell by how much silver I had left after melting them (weight loss).

If you then melt the silver cement in a graphite crucible with sodium carbonate, the remaining traces of AgCl will be reduced to metal. It needs to be a good crucible though with high graphite content. Sodium carbonate will rapidly eat through a crucible with a lot of silica.