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Extracting silver from silver nitrate solution for school project



An ongoing discussion from 2004 through 2015 . . .

(2004)

Q. Hey!

At school I have to work out how to extract silver from Silver Nitrate [linked by editor to product info at Amazon] solution, and I have no idea how to do it! Please can anyone help me?! I only have 4 days left!

Rachel C [last name deleted for privacy by Editor]
student - Lytham St Annes, Lancashire, England


(2004)

A. Firstly, don't leave it so late next time! Secondly, you need to reduce the silver ions to silver metal. This is done with a less noble metal being put into the solution and letting it dissolve. The dissolution process will result in the silver being precipitated out. (Now tell us which less noble metals will do this and how). Alternatively, you can use a reducing agent such as glucose or formaldehyde (very nasty and pongy) and this will throw out silver onto the sides of the vessel.


Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK


(2004)

A. Have a look at letter number 25979, "Recovering silver via electroplating"; that should help you out.

You may want to just read the letter and not actually try to do it as some of the materials needed are not very nice to use.

Chris Dunsmore
metal pre-treatment - Leicester, UK


(2004)

A. The easiest way to extract silver - quantitatively - from silver nitrate solution, is simply adding sodium chloride (table salt) solution. Silver chloride will precipitate and is quite easily decanted and/or filtered. This is probably what they wanted in the first place for you to do. To reduce silver chloride into metallic form is much more complicated. You might wash and wash and wash again the precipitate, then make the reduction with sodium hydroxide and formaldehyde. I do not recommend this to anyone because of the toxicity of formaldehyde.

One easy way is to mix the washed silver chloride into photographic fixer and then electrolyze using graphite anode and stainless steel cathode, to produce silver of 94 to 99% purity.

Arsi Saukkola
metals recycling - Espoo., Finland


(2004)

A. Adding plain copper will work.

Simon Dupay
- Roseville, Minnesota

TUTORIAL FOR NEWBIES:

When a metal is "dissolved" in a solution, it is in "ionized" form (missing some its electrons).

In the specific case of silver nitrate, the formula for the solution is AgNO3, or Ag+ + NO3-. The solution contains silver ions of "plus 1" charge (they are one electron short of being silver atoms) and nitrate ions of "minus 1" charge. To get those silver ions into the familiar form of metallic atoms (Ag0) requires that, somehow, one electron be added to each silver ion. Trevor Crichton starts us off with two possible approaches:

1. A "less noble" metal (copper being a good example) can be immersed into the solution. In this case, copper doesn't attract and hold electrons as powerfully as silver does, and we have Cu0 metal sitting in a solution of Ag+ ions. So the silver ions start "stealing" electrons from the copper and becoming Ag0 atoms while the copper atoms lose the electrons and become Cu++ ions dissolved in solution (Why copper ionizes as Cu++ instead of Cu+ is a subject for another day). You will see the reaction as the copper object becomes silvery looking from the deposition of silver atoms on the surface, while the solution may turn blue because copper ions are blue. Eventually you either run out of silver ions in the silver nitrate solution, or the copper becomes completely coated with silver atoms; in either case the reaction eventually stops.

2. A "reducing agent" such as the glucose or formaldehyde will supply the electrons for the silver to be reduced as a metal. This is how silver-backed glass mirrors and silver Thermos bottles are made. Google "Brashear process" for an introduction.

3. Chris Dunsmore introduces a third way, which is to supply the needed electrons by attaching a piece of metal to each end of a battery and immersing the pieces into the solution without the two pieces touching. As electrons flow out the negative end of the battery, they will reduce the silver ions to silver atoms. This is called electroplating. As he suggests, this one might be better to read about than to actually do.

4. Arsi Saukkolas suggestion has, as he says, the advantage of being "quantitative", i.e., you can remove all the silver from the silver nitrate and determine how much there was. His suggestion involves sort of the inverse of using a noble metal: you use an anion, Cl-, which grabs the silver more powerfully than the NO3- does, with the result that all the silver goes into the form AgCl in place of AgNO3; and the AgCl doesn't stay in solution, but precipitates and drops to the bottom of the beaker.



(2006)

Q. Hi all,

I am very eager to know how would they extract silver from silver nitrate.

if the quantity of silver nitrate is huge, e.g., 1000 litres, and the solution is a mixture of

other metals like copper, aluminium, etc. How can we extract pure silver from this ?

Can anybody suggest the cheapest and efficient way of extracting silver.

regards,

Vijay Patil
- Coimbatore, Tamilnadu, India


(2007)

A. Take the Silver Nitrate solution and add common table salt. The silver will turn to a cottage cheese looking flocculent and drop to the bottom. Filter off the Fluid and neutralize with sodium hydroxide. Then add Sodium Hydroxide slowly and carefully to the flocculent stirring as you go. It will turn the Silver Chloride to silver oxide. Let it dry and then grind it down to powder. Then mix with Borax [linked by editor to product info at Amazon] and smelt in a crucible in a furnace at 1200-1400 °F for 2 hours. Cover the entire mixture with 1/2 inch of Borax on top of the silver oxide/borax mixture.
Once you have complete melt pour into an ingot mold.
Your result will be a very high purity Silver bar.

Ron W [last name deleted for privacy by Editor]
- Seattle, Washington


March 22, 2013

A. Cheapest and safest way to claim high purity silver
Hang a piece of pure (99.9% to 980%) copper bar. For faster results try copper as anode and pure silver rod cathode.
Please follow the above method for safety and it's cheap, good.

Balasaravanan PALANIRAJH
jewellers - Bambalapitiya, Colombo, Sri Lanka



March 14, 2008

Q. So, this site is helpful. But how would I go about extracting silver nitrate from a mixture of sulfur, iron, and silver nitrate? I only have one chance to do it. If I mess up, I'm slightly screwed. Could anyone help me?

Robert Vanity
- Bradford, Vermont


March 14, 2008

A. Robert, you haven't given us much context upon which to expand all of the previous good responses. Where did you get this mix and how do you know what is in it? You have only one chance? Is that because you are a high schooler and this is an exam?

Or are an industrialist? Because if this is not for an academic requirement, I must strongly disagree with your characterization about having only one chance ... a chemist never attempts to react an entire batch based on book knowledge, but only after he has first proven the chemistry with small scale samples does he scale all the quantities up.

If you are a hobbyist, we must warn against the danger of creating explosive silver fulminates if you are fooling with chemistry that you are unfamiliar with. Good luck.

Ted Mooney   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


March 1, 2009

Q. Hi everyone. I was wondering if anyone could help me with a question I got from school. I'm in grade 10 and this is for science class on the topic of chemistry,

"You work for a company with a large quantity of Silver nitrate solution. The company wants to recover and sell the silver metal. Design a process to recover the silver metal from solution"

Please help me.

Carla B [last name deleted for privacy by Editor]
student - Toronto, Ontario, Canada


March 1, 2009

A. C'mon now, Carla. You don't just post your homework assignment and ask someone else to do it for you :-)

You go to the library and study the chemistry of silver nitrate; then propose at least a vague idea or question, and we'll be happy to help you. If you're going to skip the library, at least read the suggestions from Arsi Saukkola and Ron W. Thanks!

Regards,

Ted Mooney, finishing.com   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

February 18, 2010

A. Hey that is really cool! I have to do that too! What I am going to do is get five different metal strips and put them into the solution to see which one attracts the most silver. You may not have the access to the metals and they take some time to be shipped. you only have 4 days so I don't recommend waiting! That is my only way to do this. Sorry! Maybe it can be of some help to you! My dad is a chemist so that is what he told me to do! Good luck with this! I do hope that you succeed.

Molly k [last name deleted for privacy by Editor]
- Batavia, New York

Metal Samples



April 14, 2013

Q. Hi ...
Right now I doing a project on recovery of silver, copper, zinc and cadmium from nitrate leach solution by solvent extraction.
When I add sodium hydroxide to raise pH from 0.33, then a large amount of precipitate is observed. Please anyone tell me how I minimize this problem.
Also suggest which extractent I can use as selective to silver, copper, zinc and cadmium in which pH range.

Sohil Nasit
Student - Vadodara, Gujarat, India


April 15, 2013

A. Hi Sohil. It seems to me that if you simply raise the pH you'll precipitate all of those heavy metals together. I know less about this than you do, but I do see good discussions above about either precipitating the silver with table salt, or plating it out by displacement onto solid copper.

Please try your very best to frame your question in terms of what has already been offered, because it is the kiss of death to the thread if readers feel that you are blowing off their previous input.

Regards,

Ted Mooney, finishing.com   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


November 21, 2013

Q. Hi all! I am about to begin reclaiming high purity silver metal from a solution of silver nitrate, made from scrap silver and 70% fuming nitric acid, by precipitating with copper. As it turns out, the copper metal can be reclaimed after all the silver is removed by adding aluminum. Does anyone know how is the best way to neutralize the solution for disposal after adding the aluminum? Is it possible to return the nitric acid to a state that will dissolve silver without losing too much volume or potency? I have 1/2 US gallon of acid, and at the end of the process expect to have at least 1 US gallon that will undoubtedly be diluted with distilled water.

Thanks!

MARCUS BREWER
- Florence, Alabama



Electrolytic extraction of silver using silver trioxonitrate solution

May 12, 2014

Q. Hi guys. Please can anyone one tell me how I can do this assignment:
Electrolytic extraction of silver using silver trioxonitrate(v)solution.

Thanks.

Gostime mathias
- Port Harcourt, Rivers state, Nigeria


May 2014

A. Hi Gostime. Your teacher provided you no instructions, guidebook, method, or context? Most of all, no objective -- just "Do it!"?

In that case, take two 2-foot long lengths of copper wire, and coil most of their lengths around separate pencils, then remove the pencils. Attach the uncoiled ends to each pole of a 1-1/2 bolt "D" cell battery and don't let the wires touch. Put the coiled ends into a beaker (again, don't let them touch). Put your silver trioxonitrate solution into the beaker. One of the two wires will turn silvery. As soon as you see some silver on it you have electrolytically extracted silver using silver trioxonitrate solution, and have completed the assignment. Good luck.

Regards,

Ted Mooney, finishing.com   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

May 23, 2014

A. Hi Gostine

After a (very) long career as a professional chemist, I have never heard of trioxonitrate (v)

You will find that you will find the answer more easily if you refer to silver nitrate.

Trioxonitrate is not recognised by the International Union of Pure And Applied Chemistry IUPAC who are responsible for naming chemicals. Using a non standard name for common chemicals has serious safety implications.

geoff smith
Geoff Smith
Hampshire, England



January 14, 2015

Q. Here is my situation:

I would like to precipitate pure (or as pure as possible) silver from a solution of silver Nitrate. My belief in most of these cases is that the solution is mostly pure aqueous silver nitrate.
My first plan: To use clean/non-coated copper wire to reduce AgNO3 into Ag(s) and Cu(II) NO3

I then will test the silver precipitate's boiling pt. to get a general idea as to its purity.

My second plan if there are impurities: AgNO3 + NaCl > AgCl + NaNO3
Then: AgCl + NH3 to make new solution

Is it possible/safe to redox the AgCl and Ammonia solution with Cu (or similar metal) to precipitate a purer silver?

Should I get in touch with an ICP operator to test the AgCl purity?

I am a facility Chemist in a Haz Waste facility that wants to perform this reaction in order to get pure silver for jewelry making with the goal of working with silver smith to make my wedding rings.

Luke Moran
- Burlington, Vermont USA
  ^- Privately contact this inquirer -^


January 17, 2015

Q. I will be performing a simple Redox reaction to precipitate silver from AgNO3 using a solid copper rod.

I have two questions.

1. Most copper rods come with some sort of oxide coating. How might I safely and completely remove (either chemically or physically) this coating so as not to precipitate a impure silver.

2. I want to also try removing any trace metals from the silver nitrate solution with sodium chloride. How easy it is to then precipitate silver from AgCl?

Luke Moran
- Burlington, Vermont USA


January 2015

A. Hi Luke.
1. Sandpaper or scotchbrite should easily remove any coating on your copper rod. Then rinse off the dust with water, and immerse it.
2. You won't be able to remove the trace metals once you've placed the copper rod in it because for each two atoms of silver deposited on the copper rod, one atom of copper dissolves into solution ... and sodium chloride will not precipitate the copper; rather, it will stay in solution.

Oops, I replied to your 2nd letter before I noticed the first :-(
-- so let's see what others have to say.

Regards,

Ted Mooney, finishing.com   Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


January 18, 2015

A. Hi Luke

Ammonia can react with silver salts to give a range of highly sensitive explosive compounds.

In a Haz Chem facility you should know this

The simple answer to your question is to simply stir in some (clean degreased)steel wire wool and stir.

Geoff Smith
Hampshire, England


January 18, 2015

A. Whether you use copper to cement the silver or use a chloride to precipitate silver chloride, about the only source of contamination will be the solution mixed in with the solids. The solids themselves are of high purity. The more you rinse these solids, the higher the purity of the silver. Hot water rinses are best.

I would absolutely avoid the use of copper wire for cementation. The cemented silver intermingles with the wire and makes separation difficult. Also, the small wire tends to dissolve and release slivers of copper that contaminate the silver. The best copper to use is bare scrap copper buss bar (say, 1/4" X 2" or 3") that contains no solder and is not plated with tin or silver. Put the silver solution in a plastic 5 gallon bucket and use 5 or 6 lengths of buss bar. The pieces of buss bar should be long enough to stick up out of the solution so you could easily remove them

I would advise against steel wool. It's easy to do but recovery of the silver is more difficult.

All in all, if you want fine silver (at least 999.0 fine) you will have to put the recovered silver through an electrolytic silver cell. Chemically processed silver, no matter what process you use, will not normally meet the accepted 999.0 fineness requirement. There is an oxalic acid process that may reach this purity, but it is tricky.

Chris Owen
- Nevada, Missouri, USA


January 30, 2015

A. I have prepared the reagent which directly precipitates elemental silver from silver nitrate solution; watch the video on you tube.

Daulat Bhosale
- Bangkok Thailand


February 26, 2015

A. Please use hydrazine hydrate to reduce silver from silver nitrate solution .

bhupesh mulik
CAC admixture - mumbai,india


June 20, 2015

Q. Hi. I use hydrazine hydrate to precipitate gold. Can this chemical be used to precipitate silver also? And, if yes, then should I neutralize the silver nitrate solution with urea first or directly use the chemical?

Santosh pai
- mysore Karnataka India

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